Apoptotic pathways in tumor progression and therapy

The Persistent Power of the Taxane/Platin Chemotherapy

The cancer chemotherapy regimen of a taxane and platinum combination was developed more than forty years ago, yet remains the cornerstone of treatment for several major cancer types today. Although many new agents targeting cancer genes and pathways have been developed and evaluated, none have been sufficient to replace the long-established taxane/platinum combination. This leads us to ponder why, after four decades of colossal efforts, multiple discoveries, and tremendous advances in understanding gene mutations and biology, the development of conceptually superior targeted therapies has not yet achieved overwhelming success in replacing cytotoxic chemotherapy. The concept of targeted therapy is based on the idea that blocking the altered pathway(s) crucial for cancer development (and maintenance), the disturbance in cellular signaling, metabolism, and functions will make the targeted cancer cells unfit and trigger programmed cell death in cancer cells, but without the significant side effects that limit chemotherapy. We propose that the lack of anticipated triumphs of targeted therapy stems from the desensitization of programmed cell death pathways during neoplastic transformation and malignant progression of cancer cells. This renders the targeting drugs largely ineffective at killing cancer cells and mostly insufficient in clinical implements. Recent advances in understanding suggest that, in contrast to targeted therapies, taxanes and platinum agents kill cancer cells by physical rupturing nuclear membranes rather than triggering apoptosis, making their effect independent of the intrinsic cellular programmed cell death mechanism. This new recognition of the non-programmed cell death mechanism in the success of chemotherapeutic agents, such as taxanes and platinum, may inspire oncologists and cancer researchers to focus their efforts more productively on developing effective non-programmed cell death cancer therapies to replace or significantly improve the application of the current standard taxane/platinum regimens.

Apoptosis Regulation in Dental Pulp Cells and PD-1/PD-L1 Expression Dynamics Under Ozone Exposure - A Pilot Approach

This study aimed to determine the effect of ozone on the expression of Bax and Bcl-2 genes in dental pulp cells. Additionally, the programmed cell death protein 1, programmed death-ligand 1, and CD200 antigens were determined in lymphocytes to assess their surface expression. Dental pulp cells were cultured from extracted healthy third molars and characterized as dental pulp stromal cells. Gene expression of Bcl-2 and Bax was analyzed at 0 s, 6 s, and 12 s of ozone exposure using real-time PCR. Lymphocytes from dental pulp were subjected to ozone exposure for 12 s and PD-1, PD-L1, and CD200/CD200R expression was analyzed by flow cytometry. Upon exposure to ozone for 6 s, the Bcl-2 expression decreased significantly to -0.09, and at 12 s, it increased significantly to 0.3. Bax gene expression level increased significantly to 0.188 after 6 s exposure, and at 12 s, to 0.16. Lymphocytes exposed to ozone for 12 s showed minimal changes in PD-1, PD-L1, and CD200/CD200R expression levels, indicating that oxidative stress does not impact the signaling pathways regulating these molecules. The significant upregulation of Bcl-2 at 12 s highlights the cells' effort to protect themselves from prolonged oxidative stress, possibly tipping the balance toward cell survival and tissue repair. However, the absence of changes in PD-1 and PD-L1 expression on lymphocytes under oxidative stress suggests that these molecules are not sensitive to oxidative stress in this context.

Pan-cancer analysis of the prognostic and immunological role of GJB2: a potential target for survival and immunotherapy

Background

GJB2 plays an essential role in the growth and progression of several cancers. However, asystematic pan-cancer analysis of GJB2 is lacking. Therefore, in this study, we performed a comprehensive pan-cancer analysis to determine the potential role of GJB2 in prognostic prediction and cancer immunotherapy response.

Methods

The differential expression of GJB2 in the tumor and adjacent normal tissues of various cancer types was analyzed using the TIMER, GEPIA, and Sangerbox databases. GEPIA and Kaplan-Meier plotter databases were used to analyze the survival outcomes based on GJB2 expression levels in pan-cancer. Furthermore, the association of GJB2 expression with the immune checkpoint (ICP) genes, tumor mutational load (TMB), microsatellite instability (MSI), neoantigens, and tumor infiltration of immune cells was analyzed using via the Sangerbox database. The cBioPortal database was used to determine the characteristics of GJB2 gene alterations in the cancer tissues. The STRING database was used to identify the GJB2-binding proteins. GEPIA database was used to identify the GJB2 co-expressed genes. DAVID was used to perform the functional enrichment analysis of gene ontology (GO) terms and KEGG pathways associated with GJB2. Finally, the mechanistic role of GJB2 in pancreatic adenocarcinoma (PAAD) was analyzed using the LinkedOmics database.

Results

The GJB2 gene was highly expressed in a variety of tumors. Furthermore, GJB2 expression levels showed significant positive or negative association with the survival outcomes in various cancers. GJB2 expression levels cor related with tumor mutational burden, microsatellite instability, neoantigens, and tumor infiltration of immune cells in multiple cancers. This suggested that GJB2 played a critical role in the tumor microenvironment. Functional enrichment analysis showed that the biological role of GJB2 in tumors included modulation of gap junction-mediated intercellular transport, regulation of cell communication by electrical coupling, ion transmembrane transport, autocrine signaling, apoptotic signaling pathway, NOD-like receptor signaling pathway, p53 signaling pathway, and PI3K-Akt signaling pathway.

Conclusions

Our study demonstrated that GJB2 played a significant role in tumorigenesis and tumor immunity in multiple cancers. Furthermore, GJB2 is a potential prognostic biomarker and a promising therapeutic target in multiple types of cancers.

RTA404, an Activator of Nrf2, Activates the Checkpoint Kinases and Induces Apoptosis through Intrinsic Apoptotic Pathway in Malignant Glioma

Background: Malignant glioma (MG) is an aggressive malignant brain tumor. Despite advances in multidisciplinary treatment, overall survival rates remain low. A trifluoroethyl amide derivative of 2-cyano-3-,12-dioxoolean-1,9-dien-28-oic acid (CDDO), CDDO-trifluoroethyl amide (CDDO-TFEA) is a nuclear erythroid 2-related factor 2/antioxidant response element pathway activator. RTA404 is used to inhibit proliferation and induce apoptosis in cancer cells. However, its effect on tumorigenesis in glioma is unclear. Methods: This in vitro study evaluated the effects of RTA404 on MG cells. We treated U87MG cell lines with RTA404 and performed assessments of apoptosis and cell cycle distributions. DNA content and apoptosis induction were subjected to flow cytometry analysis. The mitotic index was assessed based on MPM-2 expression. Protein expression was analyzed through Western blotting. Results: RTA404 significantly inhibited the cell viability and induced cell apoptosis on the U87MG cell line. The Annexin-FITC/PI assay revealed significant changes in the percentage of apoptotic cells. Treatment with RTA404 led to a significant reduction in the U87MG cells' mitochondrial membrane potential. A significant rise in the percentage of caspase-3 activity was detected in the treated cells. In addition, these results suggest that cells pass the G2 checkpoint without cell cycle arrest by RTA404 treatment in the MPM-2 staining. An analysis of CHK1, CHK2, and p-CHK2 expression suggested that the DNA damage checkpoint system seems also to be activated by RTA404 treatment in established U87MG cells. Therefore, RTA404 may not only activate the DNA damage checkpoint system, it may also exert apoptosis in established U87MG cells. Conclusions: RTA404 inhibits the cell viability of gliomas and induces cancer cell apoptosis through intrinsic apoptotic pathway in Malignant glioma. In addition, the DNA damage checkpoint system seems also to be activated by RTA404. Taken together, RTA404 activated the DNA damage checkpoint system and induced apoptosis through intrinsic apoptotic pathways in established U87MG cells.

