The LMP7-K allele of the immunoproteasome exhibits reduced transcript stability and predicts high risk of colon cancer

The role of proteasomes in tumorigenesis

Protein homeostasis is the basis of normal life activities, and the proteasome family plays an extremely important function in this process. The proteasome 20S is a concentric circle structure with two α rings and two β rings overlapped. The proteasome 20S can perform both ATP-dependent and non-ATP-dependent ubiquitination proteasome degradation by binding to various subunits (such as 19S, 11S, and 200 PA), which is performed by its active subunit β1, β2, and β5. The proteasome can degrade misfolded, excess proteins to maintain homeostasis. At the same time, it can be utilized by tumors to degrade over-proliferate and unwanted proteins to support their growth. Proteasomes can affect the development of tumors from several aspects including tumor signaling pathways such as NF-κB and p53, cell cycle, immune regulation, and drug resistance. Proteasome-encoding genes have been found to be overexpressed in a variety of tumors, providing a potential novel target for cancer therapy. In addition, proteasome inhibitors such as bortezomib, carfilzomib, and ixazomib have been put into clinical application as the first-line treatment of multiple myeloma. More and more studies have shown that it also has different therapeutic effects in other tumors such as hepatocellular carcinoma, non-small cell lung cancer, glioblastoma, and neuroblastoma. However, proteasome inhibitors are not much effective due to their tolerance and singleness in other tumors. Therefore, further studies on their mechanisms of action and drug interactions are needed to investigate their therapeutic potential.

Expression of thimet oligopeptidase (THOP) modulated by oxidative stress in human multidrug resistant (MDR) leukemia cells

Thimet oligopeptidase (THOP) is a cytosolic metallopeptidase known to regulate the fate of post-proteasomal peptides, protein turnover and peptide selection in the antigen presentation machinery (APM) system. Oxidative stress influences THOP expression and regulates its proteolytic activity, generating variable cytosolic peptide levels, possibly affecting the immune evasion of tumor cells. In the present work, we examined the association between THOP expression/activity and stress oxidative resistance in human leukemia cells using the K562 cell line, a chronic myeloid leukemia (CML), and the multidrug-resistant (MDR) Lucena 1 (K562-derived MDR cell line) as model. The Lucena 1 phenotype was validated under vincristine treatment and the relative THOP1 mRNA levels and protein expression compared to K562 cell line. Our data demonstrated increased THOP1 gene and protein levels in K562 cells in contrast to the oxidative-resistant Lucena 1, even after H2O2 treatment, suggesting an oxidative stress dependence in THOP regulation. Further, it was observed higher basal levels of reactive oxygen species (ROS) in K562 compared to Lucena 1 cell line using DHE fluorescent probe. Since THOP activity is dependent on its oligomeric state, we also compared its proteolytic activity under reducing agent treatment, which demonstrated that its function modulation with respect to changes in redox state. Finally, the mRNA expression and FACS analyses demonstrated a reduced expression of MHC I only in K562 cell line. In conclusion, our results highlight THOP redox modulation, which could influence antigen presentation in multidrug resistant leukemia cells.

The Functional and Mechanistic Roles of Immunoproteasome Subunits in Cancer

Cell-mediated immunity is driven by antigenic peptide presentation on major histocompatibility complex (MHC) molecules. Specialized proteasome complexes called immunoproteasomes process viral, bacterial, and tumor antigens for presentation on MHC class I molecules, which can induce CD8 T cells to mount effective immune responses. Immunoproteasomes are distinguished by three subunits that alter the catalytic activity of the proteasome and are inducible by inflammatory stimuli such as interferon-γ (IFN-γ). This inducible activity places them in central roles in cancer, autoimmunity, and inflammation. While accelerated proteasomal degradation is an important tumorigenic mechanism deployed by several cancers, there is some ambiguity regarding the role of immunoproteasome induction in neoplastic transformation. Understanding the mechanistic and functional relevance of the immunoproteasome provides essential insights into developing targeted therapies, including overcoming resistance to standard proteasome inhibition and immunomodulation of the tumor microenvironment. In this review, we discuss the roles of the immunoproteasome in different cancers.

