MHC Class I-related Chain A Research Articles

Differential Expression of Granulysin, MHC Class I-Related Chain A, and Perforin in Serum and Peritoneal Fluid: Immune Dysregulation in Endometriosis-Related Infertility

ABSTRACT Introduction Endometriosis is a chronic inflammatory disease characterized by endometrial-like tissue outside the uterus. Molecules linked to natural killer (NK) and cytotoxic T cells, including granulysin (GNLY), MHC class I-related chain A (MICA), and perforin (PRF1) support immune surveillance, though their roles in endometriosis remain unclear. This study investigates the association of these molecules with clinical parameters in infertile women with endometriosis. Methods Eighty-seven infertile women undergoing diagnostic laparoscopy were included: 44 with endometriosis and 43 with benign gynecologic disorders. Serum and peritoneal molecules were measured using ELISA. Statistical analyses compared groups and correlated immune markers with clinical parameters. Results Endometriosis patients displayed significantly higher PRF1 levels in serum (p = .038) and peritoneal fluid (p = .002), particularly in late-stage disease. Serum and peritoneal PRF1 levels correlated positively with the rASRM adhesion scores. Elevated serum PRF1 was observed in ovarian endometrioma (p = .021). Peritoneal MICA was higher in late-stage endometriosis (p = .013). Serum MICA was elevated in the follicular phase compared to the luteal phase (p = .008). Conclusion Elevated PRF1 and MICA levels were associated with endometriosis severity, indicating their potential as biomarkers. Future studies should validate this finding and explore its therapeutic role in endometriosis.

Proteasome inhibitors FHND6091 enhance the ability of NK cells to kill tumor cells through multiple mechanisms

The immune system has a strong connection to tumors. When a tumor cell is recognized as an abnormal cell by the immune system, the immune system may initiate an immune response to kill the tumor cell. In this study, RNA sequencing was performed on multiple myeloma (MM) cells treated with the proteasome inhibitor FHND6091. The transcriptional changes induced by FHND6091 in RPMI8226 cells aligned notably with immune response activation and results indicated upregulation of cGAS-STING pathway-related genes in the FHND6091-treated group. In vivo and in vitro experiments had demonstrated that FHND6091 stimulated the immunoreaction of MM cells via activation of the cyclic guanosine monophosphate-adenosine synthase/stimulator of interferon genes (cGAS-STING) pathway. This activation resulted in the generation of type-I interferons and the mobilization of natural killer (NK) cells. Notably, FHND6091 upregulated the levels of calreticulin and the protein ligands UL16-binding protein 2/5/6, MHC class I chain-related A (MICA), and MICB on the surface of MM cells. Subsequently, upon engaging with the surface activation receptors of NK cells, these ligands triggered NK cell activation, leading to the subsequent elimination of tumor cells. Thus, our findings elucidated the mechanism whereby FHND6091 exerted its immunotherapeutic activity as a STING agonist, enhancing the killing ability of NK cells against tumor cells.

Impact of MICA 3'UTR allelic variability on miRNA binding prediction, a bioinformatic approach.

MicroRNAs (miRNAs) are small non-coding RNAs that participate as powerful genetic regulators. MiRNAs can interfere with cellular processes by interacting with a broad spectrum of target genes under physiological and pathological states, including cancer development and progression. Major histocompatibility complex major histocompatibility complex class I-related chain A (MICA) belongs to a family of proteins that bind the natural-killer group 2, member D (NKG2D) receptor on Natural Killer cells and other cytotoxic lymphocytes. MICA plays a crucial role in the host's innate immune response to several disease settings, including cancer. MICA harbors various single nucleotide polymorphisms (SNPs) located in its 3'-untranslated region (3'UTR), a characteristic that increases the complexity of MICA regulation, favoring its post-transcriptional modulation by miRNAs under physiological and pathological conditions. Here, we conducted an in-depth analysis of MICA 3'UTR sequences according to each MICA allele described to date using NCBI database. We also systematically evaluated interactions between miRNAs and their putative targets on MICA 3'UTR containing SNPs using in silico analysis. Our in silico results showed that MICA SNPs rs9266829, rs 1880, and rs9266825, located in the target sequence of miRNAs hsa-miR-106a-5p, hsa-miR-17-5p, hsa-miR-20a-5p, hsa-miR-20b-5p, hsa-miR-93, hsa-miR-1207.5p, and hsa-miR-711 could modify the binding free energy between -8.62 and -18.14kcal/mol, which may affect the regulation of MICA expression. We believe that our results may provide a starting point for further exploration of miRNA regulatory effects depending on MICA allelic variability; they may also be a guide to conduct miRNA in silico analysis for other highly polymorphic genes.

