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MCL1 is a member of the BCL2 family of apoptosis regulators, which play a critical role in promoting cancer survival and drug resistance. We previously described PRT1419, a potent, MCL1 inhibitor with anti-tumor efficacy in various solid and hematologic malignancies. To identify novel biomarkers that predict sensitivity to MCL1 inhibition, we conducted a gene essentiality analysis using gene dependency data generated from CRISPR/Cas9 cell viability screens. We observed that clear cell renal cancer (ccRCC) cell lines with damaging PBRM1 mutations displayed a strong dependency on MCL1. PBRM1 (BAF180), is a chromatin-targeting subunit of mammalian pBAF complexes. PBRM1 is frequently altered in various cancers particularly ccRCC with ~40% of tumors harboring damaging PBRM1 alterations. We observed potent inhibition of tumor growth and induction of apoptosis by PRT1419 in various preclinical models of PBRM1-mutant ccRCC but not PBRM1-WT. Depletion of PBRM1 in PBRM1-WT ccRCC cell lines induced sensitivity to PRT1419. Mechanistically, PBRM1 depletion coincided with increased expression of pro-apoptotic factors, priming cells for caspase-mediated apoptosis following MCL1 inhibition. Increased MCL1 activity has been described as a resistance mechanism to Sunitinib and Everolimus, two approved agents for ccRCC. PRT1419 synergized with both agents to potently inhibit tumor growth in PBRM1-loss ccRCC. PRT2527, a potent CDK9 inhibitor which depletes MCL1, was similarly efficacious in monotherapy and in combination with Sunitinib in PBRM1-loss cells. Taken together, these findings suggest PBRM1 loss is associated with MCL1i sensitivity in ccRCC and provide rationale for the evaluation of PRT1419 and PRT2527 for the treatment for PBRM1-deficient ccRCC. [ABSTRACT FROM AUTHOR]

ABSTRACTThe LMNA gene encoding lamin A/C is amplified in some clear cell renal cell carcinoma (ccRCC) samples. Our data showed that depletion of the tumor suppressor PBRM1 can upregulate lamin A/C levels, and lamin A/C could interact with PBRM1. However, the role of lamin A/C in ccRCC is not yet fully understood. Our functional assays showed that although the proliferation ability was slightly impaired after LMNA depletion, the migration and invasion of ccRCC cells were significantly inhibited. This suppression was accompanied by a reduction in MMP2, MMP9, AKT/p-AKT, and Wnt/β-catenin protein levels. Our data therefore suggest that lamin A/C, as an interaction partner of the tumor suppressor PBRM1, plays a crucial role in tumor invasion and metastasis in ccRCC.

The last decade has seen great advances in genomic profiling and prognosis-associated factors of clear cell renal cell carcinoma (RCC), the most common entity in kidney cancer. Following VHL, PBRM1, SETD2, BAP1, and KDM5C have been validated as the most common co-occurring gene mutations in clear cell RCC by multicenter studies. However, the morphological features of clear cell RCC with co-occurring gene mutations remain unclear. In this study, we presented 20 clear cell RCCs that underwent next-generation sequencing, of which 1 tumor was reclassified as ELOC -mutated RCC. PBRM1, SETD2, BAP1, and KDM5C were the most common mutations, following VHL. Morphologically, clear cell RCC with PBRM1 or KDM5C mutation usually displayed a low-grade pattern. Cystic changes and hyalinized stroma were often observed. The Ki67 index was <10%. These observations indicated good prognosis. However, mutated SETD2 may increase the malignancy of clear cell RCC with PBRM1 mutation. Two clear cell RCCs with mutated PBRM1 and SETD2 developed local or distant metastases. Clear cell RCC with BAP1 mutations always had high-grade patterns, and rhabdoid differentiation was also observed, indicating that BAP1 mutation was associated with poor outcomes. Papillary architecture was often a feature of BAP1 mutation, which is uncommon in clear cell RCC. PDL1 was positive in only one tumor with BAP1 mutation, and the positivity rate was limited to 5%. B7H3 was negative in all tumors. Morphologic findings in this small cohort may suggest why PBRM1 mutation does not correlate with decreased survival, whereas BAP1 mutation usually predicts poor outcomes. [ABSTRACT FROM AUTHOR]

MCL1 is a member of the BCL2 family of apoptosis regulators, which play a critical role in promoting cancer survival and drug resistance. We previously described PRT1419, a potent, MCL1 inhibitor with anti-tumor efficacy in various solid and hematologic malignancies. To identify novel biomarkers that predict sensitivity to MCL1 inhibition, we conducted a gene essentiality analysis using gene dependency data generated from CRISPR/Cas9 cell viability screens. We observed that clear cell renal cancer (ccRCC) cell lines with damaging PBRM1 mutations displayed a strong dependency on MCL1. PBRM1 (BAF180), is a chromatin-targeting subunit of mammalian pBAF complexes. PBRM1 is frequently altered in various cancers particularly ccRCC with ~40% of tumors harboring damaging PBRM1 alterations. We observed potent inhibition of tumor growth and induction of apoptosis by PRT1419 in various preclinical models of PBRM1-mutant ccRCC but not PBRM1-WT. Depletion of PBRM1 in PBRM1-WT ccRCC cell lines induced sensitivity to PRT1419. Mechanistically, PBRM1 depletion coincided with increased expression of pro-apoptotic factors, priming cells for caspase-mediated apoptosis following MCL1 inhibition. Increased MCL1 activity has been described as a resistance mechanism to Sunitinib and Everolimus, two approved agents for ccRCC. PRT1419 synergized with both agents to potently inhibit tumor growth in PBRM1-loss ccRCC. PRT2527, a potent CDK9 inhibitor which depletes MCL1, was similarly efficacious in monotherapy and in combination with Sunitinib in PBRM1-loss cells. Taken together, these findings suggest PBRM1 loss is associated with MCL1i sensitivity in ccRCC and provide rationale for the evaluation of PRT1419 and PRT2527 for the treatment for PBRM1-deficient ccRCC.

Summary: PBRM1 is frequently mutated in cancers of epithelial origin. How PBRM1 regulates normal epithelial homeostasis, prior to cancer initiation, remains unclear. Here, we show that PBRM1’s gene regulatory roles differ drastically between cell states, leveraging human skin epithelium (epidermis) as a research platform. In progenitors, PBRM1 predominantly functions to repress terminal differentiation to sustain progenitors’ regenerative potential; in the differentiation state, however, PBRM1 switches toward an activator. Between these two cell states, PBRM1 retains its genomic binding but associates with differential interacting proteins. Our targeted screen identified the E3 SUMO ligase PIAS1 as a key interactor. PIAS1 co-localizes with PBRM1 on chromatin to directly repress differentiation genes in progenitors, and PIAS1’s chromatin binding drastically diminishes in differentiation. Furthermore, SUMOylation contributes to PBRM1’s repressive function in progenitor maintenance. Thus, our findings highlight PBRM1’s cell-state-specific regulatory roles influenced by its protein interactome despite its stable chromatin binding.

DNA methylation and gene alternative splicing drive spermatogenesis. In screening DNA methylation markers and transcripts related to sperm motility, semen from three pairs of full-sibling Holstein bulls with high and low motility was subjected to reduced representation bisulphite sequencing. A total of 948 DMRs were found in 874 genes (gDMRs). Approximately 89% of gDMR-related genes harboured alternative splicing events, including SMAD2, KIF17, and PBRM1. One DMR in exon 29 of PBRM1 with the highest 5mC ratio was found, and hypermethylation in this region was related to bull sperm motility. Furthermore, alternative splicing events at exon 29 of PBRM1 were found in bull testis, including PBRM1-complete, PBRM1-SV1 (exon 28 deletion), and PBRM1-SV2 (exons 28–29 deletion). PBRM1-SV2 exhibited significantly higher expression in adult bull testes than in newborn bull testes. In addition, PBRM1 was localized to the redundant nuclear membrane of bull sperm, which might be related to sperm motility caused by sperm tail breakage. Therefore, the hypermethylation of exon 29 may be associated with the production of PBRM1-SV2 in spermatogenesis. These findings indicated that DNA methylation alteration at specific loci could regulate gene splicing and expression and synergistically alter sperm structure and motility.