At the Cutting Edge against Cancer: A Perspective on Immunoproteasome and Immune Checkpoints Modulation as a Potential Therapeutic Intervention

Immunoproteasome is a noncanonical form of proteasome with enzymological properties optimized for the generation of antigenic peptides presented in complex with class I MHC molecules. This enzymatic property makes the modulation of its activity a promising area of research. Nevertheless, immunotherapy has emerged as a front-line treatment of advanced/metastatic tumors providing outstanding improvement of life expectancy, even though not all patients achieve a long-lasting clinical benefit. To enhance the efficacy of the currently available immunotherapies and enable the development of new strategies, a broader knowledge of the dynamics of antigen repertoire processing by cancer cells is needed. Therefore, a better understanding of the role of immunoproteasome in antigen processing and of the therapeutic implication of its modulation is mandatory. Studies on the potential crosstalk between proteasome modulators and immune checkpoint inhibitors could provide novel perspectives and an unexplored treatment option for a variety of cancers.

Gatekeepers of the Gut: The Roles of Proteasomes at the Gastrointestinal Barrier

The gut epithelial barrier provides the first line of defense protecting the internal milieu from the environment. To circumvent the exposure to constant challenges such as pathogenic infections and commensal bacteria, epithelial and immune cells at the gut barrier require rapid and efficient means to dynamically sense and respond to stimuli. Numerous studies have highlighted the importance of proteolysis in maintaining homeostasis and adapting to the dynamic changes of the conditions in the gut environment. Primarily, proteolytic activities that are involved in immune regulation and inflammation have been examined in the context of the lysosome and inflammasome activation. Yet, the key to cellular and tissue proteostasis is the ubiquitin–proteasome system, which tightly regulates fundamental aspects of inflammatory signaling and protein quality control to provide rapid responses and protect from the accumulation of proteotoxic damage. In this review, we discuss proteasome-dependent regulation of the gut and highlight the pathophysiological consequences of the disarray of proteasomal control in the gut, in the context of aberrant inflammatory disorders and tumorigenesis.

Immunoproteasome Function in Normal and Malignant Hematopoiesis

The ubiquitin-proteasome system (UPS) is a central part of protein homeostasis, degrading not only misfolded or oxidized proteins but also proteins with essential functions. The fact that a healthy hematopoietic system relies on the regulation of protein homeostasis and that alterations in the UPS can lead to malignant transformation makes the UPS an attractive therapeutic target for the treatment of hematologic malignancies. Herein, inhibitors of the proteasome, the last and most important component of the UPS enzymatic cascade, have been approved for the treatment of these malignancies. However, their use has been associated with side effects, drug resistance, and relapse. Inhibitors of the immunoproteasome, a proteasomal variant constitutively expressed in the cells of hematopoietic origin, could potentially overcome the encountered problems of non-selective proteasome inhibition. Immunoproteasome inhibitors have demonstrated their efficacy and safety against inflammatory and autoimmune diseases, even though their development for the treatment of hematologic malignancies is still in the early phases. Various immunoproteasome inhibitors have shown promising preliminary results in pre-clinical studies, and one inhibitor is currently being investigated in clinical trials for the treatment of multiple myeloma. Here, we will review data on immunoproteasome function and inhibition in hematopoietic cells and hematologic cancers.

Polymorphisms of Antigen-Presenting Machinery Genes in Non-Small Cell Lung Cancer: Different Impact on Disease Risk and Clinical Parameters in Smokers and Never-Smokers

Lung cancer is strongly associated with cigarette smoking; nevertheless some never-smokers develop cancer. Immune eradication of cancer cells is dependent on polymorphisms of HLA class I molecules and antigen-processing machinery (APM) components. We have already published highly significant associations of single nucleotide polymorphisms (SNPs) of the ERAP1 gene with non-small cell lung cancer (NSCLC) in Chinese, but not in Polish populations. However, the smoking status of participants was not known in the previous study. Here, we compared the distribution of APM polymorphic variants in larger cohorts of Polish patients with NSCLC and controls, stratified according to their smoking status. We found significant but opposite associations in never-smokers and in smokers of all tested SNPs (rs26653, rs2287987, rs30187, and rs27044) but one (rs26618) in ERAP1. No significant associations were seen in other genes. Haplotype analysis indicated that the distribution of many ERAP1/2 haplotypes is opposite, depending on smoking status. Additionally, haplotypic combination of low activity ERAP1 and the lack of an active form of ERAP2 seems to favor the disease in never-smokers. We also revealed interesting associations of some APM polymorphisms with: age at diagnosis (ERAP1 rs26653), disease stage (ERAP1 rs27044, PSMB9 rs17587), overall survival (ERAP1 rs30187), and response to chemotherapy (ERAP1 rs27044). The results presented here may suggest the important role for ERAP1 in the anti-cancer response, which is different in smokers versus never-smokers, depending to some extent on the presence of ERAP2, and affecting NSCLC clinical course.

