Dual AKT inhibition with perifosine and GCP enhances apoptosis in prostate cancer: Clinical implications

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 14096-14096
Author(s):  
R. L. Vinall ◽  
K. Hwa ◽  
C. Pan ◽  
P. Ghosh ◽  
P. N. Lara ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Western Blot ◽  
Cell Lines ◽  
Combination Treatment ◽  
Flow Cytometric Analysis ◽  
Fold Increase ◽  
Parp Cleavage ◽  
Clonogenic Potential ◽  
Ic50 Values ◽  
Induced Apoptosis

14096 Background: Genistein combined polysaccharide (GCP) has been shown to exhibit anti-cancer properties in both experimental and clinical models of prostate cancer (CaP). Perifosine is an alkylphospholipid with clinical anti-neoplastic activity. Both agents inhibit the AKT signaling pathway. Methods: Prostate cancer cell lines (LNCaP, LNCaP stably transfected with R273H or P151S p53 mutant allele, cds1, and PC3) were treated with GCP, perifosine, or both. IC50 values were established using the MTT assay. Apoptosis was assessed by flow cytometry, Western blot of PARP cleavage, and caspase activity. Clonogenic potential was assessed by colony assay. Status of AKT, p53, p21, AR and PSA was determined by Western blot. All experiments were performed in triplicate. Results: Perifosine inhibited AKT activity in all the cell lines. GCP had little or no effect on AKT activity but reduced AR and PSA levels. The combination of GCP and perifosine further increased the level of AKT inhibition and maintained inhibition for longer when compared to treatment with perifosine alone. Flow cytometric analysis of LNCaP revealed that combination treatment dramatically increased SubG1 levels (23-fold increase versus a 4.4-fold increase for GCP alone and a 6.5% increase for perifosine alone). Apoptosis was confirmed by PARP and caspase analysis. As single agents, the main effect of GCP or perifosine was to induce growth arrest as shown by a decrease in S-phase and increased p21. The cds1 cell line responded similarly to LNCaP, however, cell lines that expressed mutant p53 or were p53 null were not susceptible to GCP/perifosine-induced apoptosis. Combination treatment further decreased the clonogenic potential in all of the cell lines assessed when compared to treatment with the single agents alone. Conclusions: Treatment with a combination of the AKT inhibitors GCP and perifosine dramatically increases apoptosis and/or inhibits clonogenic potential in several CaP cell lines. The effect of the combination treatment on apoptosis appears to be dependent on p53 status. Clinical validation of these findings is warranted. A clinical trial of hormone therapy with or without GCP/perifosine is presently in development. No significant financial relationships to disclose.

scholarly journals Antiproliferative Efficacy of N-(3-chloro-4-fluorophenyl)-6,7-dimethoxyquinazolin-4-amine, DW-8, in Colon Cancer Cells Is Mediated by Intrinsic Apoptosis

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4417
Author(s):  
Rabin Neupane ◽  
Saloni Malla ◽  
Mariam Sami Abou-Dahech ◽  
Swapnaa Balaji ◽  
Shikha Kumari ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Colon Cancer ◽  
Cancer Cells ◽  
Cell Lines ◽  
Colon Cancer Cells ◽  
Apoptotic Pathway ◽  
Anticancer Efficacy ◽  
Colon Cell ◽  
Ic50 Values ◽  
Induced Apoptosis

A novel series of 4-anilinoquinazoline analogues, DW (1–10), were evaluated for anticancer efficacy in human breast cancer (BT-20) and human colorectal cancer (CRC) cell lines (HCT116, HT29, and SW620). The compound, DW-8, had the highest anticancer efficacy and selectivity in the colorectal cancer cell lines, HCT116, HT29, and SW620, with IC50 values of 8.50 ± 2.53 µM, 5.80 ± 0.92 µM, and 6.15 ± 0.37 µM, respectively, compared to the non-cancerous colon cell line, CRL1459, with an IC50 of 14.05 ± 0.37 µM. The selectivity index of DW-8 was >2-fold in colon cancer cells incubated with vehicle. We further determined the mechanisms of cell death induced by DW-8 in SW620 CRC cancer cells. DW-8 (10 and 30 µM) induced apoptosis by (1) producing cell cycle arrest at the G2 phase; (2) activating the intrinsic apoptotic pathway, as indicated by the activation of caspase-9 and the executioner caspases-3 and 7; (3) nuclear fragmentation and (4) increasing the levels of reactive oxygen species (ROS). Overall, our results suggest that DW-8 may represent a suitable lead for developing novel compounds to treat CRC.

scholarly journals The Effect of Fatty Acids on Ciprofloxacin Cytotoxic Activity in Prostate Cancer Cell Lines. Does Lipid Component Enhance Anticancer Ciprofloxacin Potential?

