Abstract: Cancer-associated fibroblasts (CAFs) are one of the predominant stromal cells that constitute the tumor microenvironment,and play an essential role in tumor growth, metastasis, chemoresistance and tumor immunity. Autophagy is a cellular process through which cells degrade products in the metabolic process and reuse them to respond to environmental stress. Autophagy is important for tumor initiation, progression and response to therapy, as it connects cellular homeostasis with the extracellular environment that affects immunity and metabolism. This review, by introducing the role of autophagy in CAFs and its regulatory mechanism, summarizes the research progress on studies of autophagy in CAFs and tumor metabolism, progression, metastasis and resistance to therapy.
Abstract: Objective: This study aimed at investigating the epigenetic regulation mechanism of abnormally low expression of SHP-1 gene in esophageal squamous cell carcinoma (ESCC). Methods: A total of 71 cases of ESCC tissues and corresponding para-cancer tissues(2 cm from the edge of the cancer) resected during surgery at the Department of thoracic surgery of Hebei Province, the Fourth Hospital of Hebei Medical University from 2008 to 2011 were collected for this study. The expression level of SHP-1 mRNA and protein was detected in esophageal cancer cell lines (Eca109, Kyse170, Yes-2) before and after 5-Aza-dC or TSA treatment by RT-qPCR and Western blotting methods respectively. The methylation status of CpG sites in promoter region of SHP-1 was analyzed by bisulfite genome sequencing (BGS) in three esophageal cancer cell lines before and after 5-Aza-dC treatment. The methylation status of SHP-1 was studied by methylation-specific polymerase chain reaction (MSP) method in esophageal cancer cell lines, ESCC tissues and para-cancer tissues. The association between the SHP-1 promoter methylation status and clinic pathological parameters were analyzed in ESCC patients. Dual-luciferase reporter assay systems method was applied to detect the impacts of methylation status of CpG island in SHP-1 promoter region on gene transcription activity. For prognostic analysis of SHP-1 methylation, survival curves were constructed using the Kaplan-Meier method and the log-rank. Results: After treated with 5-Aza-dC, the expression level of SHP-1 mRNA and protein was significantly up-regulated in Eca109, Kyse170 and Yes-2 cells, meanwhile the methylation status of SHP-1 was decreased (P<0.05). The expression level of SHP-1 had no obviously change after treated with trichostatin A(TSA). The methylation frequency of promoter in ESCC tumor tissues was significantly higher than that in corresponding para-cancer tissues (P<0.05). When stratified for clinic pathologic characteristics, methylation frequency of SHP-1 was associated with TNM stage, pathological differentiation,and LN metastasis (P<0.05). The mRNA expression level of SHP-1 in the ESCC tissues with SHP-1 methylation was significantly decreased compared to the ESCC tissues with unmethylation of SHP-1 (P<0.05). It was associated with methylation of promoter (P<0.05). The activity of fluorescein reporter vector in methylase treatment group was significantly lower than that in untreated group (P<0.05), indicating that SHP-1expression can be silenced by methylation of SHP-1 promoter. The result of Kaplan-Meier shown that SHP-1 promoter methylation was correlated with ESCC patients’poor survival. Conclusion: The transcriptional activity of SHP-1 can be inhibited with hypermethylated SHP-1 promoter region. The hypermethylated SHP-1 promoter induced the silencing of SHP-1.Therefore, SHP-1 gene may serve as one of prognostic methylation biomarkers for ESCC patients.
Abstract: Objective: To investigate the anti-tumor effect and mechanism of new LL-37 hybrid peptide on breast cancer MCF-7 cells.Methods: Human antimicrobial peptide LL-37 and human neutrophil peptide 1(HNP-1) were screened by using of Antimicrobial Peptides Database (http:// aps.unmc.edu/AP/main.php). The new LL-37 hybrid peptide was synthesized by integrating the active fragments,which were selected by bioinformatics analysis. The breast cancer MCF-7 cells and human normal breast MCF10A cells were treated with the new LL-37 hybrid peptides (0~70 μmol/L). Cell viability was monitored by CCK-8 assay and the affinity of the new LL-37 hybrid peptide with MCF-7 cells was observed using confocal laser scanning microscope (CLSM). The effects of LL-37 and caspase inhibitor on apoptosis and cell cycle of MCF-7 cells were measured by FCM (flow cytometry). Results: The new LL-37 hybrid peptide, as an amphiphilic cationic polypeptide, could selectively inhibit the proliferation of breast cancer MCF-7 cells (P<0.05) with an IC50 of 58.34 μmol/L, but exerted no significant effect on normal breast MCF10A cells. LL-37 peptide had high affinity with MCF-7 cells, which could cause S-stage stagnation and significantly increased early apoptosis (P<0.01); however, the cell cycle block and apoptosis were significantly attenuated after the treatment of caspase inhibitor (P<0.01). Conclusion: The new LL-37 hybrid peptide has anti-tumor activity on breast cancer MCF-7 cells, and could induce MCF-7 cells apoptosis possibly by arresting cell cycle via the caspase-dependent signaling pathway.