Background: The nucleoside FF‐10502‐01, structurally similar to but with different biologic effects than gemcitabine, shows promising activity both alone and combined with cisplatin in preclinical gemcitabine‐resistant tumor models. We conducted an open‐label, single‐arm, 3 + 3 first‐in‐human trial to explore the safety, tolerability, and antitumor activity of FF‐10502‐01 in patients with solid tumors. Methods: Patients with inoperable metastatic tumors refractory to standard therapies were enrolled. Escalating intravenous FF‐10502‐01 doses (8–135 mg/m2) were administered weekly for 3 weeks in 28‐day cycles until progressive disease or unacceptable toxicity was observed. Three expansion cohorts were subsequently evaluated. Results: A phase 2 dose of 90 mg/m2 was determined after evaluating 40 patients. Dose‐limiting toxicities included hypotension and nausea. Phase 2a enrolled patients with cholangiocarcinoma (36), gallbladder cancer (10), and pancreatic/other tumors (20). Common adverse events were grade 1–2 rash, pruritus, fever, and fatigue. Grade 3 or 4 hematologic toxicities were observed at low incidences, including thrombocytopenia (5.1%) and neutropenia (2%). Confirmed partial responses (PRs) occurred in five patients with gemcitabine‐refractory tumors, including three with cholangiocarcinoma and one each with gallbladder and urothelial cancer. Median progression‐free and overall survival rates in patients with cholangiocarcinoma were 24.7 and 39.1 weeks, respectively. Prolonged progression‐free survival in patients with cholangiocarcinoma was associated with BAP1 and PBRM1 mutations. Conclusion: FF‐10502‐01 was well tolerated with manageable side effects and limited hematologic toxicity. Durable PRs and disease stabilizations were observed in heavily pretreated biliary tract patients who had received prior gemcitabine. FF‐10502‐01 is distinct from gemcitabine and may represent an effective therapy. A phase 1/2a study of FF‐10502‐01, a nucleoside structurally similar to gemcitabine but with distinct biologic effects, demonstrates activity in patients with gemcitabine‐refractory tumors, including cholangiocarcinoma; this compares favorably to second‐line FOLFOX chemotherapy in patients with advanced biliary cancer. Prolonged progression‐free survival in cholangiocarcinoma was associated with BAP1 and PBRM1 mutations, which may be important for patient selection. [ABSTRACT FROM AUTHOR]

Malignant craniopharyngioma is especially rare, so the causes and genetic mutations associated with the malignant transformation have not been explained in detail. We investigated the molecular genetic characteristics of malignant transformation in craniopharyngioma. A 53-year-old man with a history of adamantinomatous craniopharyngioma presented with complaints of subcutaneous swelling. Magnetic resonance imaging showed a less enhanced intradural supra-sellar lesion and a heterogeneously well-enhanced extradural invasive lesion infiltrating the dura mater, brain, frontal bone, and subcutaneous tissue. Histopathological examination of the recurrent tumor revealed typical findings of both craniopharyngioma (intradural supra-sellar lesion) and malignant transformation, such as marked nuclear atypia with mitosis (invasive extradural lesion), which were not present in the primary tumor. A genetic panel test with the Oncopanel system was performed to investigate the genetic mutations responsible for the malignant transformation. Four genetic mutations were identified: CTNNB1 c.C98T, TP53 p.C135fs*35(PLS = 3 UPD/LOH), PBRM1 p.R1000*(PLS = 3 UPD/LOH), and BAP1 p.L650fs*5(PLS = 3 UPD/LOH). Sanger sequencing showed CTNNB1 in both the intradural supra-sellar and extradural invasive lesions, but TP53, PBRM1, and BAP1 only in the extradural invasive lesion. The genetic mutations of PBRM1 and BAP1 may be genetic factors in the malignant transformation of adamantinomatous craniopharyngioma. [ABSTRACT FROM AUTHOR]

Background: There has been evidence that Polybromo-1 (PBRM1) mutation was closely associated with immunotherapy response in clear cell renal cell carcinoma (ccRCC). However, it remains incompletely unclear whether PBRM1 mutations correlate with ICI response in pan-cancer.Methods: The clinical data and whole exome sequencing (WES) data were collected from seven published immunotherapy studies to evaluate the association between PBRM1 mutation and ICIs efficacy in the discovery cohort. In order to provide further insight into the relationship between PBRM1 and immunity, we analyzed a relatively large sample as a validation cohort. Moreover, we also collected the clinical data and mutation information of 134 non-small cell lung cancer (NSCLC) patients from the First Affiliated Hospital of Nanjing Medical University to verify the findings. Gene set enrichment analysis (GSEA) was used to evaluate the relationship between PBRM1 and immune-related pathway.Results: Our results found that PBRM1 mutation were associated with immune response in the discovery cohort (Progression free survival [PFS]: hazard ratio (HR) = .51, 95% CI: .28–.95, p = .030; objective response rate [ORR]: 47.92% vs. 28.21%, p = .0044; disease control rate [DCR]: 72.92% vs. 47.53%, p = .0008). In the validation cohort, the patients with PBRM1 mutation had a longer overall survival (OS) (hazard ratio = .69, 95% CI: .53–.91, p = .006). In our non-small cell lung cancer cohort, PFS, objective response rate and disease control rate had obvious superiority in the patients with PBRM1 mutation than those without PBRM1 mutation (PFS: HR = .268, 95% CI: 084–.854, p = .04, ORR: 55.56% vs. 20.00%, p = .027, DCR: 100% vs. 75.20%). Using the Gene set enrichment analysis (GSEA) in TCGA cohorts, PBRM1 mutation was closely related to immune efficacy and immune microenvironment, including killer cell mediated immunity regulation, cell cytokine production, CD8+ T-cell activation and MHC protein binding process.Conclusion: There is a strong correlation between PBRM1 mutation and prognosis and immune response. Based on the findings, PBRM1 mutation may be a promising immunotherapeutic signature that could guide clinical management and personalized immunotherapy.

In clear cell renal cell carcinoma (ccRCC), the von Hippel-Lindau tumor suppressor gene/hypoxia inducible factor (VHL/HIF) axis lays the groundwork for tumorigenesis and is the target of many therapeutic agents. HIF activation alone, however, is largely insufficient for kidney tumor development, and secondary mutations in PBRM1, BAP1, SETD2, KDM5C, or other tumor suppressor genes are strong enablers of tumorigenesis. Interestingly, it has been discovered that VHL loss and subsequent HIF activation results in upregulation of a negative feedback loop mediated by ISGF3, a transcription factor activated by type I interferon (IFN). Secondary mutations in the aforementioned tumor suppressor genes all partially disable this negative feedback loop to facilitate tumor growth. The convergence of several cancer genes on this pathway suggests that it plays an important role in ccRCC development and maintenance. Tumors with secondary mutations that dampen the negative feedback loop may be exquisitely sensitive to its reactivation, and pharmacological activation of ISGF3 either alone or in combination with other therapies could be an effective method to treat patients with ccRCC. In this review, we examine the relevance of the type I IFN pathway to ccRCC, synthesize our current knowledge of the ccRCC tumor suppressors in its regulation, and explore how this may impact the future treatment of patients with ccRCC. [ABSTRACT FROM AUTHOR]