LMP7 polymorphism may modify the presentation and clinical impact of minor histocompatibility antigens in matched related hematopoietic stem cell transplantation

Differential expression of minor histocompatibility antigens between the recipient and donor determines their disparity and can be modified by immunoproteasomes that regulate their processing and presentation. We examined the impact of HA-1 and HA-8 disparity, and immunoproteasome LMP7 polymorphism in 130 pairs. In multivariate analysis, HA-1 disparity showed a statistically significant association with an increased incidence of acute graft-versus-host disease (aGVHD) II-IV (p = 0.043, HR: 3.71, 95%CI = 1.04-13.26), while LMP7-Q/Q showed a trend toward increased incidence of aGVHD compared to LMP7-Q/K and K/K genotypes (p = 0.087, HR: 2.36, 95%CI = 0.88-6.31). All HA-1 and HA-8 disparate patients who developed aGVHD had the LMP7-Q/Q genotype. No significant association could be detected between HA-1, HA-8, or LMP7 and chronic GVHD, relapse-free survival (RFS), overall survival (OS), or transplant-related mortality (TRM). In conclusion, we suggested an association between the HA-1 disparity and the risk of developing aGVHD with a possible modifying effect of LMP7.

Association between the TAP1 gene polymorphisms and recurrent respiratory papillomatosis in patients from Western Mexico: A pilot study

Background

Recurrent respiratory papillomatosis (RRP) is a respiratory tract disease that affects children and adults and is characterized by the recurrent proliferation of multiple papillomas. The etiologic agent is the human papillomavirus, mainly genotypes 6 and 11. Furthermore, polymorphisms in TAP1 appear to influence the selection of antigenic peptides and the transport process to the rough endoplasmic reticulum, for their subsequent presentation to T lymphocytes, an essential process against viral diseases and tumor processes. Previous studies have shown that individuals with those polymorphisms are susceptible to immune, infectious, and tumor‐related diseases. The present study aimed to determine the association between the TAP1 rs1057141 (c.1177A>G) and rs1135216 (c.2090A>G) single nucleotide polymorphisms (SNPs) and RRP.

Methods

A case–control study was carried out on a group of 70 individuals (35 controls and 35 patients). RRP diagnosis, HPV genotyping, and viral load were determined through histology and PCR. SNPs rs1057141 and rs1135216 were identified through allelic discrimination, using real‐time PCR. The haplotypic analyses were performed using the Arlequin 3.5 program.

Results

HPV‐6 and HPV‐11 were the genotypes found in the samples. In the polymorphism analysis, rs1057141 showed no significant differences (p = 0.049, CI = 0.994–7.331). In contrast, a significant difference was found in rs1135216 (p = 0.039, OR = 2.4) in the allelic analysis, as well as in the dominant (p = 0.027, OR = 3.06), codominant (p = 0.033, OR = 3.06), and additive model (p = 0.043, OR = 2.505) in subjects with the G allele.

Conclusion

The G allele in rs1135216 was associated with a genetic risk of susceptibility for RRP in a population in Western Mexico.

An Investigation Into the Prognostic Significance of High Proteasome PSB7 Protein Expression in Colorectal Cancer

Using unbiased proteomics, we had previously discovered that the catalytic proteasome subunit β type 7 (PSB7) protein is frequently overexpressed in colorectal adenocarcinomas. In this paper, we validate this finding and derive a prognostic significance for PSB7 by examining an expanded, well-annotated clinical cohort of 318 colorectal cancer patients. We found PSB7 protein levels to be similarly increased in both advanced stage primary disease and metastatic lesions. We then examined the prognostic value of PSB7 protein expression. Elevated PSB7 protein as well as PSMB7 mRNA levels showed associations with lower overall survival, particularly in female patients. The prognostic value of elevated PSB7 protein levels was highest for female patients who were older (>60 years of age at diagnosis) or who had received adjuvant chemotherapy. While high PSB7 did not retain its prognostic significance on multivariate analysis, we discuss the potential significance of PSB7 as a biomarker, considering its differential prognostic strength in different colorectal cancer patient groups and given its role as a subunit of the immunoproteasome for antigen presentation.

