CircARAP2 controls sMICA-induced NK cell desensitization by erasing CTCF/PRC2-induced suppression in early endosome marker RAB5A.

Natural killer cells (NK) are the "professional killer" of tumors and play a crucial role in anti-tumor immunotherapy. NK cell desensitization is a key mechanism of tumor immune escape. Dysregulated NKG2D-NKG2DL signaling is a primary driver of this desensitization process. However, the factors that regulate NK cell desensitization remain largely uncharacterized. Here, we present the first report that circular RNA circARAP2 (hsa_circ_0069396) is involved in the soluble MICA (sMICA)-induced NKG2D endocytosis in the NK cell desensitization model. CircARAP2 was upregulated during NK cell desensitization and the loss of circARAP2 alleviated NKG2D endocytosis and NK cell desensitization. Using Chromatin isolation by RNA purification (ChIRP) and RNA pull-down approaches, we identified that RAB5A, a molecular marker of early endosomes, was its downstream target. Notably, transcription factor CTCF was an intermediate functional partner of circARAP2. Mechanistically, we discovered that circARAP2 interacted with CTCF and inhibited the recruitment of CTCF-Polycomb Repressive Complex 2 (PRC2) to the promoter region of RAB5A, thereby erasing histone H3K27 and H3K9 methylation suppression to enhance RAB5A transcription. These data demonstrate that inhibition of circARAP2 effectively alleviates sMICA-induced NKG2D endocytosis and NK cell desensitization, providing a novel target for therapeutic intervention in tumor immune evasion.

Soluble MIC-A, IPI, and response to treatment strongly predict survival in patients with germinal center diffuse large B cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most frequent lymphoma. MIC-A and MIC-B are the natural ligands for NKG2D, a receptor expressed in NK cells. MIC-A soluble isoforms (sMICA) have been described in different malignancies. OBJECTIVES: To analyze lymphocyte subsets and sMIC-A in germinal center DLBCL. MATERIALS AND METHODS: sMICA, sMICB, and peripheral blood lymphocyte subsets (CD4+, CD8+, NK, NKT, γδ T cells, and dendritic cells) were analyzed in 59 patients and 60 healthy donors. RESULTS: Patients had decreased numbers of type 1 and type 2 dendritic cells, NK, iNKT, CD4 T, and CD8 T cells, and higher levels of sMIC-A. The 2-year PFS for high IPI scores and high sMIC-A was 24% and 28%, respectively. The 2-year OS for high IPI scores and high sMIC-A was 42% and 33%. The 2-year PFS and OS for patients not achieving response to treatment were 0% and 10%, respectively. The MICPI score (one point each for high IPI score and high sMIC-A) showed that those patients summing two points had worse PSF and OS. CONCLUSIONS: Patients with DLBCL have decreased numbers of peripheral lymphocyte subsets and high levels of sMIC-A. The addition of sMIC-A to IPI could improve its prognostic relevance.

Prognostic Value of Serum MICA Levels as a Marker of Severity in COVID-19 Patients.

The COVID-19 global pandemic and high mortality rates necessitate the development of diagnostic and prognostic tools, as well as expanding testing capacity. Existing methods for detecting and characterizing SARS-CoV-2 infection are typically based on viral genome detection or measuring COVID-19-specific antibody levels. Despite their value, these methods are unable to predict disease outcomes in patients. Given the critical role of innate immune cells, particularly natural killer (NK) cells, in antiviral defense, this study sought to determine the prognostic value of serum secretory MHC class I polypeptide-related sequence A (sMICA) levels as an essential ligand for the NKG2D receptor, the master regulator of NK cell development and responsiveness. Serum MICA levels were measured by ELISA assay. Sera (n = 60) from SARS-CoV-2 positive patients were collected, and disease severity was determined using clinical criteria. The patient group included 30 patients with mild disease and 30 severely ill patients, as well as 30 healthy controls. Our findings revealed that serum MICA levels were significantly higher in patients than in controls, especially in cases with severe complications (P < .0001). Higher serum MICA levels may be associated with respiratory failure in COVID-19 and may serve as a marker of clinical severity in patients infected with SARS-CoV-2, particularly when clinical manifestations are insufficient to make a confident prediction.