Association of MICA Gene Polymorphism in Opisthorchis viverrini-Induced Periductal Fibrosis in Northeastern Thais.

Chronic Opisthorchis viverrini (OV) infection is the cause of advanced periductal fibrosis (APF), subsequently leading to cholangiocarcinoma (CCA). Natural killer (NK) cells can kill hepatic stellate cells (HSCs), the initiating cells for fibrosis formation, by using the interaction between the natural killer group 2 member D (NKG2D) receptor and its ligand on the HSCs. This can inhibit the fibrosis formation. Major histocompatibility complex class I chain-related A (MICA) is the ligand of the NKG2D receptor and has highly polymorphic characteristics that are involved in NKG2D binding and NK cell activation. This study aimed to investigate the polymorphism of MICA in OV-induced fibrosis. MICA typing was performed by polymerase chain reaction- sequence specific primer (PCR-SSP) and sequencing in two groups: OV infection without fibrosis (N = 99) and with fibrosis (N = 290). Six alleles were identified and the MICA*010 allele had the highest frequency in both groups. The MICA*00201-02 allele was a protective factor for fibrosis (OR= 0.508, 95%CI= 0.34-0.76, Pc <0.05), while the MICA*019 allele was suggested to be a risk allele for fibrosis (OR=1.95, 95%CI=1.25-3.03, Pc<0.005). In addition, two motifs, glycine (G) at position 14 and glutamine (Q) at position 251, were negatively associated with fibrosis (G14: OR=0.508, 95%CI=0.34-0.76, Pc <0.05 and Q251: OR=0.586, 95%CI=0.41-0.84, Pc <0.05). Moreover, the distribution of the MICA-129 genotype also showed the protective genotype (Pc<0.05, OR=0.319, 95%CI= 0.12-0.54) for fibrosis. The MICA*00201-02 allele encoded all these motifs, and this suggested that it might lead to strong NK cell activation to kill HSCs, subsequently preventing fibrosis formation. This study described initial evidence suggesting that the polymorphism of the MICA gene might be a marker for OV-derived periductal fibrosis.

Correlation of Epstein-Barr virus copy numbers, MICA expression and rs2596542 variant in nasopharyngeal carcinoma tumour

Major histocompatibility complex class I chain-related A (MICA) is a tumour antigen that is greatly expressed on the surfaces of human malignancies and infection cells, which trigger attachment to immune cells. Although many studies have investigated the role of the MICA rs2596542 variant involved in high risk of hepatocellular carcinoma (HCC), the expression regulation of rs2596542 MICA in nasopharyngeal carcinoma (NPC) susceptibility with the Epstein-Barr virus (EBV) is still ambiguous. Therefore, this study was conducted to elucidate the association of rs2596542C/T and EBV load to MICA expression in NPC tissues. A total of 70 tumour tissues from NPC patients were enrolled in the current study. The genetic variant of rs2596542 was identified by Real-time PCR genotyping, and MICA protein expression was quantified by immunohistochemistry staining. A significant difference was observed in the expression of MICA regarding EBV copy numbers (p&lt;0.01). High expression of MICA presented a considerably lower EBV status. In addition, higher expression of homologous MICA rs2596542 CC was significantly associated with a lower EBV load (p&lt;0.001) thus suggesting a protective role of allele C against the infection of EBV. In summary, rs2596542 MICA plays an important role in the immune response preventing the EBV among NPC patients as well as developing a new predictive biomarker for virus susceptibility to cancers.