ROS-Mediated Apoptosis and Autophagy in Ovarian Cancer Cells Treated with Peanut-Shaped Gold Nanoparticles

Background

Even with considerable improvement in treatment of epithelial ovarian cancer achieved in recent years, an increasing chemotherapy resistance and disease 5-year relapse is recorded for a majority part of patients that encourages the search for better therapeutic options. Gold nanoparticles (Au NPs) due to plethora of unique physiochemical features are thoroughly tested as drug delivery, radiosensitizers, as well as photothermal and photodynamic therapy agents. Importantly, due to highly controlled synthesis, it is possible to obtain nanomaterials with directed size and shape.

Methods

In this work, we developed novel elongated-type gold nanoparticles in the shape of nanopeanuts (AuP NPs) and investigated their cytotoxic potential against ovarian cancer cells SKOV-3 using colorimetric and fluorimetric methods, Western blot, flow cytometry, and fluorescence microscopy.

Results

Peanut-shaped gold nanoparticles showed high anti-cancer activity in vitro against SKOV-3 cells at doses of 1–5 ng/mL upon 72 hours treatment. We demonstrate that AuP NPs decrease the viability and proliferation capability of ovarian cancer cells by triggering cell apoptosis and autophagy, as evidenced by flow cytometry and Western blot analyses. The overproduction of reactive oxygen species (ROS) was noted to be a critical mediator of AuP NPs-mediated cell death.

Conclusion

These data indicate that gold nanopeanuts might be developed as nanotherapeutics against ovarian cancer.

Flavokawain C exhibits anti-tumor effects on in vivo HCT 116 xenograft and identification of its apoptosis-linked serum biomarkers via proteomic analysis

Chalcones and their derivatives belong to the flavonoid family. They have been extensively studied for their anticancer properties and some have been approved for clinical use. In this study, the in vivo anti-tumor activity of flavokawain C (FKC), a naturally occurring chalcone found in Kava (Piper methysticum Forst) was evaluated in HCT 116 cells (colon carcinoma). We also attempted to identify potential biomarkers and/or molecular targets in serum with applicability in predicting treatment outcome. The anti-tumor effects and toxicity of FKC were assessed using the xenograft nude mice model. Cisplatin was used as positive control. The anti-proliferative and apoptotic activities were then evaluated in tumor tissues treated with FKC. Furthermore, two-dimensional electrophoresis (2-DE) followed by protein identification using MALDI-TOF/TOF-MS/MS was performed to compare the serum proteome profiles between healthy nude mice and nude mice bearing HCT 116 tumor treated with vehicle solution and FKC, respectively. Our results showed that FKC treatment significantly inhibited HCT 116 tumor growth. In vivo toxicity studies showed that administration of FKC did not cause damage to major organs and had no significant effect on body weight. FKC was found to induce apoptosis in tumor, and this was associated with increased expression of cleaved caspase-3 and decreased expression of Ki67 in tumor tissues. Our proteomic analysis identified five proteins that changed in abundance - Ig mu chain C region (secreted form), GRP78, hemopexin, kininogen-1 and apolipoprotein E. Overall, our findings demonstrated the potential of FKC as an anti-cancer agent for the treatment of colon carcinoma.

The role of microRNAs in cell death pathways

MicroRNAs (miRNAs) are a class of noncoding RNAs that negatively regulate target messenger RNAs. In multicellular eukaryotes, numerous miRNAs perform basic cellular functions, including cell proliferation, differentiation, and death. Abnormal expression of miRNAs weakens or modifies various apoptosis pathways, leading to the development of human cancer. Cell death occurs in an active manner that maintains tissue homeostasis and eliminates potentially harmful cells through regulated cell death processes, including apoptosis, autophagic cell death, and necroptosis. In this review, we discuss the involvement of miRNAs in regulating cell death pathways in cancers and the potential therapeutic functions of miRNAs in cancer treatment.

Adenosine Signaling in the Tumor Microenvironment

Adenosine, deriving from ATP released by dying cancer cells and then degradated in the tumor environment by CD39/CD73 enzyme axis, is linked to the generation of an immunosuppressed niche favoring the onset of neoplasia. Signals delivered by extracellular adenosine are detected and transduced by G-protein-coupled cell surface receptors, classified into four subtypes: A₁, A_2A, A_2B, and A₃. A critical role of this nucleoside is emerging in the modulation of several immune and nonimmune cells defining the tumor microenvironment, providing novel insights about the development of novel therapeutic strategies aimed at undermining the immune-privileged sites where cancer cells grow and proliferate.

The role of apatinib combined with paclitaxel (aluminum binding type) in platinum-resistant ovarian cancer

OBJECTIVE

To assess the anti-tumor activity and side effects of different dosages of paclitaxel (albumin binding type) (hereinafter referred to as nab-P) combined with Apatinib (hereinafter referred to as AP) in platinum-resistant ovarian cancer cell line and xenograft models.

METHODS

SKOV-3/DDP cell line was selected as the research object in cytology experiment. Firstly, we divided it into three groups for experiments to explore the individual effects of nab-P and AP. a): Control group, blank control, no drug intervention; b): nab-P group, nab-P 40 μmol/l; c): AP group, AP 50 μmol/l (Drug doses were IC-50 values that detected by MTT assay). Apoptosis related protein (Bax, bcl-2), vascular related protein(p-VEGFR-2), invasion related protein (MMP-2) expression were detected by Western blot and Cellular immunofluorescence, the invasion ability of tumor cells were detected by Transwell and Cell scratch test. Based on these dates, secondly, establishing different doses of nab-P combined with Ap to explore the curative effect of combination therapy. a): Control group, blank control, no drug intervention; b): Group-1, nab-P 5 μmol/l + AP 10 μmol/l, c): Group-2, nab-P 4.5 μmol/l + AP 10 μmol/l, d): Group-3, nab-P 4 μmol/l + AP 10 μmol/l, e): nab-P group, nab-P 5 μmol/l, f): AP group, AP 10 μmol/l (MTT assay). The combination index was analyzed by Compusyn software, Western blot, Immunofluescence, Transwell and Cell scratch test also were also chose to observe of inhibition effect. Thirdly, we used xenograft models to verify the results of cytological experiments. Tumor-forming BALB/c female nude mice were randomly divided into 4 groups, a): Control group, no drug intervention, only saline injection, b): nab-P 20 mg/kg + AP 150 mg/kg, c): nab-P 18 mg/kg + AP 150 mg/kg, d): nab-P 16 mg/kg + AP 150 mg/kg (The doses were guided by the pharmaceutical manufacturers). The tumor growth curve was analyzed during the experiment. And the apoptosis related protein (Bax, bcl-2), angiogenesis related protein (CD31, p-VEGFR-2) and invasion related protein (MMP-2) were observed by Western blot, Immunofluescence and Immunohistochemistry to analysis the ant-tumor effects. The quality of life in nude mice were observed to analysed the drug-induced side effects.

