Novel STAT3 oligonucleotide compounds suppress tumor growth and overcome the acquired resistance to sorafenib in hepatocellular carcinoma.

Signal transducer and activator of transcription 3 (STAT3) plays an important role in the occurrence and progression of tumors, leading to resistance and poor prognosis. Activation of STAT3 signaling is frequently detected in hepatocellular carcinoma (HCC), but potent and less toxic STAT3 inhibitors have not been discovered. Here, based on antisense technology, we designed a series of stabilized modified antisense oligonucleotides targeting STAT3 mRNA (STAT3 ASOs). Treatment with STAT3 ASOs decreased the STAT3 mRNA and protein levels in HCC cells. STAT3 ASOs significantly inhibited the proliferation, survival, migration, and invasion of cancer cells by specifically perturbing STAT3 signaling. Treatment with STAT3 ASOs decreased the tumor burden in an HCC xenograft model. Moreover, aberrant STAT3 signaling activation is one of multiple signaling pathways involved in sorafenib resistance in HCC. STAT3 ASOs effectively sensitized resistant HCC cell lines to sorafenib in vitro and improved the inhibitory potency of sorafenib in a resistant HCC xenograft model. The developed STAT3 ASOs enrich the tools capable of targeting STAT3 and modulating STAT3 activity, serve as a promising strategy for treating HCC and other STAT3-addicted tumors, and alleviate the acquired resistance to sorafenib in HCC patients. A series of novel STAT3 antisense oligonucleotide were designed and showed potent anti-cancer efficacy in hepatocellular carcinoma in vitro and in vivo by targeting STAT3 signaling. Moreover, the selected STAT3 ASOs enhance sorafenib sensitivity in resistant cell model and xenograft model.

Human augmenter of liver regeneration is important for hepatoma cell viability and resistance to radiation-induced oxidative stress.

To gain new insight into the biological function of the human augmenter of liver regeneration (hALR) in HCC, we studied its involvement in radiation-induced damage and recovery of HCC cells. We found that hALR expression was up-regulated in both HCC tissues and multiple hepatoma cell lines and correlated significantly with increased radiation clonogenic survival after radiation treatment. Exogenous expression of hALR increased radiation resistance in SMMC-7721 cells, and the increased survival was accompanied by a decrease in apoptosis and a prolonged G(2)-M arrest after irradiation. Overexpression of ALR significantly increased the mitochondrial membrane potential, inhibited cytochrome c release, and opposed the loss of intracellular ATP levels after radiation. Moreover, knockdown of ALR by siRNA resulted in inhibition of viability in the absence of exogenously added oxidative stress and radiation sensitization in HepG2 cells. Importantly, hALR expression was very low in normal hepatocyte L02 cells, and hALR silencing had a minimal effect on L02 viability and radiation sensitivity. These results suggest that human ALR is important for hepatoma cell viability and involved in the protection of hepatoma cells against irradiation-induced damage by its association with mitochondria. Targeting hALR may be a promising novel approach to enhance the radiosensitivity of hepatoma cancers.

[Efficient expression of exogenous human gp96 gene in tumor cells].

BACKGROUND & OBJECTIVE: Immunization of mice with preparations of heat shock protein(HSP) gp96 isolated from cancer cells has been shown to elicit specific protective cytotoxic T lymphocyte response against cells from which gp96 originate. This phenomenon exploits a new practicable pathway for cancer immunotherapy. But gp96 is generally expressed at low level in cells. Gp96 preparations from limited cells or tissue are difficult to meet the needs of study. So the current study aims to acquire minoclonal cell lines expressing gp96 at high level in order to prepare enough gp96 with high quality. METHODS: The recombinant plasmid pcDNA-hgp96 of human gp96 cDNA was constructed by ligating the fragment of gp96 cDNA into the pcDNA3 plasmid, a eucaryotic expressing vector. Then the recombinant plasmid was transfected into Hela cells and the stable transfectants were selected with G418. The expression level of gp96 of the positive monoclonal cells was detected by Western blot analysis. RESULTS: The recombinant expression plasmid of human gp96 cDNA was successfully constructed. The monoclonal cell lines with stable transfection were obtained. A monoclonal cell line expressing gp96 on high level was selected out. CONCLUSIONS: The monoclonal cell line expressing gp96 at high level has been successfully established, which lays the groundwork for the study of its antitumor immunity.