Higher MICA levels may be associated with respiratory failure in COVID-19 infection.SMICA levels change with age, particularly for patients with severe COVID-19 disease.NKG2D ligands may have prognostic and therapeutic value for COVID-19 patients.

Clinical Efficacy of Different Thoracoscopic Surgeries for Patients With Non-small Cell Lung Cancer.

BACKGROUND: The aim of this study was to analyze the clinical efficacy of different thoracoscopic procedures in patients with non-small cell lung cancer and their correlation with matrix metalloproteinase-7 mRNA (MMPs-7 mRNA) and soluble major histocompatibility complex class I molecule A (sMICA), as well as their effect on T-cell subsets. METHODS: A total of 100 patients with non-small cell lung cancer who received different thoracoscopic surgeries were divided into the Control group (three-port thoracoscopic surgery) and the study group (single-port thoracoscopic surgery). The two groups were evaluated to compare the perioperative indicators, MMPs-7 mRNA, sMICA expression levels, T-cell subsets, postoperative pain, complication rates, and prognostic outcomes at 1-year follow-up. RESULTS: The operation time, blood loss, drainage tube placement time, incision length, and hospital stay in the study group were less than those in the control group (P < 0.05). There was no significant difference in the number of lymph node dissections between the two groups (P > 0.05). After 3 days, the expression levels of MMPs-7 mRNA and sMICA in the study group were lower than those in the control group (P < 0.05); CD4 +, CD8 +, and CD4 +/CD8 + in the study group were higher than those in the control group (P < 0.05). On days 1, 3, and 5, the visual analog score (VAS) of the study group was lower than that of the control group (P < 0.05); there was no significant difference in the complication rate between the two follow-up groups (P > 0.05), in which all patients completed the follow-up. After 1 year of follow-up, there was no significant difference in the tumor-free survival rate and overall survival rate between the two groups (P > 0.05). CONCLUSION: Compared with three-port thoracoscopic surgery, single-port thoracoscopic surgery can improve perioperative expression, shorten hospital stay, reduce serum tumor micrometastasis levels, improve immune metastasis mechanisms and reduce pain, which is of great significance to patients with non-small cell lung cancer. It is an effective, convenient, and safe surgical option that deserves wide clinical reference.

Downregulation of MICA/B tumor surface expressions and augmented soluble MICA serum levels correlate with disease stage in breast cancer.

OBJECTIVE: In this study, the profiling of the expression of major histocompatibility complex (MHC) class I-related chain A and B (MICA/B) in human breast cancer tumor tissue, saliva, and urine samples of breast cancer patients and control is carried out. MICA/B is ligand of NKG2D receptor expressed on malignant cells. The release of MICA/B from tumor tissue comprises an immune escape mechanism that impairs antitumor immunity. Based on this literature we explored the potential of soluble MICA (sMICA) as a marker in breast cancer (BC). METHODS: The expression was profiled by using immunohistochemistry (MICA/B), western blot (MICA/B) and ELISA (MICA). RESULTS: The optical density of western blot of MICA/B in different stages of BC illustrated significant difference as per one way analysis of variance and significant difference with stage III and IV by Dunnett's multiple comparisons test respectively. Analysis of sMICA in serum, saliva and urine of BC patients revealed significantly higher levels (median 41.0 ± 4.1 pg/ml in pre-treatment sera, 181.9 ± 1.6 pg/ml in saliva and 90.7 ± 1.7 pg/ml in urine) than in control (median <1.2 pg/ml). The elevated levels of sMICA were related to the cancer stage. CONCLUSIONS: The elevated levels of sMICA were observed in patients with well differentiated cancer while the poor expression of sMICA was observed in patients with poorly differentiated tumors. Tumor immunity is impaired by the release of MICA in the biofluids and may be useful for detection and diagnosis of the stage of BC.

Altered NK-cell compartment and dysfunctional NKG2D/NKG2D-ligand axis in patients with ataxia-telangiectasia.

