Accessibility within chromatin is an important factor in the prompt removal of UV-induced DNA damage by nucleotide excision repair (NER). Chromatin remodeling by the SWI/SNF complex has been shown to play an important modulating role in NER in vitro and yeast in vivo. Nevertheless, the molecular basis of cross-talk between SWI/SNF and NER in mammalian cells is not fully understood. Here, we show that knockdown of Brg1, the ATPase subunit of SWI/SNF, negatively affects the elimination of cyclobutane pyrimidine dimers (CPD), but not of pyrimidine (6, 4)pyrimidone photoproducts (6-4PP) following UV irradiation of mammalian cells. Brg1-deficient cells exhibit a lower chromatin relaxation as well as impaired recruitment of downstream NER factors, XPG and PCNA, to UV lesions. However, the assembly of upstream NER factors, DDB2 and XPC, at the damage site was unaffected by Brg1 knockdown. Interestingly, Brg1 interacts with XPC within chromatin and is recruited to UV-damaged sites in a DDB2-and XPC-dependent manner. Also, postirradiation decrease of XPC levels occurred more rapidly in Brg1-deficient than normal cells. Conversely, XPC transcription remained unaltered upon Brg1 knockdown indicating that Brg1 affects the stability of XPC protein following irradiation. Thus, Brg1 facilitates different stages of NER by initially modulating UV-induced chromatin relaxation and stabilizing XPC at the damage sites, and subsequently stimulating the recruitment of XPG and PCNA to successfully culminate the repair.

A Wani (2014) USP3 counteracts RNF168 via deubiquitinating H2A and γH2AX at lysine 13 and 15, Cell Cycle, 13:1, 106-114,

Purpose Our goal is to test if CS1 could be targeted by CAR T cells to treat MM. Experimental Design We generated a retroviral construct of a CS1-specific CAR and engineered primary human T cells expressing the CAR. We then tested the capacity of CS1-CAR T cells to eradicate human multiple myeloma tumor cells in vitro, ex vivo and in vivo using orthotopic MM xenograft mouse models. Results In vitro, compared to mock-transduced T cells, upon recognizing CS1 positive MM cells, CS1-CAR-tranduced T cells secreted more IFN-γ as well as IL-2, expressed higher levels of the activation marker CD69, showed higher capacity for degranulation, and displayed enhanced cytotoxicity. Ectopically forced expression of CS1 in MM cells with low CS1 expression enhanced recognition and killing by CAR T cells. Ex vivo, CS1-CAR T cells also showed similarly enhanced activities when responding to primary MM cells. More importantly, in orthotopic MM xenograft mouse models, adoptive transfer of human primary T cells expressing CS1-CAR efficiently suppressed the growth of human MM.1S and IM9 myeloma cells and significantly prolonged mouse survival. Conclusions CS1 is a promising antigen that can be targeted by CAR-expressing T cells for treatment of MM.

Oncolytic viruses including oncolytic herpes simplex virus (oHSV) have produced provocative therapeutic responses in patients with glioblastoma (GB), the most aggressive brain tumor. Paradoxically, innate immune responses mediated by natural killer (NK) cells and macrophages/microglia appear to limit oHSV efficacy. Therefore, we investigated whether pretreatment with an immunosuppressive cytokine, TGF-β, might reverse these effects and thereby potentiate oHSV efficacy. TGF-β treatment of NK cells rendered them less cytolytic against oHSV-infected GB cells and stem-like cells in vitro. Further, TGF-β treatment of NK cells, macrophages or microglia increased viral titers of oHSV in co-cultures with GB cells. In a syngeneic mouse model of GB, administering TGF-β prior to oHSV injection inhibited intracranial infiltration and activation of NK cells and macrophages. Notably, a single administration of TGF-β prior to oHSV therapy was sufficient to phenocopy NK cell depletion and suppress tumor growth and prolong survival in both orthograft and syngeneic models of GB. Collectively, our findings show how administering a single dose of TGF-β prior to oncolytic virus treatment of GB can transiently inhibit innate immune cells that limit efficacy, thereby improving therapeutic responses and survival outcomes.

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