RESULT

In the separate medication section, (1) The IC-50 value of nab-P was 45.53 ± 4.06 μmol/l, while the AP was 50.66 ± 4.96 umol/L (48 h). (2) The expressions of bcl-2 (nab-P group, AP group), p-VEGFR-2 (AP group), MMP-2(nab-P group, AP group) were higher than Control group, while Bax (nab-P group, AP group) lower (P < 0.01). (3) The cell invasive ability was decreased after the nab-P and AP intervation (P < 0.01). In the combination medication section, (1) Compusyn showed the Combination index (Cl) were all below 1 (Cl < 1), that means nab-P and AP are synergism. (2) The combination IC-50 value was nab-P 5.28 μmol/l + AP 10.56 μmol/l (48 h). (3) In the detection of related protein expression, the combination of drugs can improve the anti-tumor effect, otherwise, after combined with AP, when nab-P were reduced dose in proper quantity, there were no obvious different in drug effect. (4) After reducing the doses of nab-P, the average food intake of nude mice increased from 4.50 g ± 0.17 to 5.55 g ± 0.13, and the one-hour activity increased from 6.11 min ±0.16 to 6.34 min ±0.13.

CONCLUSION

nab-P, a chemotherapeutic agent, can play an anti-tumor role in platinum-resistant ovarian cancer, but it can cause adverse effects that increase with dose. When combined with AP, the two drugs have synergistic effect, which can improve the anti-tumor effects of single drug. In addition, when combined with AP, the doses of nab-P can be appropriately reduced under the standard of recommended to reduce the toxicity of chemotherapy drugs, without affecting the anti-tumor effect.

Survivin rs9904341 polymorphism significantly increased the risk of cancer: evidence from an updated meta-analysis of case-control studies

AIMS

Survivin, a member of inhibitor of apoptosis protein family, is involved in the regulation of cell cycle and apoptosis. Several studies inspected the association between survivin polymorphisms and the risk of various cancers, but the findings remain controversial. We conducted a meta-analysis intending to certify the association between survivin polymorphisms and cancer risk.

METHODS

All analyses were achieved using RevMan 5.3 software and STATA 14.1 software. Eligible studies were collected by comprehensive literature searching Web of Science, PubMed, Scopus, and Google scholar databases. Pooled estimates of odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the overall impact of survivin polymorphisms on cancer risk.

RESULTS

The overall analysis indicates that survivin rs9904341 polymorphism significantly increased the risk of cancer in homozygous codominant (OR 1.41, 95% CI 1.19-1.68, p = 0.0001, CC vs GG), dominant (OR 1.22, 95% CI 1.07-1.40, p = 0.003, CG+CC vs GG), recessive (OR 1.34, 95% CI 1.18-1.52, p < 0.0001, CC vs CG+GG), and allele (OR 1.20, 95% CI 1.09-1.31, p = 0.0001, C vs G) inheritance models tested. Stratified based on ethnicity revealed that rs9904341 variant significantly increased the risk of cancer in the Asian population. The findings did not support an association between rs1042489, rs2071214, rs8073069, and rs17878467 polymorphisms and risk of cancer.

CONCLUSIONS

The current study suggests that the survivin rs9904341 polymorphism may be associated with the risk of cancer either overall or in the Asian population. However, further larger and well-designed studies are warranted to evaluate this association in detail.

Anti-Tumorigenic Effects of Resveratrol in Lung Cancer Cells Through Modulation of c-FLIP

BACKGROUND

Resveratrol has been shown to have antioxidant and anti-proliferative properties in multiple cancer types. Here we demonstrate that H460 lung cancer cells are more susceptible to resveratrol treatment in comparison to human bronchial epithelial Beas-2B cells. Resveratrol decreases cell viability and proliferation, and induces significant apoptosis in H460 cells. The apoptosis observed was accompanied by an increase in hydrogen peroxide (H2O2) production, Bid, PARP and caspase 8 activation, and downregulation of pEGFR, pAkt, c-FLIP and NFkB protein expression. Furthermore, treatment with HH2O2 scavenger catalase significantly inhibited resveratrol-induced c-FLIP downregulation, caspase-8 activation and apoptosis. Overexpression of c-FLIP in H460 cells (FLIP cells) resulted in the inhibition of resveratrol-induced HH2O2 production, and a significant increase in resveratrolinduced apoptosis in comparison to H460 cells. In FLIP cells, catalase treatment did not rescue cells from a decrease in cell viability and apoptosis induction by resveratrol as compared to H460 cells. Resveratrol treatment also led to VEGF downregulation in FLIP cells. Furthermore, inhibition of pEGFR or pAkt using erlotinib and LY294002 respectively, enhanced the negative effect of resveratrol on FLIP cell viability and apoptosis. The reverse was observed when FLIP cells were supplemented with EGF, or transfected with WT-AKT plasmid; resulting in a 20% decrease in resveratrol-induced apoptosis. In addition, transfection with WT-AKT plasmid resulted in the inhibition of pro-apoptotic protein activation, and c-FLIP and pAkt downregulation.

CONCLUSION

Overall, resveratrol induced apoptosis in H460 lung cancer cells by specifically targeting pAkt and c-FLIP dowregulation by proteasomal degradation in a EGFR-dependent manner.

Glucosidase II beta subunit (GluIIβ) plays a role in autophagy and apoptosis regulation in lung carcinoma cells in a p53-dependent manner

PURPOSE

Glucosidase II plays a major role in regulating the post-translational modification of N-linked glycoproteins. Previously, we found that the beta subunit of glucosidase II (GluIIβ) levels are significantly increased in lung carcinoma tissues, indicating a potential role in lung tumorigenesis. Here, we investigated the role of GluIIβ in the regulation of autophagy and apoptosis in lung carcinoma- and immortalized human bronchial epithelial-derived cells.

METHODS

A selective glucosidase II inhibitor, bromoconduritol, was used to inhibit GluII enzyme activity and a siRNA-based technology was used to suppress the expression of the GluIIβ encoding gene PRKCSH in lung carcinoma cells differing in p53 status. Cell viability was assessed using a MTT assay, cell cycle progression was assessed using flow cytometry, autophagy was assessed using Western blotting and apoptosis was assessed using an annexin V-FITC/PI double labeling method.

RESULTS

We found that GluIIβ inhibition resulted in the induction of autophagy in all cell lines tested, but apoptosis in only wild-type p53 cells. We also found that GluIIβ inhibition dose-dependently decreased activation of the EGFR/RTK and PI3K/AKT signaling pathways. Although the apoptosis inducing effect of GluIIβ inhibition appeared to be p53-dependent, we found that a combined treatment with lysosomal inhibitors to block autophagy enhanced the apoptotic effect of GluIIβ inhibition in both wild-type p53 and p53-null cells.

