scholarly journals Dual targeting of FGFR3 and the ERBB receptor family or AXL enhances the efficacy of FGFR inhibitors in FGFR3 fusion-driven bladder cancer

2021 ◽  
Author(s):  
David Lau ◽  
Margeaux Hodgson-Garms ◽  
Austen Lavis ◽  
Ian Luk ◽  
Laura Jenkins ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Cell Viability ◽  
Cell Lines ◽  
Combination Treatment ◽  
Tyrosine Kinases ◽  
Cell Signalling ◽  
Acquired Resistance ◽  
Growth Factor Receptor ◽  
Concomitant Increase ◽  
Erbb Family

Abstract BackgroundMutations and fusions in Fibroblast Growth Factor Receptor 3 (FGFR3) occur in 10-20% of metastatic urothelial carcinomas, and can confer sensitivity to FGFR inhibitors such as BGJ398 and erdafitinib. However, responses to these agents are often short-lived due to the development of acquired resistance. The objective of this study was to identify mechanisms of acquired resistance to FGFR inhibitors in two previously uncharacterized bladder cancer cell lines harbouring FGFR3 fusions, and assess rational combination therapies to enhance their activity. MethodsAcquired resistance to FGFR inhibitors was generated in two FGFR3 fusion harbouring cell lines, SW780 (FGFR3-BAIAP2L1 fusion) and RT4 (FGFR3-TACC3 fusion), by either long-term exposure to increasing concentrations of BGJ398 or sustained exposure to high concentrations of drug. Alterations in levels of key cell signalling regulators was assessed in resistant lines by phospho-RTK arrays and immunoblotting. Synergy between BGJ398 and alternate targeted therapies was explored using cell viability and apoptosis assays.ResultsAcquired resistance to BGJ398 in SW780 and RT4 cells was associated with increased expression of members of ERBB family of receptor tyrosine kinases and pAXL. Combination treatment of resistant cells with an FGFR inhibitor and either a pan-ERBB or an AXL inhibitor overcame this resistance. We also noted rapid reactivation of pERK in parental FGFR3 fusion-driven lines within 4-72 hours of BGJ398 treatment, with concomitant increase in pERBB3. Up-front combination treatment with BGJ398 and the pan-ERBB inhibitor AZD8931 delayed the reactivation of pERK, and induced a synergistic inhibition of cell viability and a concomitant increase in apoptosis.ConclusionsWe identify increased activation of AXL and ERBB family receptors as mechanisms of resistance to FGFR inhibition. Our findings suggest that upfront combination treatment with FGFR and pan-ERBB inhibitors warrants further investigation for FGFR3-fusion harbouring bladder cancers.

scholarly journals Dual Targeting of FGFR3 and ERBB3 Enhances The Efficacy of FGFR Inhibitors in FGFR3 Fusion-Driven Bladder Cancer

2021 ◽  
Author(s):  
Andrew J Weickhardt ◽  
David K Lau ◽  
Margeaux Hodgson-Garms ◽  
Austen Lavis ◽  
Laura J Jenkins ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Cell Lines ◽  
Cancer Cell ◽  
Combination Treatment ◽  
Acquired Resistance ◽  
Cancer Cell Lines ◽  
Bladder Cancer Cell ◽  
Long Term Treatment ◽  
Inhibitor Treatment

