Deguang Sun

Metformin reverses multidrug resistance in human hepatocellular carcinoma Bel‑7402/5‑fluorouracil cells

Metformin exhibits anti-proliferative effects in tumor cells in vitro and in vivo. The present study investigated the ability of metformin to reverse multidrug resistance (MDR) in human hepatocellular carcinoma Bel-7402/5-fluorouracil (5-Fu; Bel/Fu) cells. The synergistic anti-proliferative effect of metformin combined with 5-Fu was evaluated using a Cell Counting kit-8 assay. The variation in apoptotic rates and cell cycle distribution were evaluated using a flow cytometric assay and variations in target gene and protein expression were monitored using reverse transcription-polymerase chain reaction and western blot analysis. The results demonstrated that metformin had a synergistic anti-proliferative effect with 5-Fu in the Bel/Fu cells. The variations in the number of apoptotic cells and distribution of the cell cycle were consistent with the variability in cell viability. Metformin targeted the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway, suppressed the expression of hypoxia-inducible factor-1α (HIF-1α) and transcriptionally downregulated the expression of multidrug resistance protein 1/P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1). Collectively, these findings suggested that metformin may target the AMPK/mTOR/HIF-1α/P-gp and MRP1 pathways to reverse MDR in hepatocellular carcinoma.

Metformin sensitizes hepatocellular carcinoma to arsenic trioxide-induced apoptosis by downregulating Bcl2 expression

Hepatocellular carcinoma (HCC) is a highly malignant tumor that can evolve rapidly to acquire resistance to conventional chemotherapies. Arsenic trioxide (ATO) is a traditional Asian medicine, and a phase II study has shown that treatment with ATO alone was not effective against HCC. Bcl2 is an antiapoptotic protein that regulates chemotherapy in HCC. Metformin is reported to decrease Bcl2 expression, and the purpose of this study was to verify whether metformin could potentiate the anti-HCC efficacy of ATO in vitro. In the present study, we used metformin and ATO alone or in combination and then tested proliferation, apoptosis, and Bcl2 level of HCC cells. The results showed that metformin enhanced both the proliferation-inhibiting and apoptosis-inducing effects of ATO on HCC cell lines HepG2 and BEL7402. Furthermore, this activity proceeded via a mechanism involving metformin-induced downregulation of Bcl2. A combination of ATO and metformin is therefore a potentially promising approach for HCC therapy.

Nogo-B receptor promotes the chemoresistance of human hepatocellular carcinoma via the ubiquitination of p53 protein.

Nogo-B receptor (NgBR), a type I single transmembrane domain receptor is the specific receptor for Nogo-B. Our previous work demonstrated that NgBR is highly expressed in breast cancer cells, where it promotes epithelial mesenchymal transition (EMT), an important step in metastasis. Here, we show that both in vitro and in vivo increased expression of NgBR contributes to the increased chemoresistance of Bel7402/5FU cells, a stable 5-FU (5-Fluorouracil) resistant cell line related Bel7402 cells. NgBR knockdown abrogates S-phase arrest in Bel7402/5FU cells, which correlates with a reduction in G1/S phase checkpoint proteins p53 and p21. In addition, NgBR suppresses p53 protein levels through activation of the PI3K/Akt/MDM2 pathway, which promotes p53 degradation via the ubiquitin proteasome pathway and thus increases the resistance of human hepatocellular cancer cells to 5-FU. Furthermore, we found that NgBR expression is associated with a poor prognosis of human hepatocellular carcinoma (HCC) patients. These results suggest that targeting NgBR in combination with chemotherapeutic drugs, such as 5-FU, could improve the efficacy of current anticancer treatments.

Embelin-induced apoptosis of HepG2 human hepatocellular carcinoma cells and blockade of HepG2 cells in the G2/M phase via the mitochondrial pathway

Embelin is a small-molecule inhibitor extracted from plants of the Myrsinaceae family demonstrating specific inhibition of the X-linked inhibitor of apoptosis protein (XIAP) to affect the proliferation and apoptosis of various types of tumor cells. However, the mechanism of action for this effect remains unclear. The purpose of the present study was to investigate the role of the mitochondrial pathway in embelin-induced HepG2 human hepatocellular carcinoma cell apoptosis and the effect of embelin on the cell cycle. HepG2 human hepatocellular carcinoma cells were treated with different doses of embelin. The MTT method was used to determine cell viability, and flow cytometry was used to assess the rate of apoptosis and the changes in mitochondrial membrane potential; the cell cycle was also analyzed. Western blot analysis was performed to determine the expression levels of the apoptosis-associated proteins Bax, Bcl-2 and the caspase family. The results revealed that embelin induced the apoptosis of the HepG2 cells in a dose- and time-dependent manner. In addition, embelin caused changes in mitochondrial membrane potential. Flow cytometric analysis demonstrated that embelin caused blockade of the HepG2 cells in the G2/M phase of the cell cycle.

