Abstract 1605: Oncolytic hsv-1(vc2) gm-csf regulates the proinflammatory profile suggestive of an immunomodulatory effect in PDAC cells
Authors: Ramulu Naveen Chintala , Thota Shilpa , Stanfield Brent , Kousoulas Konstantin , Francis Joseph 
Published: March 2024

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease that is projected to be the second leading cause of cancer-associated deaths by 2030. Owing to its intrinsic immune evasive tumor microenvironment (TME), PDAC is regarded as an immunologically “cold” tumor with a significant therapeutic challenge. Although 5-fluorouracil or gemcitabine-based chemotherapy is considered as standard of care, harnessing immunological pathways may potentially convert PDAC to a “hot” tumor, thereby providing survival advantage to patients. Lately, the use of oncolytic virus has proven to be an alternative strategy to activate the innate immune response within the TME coupled with its cytotoxic effect against the cancer cells. The FDA approval of T-VEC for the treatment of stage IIIB/IV melanoma validates the preceding argument. In this study, we have investigated the effect of herpes simplex virus type-1 (HSV-1) (VC2) overexpressing granulocyte-macrophage colony-stimulating factor (GMCSF), HSV-1VC2GM-CSF in the murine KRAS, p53, and Cre (KPC), and human MIA PaCa-2 pancreatic carcinoma cells. Following a 24h infection of the KPC and MIA PaCa-2 cells with the HSV-1VC2GM-CSF, the observed cytopathic effects (CPE) included cell rounding, detachment, and aggregation as compared to the wild-type HSV-1VC2 treated or the uninfected control cells. The CPE effect of HSV-1VC2GM-CSF was proven to be a more direct and dynamic response against these cells. In the next steps, the viral titers were determined to be 9.6E7 pfu/ml, 1.26E7 pfu/ml for HSV-1VC2 and VC2GM-CSF respectively. The infection of VC2GM-CSF 0.1, 1.0 and 10 MOI in KPC cells resulted in a significant increase in the expression of proinflammatory markers including interleukin 10 (IL-10), cyclooxygenase -2 (COX-2) and iNOS at the gene level in contrast to the uninfected controls. This was coupled with an increase in the expression of Fas ligand (FasL) in the treated cells. Intriguingly, the treated cells showed a significant upregulation of programmed death ligand (PD-L1). Interestingly, in a 3D-coculture of KPC and RAW264.7 cells the expression of PD-L1 was significantly upregulated. Based on the evidence presented here, it is speculated that VC2GM-CSF-induced proinflammatory profile in KPC and Mia PaCa-2 cells converts to an immunomodulatory one characterized by the regulation of FasL and PD-L1. The effect of VC2GM-CSF in a PDAC organoid model to understand the interplay between the tumor and the stromal cells in response to the virus is currently underway.

Citation Format: Naveen Chintala Ramulu, Shilpa Thota, Brent Stanfield, Konstantin Kousoulas, Joseph Francis. Oncolytic hsv-1(vc2) gm-csf regulates the proinflammatory profile suggestive of an immunomodulatory effect in PDAC cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1605.