Deciphering the Effects of the PYCR Family on Cell Function, Prognostic Value, Immune Infiltration in ccRCC and Pan-Cancer.

Pyrroline-5-carboxylate reductase (PYCR) is pivotal in converting pyrroline-5-carboxylate (P5C) to proline, the final step in proline synthesis. Three isoforms, PYCR1, PYCR2, and PYCR3, existed and played significant regulatory roles in tumor initiation and progression. In this study, we first assessed the molecular and immune characteristics of PYCRs by a pan-cancer analysis, especially focusing on their prognostic relevance. Then, a kidney renal clear cell carcinoma (KIRC)-specific prognostic model was established, incorporating pathomics features to enhance predictive capabilities. The biological functions and regulatory mechanisms of PYCR1 and PYCR2 were investigated by in vitro experiments in renal cancer cells. The PYCRs' expressions were elevated in diverse tumors, correlating with unfavorable clinical outcomes. PYCRs were enriched in cancer signaling pathways, significantly correlating with immune cell infiltration, tumor mutation burden (TMB), and microsatellite instability (MSI). In KIRC, a prognostic model based on PYCR1 and PYCR2 was independently validated statistically. Leveraging features from H&E-stained images, a pathomics feature model reliably predicted patient prognosis. In vitro experiments demonstrated that PYCR1 and PYCR2 enhanced the proliferation and migration of renal carcinoma cells by activating the mTOR pathway, at least in part. This study underscores PYCRs' pivotal role in various tumors, positioning them as potential prognostic biomarkers and therapeutic targets, particularly in malignancies like KIRC. The findings emphasize the need for a broader exploration of PYCRs' implications in pan-cancer contexts.

Optimal frequency determination for terahertz technology-based detection of colitis-related cancer in mice.

Colorectal cancer is a prevalent malignancy globally, often linked to chronic colitis. Terahertz technology, with its noninvasive and fingerprint spectroscopic properties, holds promise in disease diagnosis. This study aimed to explore terahertz technology's application in colitis-associated cancer using a mouse model. Mouse colorectal tissues were transformed into paraffin-embedded blocks for histopathological analysis using HE staining. Terahertz transmission spectroscopy was performed on the tissue blocks. By comparing terahertz absorption differences, specific frequency bands were identified as optimal for distinguishing cancerous and normal tissues. The study revealed that terahertz spectroscopy effectively differentiates colitis-related cancers from normal tissues. Remarkably, 1.8 THz emerged as a potential optimal frequency for diagnosing colorectal cancer in mice. This suggests the potential for rapid histopathological diagnosis of colorectal cancer using terahertz technology.

EPAS1 Promoter Hypermethylation is a Diagnostic and Prognostic Biomarker for Non-Small Cell Lung Cancer.

Background: The importance of promoter methylation in non-small cell lung cancers (NSCLC) remains to be understood. Thus, we aimed to determine the diagnostic and prognostic value of the methylation of the endothelial PAS domain containing protein-1 (EPAS1) promoter in NSCLC. Methods: EPAS1 promoter methylation levels were quantitated by methylation-specific PCR. Further, we evaluated the expression, promoter methylation, prognostic value, and impact on immune cell infiltration of EPAS1 by analyzing the TCGA database using web-based bioinformatics tools including GEPIA, UALCAN and MethSurv. Results: Our results demonstrated that promoter methylation of EPAS1 downregulated its expression in NSCLC tissues. Additionally, an AUC value of 0.772 indicated that the methylation of the EPAS1 promoter is a potential diagnostic marker for NSCLC. A Kaplan-Meier analysis demonstrated that high methylation levels of CpG sites in the EPAS1 promoter were indicative of poorer overall survival. Further, EPAS1 expression levels were highly correlated with the infiltration of several types of immune cells, including γδ T cells, T follicular helper cells, CD8+ T cells, and CD4+ T-cells. Conclusion: Collectively, our findings suggest that methylation analyses of the EPAS1 promoter could be used as a prognostic biomarker for NSCLC and that EPAS1 potentially plays an important role in immune cell infiltration in NSCLC.

An immune gene signature to predict prognosis and immunotherapeutic response in lung adenocarcinoma.

