ABSTRACT
Three molecular targeted tyrosine kinase inhibitors (TKI) were conjugated to classical platinum-based drugs with an aim to circumvent TKI resistance, predominately mediated by the emergence of secondary mutations on oncogenic kinases. The hybrids were found to maintain specificity towards the same oncogenic kinases as the original TKI. Importantly, they are remarkably less affected by TKI resistance, presumably due to their unique structure and the observed dual mechanism of anticancer activity (kinase inhibition and DNA damage). The study is also the first to report the application of a hybrid drug approach to switch TKIs from being efflux transporter substrates into non-substrates. TKIs cannot penetrate into the brain for treating metastases because of efflux transporters at the blood brain barrier. The hybrids were found to escape drug efflux and they accumulate more than the original TKI in the brain in BALB/c mice. Further development of the hybrid compounds is warranted.
Subject(s)
Antineoplastic Agents/administration & dosage , Antineoplastic Agents/chemical synthesis , Carcinoma, Non-Small-Cell Lung/drug therapy , Drug Resistance, Neoplasm/drug effects , Lung Neoplasms/drug therapy , Animals , Antineoplastic Agents/pharmacology , Brain Chemistry , Carcinoma, Non-Small-Cell Lung/genetics , Cell Line, Tumor , Cisplatin/administration & dosage , Cisplatin/chemical synthesis , Cisplatin/pharmacology , Erlotinib Hydrochloride/administration & dosage , Erlotinib Hydrochloride/chemical synthesis , Erlotinib Hydrochloride/pharmacology , Humans , K562 Cells , Lung Neoplasms/genetics , Mice , Molecular Targeted Therapy , Mutation , Piperidines/administration & dosage , Piperidines/chemical synthesis , Piperidines/pharmacology , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Quinazolines/administration & dosage , Quinazolines/chemical synthesis , Quinazolines/pharmacology , Xenograft Model Antitumor AssaysABSTRACT
We have recently reported that vatalanib, an orally active small molecule multi-tyrosine kinase inhibitor (Hess-Stumpp et al., 2005 [1]), can sensitize multidrug resistant (MDR) colon cancer cells to chemotherapy under hypoxia by inhibiting two MDR transporters ABCB1 and ABCG2 (To et al., 2015 [2]). This data article describes the possible circumvention of resistance to specifically platinum (Pt)-based anticancer drugs by vatalanib via inhibition of two other efflux transporters ABCC2 and ATP7A. Data from the flow cytometric transporter efflux assay showed specific inhibition of ABCC2 activity by vatalanib in stable transfected cells and ABCC2-overexpressing oxaliplatin-resistant colon cancer cells HCT116/Oxa. We also performed the transporter ABCC2 ATPase assay and showed an increase in ATP hydrolysis by ABCC2 in the presence of vatalanib. ATP7A mRNA expression was also shown to be upregulated in HCT116/Oxa cells. Vatalanib was shown to suppress this upregulated ATP7A expression. Data from the cellular Pt accumulation assay showed a lower Pt accumulation in HCT116/Oxa cells than the parental sensitive HCT116 cells. Vatalanib was shown to increase cellular Pt accumulation in a concentration-dependent manner. Combination of oxaliplatin and vatalanib was shown to restore the suppressed apoptosis in HCT116/Oxa cells.
ABSTRACT
Cancer microenvironment is characterized by significantly lower oxygen concentration. This hypoxic condition is known to reduce drug responsiveness to cancer chemotherapy via multiple mechanisms, among which the upregulation of the ATP-binding cassette (ABC) efflux transporters confers resistance to a wide variety of structurally unrelated anticancer drugs. Vatalanib (PTK787/ZK22584) is a multitargeted tyrosine kinase inhibitor for all isoforms of VEGFR, PDGFR and c-Kit, which exhibit potent anticancer activity in vitro and in vivo. We investigated the potentiation effect of vatalanib on the anticancer activity of conventional cytotoxic drugs in colon cancer cell lines under both normoxic and hypoxic conditions. Mechanistically, vatalanib was found to inhibit ABCG2 and ABCB1 efflux activity, presumably by acting as a competitive inhibitor and interfering with their ATPase activity. Under hypoxic growth condition, ABCG2 and ABCB1-overexpressing cells sorted out by FACS technique as side population (SP) were found to be significantly more responsive to SN-38 (ABCG2 and ABCB1 substrate anticancer drug) in the presence of vatalanib. The anchorage independent soft agar colony formation capacity of the SP cells was remarkably reduced upon treatment with a combination of SN-38 and vatalanib, compared to SN-38 alone. However, vatalanib, at concentrations that produced the circumvention of the transporters-mediated resistance, did not appreciably alter ABCG2/ABCB1 mRNA or protein expression levels or the phosphorylation of Akt and extracellular signal-regulated kinase (ERK1/2). Our study thus advocates the further investigation of vatalanib for use in combination chemotherapy to eradicate drug-resistant cancer cells under hypoxia.
