Survivin-mediated cancer cell migration through GRP78 and epithelial-mesenchymal transition (EMT) marker expression in Mahlavu cells

Decoding the roles of heat shock proteins in liver cancer

Hepatocellular carcinoma (HCC) is one of the most common gastrointestinal malignancies, characterized by insidious onset and high propensity for metastasis and recurrence. Apart from surgical resection, there are no effective curative methods for HCC in recent years, due to resistance to radiotherapy and chemotherapy. Heat shock proteins (HSP) play a crucial role in maintaining cellular homeostasis and normal organism development as molecular chaperones for intracellular proteins. Both basic research and clinical data have shown that HSPs are crucial participants in the HCC microenvironment, as well as the occurrence, development, metastasis, and resistance to radiotherapy and chemotherapy in various malignancies, particularly liver cancer. This review aims to discuss the molecular mechanisms and potential clinical value of HSPs in HCC, which may provide new insights for HSP-based therapeutic interventions for HCC.

PI3K δ inhibitor PI-3065 induces apoptosis in hepatocellular carcinoma cells by targeting survivin

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide, and its clinical treatment remains challenging. The development of new treatment regimens is important for effective HCC treatment. Phosphoinositide 3-kinase (PI3K) is a lipid kinase that plays an important role in cell growth and metabolism and is overexpressed in nearly 50% of patients with HCC. Studies have shown that PI-3065, a small-molecule inhibitor of phosphatidylinositol 3-kinase delta, significantly inhibits solid breast cancer. However, its antitumor effects against HCC and the underlying mechanisms remain unclear. In the present study, we found that PI-3065 dose- and time-dependently reduced HCC cell viability and induced apoptosis while posing no obvious apoptotic toxicity in normal liver cells. Further mechanistic analysis showed that PI-3065 induced apoptosis mainly by inhibiting survivin protein expression, decreasing mitochondrial membrane potential, and promoting cytochrome C release. Simultaneously, PI-3065 markedly suppressed the colony formation, migration, and epithelial-mesenchymal transition abilities of HCC cells. Furthermore, transplantation of nude mice with HCC tumors showed that PI-3065 inhibits HCC tumor growth in vivo by targeting survivin. In summary, PI-3065 specifically inhibited survivin expression and exerted anti-HCC activity in vivo and in vitro, suggesting that it may serve as an effective antitumor drug for HCC treatment, which warrants further study.

Development of a cancer cells self‑activating and miR‑125a‑5p expressing poly‑pharmacological nanodrug for cancer treatment

Cancer cells can acquire resistance to targeted therapeutic agents when the designated targets or their downstream signaling molecules develop protein conformational or activity changes. There is an increasing interest in developing poly-pharmacologic anticancer agents to target multiple oncoproteins or signaling pathways in cancer cells. The microRNA 125a-5p (miR-125a-5p) is a tumor suppressor, and its expression has frequently been downregulated in tumors. By contrast, the anti-apoptotic molecule BIRC5/SURVIVIN is highly expressed in tumors but not in the differentiated normal tissues. In the present study, the development of a BIRC5 gene promoter-driven, miR-125a-5p expressing, poly-L-lysine-conjugated magnetite iron poly-pharmacologic nanodrug (pL-MNP-pSur-125a) was reported. The cancer cells self-activating property and the anticancer effects of this nanodrug were examined in both the multidrug efflux protein ABCB1/MDR1-expressing/-non-expressing cancer cells in vitro and in vivo. It was demonstrated that pL-MNP-pSur-125a decreased the expression of ERBB2/HER2, HDAC5, BIRC5, and SP1, which are hot therapeutic targets for cancer in vitro. Notably, pL-MNP-pSur-125a also downregulated the expression of TDO2 in the human KB cervical carcinoma cells. PL-MNP-pSur-125a decreased the viability of various BIRC5-expressing cancer cells, regardless of the tissue origin or the expression of ABCB1, but not of the human BIRC5-non-expressing HMEC-1 endothelial cells. In vivo, pL-MNP-pSur-125a exhibited potent antitumor growth effects, but without inducing liver toxicity, in various zebrafish human-ABCB1-expressing and ABCB1-non-expressing tumor xenograft models. In conclusion, pL-MNP-pSur-125a is an easy-to-prepare and a promising poly-pharmacological anticancer nanodrug that has the potential to manage numerous malignancies, particularly for patients with BIRC5/ABCB1-related drug resistance after prolonged chemotherapeutic treatments.