CONCLUSIONS

Our data indicate that GluIIβ inhibition results in autophagy and apoptosis in lung carcinoma-derived cells, supporting the hypothesis that this enzyme may play a role in blocking these two tumor suppressive processes. Since blocking autophagy by lysosomal inhibitors enhanced the apoptosis-inducing effect of bromoconduritol, independent of p53 status, their combined use may hold promise for the treatment of cancer, particularly lung cancer.

Tripchlorolide induces autophagy in lung cancer cells by inhibiting the PI3K/AKT/mTOR pathway and improves cisplatin sensitivity in A549/DDP cells

Tripchlorolide (T4) has been shown to induce A549 lung cancer cell death predominantly by activating an autophagy pathway. However, the underlying mechanism remains unclear. Herein, we demonstrated that compared with T4 treatment alone, pretreatment with wortmannin (an inhibitor of phosphatidylinositol 3-kinase), perifosine (an inhibitor of AKT) or rapamycin (an inhibitor of mTOR) combined with a subsequent T4 treatment significantly impaired the cell viability of A549 and A549/DDP lung cancer cells. We found that either treatment scheme markedly reduced the activity of P13K and AKT. Expression of LC3II increased in parallel to the increase of the T4 concentration in both A549 and A549/DDP cells and was repressed by overexpression of AKT. The expression levels of PI3-K, PI3-P, AKT, TSC2, mTOR, p70S6K and 4E-BP1 were minimally affected by the wortmannin, perifosine, or rapamycin plus T4 treatments, but their phosphorylated products were greatly affected in A549 lung cancer cells and slightly affected in A549/DDP lung cancer cells. These results indicate that T4 induces autophagy in lung cancer cells by inhibiting the PI3K/AKT/mTOR signaling pathway. We further found that T4 decreased expression of MDR1 and improved cisplatin sensitivity of A549/DDP cells. Altogether, these results have meaningful implications for tumor therapy in the future.

Evaluation of uttroside B, a saponin from Solanum nigrum Linn, as a promising chemotherapeutic agent against hepatocellular carcinoma

We report, for the first time, the remarkable efficacy of uttroside B, a potent saponin from Solanum nigrum Linn, against liver cancer. The compound has been isolated and characterized from the leaves of Solanum nigrum Linn, a plant widely used in traditional medicine and is a rich resource of several anticancer molecules. Uttroside B, that comprises of β-D-glucopyranosyl unit at C-26 of the furostanol and β-lycotetraosyl unit at C-3, is ten times more cytotoxic to the liver cancer cell line, HepG2 (IC50: 0.5 μM) than sorafenib (IC50: 5.8 μM), the only FDA-approved drug for liver cancer. Moreover, it induces cytotoxicity in all liver cancer cell lines, irrespective of their HBV status, while being non-toxic to normal immortalized hepatocytes. It induces apoptosis in HepG2 cells by down-regulating mainly the activation of MAPK and mTOR pathways. The drastic reduction in HepG2-xenograft tumor size achieved by uttroside B in NOD-SCID mice and substantiation of its biological safety through both acute and chronic toxicity studies in Swiss albino mice warrants clinical validation of the molecule against hepatic cancer, for which, the chemotherapeutic armamentarium currently has limited weapons.

S-Nitrosylation of Bcl-2 Negatively Affects Autophagy in Lung Epithelial Cells

Autophagy is a catabolic cellular mechanism involving lysosomal degradation of unwanted cellular components. Interaction between Beclin-1 and Bcl-2 proteins is known to play a critical role in the initiation of autophagy. We report that malignantly transformed lung epithelial cells are resistant to autophagy and express lower basal levels of autophagic proteins, Beclin-1 and LC3-II as compared to non-tumorigenic cells. Additionally, increased levels of nitric oxide (NO) and Bcl-2 were observed in transformed cells. Nitric oxide was found to negatively regulate autophagy initiation and autophagic flux by nitrosylating Bcl-2 and stabilizing its interaction with Beclin-1, resulting in inhibition of Beclin-1 activity. An increase in the apoptotic initiator caspase-9 and the apoptosis and autophagy-associated kinase p38/MAPK in both cell types indicated possible autophagy-apoptosis crosstalk. Pre-treatments with ABT-737 (Bcl-2 inhibitor) and aminoguanidine (NO inhibitor), and transfection with a non-nitrosylable Bcl-2 cysteine double-mutant plasmid resulted in increased autophagic flux (LC3-II/p62 upregulation) corresponding with decreased S-nitrocysteine expression, thus corroborating the regulatory role of Bcl-2 S-nitrosylation in autophagy. In conclusion, our study reveals a novel mechanism of autophagy resistance via post-translational modification of Bcl-2 protein by NO, which may be critical in driving cellular tumorigenesis.

Metformin induces apoptosis by microRNA-26a-mediated downregulation of myeloid cell leukaemia-1 in human oral cancer cells

In recent years, population-based studies and retrospective analyses of clinical studies have shown that metformin treatment is associated with reduced cancer incidence and a decrease in cancer‑associated mortality. However, its mechanism of action remains to be fully understood. The present study demonstrates the effects of metformin on KB human oral cancer cells and explores the role of myeloid cell leukaemia‑1 (Mcl‑1) in metformin‑induced mitochondria‑dependent cellular apoptosis. It was demonstrated that metformin exposure caused significant suppression of KB cell proliferation and induced cell death. Furthermore, metformin induced apoptosis through the downregulation of Mcl‑1 in KB human oral cancer cells, and the overexpression of Mcl‑1 in metformin‑treated KB cells significantly increased cell viability. Consistently, Bax and Bim were upregulated in metformin‑treated cells. The results also reveal that microRNA (miR)‑26a expression was markedly increased by metformin. Subsequent to enforced miR‑26a expression in KB cells using miR‑26a mimics, cell viability and the level of Mcl‑1 decreased. These results suggest that the anti‑proliferative effects of metformin in KB cells may result partly from induction of apoptosis by miR-26a-induced downregulation of Mcl-1.

microRNA regulators of apoptosis in cancer

This brief review summarizes our current knowledge on the microRNAs that regulate apoptosis machinery and are potentially involved in the dysregulation or deregulation of apoptosis, a well known hallmark of cancer. microRNAs are critical regulators of the most important cellular processes, including apoptosis. Expression of microRNAs is found to be dysregulated in many malignancies, leading to apoptosis inhibition in cancer, or resistance to current therapies. To date, there are over 80 microRNAs directly involved in apoptosis regulation or dysregulation that can impact cancer detection, initiation, progression, invasion, metastasis or resistance to anti-cancer therapy. Development of microRNA-based therapeutic strategies is now taking shape in the clinic. Thus, these microRNAs represent potential targets or tools for cancer therapy in the future.

Anti-tumor activity of folate targeted biodegradable polymer-paclitaxel conjugate micelles on EMT-6 breast cancer model

BACKGROUND

Paclitaxel (PTX) is a first line chemotherapy drug for breast cancer. There have been few studies reported concerning the therapeutic efficacy of paclitaxel-conjugated polymeric micelles in breast cancer in vivo.