Ataxia-telangiectasia (A-T) is a multisystem disorder caused by biallelic pathogenic variants in the gene encoding A-T mutated (ATM) kinase, a master regulator of the DNA damage response (DDR) pathway. Most A-T patients show cellular and/or humoral immunodeficiency that has been associated with cancer risk and reduced survival, but NK cells have not been thoroughly studied. Here we investigated NK cells of A-T patients with a special focus on the NKG2D receptor that triggers cytotoxicity upon engagement by its ligands (NKG2DLs) commonly induced via the DDR pathway on infected, transformed, and variously stressed cells. Using flow cytometry, we examined the phenotype and function of NK cells in 6 A-T patients as compared with healthy individuals. NKG2D expression was evaluated also by western blotting and RT-qPCR; plasma soluble NKG2DLs (sMICA, sMICB, sULBP1, ULBP2) were measured by ELISA. Results showed that A-T NK cells were skewed towards the CD56neg anergic phenotype and displayed decreased expression of NKG2D and perforin. NKG2D was reduced at the protein but not at the mRNA level and resulted in impaired NKG2D-mediated cytotoxicity in 4/6 A-T patients. Moreover, in A-T plasma we found 24-fold and 2-fold increase of sMICA and sULBP1, respectively, both inversely correlated with NKG2D expression. Overall, NK cells are disturbed in A-T patients showing reduced NKG2D expression, possibly caused by persistent engagement of its ligands, that may contribute to susceptibility to cancer and infections and represent novel targets for therapeutic interventions.

Clinical relevance of NKT cells and soluble MIC-A in Hodgkin lymphoma.

Previous studies demonstrated that the majority of Hodgkin lymphoma (HL) patients achieve response after treatment, while 5% become refractory. Studies analyzing the role of lymphocyte subsets in peripheral blood are limited. This investigation sought to evaluate peripheral blood lymphocyte subsets and soluble MHC class I chain-related proteins A and B (sMIC-A/B) and their correlation with survival in patients with newly diagnosed HL. The study recruited 36 patients and 72 healthy donors. HL patients showed a decrease in CD4, B, monocytes, NK, and NKT cells; and an increase in γ-δ T cells and soluble MIC-A serum levels. Higher values of s-MIC-A  >100 ng/mL and NKT cells >40 µL correlated with poor overall survival (OS). In conclusion, in HL peripheral blood CD4 T and B cells, monocytes, NK, and NKT cells were decreased, while s-MIC-A and γ-δ T cells increased. Higher values of s-MIC-A and NKT cells correlated with poor survival.

Association of serial serum major histocompatibility complex class I chain-related A measurements with hepatocellular carcinoma in chronic hepatitis C patients after viral eradication.

BACKGROUND AND AIM: Major histocompatibility complex class I chain-related A (MICA) genetic variants and their serum levels (sMICA) were associated with the development of hepatitis C virus-related hepatocellular carcinoma (HCC) in untreated cohorts. The dynamic changes in serial sMICA levels and their association with HCC in the post-curative status are elusive. METHODS: Single nucleotide polymorphism rs2596542 of MICA and serial sMICA levels were analyzed in chronic hepatitis C patients with a sustained virologic response after antivirals. Forty-two patients who developed HCC and 84 age-matched, gender-matched, and cirrhosis propensity score-matched non-HCC controls were compared. Serial sMICA levels were measured within 6 months before treatment initiation (pre-sMICA), 6 months after the end of treatment (post-sMICA), and on the last visit before the development (or not) of HCC (last-sMICA). RESULTS: Cox regression analysis revealed that last-sMICA was the only predictive factor of HCC development (hazard ratio/95% confidence interval: 2.27 (per 1 log pg/mL increase)/1.672-3.082, P < 0.001). Patients without HCC development showed a significantly reduced trend of sMICA levels during follow-up (trend P = 0.001), which was observed only in GG genotype (trend P < 0.001) but not A allele carriers (P = 0.88). In contrast, patients with HCC showed an increased trend of sMICA levels (trend P = 0.024). However, only the GG genotype "high expressors" (trend P = 0.06) but not A allele carriers (P = 0.18) showed a correlation of substantially increased trend of sMICA levels and HCC development. CONCLUSIONS: Serial sMICA levels were associated with HCC development in SVR patients. The clinical utility of this finding is restricted to MICA rs2596542 GG genotype carriers.

