CDKN2A/B deletion in IDH-mutant astrocytomas: An evaluation by Fluorescence in-situ hybridization.

INTRODUCTION: CDKN2A/B homozygous deletion is one of the defining features of grade 4 in IDH-mutant astrocytic tumours. AIM: To evaluate CDKN2A/B-deletion in IDH-mutant astrocytic tumours and its clinicopathological impact. MATERIALS AND METHODS: CDKN2A/B-deletion was evaluated by Fluorescence in-situ hybridisation (FISH) and interpreted by two recently accepted methods. RESULTS: Eighty-three out of 94 cases (histologically-grade 2: 3, grade 3: 46, grade 4: 34) were interpretable on FISH. Concordant CDKN2A/B-deletion was observed in 71% (27/38) of lower-grade tumours (n = 49) and 90% (27/30) of histological grade 4 tumours (n = 34). Both the interpretation methods showed good agreement (Kappa = 0.75). CDKN2A/B-deletion showed an inverse correlation for < 10% MIB-1 labeling index (p = 0.01) while that by method-2 showed a significant correlation for grade 4 (p = 0.02). No significant correlation was observed for any other clinicopathological parameters. Twenty-four patients showed progression/recurrence (including deaths), and no significant difference in frequency of CDKN2A/B deletion was observed among cases with disease progression across different histological grades. CONCLUSIONS: CDKN2A/B-deletion was observed across all the histological grades of IDH-mutant astrocytic tumours, expectedly more in the higher grade. FISH, as a method, can be used for the detection of CDKN2A/B homozygous deletion, when there is concordant interpretation.

Evaluation of rs10811661 polymorphism in CDKN2A / B in colon and gastric cancer.

One of the causes of colon and gastric cancer is the dysregulation of carcinogenic genes, tumor inhibitors, and micro-RNA. The purpose of this study is to apply rs10811661 polymorphism in CDKN2A /B gene as an effective biomarker of colon cancer and early detection of gastric cancer. As a result,400 blood samples, inclusive of 200 samples from healthy individuals and 200 samples (100 samples from intestinal cancer,100 samples from stomach cancer) from the blood of someone with these cancers, to determine the genotype of genes in healthful and ill people through PCR-RFLP approach and Allelic and genotypic tests of SPSS software. To observe the connection between gastric cancer and bowel cancer risk and genotypes, the t-student test for quantitative variables and Pearson distribution for qualitative variables have been tested and the results have been evaluated using the Chi-square test. The effects confirmed that the highest frequency of TT genotypes is in affected individuals and CC genotype is in healthful individuals. In addition, it confirmed that women were more inclined than men to T3 tumor invasion and most grade II and III colon cancers, and in older sufferers with gastric cancer, the grade of tumor tended to be grade I. Among genetic variety and rs10811661, with invasiveness, there is a tumor size and degree in the affected person. In summary, our findings suggest that the rs10811661 polymorphism of the CDKN2A / B gene is strongly associated with the occurrence of intestinal cancer and stomach is linked to its potential role as a prognostic biomarker for the management of bowel cancer and stomach.

Association between cyclin-dependent kinase inhibitor 2B antisense RNA 1 and zinc finger homeobox 3 gene polymorphisms and COVID-19 severity.

BACKGROUND: There is no doubt about the cardiovascular complications of coronavirus disease 2019 (COVID-19). Several genetic studies have demonstrated an association between genetic variants in a region on chromosome 9p21 and in a region on chromosome 16q22 with myocardial infarction (MI) and atrial fibrillation (AF) accompanied by cerebral infarction (CI), respectively. OBJECTIVES: MI and CI susceptibility in patients with CDKN2B-AS1 and ZFHX3 polymorphisms, respectively, may have an effect on COVID-19 severity. We aimed to investigate whether there is an association between the cyclin-dependent kinase inhibitor 2B antisense RNA 1 (CDKN2B-AS1) rs1333049 and zinc finger homeobox 3 (ZFHX3) rs2106261 single nucleotide polymorphisms (SNPs) and the degree of COVID-19 severity. SUBJECTS AND METHODS: This current work was carried out on 360 subjects. They were classified into three groups: 90 severe COVID-19 cases, 90 moderate COVID-19 cases and 180 age- and gender-matched healthy controls. All subjects underwent genotyping of CDKN2B-AS1 (rs1333049) and ZFHX3 (rs2106261) by real-time PCR. RESULTS: The frequency of G/C in CDKN2B-AS1 (rs1333049) was higher in severe and moderate COVID-19 patients than in controls (71.1% and 53.3% vs. 37.8%). The frequency of the C/C of CDKN2B-AS1 (rs1333049) was higher in moderate COVID-19 patients than in controls (26.7% vs. 13.3%). There were no significant differences regarding genotype frequency and allelic distribution of ZFHX3 (rs2106261) between COVID-19 patients and healthy controls. CONCLUSION: CDKN2B-AS1 (rs1333049) gene polymorphism may play a role in determining the degree of COVID-19 severity. Further studies on its effect on cyclins and cyclin-dependent kinases (CDKs) [not measured in our study] may shed light on new treatment options for COVID-19.

