Nicotine induces cell survival and chemoresistance by stimulating Mcl-1 phosphorylation and its interaction with Bak in lung cancer

Nicotine is a major carcinogen in cigarettes, which can enhance cell proliferation and metastasis and increase the chemoresistance of cancer cells. Our previous data found that nicotine promotes cell survival in lung cancer by affecting the expression of antiapoptotic protein Mcl-1, suggesting that the Mcl-1 may be a therapeutic target for patients with lung cancer. In this study, we found that the effects of drug resistance on nicotine-induced lung cancer cell lines were shown to influence the phosphorylation of Mcl-1. Moreover, nicotine induces Mcl-1 phosphorylation exclusively at the T163 site, which results in enhancement of the antiapoptotic activity of Mcl-1 and increased cell survival. Meanwhile, nicotine can reduce the sensitivity of H1299 cells to CDDP via enhancement of the binding of Mcl-1 to Bak, which inhibits the proapoptotic effect of Bak and ultimately leads to increased survival and drug resistance of lung cancer cells. Thus, nicotine-induced cell survival and chemoresistance may occur in a mechanism by stimulating Mcl-1 phosphorylation and its interaction with Bak, which may contribute to improving the efficacy of chemotherapy in the treatment of human lung cancer.

Role of the novel gene BZW2 in the development of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in adults. Basic leucine zipper and W2 domains 2 (BZW2) is a member of the basic-region leucine zipper (bZIP) superfamily of transcription factors. Here, we found that BZW2 expression was substantially increased in both human HCC tissues and cell lines, which was correlated with the clinical progression of patients with HCC. Silence of BZW2 in HCC cells by infecting with the lentivirus for delivering BZW2 shRNA (short hairpin RNA), prohibits cell progression, as determined by the suppressed cell proliferation, clonality, invasion, and increased cell apoptosis. Furthermore, overexpression of BZW2 promotes drug resistance of HCC cells, as shown by the attenuated suppression of cell viability and invasion following rapamycin (RAPA) treatment. Mechanistically, overexpression (or silence) of BZW2 in HCC cells significantly stimulates (or decreases) the activation of the PI3K/AKT/mTOR signaling pathway, which is responsible for HCC progression. Thus, increased BZW2 expression in HCC can induce HCC progression and drug resistance via stimulating the PI3K/AKT/mTOR pathway, which may represent a new therapeutic target for HCC.

DNA methylation biomarkers in stool for early screening of colorectal cancer

Objective: Detection of aberrant methylated genes in feces has been developed as an early screening method for colorectal cancer. The aim of this study was to probe the methylation status of SEPT9, BMP3, NDRG4, and SDC2 in stool and study whether methylation of these genes is associated with colorectal cancer. Materials and Methods: DNAs were isolated and purified from cancerous and non-cancerous stool samples and colorectal cancer tissue. Gene methylation levels were quantified by methylation-specific PCR on SEPT9, BMP3, NDRG4, and SDC2 and analyzed by a diagnostic model. Results: DNA methylation of SEPT9, NDRG4 and SDC2, but not BMP3, had diagnostic potential for detecting colorectal cancer. Moreover, integration of SEPT9, NDRG4, and SDC2 methylation demonstrated high feasibility for detecting colorectal cancer and adenoma, with better performance on colorectal cancer than adenoma. Conclusion: The methylation of SEPT9, NDRG4, and SDC2 in stool may be a potential biomarker for early screening of colorectal cancer.

Phylogenetic classification of hemagglutinin gene of H9N2 avian influenza viruses isolated in China during 2012-2016 and evaluation of selected candidate vaccine strains

H9N2 subtype avian influenza virus (AIV) was the highly contagious pathogen which has caused severe losses in the poultry industry throughout China in recent years. Using current epidemic viruses as vaccine was an effective way to prevent infection of H9N2 subtype AIV. In this study, a total of 23 H9N2 subtype AIV strains were isolated in 200 samples from 13 provinces of China during 2012-2016. The sequencing and phylogenetic analysis of the hemagglutinin gene sequence of the isolation strains showed that 22 isolation strains were clustered to h9.4.2.5 lineage, while only 1 belonged to h9.4.2.6. The data of cross-HI, neutralization and cross-immune protection shown that the A/chicken/Hunan/HN/2015 (HN) and A/chicken/Shandong/SD/2014 (SD) strains as vaccine could effectively protect present viruses infection compared with other strains. These results indicated that current epidemic viruses were mainly belong to h9.4.2.5 lineage and HN and SD strains as candidate vaccine strains were potentiality for the protection of present H9N2 subtype AIV infection.