Successful Identification of a Novel Therapeutic Compound for Hepatocellular Carcinoma Through Screening of ADAM9 Inhibitors.

MHC-class I-related chain A (MICA) functions as a ligand for natural killer group D, an activating receptor on natural killer (NK) cells, and its expression correlates with the carcinogenesis and progression of hepatocellular carcinoma (HCC). Although membranous MICA (mMICA) activates NK cells, soluble forms of MICA (sMICA), shed by cleaving enzymes, such as A disintegrin and metalloprotease (ADAM) 9, suppress NK cells. Therefore, the prevention of MICA shedding through the inhibition of ADAM9 has the potential to activate cancer immunity. Although we have discovered several ADAM inhibitors, many did not sufficiently activate NK cells without being cytotoxic, and, thus, new ADAM9 inhibitor candidates are needed. To identify possible compounds for drug development, chemical library screening (a total of 741 compounds) was conducted using a fluorescence assay. Compounds with reduced fluorescence intensity were used as hit compounds in a subsequent analysis. Their impact on sMICA and mMICA in HCC cell lines was assessed using ELISA and flow cytometry, respectively. The cytotoxicity of NK cells was also evaluated by co-culturing NK cells with HCC cells. CCL347, a symmetrical compound with five benzene rings, was identified as a hit compound. CCL347 significantly reduced sMICA levels in the culture medium supernatant with negligible cytotoxicity. Although mMICA was also reduced, CCL347 successfully enhanced NK cell cytotoxicity in co-cultures of NK cells and HCC cells. CCL347 has potential as a novel therapeutic drug for HCC.

Alopecia Areata: A Review of the Role of Oxidative Stress, Possible Biomarkers, and Potential Novel Therapeutic Approaches.

Alopecia areata (AA) is a dermatological condition characterized by non-scarring hair loss. Exact etiopathogenesis of AA is still unknown although it is known that several factors contribute to the collapse of the hair-follicle (HF)-immune-privileged (IP) site. Oxidative stress (OS) plays an important role in skin diseases. The aim of this review was to clarify the role of OS in AA pathogenesis and diagnosis, and to discuss potential treatment options. Oxidative-stress markers are altered in serum and skin samples of patients with AA, confirming a general pro-oxidative status in patients with AA. OS induces MHC class I chain-related A (MICA) expression in HF keratinocytes that activates the receptor NKG2D, expressed in NK cells and CD8+ T cytotoxic cells leading to destabilization of the HF immune-privileged site through the production of IFN-γ that stimulates JAK1 and JAK2 pathways. OS also activates the KEAP1-NRF2 pathway, an antioxidant system that contributes to skin homeostasis. In addition, a decrease of ATG5 and LC3B in the hair matrix and an increase in p62 levels indicates a reduction of intrafollicular autophagy during the evolution of AA. Potential biomarkers of OS in AA could be: malondialdehyde (MDA), advanced glycation end-products (AGEs), and ischemic-modified albumin (IMA). JAK inhibitors are the new frontier in treatment of AA and the use of nutraceuticals that modulate the OS balance, in combination with standard treatments, represent promising therapeutic tools.

Biosensors Based on Ion-Sensitive Field-Effect Transistors for HLA and MICA Antibody Detection in Kidney Transplantation.

This work demonstrates the ability of the Ion-Sensitive Field-Effect Transistor (ISFET)-based immunosensor to detect antibodies against the human leukocyte antigen (HLA) and the major histocompatibility complex class-I-related chain A (MICA). The sensing membrane of the ISFET devices was modified and functionalized using an APTES-GA strategy. Surface properties, including wettability, surface thickness, and surface topology, were assessed in each module of the modification process. The optimal concentrations of HLA and MICA proteins for the immobilization were 10 and 50 μg/mL. The dose-response curve showed a detection range of 1.98–40 µg/mL for anti-HLA and 5.17–40 µg/mL for anti-MICA. The analytical precision (%CV) was found to be 10.69% and 8.92% for anti-HLA and -MICA, respectively. Moreover, the electrical signal obtained from the irrelevant antibody was considerably different from that of the specific antibodies, indicating the specific binding of the relevant antibodies without noise interference. The sensitivity and specificity in the experimental setting were established for both antibodies (anti-HLA: sensitivity = 80.00%, specificity = 86.36%; anti-MICA: sensitivity = 86.67%, specificity = 88.89%). Our data reveal the potential of applying the ISFET-based immunosensor to the detection of relevant anti-HLA and -MICA antibodies, especially in the field of kidney transplantation.