Cancers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 409
Author(s):  
Alicja Chrzanowska ◽  
Wioletta Olejarz ◽  
Grażyna Kubiak-Tomaszewska ◽  
Andrzej K. Ciechanowicz ◽  
Marta Struga
Keyword(s):  
Prostate Cancer ◽  
Fatty Acids ◽  
Cell Lines ◽  
Cancer Cell ◽  
Cytotoxic Effect ◽  
Cancer Cell Lines ◽  
Lncap Cells ◽  
Ic50 Values ◽  
Late Apoptosis ◽  
Pc3 Cells

Purpose: To assess cytotoxic effect of ciprofloxacin conjugates with fatty acids on prostate cancer cells (LNCaP and DU-145) with different hormone sensitivity, based on previous promising results from the PC3 cells. Methods: Cytotoxicity were estimated using MTT and LDH tests, whereas its mechanisms were estimated by apoptosis and IL-6 assays. The intensity of proteins involved in lipid metabolism was determined using ML-CS assay. Results: The hormone insensitive DU-145 cells were more vulnerable than the hormone sensitive LNCaP cells. The IC50 values for oleic (4), elaidic (5) and docosahexaenoic acid (8) conjugates were 20.2 µM, 17.8 µM and 16.5 µM, respectively, in DU-145 cells, whereas in LNCaP cells IC50 exceeded 20 µM. The strong conjugate cytotoxicity was confirmed in the LDH test, the highest (70.8%) for compound (5) and 64.2% for compound (8) in DU-145 cells. This effect was weaker for LNCaP cells (around 60%). The cytotoxic effect of unconjugated ciprofloxacin and fatty acids was weaker. The early apoptosis was predominant in LNCaP while in DU-145 cells both early and late apoptosis was induced. The tested conjugates decreased IL-6 release in both cancer cell lines by almost 50%. Proteomic analysis indicated influence of the ciprofloxacin conjugates on lipid metabolic proteins in prostatic cancer. Conclusion: Our findings suggested the cytotoxic potential of ciprofloxacin conjugates with reduction in proteins involved in prostate cancer progress.

scholarly journals miR-128 Targets the SIRT1/ROS/DR5 Pathway to Sensitize Colorectal Cancer to TRAIL-Induced Apoptosis

2018 ◽  
Vol 49 (6) ◽  
pp. 2151-2162 ◽  
Author(s):  
Bo Lian ◽  
Dongxiang Yang ◽  
Yanlong Liu ◽  
Gang Shi ◽  
Jibin Li ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Flow Cytometry ◽  
Western Blot ◽  
Cancer Cells ◽  
Cell Lines ◽  
Sirtuin 1 ◽  
Luciferase Reporter ◽  
Pcr Analysis ◽  
Reporter Assays ◽  
Induced Apoptosis

Background/Aims: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an ideal anti-tumor drug because it exhibits selective cytotoxicity against cancer cells. However, certain cancer cells are resistant to TRAIL, and the potential mechanisms are still unclear. The aim of this study was to reduce the resistance of colorectal cancer (CRC) cells to TRAIL. Methods: Quantitative real-time PCR analysis was performed to detect the expression of microRNA-128 (miR-128) in tissues from patients with CRC and CRC cell lines. MTT assays were used to evaluate the effect of miR-128 on TRAIL-induced cytotoxicity against CRC cell lines. The distribution of death receptor 5 (DR5) and the production of reactive oxygen species (ROS) were detected by flow cytometry analysis. Western blot, flow cytometry, and luciferase reporter assays were performed to evaluate the potential mechanism and pathway of miR-128-promoted apoptosis in TRAIL-treated CRC cells. Results: MiR-128 expression was downregulated in tumor tissues from patients with CRC as well as in CRC cell lines in vitro. The enforced expression of miR-128 sensitized CRC cells to TRAIL-induced cytotoxicity by inducing apoptosis. Mechanistically, bioinformatics, western blot analysis, and luciferase reporter assays showed that miR-128 directly targeted sirtuin 1 (SIRT1) in CRC cells. miR-128 overexpression suppressed SIRT1 expression, which promoted the production of ROS in TRAIL-treated CRC cells. This increase of ROS subsequently induced DR5 expression, and thus increased TRAIL-induced apoptosis in CRC cells. Conclusion: The combination of miR-128 with TRAIL may represent a novel approach for the treatment of CRC.