Untangling Extracellular Proteasome-Osteopontin Circuit Dynamics in Multiple Sclerosis

The function of proteasomes in extracellular space is still largely unknown. The extracellular proteasome-osteopontin circuit has recently been hypothesized to be part of the inflammatory machinery regulating relapse/remission phase alternation in multiple sclerosis. However, it is still unclear what dynamics there are between the different elements of the circuit, what the role of proteasome isoforms is, and whether these inflammatory circuit dynamics are associated with the clinical severity of multiple sclerosis. To shed light on these aspects of this novel inflammatory circuit, we integrated in vitro proteasome isoform data, cell chemotaxis cell culture data, and clinical data of multiple sclerosis cohorts in a coherent computational inference framework. Thereby, we modeled extracellular osteopontin-proteasome circuit dynamics during relapse/remission alternation in multiple sclerosis. Applying this computational framework to a longitudinal study on single multiple sclerosis patients suggests a complex interaction between extracellular proteasome isoforms and osteopontin with potential clinical implications.

Proteasome dysregulation in human cancer: implications for clinical therapies

Cancer cells show heightened dependency on the proteasome for their survival, growth, and spread. Proteasome dysregulation is therefore commonly selected in favor of the development of many types of cancer. The vast abnormalities in a cancer cell, on top of the complexity of the proteasome itself, have enabled a plethora of mechanisms gearing the proteasome to the oncogenic process. Here, we use selected examples to highlight some general mechanisms underlying proteasome dysregulation in cancer, including copy number variations, transcriptional control, epigenetic regulation, and post-translational modifications. Research in this field has greatly advanced our understanding of proteasome regulation and will shed new light on proteasome-based combination therapies for cancer treatment.

Impact of LMP7 (rs2071543) gene polymorphism in increasing cancer risk: evidence from a meta-analysis and trial sequential analysis

Genetic variant LMP7 (low molecular weight polypeptide 7) –145 C > A may influence the function of immune surveillance of an individual and lead to cancer development. Various studies have investigated the relevance of LMP7 –145 C > A gene polymorphism with cancer risk; but, their results are conflicting and inconsistent. To obtain a comprehensive conclusion, a meta-analysis was performed by including eight eligible published studies retrieved from PubMed (Medline), EMBASE and Google Scholar web search until December 2016. Individuals with AA genotype (AA vs CC: p = 0.001; OR = 2.602, 95% CI = 1.780 to 3.803) of LMP7 -145 C > A were found to have 2 folds higher risk of cancer than those with CC genotype. The recessive genetic model (AA vs AC + CC) also indicated that individuals with AA genotype have 2 folds higher cancer risk than AC and CC genotypes (p = 0.001; OR = 2.216, 95% CI = 1.525 to 3.221). Also, significant increased cancer risk was observed in Asians but not in Caucasians. No publication bias was observed during the analysis. Trial sequential analysis also strengthened our current findings. These results suggest that genetic variant LMP7–145 C > A has significant role in increasing cancer risk in overall and Asian population, and could be useful as a prognostic marker for early cancer predisposition.

Association and expression of the antigen-processing gene PSMB8, coding for low-molecular-mass protease 7, with vitiligo in North India: case-control study

BACKGROUND

Vitiligo is a multifactorial, autoimmune, depigmenting disorder of the skin where aberrant presentation of autoantigens may have a role.

OBJECTIVES

To study the association of two antigen-processing genes, PSMB8 and PSMB9, with vitiligo.

METHODS

In total 1320 cases of vitiligo (1050 generalized and 270 localized) and 752 healthy controls were studied for the PSMB9 exon 3 G/A single-nucleotide polymorphism (SNP), PSMB8 exon 2 C/A SNP and PSMB8 intron 6 G/T SNP at site 37 360 using polymerase chain reaction (PCR)-restriction fragment length polymorphism. Real-time PCR was used for transcriptional expression of PSMB8 and cytokines. Expression of ubiquitinated proteins and phosphorylated-p38 (P-p38) was studied by Western blotting.