Abstract: Objective: To investigate the effect of Beclin1 knockdown on cisplatin resistance in ovarian cancer A2780 cells and its related mechanisms. Methods: The mRNA and protein expressions of Beclin1 in A2780 cells and drug resistant A2780/DDP cells were determined by qPCR and Western blotting. After transfection with Beclin1 siRNA, the sensitivity of A2780/DDP cells to cisplatin was detected by MTT assay; Cell clone formation and apoptosis were detected by the Colony formation assay and Flow cytometry assay, respectively; cell autophagy was monitored by monodansylcadaverin (MDC) staining. Furthermore, the protein levels of cell autophagy related proteins, lysosomal associated membrane protein Lamp-2 and Cathepsin B were detected by Western blotting.Results: The mRNA and protein expression levels of Beclin1 in cisplatin-resistant A2780/DDP cells were significantly higher than those in A2780 cells (all P<0.05). The expression of Beclin1 was significantly increased in A2780 cells after treated with cisplatin (P<0.05). Beclin1 knockdown promoted cisplatin induced apoptosis of A2780/DDP cells (P<0.05), inhibited autophagy and cell colony formation (all P<0.05), and increased cell sensitivity to cisplatin (P<0.05). Meanwhile, Western blotting showed that Beclin1 knockdown increased the protein levels of cleaved-caspase 3 and Cathepsin B in A2780/DDP cells, while down-regulated the protein expressions of Atg3, Atg7, LC3Ⅱ/Ⅰ and Lamp-2 (all P<0.05). Conclusion: Beclin1 knockdown can improve the sensitivity of A2780/DDP cells to cisplatin, and the mechanism may be related to the inhibition of protective autophagy of cells by regulating the expressions of autophagy related proteins, and the regulation of lysosomes, thus further promoting cisplatin-induced apoptosis of drug-resistant cells.
Abstract: Objective: To investigate the role of miR-125a-5p in inducing the gefitinib (Gef)-resistance of non-small cell lung carcinoma (NSCLC) cells and its possible mechanism. Methods: Human NSCLC drug-resistant cell line A549/GR and NSCLC cell line A549 were chosen for this study. miR-125a-5p mimic, miR-125a-5p inhibitor, pcDNA3.1-APAF1 and empty vector pcDNA3.1 were transfected into A549/GR cells. The expression level of miR-125a-5p in cell lines was detected by qPCR. MTT, Transwell and Flow cytometry were used to detect the effects of Gef on proliferation, migration and apoptosis of cell lines, respectively. The targeting relationship between miR-125a-5p and APAF1 (apoptotic peptidase activating factor 1) was verified by Dual-luciferase reporter gene system. In addition, the expression of APAF1 protein in A549/GR cells was detected by Western blotting. The expression levels of caspase-3 and caspase-9 were assessed by colorimetry. Results: Expression level of miR-125a-5p was upregulated significantly in Gefresistant A549/GR cells (P<0.01). And the influences of Gef onA549/GR cells were enhanced by knockdown of miR-125a-5p, including inhibiting cell proliferation and migration (all P<0.05) and inducing apoptosis (P<0.01). Dual luciferase reporter gene assay confirmed that miR-125a-5p targeted APAF1 and negatively regulated its expression. Furthermore, by targetedly downregulating APAF1,miR-125a-5p alleviated the inhibition of proliferation and migration (all P<0.05) and promotion of apoptosis (P<0.05) of A549/GR cells caused by Gef, and attenuated Gef-induced upregulation of apoptosis-related proteins caspase-3 and caspase-9 (all P<0.05).Conclusion: miR-125a-5p promotes Gef-resistance of A549/GR cells, and the underlying mechanisms are promotion of proliferation,migration and inhibition of apoptosis of non-small cell lung cancer cells by targeting APAF1.