Molecular Chaperones in Cancer Stem Cells: Determinants of Stemness and Potential Targets for Antitumor Therapy

Cancer stem cells (CSCs) are a great challenge in the fight against cancer because these self-renewing tumorigenic cell fractions are thought to be responsible for metastasis dissemination and cases of tumor recurrence. In comparison with non-stem cancer cells, CSCs are known to be more resistant to chemotherapy, radiotherapy, and immunotherapy. Elucidation of mechanisms and factors that promote the emergence and existence of CSCs and their high resistance to cytotoxic treatments would help to develop effective CSC-targeting therapeutics. The present review is dedicated to the implication of molecular chaperones (protein regulators of polypeptide chain folding) in both the formation/maintenance of the CSC phenotype and cytoprotective machinery allowing CSCs to survive after drug or radiation exposure and evade immune attack. The major cellular chaperones, namely heat shock proteins (HSP90, HSP70, HSP40, HSP27), glucose-regulated proteins (GRP94, GRP78, GRP75), tumor necrosis factor receptor-associated protein 1 (TRAP1), peptidyl-prolyl isomerases, protein disulfide isomerases, calreticulin, and also a transcription heat shock factor 1 (HSF1) initiating HSP gene expression are here considered as determinants of the cancer cell stemness and potential targets for a therapeutic attack on CSCs. Various approaches and agents are discussed that may be used for inhibiting the chaperone-dependent development/manifestations of cancer cell stemness.

Vascular Endothelial Growth Inhibitor, a Cytokine of the Tumor Necrosis Factor Family, is Associated With Epithelial-Mesenchymal Transition in Renal Cell Carcinoma

Previous studies have revealed that the activation of the epithelial-mesenchymal transition (EMT) endows metastatic properties upon cancer cells to promote invasion and migration. In this study, immunohistochemical analysis was performed in 50 cases of clear cell renal cell carcinoma (RCC) and paired normal kidney tissues. We detected the expression of vascular endothelial growth inhibitor (VEGI) and EMT markers (E-cadherin, fibronectin, and Slug) and recorded the clinical, pathologic, and follow-up (median follow-up: 79.0 mo) information. The expression of VEGI and E-cadherin was significantly lower in RCC tissues compared with normal kidney tissues (P<0.001). However, the expression of fibronectin and Slug was higher in RCC tissues (P<0.05). VEGI and EMT marker expression marginally differed in tumor size and stage. Significant differences were found in the pathologic grade (P<0.05). The Spearman correlation analysis suggested a positive correlation between VEGI and E-cadherin (r=0.451, P<0.01). A negative correlation was shown between VEGI and fibronectin (r=-0.465, P<0.01). There was also a negative correlation between VEGI and Slug (r=-0.758, P<0.01). During the 79.0 months (range, 7 to 119 mo) of follow-up, 6 patients died due to RCC, and the tumor-free survival rate was 88% (44/50). We did not find a significant correlation between VEGI/EMT markers (E-cadherin, fibronectin, and Slug) and overall survival (P>0.05). Our findings indicate that VEGI plays an important role in EMT in RCC. It suggests that VEGI may be investigated as a disease biomarker and therapeutic target in RCC.