Niclosamide Inhibits Cell Growth and Enhances Drug Sensitivity of Hepatocellular Carcinoma Cells via STAT3 Signaling Pathway

Aims: Hepatocellular carcinoma (HCC) is the sixth most common malignant tumor worldwide, with a high mortality rate at advanced stages. In this study, we investigated the effect of niclosamide on cell growth and drug sensitivity in human HCC and elucidated the underlying mechanism.

Methods: Three human HCC cell lines (HepG2, QGY-7703 and SMMC-7721) were used to evaluate the effect of niclosamide. Cell proliferation was measured by MTT assay and colony formation assay. Assessment of apoptosis was evaluated by flow cytometry and Hoechst staining. The mRNA and protein levels were analyzed by real-time PCR and western blot, respectively.

Results: Niclosamide suppressed cell viability, inhibited clone formation, and induced cell apoptosis in HCC cells dose- and time-dependently. Furthermore, niclosamide synergized with cisplatin to promote the apoptosis of HCC cells. With niclosamide treatment, phospho-STAT3 (Y705) was inactivated and the downstream antiapoptotic proteins Mcl-1 and survivin were downregulated at both mRNA and protein levels in HCC cells.

Conclusion: Niclosamide has effective function in anti-HCC and may be a single or combined drug treatment for HCC and acts via the STAT3 signaling pathway.

Smooth muscle cell-specific Tgfbr1 deficiency attenuates neointimal hyperplasia but promotes an undesired vascular phenotype for injured arteries

Neointimal hyperplasia (NIH) and inward wall remodeling cause arterial restenosis and failure of bypass vein grafts. Previous studies from our group suggest that transforming growth factor (TGF) β promotes these pathologies via regulating cell kinetics at the early stage and matrix metabolism at the late stage. Although these temporal TGFβ effects may result from its signaling in different cell groups, the responsible cell type has not been identified. In the current study, we evaluated the effect of smooth muscle cell (SMC)‐specific TGFβ signaling through its type I receptor TGFBR1 on NIH and wall remodeling of the injured femoral arteries (FAs). An inducible Cre/loxP system was employed to delete SMC Tgfbr1 (Tgfbr1^iko). Mice not carrying the Cre allele (Tgfbr1^f/f) served as controls. The injured FAs were evaluated on d3, d7, and d28 postoperatively. Tgfbr1^iko attenuated NIH by 92%, but had insignificant influence on arterial caliber when compared with Tgfbr1^f/f controls on d28. This attenuation correlated with greater cellularity and reduced collagen content. Compared with Tgfbr1^f/fFAs, however, Tgfbr1^ikoFAs exhibited persistent neointimal cell proliferation and cell apoptosis, with both events at a greater rate on d28. Tgfbr1^ikoFAs additionally contained fewer SMCs and more inflammatory infiltrates in the neointima and displayed a thicker adventitia than did Tgfbr1^f/fFAs. More MMP9 proteins were detected in the adventitia of Tgfbr1^ikoFAs than in that of Tgfbr1^f/f controls. Our results suggest that disruption of SMC Tgfbr1 inhibits arterial NIH in the short term, but the overall vascular phenotype may not favor long‐term performance of the injured arteries.

An X-linked Myh11-CreERT2 mouse line resulting from Y to X chromosome-translocation of the Cre allele

