Mingxin Zhang

Correlation of Nrf2, HO-1, and MRP3 in gallbladder cancer and their relationships to clinicopathologic features and survival.

BACKGROUND Gallbladder cancer (GC) is considered a relatively rare malignancy with extensively poor prognosis. To guide clinicians in selecting treatment options for GC patients, reliable markers predictive of poor clinical outcome are desirable. This study analyzed the correlation of NF-E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and multidrug resistance-related protein 3 (MRP3) in GC and their relationships to clinicopathologic features and survival. MATERIAL AND METHODS We immunohistochemically investigated 59 specimens of gallbladder adenocarcinoma tissues using Nrf2, HO-1, and MRP3 antibodies. RESULTS There were significant correlations between the high level of Nrf2, HO-1, and MRP3 expression and the tumor differentiation, Nevin staging, and metastasis. Significant positive correlations were found between the expression status of Nrf2 and that of HO-1 and MRP3 (r = 0.38, P = 0.008 and r = 0.59, P < 0.001, respectively). High Nrf2 expression was significantly associated with shorter overall survival times in univariate analysis (log-rank test, P < 0.001), being also identified as an independent prognostic factor in multivariate analysis (P = 0.035). CONCLUSIONS Nrf2, HO-1, and MRP3 were associated with certain clinicopathologic parameters in GC. Evaluation of Nrf2 expression may be an important factor in identifying a poor prognostic group of GC.

miR‐518b is down‐regulated, and involved in cell proliferation and invasion by targeting Rap1b in esophageal squamous cell carcinoma

MicroRNAs (miRNAs) represent a class of small non‐coding RNAs that regulate gene expression at the post‐transcriptional levels. Recent studies show that miRNAs may function as oncogenes or tumor suppressor genes. In this study, we demonstrated that miR‐518b was down‐regulated in esophageal squamous cell carcinoma (ESCC) tissues and correlated with metastasis and survival. miR‐518b suppressed the proliferation by inducing apoptosis and repressed the invasion in ESCC cells, but had no effect on the cell cycle. Furthermore, Rap1b was revealed to be directly regulated by miR‐518b. These findings indicate that miR‐518b may function as a tumor suppressor by targeting Rap1b in the development of ESCC and has important clinical and prognostic value.

Atrial natriuretic peptide modulates the proliferation of human gastric cancer cells via KCNQ1 expression.

Atrial natriuretic peptide (ANP) and brain NP (BNP) belong to the NP family that regulates mammalian blood volume and blood pressure. ANP signaling through NP receptor A (NPR-A)/cyclic guanosine 3′5′-monophosphate (cGMP)/ cGMP-dependent protein kinase (PKG) activates various downstream effectors involved in cell growth, apoptosis, proliferation and inflammation. Evidence has shown the critical role of plasma K+ channels in the regulation of tumor cell proliferation. However, the role of ANP in the proliferation of gastric cancer cells is not clear. In the present study, the expression of NPR-A in the human gastric cancer cell line, AGS, and the effect of ANP on the proliferation of AGS cells were investigated using western blotting, immunofluorescence, qPCR and patch clamp assays. The K+ current was also analyzed in the effect of ANP on the proliferation of AGS cells. NPR-A was expressed in the human gastric cancer AGS cell line. Lower concentrations of ANP promoted the proliferation of the AGS cells, although higher concentrations decreased their proliferation. Significant increases in the levels of cGMP activity were observed in the AGS cells treated with 10−10, 10−9 and 10−8 M ANP compared with the controls, but no significant differences were observed in the 10−7 and 10−6 M ANP groups. The patch clamp results showed that 10−9 M ANP significantly increased the tetraethylammonium (TEA)- and 293B-sensitive K+ current, while 10−6 M ANP significantly decreased the TEA- and 293B-sensitive K+ current. The results showed that 10−10 and 10−9 M ANP significantly upregulated the expression of potassium voltage-gated channel, KQT-like subfamily, member 1 (KCNQ1) at the protein and mRNA levels, although 10−7 and 10−6 M ANP significantly downregulated the expression of KCNQ1. The data indicated that lower and higher concentrations of ANP have opposite effects on the proliferation of AGS cells through cGMP-dependent or -independent pathways. KCNQ1 upregulation and downregulation by lower and higher concentrations of ANP, respectively, have separate effects on the promotion and inhibition of proliferation.

Mechanisms of Apoptin-induced cell death

Apoptin, a 13.6-kD protein encoded by chicken anemia virus, is paid more and more attention, since it selectively induces apoptosis in tumor cells while abolishes cytotoxic effect in normal cells. In addition, Apoptin shows different localization in tumor cells and normal cells: it predominantly accumulates in nucleus of tumor cells, whereas in normal cells, it is detected mainly in cytoplasm. There are various mechanisms implicated in the program of Apoptin-mediated cell death. Up to now, the interpretations have been recognized including that the particular domains control nucleocytoplasmic shuttling of Apoptin, phosphorylation on specific residue and varies relevant signaling contribute to Apoptin’s activity, and the partners interacted with Apoptin regulate activity or subcellular localization of Apoptin. In this review, we make a comprehensive survey of the existing evidence about mechanisms of Apoptin’s action, which might provide scientific basis to make progress in novel targeted tumor therapy.

Tumor-targeted delivery of TAT-Apoptin fusion gene using Escherichia coli Nissle 1917 to colorectal cancer

In view of the high incidence and mortality of the colorectal cancer, the limited efficacy and serious adverse effect of the conventional treatment, a novel alternative treatment needs to be developed. Recent studies have demonstrated that the targeted therapy as an alternative treatment showed a promising prospect. We hypothesized that construct a recombination non-pathogenic Escherichia coli Nissle 1917 (EcN), inserting a fusion gene TAT-Apoptin into this probiotic vector, as a targeted therapy strategy for patients of colorectal cancer. Compared with conventional treatments for tumors, the recombination EcN containing TAT-Apoptin fusion gene is capable of tumor-specific colonization, secretary expression and efficient intracellular delivery and therefore able to reduce the incidence of side effect and promote the efficiency of treatment.

Prostacyclin administration as a beneficial supplement to the conventional cancer chemotherapy.

Prostacyclin (PGI(2)) and its analogues protect from cardiovascular disease through pleiotropic effects such as vasodilation, inhibition of platelet aggregation, leukocyte adhesion, and vascular smooth muscle cell (VSMC) proliferation. Additionally, prostacyclin synthase (PGIS) and PGI(2) also possess anti-cancer properties. As of late (2009-2010), numerous studies have identified the deleterious side-effects of chemotherapy on the cardiovascular system, which have been deemed as a serious clinical issue. Cardiomyocyte damage, induced by oxidative stress, is one of the clinical consequences caused by routine cancer chemotherapy. Previous studies indicate iloprost, a PGI(2) analogue, can protect against doxorubicin-induced (DOX) cardiomyocyte injury in vitro and in vivo without compromising tumor suppression. Therefore, we hypothesize PGI(2) can be used as a cardioprotective supplement to attenuate the damaging cardiac effects caused by the traditional cancer chemotherapy regimen.