Abstract Background Mutations and fusions in Fibroblast Growth Factor Receptor 3 (FGFR3) occur in 10-20% of metastatic urothelial carcinomas and confers sensitivity to FGFR inhibitors. However, responses to these agents are often short-lived due to the development of acquired resistance. The objective of this study was to identify mechanisms of resistance to FGFR inhibitors in two previously uncharacterised bladder cancer cell lines harbouring FGFR3 fusions and assess rational combination therapies to enhance sensitivity to these agents. Methods Acquired resistance to FGFR inhibitors was generated in two FGFR3 fusion harbouring cell lines, SW780 (FGFR3-BAIAP2L1 fusion) and RT4 (FGFR3-TACC3 fusion), by long-term exposure to the FGFR inhibitor BGJ398. Changes in levels of receptor tyrosine kinases were assessed by phospho-RTK arrays and immunoblotting. Changes in cell viability and proliferation were assessed by the Cell-Titre Glo assay and by propidium iodide staining and FACS analysis. Results Long term treatment of FGFR3-fusion harbouring SW780 and RT4 bladder cancer cell lines with the BGJ398 resulted in the establishment of resistant clones. These clones were cross-resistant to the clinically approved FGFR inhibitor erdafitinib and the covalently binding irreversible FGFR inhibitor TAS-120, but remained sensitive to the MEK inhibitor trametinib, indicating resistance is mediated by alternate activation of MAPK signalling. The FGFR inhibitor-resistant SW780 and RT4 lines displayed increased expression of pERBB3, and strikingly, combination treatment with an FGFR inhibitor and the ATP-competitive pan-ERBB inhibitor AZD8931 overcame this resistance. Notably, rapid induction of pERBB3 and reactivation of pERK also occurred in parental FGFR3 fusion-driven lines within 24 hours of FGFR inhibitor treatment, and combination treatment with an FGFR inhibitor and AZD8931 delayed the reactivation of pERBB3 and pERK and synergistically inhibited cell proliferation. Conclusions We demonstrate that increased expression of pERBB3 is a key mechanism of adaptive resistance to FGFR inhibitors in FGFR3-fusion driven bladder cancers, and that this also occurs rapidly following FGFR inhibitor treatment. Our findings demonstrate that resistance can be overcome by combination treatment with a pan-ERBB inhibitor and suggest that upfront combination treatment with FGFR and pan-ERBB inhibitors warrants further investigation for FGFR3-fusion harbouring bladder cancers.

scholarly journals Efficacy of the CDK4/6 Dual Inhibitor Abemaciclib in EGFR-Mutated NSCLC Cell Lines with Different Resistance Mechanisms to Osimertinib

Cancers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 6
Author(s):  
Silvia La Monica ◽  
Claudia Fumarola ◽  
Daniele Cretella ◽  
Mara Bonelli ◽  
Roberta Minari ◽  
...  
Keyword(s):  
Cell Lines ◽  
Kinase Inhibitor ◽  
Acquired Resistance ◽  
Growth Factor Receptor ◽  
Resistance Mechanisms ◽  
Resistant Cell ◽  
Nsclc Cell ◽  
Dual Inhibitor ◽  
Nsclc Patients ◽  
Egfr Mutated

Abemaciclib is an inhibitor of cyclin-dependent kinases (CDK) 4 and 6 that inhibits the transition from the G1 to the S phase of the cell cycle by blocking downstream CDK4/6-mediated phosphorylation of Rb. The effects of abemaciclib alone or combined with the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib were examined in a panel of PC9 and HCC827 osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines carrying EGFR-dependent or -independent mechanisms of intrinsic or acquired resistance. Differently from sensitive cells, all the resistant cell lines analyzed maintained p-Rb, which may be considered as a biomarker of osimertinib resistance and a potential target for therapeutic intervention. In these models, abemaciclib inhibited cell growth, spheroid formation, colony formation, and induced senescence, and its efficacy was not enhanced in the presence of osimertinib. Interestingly, in osimertinib sensitive PC9, PC9T790M, and H1975 cells the combination of abemaciclib with osimertinib significantly inhibited the onset of resistance in long-term experiments. Our findings provide a preclinical support for using abemaciclib to treat resistance in EGFR mutated NSCLC patients progressed to osimertinib either as single treatment or combined with osimertinib, and suggest the combination of osimertinib with abemaciclib as a potential approach to prevent or delay osimertinib resistance in first-line treatment.

scholarly journals Transcriptome of Two Canine Prostate Cancer Cells Treated With Toceranib Phosphate Reveals Distinct Antitumor Profiles Associated With the PDGFR Pathway

