Interaction mechanisms between autophagy and ferroptosis: Potential role in colorectal cancer.

Colorectal cancer (CRC) is a common malignancy that has the second highest incidence and mortality rate. Although there are many personalized treatment options for CRC, the therapeutic effects are ultimately limited by drug resistance. Studies have aimed to block the initiation and progression of CRC by inducing cell death to overcome this obstacle. Substantial evidence has indicated that both autophagy and ferroptosis play important regulatory roles in CRC. Autophagy, a lysosome-dependent process by which cellular proteins and organelles are degraded, is the basic mechanism for maintaining cell homeostasis. The duality and complexity of autophagy in cancer therapy is a hot topic of discussion. Ferroptosis, a regulated cell death pathway, is associated with iron accumulation-induced lipid peroxidation. The activation of ferroptosis can suppress CRC proliferation, invasion and drug resistance. Furthermore, recent studies have suggested an interaction between autophagy and ferroptosis. Autophagy can selectively degrade certain cellular contents to provide raw materials for ferroptosis, ultimately achieving antitumor and anti-drug resistance. Therefore, exploring the interaction between autophagy and ferroptosis could reveal novel ideas for the treatment of CRC. In this review, we describe the mechanisms of autophagy and ferroptosis, focusing on their roles in CRC and the crosstalk between them.

Cavernous hemangioma of the ileum in a young man: A case report and review of literature.

BACKGROUND: Small intestinal cavernous hemangioma is a rare disease, especially in the ileum. It is difficult to accurately diagnose due to its hidden location and nonspecific clinical symptoms. Here, we reported a case of ileal cavernous hemangioma with chronic hemorrhage in a 20-year-old man and review the literature to gain a better understanding of this disease. CASE SUMMARY: The patient complained of intermittent melena and hematochezia for > 3 mo. The lowest hemoglobin level revealed by laboratory testing was 3.4 g/dL (normal range: 12-16 g/dL). However, the gastroscopy, colonoscopy and peroral double-balloon enteroscopy (DBE) showed no signs of bleeding. The transanal DBE detected a lesion at about 340 cm proximal to the ileocecal valve. Thus, we performed an exploratory laparoscopy and the lesion was resected. After the operation, the patient had no melena. Finally, the pathological examination identified the neoplasm as an ileal cavernous hemangioma, thereby resulting in gastrointestinal hemorrhage. CONCLUSION: This report might improve the diagnosis and treatment of ileal cavernous hemangioma.

Application Value and Research Progress of Human Microbiome in Sexual Assault Cases.

In recent years, sexual assault cases have been on the rise, seriously infringing the legitimate rights and interests of women and children, causing widespread concern in society. DNA evidence has become the key evidence to prove the facts in sexual assault cases, but lack of DNA evidence or only DNA evidence in some sexual assault cases leads to unclear facts and insufficient evidence. With the emergence of high-throughput sequencing technology and the development of bioinformatics and artificial intelligence, new progress has been made in the study of human microbiome. Researchers have begun to use human microbiome for difficult sexual assault cases indentification. This paper reviews the characteristics of human microbiome, and its application value in the inferences of the body fluid stain origin, the sexual assault method, the crime time, etc. In addition, the challenges faced by the application of the human microbiome in practical case handling, the solutions and future development potential are analyzed and prospected.

SphK1-driven autophagy potentiates focal adhesion paxillin-mediated metastasis in colorectal cancer.

Invasion and metastasis are the main causes of colorectal cancer (CRC)-related death. Accumulating evidence suggested that sphingosine kinase 1 (SphK1) promoted the metastasis of CRC and autophagy played an important role in SphK1 promoting the metastasis of malignancy. However, the mechanism by which SphK1-driven autophagy promotes invasion and metastasis in CRC remains to be clarified. In the present study, immunohistochemical detection showed the expression of SphK1 and paxillin was higher in human CRC tissues than those of normal colorectal mucosal tissues, they were both associated with TNM staging, lymphatic, and distance metastasis. In addition, study of in situ tumor transplantation model in nude mice showed that the suppression of SphK1 inhibited the growth of colonic orthotopic implantation tumors and the expression of paxillin, p-paxillin, LC3 in the tumor. So, SphK1 may promote CRC metastasis via inducing the expression of paxillin expression and its phosphorylation, in vivo. Furthermore, results of CCK8 assay, transwell and wound healing assays showed that SphK1 promoted the viability, invasion, and metastasis of CRC cells. Transmission electron microscopy detection showed that SphK1 is the key factor in autophagy induction in CRC cells. Moreover, western blot examination indicated that the expression of LC3Ⅱ/Ⅰ, paxillin, p-paxillin, MMP-2, and vimentin was enhanced in SphK1-overexpressed CRC cells and suppressed in SphK1 knockdown CRC cells, meanwhile, the expression of E-cadherin was suppressed in SphK1-overexpressed CRC cells and enhanced in SphK1 knockdown CRC cells. Suppression of autophagy by 3MA reversed the expression of paxillin and its phosphorylation in SphK1-overexpressed CRC cells, indicated that SphK1-driven autophagy induced the expression of paxillin and its phosphorylation in CRC cells. Together, these findings reveal that SphK1-driven autophagy may promote the invasion and metastasis of CRC via promoting the expression of focal adhesion paxillin and its phosphorylation.