Lung adenocarcinoma is one of the most common malignant tumors worldwide. The purpose of this study was to construct a stable immune gene signature for prediction of prognosis (IGSPP) and response to immune checkpoint inhibitors (ICIs) therapy in LUAD patients. Five genes were screened by weighted gene coexpression network analysis, Cox regression and LASSO regression analyses and were used to construct the IGSPP. The survival rate of the IGSPP low-risk group was higher than that of the IGSPP high-risk group. Multivariate Cox regression analysis showed that IGSPP could be used as an independent prognostic factor for the overall survival of LUAD patients. IGSPP genes were enriched in cell cycle pathways. IGSPP gene mutation rates were higher in the high-risk group. CD4 memory-activated T cells, M0 and M1 macrophages had higher infiltration abundance in the high-risk group, which was associated with poor overall survival. In contrast, the abundance of resting CD4 memory T cells, monocytes, resting dendritic cells and resting mast cells associated with a better prognosis was higher in the low-risk group. TIDE scores and the expressions of different immune checkpoints showed that patients in the high-risk IGSPP group benefited more from ICIs treatment. In short, an IGSPP of LUAD was constructed and characterized. It could be used to predict the prognosis and benefits of ICIs treatment in LUAD patients.

PRKCDBP Methylation is a Potential and Promising Candidate Biomarker for Non-small Cell Lung Cancer.

BACKGROUND: The occurrence and development of lung cancer are closely linked to epigenetic modification. Abnormal DNA methylation in the CpG island region of genes has been found in many cancers. Protein kinase C delta binding protein (PRKCDBP) is a potential tumor suppressor and its epigenetic changes are found in many human malignancies. This study investigated the possibility of PRKCDBP methylation as a potential biomarker for non-small cell lung cancer (NSCLC). METHODS: We measured the methylation levels of PRKCDBP in the three groups of NSCLC tissues. Promoter activity was measured by the dual luciferase assay, with 5'-aza-deoxycytidine to examine the effect of demethylation on the expression level of PRKCDBP. RESULTS: The methylation levels of PRKCDBP in tumor tissues and 3 cm para-tumor were higher than those of distant (>10 cm) non-tumor tissues. Receiver operating characteristic (ROC) curve analysis between tumor tissues and distant non-tumor tissues showed that the area under the line (AUC) was 0.717. Dual luciferase experiment confirmed that the promoter region was able to promote gene expression. Meanwhile, in vitro methylation of the fragment (PRKCDBP_Me) could significantly reduce the promoter activity of the fragment. Demethylation of 5'-aza-deoxycytidine in lung cancer cell lines A549 and H1299 showed a significant up-regulation of PRKCDBP mRNA levels. CONCLUSIONS: PRKCDBP methylation is a potential and promising candidate biomarker for non-small cell lung cancer.

LINC00662: A new oncogenic lncRNA with great potential.

LINC00662 is located on chromosome 19q11 and is 2085 bp long. It is a long noncoding RNA (lncRNA) newly discovered. LINC00662 expression is upregulated in at least 14 tumors. In addition, the upregulation of LINC00662 expression is also closely related to the poor prognosis of cancer patients and resistance to radiotherapy and chemotherapy. LINC00662 can act as a ceRNA of at least 8 miRNAs. By regulating these miRNAs and their downstream genes, LINC00662 participates in the regulation of four signaling pathways, including the extracellular signal-regulated kinase (ERK) signaling pathway, the Wnt/ß-catenin signaling pathway, the Hippo signaling pathway, and the SMD signaling pathway. In addition, the abnormal upregulation of LINC00662 can promote the stem-like features of lung cancer cells. LINC00662 can reduce the promoter methylation level of s-adenosylmethionine (SAM)-dependent hepatocellular carcinoma (HCC)-promoting genes by regulating the MAT1A/SAM and AHCY/SAH axes, thereby promoting the activation of oncogenes. This article summarizes the molecular regulation mechanism of LINC00662 in cancer and the diagnostic and prognostic value of LINC00662 in cancer.

Hypermethylation of tumor necrosis factor decoy receptor gene in non-small cell lung cancer.