Posttransplant-Alloantibodies Against MICA Antigens Associated With Decreased Long-Term Allograft Survival of Kidney Transplant Recipients

Previous evidence showed that antibodies against major histocompatibility complex class I-related chain A (MICA) could lead to antibody-mediated rejection in kidney transplantation in case where the patients had no alloantibodies against HLA. However, the effects of posttransplant anti-MICA antibodies on long-term renal allograft survival and function remained unsettled. We tested the posttransplant anti-MICA antibodies in 150 kidney transplant patients. The aim of this study was to compare the long-term graft survival and function between patients who were MICA positive and those who were negative. The posttransplant serum samples from 150 patients receiving kidney transplantation in our center from 2012 to 2013 were tested for MICA antibodies and HLA antibodies by Luminex single antigen array technology. Graft survival and function were followed up for a mean time of 74.2 months. The research was conducted in accordance with the Helsinki Congress and the Declaration of Istanbul. Of the 150 patients, 38 (25.3%) were sensitized against MICA after transplantation. The anti-MICA antibodies-positive (anti-MICA+) group had a worse long-term renal allograft survival than that of anti-MICA-negative (anti-MICA-) group (P = .029), even when stratified by posttransplant HLA sensitization status or donor source. Anti-MICA antibodies also had a detrimental impact on renal allograft function, but only at 1 year posttransplantation (estimated glomerular filtration rates at 1 year: anti-MICA+ 66.6 mL/min/1.73 m2 vs anti-MICA- 78.7 mL/min/1.73 m2; P = .023). Posttransplant anti-MICA antibodies were associated with decreased long-term renal allograft survival and short-term renal allograft function.

Major Histocompatibility Complex Class I Chain-Related α (MICA) STR Polymorphisms in COVID-19 Patients.

The SARS-CoV-2 disease presents different phenotypes of severity. Comorbidities, age, and being overweight are well established risk factors for severe disease. However, innate immunity plays a key role in the early control of viral infections and may condition the gravity of COVID-19. Natural Killer (NK) cells are part of innate immunity and are important in the control of virus infection by killing infected cells and participating in the development of adaptive immunity. Therefore, we studied the short tandem repeat (STR) transmembrane polymorphisms of the major histocompatibility complex class I chain-related A (MICA), an NKG2D ligand that induces activation of NK cells, among other cells. We compared the alleles and genotypes of MICA in COVID-19 patients versus healthy controls and analyzed their relation to disease severity. Our results indicate that the MICA*A9 allele is related to infection as well as to symptomatic disease but not to severe disease. The MICA*A9 allele may be a risk factor for SARS-CoV-2 infection and symptomatic disease.

MICA and KIR: Immunogenetic Factors Influencing Left Ventricular Systolic Dysfunction and Digestive Clinical Form of Chronic Chagas Disease.

Tissue damage observed in the clinical forms of chronic symptomatic Chagas disease seems to have a close relationship with the intensity of the inflammatory process. The objective of this study was to investigate whether the MICA (MHC class I-related chain A) and KIR (killer cell immunoglobulin-like receptors) polymorphisms are associated with the cardiac and digestive clinical forms of chronic Chagas disease. Possible influence of these genes polymorphisms on the left ventricular systolic dysfunction (LVSD) in patients with chronic Chagas heart disease was also evaluated. This study enrolled 185 patients with positive serology for Trypanosoma cruzi classified according to the clinical form of the disease: cardiac (n=107) and digestive (n=78). Subsequently, patients with the cardiac form of the disease were sub-classified as with LVSD (n=52) and without LVSD (n=55). A control group was formed of 110 healthy individuals. Genotyping was performed by polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSOP). Statistical analyzes were carried out using the Chi-square test and odds ratio with 95% confidence interval was also calculated to evaluate the risk association. MICA-129 allele with high affinity for the NKG2D receptor was associated to the LVSD in patients with CCHD. The haplotype MICA*008~HLA-C*06 and the KIR2DS2-/KIR2DL2-/KIR2DL3+/C1+ combination were associated to the digestive clinical form of the disease. Our data showed that the MICA and KIR polymorphisms may exert a role in the LVSD of cardiac patients, and in digestive form of Chagas disease.