Proteomic biomarkers in body fluids associated with pancreatic cancer

Pancreatic cancer (PC) is a highly malignant disease that represents the fourth leading cancer-related death worldwide. There has been very little improvement in survival rates over recent years, and surgical resection remains the only reliable curative approach. Factors that contribute to this dismal prognosis for PC include its rapid progression and invasion, the absence of specific symptoms, and the little impact of available chemotherapy. Importantly, the management of this malignancy is also limited by the lack of highly specific and sensitive biomarkers for its diagnosis and follow-up, and their identification is therefore considered a promising strategy to improve outcomes in these patients. Numerous translational studies have explored the usefulness of body fluids as a non-invasive source of PC-specific biomarkers, and innovations in proteomic methods and technologies have provided a myriad of protein biomarkers for different cancers. The adoption of a proteomic approach has improved understanding of the biology of PC and contributed to the potential identification of protein biomarkers for this disease. This review considers the most recent research efforts to develop novel proteomic biomarkers in body fluids for PC.

P4HB promotes HCC tumorigenesis through downregulation of GRP78 and subsequent upregulation of epithelial-to-mesenchymal transition

P4HB and GRP78 are molecular chaperones involved in cellular response to ER stress. They have been linked to cancer progression; however, their roles in hepatocellular carcinoma (HCC) are largely unclear. In this study, we found that P4HB is overexpressed in human HCC tissues and cell lines. Higher tumoral P4HB levels are correlated with more advanced disease and poorer survival. GRP78 expression is inversely correlated with P4HB in human HCC tissues, and downregulated by P4HB in HCC cell lines. P4HB overexpression promotes HCC cell growth, migration, invasion and epithelial-to-mesenchymal transition (EMT) in vitro. GRP78 overexpression not only inhibits HCC cell growth, migration, invasion and EMT, but also antagonizes the oncogenic effects of P4HB overexpression. Furthermore, P4HB silencing inhibits HCC tumorigenesis in vivo. Taken together, our results provided evidence that P4HB promotes HCC progression through downregulation of GRP78 and subsequent upregulation of EMT.

Lentiviral CRISPR/Cas9 nickase vector mediated BIRC5 editing inhibits epithelial to mesenchymal transition in ovarian cancer cells

BIRC5 encodes the protein survivin, a member of the inhibitor of apoptosis family. Survivin is highly expressed in a variety of cancers but has very low expression in the corresponding normal tissues, and its expression is often associated with tumor metastasis and chemoresistance. We report that survivin was highly expressed in ovarian cancer and strongly correlated with patient overall poor survival. For the first time, we provide experimental evidence that survivin is involved in epithelial to mesenchymal transition (EMT) in ovarian cancer cells. Lentiviral CRISPR/Cas9 nickase vector mediated BIRC5 gene editing led to the inhibition of EMT by upregulating epithelial cell marker, cytokeratin 7 and downregulating mesenchymal markers: snail2, β-catenin, and vimentin in both ovarian cancer SKOV3 and OVCAR3 cells. Consistent with this molecular approach, pharmacological treatment of ovarian cancer cells using a small molecule survivin inhibitor, YM155 also inhibited EMT in these ovarian cancer cell lines. Overexpression of BIRC5 promoted EMT in SKOV3 cells. Using molecular or pharmacological approaches, we found that cell proliferation, migration, and invasion were significantly inhibited following BIRC5 disruption in both cell lines. Inhibition of BIRC5 expression also sensitized cell responses to paclitaxel treatment. Moreover, loss of BIRC5 expression attenuated TGFβ signaling in both SKOV3 and OVCAR3 cells. Collectively, our studies demonstrated that disruption of BIRC5 expression inhibited EMT by attenuating the TGFβ pathway in ovarian cancer cells.