Background: Due to its rarity, duodenal papillary carcinoma (DPC) is seldom studied as a unique disease and no specific molecular features or treatment guidelines are provided. Methods: Whole‐exome sequencing was performed to gain new insights into the DPC mutation landscape and to identify potential signalling pathways and therapeutic targets. Mechanistically, immunohistochemistry (IHC), immunofluorescence, RNA‐seq, ATAC‐seq and in vitro cell function experiments were performed to confirm the underlying mechanisms. Results: We described the mutational landscape of DPC for the first time as a group of rare tumours with a high frequency of dysregulation in the chromatin remodelling pathway, particularly PBRM1‐inactivating mutations that are significantly higher than duodenal adenocarcinomas and ampullary adenocarcinoma (27% vs. 0% vs. 7%, p <.01). In vitro cell experiments showed that downregulation of PBRM1 expression could significantly promote the cancer progression and epithelial‐to‐mesenchymal transition via the PBRM1‐c‐JUN‐VIM axis. The IHC data indicated that PBRM1 deficiency (p =.047) and c‐JUN expression (p <.001) were significantly associated with poor prognosis. Meanwhile, the downregulation of PBRM1 expression in HUTU‐80 cells was sensitive to radiation, which may be due to the suppression of c‐JUN by irradiation. Conclusions: Our findings define a novel molecular subgroup of PBRM1‐inactivating mutations in DPC. PBRM1 play an important role in DPC progression and may serve as a potential therapeutic target and prognostic indicator. [ABSTRACT FROM AUTHOR]

Abstract Alteration in the polybromo‐1 (PBRM1) protein encoding gene PBRM1 is the second most frequent mutation in clear cell renal cell carcinoma (ccRCC). It causes a series of changes in the tumorigenesis, progression, prognosis, and immune response of ccRCC patients. This study explored the PBRM1‐associated immunological features and identified the immune‐related genes (IRGs) linked to PBRM1 mutation using bioinformatics methods. A total of 37 survival IRGs associated with PBRM1 mutation in ccRCC patients were identified. To further explore the role of these IRGs in ccRCC and their association with immune status, eight IRGs with remarkable potential as individual targets were selected. An immune model that was constructed showed good performance in stratifying patients into different subgroups, showing clinical application potential compared to traditional clinical factors. Patients in the high‐risk group were inclined to have more advanced stage and higher grade tumors with node metastasis, distant metastasis, and poorer prognosis. Furthermore, these patients had high percentages of regulatory T cells, follicular helper T cells, and M0 macrophages and exhibited high expression levels of immune checkpoints proteins, such as CTLA‐4, PD‐1, LAG‐3, TIGIT, and CD47. Finally, a nomogram integrating the model and clinical factors for clinical application showed a more robust predictive performance for prognosis. The prediction model associated with PBRM1 mutation status and immunity can serve as a promising tool to stratify patients depending upon their immune status, thus facilitating immunotherapy in the future.

The oncogenic MUC1-C protein drives dedifferentiation of castrate resistant prostate cancer (CRPC) cells in association with chromatin remodeling. The present work demonstrates that MUC1-C is necessary for expression of IFNGR1 and activation of the type II interferon-gamma (IFN-γ) pathway. We show that MUC1-C→ARID1A/BAF signaling induces IFNGR1 transcription and that MUC1-C-induced activation of the NuRD complex suppresses FBXW7 in stabilizing the IFNGR1 protein. MUC1-C and NuRD were also necessary for expression of the downstream STAT1 and IRF1 transcription factors. We further demonstrate that MUC1-C and PBRM1/PBAF are necessary for IRF1-induced expression of (i) IDO1, WARS and PTGES, which metabolically suppress the immune tumor microenvironment (TME), and (ii) the ISG15 and SERPINB9 inhibitors of T cell function. Of translational relevance, we show that MUC1 associates with expression of IFNGR1, STAT1 and IRF1, as well as the downstream IDO1, WARS, PTGES, ISG15 and SERPINB9 immunosuppressive effectors in CRPC tumors. Analyses of scRNA-seq data further demonstrate that MUC1 correlates with cancer stem cell (CSC) and IFN gene signatures across CRPC cells. Consistent with these results, MUC1 associates with immune cell-depleted “cold” CRPC TMEs. These findings demonstrate that MUC1-C integrates chronic activation of the type II IFN-γ pathway and induction of chromatin remodeling complexes in linking the CSC state with immune evasion.

Abstract Background Due to its rarity, duodenal papillary carcinoma (DPC) is seldom studied as a unique disease and no specific molecular features or treatment guidelines are provided. Methods Whole‐exome sequencing was performed to gain new insights into the DPC mutation landscape and to identify potential signalling pathways and therapeutic targets. Mechanistically, immunohistochemistry (IHC), immunofluorescence, RNA‐seq, ATAC‐seq and in vitro cell function experiments were performed to confirm the underlying mechanisms. Results We described the mutational landscape of DPC for the first time as a group of rare tumours with a high frequency of dysregulation in the chromatin remodelling pathway, particularly PBRM1‐inactivating mutations that are significantly higher than duodenal adenocarcinomas and ampullary adenocarcinoma (27% vs. 0% vs. 7%, p

Under static condition, the pool size of peripheral invariant natural killer T (iNKT) cells is determined by their homeostatic proliferation, survival and thymic input. However, the underlying mechanism is not fully understood. In the present study, we found that the percentage and number of iNKT cells were significantly reduced in the spleen, but not in the thymus of mice with deletion of polybromo‐1 (Pbrm1) compared to wild type (WT) mice. Pbrm1 deletion did not affect iNKT cell proliferation and survival, instead significantly impaired their development from stage 1 to stage 2. Importantly, loss of Pbrm1 led to a dysfunction of RORγt expression and iNKT17 cell differentiation, but not iNKT1 and iNKT2 proportion. Collectively, our study reveals a novel mechanism of Pbrm1 controlling the peripheral size of iNKT cells through regulating their development and differentiation. [ABSTRACT FROM AUTHOR]

Background: PBRM1 gene abnormalities were recently found to play a role in tumor development and tumor immune activity. This article will explore the clinicopathological and molecular changes and tumor immune activity of the abnormal SWI/SNF complex subunit PBRM1 in gastric adenocarcinoma (GAC) and its significance.Methods: The cBioPortal, LinkedOmics and TISIDB datasets were used to analyze the abnormality of the PBRM1 gene in GAC and its relationship with prognosis, related molecular changes and tumor-infiltrating lymphocytes (TILs). In addition, 198 GAC cases were collected to further study the relationship between the loss/attenuation of PBRM1 expression and clinicopathology, prognosis, microsatellite stability, PD-L1 expression and TIL in GAC. DNA whole-exome sequencing was performed on 7 cases of gastric cancer with loss of PBRM1 expression.Results: The cBioPortal data showed that PBRM1 deletion/mutation accounted for 7.32% of GAC and was significantly associated with several molecular changes, such as molecular subtypes of GAC. The LinkedOmics dataset showed that PBRM1 mutation and its promoter DNA methylation showed lower PBRM1 mRNA expression, and PBRM1 mutation cases showed significantly higher mRNA expression of PD-L1 (CD274). TISIDB data showed that PBRM1 abnormalities were significantly positively associated with multiple TILs. In our group of 198 cases, the loss/attenuation of PBRM1 expression was significantly positively correlated with intra-tumoral tumor infiltrating lymphocytes (iTILs) and deficient MMR and PD-L1 expression. Kaplan–Meier survival analysis showed that the overall survival of GAC patients with loss/attenuation of PBRM1 expression was significantly better (p = 0.023). iTIL was an independent prognostic factor of GAC. Loss of PBRM1 expression often co-occurs with mutations in other SWI/SNF complex subunit genes, and there are some repetitive KEGG signaling changes.Conclusion: Abnormality of the PBRM1 gene may be related to the occurrence of some GACs and can affect tumor immune activity, thereby affecting clinicopathology and prognosis. It may be a potentially effective predictive marker for immunotherapy and a novel therapeutic approach associated with synthetic lethality.