Abstract 2740: Effect of pancreatic cancer cell derived extracellularvesicles on the tumor microenvironment

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is one amongst the most lethal malignancies, with a 5 year survival rate of &amp;lt;10%.While the tumor microenvironment in PDAC is highly immunosuppressive, little is known about the mechanisms of immune invasion leading to rapid tumor progression. Hence, in-depth exploration of early cellular and molecular drivers of PDAC is desirable for early and precise diagnosis and to identify new biological targets for developing new therapies. Extracellular vesicles (EVs) are nanometer sized particles that are shed by most tissues/organs and are known to be important mediators of intercellular signaling and molecular transfer. We hypothesized that pancreatic cancer derived EVs may play an important role in mediating the interactions among the tumor and surrounding microenvironment (TME). Given that tumor-associated macrophages (TAMs) are integral components of the TME that can promote tumor progression, tumor invasion, and intravasation to other parts of the body, this study is focused on investigating the role of PDAC derived EVs in macrophages polarization, which in turn would impact tumor cell proliferation and invasion. Results: EVs were isolated from 6 pancreatic cancer (PaCa) and 2 normal established pancreatic epithelial cell lines. EVs were characterized using nanoparticle tracking (NTA) and immunoblot analysis. LC-MS/MS based shotgun proteomics analyses of EVs revealed that PaCa cell line derived EVs were significantly enriched in potentially immunomodulatory proteins such as S100 calcium-binding protein A4 (S100A4) and human leukocyte antigen-B (HLA-B). However, PaCa cell EVs had significantly less MHC-class-I-related chain A (MICA), a protein important for proper human leukocyte antigen (HLA) function, as compared to normal pancreatic epithelial cell derived EVs. These data suggest that PaCa derived EVs may influence immunomodulation and macrophage function within the tumor microenvironment thereby strengthening our hypothesis. Further experimental studies aimed at delineating the precise mechanism of action of EVs in macrophage polarization is ongoing. Conclusions: Our finding suggests significant difference among the molecular composition of PaCa derived cargos as compared to and normal cells derived EVs that could be useful in furthering our understanding about pancreatic cancer etiology. Furthermore, the novel insights obtained from these studies may augment the development of biomarkers that can be used for early detection of the disease and improved therapeutics to improve clinical outcomes. Citation Format: Baldev Singh, Charles Hinzman, Edina Wang, Anton Iliuk, Jose Trevino, Keith Unger, Partha Banerjee, Amrita K. Cheema. Effect of pancreatic cancer cell derived extracellularvesicles on the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2740.

The human cytomegalovirus protein UL147A downregulates the most prevalent MICA allele: MICA*008, to evade NK cell-mediated killing.

Natural killer (NK) cells are innate immune lymphocytes capable of killing target cells without prior sensitization. One pivotal activating NK receptor is NKG2D, which binds a family of eight ligands, including the major histocompatibility complex (MHC) class I-related chain A (MICA). Human cytomegalovirus (HCMV) is a ubiquitous betaherpesvirus causing morbidity and mortality in immunosuppressed patients and congenitally infected infants. HCMV encodes multiple antagonists of NK cell activation, including many mechanisms targeting MICA. However, only one of these mechanisms, the HCMV protein US9, counters the most prevalent MICA allele, MICA*008. Here, we discover that a hitherto uncharacterized HCMV protein, UL147A, specifically downregulates MICA*008. UL147A primarily induces MICA*008 maturation arrest, and additionally targets it to proteasomal degradation, acting additively with US9 during HCMV infection. Thus, UL147A hinders NKG2D-mediated elimination of HCMV-infected cells by NK cells. Mechanistic analyses disclose that the non-canonical GPI anchoring pathway of immature MICA*008 constitutes the determinant of UL147A specificity for this MICA allele. These findings advance our understanding of the complex and rapidly evolving HCMV immune evasion mechanisms, which may facilitate the development of antiviral drugs and vaccines.