Survivin downregulation using siRNA nanoliposomes inhibits cell proliferation and promotes the apoptosis of MHCC-97H hepatic cancer cells: An in vitro and in vivo study

At present, survivin is one of the most cancer-specific proteins that has been identified. The present study aimed to investigate the antitumor effects of novel survivin small interfering RNA (siRNA) nanoliposomes targeting survivin in human hepatocellular carcinoma MHCC-97H cells and xenograft mouse models. Survivin-targeted siRNA nanoliposomes were prepared and transfected into MHCC-97H cells and MHCC-97H-bearing nude mice. Survivin expression was analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting. Cell viability was analyzed using an MTT assay and apoptosis was evaluated using Hoechst and Annexin V-fluorescein isothiocyanate/propidium iodide staining. Tumor growth in MHCC-97H-bearing mice was monitored following treatment and tumor samples were obtained for survivin expression analysis using RT-qPCR, western blotting and immunohistochemistry staining. Survivin expression levels were significantly downregulated by nanoliposome-mediated survivin siRNA delivery and this was associated with a significant inhibition of cell growth and an increase in the apoptosis of MHCC-97H cells. Downregulation of survivin expression using survivin siRNA nanoliposomes inhibited tumor growth in the MHCC-97H xenograft models without significant treatment-associated toxicity. Therefore, a cationic nanoliposome-based survivin siRNA delivery system was constructed and demonstrated to be efficient for survivin siRNA delivery in in vitro and in vivo studies. These results demonstrate that survivin downregulation was able to significantly attenuate cell proliferation and induce the apoptosis of MHCC-97H cells, as well as inhibit tumor cell growth in MHCC-97H xenograft models, indicating that survivin suppression using siRNA may contribute to the inhibition of tumor development by suppressing cell proliferation and promoting apoptosis.

Androgen receptor variation affects prostate cancer progression and drug resistance

Significant therapeutic progress has been made in treating prostate cancer in recent years. Drugs such as enzalutamide, abiraterone, and cabazitaxel have expanded the treatment armamentarium, although it is not completely clear which of these drugs are the most-effective option for individual patients. Moreover, such advances have been tempered by the development of therapeutic resistance. The purpose of this review is to summarize the current literature pertaining to the biochemical effects of AR variants and their consequences on prostate cancer therapies at both the molecular level and in clinical treatment. We address how these AR splice variants and mutations affect tumor progression and therapeutic resistance and discuss potential novel therapeutic strategies under development. It is hoped that these therapies can be administered with increasing precision as tumor genotyping methods become more sophisticated, thereby lending clinicians a better understanding of the underlying biology of prostate tumors in individual patients.

IWR-1 inhibits epithelial-mesenchymal transition of colorectal cancer cells through suppressing Wnt/β-catenin signaling as well as survivin expression

Aberrant activation of Wnt/β-catenin signaling is frequently observed in patients with colorectal cancer (CRC) and is considered a major determinant of CRC pathogenesis. CRC pathogenesis is particularly accompanied by epithelial-mesenchymal transition (EMT) and survivin expression. Here, we investigated the potential and mechanism of a novel Wnt/β-catenin inhibitor IWR-1 to suppress tumor metastasis in relation with EMT and survivin expression. We first determined the EMT reversal effects of IWR-1 in in vitro (HCT116 and HT29 cells) and ex vivo (specimens of CRC patients) CRC models. It was shown that IWR-1 inhibited cell proliferation and EMT even in the presence of TNF-α-induced cancer cell stimulation. IWR-1 also significantly suppressed cell migration, invasion, and matrix metalloproteinase activities of CRC cell lines. Furthermore, we showed the evidence that IWR-1 provides EMT reversal effects by directly suppressing survivin expression by the followings: 1) IWR-1 could not completely inhibit EMT in survivin-overexpressing HCT116 cells, 2) EMT reversal effects of IWR-1 were more pronounced in survivin-suppressed cells, and 3) Survivin promoter assay directly identified the survivin promoter region responsible for inhibition of survivin transcription by IWR-1. Taken altogether, our results demonstrate that IWR-1 has the potential to suppress tumor metastasis by inhibiting Wnt/β-catenin pathway as well as survivin expression. Therefore, IWR-1 could be considered for future clinical use as a therapeutic agent to treat CRC.

