scholarly journals Elucidation of the IMiDs-Resistant Mechanism and Development of the Overcoming Drugs Inducing CRBN Independent G2/M Cell Cycle Arrest in Myeloma Cells

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4451-4451
Author(s):  
Ryo Uozaki ◽  
Shuji Aida ◽  
Takasi Yamagughi ◽  
Tomofumi Yamamoto ◽  
Sho Kashiwazaki ◽  
...  
Keyword(s):  
Cell Death ◽  
High Risk ◽  
Molecular Mechanism ◽  
Cell Lines ◽  
Research Funding ◽  
Water Solubility ◽  
Xenograft Model ◽  
Genetic Mutation ◽  
Resistant Cell ◽  
Tubulin Polymerization

Abstract [Introduction] Recent development of novel drugs significantly improved prognosis of Multiple Myeloma (MM). Immunomodulatory drugs (IMiDs) and proteasome inhibitors play central roles in MM therapy. However expanded usage of lenalidomide (Len) has increased the number of Len-resistant patients. And limited information is obtainable with regand to Len-resistant mechanism, such as overexpression and genetic mutation of IMiDs-binding protein, celeblon (CRBN); thus, elucidating the Len-resistant mechanism and development of drugs overcoming the Len-resistance are very important for improving the outcome of MM. The purposes of this study are [1] to clarify the molecular mechanism of Len-resistance using Len-resistant MM cell lines [2] to confirm the mechanism of CRBN independent myeloma cell death by novel phthalimide-derivatives, TC11 and PEG(E)-TC11. [Method] [1] In our laboratory, Len-resistant cell lines, KMS21R, KMS27R and MUM24R have been established by long-term co-culture with low-dose Len. Using these cell lines, we examined expression of CRBN and the downstream molecules, IKZF1/3, IRF4 and c-MYC by western blotting. We also examined the mutation of CRBN in KMS27R. [2] We have originally developed a novel phthalimide-derivative, TC11 and PEG(E)-TC11 synthesized for improving water solubility. We examined whether TC11 and PEG(E)-TC11 induced cell death to Len-resistance MM or not. [Result] [1] First, we validated expression of CRBN and the down-stream molecules, which mediate pharmacological action of Len. Decreased expression of CRBN and subsequent up-regulation of down-stream IKZF1 were confirmed in KMS21R cell. In KMS27R cell, IKZF 1/3 expressions are increased without alteration of CRBN expression level. Thus, genetic mutation in CRBN or IKZF1 is suspected in KMS27R cells. In MUM24R cell, no significant change in the expression levels of the CRBN pathway molecules was confirmed, suggesting other molecular alternation than CRBN pathway. [2] TC11 significantly induced apoptosis of Len-resistant cells. We have previously reported that TC11 didn't bind to CRBN and TC11 directly bound to nucleophosmin1 (NPM1) and α-tubulin. It was found that TC11 induced G2/M arrest and subsequent apoptosis by inhibition of tubulin polymerization and NPM1 oligomerization. Fluorescence microscopy observation showed that TC11 treatment induced hyper duplication of centrosomes in MM cells. Water solubility and blood absorption of PEG(E)-TC11 were significantly improved compared with those of TC11. As a consequence, PEG-(E)TC11 significantly delayed tumor growth in xenograft model mice. [Discussion & Conclusion] [1] Our present data suggested diversity of Len-resistant mechanism in MM patients. For example, in KMS21R, decreased expression of CRBN was likely the cause of Len-resistance. In KMS27R, genetic mutation in CRBN-IKZF1 pathway caused inhibition of IKZF1 degradation. In MUM24R, the Len-resistant mechanism didn't relate to the CRBN pathway but to unknown molecular mechanism. Len-resistant cell lines are useful tools for studying Len-resistant mechanisms and developing drugs overcoming Len-resistance. [2]TC11 abrogated tubulin polymerization and NPM1 oligomerization, induced centrosome disruption and G2/M arrest. Since G2/M check point doesn't closely rely on p53. TC11 was able to induce apoptosis of MM cells with high-risk cytogenetic mutations such as deletion of TP53 gene. TC11 and PEG-(E)TC11 are expected as a candidate compound overcoming Len-resistance and high-risk MM. Disclosures Matsushita: Amgen: Research Funding. Hattori:Takeda: Research Funding; IDAC inc.: Research Funding.