RESULTS

Significant increases in PSMB8 exon 2 allele A (P < 2.07 × 10^-6 , odds ratio 1·93) and genotypes AA (P < 1.03 × 10^-6 , odds ratio 2·51) and AC (P < 1.29 × 10^-6 , odds ratio 1·63) were observed in patients with vitiligo. Interferon-γ stimulation induced lower expression of PSMB8 in peripheral blood mononuclear cells of cases compared with controls, suggesting impaired antigen processing, which was confirmed by accumulation of ubiquitinated proteins in both lesional and nonlesional skin of patients with vitiligo. Expression of proinflammatory cytokines - interleukin (IL)-6, IL-1β and IL-8 - was higher in the lesional skin. P-p38 expression was variable but correlated with the amount of ubiquitinated proteins in the lesional and nonlesional skin, suggesting that the inflammatory cytokine responses in lesional skin could be a result of both P-p38-dependent and -independent pathways.

CONCLUSIONS

The PSMB8 exon 2 SNP is significantly associated with vitiligo. Accumulation of ubiquitinated proteins in skin of cases of vitiligo suggests their aberrant processing, which may promote the development of the disease.

Association between LMP2/LMP7 genetic variability and cancer susceptibility, especially among Asians: evidence from a meta-analysis

Low molecular mass protein (LMP) gene performs a critical role in the foreign antigen processing machine via the major histocompatibility complex-I (MHC-I) complex CD8+ cytotoxic T lymphocytes (CTL) pathway. Recent studies have reported the association of LMP2-60 G>A (rs17587) and LMP7-145 C>A (rs2071543) polymorphisms with various types of cancers, but the outcomes remained inconsistent. To obtain a reliable conclusion, we summarized available data and conducted a meta-analysis involving a total of 19 published studies. Evidences were obtained from the PubMed, Google Scholar, Web of Science and Chinese National Knowledge Infrastructure (CNKI) databases. The results demonstrated that the rs17587 and rs2071543 polymorphisms were associated with an increased cancer risk in the recessive and homozygote models. Stratified analyses by ethnicity indicated a significant association only in Asian population. Furthermore, rs17587 showed a greater susceptibility to gynecological cancers, while rs2071543 increased the risk of gastrointestinal and gynecological cancers. Our results indicate that the LMP2 rs17587 and LMP7 rs2071543 polymorphisms may act as risk factors for cancer, especially for Asian populations. Additional larger-scale multicenter studies should be performed to validate our results.

PSMB8 as a Candidate Marker of Responsiveness to Preoperative Radiation Therapy in Rectal Cancer Patients

PURPOSE

The ability to predict individual responsiveness to cancer therapy is urgently needed. This is particularly true for patients with locally advanced rectal cancer (LARC) because a large proportion are resistant to preoperative chemoradiation therapy (CRT). In this study, we sought to identify markers that could predict response by comparing the gene expression profiles of the tumors of patients who received preoperative CRT.

METHODS AND MATERIALS

The basal gene expression profiles of tumors from 22 LARC patients who were responders (n=9) and nonresponders (n=13) to preoperative CRT were analyzed using RNA sequencing (RNA-Seq). To validate the RNA-Seq findings, real-time reverse transcriptase polymerase chain reaction (RT-PCR) was performed on tumor samples from an additional 40 LARC patients (n=20 responders; n=20 nonresponders). Candidate genes were stably overexpressed or knocked down in colorectal cancer (CRC) cell lines, and the effect on response to radiation was tested in vitro and also in vivo in a mouse xenograft model.

RESULTS

Eight differentially expressed (>16-fold) genes (B3GALT4, HSPA1B, KRBOX1, PPBP, PPP1R18, PSMB8, SLC39A7, and TAP2) associated with the preoperative CRT response were identified (P<.0005). Among these genes, real-time RT-PCR showed that PSMB8 and SLC39A7 were upregulated in the responsive group of the additional 40 LARC patients. In CRC cell lines, PSMB8 overexpression significantly reduced colony formation and increased the apoptosis-inducing molecules cleaved caspase-3 and cleaved PARP after 6-Gy irradiation. PSMB8 knockdown increased colony formation and decreased caspase-3 activation and cleaved PARP levels after irradiation. SLC39A7 overexpression had no significant effects on irradiated CSC cells. After irradiation of the xenografted mice, tumors that arose from CRC cell line HCT116 overexpressing PSMB8 grew more slowly than did those from HCT116 with vector alone.

