Background/Aim: Oncolytic adenoviruses are promising therapeutic agents against both the bulk of tumor cells and cancer stem cells. The present study intended to test the oncolytic capability of adenovirus serotype 6 (Ad6), which has a lower seroprevalence and hepatotoxicity relatively to adenovirus 5 (Ad5), against the glioblastoma and its cancer stem cells. Materials and Methods: Oncolytic efficacy of Ad6 was compared to widespread Ad5 both in vitro and in vivo, using the U87 and U251 human glioblastoma cell lines and subcutaneously transplanted U87 cells in SCID mice, respectively. Results: Ad6 had a dose-dependent cytotoxicity toward glioblastoma cells in vitro and its intratumoral injections lead to a significant (p<0.05) decrease in volume of U87 xenografts, similarly to Ad5. Based on the innate capability of glioblastoma cancer stem cells to internalize a fluorescent-labeled double-stranded DNA probe, the spatial localization of these cells was estimated and it was shown that the number of cancer stem cells tended to decrease under adenovirus therapy as compared to the control group. Conclusion: Ad6 was shown to be a promising agent for treating glioblastomas.

Expression levels of five miRNAs (miR-19b, miR-21, miR-126, miR-141, miR-205) were measured in the plasma of healthy donors and prostate cancer patients. It was shown that miR-141 expression level efficiently discriminates early stage prostate cancer patients and correlates with the Gleason score.

Adenovirus vectors are the most frequently used agents for gene therapy, including oncolytic therapy and vaccine development. It’s hard to overestimate the value of adenoviruses during the COVID-19 pandemic as to date four out of four approved viral vector-based SARS-CoV-2 vaccines are developed on adenovirus platform. The vast majority of adenoviral vectors are based on the most studied human adenovirus type 5 (HAdV-C5), however, its immunogenicity often hampers the clinical translation of HAdV-C5 vectors. The search of less seroprevalent adenovirus types led to another species C adenovirus, Adenovirus type 6 (HAdV-C6). HAdV-C6 possesses high oncolytic efficacy against multiple cancer types and remarkable ability to induce the immune response towards carrying antigens. Being genetically very close to HAdV-C5, HAdV-C6 differs from HAdV-C5 in structure of the most abundant capsid protein, hexon. This leads to the ability of HAdV-C6 to evade the uptake by Kupffer cells as well as to distinct opsonization by immunoglobulins and other blood proteins, influencing the overall biodistribution of HAdV-C6 after systemic administration. This review describes the structural features of HAdV-C6, its interaction with liver cells and blood factors, summarizes the previous experiences using HAdV-C6, and provides the rationale behind the use of HAdV-C6 for vaccine and anticancer drugs developments.

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Urine of prostate cancer patients contains tumor-specific biopolymers, including protein- and microvesiclesassociated miRNAs that can potentially be used as oncomarkers. Previously we have characterized urine extracellular vesicles and demonstrated diagnostic potential of their miRNA cargo. In this study, we have performed a comparative analysis of the expression of 84 miRNA in paired samples of urine microvesicles and clarified urine from healthy men, patients with benign hyperplasia and cancer of the prostate using miRCURY LNA miRNA qPCR Panels. Subsets of miRNAs with differences in expression between the fractions of the urine were found in all three groups. Two groups of miRNA were identified based on the patterns of their differential expression. They regulate several key signaling pathways associated with prostate cancer development.