The potential therapeutic effect of melatonin in oxaliplatin combination therapy against chemoresistant colorectal cancer cells.

BACKGROUND: Oxaliplatin is one of the main therapeutics in colorectal cancer (CRC) chemotherapy. However, in light of multidrug resistance (MDR) phenotype development, the efficacy of oxaliplatin has decreased. This study aimed to assess the potential therapeutic effect of melatonin in oxaliplatin combination therapy for drug-resistant colorectal cancer cells. METHODS AND RESULTS: Initially, the oxaliplatin-resistant cell line was created of LS174T (LS174T/DR) by using the oxaliplatin IC50 concentration and resting cycles. MTT assays and flow cytometry were applied for assessing cell viability and apoptotic cells. The mRNA expression level of Bax, Bcl2, MT1, MT2, and ABCB1 as well as protein levels of ABCB1, Bcl2, BAX were measured by the qRT-PCR and western blot techniques respectively. P-gp activity was assessed by Rho123 staining. The IC50 concentration of oxaliplatin in resistant cells was increased from 500.7 ± 0.2 nM to 7119 ± 0.1 nM. Bcl2, MT1, MT2, and ABCB1 mRNA plus protein expression levels of Bcl2 and ABCB1 were significantly reduced in resistant cells, along with a marked increase in Bax mRNA and protein levels compared to parental cells. Rho 123 staining revealed a marked reduction in P-gp activities in the combination-treated group compared to the oxaliplatin-treated group. CONCLUSIONS: The results of cytotoxicity assays, MTT, and flow cytometry revealed that the combination of melatonin and oxaliplatin exerts synergistic effects on induction of oxaliplatin's cytotoxicity in CRC. Our research suggests that combining the treatments of melatonin and oxaliplatin may be considered as a new approach to overcoming oxaliplatin resistance in CRC patients.

The effect of encomir-93 mimic transfection on the expression of miR-93 and PSA and androgen receptor in prostate cancer LNcap cell line.

OBJECTIVES: Prostate cancer (PCa) is one of the most common cancers in men with high mortality rate which is a major concern for men's health. However, the molecular mechanisms remain poorly understood. miR-93 is an important oncogene which may have important function in prostate cancer.So, this study aimed to predict that encomir-93 mimic transfection on the expression of miR-93 and PSA and AR in prostate cancer LNcap cell line. METHODS: Lymph node carcinoma of the prostate (LNCaP) was cultured and then miR-93 mimics was designed, synthesized and the transfected to LNCaP. The expression level of prostate-specific antigen (PSA) and androgen receptor (AR) was determined via Real-time PCR after treated with 15 pmol of miR-93 mimics. RESULTS: miR-93 mimic transfection led to significant increase in PSA and AR expression in comparison with control group (p≤0.05). CONCLUSIONS: The miR-93 and its target genes has important role in PCa progression via enhancement in PSA and AR expression. Further research on the function of the miR-93 and its target genes in tumorgenesis and progression PCa could be helpful for the treatment of prostate cancer.