Small-Molecule Inhibitor BMS-777607 Induces Breast Cancer Cell Polyploidy with Increased Resistance to Cytotoxic Chemotherapy Agents

Abstract

The RON receptor tyrosine kinase is a therapeutic target for cancer treatment. Here, we report therapeutic effect and phenotypic change of breast cancer cells in response to BMS-777607, a RON tyrosine kinase inhibitor. Treatment of breast cancer cells with BMS-777607 at therapeutic doses inhibited cancerous clonogenic growth but had only minimal effect on cell apoptosis. Significantly, BMS-777607 induced extensive polyploidy with multiple sets of chromosomes in cancer cells. This effect is independent of RON expression. Knockdown of RON in T-47D and ZR-75-1 cells by specific siRNA did not prevent polyploid formation. Immunofluorescent analysis of a-tubulin and g-tubulin expression in polyploid cells revealed that BMS-777607 disrupts bipolar spindle formation and causes multipolar-like microtubule assembly. Also, both metaphase equatorial alignment and chromosomal segregation were absent in polyploid cells. These results suggest that cellular mitosis arrests at prophase/pro-metaphase and fails to undergo cytokinesis. By analyzing kinase-inhibitory profiles, aurora kinase B was identified as the target molecule inhibited by BMS-777607. In BMS-777607-treated cells, aurora kinase B was inhibited followed by protein degradation. Moreover, BMS-777607 inhibited Ser10 phosphorylation of histone H3, a substrate of aurora kinase B. Chemosensitivity analysis indicated the resistance of polyploid cells toward chemotherapeutics. Treatment with doxorubicin, bleomycin, methotrexate, and paclitaxel significantly increased cellular IC 50 values. These findings highlight the theory that BMS-777607 acts as a multikinase inhibitor at therapeutic doses and is capable of inducing polyploidy by inhibiting aurora kinase B. Increased resistance of polyploid cells to cytotoxic chemotherapeutics could have a negative impact on targeted cancer therapy using BMS-777607. Mol Cancer Ther; 12(5); 725-36. Ó2013 AACR.

Efficacy of Anti-RON Antibody Zt/g4–Drug Maytansinoid Conjugation (Anti-RON ADC) as a Novel Therapeutics for Targeted Colorectal Cancer Therapy

“…Nuclear DNAs were stained with 4 0 ,6-diamidino-2-phenylindole (DAPI). Immunofluorescence was observed under an Olympus BK71 microscope equipped with DUS/fluorescent apparatus as previously described (30). …”

Synergistic Activities of MET/RON Inhibitor BMS-777607 and mTOR Inhibitor AZD8055 to Polyploid Cells Derived from Pancreatic Cancer and Cancer Stem Cells

“…Studies from tumor xenograft models have shown that BMS-777607 at 6.25 mg/kg (C max ¼ 4.5 mmol/L) has a therapeutic effect, which significantly inhibits tumor growth mediated by gastric GTL-16 cancer cells that overexpress MET (16). We have recently observed that BMS-777607 inhibits clonogenic growth and induces apoptosis in breast cancer cells exclusively expressing RON (17). Moreover, BMS-777607 induces extensive polyploidy in breast cancer cells at therapeutic doses by inhibition of aurora kinase B (AUKB; ref.…”

“…Moreover, BMS-777607 induces extensive polyploidy in breast cancer cells at therapeutic doses by inhibition of aurora kinase B (AUKB; ref. 17). In this sense, BMS-777607 can be considered as a multi-TKI (16,17).…”

“…17). In this sense, BMS-777607 can be considered as a multi-TKI (16,17). Currently, BMS-777607 is under clinical phase I trials for patients with advanced cancers (http://clinicaltrials.gov; trial identification number: NCT01721148).…”

Hepatocyte growth factor-like protein is required for prostate tumor growth in the TRAMP mouse model

“…One of these receptors, the Ron receptor tyrosine kinase, has been implicated as an oncogene in numerous reports [3-7], and is emerging as a cancer therapeutic target [6]. While the use of selective inhibitors and monoclonal antibodies against Ron have shown promise in vitro and in vivo inhibiting tumor growth, potential side effects and lack of complete inhibition [6, 8, 9] call for the development of new therapeutic approaches. Hepatocyte growth factor-like protein, HGFL, is the ligand for Ron receptor tyrosine kinase.…”