Association of tricellulin expression with poor colorectal cancer prognosis and metastasis.

Tricellulin is a tight­junction transmembrane protein that regulates cell­cell interactions. Altered tricellulin expression could promote tumor cell invasions and metastasis in human cancers. The present study assessed tricellulin expression in colorectal cancer tissues for any association with clinicopathological features of colorectal cancer patients and then investigated the underlying molecular events using quantitative proteomic analysis and in vitro experiments. Tissue samples from 98 colorectal cancer patients and 15 volunteers were collected for immunohistochemistry. Colorectal cell lines were used to overexpress or knockdown tricellulin expression in various assays. The data revealed that upregulated tricellulin expression was associated with lymph node and distant metastases and poor prognosis, while tricellulin overexpression promoted colorectal cancer cell migration and invasion in vitro. In contrast, tricellulin knockdown had positive effects on the tumor cells. Furthermore, TMT­LC­MS/MS and bioinformatics analyses revealed that tricellulin was involved in EMT and reduction of apoptosis through the NF­κB signaling pathway. These findings highlight for the first time the significance of tricellulin in colorectal cancer development and progression. Further study may validate tricellulin as a novel biomarker and target for colorectal cancer.

Microbial Profiles and Risk Factors of Preexisting Biliary Infection in Patients with Therapeutic Endoscopy.

BACKGROUND: The bile infection may already exist before the administration of an interventional procedure, despite no clinical manifestations of cholangitis detected. Blood cultures remained negative even in more than half of the febrile cases with cholangitis. Risk factors associated with bacterial growth in bile before the intervention are not well defined. To establish the bacterial profiles isolated from the bile samples and to identify risk factors for bacterial colonization in the bile system. METHODS: Individuals who underwent endoscopic retrograde cholangiopancreatography (ERCP) interventions were enrolled. Bile samples were aspirated and were immediately transferred into a sterile tube for storage. RESULTS: Positive bile cultures were detected in 363 (38.0%) of 956 patients, including 322 benign diseases and 41 malignances. Of 363 positive cases, 351 (96.7%) were monoinfection and 12 (3.3%) multi-infection. Escherichia coli were the most common Gram-negative bacteria (210, 56.0%), followed by Klebsiella pneumoniae (45, 12.0%). Enterococcus faecalis represented the most common Gram-positive microorganism (19, 5.07%), while Candida albicans (11, 2.93%) were the dominant fungi. Klebsiella pneumoniae were more frequently detected in malignant diseases (P = 0.046). Age, previous ERCP history or OLT history, and CBD diameter were independent risk factors for positive cultures (P < 0.05) while preoperative jaundice drug therapy was the protective factor for bile infection (P < 0.05). CONCLUSION: Monomicrobial infection was dominant among all infections, and Klebsiella pneumoniae strains were more frequently isolated from patients with malignant diseases. To effectively manage patients who are at a high risk for bile infection, a detailed diagnosis and treatment plan for each case should be prepared.

Sphingosine kinase 1 promotes the metastasis of colorectal cancer by inducing the epithelial­mesenchymal transition mediated by the FAK/AKT/MMPs axis.

