Role of gut microbiome in regulating the effectiveness of metformin in reducing colorectal cancer in type 2 diabetes.

The prevalence of colorectal cancer (CRC) and type 2 diabetes mellitus (T2DM) is increasing globally. It is rarely noticed that the incidence of CRC is higher in patients with T2DM. What needs to be mentioned is that metformin, a commonly used clinical drug for T2DM, attracts scholars' attention because of its benefits in lowering the risk of developing CRC. Hence, we try to find the common grounds of initiation of T2DM and CRC and the reason why metformin reduces the risk of CRC in patients with T2DM. We noticed consistent changes of gut microbiota, such as elevated Bacteroides, Prevotella and Bifidobacterium and depressed Firmicutes and Lactobacillus. Furthermore, many studies in recent years have proved that the efficacy of metformin, such as improving blood glucose, depends on the gut microbiota. Coincidentally, the progression of CRC is inseparable from the contributions of gut microbiota. Therefore, we first proposed the concept of the metformin-gut microbiota-CRC (in T2DM) axis to explain the effect of metformin in reducing CRC in patients with T2DM. In this review, we elaborated the new concept and its potential clinical application value.

Synthesis, preliminarily biological evaluation and molecular docking study of new Olaparib analogues as multifunctional PARP-1 and cholinesterase inhibitors.

A series of new Olaparib derivatives was designed and synthesized, and their inhibitory activities against poly (ADP-ribose) polymerases-1 (PARP-1) enzyme and cancer cell line MDA-MB-436 in vitro were evaluated. The results showed that compound 5l exhibited the most potent inhibitory effects on PARP-1 enzyme (16.10 ± 1.25 nM) and MDA-MB-436 cancer cell (11.62 ± 2.15 µM), which was close to that of Olaparib. As a PARP-1 inhibitor had been reported to be viable to neuroprotection, in order to search for new multitarget-directed ligands (MTDLs) for the treatment of Alzheimer's disease (AD), the inhibitory activities of the synthesized compounds against the enzymes AChE (from electric eel) and BChE (from equine serum) were also tested. Compound 5l displayed moderate BChE inhibitory activity (9.16 ± 0.91 µM) which was stronger than neostigmine (12.01 ± 0.45 µM) and exhibited selectivity for BChE over AChE to some degree. Molecular docking studies indicated that 5l could bind simultaneously to the catalytic active of PARP-1, but it could not interact well with huBChE. For pursuit of PARP-1 and BChE dual-targeted inhibitors against AD, small and flexible non-polar groups introduced to the compound seemed to be conducive to improving its inhibitory potency on huBChE, while keeping phthalazine-1-one moiety unchanged which was mainly responsible for PARP-1 inhibitory activity. Our research gave a clue to search for new agents based on AChE and PARP-1 dual-inhibited activities to treat Alzheimer's disease.

The lncRNA PDIA3P Interacts with miR-185-5p to Modulate Oral Squamous Cell Carcinoma Progression by Targeting Cyclin D2.

Long noncoding RNAs (lncRNAs) are emerging as important regulators during tumorigenesis by serving as competing endogenous RNAs (ceRNAs). In this study, the qRT-PCR results indicated that the lncRNA protein disulfide isomerase family A member 3 pseudogene 1 (PDIA3P) was overexpressed in oral squamous cell carcinoma (OSCC) and decreased the survival rate of OSCC patients. CCK-8 and clonal colony formation assays were used to detect the effects of PDIA3P on proliferation. Results revealed that silencing PDIA3P by small interfering RNA (siRNA) inhibited OSCC cell proliferation and repressed tumor growth and reduced the expression of proliferation antigen Ki-67 in vivo. Furthermore, the interaction between PDIA3P and miRNAs was then analyzed by qRT-PCR and luciferase reporter gene assay. We found that PDIA3P negatively regulated miR-185-5p in OSCC cells. Simultaneously, we found that silencing PDIA3P by siRNA suppressed proliferation via miR-185-5p in OSCC cells. Moreover, silencing PDIA3P by siRNA inhibited CCND2 protein (no influence on mRNA levels) expression via miR-185-5p in OSCC cells, and CCND2 facilitated cell proliferation of SCC4 and SCC15 cells induced by sh-PDIA3P#1. Therefore, our study demonstrated that PDIA3P may be a therapeutic target for the treatment of OSCC.