CONCLUSION

These results suggest that PSMB8 is a predictive marker of preoperative radiosensitivity in LARC patients. Clinical validation in a larger cohort is now required.

Proteasome expression and activity in cancer and cancer stem cells

Proteasome is a multi-protein organelle that participates in cellular proteostasis by destroying damaged or short-lived proteins in an organized manner guided by the ubiquitination signal. By being in a central place in the cellular protein complement homeostasis, proteasome is involved in virtually all cell processes including decisions on cell survival or death, cell cycle, and differentiation. These processes are important also in cancer, and thus, the proteasome is an important regulator of carcinogenesis. Cancers include a variety of cells which, according to the cancer stem cell theory, descend from a small percentage of cancer stem cells, alternatively termed tumor-initiating cells. These cells constitute the subsets that have the ability to propagate the whole variety of cancer and repopulate tumors after cytostatic therapies. Proteasome plays a role in cellular processes in cancer stem cells, but it has been found to have a decreased function in them compared to the rest of cancer cells. This article will discuss the transcriptional regulation of proteasome sub-unit proteins in cancer and in particular cancer stem cells and the relationship of the proteasome with the pluripotency that is the defining characteristic of stem cells. Therapeutic opportunities that present from the understanding of the proteasome role will also be discussed.

Three Gene Signature for Predicting the Development of Hepatocellular Carcinoma in Chronically Infected Hepatitis C Virus Patients

Hepatitis C virus (HCV) is the leading cause of liver fibrosis and hepatocellular carcinoma (HCC). At present, there is no predictive biomarker for the patients at high risk of developing HCC. In this study, we examined the association between single-nucleotide polymorphisms (SNPs) in 3 innate immunity genes [2'-5'oligoadenylate synthetase 1 (OAS1) rs10774671, interleukin 28B (IL28B) rs12979860, and low molecular mass polypeptide 7 (LMP-7) at codon 49] besides cytomegalovirus (CMV) coinfection and susceptibility to HCC in genotype 4 (GT4) chronically infected Egyptian patients. SNPs were determined using restriction fragment length polymorphism analysis in DNA from HCC patients (n = 34) and compared with either controls (n = 70) or patients with early grades of liver fibrosis (n = 49). Our results demonstrated that patients bearing the genetic combination consisting of LMP-7 CA/AA [OR 4.75, 95% confidence interval (CI) 1.443-15.631, P = 0.007] and IL28B rs12979860 CT/TT (OR 6.00, 95% CI 1.603-22.455, P = 0.004) and positive for CMV viremia (OR 3.11, 95% CI 1.151-8.412, P = 0.02) were more likely to have HCC. However, OAS1 rs10774671 does not seem to contribute to the development of HCC. Binary regression analysis indicated that HCC risk significantly increases with the presence of each unfavorable genotype (LMP-7 CA/AA, IL28B rs12979860 CT/TT), when accompanied by the existence of CMV coinfection (probability of HCC risk is 0.8 for combined factors versus 0.14, 0.07, and 0.07 for individual factor IL28B, LMP-7, and CMV; respectively). These data suggest that the 2 SNPs and the coinfection in concert have potential in predicting the risk of HCC development in patients infected with HCV GT4.

The Immunoproteasome in oxidative stress, aging, and disease

The Immunoproteasome has traditionally been viewed primarily for its role in peptide production for antigen presentation by the major histocompatibility complex, which is critical for immunity. However, recent research has shown that the Immunoproteasome is also very important for the clearance of oxidatively damaged proteins in homeostasis, and especially during stress and disease. The importance of the Immunoproteasome in protein degradation has become more evident as diseases characterized by protein aggregates have also been linked to deficiencies of the Immunoproteasome. Additionally, there are now diseases defined by mutations or polymorphisms within Immunoproteasome-specific subunit genes, further suggesting its crucial role in cytokine signaling and protein homeostasis (or "proteostasis"). The purpose of this review is to highlight our growing understanding of the importance of the Immunoproteasome in the management of protein quality control, and the detrimental impact of its dysregulation during disease and aging.

