The potential role of hydrogen sulfide in cancer cell apoptosis.

For a long time, hydrogen sulfide (H2S) has been considered a toxic compound, but recent studies have found that H2S is the third gaseous signaling molecule which plays a vital role in physiological and pathological conditions. Currently, a large number of studies have shown that H2S mediates apoptosis through multiple signaling pathways to participate in cancer occurrence and development, for example, PI3K/Akt/mTOR and MAPK signaling pathways. Therefore, the regulation of the production and metabolism of H2S to mediate the apoptotic process of cancer cells may improve the effectiveness of cancer treatment. In this review, the role and mechanism of H2S in cancer cell apoptosis in mammals are summarized.

Cystathionine γ-lyase mediates cell proliferation, migration, and invasion of nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is an epithelia-derived malignancy with a distinctive geographic distribution. Cystathionine γ-lyase (CSE) is involved in cancer development and progression. Nevertheless, the role of CSE in the growth of NPC is unknown. In this study, we found that CSE levels in human NPC cells were higher than those in normal nasopharyngeal cells. CSE overexpression enhanced the proliferative, migrative, and invasive abilities of NPC cells and CSE downregulation exerted reverse effects. Overexpression of CSE decreased the expressions of cytochrome C, cleaved caspase (cas)-3, cleaved cas-9, and cleaved poly-ADP-ribose polymerase, whereas CSE knockdown exhibited reverse effects. CSE overexpression decreased reactive oxygen species (ROS) levels and the expressions of phospho (p)-extracellular signal-regulated protein kinase 1/2, p-c-Jun N-terminal kinase, and p-p38, but promoted the expressions of p-phosphatidylinositol 3-kinase (PI3K), p-AKT, and p-mammalian target of rapamycin (mTOR), whereas CSE knockdown showed oppose effects. In addition, CSE overexpression promoted NPC xenograft tumor growth and CSE knockdown decreased tumor growth by modulating proliferation, angiogenesis, cell cycle, and apoptosis. Furthermore, DL-propargylglycine (an inhibitor of CSE) dose-dependently inhibited NPC cell growth via ROS-mediated mitogen-activated protein kinase (MAPK) and PI3K/AKT/mTOR pathways without significant toxicity. In conclusion, CSE could regulate the growth of NPC cells through ROS-mediated MAPK and PI3K/AKT/mTOR cascades. CSE might be a novel tumor marker for the diagnosis and prognosis of NPC. Novel donors/drugs that inhibit the expression/activity of CSE can be developed in the treatment of NPC.

Cystathionine ß-Synthase Regulates the Proliferation, Migration, and Invasion of Thyroid Carcinoma Cells.

Thyroid cancer is considered to be one of the most common endocrine tumors worldwide. Cystathionine ß-synthase (CBS) plays a crucial role in the occurrence of several types of malignancies. And yet, the mechanism of action of CBS in the growth of thyroid carcinoma cells is still unrevealed. We found that CBS level in thyroid carcinoma tissue was higher than that in adjacent normal tissue. The overexpression of CBS enhanced the proliferation, migration, and invasion of thyroid cancer cells, while the downregulation of CBS exerted reverse effects. CBS overexpression reduced the levels of cleaved caspase-3 and cleaved poly ADP-ribose polymerase in thyroid cancer cells, whereas CBS knockdown showed reverse trends. CBS overexpression decreased reactive oxygen species (ROS) levels but increased the levels of Wnt3a and phosphorylations of phosphatidylinositol 3-kinase (PI3K), protein kinase B (PKB/AKT), mammalian target of rapamycin (mTOR), ß-catenin, and glycogen synthase kinase-3 beta, while CBS knockdown exerted opposite effects. In addition, CBS overexpression promoted the growth of xenografted thyroid carcinoma, whereas CBS knockdown decreased the tumor growth by modulating angiogenesis, cell cycle, and apoptosis. Furthermore, aminooxyacetic acid (an inhibitor of CBS) dose-dependently inhibited thyroid carcinoma cell growth. CBS can regulate the proliferation, migration, and invasion of human thyroid cancer cells via ROS-mediated PI3K/AKT/mTOR and Wnt/ß-catenin pathways. CBS can be a potential biomarker for diagnosing or prognosing thyroid carcinoma. Novel donors that inhibit the expression of CBS can be developed in the treatment of thyroid carcinoma.

Impact of the factors shaping gut microbiota on obesity.