SIRT2 mediated antitumor effects of shikonin on metastatic colorectal cancer.

SIRT2 is involved in the development of a variety of cancers. Shikonin is a natural compound that is known to have antitumor effects. This study aims to assess the effects of shikonin on the development and metastatic progression of colorectal cancer (CRC) through regulation of SIRT2 expression and whether this effect is related to the phosphorylation of extracellular signal-regulated kinases (ERKs). The results demonstrated that SIRT2 is downregulated in CRC biopsy samples (n=31) compared with the adjacent non-cancerous tissues (ANCT, n=26). Furthermore, CRC metastases were positive for SIRT2 despite a lack of expression in the primary tumor. In addition, data from an in vitro assay revealed that overexpression of SIRT2 inhibited the proliferation and metastatic progression of SW480 cells while blocking of SIRT2 expression induced the proliferation and metastatic progression of HT29 cells. Shikonin inhibited the viability, migration and invasion of SW480 cells and it also inhibited the tumor growth in the nude mice model; while AGK2 (a specific inhibitor of SIRT2) reversed these effects. Epidermal growth factor (EGF, an activator of ERK) and ERK-overexpression inhibited the effects of shikonin on SIRT2 expression, proliferation and metastasis in SW480 cells. However, this proliferative effect of EGF was reversed by SIRT2 overexpression. In conclusion, these results suggest that SIRT2 is a new therapeutic target for the treatment of CRC. The antitumor effects of shikonin on CRC seem to be mediated by SIRT2 upregulation via phospho-ERK inhibition.

TrkB activation by 7, 8-dihydroxyflavone increases synapse AMPA subunits and ameliorates spatial memory deficits in a mouse model of Alzheimer's disease.

We recently demonstrated that activation of tyrosine receptor kinase B (TrkB) by 7, 8-dihydroxyflavone (7, 8-DHF), the selective TrkB agonist, increased surface alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors (AMPARs) AMPA receptor subunit GluR1 (GluA1) subunit expression at the synapses of Fragile X Syndrome mutant mice. This present study investigated the effects of 7, 8-DHF on both memory function and synapse structure in relation to the synapse protein level of AMPARs in the Tg2576 Alzheimer's disease (AD) mouse model. The study found that chronic oral administration of 7, 8-DHF significantly improved spatial memory and minimized dendrite loss in the hippocampus of Tg2576 mice. A key feature of 7, 8-DHF action was the increased expression of both GluA1 and GluA2 at synapses. Interestingly, 7, 8-DHF had no effect on the attenuation of amyloid precursor protein or Aß exhibiting in the Tg2576 AD brains, yet it activated the phosphorylation of TrkB receptors and its downstream signals including CaMKII, Akt, Erk1/2, and cAMP-response element-binding protein. Importantly, cyclotraxin B (a TrkB inhibitor), U0126 (a Ras-ERK pathway inhibitor), Wortmannin (an Akt phosphorylation inhibitor), and KN-93 (a CaMKII inhibitor) counteracted the enhanced expression and phosphorylation of AMPAR subunits induced by 7, 8-DHF. Collectively, our results demonstrated that 7, 8-DHF acted on TrkB and resolved learning and memory impairments in the absence of reduced amyloid in amyloid precursor protein transgenic mice partially through improved synaptic structure and enhanced synaptic AMPARs. The findings suggest that the application of 7, 8-DHF may be a promising new approach to improve cognitive abilities in AD. We provided extensive data demonstrating that 7, 8-dihydroflavone, the TrkB agonist, improved Tg2576 mice spatial memory. This improvement is correlated with a reversion to normal values of GluA1 and GluA2 AMPA receptor subunits and dendritic spines in CA1. This work suggests that 7, 8-DHF is a suitable drug to potentiate in vivo Tropomyosin receptor kinase B (TrkB) signaling in the Alzheimer's disease mice model.

Effects of adenovirus-mediated human cyclooxygenase-2 antisense RNA on the growth of hepatocellular carcinoma.