Expression analysis of cytoskeleton regulator RNA and Cyclin Dependent Kinase Inhibitor 2B genes in breast cancer.

BACKGROUND: Breast cancer has been found to be associated with deregulation of several non-coding genes and mRNA coding genes. OBJECTIVE: To assess expressions of CYTOR and CDKN2B in breast cancer and adjacent samples and find their relevance with clinical data. METHODS: We enumerated expression level of CDKN2B and CYTOR in 43 newly diagnosed breast cancer samples and their adjacent specimens using real-time PCR method Expression data was judged using Wilcoxon matched-pairs signed rank test. RESULTS: CYTOR level was higher in tumors compared with adjacent tissues. Nevertheless, there was no difference in expression of CDKN2B between these two sets of tissues. ROC curve analysis showed that CYTOR levels can differentiate between tumoral and adjacent tissues with AUC, specificity and sensitivity values of 0.65, 37% and 92% (P= 0.017). There was a positive correlation between expression levels of CYTOR and CDKN2B genes in breast cancer tissues (r= 0.5 and P= 0.0008) as well as adjacent tissues (r= 0.79 and P< 0.0001). Relative expression level of CDKN2B in normal tissues was associated with clinical stage (P= 0.014). Moreover, relative expression level of CDKN2B in tumor tissues was associated with the body weight. There was no other association between expressions of CYTOR and CDKN2B and clinical or pathological variables. CONCLUSIONS: Cumulatively, this study offers evidence for involvement of these genes in the pathoetiology of breast cancer.

KIT A502_Y503 duplication mutation serves as a potential and universal target for neoantigen peptide in Chinese GIST patients.

BACKGROUND AND AIM: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor with high prevalence of KIT and PDGFRA mutations. Few effective treatments can be exploited in imatinib or sunitinib resistant cases. While in immunotherapy, application of the highly individualized cancer neoantigen vaccines is hampered due to high economic and time cost. In this study we identified the most frequent mutation in Chinese GIST patients and predicted candidate neopeptide by next generation sequencing (NGS). METHODS: Tumor tissues and matched blood samples of 116 Chinese GIST patients were collected. Genomic profile was detected through NGS, and 450 cancer genes were deeply sequenced. KIT mutations were identified, and long peptides containing the mutation were queried in NetMHCpan 4.0 tools to predict MHC class I binding of mutant peptides. RESULTS: The most frequent mutated genes in detected GIST patients were KIT (81.9%, 95/116), CDKN2A (18.97%, 22/116), and CDKN2B (15.52%, 18/116) in this cohort. The most common mutation of KIT was A502_Y503 duplication (15.93%, 18/113) in exon 9. Among the 116 cases, 103 were HLA I genotyped, and 101 were HLA II genotyped. In total, 16 samples with the mutation of KIT p.A502_Y503dup were identified to produce neoantigens with qualified HLA affinity. CONCLUSIONS: KIT hotspot mutation (p.A502_Y503dup) has the highest incidence, which may further eliminate the need for whole genome sequencing and patient-specific neoantigen prediction and synthesis. Therefore, for those carrying such mutation, accounting for around 16% of Chinese GIST patients and are usually less sensitive to imatinib, effective immunotherapies are in prospect.