2020 ◽  
Vol 7 ◽  
Author(s):  
Priscila E. Kobayashi ◽  
Patrícia F. Lainetti ◽  
Antonio F. Leis-Filho ◽  
Flávia K. Delella ◽  
Marcio Carvalho ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Growth Factor ◽  
Protein Expression ◽  
Cell Line ◽  
Cell Lines ◽  
Protein Interactions ◽  
Tyrosine Kinases ◽  
Growth Factor Receptor ◽  
Dependent Manner ◽  
Upregulated Genes

Canine prostate cancer (PC) presents a poor antitumor response, usually late diagnosis and prognosis. Toceranib phosphate (TP) is a nonspecific inhibitor of receptor tyrosine kinases (RTKs), including vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and c-KIT. This study aimed to evaluate VEGFR2, PDGFR-β, and c-KIT protein expression in two established canine PC cell lines (PC1 and PC2) and the transcriptome profile of the cells after treatment with TP. Immunofluorescence (IF) analysis revealed VEGFR2 and PDGFR-β protein expression and the absence of c-KIT protein expression in both cell lines. After TP treatment, only the viability of PC1 cells decreased in a dose-dependent manner. Transcriptome and enrichment analyses of treated PC1 cells revealed 181 upregulated genes, which were related to decreased angiogenesis and cell proliferation. In addition, we found upregulated PDGFR-A, PDGFR-β, and PDGF-D expression in PC1 cells, and the upregulation of PDGFR-β was also observed in treated PC1 cells by qPCR. PC2 cells had fewer protein-protein interactions (PPIs), with 18 upregulated and 22 downregulated genes; the upregulated genes were involved in the regulation of parallel pathways and mechanisms related to proliferation, which could be associated with the resistance observed after treatment. The canine PC1 cell line but not the PC2 cell line showed decreased viability after treatment with TP, although both cell lines expressed PDGFR and VEGFR receptors. Further studies could explain the mechanism of resistance in PC2 cells and provide a basis for personalized treatment for dogs with PC.

Antileukemic Activity of the HSP70 Inhibitor Pifithrin-μ

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3306-3306
Author(s):  
Martin Kaiser ◽  
Andrea Kuehnl ◽  
Jutta Ortiz-Tanchez ◽  
Ouidad Benlasfer ◽  
Cornelia Schlee ◽  
...  
Keyword(s):  
Cell Viability ◽  
Cell Lines ◽  
Combination Treatment ◽  
Caspase 3 ◽  
Lymphoblastic Leukemia ◽  
Active Form ◽  
Combination Therapies ◽  
Acute Leukemias ◽  
Genetic Characteristics ◽  
B Lineage