Immune checkpoint inhibitors (ICIs) have become key agents in the management of clear cell renal cell carcinoma (ccRCC), but their benefits are limited and responders remain unidentified. We investigated the significance of PARP1 in ccRCC using RNA sequencing data for 311 tumors from patients enrolled in prospective clinical trials of PD-1 blockade. Among patients treated with nivolumab (n = 181), overall survival (OS) was significantly higher in the PARP1-low group than in the PARP1-high group (p = 0.006), and PARP1 status was significantly associated with OS (hazard ratio [HR] 1.7; p = 0.007). By contrast, for patients treated with everolimus (n = 130) there was no significant difference by PARP1 status for progression-free survival (PFS; p = 0.9) or OS (p = 0.38). In subgroup analysis for PBRM1 -mutated ccRCC, PFS (p = 0.016) and OS (p = 0.004) were significantly longer in the group with PARP1-low status and PBRM1 mutation in comparison to the other groups. In addition, PARP1 status was significantly associated with PFS (HR 2.6; p = 0.007) and OS (HR 3.5; p = 0.016) among patients with PBRM1 -mutated ccRCC treated with nivolumab. Our study suggests that PARP1 can be used as a biomarker for predicting response to ICI treatment for patients with PBRM1 -mutated ccRCC. Immune checkpoint inhibitors (ICIs) are key agents in the treatment of multiple cancers. We found that expression of the PARP1 protein was associated with survival after ICI treatment and with the response to ICI treatment in patients with clear cell kidney cancer who have a mutation of the PBRM1 gene. PARP1 expression is associated with survival following immune check point inhibitor (ICI) treatment. Moreover, clear cell renal carcinoma with PBRM1 mutation might be a good candidate for combination therapy with PARP inhibition and ICI. [ABSTRACT FROM AUTHOR]

Abstract Background Genomic studies of high-grade/progressive meningiomas have reported a heterogeneous mutation spectrum, identifying few recurrently mutated genes. Most studies have been underpowered to detect genomic subclasses of aggressive meningiomas due to relatively small number of available samples. Here, we present a genomic survey of one of the largest multi-institutional cohorts of high-grade/progressive meningiomas to date. Methods 850 high-grade/progressive meningiomas, including 441 WHO grade 2 and 176 WHO grade 3 meningiomas and 220 progressive WHO grade 1 meningiomas, were tested as part of a clinical testing program by hybridization capture of 406 cancer-related genes to detect base substitutions, indels, amplifications, deletions, and rearrangements. Information from pathology reports, histopathology review, and patient clinical data was assessed. Results Genomic analyses converged to identify at least three distinct patterns of biologically-aggressive meningiomas. The first and most common contained NF2-mutant tumors (n = 426, 50%), was associated with male sex (64.4% %, p = 0.0001) and often harbored additional mutations in CDKN2A/B (24%), and the chromatin regulators ARID1A (9%), and KDM6A (6%). A second group (NF2-agnostic) featured TERT promoter (TERTp; n = 56) or TP53 mutations (n = 25) and were either NF2-mutant or wild-type, and displayed no association with either sex (p = 0.39). The remaining group generally lacked NF2 mutations, and accounted for 40% of the cases—with three subgroups. One consistent primarily of grade 3 lesions harboring alterations in chromatin regulators BAP1 (n = 22) or PBRM1 (n = 16). A second subgroup contained AKT1 (n = 26), PIK3CA (n = 14) and SMO (n = 7) mutant skull-based meningiomas, and a third mixed subgroup included 237 meningiomas with a heterogeneous spectrum of low frequency and non-recurrent alterations. Conclusions Our findings indicate that the patterns of genomic alterations in high-grade/progressive meningiomas commonly group into three different categories. The most common NF2-associated canonical group frequently harbored CDKN2A/B alterations, which is potentially amenable to targeted therapies. An NF2-agnostic group harbored frequent TERTp and TP53 mutations. The final subclass, distinct from the canonical NF2 mutant associated pathway, was partly characterized by BAP1/PBRM1 alterations (rhabdoid/papillary histology) or skull-base disease. Overall, these data increase our understanding of the pathobiology of high-grade/progressive meningiomas and can guide the design of clinical trials. IRB approval status Reviewed and approved by Western IRB; Protocol No. 20152817.

Alteration in the polybromo‐1 (PBRM1) protein encoding gene PBRM1 is the second most frequent mutation in clear cell renal cell carcinoma (ccRCC). It causes a series of changes in the tumorigenesis, progression, prognosis, and immune response of ccRCC patients. This study explored the PBRM1‐associated immunological features and identified the immune‐related genes (IRGs) linked to PBRM1 mutation using bioinformatics methods. A total of 37 survival IRGs associated with PBRM1 mutation in ccRCC patients were identified. To further explore the role of these IRGs in ccRCC and their association with immune status, eight IRGs with remarkable potential as individual targets were selected. An immune model that was constructed showed good performance in stratifying patients into different subgroups, showing clinical application potential compared to traditional clinical factors. Patients in the high‐risk group were inclined to have more advanced stage and higher grade tumors with node metastasis, distant metastasis, and poorer prognosis. Furthermore, these patients had high percentages of regulatory T cells, follicular helper T cells, and M0 macrophages and exhibited high expression levels of immune checkpoints proteins, such as CTLA‐4, PD‐1, LAG‐3, TIGIT, and CD47. Finally, a nomogram integrating the model and clinical factors for clinical application showed a more robust predictive performance for prognosis. The prediction model associated with PBRM1 mutation status and immunity can serve as a promising tool to stratify patients depending upon their immune status, thus facilitating immunotherapy in the future. [ABSTRACT FROM AUTHOR]

PBRM1 appears as a tumor suppressor gene in a variety of tumors. The value of PBRM1 mutation or expression is different for the prognosis prediction of different kinds of tumors. Studies have revealed that JAK/STAT3, PBRM1/RLR and other signals were participated in the process of PBRM1 activating immune system, inflammatory responses and the transform of inflammation to cancer. This process modified the sensitivity of the patients to biological targeted therapy and immune checkpoint therapy. The combination of immune checkpoint inhibitor and targeted drug is the develop trends of cancer therapy in the future. In this review, we discuss the role of PBRM1 in the prognosis guidance of patients with different tumors, and explain the importance of PBRM1 detection in guiding the selection of drugs and treatment strategies and evaluating the efficacy.

The incessant interactions between susceptible humans and their respective macro/microenvironments registered throughout their lifetime result in the ultimate manifestation of individual cancers. With the average lifespan exceeding 50 years of age in humans since the beginning of 20th century, aging – the “time” factor – has played an ever-increasing role alongside host and environmental factors in cancer incidences. Cancer is a genetic/epigenetic disease due to gain-of-function mutations in cancer-causing genes (oncogene; OG) and/or loss-of-function mutations in tumor-suppressing genes (tumor suppressor genes; TSG). In addition to their integral relationship with cancer, a timely deployment of specific OG and/or TSG is in fact needed for higher organisms like human to cope with respective physiological and pathological conditions. Over the past decade, extensive human kidney cancer genomics have been performed and novel mouse models recapitulating human kidney cancer pathobiology have been generated. With new genomic, genetic, mechanistic, clinical and therapeutic insights accumulated from studying clear cell renal cell carcinoma (ccRCC)–the most common type of kidney cancer, we conceived a cancer evolution model built upon the OG-TSG signaling pair analogous to the electrical circuit breaker (CB) that permits necessary signaling output and at the same time prevent detrimental signaling overdrive. Hence, this viewpoint aims at providing a step-by-step mechanistic explanation/illustration concerning how inherent OG-TSG CBs intricately operate in concert for the organism’s wellbeing; and how somatic mutations, the essential component for genetic adaptability, inadvertently triggers a sequential outage of specific sets of CBs that normally function to maintain and protect and individual tissue homeostasis.

Abstract Background Isocitrate dehydrogenase 1/2 (IDH1/2), BAP1, ARID1A and PBRM1 have been reported as the most frequent mutant genes in intrahepatic cholangiocarcinoma (ICC), and their relationships with clinicopathological features and prognosis were researched in this study. Methods We collected clinical data of 130 ICC patients from January 2012 to December 2017. The IDH1/2 mutation and loss of BAP1, ARID1A and PBRM1 expressions were detected by DNA sequencing or immunohistochemical methods, and histological subtype of ICCs was determined by hematoxylin-eosin, Alcian blue and S100P staining. Results IDH1/2 mutation was related to decreased preoperative serum total bilirubin (P = 0.039), ferritin (P = 0.000) and higher histological differentiation (P = 0.024), and was associated with prolonged disease-free survival (P = 0.009) and a trend toward increased overall survival (P = 0.126) in small duct type of ICCs. Immunohistochemical staining results of MsMab-1 were generally consistent with DNA sequencing for IDH1/2 mutant in ICCs (κ = 0.691). Only BAP1 expression loss was correlated to prolonged disease-free survival (P = 0.031) and overall survival (P = 0.041) in large duct type of ICCs. Conclusions IDH1/2 mutation is a favorable predictor and may be related to iron metabolism in small duct type of ICCs. Furthermore, we suggest that the detection of IDH1/2 mutation is indispensable to determine targeted therapy in small duct type ICCs, while it is not necessary in large duct of ICCs. MsMab-1 is a relatively effective multi-specific antibody against IDH1/2 mutant in ICCs. BAP1 expression loss was correlated with improved prognosis only in large duct type ICCs.