Mechanisms of Acquired Resistance to Venetoclax in Preclinical AML Models

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 328-328 ◽  
Author(s):  
Qi Zhang ◽  
Rongqing Pan ◽  
Lina Han ◽  
Ce Shi ◽  
Stephen E. Kurtz ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Lines ◽  
Small Molecule ◽  
Research Funding ◽  
Synergistic Effects ◽  
Acquired Resistance ◽  
Parental Cell ◽  
Resistant Cell ◽  
Flt3 Inhibitors ◽  
Resistant Cells

Abstract BH3-mimetic ABT-199 (venetoclax, VEN) is a selective small-molecule antagonist of the anti-apoptotic BCL-2 protein. It binds to BCL-2 specifically, causing the release of pro-apoptotic BAX and BH3-only proteins and induction of cell death. Our studies indicated that AML is a BCL-2 dependent disease that, in pre-clinical studies, responds robustly to VEN by induction of apoptotic cell death (Pan et al., Cancer Discovery 2014). As a single agent, VEN demonstrated clinical activity in relapsed/refractory AML, yet patients who initially responded ultimately developed resistance and progressed. In this study we investigated mechanisms of acquired resistance to VEN in preclinical AML models. First, we generated 5 VEN-resistant cell lines (OCI-AML2, Kasumi, KG-1, MV4;11 and Molm13; with VEN cell-killing IC50s of 0.021µM, 0.046µM, 0.073µM, 0.020µM and 0.050µM, respectively) by exposing the cells to gradually increasing VEN concentrations. The IC50s of resistant cells are 15.2µM, 5.7µM, 31.6µM, 11.4µM and 15.4µM (124-723-fold greater than their parental counterparts). Protein analysis of resistant cells using immunoblotting demonstrated increased expression of MCL-1, a known resistance factor to VEN, in 4 resistant cell lines (OCI-AML2, KG-1, Mv4;11 and Molm13); and BCL-XL increase in MV4;11 and Molm13 resistant cells. To characterize the functional role of MCL-1 and BCL-XL in resistance to VEN, we co-treated parental and resistant cells with novel MCL-1 and BCL-XL- selective inhibitors (A-1210477 and A-1155463). The combination of VEN with A-1210477 or A-1155463 showed synergistic growth inhibition in all 5 parental cell lines (combination indices (CI) for A-1210477 were 0.15-0.62; CI for A-1155463 were 0.33-0.51, except >3 for KG-1). Notably, 4 out of 5 resistant cell lines (OCI-AML2, Kasumi, MV4;11, Molm13) became more sensitive to MCL-1 selective inhibitor A-1155463 but not to BCL-XL inhibitor A-1210477. However, no further effects were seen in resistant cells when combined with VEN. We next compared sensitivity of three paired parental and resistant cell lines (OCI-AML2, MV4;11 and Molm13) to a library of 130 specific small-molecule inhibitors (Tyner, et.al.. Cancer Res. 2013). Cells were co-treated with VEN and each specific inhibitor, and drug target scores were calculated based on the IC50 of measured effectiveness of panel drugs against the cells. The screening revealed modulation of sensitivity to mTOR, MEK, and FLT3 pathways in resistant cells (Fig.1C). To confirm these findings, we next co-treated AML cells with VEN and specific inhibitors of the mTOR pathway (rapamycin and AZD2014) or MEK pathway (CI1040) in all 5 paired parental and resistant cell lines; or with FLT3 inhibitors (quizartinib and sorafenib) in parental and resistant MV4;11 and Molm13, which harbor FLT3-ITD. The combination of VEN and AZD2014 achieved synergistic effects in all 5 parental cell lines (CI AZD2014: 0.08-0.94), and VEN/rapamycin were synergistic in 3 parental cell lines (CI rapamycin: 0.00-0.55, except 1.76 for KG-1 and 1.59 for Molm13). Combination of VEN with CI1040 achieved synergy in OCI-AML2, Kasumi, MV4;11 and Molm13 parental cell lines (CI: 0.14-0.61). Finally, VEN/FLT3 inhibitors achieved synergistic effects in MV4;11 and Molm13 parental cell lines (CI quizartinib: 0.66-0.69; CI sorafenib: 0.64-0.71). The resistant cell lines exhibited sensitivity to these inhibitors as single agents, and no synergistic effects were seen when combined with VEN. We have further induced in vivo resistance in two primary AML xenografts by treating NSG mice engrafted with 2nd passage AML cells with 100 mg/kg Q.D. VEN for 4 weeks followed by harvest of leukemic cells that repopulated the mouse after treatment discontinuation. While the proteomics, gene expression (RNAseq) and drug screening assays are in progress, preliminary immunoblotting studies demonstrated decreased expression of BCL-XL and BCL-2 (Fig.1B). In summary, we identified multiple mechanisms of acquired resistance to VEN, which ultimately modulate the balance between pro- and anti-apoptotic BCL-2 family members. Our studies indicate that upfront combination of VEN with selective inhibitors of MCL-1, or with inhibitors of specific signaling pathways, can synergistically induce apoptosis in AML cells and conceivably prevent emergence of VEN resistance. Disclosures Leverson: AbbVie: Employment, Equity Ownership. Tyner:Aptose Biosciences: Research Funding; Constellation Pharmaceuticals: Research Funding; Janssen Pharmaceuticals: Research Funding; Array Biopharma: Research Funding; Incyte: Research Funding. Konopleva:Novartis: Research Funding; AbbVie: Research Funding; Stemline: Research Funding; Calithera: Research Funding; Threshold: Research Funding.

scholarly journals Upregulation of MAPK/MCL-1 Maintaining Mitochondrial Oxidative Phosphorylation Confers Acquired Resistance to BCL-2 Inhibitor Venetoclax in AML