Abstract Abstract 3306 Introduction: Heat shock protein (HSP) 70 is aberrantly expressed in acute leukemias and other hematologic and solid malignancies, promoting tumor cell survival and therapy resistance. Recently, the small molecule pifithrin-μ (2-phenylethynesulfonamide) has been identified as a direct inhibitor of inducible HSP70, showing antiproliferative activity in different cell lines of solid tumors. Here, we analysed the in vitro antileukemic effect of pifithrin-μ in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) cell lines, as well as in primary AML blasts. In addition, incubations of pifithrin-μ with cytarabine, the histone deacetylase inhibitor SAHA, the HSP90 inhibitor 17-AAG, and the multikinase inhibitor sorafenib were performed to evaluate the potential use of combination therapies with pifithrin-μ in acute leukemias. Methods: Leukemic cell lines KG-1a (AML), K562 (CML in blast crisis), K562r (cytarabine-resistant K562), NALM-6 (B-lineage ALL), TOM-1 (B-lineage ALL, BCR-ABL pos.), Jurkat (T-lineage ALL), BE-13 (T-lineage ALL) and 9 bone marrow cell samples from newly diagnosed or relapsed AML patients were exposed to pifithrin-μ. Cell viability of all cell lines listed above was quantified by WST-1 assay. Subsequent functional analyses were performed on KG-1a and NALM-6 cells. Apoptosis was determined by annexin-V/7-AAD staining and subsequent flow cytometric analysis. Activated caspase-3 was detected by flow cytometry. Levels of the cell signaling kinase Akt were measured by intracellular staining and FACS analysis. Coincubations of pifithrin-μ with cytarabine, SAHA, 17-AAG or sorafenib were performed in KG-1a, NALM-6 and TOM-1, using WST-1 assays to analyse cytotoxic effects of combination therapies. Results: Pifithrin-μ at low micromolar concentrantions significantly inhibited viability of all acute leukemia cell lines tested, with IC50 values ranging from 2.5 to 12.7 μM independent of the differentiation lineage. Importantly, viability of both cytarabine-sensitive and -resistant K562 cells was effectively inhibited by pifithrin-μ. The median IC50 of primary AML blasts was 8.8 μM, ranging from 5.7 to 11.8 μM with no obvious differences regarding patients' clinical or genetic characteristics. Apoptosis was induced in a time- and dose-dependent fashion with a rate of specific apoptosis of 46% at 4 μM pifithrin-μ for NALM-6 and 36% at 40 μM pifithrin-μ for KG1a. In NALM-6, treatment with 3 μM pifithrin-μ for 24 hours resulted in a significant increase in the cleaved, active form of caspase-3, whereas in KG1a no increase in active caspase-3 was detected. Intracellular concentrations of Akt were markedly reduced after 12 hours incubation of NALM-6 with pifithrin-μ. In NALM-6, KG-1a, and TOM-1 combination treatment of pifithrin-μ at concentrations below the IC50 with either SAHA, 17-AAG or sorafenib resulted in a significant decrease of cell viability compared to corresponding monotherapy. Thus in NALM-6 combination of 2 μM pifithrin-μ with 0.6 μM SAHA inhibited viability by 73%, compared to 22% and 0% inhibition for either drug alone (p<0.05). Combination of 2 μM pifithrin-μ with 2 μM 17-AAG led to 58% inhibition, in contrast the monotherapy inhibited cell viability only in 31% for either drug alone. In NALM-6 and TOM-1, the combination of pifithrin-μ with cytarabine decreased viability significantly (47% and 55%, respectively), whereas the single agents were less effective (22% for 2 μM pifithrin-μ, 24% for 9 nM cytarabine in NALM-6; 26% for 3.5 μM pifithrin-μ and 41% for 40 nM cytarabine in TOM-1). Conclusion: This is, to our knowledge, the first report of the antileukemic effects of the HSP70 inhibitor pifithrin-μ. The inhibitor is highly active against all AML and ALL cell lines tested, including cytarabine resistant cell lines as well as primary leukemic cells. Effectivity of pifithrin-μ could even be increased in combination treatment with other antileukemic agents. Targeting HSP70 might be a promising new therapeutic approach for the treatment of acute leukemias to overcome drug resistance. Thus, our data might build a framework for future clinical trials. Disclosures: No relevant conflicts of interest to declare.

Compensatory Signaling From ROR1 and the Pre-B Cell Receptor Promote Survival of t(1;19) Acute Lymphoblastic Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2466-2466
Author(s):  
Vincent T Bicocca ◽  
Bill H Chang ◽  
Markus Muschen ◽  
Brian J. Druker ◽  
Jeffrey W Tyner
Keyword(s):  
Cell Viability ◽  
B Cell ◽  
Signaling Pathways ◽  
Cell Lines ◽  
Tyrosine Kinases ◽  
Kinase Inhibitor ◽  
Lymphoblastic Leukemia ◽  
Immunoblot Analysis ◽  
Cell Receptor ◽  
Cell Surface Receptor

