MicroRNA-205-5p regulates the chemotherapeutic resistance of hepatocellular carcinoma cells by targeting PTEN/JNK/ANXA3 pathway.

Hepatocellular carcinoma (HCC) is a common malignant tumor of the digestive system, and patients with advanced HCC have a poor outlook, partly due to resistance to chemotherapeutic drugs. Previous studies have implicated microRNAs in the regulation of chemoresistance, and we have previously shown that microRNA (miR)-205-5p is down-regulated in multiple hepatoma cell lines. Here, we investigate whether miR-205-5p is involved in chemotherapeutic resistance in HCC. Expression of miR-205-5p was measured by real-time quantitative reverse transcription PCR and cell viability was determined using a CCK-8 cell viability assay. Expression of proteins in the PTEN/JNK/ANXA3 pathway were assessed via Western blotting. We found that miR-205-5p expression was down-regulated in all HCC cell lines investigated. In addition, miR-205-5p expression was upregulated by 5-fluorouracil (5-Fu) treatment in Bel-7402 (Bel) cells. Interestingly, miR-205-5p expression was increased in multidrug-resistant Bel-7402/5-Fu (Bel/Fu) cells, compared with Bel cells. We next demonstrated that sensitivity to 5-Fu was increased in Bel/Fu cells after treatment with a miR-205-5p inhibitor. Similarly, increased resistance to 5-Fu was observed in Bel cells after transfection with a miR-205-5p mimic. We injected nude mice with Bel/5-Fu cells to promote tumor growth, and found that co-treatment with a miR-205-5p antagomir and 5-Fu slowed tumor growth more than either treatment alone. Finally, we found that these effects were all associated with changes in the PTEN/JNK/ANXA3 pathway. In conclusion, inhibition of miR-205-5p may reverse chemotherapeutic resistance to 5-Fu, and this may occur via the PTEN/JNK/ANXA3 pathway.

[DADLE suppresses the proliferation of human liver cancer HepG2 cells by activation of PKC pathway and elevates the sensitivity to cis-diammine dichloridoplatium].

OBJECTIVE: To investigate the effect of DADLE, a δ-opioid receptor agonist, on the proliferation of human liver cancer HepG2 cells and explore the mechanism involving PKC pathway. METHODS: HepG2 cells were treated with DADLE at different doses (0.01, 0.1, 1.0 and 10 µmol/L). Cell viability was determined using methyl thiazolyl terazolium (MTT) assay. The expression of PKC mRNA and p-PKC protein were examined by RT-PCR and Western blot assay. After treated separately with DADLE plusing NAL or PMA, the cell cycle of HepG2 cells was analyzed by flow cytometer. MTT was used to detect their proliferation capacity and Western blot was used to examine the p-PKC expression. The growth inhibitory rate of HepG2 cells treated with DADLE and cis-diammine dichloridoplatinum (CDDP) was analyzed. RESULTS: DADLE at different concentrations showed an inhibitory effect on the proliferation of HepG2 cells though inhibiting the expression of PKC mRNA and p-PKC protein. The results of flow cytometry showed that compared with the control group, the percentage of S + G(2)/M cells in DADLE-treated group was lowered by 3.94% (P < 0.01). Meanwhile, after treated with NAL and PMA, the percentage was elevated by 3.22% and 3.63%, respectively (P < 0.01). The MTT and Western blot assays showed that compared with the control group, the values of A570 and p-PKC protein levels in the HepG2 cells of DADLE-treated group were significantly decreased (P < 0.01). After treatment with NAL and PMA, the values of A570 and p-PKC protein levels were elevated significantly (P < 0.01). The growth inhibitory rate of DADLE + CDDP group was 79.9%, significantly lower than 25.2% and 43.2% of the DADLE and CDDP groups, respectively. CONCLUSIONS: Activation of δ-opioid receptor by DADLE inhibits the apoptosis of human liver cancer HepG2 cells. The underlying mechanism may be correlated with PKC pathway. DADLE can enhance the chemosensitivity of HepG2 cells to CDDP.

[Expression and clinical significance of anti-apoptotic factors PED/PEA-15 and XIAP in hepatocellular carcinoma].

OBJECTIVE: To investigate the expression of apoptosis arrestin PED/PEA-15 and XIAP in hepatocellular carcinoma (HCC) and explore their relationship with clinicopathological factors of HCC. METHODS: The mRNA expressions of PED/PEA-15 and XIAP genes were detected by RT-PCR (reverse transcription-polymerase chain reaction) in resected liver tumor tissues and corresponding adjacent noncancerous tissues from 40 HCC patients and normal liver tissues from 12 patients with benign lesions. Their protein levels were detected by Western blot. RESULTS: The mRNA expressions of PED/PEA-15 and XIAP genes and their proteins were significantly higher than those in adjacent tissues and normal tissues (0.636 +/- 0.061, 0.352 +/- 0.068, 0.179 +/- 0.036; 0.579 +/- 0.090, 0.344 +/- 0.084, 0.184 +/- 0.038) (P < 0.01). The mRNA levels of PED/PEA-15 and XIAP genes and their protein levels were significantly associated with the pathological grade and clinical stage of HCC (P < 0.05). However there was not a significant correlation with such clinicopathological features as age, gender, size of tumor, tumor load, metastasis and recurrence (P > 0.05). CONCLUSION: The expressions of apoptosis arrestin PED/PEA-15 and XIAP are elevated in HCC as compared with adjacent tissues and normal tissues. Thus it may serve as both a reference indicator for biological behaviors of HCC and a new target for gene therapy.