[Abstract] Objective: To analyze the expression level of miR-224 in cancer tissues and plasma of hepatocellular carcinoma (HCC) patients, and its correlation with clinicopathological characteristics, diagnosis and prognosis of HCC patients, and to further analyze its mechanism of action in the occurrence and development of liver cancer through bioinformatics analysis and in vitro experiments. Methods: The expression level of miR-224 in HCC tissues and normal tissues was analyzed using large sample data from Gene Expression Omnibus (GEO). qPCR method was used to verify the expression level of miR-224 in the tumor tissues and corresponding adjacent tissues that surgically resected from 80 HCC patients in Hebei Provincial People ’s Hospital from January 2017 to January 2020; in addition, the miR-224 level was also examined in plasma samples from 30 HCC patients. The Kaplan-Meier plotter database was used to analyze the correlation between the miR-224 expression and the overall survival time of HCC patients. The biological processes and signal pathways involving miR-224 were analyzed using bioinformatics tools. Hepatocellular carcinoma HepG2 cells were transfected with miR-224 inhibitor, and then Clone formation experiment, Transwell chamber experiment, qPCR and WB methods were used to detect the effect of miR-224 knockdown on the proliferation and invasion of HepG2 cells and the expression level of EMT-related molecules. Results: The results of GEO database analysis showed that the expression level of miR-224 in HCC tissues was significantly higher than that in normal tissues. The results of clinical specimen verification showed that the expression level of miR-224 in the tumor tissues and plasma of HCC patients was significantly higher than that in the corresponding adjacent tissues and plasma from healthy controls (all P<0.01). The expression level of miR-224 was significantly correlated with the TNM stage, lymph node metastasis status and tumor size of HCC patients (P<0.05 or P<0.01). ROC analysis indicated that miR-224 showed a prominent diagnostic value in liver cancer, and the increased expression level of miR-224 was significantly related to the poor prognosis of HCC patients (P<0.05). Functional enrichment analysis revealed that miR-224 was mainly involved in the mTOR signaling pathway, AGE-RAGE signaling pathway, Rap1 signaling pathway, Ras signaling pathway, ErbB signaling pathway, HIF-1 signaling pathway and p53 signaling pathway and other signaling pathways related to tumor occurrence and development. Knockdown of miR-224 could significantly inhibit the colony formation and invasion of HepG2 cells and affect the expression of EMT-related markers (P<0.05 or P<0.01). Conclusion: miR-224 is highly expressed in HCC tissues and plasma and is significantly related to the poor prognosis of HCC patients. Knockdown of miR-224 expression can inhibit the colony formation, invasion and EMT process of liver cancer HepG2 cells.

Objective: To explore the difference in the proliferation inhibition of doxorubicin and dual specific oncolytic adenoviruses (Ad-VT, Ad-T, Ad-VP3 and d-Mock) on breast cancer cells and normal mammary cells. Methods: The proliferation inhibition rates of doxorubicin and recombinant adenovirus(Ad-VT, Ad-T, Ad-VP3and Mock) on breast cancer cells were detected through WST-1 experiment, and the effects of two drugs on the inhibitory rates of normal mammary epithelial cells were also detected. Moreover, the apoptosis rates of doxorubicin and oncolytic adenoviruses on breast cancer cells and normal mammary epithelial cells were evaluated by Annexin V flow cytometry, Hoechst and JC-1 staining, and the difference in the apoptosis rates were also compared. Results: All the recombinant adenovirus could effectively suppress the proliferation of breast cancer cells (P<0.05 or P<0.01), the inhibition effects followed the order ofAd-VT>Ad-T>Ad-VP3>Ad-MOCK, and the inhibition effect was positively correlated with time. Doxorubicin could also effectively suppress the proliferation of breast cancer cells (P<0.05 or P<0.01), and the inhibition effect was markedly enhanced with the increases in does and time. However, doxorubicin also showed strong inhibition effect on the normal mammary epithelial cells, and the inhibition rate achieved 80% under 72 h and 5 ug/ml doxorubicin, while that of oncolytic adenovirus Ad-VT on MCF-10A was 20% at 72 h. The apoptosis effects of oncolytic adenoviruses-induced breast cancer cellwere increased with time, and the apoptosis rate efficiency followed the order of Ad-VT>Ad-T>Ad-VP3>Ad-MOCK, but they displayed low ability to induce normal mammary cell apoptosis. The apoptosis effects of doxorubicin-induced breast cancer cell were similar to that of the normal mammary epithelial cell (P <0.05 or P<0.01), which followed the dose of 0.05<0.5<5 μg/ml. Conclusion: Dual specific oncolytic adenoviruses can effectively suppress the proliferation of breast cancer cells, but they have low inhibition on normal mammary cells, which have displayed superior safety and provide a new method for the biotherapy of tumor.