Thrombomodulin Influences the Survival of Patients with Non-Metastatic Colorectal Cancer through Epithelial-To-Mesenchymal Transition (EMT)

Background

Treatment resistance and metastasis are the major causes of death among patients with colorectal cancer (CRC). Approximately 20% of surgically treated patients ultimately develop metastases during the follow-up period. Currently, the TNM system is the only available prognostic test. Therefore, the identification of new markers for CRC remains important. Thrombomodulin (TM), a glycoprotein, is involved in angiogenesis and has been linked to many malignant diseases. However, the function of TM in CRC remains unclear.

Methods

A total of 170 patients with CRC participated in this study. TM expression was analyzed via immunohistochemistry. Univariate (Kaplan-Meier) analysis was used to analyze patient outcomes, including overall survival (OS) and disease-free survival (DFS). TM expression was manipulated using shRNA or an overexpression system. Transwell migration assays, wound healing migration assays, and the xCELLigence biosensor system were used to detect cell proliferative and migratory capacities.

Results

TM expression in the tumor tissues significantly and positively correlated with the DFS and OS of non-metastatic patients with CRC (ps = 0.036 and 0.0218, respectively). Suppression of TM expression increased the proliferation and migration of DLD-1 cells. TM overexpression reduced the cells’ proliferative and migratory capacities. Cyclooxygenase (COX)-2 expression was up-regulated following TM silencing. Furthermore, the association between the migration of colon cancer cells and the levels of TM and epithelial-to-mesenchymal transition (EMT) markers (fibronectin, vimentin and ezrin) was confirmed in HT29 and DLD-1 cells.

Conclusions

Our study demonstrates that patients with non-metastatic CRC display low TM expression in their tumors and exhibit reduced DFS and OS. The enhanced expression of mesenchymal markers and COX-2 may be involved in the mechanisms that underlie recurrence in patients with cancer displaying low TM expression.

Folate deficiency-triggered redox pathways confer drug resistance in hepatocellular carcinoma

Patients with hepatocellular carcinoma (HCC) are prone to folate deficiency (FD). Here we showed that, in cell line-specific manner, FD caused resistance to FD-induced oxidative stress and multi-drug resistance (MDR). This resistance was due to upregulation of glucose-regulated protein 78 (GRP78) and Survivin. Using siRNA and Epigallocatechin gallate (EGCG), we found that GRP78 and Survivin cooperatively conferred MDR by decreasing FD-induced ROS generation. Our data showed that FD increases GRP78 and Survivin, which serve as ROS inhibitors, causing MDR in HCC. We suggest that folate supplementation may enhance the efficacy of chemotherapy.

Niclosamide suppresses cell migration and invasion in enzalutamide resistant prostate cancer cells via Stat3-AR axis inhibition

PURPOSE

It is known that over expression of IL6 in prostate cancer cells confer enzalutamide resistance and that this may occur through constitutive Stat3 activation. Additionally, recent pre-clinical studies suggested enzalutamide might have the potential adverse effect of inducing metastasis of prostate cancer cells via Stat3 activation. This study is aimed to target Stat3 activation and improve enzalutamide therapy.

EXPERIMENTAL DESIGN

Sensitivity of prostate cancer cells to enzalutamide was tested using cell growth assays and clonogenic assays. Wound healing and invasion assays were performed to determine cell migration and invasion in vitro. Quantitative reverse transcription-PCR, ELISA and Western blotting were performed to detect expression levels of PSA, c-Myc, survivin, Stat3, and AR. ChIP assay was performed to examine recruitment of AR to the PSA promoter.

RESULTS

In the present study, we found niclosamide, a previously identified novel inhibitor of androgen receptor variant (AR-V7), inhibited Stat3 phosphorylation, and expression of downstream target genes. Niclosamide synergistically reversed enzalutamide resistance in prostate cancer cells and combination treatment of niclosamide with enzalutamide significantly induced cell apoptosis and inhibited cell growth, colony formation, cell migration and invasion. Knock down of Stat3 abrogated enzalutamide resistance resulting in reduced recruitment of AR to the PSA promoter in prostate cancer cells expressing IL6. Moreover, niclosamide reversed enzalutamide resistance by down-regulating Stat3 target gene expression Stat3and abrogating recruitment of AR to PSA promoter resulting in PSA inhibition.

