Cancer Drug Resistance Reduction via Co-treatment with Oxaliplatin and Nitazoxanide: Targeting the ABC Transporters.

OBJECTS: Shortly after cancer is diagnosed, a phenomenon develops in cancer cells called multidrug resistance (MDR), in which cell sensitivity against anti-cancer drugs is significantly reduced. The present investigation aimed to assess the effects of nitazoxanide (NTZ), a safe drug, on LS174T/OXP-resistant cells. METHODS: In the current in vitro research, the effects of NTZ and oxaliplatin (OXP) on the viability of LS174T and LS174T/OXP cell lines were evaluated through MTT assay. Then, the changes in expression levels of MDR1, MRP1, BCRP, and LRP genes and proteins were measured by RT-qPCR and western blotting methods, respectively. Lastly, the apoptosis status was assessed by annexin V-FITC/PI staining flow cytometry assay. RESULTS: The IC50 values for cells resistant or sensitive to OXP were revealed (11567 nM vs. 1745 nM; p <0.05 for 24 h incubation, and 5161 nM vs. 882.2 nM; p <0.05 for 48 h incubation). Moreover, NTZ plus OXP led to a leftward shift in the cytotoxicity curve (2004 nM; p = 0.007). This co-treatment significantly decreased the expression of all genes and proteins (p <0.05). Finally, the combination of NTZ and OXP induced a significant increase in apoptosis (p <0.001). CONCLUSION: The data showed that NTZ treatment could increase the sensitivity of LS174T/OXP cell line to the OXP cytotoxic effects. Thus, NTZ may be efficient in reducing drug resistance in clinics by means of the negative regulation of ATP-binding cassette (ABC) transporters. However, further studies are necessary to explain the exact mechanisms of NTZ.

Blockage of Wnt/ß-catenin Signaling Pathway in Colorectal Cancer Resistant Cells by Nitazoxanide Effects on Peptidylarginine Deiminases Expression.

BACKGROUND: Multidrug resistance (MDR) is a major cause of unsuccessful cancer treatment in which drugs are not effective. Therefore, it is necessary to identify the critical mechanisms of the development of MDR and target those with novel compounds. Accordingly, the current study is the first to investigate the combination effect and molecular mechanism of nitazoxanide (NTZ) and oxaliplatin (OXP) on LS174T/OXP-resistant cells. METHODS: The effect of NTZ on OXP cytotoxicity in LS174T and LS174T/OXP cell lines was evaluated by MTT assay. Changes in expression levels of MDR1, MRP1, CTNNB1, peptidylarginine deiminase (PAD)2, and PAD4 genes and proteins were evaluated by RT-qPCR and western blotting methods, respectively. Lastly, the apoptosis assay was performed by flow cytometer. RESULTS: OXP resistant and sensitive cells were identified based on the IC50 values (11567 nM vs. 1745 nM, p<0.05 for 24 h treatment; and 5161 nM vs. 882 nM, p<0.05 for 48 h incubation). The combination of NTZ and OXP for 48 h led to a reduction in IC50 values in resistant cells (2154 nM, p<0.05). The effect of NTZ plus OXP significantly decreased the expression of MDR1 (p<0.001), MRP1 (p<0.05), and CTNNB1 (p<0.001), while PAD2 and PAD4 expression was significantly increased (p<0.001). This combination therapy enhanced the percentage of the sub-G1 population (apoptosed) compared to other groups. CONCLUSION: The results showed that NTZ leads to notable upregulation of PAD2 and PAD4, which can disrupt the Wnt/ß-catenin signaling pathway and reverse the MDR by reducing MDR1 and MRP1 expression.

Expression levels of miR-143-3p and -424-5p in colorectal cancer and their clinical significance.

BACKGROUND: Colorectal cancer (CRC) is one of the most prevalent cancers and microRNAs are involved in colorectal carcinogenesis and progression. The role of our candidate microRNAs (miR-143-3p, -424-5p, -212-3p and -34a-3p) have been investigated in various cancers. OBJECTIVE: The aim of the current study was to evaluate expression levels of microRNAs (miR-143-3p, -424-5p, -212-3p and -34a-3p) in the sera of patients with CRC in order to identify potential non-invasive biomarker for CRC and investigate the relationship between their expression and clinicopathological features of CRC. METHODS: The serological expression of candidate microRNAs were measured in 124 participants, including 62 CRC patients and 62 healthy controls and the serum expression levels of candidate miRNAs were quantified by stemloop reverse transcriptionquantitative polymerase chain reaction. RESULTS: In the present study, results showed a significant upregulation expression level of miR-424-5p (P< 0.001) and decreased expression level of miR143-3p was observed in the sera of patients with CRC (P< 0.001). Receiver operating characteristic (ROC) curve analysis demonstrated the area of miR-424-5p and miR-143-3p under the ROC curve for CRC diagnosis were 0.703 and 0.724 respectively (P< 0.001). In addition, down expression of miR-143-3p was significantly associated with tumor size (P= 0.005) and lymph node metastasis (P= 0.020) in CRC patients. CONCLUSIONS: The present investigation suggested that low expression of miR-143-3p and increasing level of miR-424-5p in CRC patients may play an important role in development of CRC and they could function as potential non-invasive biomarkers for CRC.

DNMT3B -149 C>T and -579 G>T Polymorphisms and Risk of Gastric and Colorectal Cancer: a Meta-analysis.

BACKGROUND: Numerous studies have investigated associations of DNA methyltransferase (DNMT) -149 C>T and -579 G>T polymorphisms with gastric cancer (GC) and colorectal cancer (CRC) susceptibility; however, the findings are inconsistent prompting the present meta-analysis. MATERIALS AND METHODS: Related studies were identified from PubMed, Google scholar, and SID until 10 October 2015. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the associations. RESULTS: Eleven studies were included based on the search criteria for CRC and GC related to the DNMT3B 149 C>T (3,353 cases and 4,936 controls) and DNMT3B 579 G>T (1,387 cases and 2,064 controls) polymorphisms. There was no significant association overall between DNMT3B -149 and 579 polymorphisms and the risk of cancer. In the stratified analysis by cancer type, DNMT3B 579G>T polymorphism was associated with the risk of CRC and GC. While the DNMT3B -149C/T polymorphism was related with a significantly increased risk of CRC in two tested models, dominant (GG+GT vs. TT: OR 0.51, 95 % CI 0.38-0.69; P = 0.00, Pheterogeneity=0.69, I2= 0 %) and heterozygote (GT vs. TT: OR 0.50, 95 % CI 0.37-0.69; P=0.00, Pheterogeneity=0.41, I2= 0 %), no evidence of any association with GC risk was observed as in the pooled analyses. CONCLUSIONS: More studies are needed to assess associations of DNMT3B -149C/T and DNMT3B 579G>T polymorphisms with cancer in different ethnicities with large population sizes to generate comprehensive conclusions.