Joint Effects Between CDKN2B/P15 Methylation and Environmental Factors on the Susceptibility to Gastric Cancer.

BACKGROUND: The incidence of gastric cancer has long been at a high level in China, seriously affecting the health of Chinese people. AIMS: This case‒control study was performed to identify gene methylation biomarkers of gastric cancer susceptibility. METHODS: A total of 393 gastric cancer cases and 397 controls were included in this study. Gene methylation in peripheral blood leukocytes was detected by a methylation-sensitive high-resolution melting method, and the Helicobacter pylori antibody presence was semi-quantified in serum by ELISA. RESULTS: Individuals with total methylation of CDKN2B/P15 had a 1.883-fold (95%CI: 1.166-3.040, P = 0.010) risk of gastric cancer compared with unmethylated individuals. Individuals with both CDKN2B/P15 and NEUROG1 methylation had a higher risk of gastric cancer (OR = 2.147, 95% CI: 1.137-4.073, P = 0.019). The interaction between CDKN2B/P15 and NEUROG1 total methylation on gastric cancer risk was affected by the pattern of adjustment. In addition, the joint effects between CDKN2B/P15 total methylation and environmental factors, such as freshwater fish intake (OR = 6.403, 95% CI = 2.970-13.802, P < 0.001), irregular diet (OR = 5.186, 95% CI = 2.559-10.510, P < 0.001), unsanitary water intake (OR = 2.238, 95% CI = 1.144-4.378, P = 0.019), smoking (OR = 2.421, 95% CI = 1.456-4.026, P = 0.001), alcohol consumption(OR = 2.163, 95% CI = 1.309-3.576, P = 0.003), and garlic intake(OR = 0.373, 95% CI = 0.196-0.709, P = 0.003) on GC risk were observed, respectively. However, CDKN2B/P15 and NEUROG1 total methylation were not associated with gastric cancer prognosis. CONCLUSION: CDKN2B/P15 methylation in peripheral blood may be a potential biomarker for evaluating susceptibility to gastric cancer. The joint effects between CDKN2B/P15 methylation and environmental factors may also contribute to gastric cancer susceptibility.

Methyltransferase Inhibition Enables Tgfß Driven Induction of CDKN2A and B in Cancer Cells.

CDKN2A/B deletion or silencing is common across human cancer, reinforcing the general importance of bypassing its tumor suppression in cancer formation or progression. In rhabdomyosarcoma (RMS) and neuroblastoma, two common childhood cancers, the three CDKN2A/B transcripts are independently expressed to varying degrees, but one, ARF, is uniformly silenced. Although TGFß induces certain CDKN2A/B transcripts in HeLa cells, it was unable to do so in five tested RMS lines unless the cells were pretreated with a broadly acting methyltransferase inhibitor, DZNep, or one targeting EZH2. CDKN2A/B induction by TGFß correlated with de novo appearance of three H3K27Ac peaks within a 20 kb cis element ∼150 kb proximal to CDKN2A/B. Deleting that segment prevented their induction by TGFß but not a basal increase driven by methyltransferase inhibition alone. Expression of two CDKN2A/B transcripts was enhanced by dCas9/CRISPR activation targeting either the relevant promoter or the 20 kb cis elements, and this "precise" manipulation diminished RMS cell propagation in vitro. Our findings show crosstalk between methyltransferase inhibition and TGFß-dependent activation of a remote enhancer to reverse CDKN2A/B silencing. Though focused on CDKN2A/B here, such crosstalk may apply to other TGFß-responsive genes and perhaps govern this signaling protein's complex effects promoting or blocking cancer.

Protein phosphatase 2A activators reverse age-related behavioral changes by targeting neural cell senescence.