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma (RCC). The genomic landscape in Chinese ccRCC needs to be elucidated. Herein, we investigated the molecular features of Chinese ccRCC patients. Genomic profiling of DNA was performed through next-generation sequencing (NGS) in Chinese patients with ccRCC between January 2017 and March 2020. Clinical information including age, gender, and tumor histology was collected. Immunohistochemistry (IHC) staining for PD-L1 expression was performed using PD-L1 IHC 22C3 pharmDx assay or Ventana PD-L1 SP263 assay. Data analyses were performed using R 3.6.1. A total of 880 Chinese ccRCC patients who have undergone NGS were included in this study. The most common somatic alterations were detected in VHL (59.7%), PBRM1 (18.0%), SETD2 (12.2%), BAP1 (10.2%), and TP53 (9.4%). Compared with The Cancer Genome Atlas (TCGA) database, a higher mutation frequency of VHL (59.7% vs. 50.0%, p < 0.001) and TP53 (9.4% vs. 3.5%, p < 0.001) and a lower mutation frequency of PBRM1 (18.0% vs. 31.0%, p < 0.001) were found in the Chinese cohort. Of the 460 patients who were evaluated for PD-L1 expression, 139 (30.2%) had positive PD-L1 expression. The median tumor mutational burden (TMB) value was 4.5 muts/Mb (range, 0–46.0). Five (0.7%) patients were identified as microsatellite instability-high (MSI-H). Furthermore, 52 (5.9%) patients were identified to carry pathogenic or likely pathogenic germline mutations in 22 cancer predisposition genes. This is the first large-scale comprehensive genomic analysis for Chinese ccRCC patients, and these results might provide a better understanding of molecular features in Chinese ccRCC patients, which can lead to an improvement in the personalized treatment for these patients. [ABSTRACT FROM AUTHOR]

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma (RCC). The genomic landscape in Chinese ccRCC needs to be elucidated. Herein, we investigated the molecular features of Chinese ccRCC patients. Genomic profiling of DNA was performed through next-generation sequencing (NGS) in Chinese patients with ccRCC between January 2017 and March 2020. Clinical information including age, gender, and tumor histology was collected. Immunohistochemistry (IHC) staining for PD-L1 expression was performed using PD-L1 IHC 22C3 pharmDx assay or Ventana PD-L1 SP263 assay. Data analyses were performed using R 3.6.1. A total of 880 Chinese ccRCC patients who have undergone NGS were included in this study. The most common somatic alterations were detected in VHL (59.7%), PBRM1 (18.0%), SETD2 (12.2%), BAP1 (10.2%), and TP53 (9.4%). Compared with The Cancer Genome Atlas (TCGA) database, a higher mutation frequency of VHL (59.7% vs. 50.0%, p < 0.001) and TP53 (9.4% vs. 3.5%, p < 0.001) and a lower mutation frequency of PBRM1 (18.0% vs. 31.0%, p < 0.001) were found in the Chinese cohort. Of the 460 patients who were evaluated for PD-L1 expression, 139 (30.2%) had positive PD-L1 expression. The median tumor mutational burden (TMB) value was 4.5 muts/Mb (range, 0–46.0). Five (0.7%) patients were identified as microsatellite instability-high (MSI-H). Furthermore, 52 (5.9%) patients were identified to carry pathogenic or likely pathogenic germline mutations in 22 cancer predisposition genes. This is the first large-scale comprehensive genomic analysis for Chinese ccRCC patients, and these results might provide a better understanding of molecular features in Chinese ccRCC patients, which can lead to an improvement in the personalized treatment for these patients.

Summary: PBRM1, a subunit of the PBAF coactivator complex that transcription factors use to activate target genes, is genetically inactivated in almost all clear cell renal cell cancers (RCCs). Using unbiased proteomic analyses, we find that PAX8, a master transcription factor driver of proximal tubule epithelial fates, recruits PBRM1/PBAF. Reverse analyses of the PAX8 interactome confirm recruitment specifically of PBRM1/PBAF and not functionally similar BAF. More conspicuous in the PAX8 hub in RCC cells, however, are corepressors, which functionally oppose coactivators. Accordingly, key PAX8 target genes are repressed in RCC versus normal kidneys, with the loss of histone lysine-27 acetylation, but intact lysine-4 trimethylation, activation marks. Re-introduction of PBRM1, or depletion of opposing corepressors using siRNA or drugs, redress coregulator imbalance and release RCC cells to terminal epithelial fates. These mechanisms thus explain RCC resemblance to the proximal tubule lineage but with suppression of the late-epithelial program that normally terminates lineage-precursor proliferation.

Identifying biomarkers for metastatic renal cell carcinoma (mRCC) is an unmet need in actual immunotherapy era. Available data regarding chromosome 3p genes (i.e., VHL , PBRM1 , SETD2) mutations as potential predictors for therapy response is conflicting. We describe the impact of these mutations on clinical outcomes in mRCC patients treated with immune checkpoint inhibitor (ICI)-doublet or ICI/tyrosine kinase inhibitor (TKI) combinations. We performed a single-center retrospective analysis on mRCC patients treated with first line ICI/ICI or ICI/TKI. A multi-gene panel was used, allowing the amplification of 841 amplicons (54.93 kb, human reference sequence hg19/GRCh37) in the coding sequences of the following genes: ATM, BAP1, KDM5C, MET, MTOR, NF2, PBRM1, PIK3CA, PTEN, SETD2, SMARCB1, TP53, TSC1, TSC2, VHL. 18 patients undergoing ICI/ICI and ICI/TKI who had tumor tissue adequate for molecular analysis were included. Histology was 100% clear cell. IMDC risk was 50% intermediate, 33.4% good, 16.6% poor. First line therapy was 89% ICI/TKI, 11% ICI/ICI. 83.3% pts (n = 15) carried genomic alterations (GA). Most common GA included VHL in 44% (n = 8; 7 pathogenic - PAT and 1 variant of unknown significance - VUS), PBRM1 in 44% (n = 8; 5 PAT and 3 VUS) and SETD2 in 33% (n = 6; 4 PAT and 2 VUS). With the limit of a small sample that did not allow proper statistical analyses, SETD2 -mutated patients had lower median progression free (mPFS) and overall survival (mOS) than non- SETD2 mutated patients. Higher mPFS and mOS were shown with VHL or PBRM1 GA, especially in PBRM1 +VHL mutated pts. Our data shows a possible negative predictive role of SETD2 GA for ICI-based therapy in RCC. Concomitant VHL and PBRM1 GA could act as a predictor for ICI/TKI efficacy. Our hypothesis-generating analysis highlights the need of an integrated evaluation of these genes as promising biomarkers in RCC. Further larger studies are required. [ABSTRACT FROM AUTHOR]

The mammalian SWI/SNF chromatin remodelling complexes are commonly dysregulated in cancer. These complexes contribute to maintaining genome stability through a variety of pathways. Recent research has highlighted an important interplay between genome instability and immune signalling, and evidence suggests that this interplay can modulate the response to immunotherapy. Here, we review emerging studies where direct evidence of this relationship has been uncovered in SWI/SNF deficient cells. We also highlight genome maintenance activities of SWI/SNF that could potentially shape immune responses and discuss potential therapeutic implications. • The SWI/SNF complex maintains genome stability through multiple pathways, including DNA repair. • Mutations in genes encoding SWI/SNF subunits have been implicated in the response to immune checkpoint inhibitor therapy. • DNA damage responses influence immune pathway activity. • SWI/SNF deficiency could influence immune responses in cells through changes in genome stability and DNA damage responses. [ABSTRACT FROM AUTHOR]

