mascRNA and its parent lncRNA MALAT1 promote proliferation and metastasis of hepatocellular carcinoma cells by activating ERK/MAPK signaling pathway.

MALAT1-associated small cytoplasmic RNA (mascRNA) is a cytoplasmic tRNA-like small RNA derived from nucleus-located long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1). While MALAT1 was extensively studied and was found to function in multiple cellular processes, including tumorigenesis and tumor progression, the role of mascRNA was largely unknown. Here we show that mascRNA is upregulated in multiple cancer cell lines and hepatocellular carcinoma (HCC) clinical samples. Using HCC cells as model, we found that mascRNA and its parent lncRNA MALAT1 can both promote cell proliferation, migration, and invasion in vitro. Correspondingly, both of them can enhance the tumor growth in mice subcutaneous tumor model and can promote metastasis by tail intravenous injection of HCC cells. Furthermore, we revealed that mascRNA and MALAT1 can both activate ERK/MAPK signaling pathway, which regulates metastasis-related genes and may contribute to the aggressive phenotype of HCC cells. Our results indicate a coordination in function and mechanism of mascRNA and MALAT1 during development and progress of HCC, and provide a paradigm for deciphering tRNA-like structures and their parent transcripts in mammalian cells.

Efficacy of cytokine-induced killer cell-based immunotherapy for hepatocellular carcinoma.

In attempts to delay tumor progression after surgery or minimally invasive local treatments, multidisciplinary strategies have been broadly studied in patients with hepatocellular carcinoma (HCC). The objective of this present study was to evaluate the efficacy of autologous transplantations of cytokine-induced killer (CIK) cells as an adjuvant therapy for patients with HCC. A total of 264 patients with HCC were enrolled in this retrospective study. Of these patients, 165 received either CIK cell therapy alone or as adjuvant therapy to surgery, transcatheter arterial chemoembolization (TACE), or TACE-based comprehensive treatments (CT). The remaining 99 patients received only surgery or TACE. Kaplan-Meier analysis and the Chi-squared test were used to analyze the overall survival (OS), progression-free survival (PFS), and clinical characteristics of the patients in the different treatment subgroups. Kaplan-Meier analysis suggested that patients in the Surgery+CIK group had a significantly improved OS compared with those in the other three groups (P < 0.001). Furthermore, patients who developed a fever after the CIK cell treatments manifested a likely better OS (P = 0.028). Subgroup analysis indicated that patients in the Surgery+CIK group likely had an improved PFS but a similar OS compared with the patients in the Surgery-alone group (P = 0.055 for PFS, and P = 0.746 for OS). Further subgroup analysis showed that the OS in both the TACE+CIK and CT+CIK groups was prolonged significantly compared with that in the TACE-alone group (P = 0.015 and P = 0.018, respectively). However, similar OS was observed between the TACE+CIK and CT+CIK groups (P = 0.686). Autologous transplantation of CIK cells as an adjuvant therapy was associated with better survival for patients with HCC, especially for those who had also undergone TACE. A fever reaction might be a potential event for assessing the curative effect of the CIK treatment.

The neuroleptic drug pimozide inhibits stem-like cell maintenance and tumorigenicity in hepatocellular carcinoma.

Drug repurposing is currently an important approach for accelerating drug discovery and development for clinical use. Hepatocellular carcinoma (HCC) presents drug resistance to chemotherapy, and the prognosis is poor due to the existence of liver cancer stem-like cells. In this study, we investigated the effect of the neuroleptic agent pimozide to inhibit stem-like cell maintenance and tumorigenicity in HCC. Our results showed that pimozide functioned as an anti-cancer drug in HCC cells or stem-like cells. Pimozide inhibited cell proliferation and sphere formation capacities in HCC cells by inducing G0/G1 phase cell cycle arrest, as well as inhibited HCC cell migration. Surprisingly, pimozide inhibited the maintenance and tumorigenicity of HCC stem-like cells, particularly the side population (SP) or CD133-positive cells, as evaluated by colony formation, sphere formation and transwell migration assays. Furthermore, pimozide was found to suppress STAT3 activity in HCC cells by attenuating STAT3-dependent luciferase activity and down-regulating the transcription levels of downstream genes of STAT3 signaling. Moreover, pimozide reversed the stem-like cell tumorigenic phenotypes induced by IL-6 treatment in HCC cells. Further, the antitumor effect of pimozide was also proved in the nude mice HCC xenograft model. In short, the anti-psychotic agent pimozide may act as a novel potential anti-tumor agent in treating advanced HCC.

Efficient derivation of functional hepatocytes from mouse induced pluripotent stem cells by a combination of cytokines and sodium butyrate.

BACKGROUND: Hepatocyte transplantation has been proposed as an alternative to whole-organ transplantation to support many forms of hepatic insufficiency. Unfortunately, the lack of donor livers makes it difficult to obtain enough viable human hepatocytes for hepatocyte-based therapies. Therefore, it is urgent to find new ways to provide ample hepatocytes. Induced pluripotent stem (iPS) cells, a breakthrough in stem cell research, may terminate these hinders for cell transplantation. For the promise of iPS cells to be realized in liver diseases, it is necessary to determine if and how efficient they can be differentiated into functional hepatocytes. METHODS: In this study, we directly compared the hepatic-differentiation capacity of mouse iPS cells and embryonic stem (ES) cells with three different induction approaches: conditions via embryonic body (EB) formation plus cytokines, conditions by combination of dimethyl sulfoxide and sodium butyrate and chemically defined, serum free monolayer conditions. Among these three induction conditions, more homogenous populations can be promoted under chemically defined, serum free conditions. The cells generated under these conditions exhibited hepatic functions in vitro, including glycogen storage, indocynine green (ICG) uptake and release as well as urea secretion. Although efficient hepatocytes differentiation from mouse iPS cells were observed, mouse iPS cells showed relatively lower hepatic induction efficiency compared with mouse ES cells. RESULTS: Mouse iPS cells would be efficiently differentiated into functional hepatocytes in vitro, which may be helpful in facilitating the development of hepatocytes for transplantation and for research on drug discovery. CONCLUSION: We demonstrate that mouse iPS cells retain full potential for fetal liver development and describe procedures that facilitates the efficient generation of highly differentiated human hepatocyte-like cells from iPS cells in vitro.