Obesity is considered as a risk factor for chronic health diseases such as heart diseases, cancer and diabetes 2. Reduced physical activities, lifestyle, poor nutritional diet and genetics are among the risk factors associated with the development of obesity. In recent years, several studies have explored the link between the gut microbiome and the progression of diseases including obesity, with the shift in microbiome abundance and composition being the main focus. The alteration of gut microbiome composition affects both nutrients metabolism and specific gene expressions, thereby disturbing body physiology. Specifically, the abundance of fibre-metabolizing microbes is associated with weight loss and that of protein and fat-metabolizing bacteria with weight gain. Various internal and external factors such as genetics, maternal obesity, mode of delivery, breastfeeding, nutrition, antibiotic use and the chemical compounds present in the environment are known to interfere with the richness of the gut microbiota (GM), thus influencing weight gain/loss and ultimately the development of obesity. However, the effectiveness of each factor in potentiating the shift in microbes' abundance to result in significant changes that can lead to obesity is not yet clear. In this review, we will highlight the factors involved in shaping GM, their influence on obesity and possible interventions. Understanding the influence of these factors on the diversity of the GM and how to improve their effectiveness on disease conditions could be keys in the treatment of metabolic diseases.

Role of hydrogen sulfide donors in cancer development and progression.

In recent years, a vast number of potential cancer therapeutic targets have emerged. However, developing efficient and effective drugs for the targets is of major concern. Hydrogen sulfide (H2S), one of the three known gasotransmitters, is involved in the regulation of various cellular activities such as autophagy, apoptosis, migration, and proliferation. Low production of H2S has been identified in numerous cancer types. Treating cancer cells with H2S donors is the common experimental technique used to improve H2S levels; however, the outcome depends on the concentration/dose, time, cell type, and sometimes the drug used. Both natural and synthesized donors are available for this purpose, although their effects vary independently ranging from strong cancer suppressors to promoters. Nonetheless, numerous signaling pathways have been reported to be altered following the treatments with H2S donors which suggest their potential in cancer treatment. This review will analyze the potential of H2S donors in cancer therapy by summarizing key cellular processes and mechanisms involved.

Gene Expression Profiling Reveals Distinct Molecular Subtypes of Esophageal Squamous Cell Carcinoma in Asian Populations.

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide, particularly in Asian populations, and responds poorly to conventional therapy. Subclassification of ESCCs by molecular analysis is a powerful strategy in extending conventional clinicopathologic classification, improving prognosis and therapy. Here we identified two ESCC molecular subtypes in Chinese population using gene expression profiling data and further validated the molecular subtypes in two other independent Asian populations (Japanese and Vietnamese). Subtype I ESCCs were enriched in pathways including immune response, while genes overexpressed in subtype II ESCCs were mainly involved in ectoderm development, glycolysis process, and cell proliferation. Specifically, we identified potential ESCC subtype-specific diagnostic markers (FOXA1 and EYA2 for subtype I, LAMC2 and KRT14 for subtype II) and further validated them in a fourth Asian cohort. In addition, we propose a few subtype-specific therapeutic targets for ESCC, which may guide future ESCC clinical treatment when further validated.

A Novel Cx50 Insert Mutation from a Chinese Congenital Cataract Family Impairs Its Cellular Membrane Localization and Function.

Mutations in GJA8 are associated with hereditary autosomal dominant and recessive cataract formation. In this study, a novel insert mutation in GJA8 was identified in a Chinese congenital cataract family and cosegregated with the disease in this pedigree. This insert mutation introduces five additional amino acid residues YAVHY after histidine at the 95 site (p.H95_A96insYAVHY) within the second transmembrane (TM2) domain of Cx50 protein (Cx50-insert). Ectopic expression of Cx50-insert protein impairs the hemichannel functions and gap junction activity compared to wild-type Cx50 protein in human lens epithelial cells. Cx50-insert proteins were mislocated from cytoplasmic membrane to endoplasmic reticulum and lysosome. In mouse lens tissue, our results showed that Cx50 predominant expresses in epithelial cells and fiber cells at the transition zone of lens hinting its roles in lens differentiation. Taken together, these data suggest that the novel insert mutation in the TM2 domain of Cx50 protein, which impairs its trafficking to the cell membrane and gap-junction function, is associated with the cataract formation in this Chinese pedigree.

Defective heat shock factor 1 inhibits the growth of fibrosarcoma derived from simian virus 40/T antigen­transformed MEF cells.

