Advances in the design and development of oncolytic measles viruses

Recombinant Chinese Hu191 measles virus exhibits a significant antitumor activity against nephroblastoma mediated by immunogenic form of apoptosis

In previous studies oncolytic measles viruses (MVs) have shown significant antitumor activity against various tumors. In our research recombinant MV-Hu191 (rMV-Hu191), established via reverse genetics technology and expressing enhanced green fluorescent protein (EGFP), was evaluated for its therapeutic effects and related mechanisms against nephroblastoma cell lines. We built three different constructs based on rMV-Hu191 to express EGFP effectively. Our experiments showed that rMV-Hu191 expressing EGFP could efficiently infect and replicate in nephroblastoma cell lines. Caspase-induced apoptosis exerted a significant impact on MV-induced cell death, which was accompanied by emission of cellular ATP and high-mobility group protein 1 (HMGB1) and by translocation of calreticulin (CRT). Intratumoral injection of rMV-Hu191-EGFP resulted in significant regression of tumors in a G401 xenograft model. Our results indicate that the MV-Hu191 strain, which is widely used in China, is an appropriate vector for expression of foreign genes and could serve as a potentially good candidate for nephroblastoma therapy mediated by induction of apoptosis-associated immunogenic cell death (ICD).

Oncolytic Virotherapy in Glioma Tumors

Glioma tumors are one of the most devastating cancer types. Glioblastoma is the most advanced stage with the worst prognosis. Current therapies are still unable to provide an effective cure. Recent advances in oncolytic immunotherapy have generated great expectations in the cancer therapy field. The use of oncolytic viruses (OVs) in cancer treatment is one such immune-related therapeutic alternative. OVs have a double oncolytic action by both directly destroying the cancer cells and stimulating a tumor specific immune response to return the ability of tumors to escape the control of the immune system. OVs are one promising alternative to conventional therapies in glioma tumor treatment. Several clinical trials have proven the feasibility of using some viruses to specifically infect tumors, eluding undesired toxic effects in the patient. Here, we revisited the literature to describe the main OVs proposed up to the present moment as therapeutic alternatives in order to destroy glioma cells in vitro and trigger tumor destruction in vivo. Oncolytic viruses were divided with respect to the genome in DNA and RNA viruses. Here, we highlight the results obtained in various clinical trials, which are exploring the use of these agents as an alternative where other approaches provide limited hope.

Designing and building oncolytic viruses

Oncolytic viruses (OVs) are engineered and/or evolved to propagate selectively in cancerous tissues. They have a dual mechanism of action; direct killing of infected cancer cells cross-primes anticancer immunity to boost the killing of uninfected cancer cells. The goal of the field is to develop OVs that are easily manufactured, efficiently delivered to disseminated sites of cancer growth, undergo rapid intratumoral spread, selectively kill tumor cells, cause no collateral damage and pose no risk of transmission in the population. Here we discuss the many virus engineering strategies that are being pursued to optimize delivery, intratumoral spread and safety of OVs derived from different virus families. With continued progress, OVs have the potential to transform the paradigm of cancer care.