Abstract Abstract 2466 BACKGROUND: Aberrant tyrosine kinase activity is commonly implicated in the pathogenesis of leukemia and other cancers. Identification of these leukemogenic tyrosine kinases has proven invaluable for diagnostic and prognostic stratification of patients as well as for the development of novel strategies for therapeutic intervention. We previously demonstrated that siRNA screening of mononuclear cells from leukemia patients can determine sensitivity to individual tyrosine kinases. With the goal of uncovering novel viability-dependent tyrosine kinases in leukemia patients, we have employed an RNAi-assisted protein target identification (RAPID) assay to screen cytogenetic subtypes of acute lymphoblastic leukemia (ALL). ALL is the most common pediatric cancer, accounting for one-quarter of all childhood malignancies. Childhood ALL has a primarily B cell precursor phenotype and is characterized by chromosomal abnormalities, primarily translocations and duplications. One of the most common recurring translocations associated with pediatric ALL, t(1;19)(q23;p13.3), generates the E2A-PBX1 fusion product. Here we show unique viability-dependent expression of a receptor tyrosine kinase, ROR1, in the t(1;19) ALL background. In addition, we identify a kinase inhibitor, dasatinib, with significant activity against t(1;19) ALL cells due to its capacity to inhibit tyrosine kinases necessary for transduction of pre-B cell receptor (preBCR) signaling. Finally, we show that ROR1 and the preBCR activate mutually compensatory signaling pathways, suggesting that optimal therapeutic regimens would include agents targeting both pathways. METHODS: To identify targets required for viability of leukemic cells, we screened cell lines as well as primary cells from ALL patients with siRNAs and determined cell viability using an MTS assay. ROR1 expression levels were determined by RT-PCR, immunoblot analysis and flow cytometry. Kinase inhibitor screening was performed on both cells lines and primary ALL cells by treating samples with a library of small-molecule inhibitors and cell viability was assessed by MTS. Signaling pathways disrupted by inhibitor treatment or ROR1 knockdown were interrogated by phospho-protein arrays and confirmed by immunoblot analysis. RESULTS: The RAPID assay identified a unique sensitivity to the cell surface receptor ROR1 in a subject identified with t(1;19) pediatric ALL. Similar sensitivity was not observed in ALL patients of alternative cytogenetic subtypes. Examination of additional ALL patient samples revealed conserved overexpression of the ROR1 transcript in t(1;19)-positive specimens with absence of ROR1 expression in t(1;19)-negative samples. Cell lines and early passage xenograft cells confirmed overexpression and functional dependence of t(1;19)-positive cells on ROR1. A subsequent kinase inhibitor screen of t(1;19) ALL cell lines and patient samples revealed universal sensitivity to the FDA-approved drug dasatinib. Further examination revealed the dasatinib targets, BTK and LYN, which signal downstream of the preBCR as the viability dependent targets of dasatinib in t(1;19) ALL. Inhibition of the preBCR results in transient loss of AKT activity and, surprisingly, upregulation of ROR1. Analysis of signaling pathways after silencing of ROR1 or dasatinib treatment revealed compensatory signaling pathways emanating from ROR1 and the preBCR that both serve to regulate AKT activity. Consequently, combination of ROR1 knockdown and dasatinib treatment resulted in additive impairment of cell viability compared with either treatment alone. CONCLUSION: The cell surface receptor ROR1 is consistently overexpressed in t(1;19) ALL. RNAi mediated downregulation of ROR1 impairs the viability of these cells. Similarly, t(1;19) cells are sensitive to the kinase inhibitor dasatinib due to activity against the preBCR. Combined targeting of ROR1 and the preBCR with dasatinib yields an additive viability effect due to compensatory signaling pathways aimed at regulating AKT. These results demonstrate a novel mechanism of AKT regulation in t(1;19) ALL as well as a therapeutic strategy for treatment of t(1;19) ALL. Disclosures: Druker: MolecularMD: Equity Ownership, OHSU and Dr. Druker have a financial interest in MolecularMD. Technology used in this research has been licensed to MolecularMD. This potential conflict of interest has been reviewed and managed by the OHSU Conflict of Interest in Research Committee and t; Ariad Pharmaceuticals: Consultancy; OHSU patent #843: Mutated ABL Kinase Domains: Patents & Royalties; Bristol-Myers Squibb: OHSU has clinical trial contracts with Bristol-Myers-Squibb to pay for patient costs, nurse and data manager salaries, and institutional overhead. Dr. Druker does not derive salary, nor does his lab receive funds from these contracts.; Novartis: OHSU has clinical trial contracts with Novartis to pay for patient costs, nurse and data manager salaries, and institutional overhead. Dr. Druker does not derive salary, nor does his lab receive funds from these contracts.; Cylene: Consultancy.