Mixed acinar-endocrine carcinoma of pancreas: A case report and brief review of the literature

Mixed acinar-endocrine carcinoma (MAEC) of the pancreas is a rare entity. We present a 65-year-old Chinese female who was admitted with jaundice and nagging epigastric pain with intermittent diarrhea for 1 month. She eventually underwent abdominal magnetic resonance imaging, which showed an 8×6 cm mass in the head of the pancreas and showed two abnormal lesions in the liver simultaneously. MAEC of the pancreas with synchronous hepatic metastasis was confirmed with immunohistochemistry after Whipple operation and hepatic partial resection of the lesions. Postoperative recovery of this patient was uneventful, and no evidence of recurrence or metastasis was observed after 12 months of follow-up. MAEC of pancreas is thought to be extremely rare and lack of typical clinical symptoms. The prognosis is poor overall, but early detection with complete resection may be beneficial to patients.

Traditional Chinese medicine, Qing Ying Tang, ameliorates the severity of acute lung injury induced by severe acute pancreatitis in rats via the upregulation of aquaporin‑1

Aquaporin-1 (AQP-1) is expressed in lung endothelial cells and regulates water transport; thus, AQP-1 plays an important role in a number of edema-associated lung diseases. Qing Yin Tang (QYT), a traditional Chinese medicine, has been shown to effectively reduce the mortality rate of acute lung injury (ALI) induced by severe acute pancreatitis (SAP). The current study aimed to investigate the detailed mechanisms underlying the effects of QYT on ALI induced by SAP, particularly the effects on the expression levels of AQP-1 in the lung tissue. ALI was established in Wister rats who were subsequently divided into four groups: SHAM, ALI, dexamethasone (DEX) and QYT groups (n=8 per group). In the QYT group, 20 ml/kg QYT was administered by gavage immediately following the induction of SAP. Blood and lung tissues were collected 8 h following the induction of pancreatitis. The lung wet/dry ratio, as well as the levels of blood gases, serum amylase and tumor necrosis factor-α (TNF-α), were measured at 4, 8 and 12 h following SAP-associated ALI induction surgery. The expression levels of AQP-1 in the lung tissue were detected by quantitative polymerase chain reaction, immunohistochemistry and western blot analysis. No statistically significant differences were observed with regard to the levels of serum amylase, wet/dry ratio, partial pressure of oxygen, serum TNF-α and pathological changes in the pulmonary tissue between the QYT and DEX groups; however, a statistically significant difference was observed when compared with the ALI group. The expression levels of AQP-1 significantly increased (P<0.05) and lung edema was alleviated in the QYT and DEX groups, when compared with ALI group. Therefore, the expression level of AQP-1 is associated with pulmonary edema. QYT protects the lungs from injury induced by SAP via the upregulation of AQP-1, which suppresses TNF-α expression.

Metformin mediates resensitivity to 5-fluorouracil in hepatocellular carcinoma via the suppression of YAP

Metformin plays an anti-proliferative role in tumor cells in many types of cancer. However, the correlation between metformin and sensitivity to chemotherapeutic agents in hepatocellular carcinoma (HCC) and the relevant mechanism are unclear. The present study showed that HCC patients with type 2 diabetes mellitus benefited from metformin administration, with a longer overall survival. Metformin resensitized Bel-7402/5-fluorouracil (Bel/Fu) cells to 5-fluorouracil (5-Fu) in vitro and in vivo, and the combination of metformin and 5-Fu inhibited cell proliferation, promoted cell apoptosis and induced G0/G1 cell cycle arrest in the Bel/Fu cells. Moreover, metformin repressed YAP by both decreasing the total protein expression and accelerating the phosphorylation of YAP. The inhibition of YAP subsequently promoted the expression of PTEN, and suppressed the Akt pathway. Therefore, the expression of P-gp and MRP1 was downregulated. Taken together, our findings suggested that metformin may increase sensitivity to chemotherapeutic agents by suppressing YAP in hepatocellular carcinoma.