Polybromo‐1 (PBRM1) is an important tumor suppressor in kidney cancer. It contains six tandem bromodomains (BDs), which are specialized structures that recognize acetyl‐lysine residues. While BD2 has been found to bind acetylated histone H3 lysine 14 (H3K14ac), it is not known whether other BDs collaborate with BD2 to generate strong binding to H3K14ac, and the importance of H3K14ac recognition for the molecular and tumor suppressor function of PBRM1 is also unknown. We discovered that full‐length PBRM1, but not its individual BDs, strongly binds H3K14ac. BDs 2, 4, and 5 were found to collaborate to facilitate strong binding to H3K14ac. Quantitative measurement of the interactions between purified BD proteins and H3K14ac or nonacetylated peptides confirmed the tight and specific association of the former. Interestingly, while the structural integrity of BD4 was found to be required for H3K14ac recognition, the conserved acetyl‐lysine binding site of BD4 was not. Furthermore, simultaneous point mutations in BDs 2, 4, and 5 prevented recognition of H3K14ac, altered promoter binding and gene expression, and caused PBRM1 to relocalize to the cytoplasm. In contrast, tumor‐derived point mutations in BD2 alone lowered PBRM1's affinity to H3K14ac and also disrupted promoter binding and gene expression without altering cellular localization. Finally, overexpression of PBRM1 variants containing point mutations in BDs 2, 4, and 5 or BD2 alone failed to suppress tumor growth in a xenograft model. Taken together, our study demonstrates that BDs 2, 4, and 5 of PBRM1 collaborate to generate high affinity to H3K14ac and tether PBRM1 to chromatin. Mutations in BD2 alone weaken these interactions, and this is sufficient to abolish its molecular and tumor suppressor functions.

Loss of the polybromo-1 (PBRM1) protein has been expected as a possible biomarker for clear cell renal cell carcinoma (ccRCC). There is little knowledge about how PBRM1 immunohistochemical expression correlates with the histomorphological features of ccRCC and the endothelial expression of tumor vasculature. The present study evaluates the association of architectural patterns with the PBRM1 expression of cancer cells using a cohort of 425 patients with nonmetastatic ccRCC. Furthermore, we separately assessed the PBRM1 expression of the endothelial cells and evaluated the correlation between the expression of cancer cells and endothelial cells. PBRM1 loss in cancer cells was observed in 148 (34.8%) patients. In the correlation analysis between architectural patterns and PBRM1 expression, macrocyst/microcystic, tubular/acinar, and compact/small nested were positively correlated with PBRM1 expression, whereas alveolar/large nested, thick trabecular/insular, papillary/pseudopapillary, solid sheets, and sarcomatoid/rhabdoid were negatively correlated with PBRM1 expression. PBRM1 expression in vascular endothelial cells correlated with the expression of cancer cells (correlation coefficient = 0.834, p < 0.001). PBRM1 loss in both cancer and endothelial cells was associated with a lower recurrence-free survival rate (p < 0.001). Our PBRM1 expression profile indicated that PBRM1 expression in both cancer and endothelial cells may be regulated in an orchestrated manner.

PBRM1 is frequently mutated in cancers of epithelial origin. How PBRM1 regulates normal epithelial homeostasis, prior to cancer initiation, remains unclear. Here, we show that PBRM1's gene regulatory roles differ drastically between cell states, leveraging human skin epithelium (epidermis) as a research platform. In progenitors, PBRM1 predominantly functions to repress terminal differentiation to sustain progenitors' regenerative potential; in the differentiation state, however, PBRM1 switches toward an activator. Between these two cell states, PBRM1 retains its genomic binding but associates with differential interacting proteins. Our targeted screen identified the E3 SUMO ligase PIAS1 as a key interactor. PIAS1 co-localizes with PBRM1 on chromatin to directly repress differentiation genes in progenitors, and PIAS1's chromatin binding drastically diminishes in differentiation. Furthermore, SUMOylation contributes to PBRM1's repressive function in progenitor maintenance. Thus, our findings highlight PBRM1's cell-state-specific regulatory roles influenced by its protein interactome despite its stable chromatin binding., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

The reader(s) for acetylated tumor antigen p53 remains elusive. Here, PBRM1 (polybromo-1) is identified as a reader for acetylated lysine382 on p53 through its bromodomain 4 (BD4). PBRM1 BD4 mutants fail to support p53 transcriptional activity and suppress tumor growth. Thus PBRM1 suppresses tumor growth through p53 in kidney cancer.

Background: Isocitrate dehydrogenase 1/2 (IDH1/2), BAP1, ARID1A and PBRM1 have been reported as the most frequent mutant genes in intrahepatic cholangiocarcinoma (ICC), and their relationships with clinicopathological features and prognosis were researched in this study.Methods: We collected clinical data of 130 ICC patients from January 2012 to December 2017. The IDH1/2 mutation and loss of BAP1, ARID1A and PBRM1 expressions were detected by DNA sequencing or immunohistochemical methods, and histological subtype of ICCs was determined by hematoxylin-eosin, Alcian blue and S100P staining.Results: IDH1/2 mutation was related to decreased preoperative serum total bilirubin (P = 0.039), ferritin (P = 0.000) and higher histological differentiation (P = 0.024), and was associated with prolonged disease-free survival (P = 0.009) and a trend toward increased overall survival (P = 0.126) in small duct type of ICCs. Immunohistochemical staining results of MsMab-1 were generally consistent with DNA sequencing for IDH1/2 mutant in ICCs (κ = 0.691). Only BAP1 expression loss was correlated to prolonged disease-free survival (P = 0.031) and overall survival (P = 0.041) in large duct type of ICCs.Conclusions: IDH1/2 mutation is a favorable predictor and may be related to iron metabolism in small duct type of ICCs. Furthermore, we suggest that the detection of IDH1/2 mutation is indispensable to determine targeted therapy in small duct type ICCs, while it is not necessary in large duct of ICCs. MsMab-1 is a relatively effective multi-specific antibody against IDH1/2 mutant in ICCs. BAP1 expression loss was correlated with improved prognosis only in large duct type ICCs. [ABSTRACT FROM AUTHOR]

Objective: PBRM1, located on 3p21, functions as a tumor suppressor and somatic mutation of PBRM1 is frequent in clear cell renal cell carcinoma (ccRCC). This study aims to determine the influence of PBRM1 expression on the prognosis of patients with mRCC receiving tyrosine kinase inhibitor (TKI) treatment. Methods: We identified 116 mRCC patients who were administered sunitinib or sorafenib as first-line therapy, between January 2006 and December 2016 at our institution. PBRM1 expression was assessed by immunohistochemistry. The Kaplan–Meier method was used to estimate the progression-free survival (PFS) and overall survival (OS), log-rank test was used to compare the survival outcomes between patients with low and high PBRM1 expression levels, and the Cox proportional hazard regression model was used to estimate the prognostic value. Prognostic accuracy was determined using Harrell concordance index, and nomograms were built to evaluate the prognosis of mRCC. Results: Patients with low PBRM1 expression had significantly shorter median PFS (9 vs 26 months, P < 0.001) and OS (21 vs 44 months, P < 0.001) than those with high expression. Multivariate analysis showed that PBRM1 expression was an independent predictor of PFS (HR 1.975, P = 0.013) and OS (HR 2.282, P = 0.007). The model built by the addition of PBRM1 improved the C-index of PFS and OS to 0.72 and 0.82, respectively. Conclusions: The expression of PBRM1 could be a significant prognostic factor for mRCC patients treated with targeted therapy, and it increases the prognostic accuracy of the established prognostic model. [ABSTRACT FROM AUTHOR]

PBRM1, a component of the chromatin remodeller SWI/SNF, is often deleted or mutated in human cancers, most prominently in renal cancers. Core components of the SWI/SNF complex have been shown to be important for the cellular response to hypoxia. Here, we investigated how PBRM1 controls HIF-1α activity. We found that PBRM1 is required for HIF-1α transcriptional activity and protein levels. Mechanistically, PBRM1 is important for HIF-1α mRNA translation, as absence of PBRM1 results in reduced actively translating HIF-1α mRNA. Interestingly, we found that PBRM1, but not BRG1, interacts with the m6A reader protein YTHDF2. HIF-1α mRNA is m6A-modified, bound by PBRM1 and YTHDF2. PBRM1 is necessary for YTHDF2 binding to HIF-1α mRNA and reduction of YTHDF2 results in reduced HIF-1α protein expression in cells. Our results identify a SWI/SNF-independent function for PBRM1, interacting with HIF-1α mRNA and the epitranscriptome machinery. Furthermore, our results suggest that the epitranscriptome-associated proteins play a role in the control of hypoxia signalling pathways.