Subject(s)
ATP-Binding Cassette Transporters/antagonists & inhibitors , Angiogenesis Inhibitors/pharmacology , Colonic Neoplasms/drug therapy , Drug Resistance, Multiple/drug effects , Drug Resistance, Neoplasm/drug effects , Neoplasm Proteins/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , ATP Binding Cassette Transporter, Subfamily B/antagonists & inhibitors , ATP Binding Cassette Transporter, Subfamily B/genetics , ATP Binding Cassette Transporter, Subfamily B/metabolism , ATP Binding Cassette Transporter, Subfamily G, Member 2 , ATP-Binding Cassette Transporters/genetics , ATP-Binding Cassette Transporters/metabolism , Antineoplastic Agents, Phytogenic/agonists , Antineoplastic Agents, Phytogenic/pharmacology , Apoptosis/drug effects , Camptothecin/agonists , Camptothecin/analogs & derivatives , Camptothecin/pharmacology , Cell Hypoxia , Cell Line, Tumor , Colonic Neoplasms/metabolism , HEK293 Cells , Humans , Irinotecan , Isoenzymes/antagonists & inhibitors , Isoenzymes/metabolism , Neoplasm Proteins/genetics , Neoplasm Proteins/metabolism , Phthalazines/pharmacology , Proto-Oncogene Proteins c-kit/antagonists & inhibitors , Proto-Oncogene Proteins c-kit/metabolism , Pyridines/pharmacology , Receptors, Platelet-Derived Growth Factor/antagonists & inhibitors , Receptors, Platelet-Derived Growth Factor/metabolism , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Receptors, Vascular Endothelial Growth Factor/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/metabolismABSTRACT
BACKGROUND AND PURPOSE: Pelitinib is a potent irreversible EGFR TK inhibitor currently in clinical trials for the treatment of lung cancer. Hyperthermia has been applied concomitantly with chemotherapy and radiotherapy to enhance treatment outcome. In this study, we investigated the ability of the combination of pelitinib with other conventional anticancer drugs to specifically target cancer cells with up-regulated efflux transporters ABCB1/ABCG2 after hyperthermia as a novel way to eradicate the cancer stem-like cells responsible for cancer recurrence. EXPERIMENTAL APPROACH: Alterations in intracellular topotecan accumulation, the efflux of fluorescent probe substrates, expression and ATPase activity of ABCB1/ABCG2 and tumoursphere formation capacity of side population (SP) cells sorted after hyperthermia were examined to elucidate the mechanism of pelitinib-induced chemosensitization. KEY RESULTS: While pelitinib did not modulate ABCB1/ABCG2 expressions, the combination of pelitinib with transporter substrate anticancer drugs induced more marked apoptosis, specifically in cells exposed to hyperthermia. The flow cytometric assay showed that both ABCB1- and ABCG2-mediated drug effluxes were significantly inhibited by pelitinib in a concentration-dependent manner. The inhibition kinetics suggested that pelitinib is a competitive inhibitor of ABCB1/ABCG2, which is consistent with its ability to stimulate their ATPase activity. SP cells sorted after hyperthermia were found to be more resistant to anticancer drugs, presumably due to the up-regulation of ABCB1 and ABCG2. Importantly, pelitinib specifically enhanced the chemosensitivity but reduced the tumoursphere formation capacity of these SP cells. CONCLUSIONS AND IMPLICATIONS: This study demonstrated a novel approach, exploiting drug resistance, to selectively kill cancer stem-like cells after hyperthermia.