MicroRNA-126 attenuates cell apoptosis by targeting TRAF7 in acute myeloid leukemia cells

2018 ◽  
Vol 96 (6) ◽  
pp. 840-846 ◽  
Author(s):  
Qian Ding ◽  
Qing Wang ◽  
Yi Ren ◽  
Hong Qian Zhu ◽  
ZhuYun Huang
Keyword(s):  
Acute Myeloid Leukemia ◽  
Western Blot ◽  
Cell Lines ◽  
Cell Apoptosis ◽  
Myeloid Leukemia ◽  
Flow Cytometric Analysis ◽  
Tumor Necrosis Factor Receptor ◽  
Luciferase Assay ◽  
Acute Myeloid Leukemia Cells ◽  
Acute Myeloid

Acute myeloid leukemia (AML) has a 5-year survival rate of only about 30%–40% due to the self-renewal and differentiation ability of leukemia stem-like cells (LSCs). To address the potential for novel therapeutic targets in LSCs, we investigated the roles of miRNA-126 and tumor necrosis factor receptor-associated factor 7 (TRAF7) in AML. We used qRT-PCR and Western blot to investigate the expression levels of miRNA-126 and TRAF7 in AML cell lines. Then, we uncovered the effect of miRNA-126 on AML cell proliferation and apoptosis by MTT assay and flow cytometric analysis, respectively. Furthermore, dual-luciferase assay and Western blot were used to determine the target of miRNA-126 in AML and the potential mechanism by which cell apoptosis is suppressed by miRNA-126. We found that miRNA-126 was highly expressed in all of the AML cell lines, and that inhibition of miRNA-126 significantly induced cell death through apoptosis. The suppression of apoptosis in AML with high expression of miRNA-126 was caused by down-regulating TRAF7, which blocked the c-FLIP pathway. The role of miRNA-126 in AML makes it a potential therapeutic target to improve clinical outcomes for patients with AML.

Induction of G1 Arrest and Apoptosis in a Conditional Expression Model of AML1/ETO: P53-Independent Upregulation of P21/WAF/CIP1.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2576-2576
Author(s):  
Tobias Berg ◽  
Manfred Fliegauf ◽  
Jurij Pitako ◽  
Jan Burger ◽  
Mahmoud Abdelkarim ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Western Blot ◽  
Cell Lines ◽  
Blot Analysis ◽  
Parp Cleavage ◽  
G1 Arrest ◽  
U937 Cells ◽  
Negative Cell ◽  
Conditional Expression

Abstract Background: The translocation (8;21) is the most common chromosomal rearrangement in AML, resulting in the expression of the fusion protein AML1/ETO. We have developed an ecdysone-inducible U937 model, in which AML1/ETO is expressed in response to treatment with Ponasterone (Pon) A (Fliegauf et al, Oncogene 2004). This model system was used to determine the cellular effects of AML1/ETO and to identify its target genes in U937 cells. Methods: Effects of AML1/ETO expression upon cell growth, viability, cell cycle and apoptosis were analyzed by trypan blue exclusion, FACS analysis using propidium iodide and DiOC6 staining, DNA laddering and Western blot for PARP cleavage, respectively. The gene expression profile of U937 with and without conditional AML1/ETO expression was assessed using Affymetrix U133A microarrays. Wild-type U937 cells with and without PonA treatment as well as AML1/ETO-negative and AML1/ETO-positive myeloid cell lines served as controls. Northern and Western Blotting were used for validation of expression changes. Results: Induction of AML1/ETO expression in U937 resulted in reduced cell growth, G1 arrest and in apoptosis beginning 48–72 hours after PonA treatment. To investigate the underlying mechanisms, microarray analysis was performed. Expression profiles of AML1/ETO-positive and AML1/ETO-negative cell lines formed distinct clusters. Based on stringent criteria, 191 different genes were found upregulated, whereas 37 were downregulated upon expression of AML1/ETO in U937. The identified genes were screened for genes with known functions in cell cycle and apoptosis by automated and manual review and included 13 apoptosis-related genes. Among them, the CDK inhibitor p21/WAF/CIP1 was upregulated 19-fold upon induction of AML1/ETO, whereas the apoptosis regulator MCL-1 was induced 2.5-fold. Based on our criteria, no differential expression of other transcriptionally-controlled apoptosis regulators (such as BCL2, BAX, BAK1, BAD or c-flip) was noted. Northern and Western Blot analysis confirmed the strong induction of p21/WAF/CIP1 that paralleled the expression of AML1/ETO 10 hours after PonA treatment. Induction of p21/WAF/CIP1 was independent of the tumor suppressor protein p53 (Dou et al., Proc. Natl. Acad. Sci. 1995), and by Western blot, p53 was undetectable in U937. Northern Blot analysis revealed a higher expression of p21/WAF/CIP1 in the AML1/ETO-positive cell lines Kasumi-1 and SKNO-1 than in the AML1/ETO-negative cell lines HL-60, KG-1 and U937, supporting our finding that AML1/ETO may induce p21/WAF/CIP1. Conclusions: AML1/ETO expression resulted in increased expression of p21/WAF/CIP1, which might contribute to the observed growth arrest and induction of apoptosis caused by the conditional expression of AML1/ETO.