It was demonstrated that Sphingosine kinase 1 (SphK1) promotes tumor progression and confers the malignancy phenotype of colorectal cancer by activating the focal adhesion kinase (FAK) pathway. However, further clarification is required to determine if SphK1 promotes the metastasis of colorectal cancer by inducing epithelial­mesenchymal transition (EMT), and its mechanisms have not been fully elucidated. Immunohistochemistry staining was used to detect protein expression in normal colonic mucosa tissues and colorectal cancer tissues. Cells were transfected to overexpress SphK1, downregulate SphK1 or downregulate FAK. An MTT assay was used to detect the drug toxicity to cells. Transwell and wound healing assays were used to detect cell migration ability. Reverse transcription­polymerase chain reaction and western blot analysis were used to detect the expression of mRNA and protein, respectively. Scanning electron microscopy was used to observe the microvilli and pseudopodia of the cells. The analysis of protein expression in 114 human colorectal cancer tissues demonstrated that the expressions of SphK1, FAK, phosphorylated (p)­FAK, E­cadherin and vimentin were associated with the metastasis of colorectal cancer. Furthermore, the patients with colorectal cancer with SphK1­positive cancer demonstrated poorer prognosis compared with SphK1­negative cancer. FAK knockdown and SphK1 knockdown of human colon cancer RKO cells inhibited the EMT and migrational potency, along with the expression of p­FAK, p­protein kinase B (AKT) and matrix metalloproteinase (MMP)2/9. In contrast, SphK1 overexpression promoted EMT, migrational potency, and the expression of p­FAK, p­AKT and MMP2/9 in HT29 cells. Additionally, the EMT and migrational potency of SphK1­overexpressing HT29 cells was suppressed by a FAK inhibitor, and the expression of p­FAK, p­AKT and MMP2/9 was suppressed by blocking the FAK pathway. In conclusion, SphK1 promoted the migration and metastasis of colon cancer by inducing EMT mediated by the FAK/AKT/MMPs axis.

NIK­ and IKKß­binding protein contributes to gastric cancer chemoresistance by promoting epithelial­mesenchymal transition through the NF­κB signaling pathway.

Systematic chemotherapy is indispensable for gastric cancer patients with advanced stage disease, but the occurrence of chemoresistance drastically limits treatment effectiveness. There is a tremendous need for identifying the underlying mechanism of chemoresistance. NIK­ and IKKß­binding protein (NIBP) (also known as TRAPPC9, trafficking protein particle complex 9) is a regulator of the cytokine­induced NF­κB signaling pathway which has been proven to play pivotal roles in the progression of various malignancies. Nevertheless, it is still ambiguous whether NIBP is involved in the chemoresistance of gastric cancer. The aim of the present study was to investigate the effect of NIBP on chemotherapy resistance of gastric cancer (GC) and to research the mechanisms of Ginkgo biloba extract 761 (EGb 761®) on reversing chemoresistence which has been confirmed in our previous study. In the present study, the results of immumohistochemisty revealed that the positive staining rates of NIBP, NF­κB p65 and NF­κB p­p65 in gastric cancer tissues were obviously higher than those in normal tissues. Furthermore, a close correlation was found to exist between the expression of NIBP and NF­κB p65 (p­p65) in gastric cancer tissues. Moreover, the overexpression of NIBP was closely related to tumor differentiation, depth of invasion, clinical stage and lymphatic metastasis in gastric cancer. Western blot analysis, real­time PCR, MTT assay and flow cytometric analysis were performed and the results demonstrated that compared with the gastric cancer SGC­7901 cells, the expression of NIBP, NF­κB p65, NF­κB p­p65 and mesenchymal marker vimentin were significantly increased in gastric cancer multidrug­resistant SGC­7901/CDDP cells, and the epithelial cell marker ZO­1 was significantly decreased. Meanwhile, it was found that SGC­7901/CDDP cells were accompanied by spindle­like mesenchymal appearance and upregulation of stem cell marker CD133 which has been verified to be an upstream regulatory gene of epithelial­mesenchymal transition (EMT). Further research confirmed that downregulation of NIBP by Ginkgo biloba extract (EGb) 761 EGb 761 suppressed the cis­diamminedichloroplatinum(II) (CDDP)­induced NF­κB signaling pathway, EMT and the expression of CD133 in SGC­7901 and SGC­7901/CDDP cells. Altogether, these data indicate that the NIBP­regulated NF­κB signaling pathway plays a pivotal role in the chemoresistance of gastric cancer by promoting CD133­induced EMT.

SphK1 modulates cell migration and EMT-related marker expression by regulating the expression of p-FAK in colorectal cancer cells.