Abnormal methylation of the TNFRSF10C and TNFRSF10D genes has been observed in numerous types of cancer; however, no studies have investigated the methylation of these genes in non-small cell lung cancer (NSCLC). The aim of the present study was to investigate the association between TNFRSF10C and TNFRSF10D methylation and NSCLC. Methylation levels of 44 pairs of NSCLC tumor tissues and distant non-tumor tissues were analyzed using quantitative methylation specific PCR and methylation reference percentage values (PMR). The methylation levels of the TNFRSF10C gene in NSCLC tumor tissue samples were significantly higher compared with those in the distant non-tumor tissues (median PMR, 2.73% vs. 0.75%; P=0.013). Subgroup analysis demonstrated that the methylation levels of TNFRSF10C in tumor tissues from male patients were significantly higher compared with those in distant non-tumor tissues (median PMR, 2.73% vs. 0.75%; P=0.041). The levels of TNFRSF10C methylation were also higher in the tumor tissues of patients who were non-smokers compared with their distant non-tumor tissues (median PMR, 2.50% vs. 0.63%; P=0.013). TNFRSF10C methylation levels were higher in the tumor tissues from male patients compared with those from female patients (median PMR, 2.50% vs. 0.63%; P=0.031). However, no significant differences in the methylation levels of the TNFRSF10D gene were observed between the sexes. Using the cBioPortal and The Cancer Genome Atlas lung cancer data, it was demonstrated that TNFRSF10C methylation levels were inversely correlated with TNFRSF10C mRNA expression levels (r=-0.379; P=0.008). In addition, demethylation of lung cancer cell lines A549 and NCI-H1299 using 5'-aza-deoxycytidine further confirmed that TNFRSF10C hypomethylation was associated with significant upregulation of TNFRSF10C mRNA expression levels [A549 fold-change (FC)=8; P=1.0×10-4; NCI-H1299 FC=3.163; P=1.143×10-5]. A dual luciferase reporter gene assay was also performed with the insert of TNFRSF10C promoter region, and the results revealed that the TNFRSF10C gene fragment significantly enhanced the transcriptional activity of the reporter gene compared with that in the control group (FC=1.570; P=0.032). Overall, the results of the present study demonstrated that hypermethylation of TNFRSF10C was associated with NSCLC.

The deubiquitinating enzyme OTUD1 antagonizes BH3-mimetic inhibitor induced cell death through regulating the stability of the MCL1 protein.

BACKGROUND: Myeloid cell leukaemia 1 (MCL1) is a pro-survival Bcl-2 family protein that plays important roles in cell survival, proliferation, differentiation and tumourigenesis. MCL1 is a fast-turnover protein that is degraded via an ubiquitination/proteasome-dependent mechanism. Although several E3 ligases have been discovered to promote the ubiquitination of MCL1, the deubiquitinating enzyme (DUB) that regulates its stability requires further investigation. METHODS: The immunoprecipitation was used to determine the interaction between OTUD1 and MCL1. The ubiquitination assays was performed to determine the regulation of MCL1 by OTUD1. The cell viability was used to determine the regulation of BH3-mimetic inhibitor induced cell death by OTUD1. The survival analysis was used to determine the relationship between OTUD1 expression levels and the survival rate of cancer patients. RESULTS: By screening a DUB expression library, we determined that the deubiquitinating enzyme OTUD1 regulates MCL1 protein stability in an enzymatic-activity dependent manner. OTUD1 interacts with MCL1 and promotes its deubiquitination. Knockdown of OTUD1 increases the sensitivity of tumour cells to the BH3-mimetic inhibitor ABT-263, while overexpression of OTUD1 increases tumour cell tolerance of ABT-263. Furthermore, bioinformatics analysis data reveal that OTUD1 is a negative prognostic factor for liver cancer, ovarian cancer and specific subtypes of breast and cervical cancer. CONCLUSIONS: The deubiquitinating enzyme OTUD1 antagonizes BH3-mimetic inhibitor induced cell death through regulating the stability of the MCL1 protein. Thus, OTUD1 could be considered as a therapeutic target for curing these cancers.

AIM2 inflammasome mediates Arsenic-induced secretion of IL-1 ß and IL-18.

Chronic sterile inflammation has been implicated in the pathogenesis of many cancers, including skin cancer. Chronic arsenic exposure is closely associated with the development of skin cancer. However, there is a lack of understanding how arsenic induces chronic inflammation in the skin. Interleukin-1 family cytokines play a central role in regulating immune and inflammatory response. IL-1α, IL-1ß and IL-18 are three pro-inflammatory cytokines in IL-1 family. Their secretion, especially the secretion of IL-1ß and IL-18, is regulated by inflammasomes which are multi-protein complexes containing sensor proteins, adaptor protein and caspase-1. The data from current study show sub-chronic arsenic exposure activates AIM2 inflammasome which in turn activates caspase-1 and enhances the secretion of IL-1ß and IL-18 in HaCaT cells and the skin of BALB/c mice. In addition, arsenic-promoted activation of AIM2 inflammasome and increase of IL-1ß/IL-18 production are inhibited by PKR inhibitor in HaCaT cells or in the skin of PKR mutant mice, indicating a potential role of PKR in arsenic-induced sterile inflammation.