The contribution of cellular senescence to the behavioral changes observed in the elderly remains elusive. Here, we observed that aging is associated with a decline in protein phosphatase 2A (PP2A) activity in the brains of zebrafish and mice. Moreover, drugs activating PP2A reversed age-related behavioral changes. We developed a transgenic zebrafish model to decrease PP2A activity in the brain through knockout of the ppp2r2c gene encoding a regulatory subunit of PP2A. Mutant fish exhibited the behavioral phenotype observed in old animals and premature accumulation of neural cells positive for markers of cellular senescence, including senescence-associated ß-galactosidase, elevated levels cdkn2a/b, cdkn1a, senescence-associated secretory phenotype gene expression, and an increased level of DNA damage signaling. The behavioral and cell senescence phenotypes were reversed in mutant fish through treatment with the senolytic ABT263 or diverse PP2A activators as well as through cdkn1a or tp53 gene ablation. Senomorphic function of PP2A activators was demonstrated in mouse primary neural cells with downregulated Ppp2r2c. We conclude that PP2A reduction leads to neural cell senescence thereby contributing to age-related behavioral changes and that PP2A activators have senotherapeutic properties against deleterious behavioral effects of brain aging.

PRMT6 functionally associates with PRMT5 to promote colorectal cancer progression through epigenetically repressing the expression of CDKN2B and CCNG1.

BACKGROUND: Protein arginine methyltransferase 6 (PRMT6) is a type I arginine methyltransferase that asymmetrically dimethylates histone H3 arginine 2 (H3R2me2a). However, the biological roles and underlying molecular mechanisms of PRMT6 in colorectal cancer (CRC) remain unclear. METHODS: PRMT6 expression in CRC tissue was examined using immunohistochemistry. The effect of PRMT6 on CRC cells was investigated in vitro and in vivo. Mass spectrometry, co-immunoprecipitation and GST pulldown assays were performed to identify interaction partners of PRMT6. RNA-seq, chromatin immunoprecipitation, Western blot and qRT-PCR assays were used to investigate the mechanism of PRMT6 in gene regulation. RESULTS: PRMT6 is significantly upregulated in CRC tissues and facilitates cell proliferation of CRC cells in vitro and in vivo. Through RNA-seq analysis, CDKN2B (p15INK4b) and CCNG1 were identified as new transcriptional targets of PRMT6. PRMT6-dependent H3R2me2a mark was predominantly deposited at the promoters of CDKN2B and CCNG1 in CRC cells. Furthermore, PRMT5 was firstly characterized as an interaction partner of PRMT6. Notably, H3R2me2a coincides with PRMT5-mediated H4R3me2s and H3R8me2s marks at the promoters of CDKN2B and CCNG1 genes, thus leading to transcriptional repression of these genes. CONCLUSIONS: PRMT6 functionally associates with PRMT5 to promote CRC progression through epigenetically repressing the expression of CDKN2B and CCNG1. These insights raise the possibility that combinational intervention of PRMT6 and PRMT5 may be a promising strategy for CRC therapy.

Organochlorine pesticides may induce leukemia by methylation of CDKN2B and MGMT promoters and histone modifications.

Epigenetics is the science of altering gene expression without changing nucleotide sequences and may be induced by various environmental factors, including pesticides. The aim of this study was to investigate certain epigenetic changes including the methylation of CDKN2B, CDKN2A, and MGMT gene promoters and histone modifications of H3K9ac, H4K16ac, H4K20me3, and H3K4me3, as well as their association with the levels of organochlorine pesticides (OCPs) in children with acute lymphoblastic leukemia (ALL). The evaluation of OCP levels, promoter methylation, gene expression, and expression of histone modifications was performed by gas chromatography (GC), methylation-specific polymerase chain reaction (MS-PCR), reverse transcription PCR (RT-PCR), and western blotting, respectively. The results indicated that 76.2 % of CDKN2B promoters and 85.1 % of MGMT promoters were hypermethylated in children with ALL compared to healthy children. In addition, the relative expression of CDKN2B, MGMT, H4K16ac, and H3K4me3 showed a significant decrease in children with ALL compared to healthy children. Levels of OCPs in children with ALL were significantly higher than in healthy children. Furthermore, the results revealed that the rise in the OCP levels was associated with an increase in methylation at the promoter level of CDKN2B and MGMT as well as a decrease in the relative expression of H4K16ac and H3K4me3. Therefore, it can be concluded that exposure to OCPs is associated with the induction of epigenetic changes at the level of DNA and histones, which may lead to leukemia.

Asian-specific 3'UTR variant in CDKN2B associated with risk of pituitary adenoma.