The Myh11-CreER^T2 mouse line (Cre⁺ ) has gained increasing application because of its high lineage specificity relative to other Cre drivers targeting smooth muscle cells (SMCs). This Cre allele, however, was initially inserted into the Y chromosome (X/Y^Cre+ ), which excluded its application in female mice. Our group established a Cre⁺ colony from male ancestors. Surprisingly, genotype screening identified female carriers that stably transmitted the Cre allele to the following generations. Crossbreeding experiments revealed a pattern of X-linked inheritance for the transgene (k > 1000), indicating that these female carries acquired the Cre allele through a mechanism of Y to X chromosome translocation. Further characterization demonstrated that in hemizygous X/X^Cre+ mice Cre activity was restricted to a subset arterial SMCs, with Cre expression in arteries decreased by 50% compared to X/Y^Cre+ mice. This mosaicism, however, diminished in homozygous X^Cre+ /X^Cre+ mice. In a model of aortic aneurysm induced by a SMC-specific Tgfbr1 deletion, the homozygous X^Cre+ /X^Cre+ Cre driver unmasked the aortic phenotype that is otherwise subclinical when driven by the hemizygous X/X^Cre+ Cre line. In conclusion, the Cre allele carried by this female mouse line is located on the X chromosome and subjected to X-inactivation. The homozygous X^Cre+ /X^Cre+ mice produce uniform Cre activity in arterial SMCs.

Mcl-1 suppresses abasic site repair following bile acid-induced hepatic cellular DNA damage

In cholestasis, increases in bile acid levels result in the generation of reactive oxygen species and the induction of DNA damage and mutation. It is believed that bile acid accumulation is associated with liver tumorigenesis. However, the mechanism that underpins this phenomenon remains to be elucidated. Mcl-1, which is overexpressed in hepatic cells, is a pro-survival member of the Bcl-2 family. In this study, we observed that Mcl-1 potently suppresses the repair of bile acid-induced abasic (apurinic/apyrimidinic) sites in DNA lesions. Upon exposure of hepatic cells to glycochenodeoxycholate, one of the major conjugated human bile acids, we observed an increase in AP site accumulation along with induction of poly(ADP-ribose) polymerase and XRCC1 ( X-Ray Repair Cross Complementing 1). In addition, accumulation of Mcl-1 was observed in the nuclei of QGY-7703 cells in response to glycochenodeoxycholate stimulation. Knockdown of endogenous Mcl-1 by RNA interference significantly accelerated the repair of DNA lesions in glycochenodeoxycholate-treated cells. However, unlike XRCC1, poly(ADP-ribose) polymerase was induced following Mcl-1 knockdown. Conversely, poly(ADP-ribose) polymerase suppression was observed following glycochenodeoxycholate treatment of cells overexpressing Mcl-1. Moreover, AP-site counting analyses revealed that DNA repair activity was enhanced in cells overexpressing poly(ADP-ribose) polymerase under glycochenodeoxycholate stress conditions. It is well known that poly(ADP-ribose) polymerase plays a crucial role in the base excision repair pathway. Thus, our findings suggest that Mcl-1 suppresses base excision repair by inhibiting poly(ADP-ribose) polymerase induction following glycochenodeoxycholate-induced DNA damage. These results potentially explain how bile acid accumulation results in genetic instability and carcinogenesis.

Phosphorylation of Bcl-2 plays an important role in glycochenodeoxycholate-induced survival and chemoresistance in HCC

Hepatocellular carcinoma (HCC) is a highly malignant tumor and can evolve rapidly to resistance to chemotherapies. Glycochenodeoxycholate (GCDA), which is toxic and hydrophobic, is the main ingredient in the bile and associated with carcinogenesis of gastrointenstinal tumors. Bcl-2 is the most important anti-apoptotic protein and overexpressed in various human tumors. In the present study, we found that GCDA can induce the chemoresistance of human liver cancer cells and specific depletion of Bcl-2 by RNA interference blocks GCDA-stimulated chemoresistance, which indicate the pivotal role of Bcl-2 in such process. Mechanistically, GCDA simultaneously stimulates phosphorylation of Bcl-2 at Ser70 site and activates extracellular signal-regulated kinase 1/2 (ERK1/2), and inhibition of ERK1/2 by PD98059 (MAPK/ERK1/2 inhibitor) or siRNA (targeting ERK1/2) suppresses GCDA-stimulated phosphorylation of Bcl-2 and significantly attenuates the survival and chemoresistance induced by GCDA in liver cancer cells. Thus, GCDA-induced survival and chemoresistance of liver cancer cells may occur through activation of Bcl-2 by phosphorylation at Ser70 site through MAPK/ERK1/2 pathway, which may contribute to the development of human liver cancer and chemoresistance.