CONCLUSIONS

This study demonstrated the IL6-Stat3-AR axis in prostate cancer is one of the crucial mechanisms of enzalutamide resistance. Niclosamide has the potential to target the IL6-Stat3-AR pathway to overcome enzalutamide resistance and inhibit migration and invasion in advanced prostate cancer.

Shikonin suppresses the migratory ability of hepatocellular carcinoma cells

Shikonin is a traditional Oriental medical herb extracted from Lithospermum erythrorhizon. Many studies have shown that shikonin possesses anticancer ability against many different cancers, including hepatocellular carcinoma (HCC). Recently, tumor metastasis has been become an important clinical obstacle. However, the effect of shikonin on metastasis by HCC is unknown. The 50% inhibitory concentration (IC50) of shikonin on HCC cells was determined by an MTT assay and the xCELLigence biosensor system. The migratory ability of HCC cells was detected by a transwell migration assay and the xCELLigence biosensor system. Matrix metalloproteinase-2 and -9 (MMP-2 and -9) expression levels were determined by Western blotting, and the activities of MMP-2 and -9 were determined by gelatin zymography. We found that IC50 values of HepJ5 and Mahlavu cells to shikonin treatment were around 2 μM. Exposure to a low dose of shikonin (0-0.4 μM) did not influence the survival of HCC cells. Interestingly, exposure to a low dose of shikonin inhibited the migratory ability on HepJ5 and Mahlavu cells. To further dissect the mechanism, we found that treatment with a low dose of shikonin reduced the activities and expression levels of MMP-2 and -9, which were correlated with the decreased cell migratory ability of HCC cells. In addition, we found a decrease of vimnetin expression, but no influence on the expression levels of N-cadherin, TWIST, or GRP78. In mechanism dissecting, we found that shikonin treatment may suppress the phosphorylation of AKT and then reduce the NF-κB (NF = nuclear factor) levels, but has no influence on the levels of c-Fos and c-Jun. Furthermore, we also found that shikonin may also reduce the phosphorylation of IκB. We concluded that a low dose of shikonin can suppress the migratory ability of HCC cells through downregulation of expression levels of vimentin and MMP-2 and -9. Our findings suggest that shikonin may be a new compound to prevent the migration of HCC cells.

Epithelial-to-mesenchymal transition: immunohistochemical investigation of related molecules in canine cutaneous epithelial tumours

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is a multistep process, important in tumour invasion and metastasis, characterized by loss of epithelial markers, redistribution of β-catenin and gain of mesenchymal markers. HYPOSTHESIS/OBJECTIVES: Our aim was to investigate the immunohistochemical aberrant expression of cytokeratin, vimentin, survivin and heat shock protein 72 (Hsp72) in canine cutaneous epithelial tumours, to understand the association of expression of these molecules with features of malignancy and their role in the EMT phenotype.

METHODS

Ten canine squamous cell carcinomas (SCCs; one with lymph node metastasis), 30 canine hair follicle tumours (six pilomatricomas, eight infundibular keratinizing acanthomas, six trichoepitheliomas and 10 trichoblastomas) and five normal skin samples were investigated by immunohistochemistry using specific anti-vimentin, -cytokeratin, -survivin and -Hsp72 antibodies. A semi-quantitative method was used to analyse the results, as follows: 0 to <5%; ≥ 5 to <10%; ≥ 10 to <25%; and ≥ 25% of positive cells. Immunofluorescence was performed to investigate survivin-vimentin and survivin-Hsp72 colocalization in selected SCCs. Results - In malignant hair follicle tumours and SCCs, a reduced intensity of cytokeratin and increased survivin and Hsp72 expression were observed. In SCCs, loss of cytokeratin expression and vimentin immunolabelling, suggestive of the EMT phenotype, were evident in <5% of neoplastic cells in the front of tumour invasion. In the same areas, strong nuclear survivin and cytoplasmic Hsp72 staining was evident, often colocalizing. Only a few neoplastic cells in the front of tumour invasion showed vimentin-survivin colocalization.