BACKGROUND: Previous genomewide association studies (GWASs), single nucleotide polymorphisms (SNPs) on cyclin-dependent kinase inhibitor 2 A (CDKN2A), cyclin-dependent kinase inhibitor 2B (CDKN2B), and cyclin-dependent kinase inhibitor 2B antisense RNA1 (CDKN2B-AS1) were reported as risk loci for glioma, a subgroup of the brain tumor. To further characterize this association with the risk of brain tumors in a Korean population, we performed a fine-mapping association study of CDKN2A, CDKN2B, and CDKN2B-AS1. METHODS AND RESULTS: A total of 17 SNPs were selected and genotyped in 1,439 subjects which were comprised of 959 patients (pituitary adenoma 335; glioma 324; meningioma 300) and 480 population controls (PCs). We discovered that a 3'untranslated region (3'UTR) variant, rs181031884 of CDKN2B (Asian-specific variant), had significant association with the risk of pituitary adenoma (PA) (Odds ratio = 0.58, P = 0.00003). Also, rs181031884 appeared as an independent causal variant among the significant variants in CDKN2A and CDKN2B, and showed dose-dependent effects on PA. CONCLUSIONS: Although further studies are needed to verify the impact of this variant on PA susceptibility, our results may help to understand CDKN2B polymorphism and the risk of PA.

The epigenetic impact of suberohydroxamic acid and 5­Aza­2'­deoxycytidine on DNMT3B expression in myeloma cell lines differing in IL­6 expression.

Gene inactivation of the cyclin­dependent kinase inhibitors p16INK4a, p15INK4b and p21WAF is frequently mediated by promoter gene methylation, whereas histone deacetylases (HDACs) control gene expression through their ability to deacetylate proteins. The effect of suberohydroxamic acid (SBHA) and 5­Aza­2'­deoxycytidine (Decitabine) (DAC) treatments on the transcription of CDKN2A, CDKN2B and CDKN1A genes, and their effects on molecular biological behavior were examined in two myeloma cell lines, RPMI8226 and U266, which differ in p53­functionality and IL­6 expression. In both tested myeloma cell lines, a non­methylated state of the CDKN2B gene promoter region was detected with normal gene expression, and the same level of p15INK4b protein was detected by immunocytochemical staining. Furthermore, in myeloma cells treated with SBHA and DAC alone, the expression of both p15INK4b and p21WAF was significantly upregulated in RPMI8226 cells (p53­functional, without IL­6 expression), whereas in the U266 cell line (p53 deleted, expressing IL­6) only p21WAF expression was significantly increased. Moreover, the analysis revealed that treatment with DAC induced DNMT3B enhancement in U266 cells. In conclusion, in myeloma cells with IL­6 expression, significantly increased DNMT3B expression indicated the tumorigenic consequences of 5­Aza­2'deoxycytidine treatment, which requires careful use in diseases involving epigenetic dysregulation, such as multiple myeloma (MM).

Reciprocal Regulation between lncRNA ANRIL and p15 in Steroid-Induced Glaucoma.

Steroid-induced glaucoma (SIG) is the most common adverse steroid-related effect on the eyes. SIG patients can suffer from trabecular meshwork (TM) dysfunction, intraocular pressure (IOP) elevation, and irreversible vision loss. Previous studies have mainly focused on the role of extracellular matrix turnover in TM dysfunction; however, whether the cellular effects of TM cells are involved in the pathogenesis of SIG remains unclear. Here, we found that the induction of cellular senescence was associated with TM dysfunction, causing SIG in cultured cells and mouse models. Especially, we established the transcriptome landscape in the TM tissue of SIG mice via microarray screening and identified ANRIL as the most differentially expressed long non-coding RNA, with a 5.4-fold change. The expression level of ANRIL was closely related to ocular manifestations (IOP elevation, cup/disc ratio, and retinal nerve fiber layer thickness). Furthermore, p15, the molecular target of ANRIL, was significantly upregulated in SIG and was correlated with ocular manifestations in an opposite direction to ANRIL. The reciprocal regulation between ANRIL and p15 was validated using luciferase reporter assay. Through depletion in cultured cells and a mouse model, ANRIL/p15 signaling was confirmed in cellular senescence via cyclin-dependent kinase activity and, subsequently, by phosphorylation of the retinoblastoma protein. ANRIL depletion imitated the SIG phenotype, most importantly IOP elevation. ANRIL depletion-induced IOP elevation in mice can be effectively suppressed by p15 depletion. Analyses of the single-cell atlas and transcriptome dynamics of human TM tissue showed that ANRIL/p15 expression is spatially enriched in human TM cells and is correlated with TM dysfunction. Moreover, ANRIL is colocalized with a GWAS risk variant (rs944800) of glaucoma, suggesting its potential role underlying genetic susceptibility of glaucoma. Together, our findings suggested that steroid treatment promoted cellular senescence, which caused TM dysfunction, IOP elevation, and irreversible vision loss. Molecular therapy targeting the ANRIL/p15 signal exerted a protective effect against steroid treatment and shed new light on glaucoma management.