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 101-101 ◽  
Author(s):  
Qi Zhang ◽  
Lina Han ◽  
Ce Shi ◽  
Rongqing Pan ◽  
Man Chun John MA ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Lines ◽  
Research Funding ◽  
Acquired Resistance ◽  
Resistant Cell ◽  
Mitochondrial Activity ◽  
Mitochondrial Oxidative Phosphorylation ◽  
Expression Of Genes ◽  
Apoptotic Proteins ◽  
Resistant Cells

Abstract ABT-199 (venetoclax), a selective small-molecule antagonist of the anti-apoptotic protein BCL-2, enables the activation of pro-apoptotic proteins and the induction of cancer cell death. Our previous studies found that AML is a BCL-2 dependent disease and responds robustly to venetoclax by induction of apoptotic cell death (Pan et al., Cancer Discovery 2014). Despite initial responses to single agent venetoclax in a Phase II trial of relapsed AML, patients ultimately developed resistance and progressed (Konopleva et al., Cancer Discovery 2016). In this study we investigated mechanisms of acquired resistance to venetoclax in preclinical AML models. First, we generated 5 AML cell lines resistant to ³1µM venetoclax. No BAX (exon5 and 6) or BCL2 (exon2) mutations were found in resistant cells. Immunoblotting analysis demonstrated increased expression of anti-apoptotic proteins MCL-1, BCL-2 A1, and BCL-XL, and a decrease of pro-apoptotic PUMA protein in selected resistant cell lines. To probe the functional interactions between the pro- and anti-apoptotic proteins, we next performed co-immunoprecipitation (co-IP) studies. The anti-BIM and anti-MCL-1 co-IPs revealed reduced levels of BIM:BCL-2 complexes and increased BIM:MCL-1 complexes in resistant cells compared to their parental counterparts (Fig 1B). The BH3 profiling technique examines mitochondrial sensitivity to different BH3 mimetic peptides, and has proven to be a useful tool to determine cell dependence on anti-apoptotic BCL-2 family proteins. BH3 profiling demonstrated that resistant cells had increased responses to NOXA, MS1 and HRK peptides, indicating increased dependence on MCL-1 and/or BCL-XL (Fig 1C). To characterize the functional role of MCL-1 in resistance to venetoclax, we co-treated parental and resistant cells with selective BCL-XL or MCL-1 inhibitors A-1155463 (Leverson et al. Science Transl Med 2015) and A-1210477 (Leverson et al., Cell Death Dis 2015). The combination of venetoclax with either A-1155463 or A-1210477 showed synergistic growth inhibition in all 5 parental cell lines. Notably, 4 of the 5 resistant cell lines (OCI-AML2, Kasumi, MV4-11, MOLM13) became more sensitive to an MCL-1 inhibitor but not to a BCL-XL inhibitor (Fig 1E). However, no further sensitization was seen in combination with venetoclax in resistant cells. To characterize additional mechanisms of resistance to venetoclax in AML cells, we conducted RNA sequencing of single cell clones (2 clones/cell line) isolated from paired isogenic cells (OCI-AML2, MV4-11, MOLM13). Analysis of RNA expression patterns by gene set enrichment analysis (GSEA) revealed elevated expression of genes in the RAS/MAPK pathway (Fig 1F), consistent with increased p-ERK and p-p90-RSK protein levels (Fig 1G). Inhibition of MAPK with MEK inhibitor GDC-0973 reduced MCL-1 expression in parental but not in resistant cells, indicating that MAPK activation partially contributed to high MCL-1 levels (Fig 1G). GSEA of RNAseq data further uncovered altered expression of genes involved in mitochondrial oxidative phosphorylation (OxPhos) in 3 resistant cell lines with high MCL-1 expression (OCI-AML2, MV4-11 and MOLM-13). Notably, BCL-2 was reported to sustain AML stem cell survival through maintenance of the mitochondrial activity of OxPhos (Lagadinou etal., Cell Stem Cell, 2013). Analysis of mitochondrial respiration using a Seahorse Bioanalyzer demonstrated similar levels of oxygen consumption rate (OCR) in parental and resistant cells. Inhibition of BCL-2 with 100nM venetoclax for only 2 hrs. fully blocked baseline and maximal respiratory activity in parental but not in resistant cells. In turn, inhibition of MCL-1 with A-1210477 inhibited respiration in both parental and resistant cells, indicating a role for MCL-1 in sustaining mitochondrial activity in venetoclax-resistant AML cells, which can maintain unperturbed mitochondrial function. In summary, we identified a novel mechanism of resistance to targeted BCL-2 inhibition through upregulation of MAPK leading to increased levels of anti-apoptotic MCL-1 that binds and neutralizes BIM and maintains the mitochondrial OxPhos pathway in AML cells. Concomitant inhibition of BCL-2 and MCL-1, or of BCL-2 and OxPhos could induce synergistic cell death in AML and conceivably prevent the emergence of venetoclax resistance. Disclosures Tyner: Constellation Pharmaceuticals: Research Funding; Janssen Research & Development: Research Funding; Agios Pharmaceuticals: Research Funding; Genentech: Research Funding; Array Biopharma: Research Funding; Inctye: Research Funding; Seattle Genetics: Research Funding; Aptose Biosciences: Research Funding; AstraZeneca: Research Funding; Takeda Pharmaceuticals: Research Funding; Leap Oncology: Consultancy. Leverson:AbbVie: Employment, Other: Shareholder in AbbVie. Letai:Astra-Zeneca: Consultancy, Research Funding; Tetralogic: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding. Konopleva:Calithera: Research Funding; Cellectis: Research Funding.