Sphingosine kinase 1 (SphK1) plays an important role in colorectal carcinoma metastasis. However, whether SphK1 modulates epithelial-mesenchymal transition (EMT)-related marker expression and the underlying mechanisms remain unclear. In this study, in order to clarify this issue, we used various colorectal cancer (CRC) cell lines, Caco2, HT29, RKO and HCT116. Each of the cell lines was divided into 3 groups as follows: the control group, SKI-Ⅱ (SphK1 inhibitor) group and PF-562271 [focal adhesion kinase (FAK) inhibitor] group. The migratory ability of the cells was examined by Transwell chamber assay. The mRNA and protein expression levels of SphK1, FAK (p-FAK), Slug, vimentin, N-cadherin and E-cadherin were detected by PCR and western blot analysis, respectively. The results revealed that the suppression of SphK1 reduced the cell migratory ability, and decreased the expression of Slug, vimentin and N-cadherin; however, the expression of E-cadherin was increased. Moreover, the inhibition of SphK1 reduced the expression of p-FAK. The inhibition of FAK (p-FAK) also decreased the cell migratory ability, and decreased the expression of Slug, vimentin and N-cadherin, whereas the expression of E-cadherin was increased. Thus, our data suggest that SphK1 modulates the expression of EMT-related markers and cell migration by regulating the expression of p-FAK in CRC cells. Thus, SphK1 may play a functional role in mediating the EMT process in CRC.

Double-balloon enteroscopy in diagnosis of small intestinal disease / 中国内镜杂志

Objective To explore the clinical value of double-balloon enterocopy (DBE) in diagnosis of small intestinal diseases. Methods The clinical and endoscope image data of 231 patients with suspected small bowel disease who underwent DBE from January 2008 to May 2016 were analyzed. Result 231 patients received 257 times of DBE examination, 112 of them were performed by oral and 93 by anal route, 26 patients were underwent by both approaches. The detection rate of intestine diseases was 64.9% (150/231), include 33 cases (14.3%) of nonspecific enteritis, 27 cases (11.7%) of crohn's disease, 19 cases (8.2%) of ulcer, 13 cases (5.6%) of intestinal vascular malformation, 12 cases (5.2%) of small intestinal stromal tumor. The lesion detection rate in obscure abdominal pain and obscure gastrointestinal bleeding were 59.6% (62/104) and 67.0% (63/94). In all patients, there were 1 case of small bowel perforation, the remaining patients had no serious complications such as bleeding and perforation. Conclusion The positive detection rate of double-balloon enteroscopy examination is high, and the double-balloon enteroscopy examination is relatively safe. So, double-balloon enterscopy examination has high diagnostic value for detecting small intestine diseases.

Double-balloon enteroscopy in diagnosis of small intestinal disease / 中国内镜杂志

Objective To explore the clinical value of double-balloon enterocopy (DBE) in diagnosis of small intestinal diseases. Methods The clinical and endoscope image data of 231 patients with suspected small bowel disease who underwent DBE from January 2008 to May 2016 were analyzed. Result 231 patients received 257 times of DBE examination, 112 of them were performed by oral and 93 by anal route, 26 patients were underwent by both approaches. The detection rate of intestine diseases was 64.9% (150/231), include 33 cases (14.3%) of nonspecific enteritis, 27 cases (11.7%) of crohn's disease, 19 cases (8.2%) of ulcer, 13 cases (5.6%) of intestinal vascular malformation, 12 cases (5.2%) of small intestinal stromal tumor. The lesion detection rate in obscure abdominal pain and obscure gastrointestinal bleeding were 59.6% (62/104) and 67.0% (63/94). In all patients, there were 1 case of small bowel perforation, the remaining patients had no serious complications such as bleeding and perforation. Conclusion The positive detection rate of double-balloon enteroscopy examination is high, and the double-balloon enteroscopy examination is relatively safe. So, double-balloon enterscopy examination has high diagnostic value for detecting small intestine diseases.

NIBP impacts on the expression of E-cadherin, CD44 and vimentin in colon cancer via the NF-κB pathway.