Role of MCP-1 in alcohol-induced aggressiveness of colorectal cancer cells.

Epidemiological studies demonstrate that alcohol consumption is associated with an increased risk of colorectal cancer (CRC). In addition to promoting carcinogenesis, alcohol may also accelerate the progression of existing CRC. We hypothesized that alcohol may enhance the aggressiveness of CRC. In this study, we investigated the effect of alcohol on the migration/invasion and metastasis of CRC. Alcohol increased the migration/invasion of colorectal cancer cells (DLD1, HCT116, HT29, and SW480) in a concentration-dependent manner. Among these colon cancer cell lines, HCT116 cells were most responsive while HT29 cells were the least responsive to ethanol-stimulated cell migration/invasion. These in vitro results were supported by animal studies which demonstrated that ethanol enhanced the metastasis of colorectal cancer cells to the liver and lung. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that plays an important role in regulating tumor microenvironment and metastasis. Alcohol increased the expression of MCP-1 and its receptor CCR2 at both protein and mRNA levels. The pattern of alcohol-induced alterations in MCP-1 expression was consistent with its effect on migration/invasion; HCT116 cells displayed the highest up-regulation of MCP-1/CCR2 in response to alcohol exposure. An antagonist of CCR2 blocked alcohol-stimulated migration. Alcohol caused an initial cytosolic accumulation of ß-catenin and its subsequent nuclear translocation by inhibiting GSK3ß activity. Alcohol stimulated the activity of MCP-1 gene promoter in a ß-catenin-dependent manner. Furthermore, knock-down of MCP-1/CCR2 or ß-catenin was sufficient to inhibit alcohol-induced cell migration/invasion. Together, these results suggested that alcohol may promote the metastasis of CRC through modulating GSK3ß/ß-catenin/MCP-1 pathway.

Association of THBS1 rs1478605 T>C in 5'-untranslated regions with the development and progression of gastric cancer.

Thrombospondin 1 (THBS1) plays an important role in angiogenesis and tumor progression. The aim of the present study was to investigate the effects of single-nucleotide polymorphisms (rs1478605 and rs3743125) in the untranslated regions of the THBS1 gene on the development and progression of gastric cancer. In the case-control study, 275 gastric cancer patients and 275 cancer-free controls were successfully genotyped using polymerase chain reaction-restriction fragment length polymorphism. The data demonstrated that THBS1 rs1478605 genotypic distributions significantly differed between the patient and control groups (P=0.005). Carriers of the CC genotype exhibited a decreased risk of developing gastric cancer compared to the carriers of the CT and TT genotypes [adjusted odd ratio (OR), 0.56; 95% confidence interval (CI), 0.39-0.79; P=0.001]. The CC genotype of rs1478605 was negatively associated with gastric cancer lymph node metastasis (OR, 0.41; 95% CI, 0.23-0.71; P=0.001) and was associated with a reduced risk of lymph node metastasis in male patients (OR, 0.27; 95% CI, 0.14-0.52; P<0.001). The THBS1 CT haplotype was associated with a reduced risk of developing gastric cancer (OR, 0.56; 95% CI, 0.33-0.93; P=0.02). By contrast, no association was observed between THBS1 rs3743125 and the development and progression of gastric cancer. These results suggest that THBS1 rs1478605 represents a potential molecular marker for gastric cancer.

Deficient PKR in RAX/PKR Association Ameliorates Ethanol-Induced Neurotoxicity in the Developing Cerebellum.