Inhibition of MDR1 Overcomes Brentuximab Vedotin Resistance in Hodgkin Lymphoma Cell Line Model and Is Synergistic with Brentuximab Vedotin in Mouse Xenograft Model

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 752-752 ◽  
Author(s):  
Robert W Chen ◽  
Jessie Hou ◽  
Indu Nair ◽  
Jun Wu ◽  
Tim Synold ◽  
...  
Keyword(s):  
Cell Lines ◽  
Research Funding ◽  
Xenograft Model ◽  
Resistant Cell ◽  
Brentuximab Vedotin ◽  
Mouse Xenograft ◽  
Mouse Xenograft Model ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

Abstract Background: Classical Hodgkin lymphoma (HL) expresses surface CD30. Brentuximab vedotin (BV) is an antibody-drug conjugate that selectively delivers a potent cytotoxic agent, monomethyl auristatin E (MMAE), specifically to cells expressing surface CD30. Although BV elicits a high response rate (75%) in HL, patients who do not achieve complete response (CR) will eventually develop resistance to BV. We have developed 2 BV-resistant HL cell models and shown that resistance to BV is due to MDR1 upregulation rather than downregulation of surface CD30. MDR1 upregulation leads to increased drug exporter pump and decreased intracellular MMAE, the cytotoxic agent in BV. Our hypothesis is that by inhibiting MDR1, we can overcome resistance to BV and also achieve synergy with BV in HL cell lines and mouse xenograft model. Methods: HL cell lines (L428 and KMH2) were used for in vitro experiments. The selection of BV resistant cell model (L428R and KMH2) was done using pulsatile treatment with BV. Both BV resistant cell models were confirmed with MTS assay and cell growth assays. MDR1 upreguation was confirmed by qRT-PCR and western blot. Intracellular MMAE concentration was assessed by mass spectrometry. MDR1 inhibitors verapamil (VrP, 10 ug/ml) and cyclosporine (CsA, 5 uM) were chosen. NSG mice were used for mouse xenograft experiments. Results: MTS assay showed that the IC50 to BV increased 12 folds in L428R (32 ug/ml in L428, 391 ug/ml in L428R), and that the IC50 to BV has increased 17 folds in KMH2R (13 ug/ml in KMH2, 219 ug/ml in KMH2R). QRT-PCR shows that L428R and KMH2R had upregulation of MDR1 mRNA, and western blot shows L428R and KMH2R had overexpression of PgP (MDR1) as compared to L428 and KMH2. Mass spectrometry shows that the intracellular MMAE concentration was 7.6 folds lower in L428R as compared to L428 after treatment with BV. We then examined the effect of MDR1 inhibitors (VrP and CsA) on the IC50 of BV in L428R and KMH2R. The addition of VrP to L428R was able to decrease the IC50 from 344 ug/ml to 22.8 ug/ml (15 fold). The addition of VrP to KMH2R was able to decrease the IC50 from 170 ug/ml to 22 ug/ml (7.7 fold). The addition of CsA to L428R was able to decrease the IC50 from 275 ug/ml to 0.0068 ug/ml (40441 fold). The addition of CsA to KMH2 was able to decrease the IC50 from 129 ug/ml to 0.11 ug/ml (1098 fold). Also, the addition of VrP to L428R was able to increase the intracellular MMAE levels of L428R by 6.4 folds. We then examined the effect of MDR1 inhibitors plus BV in BV naïve parental cell lines. The addition of VrP to L428 was able to decrease the IC50 of BV from 69 ug/ml to 0.03 ug/ml (2300 folds). The addition of VrP to KMH2 was able to decrease the IC50 of BV from 6.3 ug/ml to 0.0013 ug/ml (4846 folds). The addition of CsA to L428 was able to decrease the IC50 of BV from 36 ug/ml to 0.0085 ug.ml (4235 folds). The addition of CsA to KMH2 was able to decrease the IC50 of BV from 7.1 ug/ml to 0.0002 ug/ml (32645 folds). Neither the VrP or CsA had individual effects on HL parental or resistant cell lines. Because CsA seems to have the strongest effect in KMH2 cell lines, we examined the effect of CsA plus BV in KMH2 mouse xenograft model. KMH2 was injected into the right flank of the mice to form subcutaneous lymphomas and mice were separated into 3 groups of 5. Group 1 is control without addition of BV or CsA. Group 2 is control plus BV at dose of 0.3 mg/kg intravenously every 4 days. Group 3 is treated with BV at doses of 0.3 mg/kg intravenously every 4 days and CsA intraperitoneally at 15 mg BID. We show that group 2 had a 37% reduction in tumor volume as compared to group 1 and that group 3 had a 70% reduction in tumor volume as compared to group 1 (Figure 1). Conclusion: MDR1 upregulation increases efflux pump activity and decreases intracellular accumulation of MMAE, and leads to resistance to BV in HL. This mechanism of resistance can be overcome with MDR1 inhibitors VrP and CsA. The addition of MDR1 inhibitors to BV is able to increase the intracellular accumulation of MMAE, and restore the sensitive to BV. We are also able to show synergery between MDR1 inhibitors and BV in the parental non-resistant HL cell lines and mouse xenograft model. This is the first study showing synergy between MDR1 inhibition and antibody drug conjugates. A clinical trial has been initiated to examine the safety/efficacy of the combination of MDR1 inhibitors plus BV in patients with relapsed/refractory HL. Figure 1. Figure 1. Disclosures Chen: Seattle Genetics: Consultancy, Honoraria, Research Funding, Speakers Bureau; Merck: Consultancy, Research Funding; Millenium: Consultancy, Research Funding, Speakers Bureau; Genentech: Consultancy, Speakers Bureau. Kwak:Antigenics: Equity Ownership; Celltrion: Consultancy; XEME BioPharma: Consultancy, Equity Ownership; Sella Life Sciences: Consultancy.