Monitoramento do horizonte tecnológico: Medicamentos para tratamento de primeira linha do câncer de próstata metastático resistente à castração / Monitoring the technology horizon: Drugs for first-line treatment of metastatic castration-resistant prostate cancer

A DOENÇA: O câncer de próstata (CP) é uma doença heterogênea com diversos subtipos, que acomete a glândula próstata. A função dessa glândula é a produção do líquido prostático e do líquido seminal, que juntos são capazes de nutrir os espermatozoides e auxiliá-los na sua mobilidade. No adulto jovem a próstata possui o tamanho aproximado de uma ameixa, e pode de modo fisiológico aumentar de tamanho, de acordo com o envelhecimento. Na maioria dos casos o CP apresenta evolução silenciosa, podendo não apresentar sinais e sintomas em sua fase inicial. Entretanto, as manifestações clínicas mais comuns são: dificuldade de urinar, demora em iniciar ou finalizar o jato urinário, diminuição do jato urinário, necessidade de urinar mais vezes durante o dia ou a noite e presença de sangue na urina. Como esses sinais e sintomas são inespecíficos é necessário a avaliação médica para fins de diagnóstico diferencial. TRATAMENTOS SISTÊMICOS DE PRIMEIRA LINHA DISPONÍVEIS: As Diretrizes Diagnósticas e Terapêuticas (DDT) do adenocarcinoma de próstata, publicadas em 2016, estão em processo de atualização no momento. Para pacientes assintomáticos ou pouco sintomáticos é recomendado como tratamento de primeira linha a utilização de novos agentes inibidores do eixo de sinalização androgênica, preferencialmente, abiraterona ou enzalutamida (nível de evidência 1 e força de recomendação A). Para pacientes sintomáticos é recomendado como tratamento de primeira linha a quimioterapia com docetaxel e o radiofármaco Radium-223 (nível de evidência 1 e força de recomendação A). ESTRATÉGIA DE BUSCA: Os medicamentos em fase de desenvolvimento para o tratamento de primeira linha de pacientes com câncer de próstata metastático

9p21.3 Microdeletion involving CDKN2A/2B in a young patient with multiple primary cancers and review of the literature.

Germline pathogenic variants in CDKN2A predispose to various cancers, including melanoma, pancreatic cancer, and neural system tumors, whereas CDKN2B variants are associated with renal cell carcinoma. A few case reports have described heterozygous germline deletions spanning both CDKN2A and CDKN2B associated with a cancer predisposition syndrome (CPS) that constitutes a risk of cancer beyond those associated with haploinsufficiency of each gene individually, indicating an additive effect or a contiguous gene deletion syndrome. We report a young woman with a de novo germline 9p21 microdeletion involving the CDKN2A/CDKN2B genes, who developed six primary cancers since childhood, including a very rare extraskeletal osteosarcoma (eOS) at the age of 8. To our knowledge this is the first report of eOS in a patient with CDKN2A/CDKN2B deletion.

Co-occurrence of CDKN2A/B and IFN-I homozygous deletions correlates with an immunosuppressive phenotype and poor prognosis in lung adenocarcinoma.