METHODS

Two kinds of PTX conjugate micelles, one of which (M(PTX)) contained 25 wt.% of PTX and the other (M(FA/PTX)) contained 22.5 wt.% of PTX and 1.4 wt.% of folate (FA), were prepared for cell apoptosis and anti-tumor activity evaluation on EMT-6 mice breast cancer models in comparison with 0.9 wt.% saline (control) and equivalent PTX. Cell apoptosis was analyzed by flow cytometry. Breast tumors were examined histologically with H&E staining and immunohistochemically by examining Bax and Bcl-2 expression. The survival status of tumor-bearing mice with different treatments was also examined.

RESULTS

On day 5 of the drug administration, the average tumor masses were 0.49, 0.33, 0.22, and 0.18 g for the control, PTX, M(PTX) and M(FA/PTX) groups, respectively. The inhibition rates of tumor growth calculated for the three drug groups were 32.6%, 51.6% and 62.3%, respectively. The percentage of cell apoptosis based on flow cytometry was 1.0%, 36.6%, 55.9% and 66.1%, respectively, which showed statistically significant differences (p<0.05) between three drug groups and the control group. Bcl-2 expression of PTX and M(FA/PTX) groups was lower than control group (p<0.05). Bax expression of drug groups was higher than control group (p<0.05). At an equivalent paclitaxel dose of 26.7 mg/kg, the average survival time was 33 days, 31 days, 34 days and 42 days, respectively (p<0.05).

CONCLUSION

The M(FA/PTX) have better anti-tumor activity and are promising in treatment of human breast cancers.

Silencing Daxx increases the anti-tumor activity of a TRAIL/shRNA Bcl-xL-expressing oncolytic adenovirus through enhanced viral replication and cellular arrest

We previously showed that an increase of cellular Bcl-xL mediates acquired resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and knockdown of Bcl-xL expression greatly sensitized TRAIL-induced cytotoxicity. Here, we show that Daxx downregulation increases the anti-tumorigenic activity through enhancement of viral replication and cellular arrest with combination of TRAIL/shBcl-xL-induced apoptosis. This study was conducted to determine the effect of Daxx downregulation on the anti-tumorigenesis induced by oncolytic adenovirus arming TRAIL or TRAIL/shRNA of Bcl-xL genes. Unlike the enhanced cancer cell death induced by exogenous TRAIL or TRAIL plus shRNA of Bcl-xL, oncolytic adenovirus expressing TRAIL or TRAIL plus shRNA of Bcl-xL did not show much enhanced cancer cell death compared to oncolytic adenovirus itself. On the other hand, enhanced cytotoxic cell death and viral replication was observed after infection with oncolytic adenovirus expressing TRAIL plus shRNA of Bcl-xL and shRNA of Daxx at the same construct. Then we realized that enhanced adenoviral replication through Daxx downregulation was caused by increased adenoviral E1A protein expression and Daxx downregulation also stimulated cellular arrest through p21/p53 accumulation. Taken all together, we have shown here that Daxx downregulation should be essentially needed for the increase of anti-tumor activity through enhancement of viral replication and cellular arrest with the combination of TRAIL/shBcl-xL-induced apoptosis and oncolytic adenovirus.

Phellinus linteus extract induces autophagy and synergizes with 5-fluorouracil to inhibit breast cancer cell growth

Phellinus linteus (PL) is a medicinal mushroom due to its several biological properties, including anticancer activity. However, the mechanisms of its anticancer effect remain to be elucidated. We evaluated the inhibitory effects of the ethanolic extract from the PL combined with 5-FU on MDA-MB-231 breast cancer cell line and to determine the mechanism of cell death. Individually, PL extract and 5-FU significantly inhibited the proliferation of MDA-MB-231 cells in a dose-dependent manner. PL extract (30 mg/mL) in combination with 5-FU (10 μg/mL) synergistically inhibited MDA-MB-231 cells by 1.8-fold. PL did not induce apoptosis, as demonstrated by the DNA fragmentation assay, the sub-G1 population, and staining with annexin V-FITC and propidium iodide. The exposure of MDA-MB-231 cells to PL extracts resulted in several confirmed characteristics of autophagy, including the appearance of autophagic vacuoles revealed by monodansylcadaverine staining, the formation of acidic vesicular organelles, autophagosome membrane association of microtubule-associated protein light chain 3 (LC3) characterized by cleavage of LC3 and its punctuate redistribution, and ultrastructural observation of autophagic vacuoles by transmission electron microscopy. We concluded that PL extracts synergized with low doses of 5-FU to inhibit triple-negative breast cancer cell growth and demonstrated that PL extract can induce autophagy-related cell death.

Epistatic interaction between adiponectin and survivin gene polymorphisms in endometrial carcinoma

Adiponectin appears to play an important role in the development and progression of several obesity-related malignancies. Also, overexpression of survivin, an inhibitor of apoptosis protein, is associated with increased risk of cancers. The aim of this study was to investigate the association between two polymorphisms in the adiponectin gene and endometrial cancer (EC) risk. We also investigated whether epistasis between surviving and adiponectin gene polymorphisms are associated with EC risk in an Iranian population. The samples comprised formalin-fixed, paraffin-embedded tissue sections obtained from the archive of the pathology department, Imam-Khomeini Hospital and Firouzgar hospital. After DNA extraction the genotyping was performed using PCR-RFLP technique. Single nucleotide polymorphisms (SNPs) in adiponectin (rs1063539, rs2241766) and survivin (rs9904341) gene were evaluated in the study. The increased frequency of ADIPOQ rs1063539C allele (CC+CG genotype) was associated with decreased EC risk [OR: 0.39(0.17-0.90)]. Survivin rs9904341C allele (CC+CG genotype) was associated with increased EC risk [crude OR: 2.75(1.27-5.95), adjusted OR: 2.93(1.27-6.76)]. We observed an epistatic interaction between survivin rs9904341 CC+CG genotype and ADIPOQ rs1063539 GG genotype increasing the risk of EC compared to those with other genotypes [OR: 4.86(1.88-12.54), P=0.001]. Our findings indicate that adiponectin might have a modulatory effect on survivin role and function in EC, which requires further investigation.

Destruxin B inhibits hepatocellular carcinoma cell growth through modulation of the Wnt/β-catenin signaling pathway and epithelial-mesenchymal transition

The aberrant activation of Wnt/β-catenin signaling plays an important role in the carcinogenesis and progression of hepatocellular carcinoma (HCC). Therefore, the Wnt/β-catenin signaling molecules are attractive candidates for the development of targeted therapies for this disease. The present study showed that destruxin B (DB) inhibits the proliferation and induces the apoptosis of HCC cells by decreasing the protein expression of anti-apoptotic Bcl-2 and Bcl-xL and increasing the expression of the proapoptotic protein Bax. More importantly, DB also attenuates Wnt-signaling in HCC cells by downregulating β-catenin, Tcf4, and β-catenin/Tcf4 transcriptional activity, which results in the decreased expression of β-catenin target genes, such as cyclin D1, c-myc, and survivin. Furthermore, DB affects the migratory and invasive abilities of Sk-Hep1 cells through the suppression of markers of the epithelial-mesenchymal transition (EMT). A synergistic anti-proliferative and migratory effect was achieved using the combination of DB and sorafenib in Sk-Hep1 cells. In conclusion, DB acts as a novel Wnt/β-catenin inhibitor and reduces the aggressiveness and invasive potential of HCC by altering the cells' EMT status and mobility. DB in combination with sorafenib may be considered for future clinical use for the management of metastatic HCC.