Identification of head and neck cancers (SCCHN) that may respond to dual inhibition of EGFR and HER3 signaling.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 5575-5575
Author(s):  
David S. Shames ◽  
Howard Stern ◽  
Kim Walter ◽  
Brittany Jiang ◽  
Ling Fu ◽  
...  
Keyword(s):  
Cell Lines ◽  
Tyrosine Kinases ◽  
Growth Factor Receptor ◽  
Bimodal Distribution ◽  
Autocrine Signaling ◽  
Oncogenic Signaling ◽  
Epithelial Cancers ◽  
Formalin Fixed Paraffin Embedded ◽  
Dual Action ◽  
High Level

5575 Background: Oncogenic signaling through the epidermal growth factor receptor family is one of the most frequent alterations found in human epithelial cancers. These receptor tyrosine kinases mediate their effects via high-level co-expression and homo- and heterodimerization events that drive tumor growth, metastasis, and survival. Extensive preclinical studies suggested that some cell lines depend on oncogenic autocrine signaling through HER3 (Wilson et al.). This phenotype was particularly prominent in cell lines derived from SCCHN and was strongly correlated with high HRG expression. Interestingly, two patients with SCCHN tumors that expressed high levels of HRG in our phase Ia trial (abstract #95245) of MEHD7954A, a dual-action human IgG1 antibody that blocks ligand binding to EGFR and HER3 (Schaefer et al.) had partial responses. To further explore the hypothesis that high-level HRG expression defines a sub-population of SCCHN that may be sensitive to agents targeting HER3, and to identify other potential target indications for the development of MEHD7954A, we evaluated the expression of HRG in large cohorts of multiple solid tumor indications. Methods: HER3 and HRG expression was analyzed by qRT-PCR in 648 formalin-fixed paraffin embedded primary tumor samples from patients with NSCLC, SCCHN, melanoma, CRC and triple-negative breast cancer. Results: SCCHN-derived tumor samples had the highest levels of HRG expression, exhibiting a bimodal distribution in SCCHN – a pattern that is clearly distinct when compared to other tumor types. These data suggest that high HRG levels and potentially HER3-dependent autocrine signaling occur more frequently in SCCHN than in other tumors. Further we investigated whether overexpression of HRG in SCCHN correlated with stage and disease outcome. Updated results from these extended studies will be presented. Conclusions: SCCHN tumors exhibit bimodal expression of HRG, suggesting that HRG expression levels may be useful in identifying a subset of patients most likely to benefit from inhibition of HER3 activity. Antitumor activity in such patients has been observed in a phase I study of MEHD7954A (abstract #95245).

scholarly journals TRPM2-AS promotes bladder cancer-genesis by targeting miR-22-3p thus releasing GINS2 mRNA

2020 ◽  
Author(s):  
Yudong Tian ◽  
Yanbin Guan ◽  
Yang Su ◽  
Tao Yang ◽  
Haizhou Yu
Keyword(s):  
Bladder Cancer ◽  
Cell Viability ◽  
Cell Lines ◽  
Cancer Cell ◽  
Tumor Promoter ◽  
Luciferase Reporter ◽  
Downstream Target ◽  
Bioinformatic Tools ◽  
Direct Binding ◽  
Cell Phenotypes