Ethanol-induced neuronal loss is closely related to the pathogenesis of fetal alcohol spectrum disorders. The cerebellum is one of the brain areas that are most sensitive to ethanol. The mechanism underlying ethanol neurotoxicity remains unclear. Our previous in vitro studies have shown that the double-stranded RNA (dsRNA)-activated protein kinase (PKR) regulates neuronal apoptosis upon ethanol exposure and ethanol activates PKR through association with its intracellular activator RAX. However, the role of PKR and its interaction with RAX in vivo have not been investigated. In the current study, by utilizing N-PKR-/- mice, C57BL/6J mice with a deficient RAX-binding domain in PKR, we determined the critical role of RAX/PKR association in PKR-regulated ethanol neurotoxicity in the developing cerebellum. Our data indicate that while N-PKR-/- mice have a similar BAC profile as wild-type mice, ethanol induces less brain/body mass reduction as well as cerebellar neuronal loss. In addition, ethanol promotes interleukin-1ß (IL-1ß) secretion, and IL-1ß is a master cytokine regulating inflammatory response. Importantly, ethanol-promoted IL-1ß secretion is inhibited in the developing cerebellum of N-PKR-/- mice. Thus, RAX/PKR interaction and PKR activation regulate ethanol neurotoxicity in the developing cerebellum, which may involve ethanol-induced neuroinflammation. Further, PKR could be a possible target for pharmacological intervention to prevent or treat fetal alcohol spectrum disorder (FASD).

Autophagy inhibition by sustained overproduction of IL6 contributes to arsenic carcinogenesis.

Chronic inflammation has been implicated as an etiologic factor in cancer, whereas autophagy may help preserve cancer cell survival but exert anti-inflammatory effects. How these phenomenas interact during carcinogenesis remains unclear. We explored this question in a human bronchial epithelial cell-based model of lung carcinogenesis that is mediated by subchronic exposure to arsenic. We found that sustained overexpression of the pro-inflammatory IL6 promoted arsenic-induced cell transformation by inhibiting autophagy. Conversely, strategies to enhance autophagy counteracted the effect of IL6 in the model. These findings were confirmed and extended in a mouse model of arsenic-induced lung cancer. Mechanistic investigations suggested that mTOR inhibition contributed to the activation of autophagy, whereas IL6 overexpression was sufficient to block autophagy by supporting Beclin-1/Mcl-1 interaction. Overall, our findings argued that chronic inflammatory states driven by IL6 could antagonize autophagic states that may help preserve cancer cell survival and promote malignant progression, suggesting a need to uncouple inflammation and autophagy controls to enable tumor progression.

MicroRNA-29b regulates ethanol-induced neuronal apoptosis in the developing cerebellum through SP1/RAX/PKR cascade.

Neuronal loss is a prominent etiological factor for fetal alcohol spectrum disorders. The cerebellum is one of the areas in the developing central nervous system that is most sensitive to ethanol, especially during the temporal window of ethanol vulnerability. MicroRNAs are small, non-coding RNAs capable of regulating diverse cellular functions including apoptosis. Ethanol exposure has been shown to interfere with the expression of microRNAs. However, the role of microRNAs in ethanol neurotoxicity is still not clear. In the present study, we identified a particular microRNA, miR-29b, as a novel target of ethanol in the developing cerebellar granule neurons. We discovered that ethanol exposure suppressed miR-29b and induced neuronal apoptosis. Overexpression of miR-29b rendered neurons protection against ethanol-induced apoptosis. Furthermore, our data indicated that miR-29b mediated ethanol neurotoxicity through the SP1/RAX/PKR cascade. More importantly, the expression of miR-29b is developmentally regulated, which may account for, at least partially, the temporal window of ethanol sensitivity in the developing cerebellum.

Autophagy in arsenic carcinogenesis.

Chronic exposure to arsenic may cause cancer. Many mechanisms have been suggested for arsenic carcinogenesis. Autophagy, an evolutionarily conserved cellular catabolic mechanism, has been implicated in cancer biology. Although being claimed as a type of cell death, autophagy may actually serve as a cell self-defense mechanism. In this review article, current understandings of the mechanisms of arsenic carcinogenesis, functions of autophagy and the role of autophagy in arsenic carcinogenesis are discussed.

[Effects of eEF1A1 re-expression on proliferation and apoptosis of Jurkat cells with knocked down eEF1A1 gene and its mechanisms].