AIM: To investigate the relation between the expression of cyclooxygenase-2 (COX-2) and liver cancer, to construct the recombinant adenovirus encoding human COX-2 antisense RNA, and to explore its effects on liver cancer cell proliferation. METHODS: We studied the expression of COX-2 in 34 cases of hepatocellular carcinoma (HCC) and SMMC7402 and SMMC7721 by immunohistochemical technique. Recombinant adenovirus Ad-AShcox-2 was constructed and transfected into human HCC cell lines SMMC7402 and SMMC7721, and its effects on COX-2 expression, cell apoptosis and cell cycle were analyzed by flow cytometry. Cell proliferation was determined by colony-forming efficiency. RESULTS: We observed COX-2 expression in 82.4% of the HCC and SMMC7402 cells, but no COX-2 expression in SMMC7721 cells. In addition, recombinant adenovirus encoding antisense COX-2 fragment Ad-AShcox-2 was obtained with the titer of 1.06 x 10(12) PFU/mL. Ad-AShcox-2 could reduce the expression of COX-2 and enhance the percentage of cells in G(1)/G(0) phase in SMMC7402 cell line. The difference of apoptotic index between the Ad-AShcox-2 group and control group was statistically significant (t( control group ) = 32.62 and t( Ad-LacZ ) = 10.93, P<0.001) in SMMC7402 but not in SMMC7721. Similarly, colony-forming rates of SMMC7402 and SMMC7721 cell lines, after the transfer of Ad-AShcox-2, were (2.7+/-0.94)% and (33.6+/-4.24)%, respectively. CONCLUSION: Reduction in the expression of COX-2 can inhibit COX-2 expressing HCC cells.

[The effects of adenovirus-mediated human COX-2 antisense RNA on the growth of hepatocellular carcinoma].

OBJECTIVE: To investigate the relationship between the expression of COX-2 and liver cancer and construct a recombinant adenovirus encoding human COX-2 antisense RNA, and then to investigate its effects on liver cancer cell proliferation. METHODS: The expression of COX-2 in 34 cases of hepatocellular carcinoma and in SMMC-7402 and SMMC-7721 cell lines was studied by using immunohistochemical techniques. The shuttle plasmid encoding anti-sense COX-2 was constructed by using cloning COX-2 cDNA fragment in the reverse direction into the pHCMVSPIA. Then the plasmid pJM17 and the shuttle plasmid were co-transferred into 293 cells with lipofectamine for homologous recombination to acquire recombinant adenovirus (Ad-AShcox-2), which was confirmed by PCR. Human hepatocellular carcinoma cell lines SMMC-7402 and SMMC-7721 were transduced in vitro. The cell apoptosis and cell cycle were analyzed by flow cytometry. The cell proliferation was determined by colony-forming efficiency. RESULTS: We observed COX-2 expression in 82.4% of the hepatocellular carcinomas and SMMC-7402 cell line, but no COX-2 expression in the SMMC-7721 cell line. In addition, the recombinant adenovirus encoding anti-sense COX-2 fragment Ad-AShcox-2 was obtained with a titer of 1.06 x 10(12) PFU/ml. Ad-AShcox-2 reduced the expression of COX-2 and enhanced the percentage of cells into G1/G0 phase in the SMMC-7402 cell line. The difference of apoptotic index between the Ad-AShcox-2 group and the control group was statistically significant in SMMC-7402 but not in SMMC-7721. Similarly, colony-forming rates of SMMC-7402 and SMMC-7721 cell lines after Ad-AShcox-2 being transferred were (2.7+/-0.94)% and (33.6+/-4.24)%, respectively. CONCLUSION: By reducing the expression of COX-2 in hepatocellular carcinoma cells with the expression of COX-2, the cells could be inhibited.

Adenovirus expressing p27kip1 suppresses growth of established esophageal carcinoma xenografts.