Immunity, inflammation and cancer: a leading role for adenosine

Cancer is a complex disease that is dictated by both cancer cell-intrinsic and cell-extrinsic processes. Adenosine is an ancient extracellular signalling molecule that can regulate almost all aspects of tissue function. As such, several studies have recently highlighted a crucial role for adenosine signalling in regulating the various aspects of cell-intrinsic and cell-extrinsic processes of cancer development. This Review critically discusses the role of adenosine and its receptors in regulating the complex interplay among immune, inflammatory, endothelial and cancer cells during the course of neoplastic disease.

Combination of bortezomib and mitotic inhibitors down-modulate Bcr-Abl and efficiently eliminates tyrosine-kinase inhibitor sensitive and resistant Bcr-Abl-positive leukemic cells

Emergence of resistance to Tyrosine-Kinase Inhibitors (TKIs), such as imatinib, dasatinib and nilotinib, in Chronic Myelogenous Leukemia (CML) demands new therapeutic strategies. We and others have previously established bortezomib, a selective proteasome inhibitor, as an important potential treatment in CML. Here we show that the combined regimens of bortezomib with mitotic inhibitors, such as the microtubule-stabilizing agent Paclitaxel and the PLK1 inhibitor BI2536, efficiently kill TKIs-resistant and -sensitive Bcr-Abl-positive leukemic cells. Combined treatment activates caspases 8, 9 and 3, which correlate with caspase-induced PARP cleavage. These effects are associated with a marked increase in activation of the stress-related MAP kinases p38MAPK and JNK. Interestingly, combined treatment induces a marked decrease in the total and phosphorylated Bcr-Abl protein levels, and inhibits signaling pathways downstream of Bcr-Abl: downregulation of STAT3 and STAT5 phosphorylation and/or total levels and a decrease in phosphorylation of the Bcr-Abl-associated proteins CrkL and Lyn. Moreover, we found that other mitotic inhibitors (Vincristine and Docetaxel), in combination with bortezomib, also suppress the Bcr-Abl-induced pro-survival signals and result in caspase 3 activation. These results open novel possibilities for the treatment of Bcr-Abl-positive leukemias, especially in the imatinib, dasatinib and nilotinib-resistant CML cases.

Association of survivin polymorphisms with tumor susceptibility: a meta-analysis

Background

The survivin polymorphisms have been shown to confer genetic susceptibility to various tumors, but the results are inconsistent. In order to accomplish a more precise estimation of the relationship, a meta-analysis was performed.

Results

For rs9904341, a significantly increased tumor risk was found in overall meta-analysis under C/C vs. G/G (OR = 1.40, 95% CI = 1.13–1.74, p = 0.002), dominant (OR = 1.18, 95% CI = 1.01–1.38, p = 0.039) and recessive (OR = 1.34, 95% CI = 1.13–1.58, p = 0.001) genetic models and Asians group. In subgroup analyses of tumor types, we found a significant association between this SNP and an increased risk of gastric, colorectal, bladder and other tumors as well as a decreased risk of hepatocellular cancer. For rs17878467, a significantly decreased tumor risk was identified in overall meta-analysis for allele contrast (T vs. C: OR = 0.69, 95% CI = 0.51–0.92, p = 0.012), C/T vs. C/C (OR = 0.61, 95% CI = 0.42–0.88, p = 0.009) and dominant (OR = 0.62, 95% CI = 0.43–0.88, p = 0.007) genetic models and Asians group. For rs2071214, we found a significant association between this SNP and an increased tumor risk in overall meta-analysis under G/G vs. A/A (OR = 1.51, 95% CI = 1.04–2.18, p = 0.029) and recessive (OR = 1.54, 95% CI = 1.07–2.22, p = 0.020) genetic models and Asians group. Besides, there was a significant association of rs8073069 with an increased tumor risk under recessive genetic model (OR = 1.37, 95% CI = 1.01–1.84, p = 0.040), while no significant association between rs1042489 and tumor risk was detected.

Conclusions

The survivin rs9904341 most likely contributed to increased susceptibility to tumor in Asians as well as to gastric, colorectal and bladder cancers. As for rs17878467, the T allele might be a protective factor for tumor, especially in Asians. Moreover, the survivin rs8073069 and rs2071214 seemed to be associated with an increased tumor risk in Asians, while there was no association between the survivin rs1042489 and tumor risk.

Survivin gene promoter -31 G/C polymorphism is associated with Wilms tumor susceptibility in Serbian children

Survivin, an apoptotic inhibitor, is overexpressed in various types of cancer. Mechanisms of survivin upregulation are still poorly understood, but single nucleotide polymorphisms in the survivin gene promoter have been shown to modulate survivin expression and consequently the risk for some types of cancer. The aim of the present study was to investigate whether survivin promoter -31 G/C and -241 C/T polymorphisms could represent susceptibility factors for Wilms tumor (WT) development in Serbian population. Genotype and allele frequencies for the 2 polymorphisms in survivin promoter have been analyzed by polymerase chain reaction/restriction fragment length polymorphism in 59 WT patients and 82 controls. The frequencies of alleles and genotypes were significantly different between patients and controls for the -31 G/C polymorphism. Individuals with CC and CG genotypes had significantly decreased risk of WT compared with GG individuals (odds ratio 0.26, 95% confidence interval, 0.07-0.96; odds ratio 0.30, 95% confidence interval, 0.15-0.60). There was also a statistically significant difference in genotype frequencies between intermediate and high-risk prognostic groups (P=0.015). The -241 C/T polymorphism did not show association with WT susceptibility. Our findings suggest that the G allele at -31 survivin gene promoter position is associated with a significantly higher cancer risk in Serbian children, with a gene dosage effect.

TRAIL resistance in human neuroblastoma SK-N-AS cells is dependent on protein kinase C and involves inhibition of caspase-3 proteolytic processing

Neuroblastoma is the most common solid extracranial cancer form in childhood with an etiology that is mostly unknown. Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been proposed as a promising future anticancer drug candidate, highly malignant neuroblastoma has been reported to acquire TRAIL resistance by mechanisms that are poorly understood. Here, we show by western blot analysis, and live cell imaging using anchored FRET sensors, that the resistance to TRAIL-induced apoptosis in human neuroblastoma SK-N-AS cells depends on an incomplete processing of procaspase-3, generating an immature and catalytically inactive 21 kDa fragment. We have previously shown that the naturally occurring compound curcumin can sensitize SK-N-AS cells to TRAIL. In the present study, we show that curcumin also has a similar effect on human neuroblastoma SHEP1 cells. Furthermore, we show that curcumin and TRAIL co-treatment induces complete maturation and activation of caspase-3 in both cell lines. The mechanisms behind this effect seem to be dependent on protein kinase C (PKC), since inhibition of PKC using bisindolylmaleimide XI, could also sensitize these cells to TRAIL through a similar effect on caspase-3 activation. Moreover, TRAIL co-treatment with bisindolylmaleimide XI or curcumin resulted in down-regulation of X-linked inhibitor of apoptosis protein. In conclusion, our study shows that PKC can be involved in TRAIL resistance in human neuroblastoma cells by preventing caspase-3 maturation.

