Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal malignancy that has the worst 5-year survival rate of all of the common malignant tumors. Surgery, chemotherapy, and/or chemoradiation remain the main tactics for PDAC treatment. The efficacy of chemotherapy is often compromised because of the substantial risk of severe toxicities. In our study, we focused on identification of polymorphisms in the genes involved in drug metabolism, DNA repair and replication that are associated with inter-individual differences in drug-induced toxicities. Using the microarray, we genotyped 12 polymorphisms in the DPYD, XPC, GSTP1, MTHFR, ERCC1, UGT1A1, and TYMS genes in 78 PDAC patients treated with FOLFIRINOX. It was found that the TYMS rs11280056 polymorphism (6 bp-deletion in TYMS 3′-UTR) predicted grade 1–2 neurotoxicity (p = 0.0072 and p = 0.0019, according to co-dominant (CDM) and recessive model (RM), respectively). It is the first report on the association between TYMS rs11280056 and peripheral neuropathy. We also found that PDAC patients carrying the GSTP1 rs1695 GG genotype had a decreased risk for grade 3–4 hematological toxicity as compared to those with the AA or AG genotypes (p = 0.032 and p = 0.014, CDM and RM, respectively). Due to relatively high p-values, we consider that the impact of GSTP1 rs1695 requires further investigation in a larger sample size.

Background: Undifferentiated pleomorphic sarcoma (UPS) is a highly malignant mesenchymal tumor that ranks as one of the most common types of soft tissue sarcoma. Even though chemotherapy increases the 5-year survival rate in UPS, high tumor heterogeneity frequently leads to chemotherapy resistance and consequently to recurrences. In this study, we characterized the cell composition and the transcriptional profile of UPS with resistance to chemotherapy at the single cell resolution. Methods: A 58-year-old woman was diagnosed with a 13.6 × 9.3 × 6.0 cm multi-nodular tumor with heterogeneous cysto-solid structure at the level of the distal metadiaphysis of the left thigh during magnetic resonance tomography. Morphological and immunohistochemical analysis led to the diagnosis of high-grade (G3) UPS. Neoadjuvant chemotherapy, surgery (negative resection margins), and adjuvant chemotherapy were conducted, but tumor recurrence developed. The UPS sample was used to perform single-cell RNA sequencing by chromium-fixed RNA profiling. Results: Four subpopulations of tumor cells and seven subpopulations of tumor microenvironment (TME) have been identified in UPS. The expression of chemoresistance genes has been detected, including KLF4 (doxorubicin and ifosfamide), ULK1, LUM, GPNMB, and CAVIN1 (doxorubicin), and AHNAK2 (gemcitabine) in tumor cells and ETS1 (gemcitabine) in TME. Conclusions: This study provides the first description of the single-cell transcriptome of UPS with resistance to two lines of chemotherapy, showcasing the gene expression in subpopulations of tumor cells and TME, which may be potential markers for personalized cancer therapy.

The search for markers applicable for efficient differential diagnosis and personalized therapy is a priority task of experimental neuro-oncology. Modern molecular methods allow us to analyze human biopsy material; however, further actions with this extracted tumor tissue are limited. Relevant and sophisticated CNS tumor models are required for precise therapy development. Although it is possible to use human biomaterial to create 2D and 3D cultures and implant them into xenograft animals, the data generated from such models is limited. Due to changes in the classification of the CNS tumors in 2021, a representative model should have not only morphological similarity to human tumors but also key genetic aberrations for studying the mechanisms of carcinogenesis and personalized therapy (such as PDGFRa, Olig1/2, Sox2, and Mki67) for different glioma models such as astrocytoma, oligodendroglioma, and glioblastoma. On the basis of a unique scientific facility “The Collection of experimental tumors of the nervous system and neural tumor cell lines” (Avtsyn Research Institute of Human Morphology of “Petrovsky National Research Center of Surgery”), there is a biobank of chemically induced transplantable tumors of laboratory animals. Their properties, mechanisms, and progression closely correlate with malignant CNS neoplasms in humans. These are potentially useful for identifying novel signaling pathways associated with oncogenesis in the nervous system and personalizing therapeutic approaches. In our work, we characterized a tissue-transplantable brain tumor strain of rat glioma101.8 using MRI, IHC, scRNA-seq, and qPCR-RT methods. According to this study, the cellular composition of the tissue-transplantable rat glioma 101.8 strain was determined, as well as the major genetic signature characteristics of each cell population of this tissue-transplantable strain and its microenvironment.

Pleomorphic rhabdomyosarcoma is a rare soft-tissue tumor that occupies an uncertain middle ground between rhabdomyosarcoma and undifferentiated pleomorphic sarcoma. With its relative rarity, aggressiveness, and lack of detailed characterization, it presents a challenging task for therapeutic treatment. In this case study, we use single-cell transcriptomics to investigate the heterogeneous landscape of pRMS and the tumor microenvironment. We demonstrate that the tumor populations in pRMS have a clear division into myogenic and non-myogenic clusters, with the non-myogenic clusters having more numerous communication links with the immune populations. All pRMS tumor clusters use the MIF-CD74 pathway to suppress the immune response, while APP, PTN, and CXCL12 signaling are employed predominantly by the non-myogenic tumor clusters. The cytotoxic T cells in pRMS bear markers of exhaustion (LAG3, HAVCR2, EOMES), and the macrophages express myeloid checkpoint-related genes (SIGLEC1, SIRPA, CSF1R, HAVCR2). This transcriptomic data suggests that targeting MIF and APP signaling in pRMS may have therapeutic potential; however, studies on multiple-patient cohorts, protein verification, and in vitro and in vivo validation are still needed for clinical actionability.

The site-directed mutagenesis of the monomeric red fluorescent protein TagRFP and its variants was performed with the goal of generating reversibly photoactivatable fluorescent proteins. Amino acids...

Objective: Myxofibrosarcoma (MXF) and undifferentiated pleomorphic sarcoma (UPS) are common and aggressive subtypes of cancer differing by clinical characteristics and prognosis; however, their differential diagnosis is difficult. Elucidation of cellular and transcriptomic discrepancies between these diseases that could improve their identification was the aim of our study. Methods: We applied single-cell RNA sequencing to compare MXF and UPS by tumor cell clusters and cell–cell ligand–receptor interactions, using five tumor samples of both subtypes. Results: We identify nine major cell types in all tumors analyzed. Any significant differences in their proportions between MXF and UPS were not found. Further reclusterization of lymphoid cells showed that cytotoxic CD8+ T cell proportion was higher in the MXF samples. In UPS cancer cells, the pathways maintaining extracellular matrix components (including collagens, proteoglycans, and other proteins) were highly active, while MXF cells were characterized by high activity of growth factors and angiogenesis pathways. The ligand–receptor interactions between cancer cells and the microenvironment differed significantly between MXF and UPS. In UPS, CD80 of dendritic cells and macrophages prominently interacted with T cell co-inhibitory CTLA-4 receptors, whereas the activating CD80-CD28 interaction was predominant in MXF. Moreover, in UPS, CD44 and integrins of cytotoxic CD8+ T cells prominently interacted with COL1A1/2, while in MXF CD44, interaction with FN1, COL6A1, and LAMC1 prevailed. Conclusions: Differences were identified between UPS and MFS in the composition of lymphoid cell populations and in the intercellular interactions. This proposes deeper understanding of the biological differences between these sarcoma subtypes and may be important for the development of new therapeutic approaches, although further validation of the findings is required.