A Valine Mismatch at Position 129 of MICA Is an Independent Predictor of Cytomegalovirus Infection and Acute Kidney Rejection in Simultaneous Pancreas⁻Kidney Transplantation Recipients.

The polymorphic major histocompatibility complex class I chain-related molecule A (MICA) and its soluble form (sMICA) interact with activating receptor natural-killer group 2 member D (NKG2D) on natural-killer (NK) and T cells, thereby modifying immune responses to transplantation and infectious agents (e.g., cytomegalovirus). Two single-nucleotide polymorphisms (SNPs), rs2596538GA in the MICA promoter and rs1051792AG in the coding region (MICA-129Val/Met), influence MICA expression or binding to NKG2D, with MICA-129Met molecules showing higher receptor affinity. To investigate the impact of these SNPs on the occurrence of cytomegalovirus infection or acute rejection (AR) in individuals who underwent simultaneous pancreas⁻kidney transplantation (SPKT), 50 recipient-donor pairs were genotyped, and sMICA levels were measured during the first year post-transplantation. Recipients with a Val-mismatch (recipient Met/Met and donor Val/Met or Val/Val) showed shorter cytomegalovirus infection-free and shorter kidney AR-free survival. Additionally, Val mismatch was an independent predictor of cytomegalovirus infection and kidney AR in the first year post-transplantation. Interestingly, sMICA levels were lower in rs2596538AA and MICA129Met/Met-homozygous recipients. These results provide further evidence that genetic variants of MICA influence sMICA levels, and that Val mismatch at position 129 increases cytomegalovirus infection and kidney AR risk during the first year post-SPKT.

MICA-129 A/G dimorphism, its relation to soluble mica plasma level and spontaneous preterm birth: A case-control study.

The aim of this case- control study was to investigate the association between preterm birth (PTB), MICA-129 A/G dimorphism and sMICA levels. Fifty pregnant women with singleton pregnancy and previous PTB, or clinic diagnostic of threatened preterm labor in the actual pregnancy, or cervical length less than 25 mm and 50 healthy pregnant women were enrolled. DNA was extracted for genotyping for MICA-129 A/G by real-time PCR and sMICA plasma level was quantified by sandwich ELISA assay. Clinical and socioeconomic characteristics, results of TaqMan® genotyping and ELISA quantification were compared between the groups using qui-square, Fisher´s exact or Mann-Whitney test. A binary logistic regression model was used to predict PTB. The correlation between MICA-129 A/G genotypes and sMICA levels was investigated. There were not statistically significant differences between MICA-129 A/G polymorphism and sMICA plasma level.There was found a correlation between MICA-129 val/val genotype and higher levels of sMICA (ρ: -0.342; p:0.001). The presence of MICA-129  val/val genotype may be influencing sMICA expression.

Association of MICA-129 polymorphism and circulating soluble MICA level with rheumatoid arthritis in a south Indian Tamil population.

INTRODUCTION: Rheumatoid arthritis (RA) is a clinically heterogeneous chronic inflammatory disorder characterized by synovitis leading to joint destruction. Both genetic and environmental factors are involved in the pathogenesis of RA. Significant dysregulation of NKG2D, an activating receptor of natural killer and certain autoreactive T cells as well as its ligand major histocompatibility complex class I chain-related gene A (MICA) has been implicated in perpetuating the pathology of RA. Since the genetic polymorphism in MICA gene (MICA-129 met/val polymorphism at codon 129) is known to affect its binding affinity to NKG2D, we explored its influence on RA susceptibility and disease severity. METHODS: The MICA-129 met/val polymorphism was examined in 270 patients with RA and 232 healthy controls by TaqMan 5'-nuclease assay. Serum soluble MICA (sMICA) was measured in a subset of 89 patients and 80 controls by enzyme-linked immunosorbent assay. RESULTS: We observed that the frequency of MICA-129 val allele (73% vs. 65%, Pc = 0.006, odds ratio = 1.48, 95% CI = 1.12-1.95) was higher in patients than in controls. sMICA levels were significantly higher in patients with RA than in controls (P < 0.0001). sMICA levels were higher in patients with val/val genotype than in those with met/val or met/met genotype (P = 0.03). The MICA-129 val/val genotype was associated with high titers of sMICA in patients with deforming RA phenotype (P = 0.02), suggesting a role in determination of severity of RA. CONCLUSION: MICA-129 val/val genotype, associated with higher levels of circulating sMICA, may influence disease susceptibility and associate with increased severity of RA in south Indian Tamils.