Preclinical evaluation of destruxin B as a novel Wnt signaling target suppressing proliferation and metastasis of colorectal cancer using non-invasive bioluminescence imaging

In continuation to our studies toward the identification of direct anti-cancer targets, here we showed that destruxin B (DB) from Metarhizium anisopliae suppressed the proliferation and induced cell cycle arrest in human colorectal cancer (CRC) HT29, SW480 and HCT116 cells. Additionally, DB induced apoptosis in HT29 cells by decreased expression level of anti-apoptotic proteins Bcl-2 and Bcl-xL while increased pro-apoptotic Bax. On the other hand, DB attenuated Wnt-signaling by downregulation of β-catenin, Tcf4 and β-catenin/Tcf4 transcriptional activity, concomitantly with decreased expression of β-catenin target genes cyclin D1, c-myc and survivin. Furthermore, DB affected the migratory and invasive ability of HT29 cells through suppressed MMPs-2 and -9 enzymatic activities. We also found that DB targeted the MAPK and/or PI3K/Akt pathway by reduced expression of Akt, IKK-α, JNK, NF-κB, c-Jun and c-Fos while increased that of IκBα. Finally, we demonstrated that DB inhibited tumorigenesis in HT29 xenograft mice using non-invasive bioluminescence technique. Consistently, tumor samples from DB-treated mice demonstrated suppressed expression of β-catenin, cyclin D1, survivin, and endothelial marker CD31 while increased caspase-3 expression. Collectively, our data supports DB as an inhibitor of Wnt/β-catenin/Tcf signaling pathway that may be beneficial in the CRC management.

Role of MMP-2 in the regulation of IL-6/Stat3 survival signaling via interaction with α5β1 integrin in glioma

Matrix metalloproteinase-2 (MMP-2) has pivotal role in the degradation of extracellular matrix, and thereby enhances the invasive, proliferative and metastatic potential in cancer. Knockdown of MMP-2 using MMP-2 small interfering RNA (pM) in human glioma xenograft cell lines 4910 and 5310 decreased cell proliferation compared with mock and pSV (scrambled vector) treatments, as determined by 5-bromo-2'-deoxyuridine incorporation, Ki-67 staining and clonogenic survival assay. Cytokine array and western blotting using tumor-conditioned media displayed modulated secretory levels of various cytokines including granulocyte-macrophage colony-stimulating factor, interleukin-6 (IL-6), IL-8, IL-10, tumor necrosis factor-α, angiogenin, vascular endothelial growth factor and PDGF-BB in MMP-2 knockdown cells. Further, cDNA PCR array indicated potential negative regulation of Janus kinase/Stat3 pathway in pM-treated cells. Mechanistically, MMP-2 is involved in complex formation with α5 and β1 integrins and MMP-2 downregulation inhibited α5β1 integrin-mediated Stat3 phosphorylation and nuclear translocation. Electrophoretic mobility shift assay and chromatin immunoprecipitation assays showed inhibited Stat3 DNA-binding activity and recruitment at CyclinD1 and c-Myc promoters in pM-treated cells. In individual experiments, IL-6 or siRNA-insensitive MMP-2 overexpression by pM-FL-A141G counteracted and restored the pM-inhibited Stat3 DNA-binding activity, suggesting IL-6/Stat3 signaling suppression in pM-treated 4910 and 5310 cells. MMP-2/α5β1 binding is enhanced in human recombinant MMP-2 treatments, resulting in elevated Stat3 DNA-binding activity and recruitment on CyclinD1 and c-Myc promoters. Activation of α5β1 signaling by Fibronectin adhesion elevated pM-inhibited Stat3 phosphorylation whereas blocking α5β1 abrogated constitutive Stat3 activation. In vivo experiments with orthotropic tumor model revealed the decreased tumor size in pM treatment compared with mock or pSV treatments. Immunofluorescence studies in tumor sections corroborated our in vitro findings evidencing high expression and co-localization of MMP-2/α5β1, which is decreased upon pM treatment along with significantly reduced IL-6, phospho-Stat3, CyclinD1, c-Myc, Ki-67 and PCNA expression levels. Our data indicate the possible role of MMP-2/α5β1 interaction in the regulation of α5β1-mediated IL-6/Stat3 signaling activation and signifies the therapeutic potential of blocking MMP-2/α5β1 interaction in glioma treatment.

Survivin gene polymorphism association with papillary thyroid carcinoma

Survivin expression is correlated with suppression of apoptosis in human solid tumors. A polymorphism at position -31 (G/C) (rs 9904341) has been associated with cancer risk in several studies. We evaluated the correlation of this polymorphism with the risk of papillary thyroid carcinoma (PTC) in an Irananian population. The cases consisted of patients with PTC (n=123) and normal controls, composed of non-related healthy people (n=131). The frequency of GC or CC genotype in patients with PTC was significantly higher than in the controls [GC+CC vs GG, p=0.02 OR; 1.7, 95%CI (1.05-3.04)]. There was a significant difference between patients with more aggressive clinical manifestations, including lymphatic involvement compared to the controls [GC+CC vs GG, p=0.0006, OR; 3.7, 95%CI (1.6-9.2)]. The presence of C allele was significantly associated with the presence of more profound manifestations, including lymph node involvement, vascular involvement and multifocality.

Association between survivin -31G > C promoter polymorphism and cancer risk: a meta-analysis

Survivin is an inhibitor of apoptosis protein and has a crucial role in the development of cancer. The survivin -31G>C (rs9904341) promoter polymorphism influences survivin expression and has been implicated in cancer risk. However, conflicting results have been published from studies on the association between survivin -31G>C polymorphism and the risk of cancer. To clarify the role of this polymorphism in cancer, we performed a meta-analysis of all available and relevant published studies, involving a total of 3485 cancer patients and 3964 control subjects. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the associations. The overall results indicated that the variant genotypes were associated with a significantly increased cancer risk (CC vs GG: OR=1.58, 95% CI=1.20-2.10; CC/GC vs GG: OR=1.23, 95% CI=1.00-1.51; CC vs GG/GC: OR=1.51, 95% CI=1.23-1.85). In the stratified analyses, significantly increased risk was associated with the Asian populations (CC vs GG: OR=1.67, 95% CI=1.16-2.40; CC vs GG/GC: OR=1.50, 95% CI=1.17-1.91). We also performed the analyses by cancer type, and no statistical association was observed. The results suggest that the survivin -31G>C promoter polymorphism might be associated with an increased risk of cancer, especially in the Asian populations.

Functional promoter -31G>C variant in survivin gene is associated with risk and progression of renal cell cancer in a Chinese population

Background

Survivin is an inhibitor of apoptosis protein and is involved in the occurrence and progression of human malignancies. Recently, a functional polymorphism (−31G>C, rs9904341) in the promoter of survivin has been shown to influence its expression and confer susceptibility to different types of cancer. The present study was aimed to investigate whether the polymorphism also influences susceptibility and progression of renal cell cancer (RCC) in a Chinese population.