Heat shock factor 1 (Hsf1) serves an important role in regulating the proliferation of human tumor cell lines in vitro and tissue specific tumorigenesis in certain mouse models. However, its role in viral­oncogenesis remains to be fully elucidated. In the current study, the role of Hsf1 in fibroblastoma derived from simian virus 40/T antigen (SV40/TAG)­transformed mouse embryonic fibroblast (MEF) cell lines was investigated. Knockout of Hsf1 inhibited MEF cell proliferation in vitro and fibroblastoma growth and metastasis to the lungs in vivo in nude mice. Knockout of Hsf1 increased the protein expression levels of p53 and phosphorylated retinoblastoma protein (pRb), however reduced the expression of heat shock protein 25 (Hsp25) in addition to the expression of the angiogenesis markers vascular endothelial growth factor, cluster of differentiation 34 and factor VIII related antigen. Furthermore, immunoprecipitation indicated that knockout of Hsf1 inhibited the association between SV40/TAG and p53 or pRb. These data suggest that Hsf1 is involved in the regulation of SV40/TAG­derived fibroblastoma growth and metastasis by modulating the association between SV40/TAG and tumor suppressor p53 and pRb. The current study provides further evidence that Hsf1 may be a novel therapeutic target in the treatment of cancer.

Function of Hsf1 in SV40 T­antigen­transformed HEK293T cells.

Heat shock factor 1 (HSF1), a main regulator of the heat shock response in eukaryotes, increases cell survival in numerous pathophysiological conditions. The aim of the present study was to o bserve the function of defective HSF1 expression in HEK293T cells. shRNA of human HSF1 was constructed into the retroviral vector pLTHR generating pLTHR­shRNA­HSF1. The shRNA was transiently transfected into HEK293T cells to silence the expression of the HSF1 gene. Cell colony formation, MTT and cell cycle assays were used to analyze the SV40 T­antigen (Ag)­transformed cell proliferation rate. Immunoblotting was used to study the protein expression of HSF1, SV40 T­Ag, p53, p21, heat shock protein 90 (Hsp90), Hsp70 and Hsp25. The results revealed that a deficiency in HSF1 expression inhibited cellular growth. Defective HSF1 upregulated the protein expression of p53, retinoblastoma protein (Rb) and SV40 T­Ag, and reduced the association between SV40 T­Ag and p53/Rb, which resulted in growth inhibition of SV40 T­Ag­transformed cells. In conclusion, HSF1 is involved in the regulation of SV40 T­Ag­induced cell growth and modulates the expression of p53 and Rb proteins.

The transcription activity of heat shock factor 4b is regulated by FGF2.

Heat shock factor 4b has been found to be closely associated with postnatal lens development. It expresses in postnatal lens epithelial and secondary fiber cells and controls the expression of small heat shock proteins which are important for lens homeostasis. However, the signal pathways underlying Hsf4b are still not completely understood. Here we present that Hsf4b transcription activity is regulated by FGF2 a key growth factor that is involved in regulating lens development at multiple stages. FGF2 can promote Hsf4b nuclear-translocation and the expression of Hsp25 and αB-crystallin, the key downstream targets of Hsf4b in the Hsf4b-reconstituted mouse hsf4-/- lens epithelial cells. Further study indicates that FGF2 can induce Hsf4b protein stabilization through ERK1/2-mediated posttranslational phosphorylation or sumoylation. Hsf4b can promote FGF2-induced morphology transition from lens epithelial cell to the fiber cell, and this morphology transition can be inhibited by ERK1/2 inhibitor U0126. Taken together, our data demonstrate that Hsf4b is a novel downstream transcription factor of FGF2, and its transcription activity is associated with FGF2-modulated lens epithelial cell-fiber cell transition.

Gene delivery to tumor cells by cationic polymeric nanovectors coupled to folic acid and the cell-penetrating peptide octaarginine.

Target ligand folic acid (FA) and cell-penetrating peptide octaarginine (R8) were coupled with the gene vectors (PEI(600)-CyD, PC) composed of ß-cyclodextrin (ß-CyD) and low-molecular-weight polyethylenimine (PEI, Mw 600) to form nanovectors for highly efficient gene delivery to tumor cells. The resultant ternary nanocomplexes of FA-PC/R8-PC/pDNA produced excellent gene transfaction abilities in the folate receptor (FR)-positive tumor cells in vitro and in vivo. The FR-mediated endocytosis and the R8-mediated transmembrane functionality together contributed to the high transfection levels. This study provides a promising means to produce gene nanovectors for in vivo applications.