NIBP, a novel nuclear factor-κB (NF-κB)-inducing kinase (NIK) and IκB kinase ß (IKKß) binding protein, directly interacts with NIK and IKKß, and acts as the 'bridge' of the NF­κB classical and alternative signaling pathways. However, its influence on epithelial­mesenchymal transition markers in colon cancer remains to be fully elucidated. The aim of the present study was to investigate the roles of NIBP impacting on the expression of E­cadherin, CD44 and vimentin. In the present study, the associations between NIBP and E­cadherin, CD44 and vimentin in clinical samples were analyzed by making pairwise comparisons between normal colon tissue, non­metastatic colon cancer tissue and metastatic colon cancer tissue. In in vitro experiments, after changing the expression of NIBP in cells, the protein expression levels of CD44, vimentin, E­cadherin were analyzed by western blot analysis. The results revealed that the protein expression levels of NIBP, CD44 and vimentin were markedly increased, and E­cadherin was markedly decreased, in metastatic colon cancer tissue compared with normal colon tissue and non­metastatic colon cancer tissue. Upregulation of NIBP expression decreased the levels of E­cadherin, whereas the downregulation of NIBP increased E­cadherin levels, while no significant differences were observed in the levels of CD44 and vimentin. In addition, cells that were treated with the NF­κB inhibitor, pyrrolidine dithiocarbamate (PDTC), also tended to exhibit increased levels of CD44 and vimentin expression in the NIBP upregulated expression group (29­NIBP group) compared with the mock group, whereas the expression levels of E­cadherin, CD44 and vimentin were similar in the NIBP downregulated expression group (116­NIBPmir group) and the HCT116 blank control group (116­mock group) on treatment of the cells with tumor necrosis factor­α. These findings indicated that NIBP, E­cadherin, CD44 and vimentin are possibly associated with metastasis in colon cancer. When the NF­κB pathway is not subjected to any interventions, NIBP may predominantly regulate the NF­κB classical pathway, rather than the alternative pathway. When the classical pathway was completely inhibited, NIBP was able to activate the NF­κB alternative pathway. NIBP is therefore necessary for the interaction between the NF­κB classical and alternative pathways. In conclusion, NIBP impacts on the expression levels of E­cadherin, CD44 and vimentin via the NF­κB classical and alternative pathways. Therapeutic regimens for patients with colorectal cancer may comprise NIBP inhibitors in the future.

Ginkgo biloba extract enhances chemotherapy sensitivity and reverses chemoresistance through suppression of the KSR1-mediated ERK1/2 pathway in gastric cancer cells.

Kinase suppressor of Ras 1 (KSR1) is a scaffold protein that modulates the activation of the oncogenic mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathway. Ginkgo biloba extract (EGb) 761 has been demonstrated to possess antitumor activity that may be related to the KSR1-mediated ERK signaling pathway. However, the roles and its underlying mechanism in gastric cancer are unclear. In the present study, 62 gastric cancer and matched normal tissues were exploited for immunohistochemistry and real-time fluorescent quantitative PCR detection. Results of the immunohistochemistry showed that the expression of ERK1/2 and p-ERK1/2 was correlated to the expression of KSR1 and p-KSR1 in the gastric cancer tissues, and the overexpression of KSR1, p-KSR1, ERK1/2 and p-ERK1/2 was significantly associated with histological grade, TNM stage, lymph node and distant metastasis. Compared with the normal tissues, the relative mRNA copy values of KSR1, ERK1 and ERK2 in the cancer tissues were 2.43 ± 0.49, 2.10 ± 0.44 and 3.65 ± 0.94. In addition, the expression of KSR1, p-KSR1, ERK1/2 and p-ERK1/2 in human gastric cancer multidrug resistant SGC-7901/CDDP cells was higher than that in the SGC-7901 cells as detected by the methods of immunocytochemistry and western blot analysis. EGb 761 not only suppressed expression of these proteins induced by cisplatin (CDDP) and etoposide in SGC-7901 cells, but also inhibited expression of these proteins in the SGC-7901/CDDP cells. Meanwhile, the proliferation-suppressing and apoptosis-inducing capacities of CDDP and etoposide were enhanced following combined treatment with EGb 761. Moreover, EGb 761 reduced the malondialdehyde (MDA) content and elevated the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the tumor cells. These results confirmed that activation of the KSR1-mediated ERK1/2 signaling pathway may contribute to tumorigenesis, metastasis and chemoresistance of human gastric cancer. EGb 761 enhanced the chemotherapy sensitivity and reversed the chemoresistance through suppression of the KSR1-mediated ERK1/2 pathway in gastric cancer cells, and the underlying mechanism may be related to its antioxidative activity.

[Sphingosine kinase 1 enhances the proliferation and invasion of human colon cancer LoVo cells through up-regulating FAK pathway and the expression of ICAM-1 and VCAM-1].

