Shaojun Liu

miR-124 and miR-506 inhibit colorectal cancer progression by targeting DNMT3B and DNMT1.

miR-124 and miR-506 are reportedly down-regulated and associated with tumor progression in many cancers, but little is known about their intrinsic regulatory mechanisms in colorectal cancer (CRC). In this study, we found that the miR-124 and miR-506 levels were significantly lower in human CRC tissues than in controls, as indicated by qRT-PCR and in situ hybridization histochemistry. We also found that the overexpression of miR-124 or miR-506 inhibited tumor cell progression and increased sensitivity to chemotherapy in vitro. Increased miR-124 or miR-506 expression also inhibited tumor cell proliferation and invasion in vivo. Luciferase reporter assays and western blotting were used to determine the association between miR-124, miR-506 and their target genes, DNMTs. We further identified that miR-124 and miR-506 directly targeted DNMT3B and indirectly targeted DNMT1. The overexpression of miR-124 and miR-506 reduced global DNA methylation and restored the expression of E-cadherin, MGMT and P16. In conclusion, our data showed that miR-124 and miR-506 inhibit progression and increase sensitivity to chemotherapy by targeting DNMT3B and DNMT1 in CRC. These findings may provide novel avenues for the development of targeted therapies.

Infliximab enhances the therapeutic effects of 5-fluorouracil resulting in tumor regression in colon cancer

Colon cancer (CC) is among the most common malignant diseases with a dismal survival. Tumor necrosis factor-alpha (TNF-α) has been identified as a therapeutic target in various cancers, and anti-TNF-α treatment has shown promising effects in different cancer models. However, if TNF-α can be targeted in CC, the therapeutic values of anti-TNF-α treatment in CC remain unknown. Our study indicated that TNF-α is highly expressed in CC cell lines and patient tumor samples. High expression of TNF-α is an independent adverse prognosticator of CC. Targeting the TNF-α by its antibody infliximab induced antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity and enhanced apoptosis leading to cell death. The combination of infliximab with 5-fluorouracil showed better responses in vitro and in vivo than 5-fluorouracil alone. In conclusion, this study identified TNF-α as a target of CC and anti-TNF-α treatment synergized with chemotherapy leading to a better outcome in preclinical models.

miR-142-5p promotes development of colorectal cancer through targeting SDHB and facilitating generation of aerobic glycolysis

Aberrant expression of miRNAs contributes to the development of human malignancies. A recent study revealed that miR-142-5p is increased in the serum of colorectal cancer (CRC) patients compared to health people. Using starBase v2.0, we found that succinate dehydrogenase-B (SDHB) is a potential target of miR-142-5p, while SDHB is negatively correlated to cancer development through regulating energetic metabolism. Based on these information, this study further examined the expression profiles of miR-142-5p and SDHB in CRC tissues and cell lines using PCR and Western blotting. Transfection experiment and luciferase assay were performed to identify relationship between miR-142-5p and SDHB. Oxygen intake, glucose consumption and production of lactic acid were used to evaluate the influence on energetic metabolism. CRC growth and proliferation were assessed by in vitro and in vivo studies. Results showed that miR-142-5p was up-regulated in CRC, but SDHB was down-regulated. SDHB was confirmed as a target of miR-142-5p, and decreased SDHB in CRC was result from the abnormal up-regulation of miR-142-5p. Lose of SDHB by miR-142-5p inhibited oxygen intake by CRC cells, but increased glucose consumption and lactate production. These suggest miR-142-5p up-regulation in CRC probably facilitates generation of aerobic glycolysis by reducing SDHB. miR-142-5p promoted proliferation and colony formation of CRC, but inhibited apoptosis. SDHB overexpression abrogated these effect of miR-142-5p, which indicates that SDHB depletion mediates tumor-promoting actions of miR-142-5p. This study added novel insight into the CRC development regulated by miR-142-5p. It may be a promising therapy target in the future molecular therapy.

Cronkhite‑Canada syndrome: A case report

Cronkhite-Canada syndrome (CCS) is a rare non-inherited condition characterized by gastrointestinal (GI) hamartomatous polyposis, alopecia, onychodystrophy, hyperpigmentation, weight loss and diarrhea. The etiology is most likely autoimmune and diagnosis is based on patient history, physical examination, endoscopic findings of GI polyposis and histology. The disease is very rare; thus far more than 500 cases of CCS have been reported globally. A 58-years-old male with CCS was reported in the present case study. The patient experienced a history of diarrhea and hematochezia for 4 months, with abdominal pain for 1 month and additional nail and toenail loss for half a month. The clinical, endoscopic and histological data confirmed the diagnosis.

SDHB downregulation facilitates the proliferation and invasion of colorectal cancer through AMPK functions excluding those involved in the modulation of aerobic glycolysis

Loss-of-function of succinate dehydrogenase-B (SDHB) is a predisposing factor of aerobic glycolysis and cancer progression. Adenosine monophosphate activated protein kinase (AMPK) is involved in the regulation of aerobic glycolysis and the diverse hallmarks of cancer. The present study investigated whether AMPK mediated the regulatory effects of SDHB in aerobic glycolysis and cancer growth. The expression of SDHB and AMPK in colorectal cancer (CRC) and normal tissues was assessed by western blotting. HT-29 CRC cells were used to establish in vitro models of ectopic overexpression and knockdown of SDHB. SDHB was downregulated, while AMPK and phosphorylated-AMPK (Thr172) were upregulated in CRC tissues. Experiments involving the loss- or gain-of-function of SDHB, revealed that this protein negatively regulated AMPK by influencing its expression and activity. However, SDHB and AMPK were identified to suppress lactic acid production in CRC cells, indicating that each had an inhibitory effect on aerobic glycolysis. Therefore, the regulation of aerobic glycolysis by SDHB is unlikely to be mediated via AMPK. SDHB knockdown promoted the viability, migration and invasion of HT-29 cells, whereas inhibition of AMPK demonstrated the opposite effect. SDHB overexpression impaired cell migration and invasion, and this effect was reversed following AMPK activation. These results indicate that AMPK may mediate the effects of SDHB in CRC cell proliferation and migration. In conclusion, SDHB downregulation in CRC cells may increase AMPK activity, which may subsequently facilitate the proliferation and invasion of these cancer cells. However, the regulation of aerobic glycolysis by SDHB may be independent of AMPK. Further studies are warranted to elucidate the mechanism by which SDHB regulates aerobic glycolysis.

Study on protective effect of extract on hepatic ischemia-reperfusion injury

The objective of the study was to study the protective effect of Silybum marianum extract on hepatic ischemiareperfusion injury. Rats were randomly divided into five groups; namely Silybum marianum extract high-, medium-, and lowdose protection groups, model group and control group. Hepatic ischemia-reperfusion injury model was prepared. Serum or plasma AST, ALT, MDA, TNF-α, IL-1β, IL-6 levels were measured. The results revealed that after liver injury, AST, ALT, MDA, TNF-α, IL-1β, and IL-6 levels significantly increased in succession, showing significant differences. We concluded that inflammatory cytokines participate in liver injury and that Silybum marianum extract can reduce the production of inflammatory cytokines, and thus can have a protective effect on hepatic ischemia and reperfusion. Keywords : Silybum marianum , hepatic ischemia-reperfusion injury, protective effect