(Coixan polysaccharide)-graft-polyethylenimine folate for tumor-targeted gene delivery.

CP-PEI-FA was prepared as an effective vector for in vitro and in vivo tumor-targeted gene delivery. The structures of the polymers were characterized, and their DNA condensation capability, particle sizes, zeta potentials, cytotoxicity and in vitro/in vivo transfection were examined. The cytotoxicity of CP-PEI-FA was significantly lower than that of PEI 25 kDa and close to that of PEI 1200. The in vitro transfection of CP-PEI-FA was tested in C6 and HeLa cells (FR-positive cells) and A549 cells (FR-negative cells). CP-PEI-FA showed a high targeting specificity and good gene transfection efficiency in FR-positive cells. These results indicate that CP-PEI-FA is a safe and effective polyplex-forming agent for both in vitro and in vivo transfection of plasmid DNA.

[Peptide MC10 mediated PEI-beta-CyD as a gene delivery vector targeting to Her-2 receptor].

OBJECTIVE: To develop a novel non-viral gene delivery vector based on polyethylenimine and beta-cyclodextrin targeting to Her-2 receptor (MC10-PEI-beta-CyD). METHODS: The PEI-beta-CyD was synthesized by low molecular weight polyethylenimine (PEI, Mw 600) cross-linked beta-cyclodextrin (beta-CyD) via N, N-carbonyldiimidazole (CDI). The chemical linker[N-succinimidy-3-(2-pyridyldithio) propionate, SPDP] was used to bind peptide MC10 (MARAKEGGGC) to PEI-beta-CyD to form the vector MC10-PEI-beta-CyD. The (1)H-NMR was used to confirm the structure of vector. The DNA condensing ability,and the particle size of MC10-PEI-beta-CyD/DNA complexes were demonstrated by gel retardation assay and electron microscope observation (TEM). Cell viability was tested by MTT assay. The transfection efficiency was determined on cultured SKOV-3, A549 and MCF-7 cells. RESULT: MC10 was linked onto PEI-beta-CyD successfully. The vector was able to condense DNA at N/P ratio of 5 and particle size was about (170 +/-35)nm. The vector showed low cytotoxicity and high transfection efficiency in cultured SKOV-3, A549 and MCF-7 cells. CONCLUSION: A novel non-viral vector MC10-PEI-beta-CyD with low cytotoxicity and high transfection efficiency has been successfully synthesized.

[Poly-aspartamide-glutamic acid grafted low molecular weight polyethylenimine as a novel non-viral gene vector].

OBJECTIVE: To develop a novel gene delivery vector with poly-aspartamide-glutamic acid and polyethylenimine as the backbone. METHODS: alpha, beta-poly-(N-2-hydroxypropyl)-D, L-aspartamide-glutamic acid (PHPAG) was synthesized and low molecular weight polyethylenimine (PEI 1.8 kDa) was grafted to form PHPAG-PEI 1800. Chemical and biological characterization of the polymer was identified. RESULT: The polymer was confirmed by (1)H-NMR, and the molecular weight was about 1.2 x 10(4). The ability of DNA binding was showed by gel retardation assay at N/P ratio of 3. 5. MTT assay showed that the polymer was non toxic in COS-7 and A293 cell lines. In vitro test demonstrated that it had high transfection efficiency in B16 and Hela cell lines. CONCLUSION: PHPAG-PEI 1800 was successfully synthesized,which might be a potential vector for gene delivery.

[Preparation of floxuridine loaded polycation and its antitumor activity].

OBJECTIVE: To develop a new prodrug of 5-fluorouracil-polyethylenimine-beta-cyclodextrin-floxuridine (PEI-beta-CyD-Fd) and to test its antitumor activity. METHODS: Floxuridine was conjugated to polyethylenimine-beta-cyclodextrin to form prodrug PEI-beta-CyD-Fd. The structure of synthesized PEI-beta-CyD-Fd was confirmed by (1)H-NMR, FT-IR and UV. MTT assay and cell wound healing assay were performed on human hepatic carcinoma cell line HepG2. RESULT: The drug loading was 2 %. The MTT assay and cell wound healing assay indicated that PEI-beta-CyD-Fd significantly inhibited proliferation and migration of HepG2 cells. CONCLUSION: The synthesized prodrug PEI-CyD-Fd has a significant antitumor activity on HepG2 cells.