OBJECTIVE: To investigate the effects of sphingosine kinase 1 (SphK1) on the proliferation, migration and invasion of human colon cancer LoVo cells, and to explore the related mechanisms. METHODS: Human colon cancer LoVo cells were divided into three groups: phorbol 12-myristate 13-acetate (PMA) was used to induce the activation of SphK1 in the PMA group, N,N-dimethylsphingosine (DMS) used to suppress the activity of SphK1 in DMS group, and the cells treated with equal amount of 0.9 % NaCl instead of drugs served as the control group. The activity of SphK1 was assayed by autoradiography, the cell proliferation was assessed by MTT assay, cell migration and invasion were examined by Boyden chamber assay, concentrations of sICAM-1 and sVCAM-1 were assayed by ELISA, and RT-PCR and Western blot were used to evaluate the mRNA and protein expression in the cells. RESULTS: The activity of SphK1 was efficiently induced by PMA and significantly suppressed by DMS. PMA induced cell proliferation in a time- and dose-dependent manner. On the contrast, DMS suppressed cell proliferation in a time- and dose-dependent manner. After treating with PMA, the number of migrating and invasing cells were increased to 143.36 ± 8.73 and 118.46 ± 6.25, significantly higher than those of the control group (75.48 ± 6.12 and 64.19 ± 5.36). After treating with DMS, the number of migrating and invasing cells were decreased to 38.57 ± 3.24 and 32.48 ± 4.27, significantly lower than those of the control group (P < 0.01). The relative expression levels of FAK, ICAM-1 and VCAM-1 mRNA in the PMA group were 0.82 ± 0.06, 0.74 ± 0.05 and 0.89 ± 0.09, and those in the DMS group were 0.23 ± 0.02, 0.26 ± 0.03 and 0.37 ± 0.04, with significant differences between the PMA, DMS and control groups (P < 0.01). Compared with the control group, the relative expression levels of FAK and p-FAK proteins in the PMA group (0.52 ± 0.06 and 0.51 ± 0.06) were significantly elevated, and those of the DMS group (0.20 ± 0.03 and 0.09 ± 0.02) were significantly decreased. In addition, the concentrations of sICAM-1 and sVCAM-1 were significantly elevated with the activation of SphK1. On the contrary, those of the DMS group were significantly reduced with the suppression of SphK1 (Both P < 0.01). CONCLUSIONS: SphK1 may enhance the proliferation, migration and invasion of colon cancer LoVo cells through activating FAK pathway and up-regulating the expression of ICAM-1 and VCAM-1.

Sphingosine kinase 1 promotes tumor progression and confers malignancy phenotypes of colon cancer by regulating the focal adhesion kinase pathway and adhesion molecules.

Studies suggest a tumor-promoting function of sphingosine kinase 1 (SphK1) in some types of human tumors, however, its effect on colon cancer is still unclear. The aims of this study were to investigate the roles of SphK1 in the progression and tumor cell phenotypic changes in colon cancer. Moreover, the focal adhesion kinase (FAK) pathway and the expression of intercellular adhesion molecule­1 (ICAM­1) and vascular cell adhesion molecule­1 (VCAM­1) were detected to explore the mechanisms of SphK1 action. In this study, the expression of SphK1, FAK and phospho-FAK (p-FAK) was analyzed in 66 surgical specimens of primary colon cancer and matched adjacent normal tissues by immunohistochemistry and western blotting. In addition, N,N-dimethylsphingosine (DMS), SphK1 DNA and shRNA transfection were used to regulate the expression and activity of SphK1 in the LOVO colon cancer cell line. Tumor cell phenotypic changes were analyzed by cell viability, invasion and apoptosis assays. Results showed that the expression of SphK1, FAK and p-FAK in colon cancer tissues were significantly stronger compared to those in matched normal tissues. There was a close correlation between the expression of SphK1 and FAK or p-FAK and the co-expression of SphK1, FAK and p-FAK significantly associated with histological grade, Dukes' stage, lymph node metastasis and distant metastasis. Overexpression of SphK1 after DNA transfection enhanced tumor cell viability and invasiveness, but suppressed cell apoptosis. In contrast, suppression of SphK1 by DMS and shRNA reduced tumor cell viability and invasiveness, but promoted cell apoptosis. The expression of FAK, p-FAK, ICAM-1 and VCAM-1 in LOVO cells were increased with the overexpression of SphK1 but decreased with the suppression of SphK1. These findings indicate that SphK1 regulates tumor cell proliferation, apoptosis and invasion, which ultimately contributes to tumor progression and malignancy phenotype in colon cancer. FAK pathway, ICAM-1 and VCAM-1 may play critical roles in this SphK1­mediated effect.

[The expression and clinical significance of SphK1 and nuclear factor-κB p65 in human colon carcinoma].

