Oncolytic virotherapy is a rapidly evolving approach to cancer treatment. Our group previously designed VV-GMCSF-Lact, a recombinant oncolytic vaccinia virus targeting solid tumors including gliomas. In this study, we used single-cell RNA sequencing to compare transcriptional responses in human glioma cells, non-malignant brain cells, and immortalized glioblastoma U87 MG cells following infection with this oncolytic virus. We found that proneural glioblastoma cells and microglia-like cells from patient-derived glioma cultures were the most susceptible to VV-GMCSF-Lact. Increased expressions of histones, translational regulators, and ribosomal proteins positively correlated with viral load at the transcript level. Furthermore, higher viral loads were accompanied by a large-scale downregulation of genes involved in mitochondrial translation, metabolism, and oxidative phosphorylation. Levels of early vaccinia virus transcripts are also positively correlated with infection intensity, suggesting that the fate of cells is determined at the early stage of infection.

Background/Objectives: Oncolytic viruses are an immunotherapeutic approach that can modulate the tumor microenvironment (TME), transforming immunologically ‘cold’ tumors into ‘hot’ ones. Insertion of genes encoding immunomodulatory proteins can further enhance antitumor immune responses. In this study, we compared the antitumor and immunomodulatory effects of the double recombinant vaccinia virus VV-GMCSF-Lact, which carries the human GM-CSF gene, with those of recombinant human GM-CSF (rhGM-CSF) in an immunocompetent murine GL261 glioma model. Methods: The study was conducted using a subcutaneous GL261 glioma model in immunocompetent C57BL/6 mice, comparing intratumoral VV-GMCSF-Lact and rhGM-CSF treatments with evaluation of immune cell populations by flow cytometry, tumor morphology by H&E staining, and tumor transcriptome profiles by RNA sequencing. Results: Flow cytometry showed that VV-GMCSF-Lact reduced the number of immunosuppressive cells in the TME of subcutaneously transplanted gliomas, targeting different components of the TME depending on animal sex. The immunotherapeutic effects of rhGM-CSF were less pronounced and primarily affected peripheral immune cells. Histological analysis revealed a decrease in mitotic figures in tumors from female mice after viral therapy. Transcriptome profiling of GL261 tumors demonstrated divergent gene expression patterns and cellular compositions between treatment groups. VV-GMCSF-Lact treatment was associated with a decreased proportion of malignant GL261 cells and CD8⁺ T lymphocytes, while rhGM-CSF treatment increased proportions of MDSCs, macrophages, NK cells, and tumor-associated neutrophils. Conclusions: Taken together, our data demonstrate that VV-GMCSF-Lact induces antitumor immune responses in murine GL261 glioma in vivo and modulates the tumor microenvironment more effectively than rhGM-CSF alone, supporting its potential for developing new strategies for glioma treatment.

Cervical cancer remains a significant global health burden, with chemoradioresistance representing a major obstacle to successful treatment. To elucidate the mechanisms underlying this resistance, we established a unique pair of isogenic primary cervical cancer cell lines, AdMer35 and AdMer43, obtained from a patient with squamous cell carcinoma of the cervix before and after radiation therapy. The aim of our study was to characterize the transcriptomic and cellular heterogeneity of these cells. We conducted an in-depth comparative analysis using single-cell RNA sequencing. Analysis of this paired, patient-derived isogenic model suggests that chemoradioresistance can arise through coordinated multilevel cellular adaptations. Resistant AdMer43 cells demonstrated transcriptional reprogramming, with the upregulation of embryonic stemness factors (HOX, POU5F1, SOX2), a shift in extracellular matrix from fibrillar to non-fibrillar collagens, and activation of inflammatory pathways. We identified and characterized critical cell-state dynamics: resistant cells exhibited a remodeled ecosystem with a metabolically reprogrammed senescent-like cell population showing an enhanced pro-tumorigenic communication via EREG, SEMA3C, BMP, and WNT pathways. Furthermore, we identified a progenitor-like cell population with a minimal CNV burden, potentially serving as a reservoir for tumor persistence. These findings offer novel insights for developing targeted strategies to eliminate resistant cell pools and improve cervical cancer outcomes.

Both oncolytic virotherapy and immune checkpoint blockade are being actively explored as immunotherapy treatments for glioblastoma, one of the most lethal malignancies. Nevertheless, the antitumor molecular mechanisms of these therapies remain poorly understood, particularly whether they induce overlapping or distinct transcriptional programs. No comprehensive transcriptome-wide characterization and direct comparison of the responses induced by VV-GMCSF-Lact and anti-PD-1 therapy in glioma have been reported. To address this question, we performed whole-transcriptome profiling of GL261 tumors from immunocompetent C57BL/6 mice treated with VV-GMCSF-Lact, anti-PD-1 antibodies, or their combination. We analyzed therapy-associated changes in gene expression, signaling pathways, and tumor composition. Our findings indicate that anti-PD-1 and combination treatment led to distinctive activation of interferon-gamma response, JAK/STAT signaling, and TNF-alpha/NF-kB pathways. In contrast, VV-GMCSF-Lact preferentially activated T, B, and natural killer T cell-associated programs and reduced the relative abundance of malignant cells. Notably, combination therapy was associated with unique molecular patterns, including induction of monocyte and granulocyte chemotaxis-associated genes, downregulation of PP2A-regulated signaling, and suppression of Rap1-related pathways. This suggests that VV-GMCSF-Lact and anti-PD-1 therapy induce transcriptionally distinct, yet complementary, immune reprogramming and support further evaluation of their combination for glioma immunotherapy.