Abstract: Objective: To investigate the effect of HMGB1 gene on the growth of human epithelial ovarian cancer xenografts in nude mice, and to lay a foundation for finding new targets for the treatment of ovarian cancer. Methods: Human epithelial ovarian cancer SKOV3 cells in logarithmic growth phase were selected to establish a human epithelial ovarian cancer xenograft model in nude mice.Nude mice with successful model establishment were randomly divided into control group and HMGB1-siRNA group. On the 7th, 9th,11th, 14th, and 16th days after cell inoculation, the same amount of saline and HMGB1-siRNA were respectively injected into two groups of mice under the armpit. After 3 weeks, the nude mice were sacrificed by cervical dislocation, the tumor tissues were separated,and the volume of the tumor was measured. The apoptosis of transplanted tumor cells was detected by Tunnel staining. The expressions of HMGB1, STAT3 and p-STAT3 were detected by Western blotting. The expression of vascular endothelial growth factor A (VEGF-A)and microvascularization were detected by immunohistochemistry. Results: Compared with the control group, the growth of tumor volume slowed down in HMGB1 siRNA group, and on the 21st day, the tumor volume of HMGB1-siRNA group was significantly smaller than that of the control group (P<0.05). HMGB1-siRNA successfully knocked down the expression of HMGB1 mRNA in transplanted tumor tissue. The apoptosis rate of tissue cells in HMGB1-siRNA group was significantly increased ([34±8]% vs [6±2]%, P=0.04), and the expressions of HMGB1 and p-STAT3 were significantly reduced (P<0.05). The expression of VEGF-A and the number of microvessels were significantly lower than those of the control group (both P<0.05). Conclusion: Knockdown of HMGB1 gene reduces the expression of VEGF-A and microvessel formation possibly by inhibiting the HMGB1/STAT3 signaling pathway, thereby promoting the apoptosis of tumor tissues and slowing the growth of xenografts.
Abstract: Immunocyte therapy for tumor has drawn a great attention in recent years due to its significant effect. Immunocytes, including T cell, NK cell and DCs, play a key role in immune responses of anti-tumors and immunotherapy of tumors. Among them, the techique of chimeric antigen receptor (CAR) modified-T cell (CAR-T) and inhibitor therapy which reverses CTLA-4 and PD-1/PD-L1 and so on immune checkpoints of tumor immune suppressive function have respectively achieved exciting results in therapies of blood tumors, melanoma and other solid tumors. How to further improve the efficacy, to increase adaptive tumor diseases and to control immune related adverse reactions of the therapy could become the focus of future research. NK cell will also take advantages of CAR technique and inhibitors of immune checkpoints to further strengthen its role in the tumor therapy. How to enhance the curative effect of DCs as the first therapeutic tumor vaccine approved by FDA based on its confirmed safe and non-toxic side effects could become a hot point. In this paper, problems that need to be solved in the field were further analyzed and prospected with combination of recent advances in the immunocyte-therapy for tumor.
Abstract: Objective: To prepare poly DL lactide poly (PELA) microspheres encapsulating recombinant tissue inhibitors of metalloproteinase 1 (TIMP 1) adenovirus, and to investigate their effects on the proliferation of hepatocellular carcinoma HepG2 cells. Methods:The microsphere was constructed by encapsulating recombinant adenovirus containing TIMP 1 in biodegradable PELA. The diameter of the microsphere, quantity of virus encapsulated, loading rate, and releasing kinetics were measured. HepG2 cells were infected with the microspheres; the infection efficiency was examined by fluorescent microscope; and the ultrastructure was observed by TEM. The expression of TIMP 1 mRNA in HepG2 cells was examined by semi quantitative RT PCR, and the proliferation of HepG2 cells was detected by MTT assay. Results:The microsphere encapsulating recombinant TIMP 1 adenovirus was successfully constructed, with its diameter, entrapment efficiency, and virus loading rate being 1.965, 60.0%, and 10.5×108/mg, respectively. About 60% of the viruses were released within 120 h, and the total releasing time was longer than 240 h. Infection with rAdTIMP 1 PELA microsphere efficiently induced TIMP 1 expression in HepG2 cells, and significantly inhibited the proliferation of HepG2 cells, with the inhibitory rate being 47%. Conclusion:PELA microsphere encapsulating recombinant TIMP 1 adenovirus can markedly inhibit the proliferation of HepG2 cells, which provides an experimental basis for the combining macromolecular chemistry and gene therapy for treatment of hepatocellular carcinoma.