MiR-451 suppresses cell proliferation and metastasis in A549 lung cancer cells

Recent study showed that inflammation was related to lung cancer. However, the exact cause of lung inflammation leading to carcinogenesis is unknown. MicroRNAs (miRNAs) are a group of endogenous non-coding small RNAs that regulate the activity of targeted mRNAs by inflammatory response in many diseases. MiR-451 was reported to relate to the development of lung cancer and metastasis of glioma. But the effect of miR-451 on cell proliferation, migration, and invasion of lung cancer is not really clear. In order to explore the molecular mechanism of the occurrence and development of lung cancer, we investigated the effect of human miR-451 on the proliferation, invasion, and metastasis in lung cancer cell line A549. The miR-451 expression construct was generated into pGenesil-1.1 and transfected into A549 cells. Results showed that the recombinant vectors were verified by sequencing. And miR-451 was over-expressed in A549 by real-time RT PCR. Furthermore, the proliferation, invasion, and metastasis of the cells in miR-451 group were inhibited significantly compared with those in control and A549 groups by MTT assay, Transwell invasion assay, and wound-healing assay. And the lung cancer metastasis factors (MMP-2, MMP-9, VEGF, and CXCR4) were decreased in miR-451 group by Western blot. Moreover, it was proved that inflammation-related gene-PSMB8 was a target for miR-451 by bioinformatics analysis and dual-luciferase reporter assay. And the protein expressions of PSMB8 and NOS2 were decreased in miR-451 group compared with those in control and A549 groups. Therefore, our findings indicated that miR-451 related to PSMB8/NOS2 inflammatory factors may suppress the development and migration of lung cancer, providing evidence for the role of miR-451 in lung cancer.

Association between LMP2 and LMP7 gene polymorphisms and the risk of gastric cancer: A case-control study

The integrality of low molecular weight protein (LMP)2/LMP7 function plays an important role in the processing of GC cell antigens. The purpose of the present hospital-based case-control study was to estimate the effect of polymorphisms in the LMP2 and LMP7 genes on the risk of GC. Polymerase chain reaction-restriction fragment length polymorphism analysis was used to distinguish the Arg to His substitution at codon 60 of LMP2 (LMP2-60) and the Gln to Lys substitution at codon 145 of LMP7 (LMP7-145) in 502 gastric cancer patients and 502 age and gender-matched cancer-free control individuals. The Lys allele of the LMP7-145 variant was more frequent in GC patients compared with control individuals [P=0.004; adjusted odds ratio (OR), 1.39; 95% confidence interval (CI), 1.11-1.74]. The Gln/Lys and Lys/Lys genotypes increased the risk of GC compared with the Gln/Gln genotype (P=0.049 and P=0.041, respectively; adjusted OR, 1.32 and 2.13, respectively; 95% CI, 1.00-1.73 and 1.03-4.39, respectively). Compared with the Gln/Gln genotype, the LMP7-145 Gln/Lys and Lys/Lys variants of the LMP7 gene were also associated with increased susceptibility to GC (P=0.017; adjusted OR, 1.38; 95% CI, 1.06-1.80). Haplotype analysis revealed that the LMP2 (Arg)-LMP7 (Lys) haplotype was associated with increased risk of GC (P=0.013, adjusted OR=1.34, 95% CI=1.06-1.70). Stratified analysis revealed that the association between the risk of GC and the variant genotypes of LMP7-145 was stronger in older individuals (>59 years), males and non-smokers. However, no association between the LMP2-60 polymorphism and the risk of GC was observed. The present results suggest that the LMP7-145 genetic variant contributes to increased susceptibility to GC, and the Lys allele is an independent risk factor for GC.

Evidence of positive selection at signal peptide region of interferon gamma

Interferon gamma (IFNG) is a major cytokine and plays crucial roles in pathogen clearance. About the course of evolution of IFNG, it has been reported that IFNG is being subjected to adaptive selection, which is proved at the level of gene. Neighbor-joining method was used to reconstruct the phylogenetic tree of all IFNG protein-coding sequences. The pair-wise computation of Ka/Ks between every exon homologs, branch-specific model, and site-specific model of the likelihood method were performed to detect positive selection of IFNG. We reported, for the first time, that the signal peptide region of IFNG is under significant positive selection, evolving faster than other parts. We provide evidence at the level of individual exon and individual amino acid site that IFNG is under adaptive evolution, which establishes the basis for further researches about IFNG.

