Lysosome-associated protein transmembrane4β is involved in multidrug resistance processes of colorectal cancer.

Colorectal cancer (CRC) is one of the most common reasons for cancer-associated mortality worldwide. The present study aimed to investigate the drug resistance mechanism of the oxaliplatin (OXA)-resistant HT-29 cell line (HT-29/L-OHP) and examine the expression of lysosome-associated protein transmembrane 4 beta (LAPTM4 beta), a drug resistance-associated gene. In the present study, a drug concentration gradient method was used to establish the drug-resistant HT-29/L-OHP cell line. Cell apoptosis was analyzed by flow cytometry. LAPTM4 beta mRNA expression was examined by reverse transcription-quantitative polymerase chain reaction analysis and LAPTM4 beta-35 expression was examined by western blot analysis. Cell morphology of the HT-29/L-OHP drug-resistant cell line was examined. The results indicated that the intercellular space among HT-29 cells was small, with aggregative growth while the intercellular space among HT-29/L-OHP cells was large, with scattered growth. The apoptotic rate in HT-29/L-OHP cells (11.7%) was significantly lower compared with that in HT-29 cells (17.7%) (P<0.05). LAPTM4 beta mRNA expression in HT-29/L-OHP cells was significantly increased compared with that in HT-29 cells (P<0.05). The relative expression of LAPTM4 beta-35 protein in HT-29/L-OHP cells was significantly higher compared with that inHT-29 cells (P<0.05). In conclusion, LAPTM4 beta may be involved in the multidrug resistance processes of CRC. Therefore, LAPTM4 beta may serve as a novel biomarker for drug resistance of CRC.