Homozygous deletion (HD) of CDKN2A and CDKN2B (CDKN2A/BHD ) is the most frequent copy-number variation (CNV) in lung adenocarcinoma (LUAD). CDKN2A/BHD has been associated with poor outcomes in LUAD; however, the mechanisms of its prognostic effect remain unknown. We analyzed genome, transcriptome, and clinical data from 517 patients with LUAD from the Cancer Genome Atlas (TCGA) and from 788 primary LUAD tumor and matched control samples from the MSK-IMPACT clinical cohort. CDKN2A/BHD was present in 19.1% of the TCGA-LUAD cohort and in 5.7% of the MSK-IMPACT cohort. CDKN2A/BHD patients had shorter disease-free survival and overall survival compared with CDKN2A/BWT individuals in both cohorts. Differences in clinical features did not influence the outcomes in the CDKN2A/BHD population. Mutation analyses showed that overall tumor mutational burden and mutations in classical drivers such as EGFR and RB1 were not associated with CDKN2A/BHD . In contrast, homozygous deletion of type I interferons (IFN-IHD ) frequently co-occurred with CDKN2A/BHD . CDKN2A/B and IFN-I are co-located in the same p21.3 region of chromosome 9. The co-occurrence of CDKN2A/BHD and IFN-IHD was not related to whole-genome doubling, chromosome instability, or aneuploidy. Patients with co-occurring CDKN2A/BHD and IFN-IHD had shorter disease-free survival and overall survival compared with CDKN2A/BWT patients. CDKN2A/BHD IFN-IHD had downregulated several key immune response pathways, suggesting that poor prognosis in CDKN2A/BHD LUAD could potentially be attributed to an immunosuppressive tumor microenvironment as a result of IFN-I depletion.

Effect of Sodium Butyrate on p16INK4a, p14ARF, p15INK4b, Class I HDACs (HDACs 1, 2, 3) Class II HDACs (HDACs 4, 5, 6), Cell Growth Inhibition and Apoptosis Induction in Pancreatic Cancer AsPC-1 and Colon Cancer HCT-116 Cell Lines.

BACKGROUND: In higher eukaryotes, cell-cycle transitions are regulated by different cyclin-dependent kinases (Cdks) and Cdk inhibitors (CKIs). CKIs include two groups, the Ink4 (p16INK4a, p15INK4b, p18INK4c, and p19INK4d) and the Cip/Kip (p21Cip1, p27Kip1, and p57Kip2) families. The hyperactivity of histone deacetylases (HDACs) is associated with cancer induction. Histone deacetylase inhibitors (HDACIs) such as sodium butyrate (NaBT) can inhibit HDAC activity resulting in apoptosis induction. The present study was designed to investigate the effect of sodium butyrate on p16INK4a, p14ARF, p15INK4b, class I HDACs (HDACs 1, 2, 3), and class II HDACs (HDACs 4, 5, 6), cell growth inhibition, and apoptosis induction in pancreatic cancer AsPC-1 and colon cancer HCT-116 cell lines. In fact, we want to know whether sodium butyrate can reactivate Ink4 and Cip/Kip families by HDACs inhibition. MATERIALS AND METHODS: The AsPC-1 and HCT-116 cells were treated with sodium butyrate at different periods. Then, the MTT assay, cell apoptosis assay, and qRT-PCR were done to determine viability, apoptosis, and the relative expression level of the genes respectively. RESULTS: The sodium butyrate increased p16INK4a, p14ARF, and p15INK4b and decreased class I and II HDACs significantly. Besides, HCT-116 cell was more sensitive to sodium butyrate in comparison to AsPC-1 cell. CONCLUSION: The sodium butyrate can reactivate the p16INK4a, p14ARF, and p15INK4b through inhibition of HDACs in AsPC-1 and HCT-116 cell lines.

DNMT1-Mediated DNA Methylation Targets CDKN2B to Promote the Repair of Retinal Ganglion Cells in Streptozotocin-Induced Mongolian Gerbils during Diabetic Retinopathy.

