RESUMEN
Understanding mechanisms of late/acquired cancer immunotherapy resistance is critical to improve outcomes; cellular immunotherapy trials offer a means to probe complex tumor-immune interfaces through defined T cell/antigen interactions. We treated two patients with metastatic Merkel cell carcinoma with autologous Merkel cell polyomavirus specific CD8+ T cells and immune-checkpoint inhibitors. In both cases, dramatic remissions were associated with dense infiltration of activated CD8+s into the regressing tumors. However, late relapses developed at 22 and 18 months, respectively. Here we report single cell RNA sequencing identified dynamic transcriptional suppression of the specific HLA genes presenting the targeted viral epitope in the resistant tumor as a consequence of intense CD8-mediated immunologic pressure; this is distinguished from genetic HLA-loss by its reversibility with drugs. Transcriptional suppression of Class I loci may underlie resistance to other immunotherapies, including checkpoint inhibitors, and have implications for the design of improved immunotherapy treatments.
Asunto(s)
Carcinoma de Células de Merkel/terapia , Genes MHC Clase I/genética , Inmunoterapia Adoptiva/métodos , Recurrencia Local de Neoplasia/genética , Infecciones por Polyomavirus/terapia , Neoplasias Cutáneas/terapia , Escape del Tumor/genética , Infecciones Tumorales por Virus/terapia , Antineoplásicos Inmunológicos/uso terapéutico , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/trasplante , Carcinoma de Células de Merkel/genética , Carcinoma de Células de Merkel/inmunología , Carcinoma de Células de Merkel/virología , Receptores Coestimuladores e Inhibidores de Linfocitos T/antagonistas & inhibidores , Regulación Neoplásica de la Expresión Génica , Genes MHC Clase I/inmunología , Humanos , Linfocitos Infiltrantes de Tumor/inmunología , Linfocitos Infiltrantes de Tumor/trasplante , Masculino , Poliomavirus de Células de Merkel/inmunología , Poliomavirus de Células de Merkel/aislamiento & purificación , Persona de Mediana Edad , Recurrencia Local de Neoplasia/inmunología , Infecciones por Polyomavirus/genética , Infecciones por Polyomavirus/inmunología , Infecciones por Polyomavirus/virología , Análisis de Secuencia de ARN/métodos , Análisis de la Célula Individual/métodos , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/inmunología , Neoplasias Cutáneas/virología , Neoplasias Testiculares/inmunología , Neoplasias Testiculares/secundario , Neoplasias Testiculares/virología , Transcripción Genética/inmunología , Trasplante Autólogo/métodos , Infecciones Tumorales por Virus/genética , Infecciones Tumorales por Virus/inmunología , Infecciones Tumorales por Virus/virologíaRESUMEN
Malignant melanoma is a highly aggressive and drug-resistant cancer. Virotherapy is a novel therapeutic strategy based on cancer cell lysis through selective virus replication. However, its clinical efficacy is modest, apparently related to poor virus replication within the tumors. We report that the growth compromised herpes simplex virus type 2 (HSV-2) mutant, DeltaPK, has strong oncolytic activity for melanoma largely caused by a mechanism other than replication-induced cell lysis. The ratio of dead cells (determined by trypan blue or ethidium homodimer staining) to cells that stain with antibody to the major capsid protein VP5 (indicative of productive infection) was 1.8-4.1 for different melanoma cultures at 24-72 h post-infection. Cell death was due to activation of calpain as well as caspases-7 and -3 and it was abolished by the combination of calpain (PD150606) and pancaspase (benzyloxycarbonyl-Val-Ala-Asp-fluormethyl ketone, z-VAD-fmk) inhibitors. Upregulation of the autopahgy protein Beclin-1 and the pro-apoptotic protein H11/HspB8 accompanied DeltaPK-induced melanoma oncolysis. Intratumoral DeltaPK injection (10(6)-10(7) plaque-forming unit (pfu)) significantly reduced melanoma tumor burden associated with calpain and caspases-7 and -3 activation, Beclin-1 and H11/HspB8 upregulation and activation of caspase-1-related inflammation. Complete remission was seen for 87.5% of the LM melanoma xenografts at 5 months after treatment termination. The data indicate that DeltaPK is a promising virotherapy for melanoma that functions through virus-induced programmed cell death pathways.