Benefits of a continuous therapy for cancer patients with a novel adoptive cell therapy by cascade priming (CAPRI)

A growing body of evidence shows that immune cells are pivotal in the fight against cancer. First, association studies have identified immune-protective immune response genes against cancer. Second, the presence of immune cells in the respective malignant tumor correlated with a better prognosis for the patients. Third, adoptive cell therapy (ACT) showed, in recent reports, an efficient reduction or even cure for malignant tumors. The focus of this review is a novel in vitro ACT technique, using the patient’s cascade-primed immune cells. The cascade-priming procedure stimulates APCs from the peripheral blood. Stimulated APCs digest and present tumor material better and differentiate naive cytotoxic T-lymphocyte effector cells against the patient’s cancer. The principle and the impressive results of the cascade-primed immune cell treatment in patient case series is compared with the ACT concepts of lymphokine-activated killer, macrophage-activated killer, macrophage-activated killer-dendritic cell, cytokine-induced killer and tumor-infiltrating lymphocyte methods.

Genetics of proteasome diseases

The proteasome is a large, multiple subunit complex that is capable of degrading most intracellular proteins. Polymorphisms in proteasome subunits are associated with cardiovascular diseases, diabetes, neurological diseases, and cancer. One polymorphism in the proteasome gene PSMA6 (-8C/G) is associated with three different diseases: type 2 diabetes, myocardial infarction, and coronary artery disease. One type of proteasome, the immunoproteasome, which contains inducible catalytic subunits, is adapted to generate peptides for antigen presentation. It has recently been shown that mutations and polymorphisms in the immunoproteasome catalytic subunit PSMB8 are associated with several inflammatory and autoinflammatory diseases including Nakajo-Nishimura syndrome, CANDLE syndrome, and intestinal M. tuberculosis infection. This comprehensive review describes the disease-related polymorphisms in proteasome genes associated with human diseases and the physiological modulation of proteasome function by these polymorphisms. Given the large number of subunits and the central importance of the proteasome in human physiology as well as the fast pace of detection of proteasome polymorphisms associated with human diseases, it is likely that other polymorphisms in proteasome genes associated with diseases will be detected in the near future. While disease-associated polymorphisms are now readily discovered, the challenge will be to use this genetic information for clinical benefit.

GSK-3β signaling determines autophagy activation in the breast tumor cell line MCF7 and inclusion formation in the non-tumor cell line MCF10A in response to proteasome inhibition

The ubiquitin–proteasome system and the autophagy–lysosome pathway are the two main mechanisms for eukaryotic intracellular protein degradation. Proteasome inhibitors are used for the treatment of some types of cancer, whereas autophagy seems to have a dual role in tumor cell survival and death. However, the relationship between both pathways has not been extensively studied in tumor cells. We have investigated both proteolytic systems in the human epithelial breast non-tumor cell line MCF10A and in the human epithelial breast tumor cell line MCF7. In basal condition, tumor cells showed a lower proteasome function but a higher autophagy activity when compared with MCF10A cells. Importantly, proteasome inhibition (PI) leads to different responses in both cell types. Tumor cells showed a dose-dependent glycogen synthase kinase-3 (GSK-3)β inhibition, a huge increase in the expression of the transcription factor CHOP and an active processing of caspase-8. By contrast, MCF10A cells fully activated GSK-3β and showed a lower expression of both CHOP and processed caspase-8. These molecular differences were reflected in a dose-dependent autophagy activation and cell death in tumor cells, while non-tumor cells exhibited the formation of inclusion bodies and a decrease in the cell death rate. Importantly, the behavior of the MCF7 cells can be reproduced in MCF10A cells when GSK-3β and the proteasome were simultaneously inhibited. Under this situation, MCF10A cells strongly activated autophagy, showing minimal inclusion bodies, increased CHOP expression and cell death rate. These findings support GSK-3β signaling as a key mechanism in regulating autophagy activation or inclusion formation in human tumor or non-tumor breast cells, respectively, which may shed new light on breast cancer control.