Objective: DNA methylation played a vital role in the progression of diabetic retinopathy. In this study, we aimed to explore the role of DNA cytosine-5-methyltransferase 1 (DNMT1) in the development of early diabetic retinopathy and its potential underlying mechanism. Methods: Eight-week-old healthy Mongolian gerbils were used to establish type 1 diabetes using streptozotocin (STZ). Alteration of weight, fasting blood glucose, density of RGCs (Tuj1-labeled), and H&E-stained retinal cross sections were applied to evaluate the diabetic retinopathy mouse model. The global DNA methylation level of the retina at different time points after STZ injection was measured using the global methylation assay. Western blot was used to detect the protein expression of DNMT1, DNA methyltransferase 3A (DNMT3A), and 3B (DNMT3B). Quantitative reverse transcription-polymerase chain reactions (qRT-PCR) and western blot were used to determine the expression of CDKN2B. Cell proliferation and cell cycle were evaluated by the MTS assay and flow cytometry. Results: STZ injection caused the increased global DNA methylation level, which reached a maximum at 6 weeks after injection. Moreover, STZ injection caused the damage of RGCs. At 6 weeks after STZ injection, the expression levels of DNMT1 and DNMT3B were significantly increased in the STZ group. DNMT1-induced DNA hypermethylation inhibited the expression of CDKN2B (a negative regulator of cell cycle). DNMT1-mediated DNA methylation facilitated RGC proliferation via regulating the expression of CDKN2B. Conclusion: DNMT1-mediated DNA methylation played an important role in STZ-induced diabetic retinopathy via modulating CDKN2B expression.

Genomic alterations drive metastases formation in pancreatic ductal adenocarcinoma cancer: deciphering the role of CDKN2A and CDKN2B in mediating liver tropism.

Metastases are often the direct cause of death from pancreatic ductal adenocarcinoma (PDAC). The role of genomic alterations (GA) in mediating tropism and metastasis formation by PDAC cells is currently unknown. We aimed to identify GAs predisposing colonization of PDAC cells to the liver and decipher mechanisms enabling this process. In order to reveal specific genes, we studied the frequency of GA in 8,880 local and 7,983 metastatic PDAC samples. We observed differential pattern of GA in the local tumor and specific metastatic sites, with liver metastases characterized by deletion of CDKN2A/B (encoding p16/p15, respectively). The role of CDKN2A/B in promoting liver metastasis was evidenced by enhanced tumorigenic phenotype of p15/p16-deleted PDAC cells when exposed to hepatocytes conditioned media. The liver is characterized by high-ammonia low-glutamine environment and transcriptomic assays indicated unique adaptation of PDAC cells to these conditions, including regulation of genes leading to reduced glutaminolysis, like overexpression of GLUL and reduction in GLS2. Furthermore, metabolic assays indicated an increase in glutamate derived from [U-13C]-glucose in p15/p16-deleted cells. Importantly, these cells thrived under high ammonia condition. These data suggest a unique role for genomic alterations in mediating tropism of PDAC. Among these alterations, p15/16 deletion was identified as a promoter of liver metastases. Further studies indicated a unique role for p15/16 in regulating glutaminolysis. These findings reveal vulnerabilities in PDAC cells, which may pave the way for the development of novel therapeutic strategies aiming at the prevention of liver metastases formation.

Methylation patterns of the CDKN2B and CDKN2A genes in an indigenous population exposed to pesticides.

The INK4-ARF locus includes the CDKN2B and CDKN2A genes and is functionally relevant in the regulation of both cell proliferation and senescence. Studies have reported modifications of DNA methylation in this locus by exposure to environmental contaminants including pesticides; however, until now, specific methylation profiles have not been reported in genetically conserved populations exposed to occupational pesticides. The aim of this study was to determine the methylation profiles of the CDKN2B and CDKN2A genes in a genetically conserved population exposed to pesticides. A cross-sectional and analytical study was carried out in 190 Huichol indigenous persons. Information related to pesticide exposure, diet and other variables were obtained through the use of a structured questionnaire. Blood and urine samples were collected for methylation test and dialkylphosphates (DAP) determination, respectively. DNA methylation was measured by the pyrosequencing of bisulfite-treated DNA and DAP concentrations by gas chromatography-tandem mass spectrometry (GC/MS). The most frequent metabolite in the population was dimethylthiophosphate. The farmer group presented a higher methylation percentage of CDKN2B than the non-farmer group, but no differences in CDKN2A were observed between groups. A positive correlation between methylation of CpG site 3 of CDKN2B and time working in the field was observed in the farmer group. An association between methylation percentage of CDKN2B and age was also observed in the non-farmer group. These results suggest that pesticide exposure and exposure time in Huichol indigenous individuals could modify the methylation pattern of the CDKN2B gene.