ABSTRACT
Arsenic trioxide (ATO) is used as a chemotherapeutic agent for the treatment of acute promyelocytic leukemia. However, increasing drug resistance is reducing its efficacy. Therefore, a better understanding of ATO resistance mechanism is required. In this study, we established an ATO-resistant human epidermoid carcinoma cell line, KB/ATO, from its parental KB-3-1 cells. In addition to ATO, KB/ATO cells also exhibited cross-resistance to other anticancer drugs such as cisplatin, antimony potassium tartrate, and 6-mercaptopurine. The arsenic accumulation in KB/ATO cells was significantly lower than that in KB-3-1 cells. Further analysis indicated that neither application of P-glycoprotein inhibitor, breast cancer resistant protein (BCRP) inhibitor, or multidrug resistance protein 1 (MRP1) inhibitor could eliminate ATO resistance. We found that the expression level of ABCB6 was increased in KB/ATO cells. In conclusion, ABCB6 could be an important factor for ATO resistance in KB/ATO cells. The ABCB6 level may serve as a predictive biomarker for the effectiveness of ATO therapy.
ABSTRACT
The epidermal growth factor receptor (EGFR) provides a rational target for cancer therapy as it is commonly overexpressed in a variety of solid tumors, and its deregulation is correlated with resistance to chemotherapy and radiotherapy and a poor prognosis. Cetuximab (C255), a specific monoclonal antibody directed against EGFR, is synergistic with chemotherapy and radiotherapy and has been licensed for the treatment of irinotecan refractory colorectal cancer (CRC) and squamous cell cancer of the head and neck (SCCHN), which express EGFR. In addition, the clinical trials about cetuximab for the treatment of non-small cell lung cancer (NSCLC), breast and pancreas carcinoma are ongoing, and cetuximab has been proven to a novel strategy for the treatment of cancer with the overexpression of EGFR.
ABSTRACT
Multidrug resistance(MDR)of tumor cells has become the main impediment that influence the curative effect of cancer chemotherapy. Although there are many mechanisms can generate the multidrug resistance, the overexpression of P-glycoprotein encoded by the multidrug resistance-1(mdr1) gene is the main cause in the formation of MDR. Seaching for innocuous and effective reversal of MDR is not only a method of improving the efficiency of cancer chemotherapy but also the problem desiderated to be resolved in chemotherapy domain.