Browsing by Author "Wang, Xiaohu"

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    CCL21 Induces Plasmacytoid Dendritic Cell Migration and Activation in a Mouse Model of Glioblastoma
    (MDPI, 2024-10-12) Zhao, Lei; Shireman, Jack; Probelsky, Samantha; Rigg, Bailey; Wang, Xiaohu; Huff, Wei X.; Kwon, Jae H.; Dey, Mahua; Neurological Surgery, School of Medicine
    Dendritic cells (DCs) are professional antigen-presenting cells that are traditionally divided into two distinct subsets: myeloid DCs (mDCs) and plasmacytoid DCs (pDCs). pDCs are known for their ability to secrete large amounts of cytokine type I interferons (IFN- α). In our previous work, we have demonstrated that pDC infiltration promotes glioblastoma (GBM) tumor immunosuppression through decreased IFN-α secretion via TLR-9 signaling and increased suppressive function of regulatory T cells (Tregs) via increased IL-10 secretion, resulting in poor overall outcomes in mouse models of GBM. Further dissecting the overall mechanism of pDC-mediated GBM immunosuppression, in this study, we identified CCL21 as highly upregulated by multiple GBM cell lines, which recruit pDCs to tumor sites via CCL21-CCR7 signaling. Furthermore, pDCs are activated by CCL21 in the GBM microenvironment through intracellular signaling of β-arrestin and CIITA. Finally, we found that CCL21-treated pDCs directly suppress CD8+ T cell proliferation without affecting regulatory T cells (Tregs) differentiation, which is considered the canonical pathway of immunotolerant regulation. Taken together, our results show that pDCs play a multifaced role in GBM immunosuppression, and CCL21 could be a novel therapeutic target in GBM to overcome pDC-mediated immunosuppression.
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    Genomic analysis of human brain metastases treated with stereotactic radiosurgery reveals unique signature based on treatment failure
    (Elsevier, 2024-03-27) Shireman, Jack M.; White, Quinn; Ni, Zijian; Mohanty, Chitrasen; Cai, Yujia; Zhao, Lei; Agrawal, Namita; Gonugunta, Nikita; Wang, Xiaohu; Mccarthy, Liam; Kasulabada, Varshitha; Pattnaik, Akshita; Ahmed, Atique U.; Miller, James; Kulwin, Charles; Cohen-Gadol, Aaron; Payner, Troy; Lin, Chih-Ta; Savage, Jesse J.; Lane, Brandon; Shiue, Kevin; Kamer, Aaron; Shah, Mitesh; Iyer, Gopal; Watson, Gordon; Kendziorski, Christina; Dey, Mahua; Radiation Oncology, School of Medicine
    Stereotactic radiosurgery (SRS) has been shown to be efficacious for the treatment of limited brain metastasis (BM); however, the effects of SRS on human brain metastases have yet to be studied. We performed genomic analysis on resected brain metastases from patients whose resected lesion was previously treated with SRS. Our analyses demonstrated for the first time that patients possess a distinct genomic signature based on type of treatment failure including local failure, leptomeningeal spread, and radio-necrosis. Examination of the center and peripheral edge of the tumors treated with SRS indicated differential DNA damage distribution and an enrichment for tumor suppressor mutations and DNA damage repair pathways along the peripheral edge. Furthermore, the two clinical modalities used to deliver SRS, LINAC and GK, demonstrated differential effects on the tumor landscape even between controlled primary sites. Our study provides, in human, biological evidence of differential effects of SRS across BM's.
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    Genomic Analysis of Human Brain Metastases Treated with Stereotactic Radiosurgery Under the Phase-II Clinical Trial (NCT03398694) Reveals DNA Damage Repair at the Peripheral Tumor Edge
    (medRxiv, 2023-04-24) Shireman, Jack M.; White, Quinn; Agrawal, Namita; Ni, Zijian; Chen, Grace; Zhao, Lei; Gonugunta, Nikita; Wang, Xiaohu; Mccarthy, Liam; Kasulabada, Varshitha; Pattnaik, Akshita; Ahmed, Atique U.; Miller, James; Kulwin, Charles; Cohen-Gadol, Aaron; Payner, Troy; Lin, Chih-Ta; Savage, Jesse J.; Lane, Brandon; Shiue, Kevin; Kamer, Aaron; Shah, Mitesh; Iyer, Gopal; Watson, Gordon; Kendziorski, Christina; Dey, Mahua; Radiation Oncology, School of Medicine
    Stereotactic Radiosurgery (SRS) is one of the leading treatment modalities for oligo brain metastasis (BM), however no comprehensive genomic data assessing the effect of radiation on BM in humans exist. Leveraging a unique opportunity, as part of the clinical trial (NCT03398694), we collected post-SRS, delivered via Gamma-knife or LINAC, tumor samples from core and peripheral-edges of the resected tumor to characterize the genomic effects of overall SRS as well as the SRS delivery modality. Using these rare patient samples, we show that SRS results in significant genomic changes at DNA and RNA levels throughout the tumor. Mutations and expression profiles of peripheral tumor samples indicated interaction with surrounding brain tissue as well as elevated DNA damage repair. Central samples show GSEA enrichment for cellular apoptosis while peripheral samples carried an increase in tumor suppressor mutations. There are significant differences in the transcriptomic profile at the periphery between Gamma-knife vs LINAC.