OBJECTIVE: To investigate the expression of sphingosine kinase 1 (SphK1) and NF-κB in colon carcinoma tissues and their correlation with clinicopathologic features. METHODS: Sixty-six paraffin-embedded colon carcinoma samples and 66 fresh colon carcinoma samples were tested using immunohistochemistry, RT-PCR and Western blot, respectively. RESULTS: In 66 fresh colon carcinoma samples, the positive rate of SphK1 and NF-κB mRNA expression were 84.85%(56/66) and 74.24% (49/66), while the positive rate of SphK1 and NF-κB protein detected by Western blot were 78.79% (52/66) and 69.70% (46/66). The positive rates were higher than those in the adjacent tissues [mRNA: 63.64% (42/66), 48.49% (32/66); protein: 57.58% (38/66), 45.45% (30/66)] and the normal mucosa [mRNA: 42.42% (28/66), 25.76% (17/66); protein: 36.36% (24/66), 24.24% (16/66)], with statistical significances (all P values < 0.05). The mean expressive levels of SphK1 and NF-κB mRNA and protein in colon carcinoma were both significantly higher than those in the adjacent tissues and the normal mucosa (mRNA: 0.55 ± 0.06 vs 0.35 ± 0.05 vs 0.25 ± 0.05, 0.75 ± 0.06 vs 0.43 ± 0.05 vs 0.30 ± 0.04; protein: 0.77 ± 0.05 vs 0.38 ± 0.06 vs 0.12 ± 0.03, 0.45 ± 0.08 vs 0.23 ± 0.05 vs 0.13 ± 0.03; all P values < 0.05). There was a close correlation between SphK1 and NF-κB expression levels (r = 0.459, P = 0.036). The results of immunohistochemistry were similar to those of RT-PCR and Western blot. Overexpression of SphK1 and NF-κB in colon carcinoma was related with depth of invasion, distant and lymph node metastasis and Dukes' stages (all P values < 0.05). The expression of SphK1 was also related with differentiation (P < 0.05). CONCLUSIONS: Overexpression of SphK1 and NF-κB may be involved in the pathogenesis and progression of colon carcinoma. Moreover, SphK1 and NF-κB may be correlated with the invasion and metastasis of colon carcinoma.

Sphingosine kinase 1 enhances colon cancer cell proliferation and invasion by upregulating the production of MMP-2/9 and uPA via MAPK pathways.

PURPOSE: Sphingosine kinase (SphK) 1 is an oncogenic enzyme promoting transformation, proliferation, and survival of a number of human tumor cells. However, its effect on colon cancer cell behavior has not been fully clarified. METHODS: SphK1 plasmid or SphK1 shRNA transfection and N,N-dimethylsphingosine (DMS) was used to regulate the expression and activity of SphK1 in colon cancer line LOVO. Cell proliferation, apoptosis, invasion, and protein expression were detected by MTT, flow cytometry, transwell chambers model, and western blot. The levels of metalloproteinases-2/9 (MMP-2/9) and urokinase plasminogen activator (uPA) were detected by ELISA. RESULTS: Overexpression of SphK1 after plasmid transfection markedly enhanced LOVO cell viability and invasiveness and reduced cell apoptosis. In contrast, inhibition of SphK1 by DMS and shRNA significantly suppressed cell viability and invasiveness but promoted cell apoptosis. SphK1 increased the constitutive expression of extracellular signal-regulated kinase1/2 (ERK1/2) but reduced the constitutive expression of p38 mitogen-activated protein kinase (MAPK). Blocking ERK1/2 pathway inhibited the biological effects induced by overexpression of SphK1. Blocking p38 MAPK pathway reversed the effects of DMS and SphK1 shRNA. Moreover, SphK1 was required for the production of MMP-2/9 and uPA in tumor cells, which was suppressed by ERK1/2 inhibitor U0126, but enhanced by the p38 MAPK inhibitor SB203580. CONCLUSIONS: SphK1 enhances colon cancer cell proliferation and invasiveness, meanwhile suppressing cell apoptosis. SphK1 promoting the secretion of MMP-2/9 and uPA via activation of ERK1/2 and suppression of p38 MAPK pathways maybe the molecular mechanisms for its regulation of the malignant behavior of colon cancer cell.

[Effect of sphingosine kinase 1 on the apoptosis, migration and invasion of colon cancer HT-29 cells and its molecular mechanisms].