Increased Concentrations of Circulating Soluble MHC Class I-Related Chain A (sMICA) and sMICB and Modulation of Plasma Membrane MICA Expression: Potential Mechanisms and Correlation With Natural Killer Cell Activity in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a severe autoimmune disease of unknown etiology. The major histocompatibility complex (MHC) class I-related chain A (MICA) and B (MICB) are stress-inducible cell surface molecules. MICA and MICB label malfunctioning cells for their recognition by cytotoxic lymphocytes such as natural killer (NK) cells. Alterations in this recognition have been found in SLE. MICA/MICB can be shed from the cell surface, subsequently acting either as a soluble decoy receptor (sMICA/sMICB) or in CD4+ T-cell expansion. Conversely, NK cells are frequently defective in SLE and lower NK cell numbers have been reported in patients with active SLE. However, these cells are also thought to exert regulatory functions and to prevent autoimmunity. We therefore investigated whether, and how, plasma membrane and soluble MICA/B are modulated in SLE and whether they influence NK cell activity, in order to better understand how MICA/B may participate in disease development. We report significantly elevated concentrations of circulating sMICA/B in SLE patients compared with healthy individuals or a control patient group. In SLE patients, sMICA concentrations were significantly higher in patients positive for anti-SSB and anti-RNP autoantibodies. In order to study the mechanism and the potential source of sMICA, we analyzed circulating sMICA concentration in Behcet patients before and after interferon (IFN)-α therapy: no modulation was observed, suggesting that IFN-α is not intrinsically crucial for sMICA release in vivo. We also show that monocytes and neutrophils stimulated in vitro with cytokines or extracellular chromatin up-regulate plasma membrane MICA expression, without releasing sMICA. Importantly, in peripheral blood mononuclear cells from healthy individuals stimulated in vitro by cell-free chromatin, NK cells up-regulate CD69 and CD107 in a monocyte-dependent manner and at least partly via MICA-NKG2D interaction, whereas NK cells were exhausted in SLE patients. In conclusion, sMICA concentrations are elevated in SLE patients, whereas plasma membrane MICA is up-regulated in response to some lupus stimuli and triggers NK cell activation. Those results suggest the requirement for a tight control in vivo and highlight the complex role of the MICA/sMICA system in SLE.

MICA A5.1 homozygous genotype is associated with a risk for early-onset oral cancer

ObjectivesGenetic predisposition is reportedly involved in early-onset oral cancer, although the genetic basis of this cancer remains unclear. The major histocompatibility complex class I-related chain A (MICA) plays a crucial role in eliminating malignant tumors by activating NKG2D, the natural killer (NK) receptor. MICA polymorphism might affect its binding to NKG2D. We aimed to find whether MICA gene microsatellite polymorphism is involved in the risk of oral squamous cell carcinoma (OSCC) development in a Japanese population. Materials and methodsWe recruited 386 patients with OSCC and 103 healthy controls. Genomic DNA was analyzed by PCR for microsatellite repeat polymorphism in the transmembrane region of the MICA gene. The groups were compared for the prevalence of various alleles and their association with disease prognosis and survival. ResultsWe found that adolescents and young adults (AYA) with OSCC were more likely to have the MICA A5.1 homozygous genotype than healthy controls (P = 0.0001), but their survival rate was higher than with other MICA genotypes (P = 0.0185). ConclusionThese results suggest that cancer’s immune escape is facilitated by MICA’s failure to activate the NK cells. MICA A5.1 homozygosity plays a role in individual susceptibility to OSCC, increasing the risk of early‐onset oral cancer. However, such patients have a better prognosis than those with other MICA genotypes.