Soluble MICA is elevated in pancreatic cancer: Results from a population based case-control study.

Pancreatic cancer is diagnosed at a late stage and has one of the highest cancer mortality rates in the United States, creating an urgent need for novel early detection tools. A candidate biomarker for use in early detection is the soluble MHC class I-related chain A (s-MICA) ligand, which pancreatic tumors shed to escape immune detection. The objective of this study was to define the association between s-MICA levels and pancreatic cancer, in a population-based case-control study. S-MICA was measured in 143 pancreatic cancer cases and 459 controls. Unconditional logistic regression was used to calculate odds ratio (OR) for pancreatic cancer and 95% confidence intervals (CI). There was a positive association between increasing s-MICA levels and pancreatic cancer: compared to the lowest tertile, the ORs for pancreatic cancer were 1.25 (95%CI: 0.75-2.07) and 2.10 (95%CI: 1.29-3.42) in the second and highest tertiles, respectively (P-trend = 0.02). Our study supports previous work demonstrating a positive association between plasma s-MICA levels and pancreatic cancer.

Diversity of the association of serum levels and genetic variants of MHC class I polypeptide-related chain A with liver fibrosis in chronic hepatitis C.

BACKGROUND/AIMS: Genetic variants of MHC class I polypeptide-related chain A (MICA) at rs2596542 have been associated with hepatocellular carcinoma. The linkage between serum MICA (sMICA) and liver fibrosis in chronic hepatitis C is elusive. RESULTS: Linear regression analysis revealed that sMICA were independently correlated to α-fetoprotein (ß: 0.149; 95% confidence interval [CI]: 0.001, 0.003; P = 0.007)and MICA rs2596542 GG genotype (ß: 0.209; 95% CI: 0.153, 0.483; P < 0.001). While patients were stratified by MICA genetic variants, advanced fibrosis was the only factor independently correlated to sMICA among A allele carriers (ß: 0.234; 95% CI: 0.107, 0.543; P = 0.004) but not among non-A allele carriers. Logistic regression analysis revealed that factors associated with advanced liver fibrosis was sMICA (OR/CI: 2.996/1.428-6.287, P = 0.004) and platelet counts (OR/CI: 0.988/0.982-0.994, P < 0.001) in MICA rs2596542 A allele carriers. sMICA > 50 pg/mL provided a positive predictive value of 72 % in predicting advanced liver fibrosis (F3-4) and of 90% in significant fibrosis (> F2) in MICA rs2596542 A allele carriers. MATERIALS AND METHODS: Serum level and single nucleotide polymorphism at rs2596542 of MICA were tested for the association with liver fibrosis in 319 biopsy proven chronic hepatitis C patients. CONCLUSIONS: Levels of sMICA were highly correlated to liver disease severity in chronic hepatitis C patients who carried the MICA rs738409 A allele. Patients possessing the genetic predisposition had a higher likelihood of progressed liver fibrosis if they expressed higher sMICA levels.

Genetics Variants and Serum Levels of MHC Class I Chain-related A in Predicting Hepatocellular Carcinoma Development in Chronic Hepatitis C Patients Post Antiviral Treatment.

BACKGROUND/AIMS: The genome-wide association study has shown that MHC class I chain-related A (MICA) genetic variants were associated with hepatitis C virus (HCV) related hepatocellular carcinoma (HCC). The impact of the genetic variants and its serum levels on post-treatment cohort is elusive [corrected]. METHODS: MICA rs2596542 genotype and serum MICA (sMICA) levels were evaluated in 705 patients receiving antiviral therapy. RESULTS: Fifty-eight (8·2%) patients developed HCC, with a median follow-up period of 48·2 months (range: 6­129 months). The MICA A allele was associated with a significantly increased risk of HCC development in cirrhotic non-SVR patients but not in patients of non-cirrhotic and/or with SVR. For cirrhotic non-SVR patients, high sMICA levels (HR/CI: 5·93/1·86­26·38, P = 0·002) [corrected] and the MICA rs2596542 A allele (HR/CI: 4·37/1·52­12·07, P = 0·002) were independently associated with HCC development. The risk A allele or GG genotype with sMICA > 175 ng/mL provided the best accuracy (79%) and a negative predictive value of 100% in predicting HCC. CONCLUSIONS: Cirrhotic patients who carry MICA risk alleles and those without risk alleles but with high sMICA levels possessed the highest risk of HCC development once they failed antiviral therapy.