PBRM1 is the second most commonly mutated gene after VHL in clear cell renal cell carcinoma (ccRCC). However, the biological consequences of PBRM1 mutations for kidney tumorigenesis are unknown. Here, we find that kidney-specific deletion of Vhl and Pbrm1, but not either gene alone, results in bilateral, multifocal, transplantable clear cell kidney cancers. PBRM1 loss amplified the transcriptional outputs of HIF1 and STAT3 incurred by Vhl deficiency. Analysis of mouse and human ccRCC revealed convergence on mTOR activation, representing the third driver event after genetic inactivation of VHL and PBRM1. Our study reports a physiological preclinical ccRCC mouse model that recapitulates somatic mutations in human ccRCC and provides mechanistic and therapeutic insights into PBRM1 mutated subtypes of human ccRCC.

DNA methylation and gene alternative splicing drive spermatogenesis. In screening DNA methylation markers and transcripts related to sperm motility, semen from three pairs of full-sibling Holstein bulls with high and low motility was subjected to reduced representation bisulphite sequencing. A total of 948 DMRs were found in 874 genes (gDMRs). Approximately 89% of gDMR-related genes harboured alternative splicing events, including SMAD2, KIF17 , and PBRM1 . One DMR in exon 29 of PBRM1 with the highest 5mC ratio was found, and hypermethylation in this region was related to bull sperm motility. Furthermore, alternative splicing events at exon 29 of PBRM1 were found in bull testis, including PBRM1-complete, PBRM1-SV1 (exon 28 deletion), and PBRM1-SV2 (exons 28-29 deletion). PBRM1-SV2 exhibited significantly higher expression in adult bull testes than in newborn bull testes. In addition, PBRM1 was localized to the redundant nuclear membrane of bull sperm, which might be related to sperm motility caused by sperm tail breakage. Therefore, the hypermethylation of exon 29 may be associated with the production of PBRM1-SV2 in spermatogenesis. These findings indicated that DNA methylation alteration at specific loci could regulate gene splicing and expression and synergistically alter sperm structure and motility.

The LMNA gene encoding lamin A/C is amplified in some clear cell renal cell carcinoma (ccRCC) samples. Our data showed that depletion of the tumor suppressor PBRM1 can upregulate lamin A/C levels, and lamin A/C could interact with PBRM1. However, the role of lamin A/C in ccRCC is not yet fully understood. Our functional assays showed that although the proliferation ability was slightly impaired after LMNA depletion, the migration and invasion of ccRCC cells were significantly inhibited. This suppression was accompanied by a reduction in MMP2, MMP9, AKT/p-AKT, and Wnt/β-catenin protein levels. Our data therefore suggest that lamin A/C, as an interaction partner of the tumor suppressor PBRM1, plays a crucial role in tumor invasion and metastasis in ccRCC.

Whereas VHL inactivation is a primary event in clear cell renal cell carcinoma (ccRCC), the precise mechanism(s) of how this interacts with the secondary mutations in tumor suppressor genes, including PBRM1, KDM5C/JARID1C, SETD2, and/or BAP1, remains unclear. Gene expression analyses reveal that VHL, PBRM1, or KDM5C share a common regulation of interferon response expression signature. Loss of HIF2α, PBRM1, or KDM5C in VHL-/-cells reduces the expression of interferon stimulated gene factor 3 (ISGF3), a transcription factor that regulates the interferon signature. Moreover, loss of SETD2 or BAP1 also reduces the ISGF3 level. Finally, ISGF3 is strongly tumor-suppressive in a xenograft model as its loss significantly enhances tumor growth. Conversely, reactivation of ISGF3 retards tumor growth by PBRM1-deficient ccRCC cells. Thus after VHL inactivation, HIF induces ISGF3, which is reversed by the loss of secondary tumor suppressors, suggesting that this is a key negative feedback loop in ccRCC.

Polybromo‐1 (PBRM1) is an important tumor suppressor in kidney cancer. It contains six tandem bromodomains (BDs), which are specialized structures that recognize acetyl‐lysine residues. While BD2 has been found to bind acetylated histone H3 lysine 14 (H3K14ac), it is not known whether other BDs collaborate with BD2 to generate strong binding to H3K14ac, and the importance of H3K14ac recognition for the molecular and tumor suppressor function of PBRM1 is also unknown. We discovered that full‐length PBRM1, but not its individual BDs, strongly binds H3K14ac. BDs 2, 4, and 5 were found to collaborate to facilitate strong binding to H3K14ac. Quantitative measurement of the interactions between purified BD proteins and H3K14ac or nonacetylated peptides confirmed the tight and specific association of the former. Interestingly, while the structural integrity of BD4 was found to be required for H3K14ac recognition, the conserved acetyl‐lysine binding site of BD4 was not. Furthermore, simultaneous point mutations in BDs 2, 4, and 5 prevented recognition of H3K14ac, altered promoter binding and gene expression, and caused PBRM1 to relocalize to the cytoplasm. In contrast, tumor‐derived point mutations in BD2 alone lowered PBRM1's affinity to H3K14ac and also disrupted promoter binding and gene expression without altering cellular localization. Finally, overexpression of PBRM1 variants containing point mutations in BDs 2, 4, and 5 or BD2 alone failed to suppress tumor growth in a xenograft model. Taken together, our study demonstrates that BDs 2, 4, and 5 of PBRM1 collaborate to generate high affinity to H3K14ac and tether PBRM1 to chromatin. Mutations in BD2 alone weaken these interactions, and this is sufficient to abolish its molecular and tumor suppressor functions. Bromodomains (BDs) 2, 4, and 5 of polybromo‐1 (PBRM1) were found to collaborate to facilitate strong binding to H3K14ac. Quantitative measurement confirmed this. Simultaneous point mutations in these bromodomains prevented recognition of H3K14ac, altered promoter binding and gene expression, and relocalized PBRM1 to the cytoplasm. In contrast, tumor‐derived point mutations in BD2 alone disrupted the molecular and tumor suppressor functions of PBRM1. [ABSTRACT FROM AUTHOR]

Abstract The human polybromo-1 protein (BAF180) is a known driver mutation in clear cell renal cell carcinoma, where it is mutated in approximately 40% of cases. BAF180 is the chromatin-targeting subunit of the PBAF complex. BAF180 has six bromodomains, two BAH domains, and one HMG box. Bromodomains are known to recognize acetylated-lysines on histones and play a role in nucleosome recognition. BAH domains are required for ubiquitination of PCNA, a key regulator of DNA damage. The putative HMG box, if functional, may be involved in DNA-binding. While the binding specificities of individual bromodomains have been studied by our lab and others, the results have failed to reach a consensus. The acetyl-histone binding features of the full-length protein is unknown and is the motivation for this work. The hypothetical HMG and BAH domains have not been studied and the actual function of these regions is currently unknown. Thus, the precise interactions of this large and complex protein are not well-studied. Advances in understanding this large protein have been hindered by the inability to express and purify recombinant full-length BAF180 protein. Currently, only phenomenological studies using BAF180 expressed in mammalian cells have been conducted. Here, we report the successful expression, purification of full-length biologically active BAF180 protein using the GAP promoter in the heterologous host Pichia pastoris. The ability to express full-length and mutated BAF180 will allow for biophysical binding studies. Knowledge of the binding interactions is critical for us to understand the role of BAF180 in cancer development and its progression. Highlights • First successful expression of full-length BAF180 in a recombinant system. • Confirmation of BAF180 presence with antibody. • Recombinant protein proves to be bioactive and bind modified histone peptides. [ABSTRACT FROM AUTHOR]