scholarly journals Characterization of Mechanisms Underlying Acquired Venetoclax-Resistance in Mantle Cell Lymphoma: BDA-366 As a Potential Treatment Option

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1580-1580
Author(s):  
Daniela Steinbrecher ◽  
Felix Seyfried ◽  
Johannes Bloehdorn ◽  
Billy Michael Chelliah Jebaraj ◽  
Lüder Hinrich Meyer ◽  
...  
Keyword(s):  
Cell Death ◽  
Board Of Directors ◽  
Cell Lines ◽  
Research Funding ◽  
Cell Lymphoma ◽  
Resistant Cell ◽  
Advisory Committees ◽  
Apoptotic Protein ◽  
Mantle Cell ◽  
Resistant Cells

Abstract In many cancers the equilibrium of pro- versus anti-apoptotic BCL-2 proteins is deregulated. BCL-2 inhibitors like Venetoclax (VEN) have been shown to be highly active drugs in BCL-2 dependent cancers like chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL). Despite being highly efficient in cell killing, resistance to VEN can be acquired over time. In addition to understanding the underlying mechanisms of resistance to VEN it is important to identify additional treatment options. BDA-366 is a BCL-2 inhibitor with a different mode of action than the BH3 mimetic VEN. BDA-366 acts by inhibiting the BH4 domain and thereby inducing a conversion of anti-apoptotic BCL-2 into a pro-apoptotic protein. BDA-366 showed high effectivity in inducing apoptosis in CLL cells, in primary as well as in cell lines, while all of the CLL cell lines (n=7) tested were resistant to VEN. Furthermore all of the MCL cell lines (n=5) tested were sensitive to the treatment with BDA-366 while only a subset (3 out of 5) responded to treatment with VEN. In order to investigate whether BDA-366 would be a treatment option for VEN-resistant patients, we generated VEN-resistant MCL cell lines (MINO and MAVER-1) by chronic exposure to the drug. In the resistant cell lines, BCL-2 protein levels were not deregulated. In variance to previous reports in diffuse large B cell lymphoma (DLBCL) (Choudhary et al, Cell Death Dis 2015), resistance in MCL cell lines was not mediated by MCL-1 upregulation. In VEN-resistant MINO cells, MCL-1 expression was similar to the parental cells, while MCL-1 was significantly downregulated in VEN-resistant MAVER-1 cells. In contrast, VEN-resistant MCL cell lines showed BCL-XL upregulation as compared to parental cells, which is in line with results obtained in DLBCL (Choudhary et al, Cell Death Dis 2015). Furthermore, dynamic BH3 profiling validated a dependency on BCL-XL in resistant cells and confirmed that resistance was not mediated by MCL-1. The significance of BCL-XL in mediating resistance to VEN was underlined by additional experiments using navitoclax. In contrast to VEN, navitoclax inhibits BCL-2, BCL-XL and BCL-W and was sufficient to induce apoptosis in both parental and resistant cells. In contrast to the BH3 domain inhibitor VEN, the BCL-2 inhibitor BDA-366 acts by converting BCL-2 into a pro-apoptotic molecule. BDA-366 efficiently induced dose dependent apoptosis in VEN-resistant cells. MINO as well as MINO VEN-resistant cells showed the same sensitivity to BDA-366 while VEN-resistant MAVER-1 cells showed reduced sensitivity to BDA-366 as compared to the parental cells. However, with increased BDA-366 concentrations efficient cell killing was achieved in the VEN-resistant cell lines Overall, these results suggest that VEN-resistance is mostly mediated by permanent upregulation of BCL-XL. BCL-2 levels are not deregulated upon development of resistance to VEN. The inhibition of the BH4 domain and thereby converting BCL-2 into a pro-apoptotic protein proved to be a promising therapeutic option even in cancers with acquired resistance to VEN. Disclosures Döhner: Pfizer: Research Funding; Amgen: Consultancy, Honoraria; Jazz: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; Agios: Consultancy, Honoraria; Pfizer: Research Funding; AROG Pharmaceuticals: Research Funding; Bristol Myers Squibb: Research Funding; Astex Pharmaceuticals: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AROG Pharmaceuticals: Research Funding; Astellas: Consultancy, Honoraria; Astellas: Consultancy, Honoraria; Agios: Consultancy, Honoraria; Astex Pharmaceuticals: Consultancy, Honoraria; Celator: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Celator: Consultancy, Honoraria; Jazz: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Research Funding; Janssen: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding. Stilgenbauer:Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffmann La-Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genzyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmcyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

