ORCID Profile
0000-0002-7075-5463
Current Organisation
University of California, San Diego
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Publisher: Elsevier BV
Date: 09-2020
Publisher: MyJove Corporation
Date: 08-06-2018
DOI: 10.3791/57265
Publisher: American Association for Cancer Research (AACR)
Date: 05-2020
DOI: 10.1158/1535-7163.MCT-19-0959
Abstract: Gastrointestinal stromal tumor (GIST), the most common sarcoma, is characterized by KIT protein overexpression, and tumors are frequently driven by oncogenic KIT mutations. Targeted inhibition of KIT revolutionized GIST therapy and ushered in the era of precision medicine for the treatment of solid malignancies. Here, we present the first use of a KIT-specific DNA aptamer for targeted labeling of GIST. We found that an anti-KIT DNA aptamer bound cells in a KIT-dependent manner and was highly specific for GIST cell labeling in vitro. Functionally, the KIT aptamer bound extracellular KIT in a manner similar to KIT mAb staining, and was trafficked intracellularly in vitro. The KIT aptamer bound dissociated primary human GIST cells in a mutation agnostic manner such that tumors with KIT and PDGFRA mutations were labeled. In addition, the KIT aptamer specifically labeled intact human GIST tissue ex vivo, as well as peritoneal xenografts in mice with high sensitivity. These results represent the first use of an aptamer-based method for targeted detection of GIST in vitro and in vivo.
Publisher: American Association for Cancer Research (AACR)
Date: 10-2019
DOI: 10.1158/2326-6066.CIR-19-0101
Abstract: Irreversible electroporation (IRE) is a nonthermal ablation technique that is used clinically in selected patients with locally advanced pancreatic cancer, but most patients develop recurrent distant metastatic disease. We hypothesize that IRE can induce an in situ vaccination effect by releasing tumor neoantigens in an inflammatory context. Using an immunocompetent mouse model, we demonstrated that IRE alone produced complete regression of subcutaneous tumors in approximately 20% to 30% of mice. IRE was not effective in immunodeficient mice. Mice with complete response to IRE demonstrated prophylactic immunity and remained tumor free when rechallenged with secondary tumors on the contralateral flank. CD8+ T cells from IRE-responsive mice were reactive against peptides representing model-inherent alloantigens and conferred protection against tumor challenge when adoptively transferred into immunocompromised, tumor-naïve mice. Combining IRE with intratumoral Toll-like receptor-7 (TLR7) agonist (1V270) and systemic anti-programmed death-1 receptor (PD)-1 checkpoint blockade resulted in improved treatment responses. This combination also resulted in elimination of untreated concomitant distant tumors (abscopal effects), an effect not seen with IRE alone. These results suggest that the systemic antitumor immune response triggered by IRE can be enhanced by stimulating the innate immune system with a TLR7 agonist and the adaptive immune system with anti–PD-1 checkpoint blockade simultaneously. Combinatorial approaches such as this may help overcome the immunosuppressive pancreatic cancer microenvironment.
Publisher: Springer Science and Business Media LLC
Date: 06-04-2022
DOI: 10.1007/S12672-022-00483-4
Abstract: There is a great need to reduce the toxicity of chemotherapy used in the management of pancreatic ductal adenocarcinoma (PDAC). Here we explore if regional pressurized delivery of oxaliplatin can minimize peripheral neuropathy in mice. We used an orthotopic PDAC mouse model and delivered a single dose of oxaliplatin through the portal vein using a pressure-enabled system (pancreatic retrograde venous infusion, PRVI). We analyzed the effects of PRVI on tumor burden and peripheral neuropathy using histopathological and functional assays. Tumor weights in mice treated with 2 mg/kg oxaliplatin using PRVI were significantly lower than in mice treated with the same dose systemically. This resulted in reduced peripheral neuropathy signatures in PRVI mice compared to the 20 mg/kg systemic dose required to achieve similar tumor control. Regional delivery of highly cytotoxic agents using PRVI can reduce the therapeutic dose of these drugs, thereby lowering toxic side effects.
Publisher: BMJ
Date: 2023
Abstract: Pancreatic cancer (PC) has a poor prognosis, and most patients present with either locally advanced or distant metastatic disease. Irreversible electroporation (IRE) is a non-thermal method of ablation used clinically in locally advanced PC, but most patients eventually develop distant recurrence. We have previously shown that IRE alone is capable of generating protective, neoantigen-specific immunity. Here, we aim to generate meaningful therapeutic immune effects by combining IRE with local (intratumoral) delivery of a CD40 agonistic antibody (CD40Ab). KPC46 organoids were generated from a tumor-bearing male KrasLSL-G12D-p53LSL-R172H-Pdx-1-Cre (KPC) mouse. Orthotopic tumors were established in the pancreatic tail of B6/129 F1J mice via laparotomy. Mice were randomized to treatment with either sham laparotomy, IRE alone, CD40Ab alone, or IRE followed immediately by CD40Ab injection. Metastatic disease and immune infiltration in the liver were analyzed 14 days postprocedure using flow cytometry and multiplex immunofluorescence imaging with spatial analysis. Candidate neoantigens were identified by mutanome profiling of tumor tissue for ex vivo functional analyses. The combination of IRE+CD40 Ab improved median survival to greater than 35 days, significantly longer than IRE (21 days) or CD40Ab (24 days) alone (p .01). CD40Ab decreased metastatic disease burden, with less disease in the combination group than in the sham group or IRE alone. Immunohistochemistry of liver metastases revealed a more than twofold higher infiltration of CD8+T cells in the IRE+CD40 Ab group than in any other group (p .01). Multiplex immunofluorescence imaging revealed a 4–6 fold increase in the density of CD80+CD11c+ activated dendritic cells (p .05), which were spatially distributed throughout the tumor unlike the sham group, where they were restricted to the periphery. In contrast, CD4+FoxP3+ T-regulatory cells (p .05) and Ly6G+myeloid derived cells (p .01) were reduced and restricted to the tumor periphery in the IRE+CD40 Ab group. T-cells from the IRE+CD40 Ab group recognized significantly more peptides representing candidate neoantigens than did T-cells from the IRE or untreated control groups. IRE can induce local tumor regression and neoantigen-specific immune responses. Addition of CD40Ab to IRE improved dendritic cell activation and neoantigen recognition, while generating a strong systemic antitumor T-cell response that inhibited metastatic disease progression.
Location: United States of America
Location: United States of America
No related grants have been discovered for Partha Ray.