Relevance of serum biomarkers associated with melanoma during follow-up of anti-CTLA-4 immunotherapy.

Metastatic melanoma is a rapidly spreading cancer whose prognosis remains poor although important therapy advances in recent years. Ipilimumab, an anti-CTLA-4 immunotherapy used in advanced melanoma, is an effective immunotherapy alone or combined with other agents but with few predictive biomarkers of response. Here, we sought to analyze the potential of S100B, MIA, soluble MICA, anti-MICA antibodies and LDH as serum biomarkers of response and survival in a cohort of 77 advanced melanoma patients subjected to ipilimumab. Lower levels of S100B, and LDH at baseline and at weeks 3 and 6 correlated to a better response and survival. After multivariate analysis LDH maintained its independence at baseline and week 6, whereas S100B might be a useful tool for anti-CTLA-4 treatment monitoring after the first two doses of ipilimumab (W6). In addition, higher sMICA serum levels at baseline were associated with less frequency of irAEs.

Failure recovery of circulating NKG2D+CD56dimNK cells in HBV-associated hepatocellular carcinoma after hepatectomy predicts early recurrence.

Dysfunction of natural killer (NK) cells has been implicated in the failure of antitumor immune responses in hepatocellular carcinoma (HCC) patients. However, the changes of NK profile in peripheral blood after surgery and tumor tissues of HCC patients, as well as the underlying reason and the significance are vague. Here, we observed that the frequencies of circulating NKG2D+CD56dimNK cells decreased significantly in HBV-related HCC and were negatively correlated with the levels of serum TGF-ß and soluble MICA (sMICA). In vitro experiments confirmed that the TGF-ß and sMICA in tumor tissue homogenates, as well as sMICA in HCC cells culture supernatants could reduce the frequency of NKG2D+CD56dimNK cells. In addition, in HCC patients the lower frequency of circulating NKG2D+CD56dimNK cells was associated with larger tumor size and/or higher serum GGT. Noticeably, the frequency of NKG2D+CD56dimNK cells at one month after surgery usually failed to restore in early recurrent patients, and that frequency was negatively associated with early recurrence and shorter overall survival. These results suggest that declined frequency of NKG2D+CD56dimNK cells in HCC was associated with higher TGF-ß and sMICA production, and low frequency of circulating NKG2D+CD56dimNK cells at one month after surgery may predict poor prognosis of HBV-related HCC patients accepting hepatectomy.

Assessment of changes in expression and presentation of NKG2D under influence of MICA serum factor in different stages of breast cancer.

Breast cancer is the most common cancer in women worldwide. In this study, we correlated the serum level of major histocompatibility complex class I-related chain A (sMICA) with expression and presentation of NKG2D receptors on NK cells among patients with breast cancer. Peripheral blood (PB) samples were collected from 49 healthy and 49 breast cancer patients before surgery and chemotherapy. The expression and presentation of NKG2D were assessed using qRT-PCR and flow cytometry, respectively. Furthermore, sMICA levels were determined using ELISA. In flow cytometry, whole blood samples were stained with anti-CD56/NKG2D/CD3 and the obtained results were analyzed using WinMDI software. In addition, SPSS software was used for statistical analysis of data. Significantly higher levels sMICA were detected in the sera of the majority of cancer patients in contrast to healthy volunteers (P < 0.001). The expression and presentation of NKG2D receptor were significantly lower than those in healthy persons, and with an inverse correlation to sMICA and positively correlated with tumor stage. Our study showed that sMICA may have an important role in diminishing the expression and presentation of NKG2D receptor in breast cancer patients and proposes the notion that sMICA can be a target candidate for treatment of breast cancer.