The Oral PKC-β Inhibitor Enzastaurin (LY317615) Suppress Phosphorylation and Induces Apoptosis in Multiple Myeloma Cell Lines by Inhibition of AKT Pathway.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1371-1371
Author(s):  
Antonino Neri ◽  
Sandra Marmiroli ◽  
Pierfrancesco Tassone ◽  
Luigia Lombardi ◽  
Lucia Nobili ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Western Blot ◽  
Cell Lines ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Time Dependent ◽  
Parp Cleavage ◽  
Akt Phosphorylation ◽  
Downstream Target ◽  
Pkc Β

Abstract The PKC pathway has been shown to play a role in the regulation of cell proliferation in several hematologic malignancies. In this study we tested the oral PKC-β inhibitor, Enzastaurin (LY317615 - Eli Lilly) for its therapeutic efficacy in Multiple Myeloma (MM). We first analyzed PKC-β I and II expression by Western blot in a panel of 19 human MM cell lines, showing that 9 cell lines express either 1 or both isoforms. We next examined the growth inhibition effect of Enzastaurin in the same panel of MM cell lines using either WST-1 or MTT assay and cell viability assessment by Tripan Blue exclusion. Eighteen cell lines have IC50 value ranging from 1,2 μM to 12,5 μM. To examine molecular mechanisms whereby Enzastaurin induces cytotoxicity, we performed cell cycle profiling using PI and observed a significant increase of the percentage of cells in the sub G0–G1 fraction. To determine whether Enzastaurin-induced cell death is mediated by apoptosis, we studied by ELISA and Western blot caspase 3 and PARP cleavage. We observed induction of caspase 3 and PARP cleavage in a dose and time dependent fashion. Notably, the broad caspase (Z-VAD-FMK) inhibitor reduced Enzastaurin-induced cytotoxicity. We next determined whether Enzastaurin could inhibit AKT phosphorylation in MM cell lines with constitutive phosphorylation of AKT. Enzastaurin decreased AKT phosphorylation in a dose and time dependent fashion. Phosphorylation of GSK3β, a downstream target protein of AKT, was also markedly inhibited. Phosphorylation of PDK-1, a known upstream activator of AKT, was not affected by Enzastaurin. In conclusion, our results indicate that Enzastaurin-induced cytotoxicity is mediated via activation of caspase. This effect is associated with significant inhibition of AKT activity and its downstream target GSK3 β. Enzastaurin does not alter the phosphorylation of the upstream AKT activator PDK-1. These data suggest that Enzastaurin inhibit AKT signalling pathway and support its evaluation in a murine model of human MM.

Effects of a Novel, Selective Jak2 Inhibitor, AZ60, on STAT5 Signaling and Cellular Growth in Jak2 V617F Cell Lines.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3549-3549
Author(s):  
Joseph M. Gozgit ◽  
Geraldine A. Bebernitz ◽  
Pankaj Patil ◽  
Minwei Ye ◽  
Jiaquan Wu ◽  
...  
Keyword(s):  
Cell Lines ◽  
Family Members ◽  
Jak2 V617f ◽  
Parp Cleavage ◽  
Jak2 Inhibitor ◽  
Kinase Family ◽  
Jak Kinase ◽  
Ic50 Values ◽  
Induction Of Apoptosis ◽  
Dose Dependent