CONCLUSIONS AND CLINICAL IMPORTANCE

A possible simultaneous involvement of survivin and Hsp72 in tumour invasion and the multistep process of EMT of cutaneous epithelial tumours of dogs is suggested.

Role of EMT in gastrointestinal tract tumors

Epithelial-mesenchymal transition (EMT) refers to the process by which cells transit from epithelial phenotype to mesenchymal phenotype. EMT is important for embryonic development, wound healing, and invasion of carcinomas. The molecular mechanisms of EMT are a hot topic of research in invasion and migration of malignant tumors, especially digestive carcinomas. Since malignant epithelial tumors account for a large proportion of tumors and are associated with very poor outcome and prognosis, exploration of the process of epithelial cell migration and invasion is of great significance for the prevention and treatment of tumors. The investigation of EMT provides a basis for understanding the pathogenesis of tumors and their prognosis and resistance to antitumor drugs. This review focuses on the molecular mechanisms and role of EMT in gastrointestinal tract tumors.

Survivin-mediated therapeutic efficacy of gemcitabine through glucose-regulated protein 78 in hepatocellular carcinoma

BACKGROUND

Survivin is an antiapoptotic molecule that is widely expressed in cancers, including hepatocellular carcinoma (HCC). Survivin has become a general therapeutic target for cancers because of its selective overexpression in a majority of tumors. However, little is known regarding the effect of survivin expression in combination with gemcitabine on HCC.

METHODS

We generated survivin knockdown cells (survivin-KD) via a short interfering RNA (siRNA) technique. The antiproliferation effects of gemcitabine were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, TUNEL (terminal deoxynucleotidyl transferase dUTP nick-end labeling) assay, and cell cycle evaluation.

RESULTS

According to the MTT assay, we found that survivin-KD cells were more sensitive than parental cells and scrambled control cells to gemcitabine treatment. The apoptotic cell population increased in survivin-KD cells that were treated with gemcitabine in comparison to scrambled control cells, as observed by the cell cycle distribution and TUNEL assays. We found that survivin knockdown resulted in a reduction of glucose-regulated protein 78 (GRP78), which may be responsible for the observed increased survivin-KD cell sensitivity to gemcitabine.

CONCLUSIONS

We conclude that survivin knockdown may contribute to a therapeutic effect of gemcitabine through GRP78 on HCC cells.

NNK enhances cell migration through α7-nicotinic acetylcholine receptor accompanied by increased of fibronectin expression in gastric cancer

BACKGROUND

In this study, we intended to dissect the mechanism of 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-enhanced migration of gastric cancer. Smoking has been defined as a risk factor for gastric cancer. Tobacco-specific carcinogen, NNK, was reported to enhance cancer progression in gastric cancer. Currently, metastasis is the major issue for clinical cancer therapy, but the influence of NNK on the migration of gastric cancer remains to be determined.

METHODS

The expression of nicotinic receptor in gastric cancer cells was identified by real-time polymerase chain reaction and Western blotting. The influence of NNK on migration of gastric cancer cells was evaluated by the transwell migration assay system. Receptor-mediated migration was studied by both inhibitor and small interfering RNA.

RESULTS

Alpha7 nicotinic acetylcholine receptor, alpha7-nicotinic acetylcholine receptor (nAChR), was identified higher than alpha9-nAChR in gastric cancer cell lines, AGS cells. NNK enhanced significantly gastric cancer cell migration in transwell assay. We used inhibitor and siRNA to demonstrate that alpha7-nAChR mediated NNK-enhanced gastric cancer cell migration and upregulation of fibronectin were involved in NNK-enhanced migration of gastric cancer cells. Finally, we found that silenced fibronectin expression level inhibited the migratory ability in AGS cells.

CONCLUSIONS

NNK enhanced gastric cancer metastasis through alpha7-nAChR and fibronectin-one of the hallmarks of epithelial mesenchymal transition.