AIM: To investigate the growth suppression of adenovirus expressing p27(kip1) on established esophageal tumors in nude mice. METHODS: Esophageal carcinoma xenografts in nude mice were established by tumor tissue mass transplantation. The successfully constructed recombinant adenoviral vectors carrying p27(kip1) gene (Ad-p27(kip1)) were directly injected into the esophageal tumors in nude mice. Compared to control group, the growth curve of tumor was drawn and the growth inhibition rate of tumor was calculated. The histology of tumors was examined by hematoxylin and eosin (H&E) staining. The expression of p27(kip1) and survivin was detected in tumors by immunohistochemical technique. RESULTS: The growth of tumors in gene therapy group with Ad-p27(kip1) was obviously suppressed compared to control group (0.42+/- 0.08 g vs 1.17+/- 0.30 g, t=6.39, P< 0.01), the inhibition rate of tumor growth reached 64.1%. Pathological detection showed that the tumors in nude mice were poorly differentiated esophageal squamous carcinoma. In addition, the expression of p27(kip1) was increased, while the expression of survivin was decreased in tumors after being transfected with Ad-p27(kip1). CONCLUSION: p27(kip1) gene therapy mediated by adenovirus vector has a significant inhibitory effect on esophageal carcinoma in vivo. Up-regulated p27(kip1) expression and down-regulated survivin expression may be its important mechanisms.

Inhibitory effect of ubiquitin-proteasome pathway on proliferation of esophageal carcinoma cells.

AIM: To investigate the inhibitory effect of ubiquitin-proteasome pathway (UPP) on proliferation of esophageal carcinoma cells. METHODS: Esophageal carcinoma cell strain EC9706 was treated with MG-132 to inhibit its UPP specificity. Cell growth suppression was evaluated with 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. DNA synthesis was evaluated by (3)H-thymidine ((3)H-TdR) incorporation. Morphologic changes of cells were observed under microscope. Activity of telomerase was examined by telomeric repeat amplification protocol (TRAP) of PCR-ELISA. Cell cycle and apoptosis were detected by flow cytometry (FCM). DNA fragment analysis was used to confirm the presence of apoptosis. Expression of p27(kip1) was detected by immunocytochemical technique. RESULTS: After exposed to MG-132, the growth and value of (3)H-TdR incorporation of EC9706 cells were obviously inhibited. Cells became round, small and exfoliative under microscope. TRAP PCR-ELISA showed that light absorption of cells gradually decreased after exposed to 5 micromol/L of MG-132 for 24, 48, 72 and 96 h (P<0.01). The percentage of cells at G(0)/G(1) phase was increased and that at S and G(2)/M was decreased (P<0.01). The rate of apoptotic cells treated with 5 micromol/L of MG-132 for 48 and 96 h was 31.7% and 66.4%, respectively. Agarose electrophoresis showed marked ladders. In addition, the positive signals of p27(kip1) were located in cytoplasm and nuclei in MG-132 group in contrast to cytoplasm staining in control group. CONCLUSION: MG-132 can obviously inhibit proliferation of EC9706 cells and induce apoptosis. The mechanisms include upregulation of p27(kip1) expression, G(1) arrest and depression of telomerase activity. The results indicate that inhibiting UPP is a novel strategy for esophageal carcinoma therapy.

Inhibition of adenovirus-mediated p27kip1 gene on growth of esophageal carcinoma cell strain.

AIM: To investigate the inhibition of p27kip1 gene on the growth of esophageal carcinoma cell strain (EC9706). METHODS: Recombinant adenovirus Ad-p27kip1 was constructed and transfected into esophageal carcinoma cell EC-9706, and its effect on p27kip1 expression, the growth of esophageal carcinoma cell, DNA replication, protein synthesis, cell multiplication and apoptosis were explored by means of cell growth count, 3H-TdR, 3H-Leucine incorporation, flow cytometry, DNA fragment analysis and TUNEL. RESULTS: Recombinant adenovirus Ad-p27kip1 was successfully constructed with a virus titer of 1.24 X 10(12) pfu/ml. p27kip protein expression increased markedly after EC-9706 transfection, while incorporation quantity of 3H-TdR and 3H-Leucine decreased significantly. The growth of esophageal carcinoma cell was inhibited obviously. Testing of flow cytometry displayed a typical apoptosis peak, and DNA gel electrophoresis showed a typical apoptosis ladder. TUNEL showed the apoptosis rate of Ad-p27kip1 group and control group to be 37.3% and 1.26% (P<0.001) respectively. CONCLUSION: Ad-p27kip1 can inhibit the growth and multiplication of esophageal carcinoma cells and induce apoptosis. Therefore, enhanced p27kip1 expression may be a new way to treat esophageal carcinoma.