Abstract A role for Jak2 in the etiology of the myeloproliferative diseases (MPDs) was discovered with the identification of a single activating point mutation, V617F, in the pseudokinase domain of JAK2. We have developed a Jak2 inhibitor, AZ60, which inhibits in vitro JAK2 enzyme activity with a Ki of 0.45 nM. AZ60 demonstrates inhibition of STAT5 phosphorylation and proliferation in a Tel-Jak2 engineered cell line with IC50 values of 18 and 23 nM, respectively. To understand the selectivity versus other Jak kinase family members we engineered three additional cell lines containing Tel fusions with the kinase domains of Jak1, Jak3 and Tyk2. Under these settings, AZ60 demonstrates a 15 to 30-fold selectivity for Tel-Jak2 driven STAT5 phosphorylation when compared to other Jak kinase family members. AZ60 was also tested for its ability to inhibit STAT5 phosphorylation and cellular proliferation in two human hematological cell lines, Set-2 and Hel. Set-2 expresses both wt and V617F Jak2, while Hel is homozygous for the Jak2 V617F mutation. AZ60 decreased phospho-STAT5 levels in a dose-dependent manner in both Set-2 and Hel cells with IC50 values of 15 and 25 nM, respectively. Complete inhibition of proliferation and a marked induction of apoptosis were observed in both cell lines following treatment with AZ60. Induction of apoptosis by AZ60 was characterized by a time- and dose-dependent increase in caspase 3/7 activities and PARP-cleavage. These data demonstrate AZ60 is a potent and selective inhibitor of Jak2 and may help decipher the mechanisms underlying Jak2-driven myeloproliferative disease.

Combination of a Spicamycin Analogue KRN5500 and Chemotherapeutic Agents Synergistically Enhances Their Cytotoxicity in Human Myeloma Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4783-4783
Author(s):  
Hirokazu Miki ◽  
Shuji Ozaki ◽  
Osamu Tanaka ◽  
Shiro Fujii ◽  
Shingen Nakamura ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Cell Growth ◽  
Cell Lines ◽  
Therapeutic Potential ◽  
Flow Cytometric Analysis ◽  
Human Tumor ◽  
Chemotherapeutic Agents ◽  
Dependent Manner ◽  
Induced Apoptosis ◽  
Rpmi 8226

Abstract Multiple myeloma (MM) is a plasma cell malignancy characterized by the accumulation of neoplastic plasma cells in the bone marrow. Although new classes of agents such as thalidomide, lenalidomide, and bortezomib have shown marked anti-MM activity in clinical settings, MM remains an incurable disease due to increased resistance to these agents. Therefore, alternative approaches are necessary to overcome drug resistance in MM. KRN5500 is a new derivative of spicamycin produced by Streptomyces alanosinicus (Kirin Pharma, Tokyo, Japan). This drug potently decreases protein synthesis and inhibits cell growth in human tumor cell lines both in vitro and in vivo. Several phase I studies of KRN5500 were conducted in patients with solid tumors, which showed Cmax values of 1000–3000 nM at the maximum tolerated doses. However, no objective anti-tumor response to KRN5500 alone was observed in these patients. In this study, we examined the anti-tumor activity of KRN5500 against MM cells and evaluated its therapeutic potential in combination with other anti-MM agents. MM cell lines and freshly-isolated MM cells were incubated with various concentrations of KRN5500 for 24 hours. Cell proliferation assay showed marked inhibition of cell growth in MM cells such as RPMI 8226, KMS12-BM, and UTMC-2 (IC50 = 10–40 nM), and U266, MM.1S, and primary MM cells (IC50 = 500–1000 nM). Importantly, a chemotherapy-resistant subclone of RPMI 8226 had a similar sensitivity to KRN5500. Annexin V/propidium iodide staining confirmed that KRN5500 induced apoptosis of MM cells in a dose- and time-dependent manner. Moreover, cleavage of poly (ADP-ribose) polymerase (PARP) was detected after 24 hours with only modest activation of caspase-8, -9, and -3 by immunoblotting. Flow cytometric analysis of anti-apoptotic proteins revealed that apoptosis induced by KRN5500 was associated with down-regulation of Mcl-1 and Bcl-2 expression. To determine the effect of KRN5500 on the unfolded protein response (UPR), splicing of XBP-1 mRNA was analyzed by reverse transcription-polymerase chain reaction. In response to stimulation with KRN5500, splicing of XBP-1 mRNA occurred after 24 hours in RPMI 8226 cells, suggesting that KRN5500-induced apoptosis is mediated in part by the inhibition of UPR. Furthermore, synergistic effects on MM cells were observed when KRN5500 was combined with anti-MM agents including melphalan, dexamethasone, and bortezomib. These results suggest that KRN5500 induces apoptosis in MM cells mainly by the caspase-independent pathway and that its unique mechanism of action provides a valuable therapeutic option to overcome drug resistance in patients with MM.

