Taspase1 was identified as the threonine endopeptidase that cleaves mixed-lineage leukemia (MLL) for proper

Therapeutic harnessing of adaptive immunity via checkpoint inhibition has transformed the treatment of many cancers. Despite unprecedented long-term responses, most patients do not respond to these therapies. Immunotherapy non-responders often harbor high levels of circulating myeloid-derived suppressor cells (MDSCs)-an immunosuppressive innate cell population. Through genetic and pharmacological approaches, we uncovered a pathway governing MDSC abundance in multiple cancer types. Therapeutic liver-X nuclear receptor (LXR) agonism reduced MDSC abundance in murine models and in patients treated in a first-in-human dose escalation phase 1 trial. MDSC depletion was associated with activation of cytotoxic T lymphocyte (CTL) responses in mice and patients. The LXR transcriptional target ApoE mediated these effects in mice, where LXR/ApoE activation therapy elicited robust anti-tumor responses and also enhanced T cell activation during various immune-based therapies. We implicate the LXR/ApoE axis in the regulation of innate immune suppression and as a target for enhancing the efficacy of cancer immunotherapy in patients.

Purpose To investigate the impact of newly identified chromosome 3p21 epigenetic tumor suppressors PBRM1, SETD2, and BAP1 on cancer specific survival (CSS) of 609 clear cell renal cell carcinoma (ccRCC) patients from two distinct cohorts. Patients and Methods Select sequencing on 3p tumor suppressors of 188 patients who underwent resection of primary ccRCC at the Memorial Sloan-Kettering Cancer Center (MSKCC) was performed to interrogate the genotype-phenotype associations. These findings were compared to analyses of the genomic and clinical dataset from our non-overlapping The Cancer Genome Atlas (TCGA) cohort of 421 primary ccRCC patients. Results 3p21 tumor suppressors are frequently mutated in both the MSKCC (PBRM1, 30.3%; SETD2, 7.4%; BAP1, 6.4%) and the TCGA (PBRM1, 33.5%; SETD2, 11.6%; BAP1, 9.7%) cohorts. BAP1 mutations are associated with worse CSS in both cohorts (MSKCC, p=0.002, HR 7.71 (2.08–28.6); TCGA, p=0.002, HR 2.21 (1.35–3.63)). SETD2 are associated with worse CSS in the TCGA cohort (p=0.036, HR 1.68 (1.04–2.73)). On the contrary, PBRM1 mutations, the second most common gene mutations of ccRCC, have no impact on CSS. Conclusion The chromosome 3p21 locus harbors three frequently mutated ccRCC tumor suppressor genes. BAP1 and SETD2 mutations (6–12%) are associated with worse CSS, suggesting their roles in disease progression. PBRM1 mutations (30–34%) do not impact CSS, implicating its principal role in the tumor initiation. Future efforts should focus on therapeutic interventions and further clinical, pathologic and molecular interrogation of this novel class of tumor suppressors.

Multidomain proapoptotic BAX and BAK, once activated, permeabilize mitochondria to trigger apoptosis, whereas antiapoptotic BCL-2 members preserve mitochondrial integrity. The BH3-only molecules (BH3s) promote apoptosis by either activating BAX-BAK or inactivating antiapoptotic members. Here, we present biochemical and genetic evidence that NOXA is a bona fide activator BH3. Using combinatorial gain-of-function and loss-of-function approaches in Bid−/−Bim−/−Puma−/−Noxa−/− and Bax−/−Bak−/− cells, we have constructed an interconnected hierarchical model that accommodates and explains how the intricate interplays between the BCL-2 members dictate cellular survival versus death. BID, BIM, PUMA and NOXA directly induce stepwise, bimodal activation of BAX-BAK. BCL-2, BCL-XL and MCL-1 inhibit both modes of BAX-BAK activation by sequestering activator BH3s and “BH3-exposed” monomers of BAX-BAK, respectively. Furthermore, autoactivation of BAX and BAK can occur independently of activator BH3s through downregulation of BCL-2, BCL-XL and MCL-1. Our studies lay a foundation on targeting the BCL-2 family for treating diseases with dysregulated apoptosis.