Melanoma is one of the most aggressive and treatment-resistant tumors that responsible for majority of skin-cancer related deaths. Here we propose a combination of MEK inhibitor binimetinib with metformin as a promising therapy against human melanoma cells in vitro, including BRAF -mutated A375, Mel Z, and Mel IL cells, and NRAS-mutated Mel MTP and Mel Me cells. Additionally, we obtained two close to clinical practice models of melanoma progression. The first one was vemurafenib-resistant Mel IL/R melanoma cells with acquired resistance to BRAF inhibition-targeted therapy, and the second one was tumor spheroids, which are 3D in vitro model of small-size solid tumors in vivo. The cytotoxicity of binimetinib and metformin was synergistic in both 2D and 3D melanoma culture and mediated through apoptotic pathway. The combination reduced the number of melanoma-formed colonies, inhibited cell invasion and migration, and led to G0/G1 cell cycle arrest through cyclin D/CDK4/CDK6 pathway. The mechanism of metformin and binimetinib synergy in melanoma cells was associated with increased activation of p-AMPKα and decreased p-ERK, but not with alterations in p-mTOR. In summary, the combination of metformin and binimetinib resulted in stronger anti-proliferative effects on melanoma cells compared to binimetinib alone, and therefore could be promising for clinical applications.

Oncolytic viruses, including live attenuated measles virus (MV) vaccine strains, have recently been shown as promising therapeutic agents against human malignancies. In this study, the oncolytic potential of the attenuated vaccine strain Leningrad-16 (L-16) of MV was evaluated in a panel of human metastatic melanoma cell lines. The L-16 measles virus was shown to replicate within melanoma cells mediating direct cell killing of tumor cells, although all melanoma cell lines varied in regard to their ability to respond to L-16 MV infection, as revealed by the different pattern of the Interferon Stimulated Gene expression, cytokine release and mechanisms of cell death. Furthermore, the statistically significant L-16 measles virus related tumor growth inhibition was demonstrated in a melanoma xenograft model. Therefore, L-16 MV represents an appealing oncolytic platform for target delivery of therapeutic genes along with other attenuated measles virus strains.

The incidence of malignant melanoma is increasing. The discovery of agents specifically targeting the mutated cascades has provided a good response for patients with oncogenic B-Raf proto-оncogene, serine/threonine kinase (BRAF). However, numerous studies continue to focus on novel methods of treatment to overcome acquired resistance to novel drugs. Recently, it has been revealed that inhibition of endoplasmic reticulum (ER) stress chaperon 78 kDa glucose-regulated protein 78 (GRP78) leads to down­regulation of autophagy and increased sensitivity to temozolomide (TMZ) treatment. Melanoma cells have a different sensitivity to TMZ treatment, which corresponds to the basal autophagy level. In the present study, we demonstrated that downregulation of GRP78 mitigated chemoresistance to TMZ in three melanoma cell lines. We found that downregulation of GRP78 led to inhibition of autophagy, cell cycle arrest in the G0/G1 phase, and activation of caspase-7-induced apoptosis, and this was affected by the initial autophagy level. Moreover, inhibition of GRP78 mitigated the combined TMZ and chloroquine effect. Our data revealed that autophagy inhibition through downregulation of ER stress response could overcome resistance to TMZ treatment in melanoma cells with a high basal level of autophagy treatment, which makes this combination a potential potent antitumor treatment for metastatic melanoma.

The phenomenon of the primary or acquired resistance of cancer cells to antitumor drugs is among the key problems of oncology. For breast cancer, the phenomenon of the resistance to hormonal or target therapy may be based on the numerous mechanisms including the loss or mutation of estrogen receptor, alterations of antiapoptotic pathways, overexpression of growth-related signaling proteins, etc. The perspective approaches for overcoming the resistance may be based on the usage of compounds such as inhibitors of the cell energetic metabolism. Among the latter, the antidiabetic drug metformin exerts antitumor activity via the activation of AMPK and the subsequent inhibition of mTOR signaling. The experiments were performed on the ERα-positive MCF-7 breast cancer cells, the MCF-7 sublines resistant to tamoxifen (MCF-7/T) and rapamycin (MCF-7/Rap), and on triple-negative MDA-MB-231 breast cancer cells. We have demonstrated metformin’s ability to enhance the cytostatic activity of the tamoxifen and rapamycin on both parent MCF-7 cells and MCF-7-resistant derivates mediated via the suppression of mTOR signaling and growth-related transcriptional factors. The cooperative effect of metformin and tested drugs was realized in an estrogen-independent manner, and, in the case of tamoxifen, was associated with the activation of apoptotic cell death. Similarly, the stimulation of apoptosis under metformin/tamoxifen co-treatment was shown to occur in the MCF-7 cells after steroid depletion as well as in the ERα-negative MDA-MB-231 cells. We conclude that metformin co-treatment may be used for the increase and partial restoration of the cancer cell sensitivity to hormonal and target drugs. Moreover, the combination of metformin with tamoxifen induces the apoptotic death in the ERα-negative breast cancer cells opening the additional perspectives in the treatment of estrogen-independent breast tumors.

Three artificial proteins that bind the gadolinium ion (Gd³⁺) with tumour-specific ligands were de novo engineered and tested as candidate drugs for binary radiotherapy (BRT) and contrast agents for magnetic resonance imaging (MRI). Gd³⁺-binding modules were derived from calmodulin. They were joined with elastin-like polypeptide (ELP) repeats from human elastin to form the four-centre Gd³⁺-binding domain (4MBS-domain) that further was combined with F3 peptide (a ligand of nucleolin, a tumour marker) to form the F3-W4 block. The F3-W4 block was taken alone (E2-13W4 protein), as two repeats (E1-W8) and as three repeats (E1-W12). Each protein was supplemented with three copies of the RGD motif (a ligand of integrin αvβ3) and green fluorescent protein (GFP). In contrast to Magnevist (a Gd-containing contrast agent), the proteins exhibited three to four times higher accumulation in U87MG glioma and A375 melanoma cell lines than in normal fibroblasts. The proteins remained for >24 h in tumours induced by Ca755 adenocarcinoma in C57BL/6 mice. They exhibited stability towards blood proteases and only accumulated in the liver and kidney. The technological advantages of using the engineered proteins as a basis for developing efficient and non-toxic agents for early diagnosis of tumours by MRI as well as part of BRT were demonstrated.

Background: More than 500 thousand new cases of malignant neoplasms are registered annually in the Russian Federation, of which more than 50 thousand new cases are due to hereditary forms. Improving the diagnosis of these diseases will make it possible to detect tumors at the early stages and take timely preventive and therapeutic measures. Aims: Creation of a database and development of a software for the NGS data analysis for the prevention and early diagnosis of hereditary forms of oncological diseases. Methods: The present study used 636 DNA samples obtained from cancer patients with a high hereditary risk or a burdened family history. DNA was isolated from blood lymphocytes. DNA libraries were prepared with a KAPA Target Enrichment Panel (Roche). The panel included probes for targeted enrichment of the coding region of 44 genes. NGS was performed on the MiSeq platform (Illumina). Results: We identified 65 pathogenic/ probably pathogenic nucleotide sequence variants in 96 patients in the ATM, BLM, BRCA1, BRCA2, CHEK2, EPCAM, MEN1, MLH1, MSH2, MSH3, MSH6, MUTYH, PALB2, TP53 genes. We also identified 2858 nucleotide sequence variants of unknown clinical significance. Conclusions: We have created a local database that contains both genetic variants and clinical and anamnestic data. The database contains 4763 nucleotide sequence variants at the moment, among which 2522 are unique variants identified in a single patient.