[Aldo-keto reductase family 1 B10 participates in the regulation of hepatoma cell cycle through p27/p-Rb signaling pathway].

Objective: Aldo-keto reductase family 1 member B10 (AKR1B10) pathogenesis, early diagnosis and prognosis are closely related with hepatoma. Therefore, this study explores the effect and mechanism of AKR1B10 on cell cycle in hepatoma cells. Methods: HepG2 cells were infected with lentivirus LV-AKR1B10-shRNA or treated with epalrestat, an AKR1B10 inhibitor. The expression level of AKR1B10 was detected by Western blot assay and real-time fluorescence quantitative PCR (RT-qPCR). Decreased AKR1B10 activity was detected by reduced coenzyme II (NADPH) absorbance at 340 nm. The low expression of AKR1B10 and the effect of different concentrations of epalrestat on cell proliferation and cell cycle were detected by CCK-8 method and flow cytometry. The protein expression levels of p-rb, cyclin D1, E1, p27 in HepG2 cells were detected by Western blot. The mean of the two samples was tested using independent sample t-test. Results: AKR1B10 expression level in hepatoma cells was significantly increased compared to normal liver cells, and the relative expression level of AKR1B10 protein in HepG2 cells was 6.71 ± 1.11 (P = 0.012). Epalrestat was significantly inhibited with the enzymatic activity of AKR1B10 in a dose-dependent manner. AKR1B10 gene in HepG2 cells was effectively silenced. HepG2 cells treated with different concentrations of epalrestat (AKR1B10 inhibitor) for 24, 48 and 72 h had inhibited cell proliferation, promoted G0/G1 cell cycle arrest, reduced the expression of p-Rb, cyclin D1, and cyclin E1 and increased the expression of cyclin dependent kinase inhibitor p27 expression. Conclusion: AKR1B10 inhibitory expression and activity can promote G0/G1 cell cycle arrest in HepG2 cells through the p27 / p-Rb pathway.

[AKR1B10 inhibitor enhances the inhibitory effect of sorafenib on liver cancer xenograft].

Objective: To investigate the inhibitory effect of AKR1B10 inhibitor combined with sorafenib on hepatocellular carcinoma (HCC) xenograft growth. Methods: HepG2 xenograft model was established in nude mice. The mice were then randomly divided into four groups: control group, epalrestat monotherapy group, sorafenib monotherapy group and combination treatment group. Tumor volume, tumor weight, T/C ratio and the change in body weight of nude mice in each group were compared to evaluate the curative effect. Immunohistochemistry staining was used to detect the expression of Ki-67 in tumor tissues to evaluate the proliferation status of tumor cells. One-way analysis of variance was used to compare the differences between the groups. Student's t-test was used to test means of two groups and chi-square test was used for multiple samples. Results: The differences of the grafted tumor volume before and after treatment between the control group, epalrestat group, sorafenib group and combined therapy group was 238.940 ± 39.813, 124.991 ± 84.670, -26.111 ± 11.518, and -54.072 ± 17.673(mm(3)), respectively, (F = 37.048, P < 0.001). The tumor mass were 0.273 ± 0.140, 0.158 ± 0.078, 0.079 ± 0.054, 0.045 ± 0.024 (g), (F = 16.594, P < 0.001); T/C ratio were 100%, 57.9%, 28.9%, 16.5%, and Ki-67 positive rate were 23.295 ± 6.218, 13.503 ± 3.392, 7.325 ± 2.257, 4.664 ± 1.189 (%), (χ(2) = 822.203, P < 0.001) . The tumor volume (t = -3.579, P = 0.002) and Ki-67 positive rate (t = -10.003, P < 0.001) in epalrestat monotherapy group were significantly lower than control group. The tumor volume (t = 2.056, P = 0.025), tumor mass (t = 2.101, P = 0.043), and Ki-67 positive rate (t = -2.850, P = 0.005) in combination treatment group were significantly lower than sorafenib monotherapy group. Compared with the control group, the body weight of nude mice in the treatment group decreased to a certain extent, but there was no statistically significant difference between epalrestat monotherapy group and control group (t = -1.599, P = 0.262), and combined therapy and sorafenib monotherapy group (t = -0.051, P = 0.96). Conclusion: AKR1B10 inhibitor enhanced the inhibitory effect of sorafenib on hepatocellular carcinoma xenograft.

Knockdown of ferroportin accelerates erastin-induced ferroptosis in neuroblastoma cells.

OBJECTIVE: Ferroptosis is a new-found iron-dependent form of non-apoptotic regulated cell death (RCD), which is activated on therapy with several antitumor agents, but the potential mechanism remains unclear. Erastin, exhibiting selectivity for RAS-mutated cancer cells, induces ferroptosis by increasing iron and lipid reactive oxygen species (ROS) levels in cell. Ferroportin (Fpn), the sole iron export protein, participates in the regulation of intracellular iron concentration. In this study, we investigated the role of Fpn on ferroptosis induced by erastin in SH-SY5Y cells. MATERIALS AND METHODS: The cell viability was determined by CellTiter 96® AQueous Non-Radioactive Cell Proliferation Assay kit. The activity of caspase-3 was measured by ELISA kit. qRT-PCR was performed to examine the mRNA expression of Fpn. Western blot assay was conducted to examine the expression level of marker proteins. Specific commercial kits were used to examine the levels of MDA, ROS and iron in cells, respectively. RESULTS: Ferroptosis was evaluated by intracellular lipid ROS level and iron concentration. Hepcidin could prevent erastin-induced ferroptosis by degrading Fpn. Erastin (5 µg/mL) was observed to induce ferroptosis in neuroblastoma cells at 6 hours, which was promoted by knockdown of Fpn. The expression of Fpn gene and protein was decreased in SH-SY5Y cells treated with erastin. After treatment with erastin, Fpn siRNA transfection in SH-SY5Y cells was able to accelerate ferroptosis-associated phenotypic changes. Fpn acted as a negative regulator of ferroptosis by reducing intracellular iron concentration. Knockdown of Fpn enhanced anticancer activity of erastin. CONCLUSIONS: These results suggested that knockdown of Fpn accelerated erastin-induced ferroptosis by increasing iron-dependent lipid ROS accumulation, highlighting Fpn as a potential therapeutic target site for neuroblastoma. Thus, Fpn inhibitors may provide new access for chemosensitization of neuroblastoma.

Telomerase inhibition strategies by siRNAs against either hTR or hTERT in oral squamous cell carcinoma.

Human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) are considered effective molecular targets for current anticancer therapy. In this study, we investigated the therapeutic effects of targeting hTR and hTERT individually or in combination by recombinant adenovirus-delivered small interfering RNA (siRNA) in oral squamous cell carcinoma (OSCC) Tca8113. Further, we screened the optimal strategy for RNA interference. Our results show that these different recombinant adenoviruses specifically reduced the levels of hTR mRNA, hTERT mRNA, hTERT protein and telomerase activity in Tca8113 cells. Moreover, they successfully inhibited xenograft tumor growth in nude mice. The potency of their antitumor activities was ranked as follows: anti-hTR >anti-hTR+anti-hTERT >anti-hTERT. Therefore, we demonstrated that the siRNA-expressing recombinant adenoviruses were an effective anticancer tool for treatment of OSCC. Furthermore, the anticancer effect of solely targeting hTR was more direct and efficient, compared with the effect of targeting hTR and hTERT in combination, or hTERT exclusively. The mechanism of this anticancer effect in OSCC was not only related to the inhibition of cell proliferation and the induction of cell apoptosis, but might also involve the inhibition of tumor angiogenesis.