scholarly journals Combined Inhibition of AKT and KIT Restores Expression of Programmed Cell Death 4 (PDCD4) in Gastrointestinal Stromal Tumor

Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3699
Author(s):  
Marya Kozinova ◽  
Shalina Joshi ◽  
Shuai Ye ◽  
Martin G. Belinsky ◽  
Dinara Sharipova ◽  
...  
Keyword(s):  
Cell Death ◽  
Gastrointestinal Stromal Tumor ◽  
Cell Lines ◽  
Synergistic Effects ◽  
Single Agent ◽  
Xenograft Model ◽  
Stromal Tumor ◽  
In Vivo Studies ◽  
Preclinical Model ◽  
Kit Mutation

The majority of gastrointestinal stromal tumor (GIST) patients develop resistance to the first-line KIT inhibitor, imatinib mesylate (IM), through acquisition of secondary mutations in KIT or bypass signaling pathway activation. In addition to KIT, AKT is a relevant target for inhibition, since the PI3K/AKT pathway is crucial for IM-resistant GIST survival. We evaluated the activity of a novel pan-AKT inhibitor, MK-4440 (formerly ARQ 751), as monotherapy and in combination with IM in GIST cell lines and preclinical models with varying IM sensitivities. Dual inhibition of KIT and AKT demonstrated synergistic effects in IM-sensitive and -resistant GIST cell lines. Proteomic analyses revealed upregulation of the tumor suppressor, PDCD4, in combination treated cells. Enhanced PDCD4 expression correlated to increased cell death. In vivo studies revealed superior efficacy of MK-4440/IM combination in an IM-sensitive preclinical model of GIST compared with either single agent. The combination demonstrated limited efficacy in two IM-resistant models, including a GIST patient-derived xenograft model possessing an exon 9 KIT mutation. These studies provide strong rationale for further use of AKT inhibition in combination with IM in primary GIST; however, alternative agents will need to be tested in combination with AKT inhibition in the resistant setting.

scholarly journals Synthesis and Biological Evaluation of New Antitubulin Agents Containing 2-(3′,4′,5′-trimethoxyanilino)-3,6-disubstituted-4,5,6,7-tetrahydrothieno[2,3-c]pyridine Scaffold

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1690
Author(s):  
Romeo Romagnoli ◽  
Filippo Prencipe ◽  
Paola Oliva ◽  
Barbara Cacciari ◽  
Jan Balzarini ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Cell Lines ◽  
Cancer Cell ◽  
Mononuclear Cells ◽  
Cancer Cell Lines ◽  
Biological Evaluation ◽  
Pyridine Derivative ◽  
Tubulin Polymerization ◽  
Dependent Manner

Two novel series of compounds based on the 4,5,6,7-tetrahydrothieno[2,3-c]pyridine and 4,5,6,7-tetrahydrobenzo[b]thiophene molecular skeleton, characterized by the presence of a 3′,4′,5′-trimethoxyanilino moiety and a cyano or an alkoxycarbonyl group at its 2- or 3-position, respectively, were designed, synthesized, and evaluated for antiproliferative activity on a panel of cancer cell lines and for selected highly active compounds, inhibition of tubulin polymerization, and cell cycle effects. We have identified the 2-(3′,4′,5′-trimethoxyanilino)-3-cyano-6-methoxycarbonyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine derivative 3a and its 6-ethoxycarbonyl homologue 3b as new antiproliferative agents that inhibit cancer cell growth with IC50 values ranging from 1.1 to 4.7 μM against a panel of three cancer cell lines. Their interaction with tubulin at micromolar levels leads to the accumulation of cells in the G2/M phase of the cell cycle and to an apoptotic cell death. The cell apoptosis study found that compounds 3a and 3b were very effective in the induction of apoptosis in a dose-dependent manner. These two derivatives did not induce cell death in normal human peripheral blood mononuclear cells, suggesting that they may be selective against cancer cells. Molecular docking studies confirmed that the inhibitory activity of these molecules on tubulin polymerization derived from binding to the colchicine site.

scholarly journals HSP90 Inhibitor, 17-DMAG, Alone and in Combination with Lapatinib Attenuates Acquired Lapatinib-Resistance in ER-positive, HER2-Overexpressing Breast Cancer Cell Line

