This experimental study assessed the oncolytic potential of a combination of vaccine-strain measles virus (MeV) and mumps virus (MuV) against colorectal cancer (CRC). The work evaluated anti-tumor activity both in vitro, using the human colorectal adenocarcinoma cell line HT-29, and in vivo, using a nude mouse xenograft model. The primary objective was to compare the combined MeV+MuV formulation (MM; MeV:MuV = 1:1, v/v) with single-virus treatments for effects on cell viability, induction of apoptosis, tumor growth, survival, and immune cell changes in treated animals.
HT-29 cells were cultured in Dulbecco's Modified Eagle Medium (DMEM) and infected with either MeV, MuV, or the 1:1 combination (MM). Cell viability was measured using the MTT assay, a colorimetric method that estimates viable cell metabolic activity. Apoptosis and cell death were assessed by flow cytometry. Synergy between the two viruses was quantified using a combination index (CI) at multiple time points (48, 72, and 96 hours).
The combination (MM) produced synergistic cytotoxic effects on HT-29 cells, with reported CI values of 0.473 at 48 hours, 0.692 at 72 hours, and 0.633 at 96 hours. Compared with infection by either MeV or MuV alone, MM-treated cells showed significantly lower viability (reported p < 0.05) across assessed time points. Apoptosis measured by flow cytometry was markedly higher in the MM group than in single-virus groups, with a reported significance of p < 0.01. These in vitro findings indicate that the combined vaccine-strain viruses acted together to increase tumor cell killing beyond the effects of either virus alone in the HT-29 cell line.
An immunodeficient nude mouse xenograft model bearing HT-29 tumors was used to evaluate in vivo oncolytic efficacy. The study compared animals treated with the combined MM preparation against groups treated with either MeV or MuV alone. Endpoints reported in the abstract include tumor growth rate, survival duration, mortality, and proportions of innate immune cell populations in the spleen.
In the xenograft model the MM-treated group exhibited significantly slower tumor growth than single-virus groups, with tumor growth differences reported as highly significant (p ≤ 0.001). The MM group also had significantly prolonged survival compared with single-virus treatments (p < 0.05) and a reduction in mortality. In addition to tumor and survival outcomes, the MM-treated animals demonstrated increased proportions of innate immune cell populations in the spleen relative to animals receiving single-virus treatments. The abstract attributes these combined antitumor and immunologic findings to superior efficacy of the MM combination over single-virus virotherapy in the chosen models.
The authors conclude that the 1:1 combination of vaccine-strain MeV and MuV (MM) exhibited synergistic and superior oncolytic efficacy against HT-29 colorectal cancer cells compared with single-virus therapies in both in vitro assays and an in vivo xenograft model. The paper's abstract highlights reduced cell viability, increased apoptosis, slower tumor growth, improved survival, reduced mortality, and augmented innate immune cell proportions in spleens as primary outcomes supporting the conclusion.
The abstract indicates that all authors declared no conflicts of interest. Specific methodological details not provided in the abstract—such as exact viral doses, administration routes and schedules, full characterization of the vaccine strains used, detailed immune cell phenotyping methods, safety or toxicity data, and longer-term follow-up—are not reported in the supplied source text and therefore cannot be summarized here.
Reference information available in the source: Mol Biol Rep. 2026 Sep 5;53(1):1537. DOI 10.1007/s11033-026-12724-8. PMID 42700211.