Cholesterol-conjugated let-7a mimics: antitumor efficacy on hepatocellular carcinoma in vitro and in a preclinical orthotopic xenograft model of systemic therapy.

BACKGROUND: A major challenge to the clinical utility of let-7 for hepatocellular carcinoma (HCC) therapy is the lack of an effective carrier to target tumours. We confirmed the high transfection efficiency of cholesterol-conjugated let-7a miRNA mimics (Chol-let-7a) in human HCC cells, as well as their high affinity for liver tissue in nude mice. However, their antitumor efficacy via systemic delivery remains unknown. METHODS: We explored the effects of Chol-let-7a on HCC in vitro and in vivo. Cell viability and mobility, let-7a abundance and the target ras genes was measured. Live-cell image and cell ultrastructure was observed. Antitumor efficacy in vivo was analyzed by ultrasonography, hispatholgogy and transmission electronic microscopy in a preclinical model of HCC orthotopic xenografts with systemic therapy. RESULTS: Chol-let-7a inhibited the viability and mobility of HCC cells. Chol-let-7a was primarily observed in the cytoplasm and induced organelle changes, including autophagy. Mild changes were observed in the cells treated with negative control miRNA. Chol-let-7a reached HCC orthotopic tumours, significantly inhibited tumour growth, and prevented local invasion and metastasis. Compared to control tumours, Chol-let-7a-treated tumours showed more necrosis. Tumour cells showed no significant atypia, and mitoses were very rare after systemic Chol-let-7a therapy. Furthermore, let-7a abundance in orthotopic xenografts was coincident with a reduction in the expression of 3 human ras mRNAs and RAS proteins. CONCLUSIONS: Chol-let-7a exerted significant antitumor effects by down-regulating all human ras genes at the transcriptional and translational levels. Chol-let-7a inhibited cell proliferation, growth, and metastasis, and mainly functioned in the cytoplasm. Chol-let-7a represents a potential useful modified molecule for systemic HCC therapy.

[Effect of TTRAP expression on apoptosis induced by hydroquinone in HL-60 cells in vitro.].

OBJECTIVE: To study the effect of TTRAP expression on apoptosis induced by hydroquinone in HL-60 cells in vitro, and explore the relationship between TTRAP expression and the apoptosis. METHODS: Apoptotic and necrotic rate was examined by flow cytometer with Anti-AnnexinV/FITC Plus PI staining. The mRNA expression of TTRAP was detected by RT-PCR. The differences in different treated groups were compared. RESULTS: After different concentrations of hydroquinone to the cells for 0, 4, 8, 12 h culture, were added, the cell apoptotic rate in different concentrations of hydroquinone groups was significantly higher than that in blank control groups. The optimal concentration of hydroquinone was 200 micromol/L, lasting for 8 h. When it was 250 micromol/L, the necrotic rate increased significantly. The apoptosis induced by hydroquinone was associated with the culture time at the concentration of 200 micromol/L, and the peak apoptotic time was 8 h. Then the apoptotic rate decreased and necrotic rate increased. Furthermore, with the concentrations of hydroquinone increased and time lasted for 8 h, the apoptotic rate of cells increased, the amount of TTRAP expression in the mRNA level also increased accordingly. When the concentrations of hydroquinone was above 250 micromol/L, necrotic rate increased sharply, and the amount of TTRAP expression decreased. CONCLUSION: Hydroquinone could induce apoptosis of HL-60 cells. The up-regulation of TTRAP expression may promote hydroquinone to induce HL-60 cells to go into apoptosis in vitro with dose-effect and time-effect relationship.

Targeting chemotherapy-induced PTX3 in tumor stroma to prevent the progression of drug-resistant cancers.

The tumor microenvironment has been suggested to participate in tumorigenesis, but the nature of the communication between cancer cells and the microenvironment, especially in response to anticancer drugs, remains obscure. We determined that activation of the CCAAT/enhancer binding protein delta (CEBPD) response to Cisplatin and 5-Fluorouracil in cancer-associated macrophages and fibroblasts contributed to the metastasis, invasion, acquired chemoresistance and stemness of cancer cells by in vitro and in vivo assays. Specifically, reporter and in vivo DNA binding assays were used to determine that Pentraxin 3 (PTX3) is a CEBPD responsive gene and serves a protumor role upon anticancer drug treatment. Finally, a PTX3 peptide inhibitor RI37 was developed and assessed the antitumor effects by in vivo assays. RI37 could function as a promising inhibitor for preventing cancer progression and the metastasis, invasion and progression of drug-resistant cancers. The identification of PTX3 provided a new insight in the interaction between host and tumor and the RI37 peptide showed a great opportunity to largely reduce the risk of invasion and metastasis of cancer and drug-resistant cancers.