Core 2 β1,6-N-acetylglucosaminyltransferases accelerate the escape of choriocarcinoma from natural killer cell immunity

Hyperglycosylated human chorionic gonadotropin (H-hCG) is secreted from choriocarcinoma and contains a core2 O-glycan formed by core2 β1,6-N-acetylglucosaminyl transferase (C2GnT). Choriocarcinoma is considered immunogenic as it is gestational and contains paternal chromosomal components. Here we examined the function of C2GnT in the evasion of choriocarcinoma cells from natural killer (NK) cell-mediating killing. We determined that C2GnT is highly expressed in malignant gestational trophoblastic neoplasms. C2GnT KO downregulates core2 O-glycan expression in choriocarcinoma cells, which are more efficiently killed by NK cells than control cells. C2GnT KO cell containing tumor necrosis factor-related apoptosis inducing ligand have lower viability than control cells. Additionally, poly-N-acetyllactosamine in core2 branched oligosaccharides on MHC class I-related chain A (MICA) and mucin1 (MUC1) is significantly reduced in C2GnT KO cells. Meanwhile, the cumulative survival rate of nude mice inoculated with C2GnT KO tumors was higher than that of the control group. These findings suggest that choriocarcinoma cells may escape NK cell-mediated killing via glycosylation of MICA and MUC1.

Major Histocompatibility Complex Class I-Related Chain A Alleles and Histology of Nonalcoholic Fatty Liver Disease.

Major histocompatibility complex class I‐related chain A (MICA) is a highly polymorphic gene that modulates immune surveillance by binding to its receptor on natural killer cells, and its genetic polymorphisms have been associated with chronic immune‐mediated diseases. The progressive form of nonalcoholic fatty liver disease (NAFLD), nonalcoholic steatohepatitis (NASH), is characterized by accumulation of fat and inflammatory cells in the hepatic parenchyma, potentially leading to liver cell injury and fibrosis. To date, there are no data describing the potential role of MICA in the pathogenesis of NAFLD. Therefore, our aim was to assess the association between MICA polymorphism and NASH and its histologic features. A total of 134 subjects were included. DNA from patients with biopsy‐proven NAFLD were genotyped using polymerase chain reaction–sequence‐specific oligonucleotide for MICA alleles. Liver biopsies were assessed for histologic diagnosis of NASH and specific pathologic features, including stage of fibrosis and grade of inflammation. Multivariate analysis was performed to draw associations between MICA alleles and the different variables; P ≤ 0.05 was considered significant. Univariate analysis showed that MICA*011 (odds ratio [OR], 7.14; 95% confidence interval [CI], 1.24‐41.0; P = 0.04) was associated with a higher risk for histologic NASH. Multivariate analysis showed that MICA*002 was independently associated with a lower risk for focal hepatocyte necrosis (OR, 0.24; 95% CI, 0.08‐0.74; P = 0.013) and advanced fibrosis (OR, 0.11; 95% CI, 0.02‐0.70; P = 0.019). MICA*017 was independently associated with a higher risk for lymphocyte‐mediated inflammation (OR, 5.12; 95% CI, 1.12‐23.5; P = 0.035). Conclusion: MICA alleles may be associated with NASH and its histologic features of inflammation and fibrosis. Additional research is required to investigate the potential role of MICA in increased risk or protection against NAFLD.

Celecoxib upregulates ULBP-1 expression in lung cancer cells via the JNK/PI3K signaling pathway and increases susceptibility to natural killer cell cytotoxicity.