A Small Molecule Stat Inhibitor Blocks Stat3 and Stat5 Phosphorylation and Demonstrates Cytotoxicity In Acute Lymphoblastic Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2904-2904
Author(s):  
Robyn M. Dennis ◽  
Brandon Ballard ◽  
David John Tweardy ◽  
Karen Rabin
Keyword(s):  
Flow Cytometry ◽  
Western Blot ◽  
Cell Line ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Flow Cytometric Analysis ◽  
Positive Control ◽  
Wild Type ◽  
Atp Assay ◽  
Antibody Staining

Abstract Abstract 2904 Survival has improved dramatically in acute lymphoblastic leukemia (ALL), but further gains are unlikely using conventional chemotherapy alone. Several recently discovered, novel cytogenetic lesions with adverse prognostic impact, JAK2 activating mutations and CRLF2 rearrangements, occur in up to 15% of adult and pediatric ALL. These lesions are associated with activation of Jak2 and Stat5, and hold promise as targets for novel therapies affecting these signaling pathways. We performed in vitro testing of a novel small molecule Stat inhibitor, C188-9, in B-lineage ALL cell lines and patient samples with and without JAK2/CRLF2 alterations. C188-9 treatment for one hour at 10 μM inhibited Stat3 and Stat5 phosphorylation in ALL cell lines with JAK2 and CRLF2 alterations, but not in cell lines with wild-type JAK2 and CRLF2, as measured by phospho-flow cytometry (Fig. 1A). Only the cell lines with JAK2 and CRLF2 alterations demonstrated basal Stat5 phosphorylation on Western blot analysis, and this was inhibited by C188-9 treatment (Fig. 1B). C188-9 demonstrated cytotoxicity in ALL cell lines regardless of JAK2/CRLF2 status, with IC50s in the low micromolar concentration range (Fig. 1C). While C188-9 is undergoing investigation currently as a potent inhibitor of Stat3 in acute myeloid leukemia (AML), it also merits further investigation as an agent with Stat5 inhibitory activity and cytotoxicity in ALL. Figure 1. Effects of C188-9 in ALL cell lines. A. Stat3 and Stat5 phosphorylation were determined by flow cytometry in the ALL cell lines MHH-CALL-4 (JAK2/CRLF2 mutated) and Reh (JAK2/CRLF2 wild-type). In each condition, cells were incubated in serum-free media for one hour, followed by incubation with C188-9 or vehicle for one hour, stimulation with vehicle or pervanadate 125 mM for 15 minutes, fixation, permeabilization, phospho-antibody staining for phospho-Stat3 and phospho-Stat5, and flow cytometric analysis. B. Western blot for phospho-Stat5 in K562 cell line (positive control); MHHCALL-4 treated for one hour with C188-9 at 0, 5, or 10 uM; and RS4;11 (JAK2/CRLF2 wild-type ALL cell line). C. IC50 determination by ATP assay for C188-9 in the ALL cell lines MHH-CALL-4 and RS4;11. Each experiment was performed in triplicate. Figure 1. Effects of C188-9 in ALL cell lines. A. Stat3 and Stat5 phosphorylation were determined by flow cytometry in the ALL cell lines MHH-CALL-4 (JAK2/CRLF2 mutated) and Reh (JAK2/CRLF2 wild-type). In each condition, cells were incubated in serum-free media for one hour, followed by incubation with C188-9 or vehicle for one hour, stimulation with vehicle or pervanadate 125 mM for 15 minutes, fixation, permeabilization, phospho-antibody staining for phospho-Stat3 and phospho-Stat5, and flow cytometric analysis. B. Western blot for phospho-Stat5 in K562 cell line (positive control); MHHCALL-4 treated for one hour with C188-9 at 0, 5, or 10 uM; and RS4;11 (JAK2/CRLF2 wild-type ALL cell line). C. IC50 determination by ATP assay for C188-9 in the ALL cell lines MHH-CALL-4 and RS4;11. Each experiment was performed in triplicate. Disclosures: No relevant conflicts of interest to declare.

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