Long Non-Coding RNA Linc-USP16 Functions As a Tumour Suppressor in Hepatocellular Carcinoma by Regulating PTEN Expression

Background/Aims: Recent evidence has indicated the crucial regulatory roles of long non-coding RNAs (lncRNAs) in tumour biology. In hepatocellular carcinoma (HCC), aberrant expression of lncRNAs plays an essential role in HCC tumourigenesis. However, the potential roles and regulatory mechanisms of the novel human lncRNA, Linc-USP16, in HCC are unclear. Methods: To investigate the function of Linc-USP16 in HCC, we first analysed the expression levels of Linc-USP16 in HCC patient tissues and cell lines via q-RT-PCR and established overexpressed or knockdown HCC cell lines. Results: Here, we found that Linc-USP16 expression was significantly down-regulated in HCC patient tissues and cell lines. Further functional experiments suggested that Linc-USP16 could directly increase PTEN expression by acting as a competing endogenous RNA (ceRNA) for miR-21 and miR-590-5p. These interactions led to repression of AKT pathway and inhibition of HCC cell proliferation and migration. Conclusion: Thus, our data showed that Linc-USP16, as a tumour suppressor, plays an important role in HCC pathogenesis and provides a new therapeutic strategy for HCC treatment.

Growing Teratoma Syndrome Secondary to Ovarian Giant Immature Teratoma in an Adolescent Girl: A Case Report and Literature Review

AbstractGrowing teratoma syndrome (GTS) is a rare clinical entity first described by Logothetis et al in 1982. Although it is unusual for GTS to be located in the ovary, this report is of a case of an adolescent girl who underwent a complete surgical resection of the mass. Histopathology confirmed only an immature teratoma had originated from the ovary and so she received adjuvant chemotherapy with blemycin, etopside, and cisplatin over 4 cycles. Results from an abdominal enhanced CT (computed tomography) 9 years later revealed a giant mass had compressed adjacent tissues and organs. Laparotomy was performed and a postoperative histopathology showed the presence of a mature teratoma, and so the diagnosis of ovarian GTS was made. One hundred one cases of ovarian GTS from English literature published between 1977 and 2015 were collected and respectively analyzed in large samples for the first time.The median age of diagnosis with primary immature teratoma was 22 years (range 4–48 years, n = 56). GTS originating from the right ovary accounted for 57% (27/47, n = 47) whereas the left contained 43% (20/47, n = 47). Median primary tumor size was 18.7 cm (range 6–45 cm, n = 28) and median subsequent tumor size was 8.6 cm (range 1–25 cm, n = 25). From the primary treatment to the diagnosis of ovarian GTS, median tumor growth speed was 0.94 cm/month (range 0.3–4.3 cm/month, n = 21). Median time interval was 26.6 months (range 1–264 months, n = 41). According to these findings, 5 patients did have a pregnancy during the time interval between primary disease and GTS, making our patient the first case of having a pregnancy following the diagnosis of ovarian GTS. Because of its high recurrence and insensitiveness to chemotherapy, complete surgical resection is the preferred treatment and fertility-sparing surgery should be considered for women of child-bearing age.Anyhow GTS of the ovary has an excellent prognosis. Patients with GTS had no evidence of recurrence or were found to be disease free during a 40.3-month (range 1–216 months, n = 48) median follow-up. Moreover, regular follow-ups with imaging and serum tumor markers are important and must not be neglected.

Melatonin enhances the anti-tumor effect of sorafenib via AKT/p27-mediated cell cycle arrest in hepatocarcinoma cell lines

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide, often diagnosed in late stages when most therapeutic methods are not very effective. The introduction of the multikinase inhibitor sorafenib as the standard of care has opened a window of hope for patients with advanced HCC, patients with very poor prognosis; however, patients usually develop acquired resistance to sorafenib limiting its therapeutic benefits. Melatonin (MT), an indoleamine compound produced in the pineal gland, has shown a substantial beneficial effect in increasing the efficacy of common anticancer drugs and decreasing their toxic effects. Here we demonstrate that MT potentiated the sorafenib-mediated inhibition of cell viability and colony formation in HCC cell lines. Moreover, combined treatment of MT and sorafenib enhanced the cell cycle arrest of HCC cells at the G0/G1 phase. Co-treatment of sorafenib and MT was found to upregulate p27, an inhibitor of several cyclin-dependent kinases (CDK), and downregulate p-AKT, c-myc, cyclin D1 and CDK4/6 protein expression. Furthermore, overexpression of p-AKT using SC79 reversed the effect of sorafenib and MT combination on cell viability and growth of HCC cells. These results suggest that the AKT pathway might be critical for the enhanced anticancer effect observed after co-treatment with MT and sorafenib. Taken together, our findings demonstrated that AKT/p27-mediated cell growth arrest induced by MT increased the sensitivity of HCC cells to the effect of sorafenib.