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2630
Author(s):  
Hye Jin Lee ◽  
Seungho Shin ◽  
Jinho Kang ◽  
Ki-Cheol Han ◽  
Yeul Hong Kim ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Proliferation ◽  
Protein Expression ◽  
Cell Line ◽  
Cell Lines ◽  
Xenograft Model ◽  
Resistant Cell ◽  
Bt474 Cell ◽  
Hsp90 Inhibitors ◽  
Her2 Breast Cancer

Lapatinib, a Human Epidermal growth factor Receptor 2 (HER2)-targeting therapy in HER2-overexpressing breast cancer, has been widely used clinically, but the prognosis is still poor because most patients acquire resistance. Therefore, we investigated mechanisms related to lapatinib resistance to evaluate new therapeutic targets that may overcome resistance. Lapatinib-resistant cell lines were established using SKBR3 and BT474 cells. We evaluated cell viability and cell signal changes, gene expression and protein changes. In the xenograft mouse model, anti-tumor effects were evaluated using drugs. Analysis of the protein interaction network in two resistant cell lines with different lapatinib resistance mechanisms showed that HSP90 protein was commonly increased. When Heat Shock Protein 90 (HSP90) inhibitors were administered alone to both resistant cell lines, cell proliferation and protein expression were effectively inhibited. However, inhibition of cell proliferation and protein expression with a combination of lapatinib and HSP90 inhibitors showed a more synergistic effect in the LR-BT474 cell line than the LR-SKBR3 cell line, and the same result was exhibited with the xenograft model. These results suggest that HSP90 inhibitors in patients with lapatinib-resistant Estrogen Receptor (ER) (+) HER2 (+) breast cancer are promising therapeutics for future clinical trials.

Blocking of Cytokine Survival Signals along with Intense Bcr-Abl Kinase Inhibition May Eradicate CML Progenitor Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3250-3250
Author(s):  
Devendra K Hiwase ◽  
Deborah L White ◽  
Jason A Powell ◽  
Verity A Saunders ◽  
Stephanie Zrim ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Lines ◽  
Research Funding ◽  
Kinase Activity ◽  
Short Term ◽  
Kinase Inhibition ◽  
Gm Csf ◽  
Abl Kinase ◽  
Cd34 Cells ◽  
Short Term Culture

Abstract Abstract 3250 Poster Board III-1 Preclinical studies of imatinib set the paradigm of continuous Bcr-Abl kinase inhibition for optimal response in chronic myeloid leukemia (CML). However, the clinical success of once daily dasatinib, despite its short serum half life, implies that intermittent inhibition of Bcr-Abl kinase activity is sufficient for clinical response. In vitro studies also demonstrated that short-term intense (≥90%) Bcr-Abl kinase inhibition triggers cell death in BCR-ABL + cell lines, demonstrating their oncogene addiction. However, the effect of short-term intense kinase inhibition on CD34+ CML progenitors is not studied. Clinical, mathematical modelling and in vitro studies suggest that leukemic stem cells (LSC) are difficult to eradicate and hence the majority of CML patients may not be cured with tyrosine kinase inhibitors (TKI). Inadequate Bcr-Abl kinase inhibition has been postulated to cause refractoriness of LSC to TKI's. This may be due to increased expression of ABCB1 and ABCG2 efflux proteins, or the quiescent state of LSC. However, the phenomenon could be independent of Bcr-Abl kinase activity. In vivo leukemic progenitors live in a cytokine rich environment which may be providing a mechanism for Bcr-Abl independent resistance. We have assessed the impact of short-term intense Bcr-Abl kinase inhibition on CML cell lines and CML CD34+ primary cells in the presence and absence of cytokines. In CML cell lines, short-term (cells were cultured with dasatinib for 30 min and following thorough drug washout, cells were recultured in drug free media for 72 hr) intense Bcr-Abl kinase inhibition with 100 nM dasatinib triggers cell death. In CML-CD34+ cells 30 min of culture with 100 nM dasatinib (n=13) or 30 μM IM (n=7) reduced the level of p-Crkl (surrogate marker of Bcr-Abl kinase activity) by 97±3% and 96±4% respectively. In the presence of either a six growth factors cocktail (6-GF; n=10) or GM-CSF (n=11) or G-CSF (n=4) alone, despite 97% inhibition of p-Crkl, short-term culture with 100 nM dasatinib (D100ST) reduced colony forming cells (CFC) by only 24%, 32% or 5%, respectively. However without cytokines, D100ST reduced CML-CD34+ CFCs by 70%. Consistent with the results observed with dasatinib, short-term culture with 30 μM imatinib (IM) (n=3) also reduced 90% CFC in the absence of cytokines but by only 38% in the presence of 6-GF. These results suggest that in CML-CD34+ cells, GM-CSF, G-CSF or 6-GF mediate Bcr-Abl independent TKI resistance. It is possible that cytokines may be promoting cell survival via signalling pathways that are refractory to dasatinib. To examine this possibility, we assessed the effect of D100ST on p-STAT5 signalling in CML-CD34+ cells, in the presence and absence of GM-CSF, G-CSF or 6-GF. STAT5 was constitutively phosphorylated in CML-CD34+ cells, and in the absence of cytokines, D100ST reduced the p-STAT 5. STAT5 phosphorylation was not inhibited by D100ST when cells were cultured with 6-GFs or GM-CSF however, the combination of D100ST and a Janus kinase (Jak) inhibitor dramatically reduced p-STAT5. Similarly, in the presence of GM-CSF (32.35±5.16% vs. 68.33±14.90%) or G-CSF (58.13±13 vs. 94.68±21.12) combination of D100ST and JAK inhibitor significantly reduced CFC compared to D100ST only. Thus our data suggest that in contrast to CML cell lines, primary CML progenitors may not be completely dependent on the BCR-ABL oncogene and that activation of the cytokine mediated JAK-2/STAT-5 pathway may circumvent the need for BCR-ABL signalling for maintenance of survival. Thus a therapeutic strategy based on short-term intense kinase inhibition may have limited success unless critical redundant cytokine-induced survival pathways are also inhibited. We postulate that blockade of cytokine signalling along with short-term intense Bcr-Abl kinase inhibition with a potent second generation TKI may provide a novel strategy to eradicate primitive CML cells. Fig 1 In CML-CD34+ cells, Jak kinase inhibition abrogates the rescuing effect of cytokines on cell death induced by BCR-ABL blockade: In the absence of cytokines (No GF, n=11) short-term culture with 100 nM dasatinib (D100ST) reduced CFCs by 67% of control, however in the presence of 6-GFs (n=10), GM-CSF (n=10) or G-CSF (n=4) it could reduce CFCs by only 24%, 32% or 5% of control respectively (B) In the presence of GM-CSF (n= 4) or G-CSF (n= 4), combination of Jak inhibition and D100ST reduced CFC compared to dasatinib alone. Fig 1. In CML-CD34+ cells, Jak kinase inhibition abrogates the rescuing effect of cytokines on cell death induced by BCR-ABL blockade: In the absence of cytokines (No GF, n=11) short-term culture with 100 nM dasatinib (D100ST) reduced CFCs by 67% of control, however in the presence of 6-GFs (n=10), GM-CSF (n=10) or G-CSF (n=4) it could reduce CFCs by only 24%, 32% or 5% of control respectively (B) In the presence of GM-CSF (n= 4) or G-CSF (n= 4), combination of Jak inhibition and D100ST reduced CFC compared to dasatinib alone. Disclosures: White: Novartis and Britol-Myers Squibb: Research Funding. Hughes:BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