This study was aimed to explore the effects of expressing eukaryotic elongation factor 1A1 (eEF1A1) on proliferation and apoptosis in human acute T lymphocytic leukemia (T-ALL) cell line Jurkat with knocked down eEF1A1 gene and its mechanisms. eEF1A1-expressing lentivirus (LV) was constructed and used to transfect the Jurkat cells with knocked down eEF1A1 gene. Then, the expressions of eEF1A1 mRNA and protein were detected by real time PCR(RT-PCR) and Western blot respectively.Cell proliferation, apoptosis and cycle were detected by MTT method, Annexin V-APC labeling and DNA ploidy analysis respectively. The related protein expressions of phosphatidylinositol-3-kinase (PI3K)/serine/threonine kinase (Akt) signaling pathway were detected by Western blot. The results indicated that eEF1A1 mRNA and protein expressions of Jurkat cells with knocked down eEF1A1 gene were re-established by constructing eEF1A1-expression LV. Compared with negative control group (transfected with negative control LV and eEF1A1-shRNA LV), cell proliferation in eEF1A1 expression group was significantly enhanced, cell apoptosis was remarkably inhibited, percentage of cells in G0/G1 phase was significantly reduced alone with increased percentage of cells in S and G2/M phase, and the expression levels of p-Akt (Ser 473), nuclear factor kappa B (NF-κB), p-NF-κB (Ser 468), mammalian target of rapamycin (mTOR) and p-mTOR (Ser 2448) protein significantly increased. It is concluded that eEF1A1 may have a carcinogenic effect in T-ALL cells. eEF1A1 expression has noticeable effects on the proliferation enhancement and apoptosis inhibition of Jurkat cells, which may be mediated by the up-regulation of PI3K/Akt/NF-κB and PI3K/Akt/ mTOR signaling pathway.

Recombinant snake venom cystatin inhibits tumor angiogenesis in vitro and in vivo associated with downregulation of VEGF-A165, Flt-1 and bFGF.

Previous studies have shown that recombinant snake venom cystatin (sv-cystatin) inhibits the invasion and metastasis of tumor cells in vitro and in vivo. The purpose of this study was to investigate the ability of recombinant sv-cystatin to inhibit tumor angiogenesis in vitro and in vivo, and the mechanisms underlying this effect. Recombinant sv-cystatin inhibited proliferation of human umbilical vein endothelial cells (HUVECs) at 100 and 200 µg/mL after 72, 96 and 120 h. Recombinant sv-cystatin also inhibited tumor-endothelial cell adhesion at 25, 50, 100 and 200 µg/mL. Recombinant sv-cystatin inhibited capillary-like tube formation by HUVECs at 10, 25, 50, 100 and 200 µg/mL following 12, 24 and 36 h incubation. Furthermore, recombinant sv-cystatin significantly suppressed microvessel density (MVD) of lung tumor colonies in C57BL/6 mice inoculated in the lateral tail vein with B16F10 melanoma cells. Administration of recombinant sv-cystatin significantly decreased MVD of primary tumor tissues in nude mice implanted subcutaneously with human hepatocellular carcinoma cells (MHCC97H). Exposure of B16F10 and MHCC97H cells to increasing doses of recombinant sv-cystatin suppressed secretion of vascular endothelial growth factor (VEGF)-A165 and basic fibroblast growth factor (bFGF) into the surrounding medium (P < 0.05). The expression of fms-related tyrosine kinase 1 (Flt-1) protein in HUVECs was decreased by 25, 50, 100 and 200 µg/mL recombinant sv-cystatin (P < 0.05). This study demonstrates that recombinant sv-cystatin inhibits tumor angiogenesis associated with downregulation of VEGF-A165, Flt-1 and bFGF. This suggests that recombinant sv-cystatin may have potential pharmaceutical applications as an antiangiogenic and antimetastatic therapeutic agent.

[Effect of knocking down eEF1A1 gene on proliferation and apoptosis in Jurkat cells and its mechanisms].

This study was purposed to investigate the effect of knocking down eukaryotic elongation factor 1A1 (eEF1A1) gene on the proliferation and apoptosis in human acute T lymphocytic leukemia (T-ALL) cell line Jurkat and explore its mechanism. The eEF1A1 mRNA and protein expressions of Jurkat cells and 3 healthy adult peripheral blood mononuclear cells (PBMNC) were detected by real time PCR and Western blot, respectively. eEF1A1-shRNA lentivirus was constructed through molecular biological method, and was used to transfect Jurkat cells. Then, cell eEF1A1 mRNA and protein expressions were detected by real time PCR and Western blot, respectively. Cell proliferation, apoptosis and cycle were detected by MTT method, Annexin V-APC labeling and DNA ploidy analysis, respectively. Cell-related protein expressions of phosphatidylinositol-3-kinase (PI3K)/serine/threonine kinase (Akt) signaling pathway were detected by Western blot. The results showed that eEF1A1 mRNA and protein expression levels of Jurkat cells were significantly higher than that of healthy adult PBMNC, respectively (P < 0.01, P < 0.05). eEF1A1 mRNA and protein expressions of Jurkat cells were significantly knocked down by constructing eEF1A1-shRNA lentivirus. Compared to negative control group (transfected with negative control-shRNA lentivirus), cell proliferation in eEF1A1-shRNA group was significantly inhibited, cell apoptosis was remarkably induced, cell cycle was blocked in G(0)/G(1) phase, and the expression levels of p-Akt (Ser 473), nuclear factor kappa B (NF-κB), p-NF-κB (Ser 468), mammalian target of rapamycin (mTOR) and p-mTOR (Ser 2448) proteins were significantly reduced. It is concluded that eEF1A1 may be a putative oncoprotein in T-ALL cells. Knocking down eEF1A1 gene has noticeable effects on the proliferation inhibition and apoptosis induction of Jurkat cells, which may be mediated by the down-regulation of PI3K/Akt/NF-κB and PI3K/Akt/mTOR signaling pathway.