Abstract Background: We aimed to study the effects of lncRNA TRPM2-AS in bladder cancer (BLCA) by interacting with its downstream effectors miR-22-3p and GINS2 mRNA.Methods: Online bioinformatic tools were used to identify the key lncRNA, miRNA and mRNA of interest in BLCA. TRPM2-AS, miR-22-3p and GINS2 mRNA expression was measured by qRT-PCR in bladder tissues and selected cell lines. Subcellular localization of TRPM2-AS in T24 and 5637 cell lines was identified using a cellular fractionation method. Luciferase reporter assay, RIP assay and RNA pull-down assay were employed to validate the direct binding relationship between TRPM2-AS, miR-22-3p and GINS2 mRNA. Cell viability, proliferation and apoptosis were measured by a series of cell functional experiments in T24 and 5637 cells.Results: TRPM2-AS was primarily located in cell cytoplasm and significantly up-regulated in BLCA tissues and cell lines. TRPM2-AS knockdown significantly inhibited cell viability and proliferation, but promoted cell apoptosis. miR-22-3p, a significant downstream target of TRPM2-AS, showed a lower expression level in BLCA tissues and cell lines. miR-22-3p inhibition resulted in a significant enhancement of BLCA cancer cell phenotypes. Lastly, GINS2 mRNA was a downstream target of miR-22-3p, and was significantly up-regulated in BLCA. The knockdown of GINS2 led to a significant suppression of BLCA cancer cell phenotypes.Conclusions: TRPM2-AS was a tumor promoter and fulfilling its role through binding to miR-22-3p to increase GINS2 expression. This novel interactome in BLCA might become a new therapy in BLCA.

Evaluation of a novel irreversible pan-HER inhibitor in bladder cancer models.

2013 ◽  
Vol 31 (6_suppl) ◽  
pp. 253-253
Author(s):  
Petros Grivas ◽  
Andreas Karatsinides ◽  
Kathleen C. Day ◽  
Priya Kunju ◽  
Alyssa Paul ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Bladder Cancer ◽  
Cell Viability ◽  
Cell Lines ◽  
Cancer Cell ◽  
Cancer Cell Lines ◽  
Bladder Cancer Cell ◽  
Phase Iii ◽  
Cytostatic Effect ◽  
Cancer Models

253 Background: Human epidermal receptors (HER) are overexpressed and HER signaling is biologically relevant in bladder cancer and may mediate chemotherapy resistance. Dacomitinib is a novel, potent, irreversible pan-HER inhibitor with activity against several solid tumors, currently in a phase III clinical trial in NSCLC. We hypothesized that dacomitinib has antitumor activity in bladder cancer models. Methods: Expression level of EGFR and HER2 protein was measured semi-quantitatively in 8 bladder cancer cell lines. We treated UM-UC-3, UM-UC-6, UM-UC-9 cell lines with dacomitinib (1nM-10uM) for 24-72 hours, and measured cell viability, proliferation, apoptosis, and cell cycle effects. Correlations between dose and cell viability were measured by two-way ANOVA (GraphPad Prism 5.0). We injected age-matched male NOD/SCID mice SC with 1x106 UM-UC-6 and UM-UC-9 cells, respectively, generating xenografts. Mice were randomized and treated with dacomitinib, 6mg/kg p.o. daily, starting 1 day or 1 week after cell injection; controls were treated with vehicle. Mice were monitored daily, weighed weekly, sacrificed at 4 weeks and tumors weighed. Results: In vitro, significant cytostatic effect was noted with as low as 50nM in UM-UC6 cells and 100nM in UM-UC9 cells. UM-UC3 cells did not exhibit cytostatic effect even with 1000nM, corresponding to differential target protein (HER) expression. Dacomitinib (2uM) induced apoptosis (UM-UC-6), and G1 cell cycle arrest in both cell lines. These effects corresponded to dacomitinib-mediated inhibition of EGFR, ERK, AKT phosphorylation. In vivo, xenograft weights in both cell lines were significantly lower in dacomitinib-treated mice vs control (p<0.001), corresponding to pharmacodynamic effects (decreased E-cadherin, p-EGFR, p-ERK, mitotic count). Dacomitinib 6mg/kg p.o. daily resulted in significantly lower tumor weights vs lapatinib 50 mg/kg p.o. daily in UM-UC-9 xenograft model (p=0.0052). Conclusions: Dacomitinib demonstrated single-agent activity in bladder cancer cell lines and xenografts. Induction of apoptosis and G1 phase arrest are the suggested mechanisms for anti-tumor activity. Further investigation of this inhibitor in bladder cancer models is being pursued.

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