Methods

We genotyped this polymorphism using the TaqMan assay in a case-control study comprised of 710 RCC patients and 760 controls. The logistic regression was used to assess the genetic association with occurrence and progression of RCC.

Results

Compared with the genotypes containing G allele (GG and GC), we found a statistically significant increased occurrence of RCC associated with the CC genotype [P = 0.006, adjusted odds ratio (OR) = 1.38, 95% confidence interval (CI) = 1.08–1.76]. The polymorphism was associated with risk of developing advanced stage (OR = 2.02, 95%CI = 1.34–3.07) and moderately differentiated (OR = 1.75; 95%CI = 1.20–2.54) RCC. Furthermore, the patients carrying the CC genotype had a significantly greater prevalence of high clinical stage disease (P_trend = 0.003). Similar results were also observed when we restricted the analysis to clear cell RCC, a major histological type of RCC.

Conclusions

Our results suggest that the functional −31G>C polymorphism in the promoter of survivin may influence the susceptibility and progression of RCC in the Chinese population. Large population-based prospective studies are required to validate our findings.

5-Fluorouracil-loaded poly(ε-caprolactone) nanoparticles combined with phage E gene therapy as a new strategy against colon cancer

This work aimed to develop a new therapeutic approach to increase the efficacy of 5-fluorouracil (5-FU) in the treatment of advanced or recurrent colon cancer. 5-FU-loaded biodegradable poly(ε-caprolactone) nanoparticles (PCL NPs) were combined with the cytotoxic suicide gene E (combined therapy). The SW480 human cancer cell line was used to assay the combined therapeutic strategy. This cell line was established from a primary adenocarcinoma of the colon and is characterized by an intrinsically high resistance to apoptosis that correlates with its resistance to 5-FU. 5-FU was absorbed into the matrix of the PCL NPs during synthesis using the interfacial polymer disposition method. The antitumor activity of gene E from the phage ϕX174 was tested by generating a stable clone (SW480/12/E). In addition, the localization of E protein and its activity in mitochondria were analyzed. We found that the incorporation of 5-FU into PCL NPs (which show no cytotoxicity alone), significantly improved the drug's anticancer activity, reducing the proliferation rate of colon cancer cells by up to 40-fold when compared with the nonincorporated drug alone. Furthermore, E gene expression sensitized colon cancer cells to the cytotoxic action of the 5-FU-based nanomedicine. Our findings demonstrate that despite the inherent resistance of SW480 to apoptosis, E gene activity is mediated by an apoptotic phenomenon that includes modulation of caspase-9 and caspase-3 expression and intense mitochondrial damage. Finally, a strongly synergistic antiproliferative effect was observed in colon cancer cells when E gene expression was combined with the activity of the 5-FU-loaded PCL NPs, thereby indicating the potential therapeutic value of the combined therapy.

Association of survivin gene polymorphism with endometrial cancer

OBJECTIVE

Survivin is an inhibitor of apoptosis protein, which is up-regulated in endometrial cancer (EC). A promoter region polymorphism (-31G/C) in the survivin gene has been reported as a modulator of gene expression. The aim of this study was to explore the frequency of survivin -31G/C polymorphism in tumor tissues from patients with EC in an Iranian population compared to that of healthy controls.

MATERIALS AND METHODS

Paraffin-embedded tissue sections from patients diagnosed with EC (n = 31) and healthy controls (n = 30) were examined. Genotyping for survivin -31G/C polymorphism was performed using polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP).

RESULTS

The presence of allele C was found to be significantly increased in EC tissues compared to the healthy tissues (GG vs GC + CC, P = 0. 01; OR, 3.6; 95% CI, 1.1-11.9).

CONCLUSION

Our data are in keeping with a previous finding regarding the role of survivin gene polymorphism in malignancies. This finding highlights the role of survivin in pathogenesis of various carcinomas, which might have therapeutic implications.

Functional polymorphisms in promoter survivin gene and its association with susceptibility to bladder cancer in North Indian cohort

Survivin is a member of novel inhibitor of apoptosis protein family which expressed in human cancers. The molecular detection of bladder cancer by targeting Survivin as a novel marker may be useful in the occurrence and progression of cancer. We genotyped Survivin -31G>C, -1547A>G and -241C>T by PCR-restriction fragment length polymorphism to evaluate the risk of bladder cancer (BC) in 200 BC patients and 200 healthy controls from North Indian cohort. We observed significant increased BC risk associated with variant CC genotype of Survivin -31G>C having 2.6 fold risk. The variant genotype of Survivin -1547A>G was significantly associated with BC risk (P = 0.047). In case of Survivin -241C>T the protective genotype for BC was heterozygous (P = 0.035). Smoking significantly modulated the risk in patients with Survivin -1547A>G polymorphism. Variant as well as hetero genotype of Survivin -31G>C was associated with reduced risk of recurrence (HR = 0.22 and 0.35) in BC patients receiving BCG treatment thus showing least survival. Furthermore, the haplotype analysis revealed C-A-T haplotype to be associated with reduced BC risk. Our findings suggested that the functional polymorphism -31G>C, -1547A>G and -241C>T in the promoter of Survivin gene may play a significant role in mediating the BC risk among North Indian cohort.

Tripchlorolide induces cell death in lung cancer cells by autophagy

It has been demonstrated that triptolide inhibits the growth of several types of cancer cells in vitro and prevents tumor growth in vivo by inducing apoptosis and autophagy. Here we showed that Tripchlorolide (T4) significantly suppressed the proliferation of A549 cells in a dose- and time-dependent manner. This suppressive effect was diminished when cells were pretreated with 3-Methylamphetamine (3-MA). After the cells were treated with T4, the LC3 II protein expression was significantly increased, and autophagosomes were observed by TEM. However, almost no apoptosis was observed in A549 treated with T4. These results suggest that T4 induces A549 cell death predominantly through the activation of the autophagy pathway instead of the apoptosis pathway.

Effects of Ginkgo biloba extract EGb761 on human colon adenocarcinoma cells

AIMS

To investigate the effect of Ginkgo biloba extract (EGb761) on cell proliferation and apoptosis in human colon cancer cells.

METHODS

Human colon cancer cell lines (HT-29) were cultured and incubated with various concentrations (0-320 mg/l) of EGb 761 solution for up to 72 h. Cell viability, cell apoptosis, cell cycle, expression of caspase-3, the mRNA levels of p53, and Bcl-2 were assessed.

RESULTS

EGb 761 inhibited the growth of HT-29 cells in a time-dose-dependent manner. At 80 and 320 mg/L, EGb 761 increased the number of cells in the G0/G1 phase and reduced cells in the G2/M and S phase. EGb 761 treatment also increased the apoptosis ratio of the HT-29 cells. EGb 761 treatment was associated with an increase in caspase-3 activities, reduction in bcl-2 mRNA expression and elevation in p53 mRNA expression.

CONCLUSION

EGb 761 inhibits the progression of human colon cancer cells. Its therapeutic effect may be related to enhanced caspase-3 activities, up-regulation of p53 and down-regulation of bcl-2 genes.