OBJECTIVE: To investigate the effect of sphingosine kinase 1 (SphK1) on the proliferation, apoptosis, migration and invasion of colon cancer TH-29 cells and to explore its molecular mechanisms. METHODS: Phorbol 12-myristate 13-acetate (PMA) was used to induce the activity of SphK1 and N, N-dimethylsphingosine (DMS) was used to suppress the activity of SphK1. Cell prolieration and apoptosis were detected by MTT assay and flow cytometry, respectively. The migration and invasion capabilities of the cells were assessed in Transwell chambers. The activity of SphK1 was assayed by autoradiography. Western blot was used to evaluate the protein expression of SphK1, p38, phosphorylated p38 (p-p38) and SAPK/JNK. RESULTS: PMA and DMS were able to induce and suppress the activity and protein expression of SphK1 in a time-dependent manner, respectively. PMA enhanced and DMS suppressed the cell viability in a time- and dose-dependent manner. Being treated with 100 nmol/L PMA or 50 µmol/L DMS for 0, 6, 12, 24 h, the cell apoptosis rates of PMA group were (9.35 ± 0.84)%, (7.61 ± 0.48)%, (5.53 ± 0.76)% and (0.56 ± 0.33)%, contrastly, that of DMS group were (9.18 ± 0.94)%, (12.06 ± 1.41)%, (19.80 ± 2.36)% and (31.85 ± 3.60)%, respectively. Compared with the control group, the cell migration and invasion capabilities of the PMA group were significantly enhanced, and that of the DMS group were significantly suppressed. The migration cell number of control, PMA and DMS groups were 68.75 ± 6.15, 109.33 ± 11.63 and 10.83 ± 2.48, the invasion cell number of control, PMA and DMS groups were 55.42 ± 4.50, 90.58 ± 7.06 and 9.58 ± 2.39, respectively. With the elevating activity and expression of SphK1, the protein expressions of p38, p-p38 and SAPK/JNK were strikingly suppressed. On the contrary, after treating with DMS the protein expressions of p38, p-p38 and SAPK/JNK were enhanced. CONCLUSIONS: SphK1 potently enhances the prolieration, migration and invasion of colon cancer HT-29 cells, meanwhile suppresses the cell apoptosis. The suppressing of the p38 and SAPK/JNK signalling pathways may be one of its molecular mechanisms.

Inhibition of SPHK1 suppresses phorbol 12-myristate 13-acetate-induced metastatic phenotype in colorectal cancer HT-29 cells.

Expression of sphingosine kinase 1 (SPHK1) plays a role in colorectal cancer progression. This study aimed to demonstrate the mechanism of human colorectal cancer cell metastatic phenotype through SPHK1 knockdown. Human colorectal cancer HT-29 cells were stimulated by phorbol 12-myristate 13-acetate (PMA) with or without SPHK1 siRNA transfection. Tumor cell phenotypic changes were analyzed by using invasion, motility, cell viability, and apoptosis assays. Gene expressions were assessed using Western blot. PMA induced a metastatic phenotype in colorectal cancer cells, as indicated by cell viability, migration and invasion capacity, and ERK1/2 phosphorylation, whereas SPHK1 siRNA transfection suppressed the metastatic phenotype of tumor cells and antagonized PMA's effects. SPHK1 knockdown also inhibited secretion of MMP-2 and MMP-9 into the tumor cell conditioned medium. Suppression of SPHK1 expression suppresses the PMA-induced metastatic phenotype via ERK1/2 phosphorylation in human colorectal cancer cells.

Involvement of mitochondrial pathway in NCTD-induced cytotoxicity in human hepG2 cells.

BACKGROUND: Norcantharidin, the demethylated analog of cantharidin derived from a traditional Chinese medicine, Mylabris, has been used in the treatment of anti-cancer effects. However, the detailed mechanisms underlying this process are generally unclear. The aim of this study was to investigate the mechanism of NCTD-induced apoptosis in HepG2 cells. METHODS: The cytotoxicity was measured by MTT assay for cellular viability and by flow cytometry. The mitochondrial membrane potential and reactive oxygen species production was evaluated by flow cytometry analysis. The role of caspase activities were assayed using caspase apoptosis detection kit . Western blot analysis was used to evaluate the level of Cyto-C, Bcl-2, Bax, Bid, caspase 3, -9, -8 and PARP expression RESULTS: After treatment with NCTD, a decrease in the viability of HepG2 cells and increase in apoptosis were observed. NCTD-induced apoptosis was accompanied by an increase in ROS production, loss of mitochondrial membrane potential and release of cytochrome c(cyto-c) from the mitochondria to the cytosol and down-regulation of anti-apoptotic protein Bcl-2 levels with concurrent up-regulation in pro-apoptotic protein Bax levels. However, another pro-apoptotic molecule, Bid, showed no change in such same treatment. NCTD-increased activity of caspase 9,caspase 3 and the subsequent cleavage caspase substrate PARP were also observed. The expression levels of pro-caspase-8 were not changed after NCTD treatment. CONCLUSION: These results indicate that NCTD induced cytotoxicity in HepG2 cells by apoptosis, which is mediated through ROS generation and mitochondrial pathway.