Pouring petrol on the flames: Using oncolytic virotherapies to enhance tumour immunogenicity

Biomimetic piezoelectric nanomaterial-modified oral microrobots for targeted catalytic and immunotherapy of colorectal cancer

Lactic acid (LA) accumulation in the tumor microenvironment poses notable challenges to effective tumor immunotherapy. Here, an intelligent tumor treatment microrobot based on the unique physiological structure and metabolic characteristics of Veillonella atypica (VA) is proposed by loading Staphylococcus aureus cell membrane-coating BaTiO3 nanocubes (SAM@BTO) on the surface of VA cells (VA-SAM@BTO) via click chemical reaction. Following oral administration, VA-SAM@BTO accurately targeted orthotopic colorectal cancer through inflammatory targeting of SAM and hypoxic targeting of VA. Under in vitro ultrasonic stimulation, BTO catalyzed two reduction reactions (O2 → •O2- and CO2 → CO) and three oxidation reactions (H2O → •OH, GSH → GSSG, and LA → PA) simultaneously, effectively inducing immunogenic death of tumor cells. BTO catalyzed the oxidative coupling of VA cells metabolized LA, effectively disrupting the immunosuppressive microenvironment, improving dendritic cell maturation and macrophage M1 polarization, and increasing effector T cell proportions while decreasing regulatory T cell numbers, which facilitates synergetic catalysis and immunotherapy.

Myeloid-derived suppressor cells: Key immunosuppressive regulators and therapeutic targets in cancer

Myeloid-derived suppressor cell (MDSC) mainly exists in tumor microenvironment (TME) and interferes with normal immune response of the body. These immature differentiated cells cooperate with tumor cells for immune escape and proliferation. The subtypes of MDSC are different in different organisms, and STAT become a high priority for the signaling pathway mediating the regulation of MDSC. The surface of MDSC cell population contains a variety of signal molecular receptors, and its differentiation degree is toilless to be chemotaxis by different factors. The role of MDSC in silencing T cells and promoting regulatory T cells (Treg) is particularly significant. This review mainly contains the origin of MDSC, the characteristics of subgroups, the focus of the study on MDSC heat molecules and signaling pathways, the relationship between MDSC and carcinoma, prognosis and hope to propose an overview of current MDSCs- targeting therapies so as to provide new ideas for cancer treatment.

Case report: Immunovirotherapy as a novel add-on treatment in a patient with thoracic NUT carcinoma

NUT carcinoma (NC) is a rare and extremely aggressive form of cancer, usually presenting with intrathoracic or neck manifestations in adolescents and young adults. With no established standard therapy regimen and a median overall survival of only 6.5 months, there is a huge need for innovative treatment options. As NC is genetically driven by a single aberrant fusion oncoprotein, it is generally characterized by a low tumor mutational burden, thus making it immunologically cold and insusceptible to conventional immunotherapy. Recently, we have demonstrated that oncolytic viruses (OVs) are able to specifically infect and lyse NC cells, thereby turning an immunologically cold tumor microenvironment into a hot one. Here, we report an intensive multimodal treatment approach employing for the first time an OV (talimogene laherparepvec (T-VEC); IMLYGIC®) together with the immune checkpoint inhibitor pembrolizumab as an add-on to a basic NC therapy (cytostatic chemotherapy, radiation therapy, epigenetic therapy) in a patient suffering from a large thoracic NC tumor which exhibits an aberrant, unique BRD3:NUTM1 fusion. This case demonstrates for the first time the feasibility of this innovative add-on immunovirotherapy regimen with a profound, repetitive and durable replication of T-VEC that is instrumental in achieving tumor stabilization and improvement in the patient´s quality of life. Further, a previously unknown BRD3:NUTM1 fusion gene was discovered that lacks the extraterminal domain of BRD3.

Targeting the Retinoblastoma/E2F repressive complex by CDK4/6 inhibitors amplifies oncolytic potency of an oncolytic adenovirus

CDK4/6 inhibitors (CDK4/6i) and oncolytic viruses are promising therapeutic agents for the treatment of various cancers. As single agents, CDK4/6 inhibitors that are approved for the treatment of breast cancer in combination with endocrine therapy cause G1 cell cycle arrest, whereas adenoviruses induce progression into S-phase in infected cells as an integral part of the their life cycle. Both CDK4/6 inhibitors and adenovirus replication target the Retinoblastoma protein albeit for different purposes. Here we show that in combination CDK4/6 inhibitors potentiate the anti-tumor effect of the oncolytic adenovirus XVir-N-31 in bladder cancer and murine Ewing sarcoma xenograft models. This increase in oncolytic potency correlates with an increase in virus-producing cancer cells, enhanced viral genome replication, particle formation and consequently cancer cell killing. The molecular mechanism that regulates this response is fundamentally based on the reduction of Retinoblastoma protein expression levels by CDK4/6 inhibitors.

Neither CDK4/6 inhibitors nor oncolytic adenoviruses show high efficiency as monotherapy in the treatment of cancer. Authors show here that when combined, CDK4/6 inhibitors deplete Retinoblastoma protein levels, which leads to more efficient virus replication and an increase in oncolytic virus-producing cancer cells and thus to efficient anti-tumor response in mouse xenograft sarcoma models.

Carvedilol targets β-arrestins to rewire innate immunity and improve oncolytic adenoviral therapy

Oncolytic viruses are being tested in clinical trials, including in women with ovarian cancer. We use a drug-repurposing approach to identify existing drugs that enhance the activity of oncolytic adenoviruses. This reveals that carvedilol, a β-arrestin-biased β-blocker, synergises with both wild-type adenovirus and the E1A-CR2-deleted oncolytic adenovirus, dl922-947. Synergy is not due to β-adrenergic blockade but is dependent on β-arrestins and is reversed by β-arrestin CRISPR gene editing. Co-treatment with dl922-947 and carvedilol causes increased viral DNA replication, greater viral protein expression and higher titres of infectious viral particles. Carvedilol also enhances viral efficacy in orthotopic, intraperitoneal murine models, achieving more rapid tumour clearance than virus alone. Increased anti-cancer activity is associated with an intratumoural inflammatory cell infiltrate and systemic cytokine release. In summary, carvedilol augments the activity of oncolytic adenoviruses via β-arrestins to re-wire cytokine networks and innate immunity and could therefore improve oncolytic viruses for cancer patient treatment.