Switching of pyruvate kinase isoform L to M2 promotes metabolic reprogramming in hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is an aggressive tumor, with a high mortality rate due to late symptom presentation and frequent tumor recurrences and metastasis. It is also a rapidly growing tumor supported by different metabolic mechanisms; nevertheless, the biological and molecular mechanisms involved in the metabolic reprogramming in HCC are unclear. In this study, we found that pyruvate kinase M2 (PKM2) was frequently over-expressed in human HCCs and its over-expression was associated with aggressive clinicopathological features and poor prognosis of HCC patients. Furthermore, knockdown of PKM2 suppressed aerobic glycolysis and cell proliferation in HCC cell lines in vitro. Importantly, knockdown of PKM2 hampered HCC growth in both subcutaneous injection and orthotopic liver implantation models, and reduced lung metastasis in vivo. Of significance, PKM2 over-expression in human HCCs was associated with a down-regulation of a liver-specific microRNA, miR-122. We further showed that miR-122 interacted with the 3UTR of the PKM2 gene. Re-expression of miR-122 in HCC cell lines reduced PKM2 expression, decreased glucose uptake in vitro, and suppressed HCC tumor growth in vivo. Our clinical data and functional studies have revealed a novel biological mechanism involved in HCC metabolic reprogramming.published_or_final_versio

Chinese beliefs in luck are linked to gambling problems via strengthened cognitive biases:A mediation test

10.1007/s10899-017-9690-6Journal of gambling studies3341325-133

Hypoxia Inducible Factor-1 (Hif-1)/ Ectonucleoside Triphosphate Diphosphohydrolase 2 (Entpd2) Maintained an Immune-Suppressive Microenvironment in Hepatocellular Carcinoma

Oral Presentation - General Session 1: Molecular Pathogenesis: no. O-009Introduction: Mortality rate of hepatocellular carcinoma (HCC) is extremely high due to late symptom presentation and lack of curative therapy. Understanding the biology of HCC will accelerate the development of more effective therapies. Hypoxia (Oxygen O2 deprivation) is frequently found in regions of HCC due to abnormal tumor vasculature. Methods: To study the effects of hypoxia on HCC cells, transcriptome sequencing of 6 human HCC cell lines exposed to 20% O2 and 1% O2 conditions and 16 pairs HCC and non-tumourous liver tissues were performed. An ectoenzyme, ectonucleoside triphosphate diphosphohydrolase 2 (ENTPD2/ CD39L1), was found to be consistently upregulated by hypoxia and over-expressed in HCC. ChIP assay confirmed the binding of HIF-1 to ENTPD2. ENTPD2 expression was evaluated in HIF-knockdown or knockout HCC cells established by shRNA or CRISPR-Cas9 approach. ENTPD2 knockdown and knockout HCC cells were established for functional studies. Liquid Chromatography-Mass Spectrometry (LC-MS) was employed to quantitate the level of extracellular metabolites (ATP, AMP) in the ENTPD2 knockdown or knockout HCC subclones. To study the functions of extracellular AMP in myeloid-derived suppressor cells (MDSCs), we purified MDSCs from HCC-bearing mice by magnetic bead sorting followed by in vitro culturing in the presence of absence of AMP. Syngeneic and hepatocarcinogen-induced mouse HCC models were employed to evaluate the effects of the HIF-1/ENTPD2 pathway in HCC. ENTPD2 inhibitors were used alone or in combination with immune therapies (anti-CTLA4 and anti-PD1) in HCC-bearing mice. Results: We first showed that hypoxia, through stabilizing hypoxia-inducible factor 1 (HIF-1), transcriptionally activated an ectoenzyme, ectonucleoside triphosphate diphosphohydrolase 2 (ENTPD2/ CD39L1) in HCC cells. We confirmed that ENTPD2 on hypoxic HCC cells hydrolyzes extracellular ATP to AMP, thereby preventing the differentiation of a population of immunesuppressive cells, MDSCs, and maintaining them in the tumor niche. Co-culturing of HCC-associated MDSCs with CFSE-labelled T cells revealed that MDSCs directly inhibited T cell proliferation. In vivo, we showed that knockdown or knockout of ENTPD2 in HCC cells reduced MDSC accumulation and increased T cell infiltration within the tumors. ENTPD2 inhibitors, POM1 and ARL67156, significantly reduced the number of tumor-associated MDSCs and repressed HCC progression in vivo. More excitingly, ENTPD2 inhibitor worked in synergy with anti-CTLA4 and anti-PD1 monoclonal antibodies to suppress HCC progression in mice. Clinically, we further found that ENTPD2 was frequently over-expressed in human HCC. IHC staining showed that MDSCs were preferentially found in hypoxic regions. Upregulation of ENTPD2 was found to be associated with poor aggressive HCC clinicopathological features such as presences of direct liver invasion, tumor microsatellite formation, and venous invasion, as well as absence of tumor encapsulation. Upregulation of ENTPD2 was also associated with shorter survivals in HCC patients. Conclusion: Our study indicates that ENTPD2 might be a good prognostic marker and therapeutic targets especially for HCC patients who are considering immune checkpoint inhibitors. Our study also reveals a novel molecular mechanism by which hypoxia maintains MDSCs at the tumor niche through HIF-1/ENTPD2 by AMP generation, thereby allowing cancer cells to escape immunosurveillance. Our study also highlights how the external microenvironment (hypoxia) affects metabolism and immunity of HCC

Hepatitis transactivator protein X promotes extracellular matrix modification through HIF/LOX pathway in liver cancer

2017-2018 > Academic research: refereed > Publication in refereed journal201810 bcrcVersion of RecordPublishe