The Natural Product Borrelidin Induces UPR and Apoptosis in AML Cell Lines

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4260-4260
Author(s):  
Leah Jackson ◽  
Shelby Bechler ◽  
Justin Miller ◽  
Amy Brownell ◽  
Danielle Garshott ◽  
...  
Keyword(s):  
Cell Death ◽  
Er Stress ◽  
Natural Product ◽  
Cell Lines ◽  
Time Course ◽  
Conflicts Of Interest ◽  
Xenograft Model ◽  
Myelogenous Leukemia ◽  
Ic50 Values

Abstract Abstract 4260 Acute Myelogenous Leukemia (AML) is the most common form of leukemia. Current therapies are intense and even those fortunate enough to achieve remission often relapse extending extremely poor prognoses to these patient. The most commonly used therapeutics, namely cytarabine aribinoside, the anthracyclines and etoposide, are decades old and target ubiquitous cellular processes. We have previously reported that small molecules and natural products that activate and exacerbate the unfolded protein response (UPR) can effectively and selectively induce cell death in a wide variety of solid tumor cells. We hypothesized that the UPR might be a viable new therapeutic target in AML and sought to determine whether or not the novel UPR-inducing natural product borrelidin might be used as such an agent. A luminescent proliferation assay performed with panel of four AML cell lines treated with the ER stress-inducing antibiotic tunicamycin (Tm) revealed that three of the cell lines displayed IC50 values between 0.47–2.5μ M, doses of Tm which are known to induce a low to moderate level of ER stress. We then repeated the experiment with the more general UPR-inducing natural product borrelidin, which has been shown to have potent anti-inflammatory properties in several murine assays in vivo. All four cell lines were sensitive to borrelidin, displaying IC50 values between 0.032–0.29 μ M. Time course assays performed with borrelidin revealed 4–20 fold increases in active caspase 3 and 7 indicating borrelidin-induced AML decreases in cell proliferation might be the result of apoptosis. Quantitative reverse-transcription real time PCR performed with mRNA isolated from two AML cell lines revealed an increase in the UPR-related transcripts CHOP, ATF4, and GADD34 and the cell death genes Noxa, Puma, DR5 and Bim confirming that borrelidin could induce the UPR and apoptosis in AML cells. Studies currently underway in our laboratory will determine the ability of borrelidin and other UPR-inducing agents to reduce leukemic burden in an in vivo xenograft model. Disclosures: No relevant conflicts of interest to declare.

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