The prevalence of and risk factors for prostatitis-like symptoms and its relation to erectile dysfunction in Chinese men

The aim of this study was to describe the prevalence of and risk factors for prostatitis-like symptoms and its relation to erectile dysfunction (ED) among southern Chinese men. Data were collected from 2790 men attending the Fangchenggang Area Male Healthy and Examination Survey from September 2009 to December 2009. The prostatitis-like symptoms were assessed by the NIH Chronic Prostatitis Symptom Index and ED was assessed using the 5-item International Index of Erectile Function. Lifestyle and demographic characteristics were obtained through a questionnaire. Prevalence of prostatitis-like symptoms was 12.4% among 2790 Chinese men aged 20-84 years. In smokers who smoked ≥20 cigarettes per day (age-adjusted OR = 1.29; 95% CI = 1.00-1.66; p = 0.04), physical inactivity (age-adjusted OR = 1.31; 95% CI = 1.03-1.66; p = 0.02) was a significant risk factor for prostatitis-like symptoms. Alcohol consumption (daily drinking) also was a risk factor for prostatitis-like symptoms, although the differences were not statistically significant (age-adjusted OR = 1.36; 95% CI = 0.96-1.92; p = 0.07). Those with diabetes may also be at higher risk for prostatitis-like symptoms (age-adjusted OR = 1.37; 95% CI = 0.85-2.21; p = 0.19). In addition, men with ED were more likely to have had prostatitis-like symptoms (age-adjusted OR = 1.86; 95% CI = 0.47-2.36; p < 0.0001), and the ORs increased with increasing severity of ED status (mild ED, mild to moderate ED, and moderate to severe ED were 1.57, 2.62, and 3.24, respectively. Test for trend, p = 0.0001). Our results show that prostatitis-like symptoms are prevalent in Southern China affecting men of all ages. Smoking, drinking, lack of physical activity, and elevated plasma glucose level were associated with an increased risk of prostatitis-like symptoms. In addition, our results reveal that ED accounted for a large proportion (61.5%) among men with prostatitis-like symptoms; we also confirm the magnitude of ED associated with prostatitis-like symptoms. Thus, interventions to evaluate and improve ED might help ameliorate prostatitis-like symptoms and vice versa.

Abstract 309: A Female Myh11-CreER T2 Mouse Line Resulting from Y to X Chromosome-translation

The Myh11-CreER T2 mouse line ( Cre +/ ) provides a powerful tool for studying the role of smooth muscle cells (SMCs) in the pathogenesis of vascular diseases. The Cre allele was initially inserted into Y chromosome, and thus excluded its inheritance by female mice. However, a number of vascular diseases exhibit sexual dimorphism in development and progression, and the underlying mechanisms may involve regulation of SMC biology by the dosage-effects of sex-linked genes and gender. A Cre line that induces SMC-specific gene deletion in female mice would complement the existing Cre +/ line to address this critical issue. Our lab established the Cre +/ colony with one male ancestor and it spontaneously separated to two subcolonies during subsequent breeding. One subcolony produced only male Cre +/ progenies, but the other produced both male and female Cre +/ progenies, indicating chromosome-translocation of the Cre allele. In view of this observation, we mapped the chromosome-location of the Cre allele for these subcolonies with cross-breeding experiments. The 1 st experiment crossed two Cre +/ males from the first subcolony with four Cre -/ females. Of the produced progenies, all males ( n =9) carried and all females ( n =22) did not carry the Cre allele, which favors Y chromosome- ( Y Cre+ ) over autosome-location of the Cre allele in this subcolony (Bayes Factor>1000). In the 2 nd experiment, a Cre +/ female from the second subcolony was bred with a Cre -/ male. Then, a Cre +/ male progeny of these breeders was mated with a Cre -/ female. The former breeding pair exhibited equal inheritance of the Cre allele by its male and female offspring. The latter breeding pair showed that all female progenies ( n =8) did, but all male progenies ( n =4) did not, carry the Cre allele. The data favors X chromosome- ( X Cre+ ) over autosome-location of the Cre allele in this subcolony (Bayes Factor>1000). To assess the recombination driven by Cre +/ allele with different chromosome-location, we crossed X Cre+ and Y Cre+ strains with R26R reporter mice. Robust Cre activity (x-gal staining) was observed in vascular SMCs of Y Cre+ and X Cre+ mice. The X Cre+ mice generated via Y to X chromosome-translocation thus represents a novel strain that is suitable for inducible gene deletion in SMCs of female mice.