Lung cancer has the highest cancer mortality rate in the world, and effective therapies are still required. Cyclooxygenase-2 (COX-2) is highly expressed in numerous types of cancer, and is therefore considered a possible target of cancer treatment. Celecoxib, a selective COX-2 inhibitor, has binding pockets that interact with COX-2 and disrupt its enzymatic activities. In addition, celecoxib is able to affect cellular functions in a COX-2-independent manner. The present study aimed to investigate if celecoxib affected natural killer (NK) cell receptors and susceptibility to NK cell toxicity. For this purpose, PCR, immunoblotting, flow cytometry analysis and NK cell cytotoxicity assays were performed. The present study revealed that sublethal concentrations of celecoxib increased the expression levels of UL16-binding protein 1 (ULBP-1), a natural-killer group 2 member D (NKG2D) ligand, in lung cancer A549 and H460 cell lines. ULBP-1 mRNA and protein expression was induced in a dose- and time-dependent manner after celecoxib treatment. Expression levels of other NKG2D ligands, such as ULBP-2, ULBP-3, MHC class I-related chain A (MICA) and MICB did not change considerably compared to ULBP-1 in response to celecoxib treatment. Fluorescence microscopic images revealed abundant ULBP-1 in the cytoplasm after celecoxib treatment. Both JNK and PI3K may be involved in the induction of ULBP-1 expression after celecoxib treatment in A549 and H460 cells. In a NK cytotoxicity assay, celecoxib increased the sensitivity to NK cell-mediated cytotoxicity via interaction with ULBP-1 in lung cancer cells. Overall, the present results demonstrated that celecoxib treatment induced ULBP-1 expression in lung cancer cells, thereby increasing their susceptibility to NK cell cytotoxicity. These results suggest that the effects of conventional anticancer therapy may potentially be enhanced by using celecoxib, which targets COX-2, to enhance the sensitivity of lung cancer cells to NK cell-mediated cytotoxicity.

Leukotriene receptor antagonists enhance HCC treatment efficacy by inhibiting ADAMs and suppressing MICA shedding

In our previous genome-wide association study, we demonstrated the association between MHC class I-related chain A (MICA) and hepatocellular carcinoma (HCC) development in patients with chronic hepatitis C. Increasing membrane-bound MICA (mMICA) in cancer cells by reducing MICA sheddases facilitates natural killer (NK) cell-mediated cytotoxicity. Our recent study clarified that A disintegrin and metalloproteases (ADAM), including ADAM9, are MICA sheddases in HCC, and that the suppression of ADAMs increases mMICA, demonstrating the rationality of mMICA-NK targeted therapy. Furthermore, we showed that regorafenib suppresses ADAM9 transcriptionally and translationally. A library of FDA-approved drugs was screened for more efficient inhibitors of ADAM9. Flow cytometry evaluation of the expression of mMICA after treatment with various candidate drugs identified leukotriene receptor antagonists as potential ADAM9 inhibitors. Furthermore, leukotriene receptor antagonists alone or in combination with regorafenib upregulated mMICA, which was in turn downregulated by leukotriene C4 and D4 via ADAM9 function. Our study demonstrates that leukotriene receptor antagonists could be developed as novel drugs for immunological control and suppression of ADAM9 in HCC. Further, leukotriene receptor antagonists should be explored as combination therapy partners with conventional multi-kinase inhibitors for developing therapeutic strategies with enhanced efficacies for HCC management and treatment.

MHC Class I related chain A (MICA), Human Leukocyte Antigen (HLA)-DRB1, HLA-DQB1 genotypes in Turkish patients with ulcerative colitis

Abstract Objectives We aimed to determine Human Leukocyte Antigen (HLA)-DRB1, DQB1, and MHC Class I related chain A (MICA) genotypes in patients with ulcerative colitis. Methods HLA-DRB1, HLA-DQB1, MICA genotyping of patient (n:85) and controls (n:100) were performed by PCR-SSO Luminex (One Lambda genotyping kit). Results We found significantly higher DRB1*01 (p:0.022, OR:0.23, CI:0.06–0.8) and MICA*0002/20/55 (p:0.03, OR:0.53, CI:0.29–0.93) alleles in control group whereas DRB1*14 (p:0.04, OR:2.25, CI:1–5.08), DRB1*15 (p:&lt;0.0001, OR:4.54, CI:2.09–9.88) and MICA*0004 (p:0.01, OR:2.84, CI:1.2–6.7) alleles were higher in patient group. Conclusions The present study will inform the MICA and HLA genotypes about the protective (DRB1*01, MICA*0002/20/55) or susceptible (DRB1*14, DRB1*15, MICA*0004) alleles of the disease and helps the literature on Turkish patients with ulcerative colitis.