Abstract Background The prognostic value of PBRM1 expression in renal cell carcinoma (RCC) had been investigated in previous studies; however, the results remain inconclusive. We investigated the prognostic value and clinicopathological significance of PBRM1 protein expression in RCC. Methods PubMed, Embase, Web of Science, and Cochrane database were searched for studies investigating the relationships between PBRM1 expression and outcomes in RCC. Hazard ratios (HRs) for survival outcomes and odds ratios (ORs) for clinical parameters were extracted from eligible studies. Heterogeneity was assessed using the I2 value. The fixed-effects model was used if there was no evidence of heterogeneity; otherwise, the random-effects model was used. Publication bias was evaluated using Begg's funnel plots and Egger's regression test. Results A total of 2942 patients from 7 studies were included in the meta-analysis. The results showed that decreased expression of PBRM1 is associated with poor overall survival (OS) (HR = 2.11, 95% CI: 1.52–2.96), cancer-specific survival (CSS) (HR = 1.32, 95% CI: 1.10–1.58), and progression-free survival/ recurrence-free survival (PFS/RFS) (HR = 1.57, 95% CI : 1.34–1.85) in RCC. In addition, PBRM1 positive expression was significantly associated with earlier TNM stage (III/IV vs. I/II , OR = 0.53, 95% CI: 0.30–0.94), primary tumor stage (pT3/4 vs. pT1/2, OR = 0.32, 95% CI: 0.20–0.52), and Fuhrman grade (3/4 vs. 1/2, OR = 0.69, 95% CI: 0.46–1.02), but not related to Necrosis or Sex. Conclusions Decreased expression of PBRM1 is correlated with poor prognosis and advanced clinicopathological features in patients with RCC. Highlights • PBRM1 expression has been found to predict clinical outcomes in renal cell carcinoma (RCC). • We assessed the prognostic value of PBRM1 expression in RCC patients. • Decreased expression of PBRM1 predicted a poor OS, CSS, and PFS/RFS in patients with RCC. • Decreased expression of PBRM1 expression was correlated with advanced clinicopathological features in patients with RCC. • PBRM1 expression could serve as an indicator of the prognosis in patients with RCC. [ABSTRACT FROM AUTHOR]

Early mammalian development occurs during embryo transit of the female reproductive tract. Transport is orchestrated by secreted oviduct fluid, unidirectional beating of epithelial cilia, and smooth muscle contractions. Using gene-edited mice, we document that conditional disruption of a component of the SWI/SNF chromatin remodeling complex in smooth muscle cells prevents transport through the oviduct without perturbing embryogenesis. Analysis with RNA sequencing (RNA-seq), transposase-accessible chromatin with sequencing (ATAC-seq), chromatin immunocleavage sequencing (ChIC-seq), and pharmacologic rescue experiments implicated prostaglandin signaling pathways. In comparison with controls, gene-edited mice had compromised chromatin accessibility at enhancer/promoters of Ptgs2 , Pla2g16 , Pla2r1 , and Ptger3 (EP3) as well as decreased enhancer-promoter interactive looping critical for Ptgs2 (aka Cox-2) expression in a SWI/SNF complex-dependent manner. Treatment of wild-type mice with prostaglandin inhibitors phenocopied the genetically induced defect. [Display omitted] • Conditional disruption of SWI/SNF prevents embryo transport in the oviduct • SWI/SNF facilitates prostaglandin pathway in a chromatin-remodeling-dependent manner • Disrupted enhancer-promoter interactions of Cox-2 affects prostaglandin signaling • Phenotype can be reversed with exogenous prostaglandins and induced with inhibitor Xin et al. conditionally ablate Pbrm1 , a component of SWI/SNF, to prevent transit of mouse embryos through the reproductive tract without disrupting preimplantation development. The effect is attributed to compromised prostaglandin signaling in oviduct smooth muscle cells and can be reversed by administration of exogeneous prostaglandins or induced with inhibitors. [ABSTRACT FROM AUTHOR]

Background Radiogenomics is an emerging tool with applications in screening for molecular biomarkers in diagnostic and prognostic assessment through the extraction of quantitative data from medical images (Shui et al., Front Oncol 2021). In this study, we aim to develop machine learning (ML) models to predict the most common genomic alterations present in our subset of renal cell carcinoma patients (pts). Methods Retrospectively, pts with tissue genomic testing from CT-guided biopsy samples were identified. Genomic testing was done via GEM ExTra assay, a CAP-accredited, CLIA-certified test encompassing tumor whole exome sequencing and whole transcriptome sequencing (TGen; Phoenix, AZ). Biopsy sample collection sites were identified from pre-biopsy contrast CT images, and the lesions were segmented with ITK-SNAP software, from which 510 radiomic features were extracted with Pyradiomics. The Least Absolute Shrinkage and Selection Operator (LASSO) regression was used to select the most relevant features. Logistic regression (LR) and support vector machine (SVM) classifiers were built for the prediction of PBRM1, VHL, and SETD2 gene alterations. Multiple metrics were used to evaluate the predictive performance via leave-one-out cross-validation, including the area under the receiver operating characteristic (AUROC) and the area under the precision-recall curve (AUPRC). Feature importance was evaluated with Shapley additive explanations (SHAP) method. Results A total of 14 RCC pts (10:4 M:F) with genomic testing from CT-guided biopsies were identified. The majority of pts were White (85.7%) and had clear cell histology (71.4%). The most common locations for the CT-guided biopsy were lung (18.2%), soft tissue (13.6%), kidney (9.1%), and bone (9.1%). The most common alterations were seen in PBRM1 (50%), VHL (43.9%), and SETD2 (35.7%) genes. The PBRM1 gene was predicted with the highest AUROC (0.84) and AUPRC (0.88) with the SVM classifier, followed by the SETD2 gene (AUROC=0.78 and AUPRC=0.66) with LR classifier and VHL gene (AUROC=0.56 and AUPRC=0.65) with SVM classifier. Notably, all three models showed good sensitivity in classifying gene mutation status (PBRM1: 0.86; VHL: 0.88; SETD2: 0.89). Among all radiomic features, first-order features, Gray Level Size Zone Matrix features, and Gray Level Dependence Matrix features were found to be the most important features for predictions. Conclusions Using a CT-based radiomics analysis of the biopsy area, we showed that SVM and LR prediction models could predict PBRM1, VHL, and SETD2 mutations with high accuracy. These models may assist in identifying potentially actionable alterations and yield ease in treatment selection for RCC. Further extensive studies are warranted to validate our findings and improve our model. CDMRP DOD Funding: no [ABSTRACT FROM AUTHOR]

Purpose: Renal cell carcinoma (RCC) is genetically characterized by the recurrent loss of the short arm of chromosome 3. Classically, Von Hippel Lindau (VHL) was the only frequently mutated gene in RCC. Recently, several novel frequent mutations of histone modifying and chromatin remodeling genes, including PBRM1 and SETD2, were identified. In the present study, we aimed to determine the possible relationship between PBRM1 and SETD2 genes, and renal cell carcinoma by molecular techniques. Material and Methods: Screening possible mutation and determining mRNA expression level of PBRM1 and SETD2 genes in 20 pairs of tumor and normal samples of RCC patients were performed by nucleotide sequencer and reverse transcription- polymerase chain reaction (RT- PCR). Results: The mRNA expression levels of both genes were significantly reduced in tumor samples when compared with the control samples. As a result of mutational analysis, a single insertion nucleotide polymorphism in exon 12 of SETD2 gene was detected in one patient. Conclusion: Reduced mRNA expression level of PBRM1 and SETD2 might be risk factor for RCC development. Further analysis is warranted to investigate responsible genes rather than PBRM1 and SETD2 in RCC. [Cukurova Med J 2016; 41(1.000): 105-111]