Abstract 369: SMC-Specific Tgfbr1 Deficiency Inhibits Neointimal Hyperplasia In Injured Arteries

Introduction: Stented arteries and vein bypass grafts fail due to neointimal hyperplasia (NIH). Transforming growth factor (TGF)-β has been identified as a driving force for this pathology. Our previous studies suggest that TGFβ contributes to NIH via regulating cell kinetics at early stage and matrix metabolism at late stage. While this differential TGFβ effect may result from its signaling in different cell-groups, the dominant cellular effectors at each stage remain to be determined. In this study, we evaluated the effect of TGFβ signaling in smooth muscle cell (SMCs) on NIH in injured arteries.

Methods and results: An inducible Cre/loxP system driven by a Myh11 promoter was employed to delete SMC-specific Tgfbr1 ( Tgfbr1 iko ). Male mice at 10 weeks of age were used in the study and those not carrying the Cre allele ( Tgfbr1 f/f ) served as controls. On the following day of the last tamoxifen injection (day 0, d0), animals received transmural mechanical injury to induce NIH in femoral arteries (FAs). By d28, Tgfbr1 iko attenuated NIH by 90% compared with Tgfbr1 f/f . However, the injured Tgfbr1 iko FAs contained fewer α-actin positive cells and displayed significantly higher rate of cell proliferation and apoptosis with less matrix deposition than Tgfbr1 f/f controls in neointima. Intense inflammatory infiltration was detected in adventitia of Tgfbr1 iko , but not Tgfbr1 f/f , FAs. To explore mechanisms underlying these cellular events, we examined the growth of SMCs explanted from Tgfbr1 iko and Tgfbr1 f/f aortas and assessed their response to TGFβ stimulation. As expected, TGFβ1 inhibited cell growth and induced expression of collagen and elastin in Tgfbr1 f/f SMCs. In contrast, Tgfbr1 iko SMCs were resistant to TGF-β1 stimulation, evidenced by insignificant change in levels of these variables. Intriguingly, Tgfbr1 iko SMCs grew significantly slower than Tgfbr1 f/f SMCs under standard culture condition. Daily refreshment of culture medium doubled the population-growth of Tgfbr1 iko , but not Tgfbr1 f/f , SMCs, indicating production of growth inhibitory factor(s) by Tgfbr1 iko SMCs.

Conclusion: Blockade of SMC-specific TGFBR1 activity inhibits NIH in a short-term, but, the resultant phenotype may not favor long-term performance of the injured arteries.

The International Association for the Study of Lung Cancer Lung Cancer Staging Project: Proposals for the Revision of the Clinical and Pathologic Staging of Small Cell Lung Cancer in the Forthcoming Eighth Edition of the TNM Classification for Lung Cancer

INTRODUCTION

Small cell lung cancer (SCLC) is commonly classified as either limited or extensive, but the Union for International Cancer Control TNM Classification of Malignant Tumours seventh edition (2009) recommended tumor, node, and metastasis (TNM) staging based on analysis of the International Association for the Study of Lung Cancer (IASLC) database.

METHODS

Survival analyses were performed for clinically and pathologically staged patients presenting with SCLC from 1999 through 2010. Prognosis was compared in relation to the TNM seventh edition staging to serve as validation and analyzed in relation to proposed changes to the T descriptors found in the eighth edition.

RESULTS

There were 5002 patients: 4848 patients with clinical and 582 with pathological stages. Among these, 428 had both. Survival differences were confirmed for T and N categories and maintained in relation to proposed revisions to T descriptors for seventh edition TNM categories and proposed changes in the eighth edition. There were also survival differences, notably at 12 months, in patients with brain-only single-site metastasis (SSM) compared to SSM at other sites, and SSM without a pleural effusion showed a better prognosis than other patients in the M1b category.

CONCLUSION

We confirm the prognostic value of clinical and pathological TNM staging in patients with SCLC, and recommend continued usage for SCLC in relation to proposed changes to T, N, and M descriptors for NSCLC in the eighth edition. However, for M descriptors, it remains uncertain whether survival differences in patients with SSM in the brain simply reflect better treatment options rather than better survival based on anatomic extent of disease.