Autophagy is a cell self-protective mechanism against arsenic-induced cell transformation.

Subchronic exposure to arsenic increases the incidence of human cancers such as skin, lung, colon, and rectal cancer. The mechanism for arsenic-induced tumorigenesis is still not clear. It is generally believed that DNA damage and genomic instability, generated by arsenic-promoted oxidative stress, account largely for this process. The major sources of reactive oxygen species (ROS) are arsenic-damaged mitochondria. Autophagy is a catabolic process functioning in turnover of long-lived proteins and dysfunctional organelles such as mitochondria. Defects of autophagy under stress conditions promote genomic instability and increase the risk of tumorigenesis. In the present study using a human bronchial epithelial cell line, BEAS-2B cells, we investigated the role of autophagy in arsenic-induced cell transformation, an important step in arsenic tumorigenesis. Our results show that subchronic arsenic exposure induces BEAS-2B cell transformation accompanied with increased ROS generation and autophagy activation. However, the patterns for ROS and autophagy alteration are different. Arsenic exposure generated a prolonged and steady increase of ROS levels, whereas the activation of autophagy, after an initial boost by arsenic administration, decreases in response to subchronic arsenic exposure, although the activity is still higher than a nontreated control. Further stimulation of autophagy increases mitochondria turnover and decreases ROS generation and arsenic-induced cell transformation. Contrarily, inhibition of autophagy activity decreases mitochondria turnover and enhances arsenic-induced ROS generation and cell transformation. In addition, the mammalian target of rapamycin signaling pathway is involved in arsenic-mediated autophagy activation. Our results suggest that autophagy is a cell self-protective mechanism against arsenic-induced cell transformation.

Autophagy is a protective response to ethanol neurotoxicity.

Ethanol is a neuroteratogen and neurodegeneration is the most devastating consequence of developmental exposure to ethanol. The mechanisms underlying ethanol-induced neurodegeneration are complex. Ethanol exposure produces reactive oxygen species (ROS) which cause oxidative stress in the brain. We hypothesized that ethanol would activate autophagy to alleviate oxidative stress and neurotoxicity. Our results indicated that ethanol increased the level of the autophagic marker Map1lc3-II (LC3-II) and upregulated LC3 puncta in SH-SY5Y neuroblastoma cells. It also enhanced the levels of LC3-II and BECN1 in the developing brain; meanwhile, ethanol reduced SQSTM1 (p62) levels. Bafilomycin A(1), an inhibitor of autophagosome and lysosome fusion, increased p62 levels in the presence of ethanol. Bafilomycin A(1) and rapamycin potentiated ethanol-increased LC3 lipidation, whereas wortmannin and a BECN1-specific shRNA inhibited ethanol-promoted LC3 lipidation. Ethanol increased mitophagy, which was also modulated by BECN1 shRNA and rapamycin. The evidence suggested that ethanol promoted autophagic flux. Activation of autophagy by rapamycin reduced ethanol-induced ROS generation and ameliorated ethanol-induced neuronal death in vitro and in the developing brain, whereas inhibition of autophagy by wortmannin and BECN1-specific shRNA potentiated ethanol-induced ROS production and exacerbated ethanol neurotoxicity. Furthermore, ethanol inhibited the MTOR pathway and downregulation of MTOR offered neuroprotection. Taken together, the results suggest that autophagy activation is a neuroprotective response to alleviate ethanol toxicity. Ethanol modulation of autophagic activity may be mediated by the MTOR pathway.