LYN kinase and estrogen receptor ERα: involvement in carcinogenesis and potential therapeutic target for tumors

Primary or secondary resistance is an important problem when treating any type of tumor. It is often associated with changes in target genes’ functioning. This raises the question of understanding functional intracellular interactions of genes and proteins in oncological processes and therapeutic resistance occurring. When searching target proteins of targeted therapy, it is necessary to identify biomolecules, participating in cell signaling life, which differ significantly in normal and oncological processes and interact with a large number of pathways. It is also important that these biomolecules are not an artifact of tumor therapy or cell line cultivation, and that it is possible to influence them directly, obtaining complex effect. In addition, it is important to study changes occurring during therapy with the biomolecules, which include proto-oncogene of SRC family kinase LYN and gene of the estrogen receptor α ESR1. All these factors may help to overcome the emerging resistance.Objective – to study the way genes of SRC kinase LYN and estrogen receptor α ESR1 influence oncological processes and occurrence of therapeutic resistance.

Modulation of Splenic B Cell Subsets during Experimental Leishmania donovani Infection in BALB/c Mice

Sodium antimonials are one of the major and common drugs used against visceral form leishmaniasis (VL). However, the development of drug resistance makes it difficult to manage this disease. Current work investigates the modulation of splenic B cells during experimental infection with antimony-sensitive and -resistant Leishmania donovani infection. Here we phenotypically characterized splenic B cell subsets in BALB/c mice infected with antimony drug-sensitive and -resistant VL strains using flow-cytometry method. In the splenocytes we noticed increased number of Transitional T3 B cells and B1a B cells in drug-resistant VL strain infection. Besides, we also observed alteration in Follicular B cell population of antimony-resistant strain infected mice. Drug-resistant strain induced secretion of elevated level of IL-10 from B1a B cells and IL-6 from Transitional T3 B cell subsets in the splenocytes. Purified splenic B cells from antimony drug-resistant strain infected mice showed decrease in the Lyn kinase gene expression compared to sensitive strain infected and uninfected mice. The current study provides insight into changes in host splenic B-cell subsets during experimental infection with antimony-sensitive and -resistant L. donovani in murine model.

CD36: Hemin interaction axis to control immune responses and cytokine secretion from macrophages involving Lyn kinase.

The intensity and duration of TNF- production are mutually correlated with the level of CD36 expression level. The macrophages exposed to hemin exhibits modulation of non-opsonic phagocytosis of aged RBCs and ability to kill bacteria. Immuno-fluorescence study indicates translocation and sequestration of CD36 within the intracellular storage in the hemin treated macrophages. It in-tern dysregulate the global cytokine secretion from macrophages. CD36 has suitable hemin biophoric environment involving R292, D372 and Q382 to bind and the mutation in biophore residues (R292A, D372A or Q382A) significantly reduced the affinity. Ectopic expression of CD36 in MG63 cells showed several folds increment in cytokines TNF-, MCP-1, RANTES and CCL1 in response to hemin stimulation but no significant amount of cytokines released with mutants (R292A, D372A or Q382A), highlights the relevance of CD36-hemin interaction for immune-dysfunction. Hemin is driving down-stream signalling involving CD36 and subsequent recruitment of adaptor proteins to the cytosolic domain of CD36. Immuno-precipitation of membrane bound CD36 and detection of adaptor proteins indicate change in level of Lyn proteins with CD36 fractions after hemin stimulation to macrophages. The Lyn targeted siRNA restored the phagocytic activity, reduced the secretion of pro-inflammatory cytokine levels clearly suggests the Src family protein Lyn is crucial for CD36-hemin mediated immune dysregulation and cytokine secretion. In summary, hemin-CD36-Lyn cytokine signalling axis could be a contribution factor to severe malaria pathology and prognosis.

Еstrogen receptor α (ESR1) and SRC family kinase (LYN) gene's mutations associated with ovarian cancer endocrine therapy resistance

Recently multiple data accumulated concerning mutations in the ESR1 gene coding estrogen receptor α (mutESR1) and in the LYN gene coding non receptor tyrosine kinase SRC family member (mutLYN) that are associated with endocrine therapy resistance and that could be considered as markers of endocrine therapy efficiency. In case of gynecologic cancers including ovarian cancer the most frequent mutESR1 are ESR1L536H/P/R/V , ESR1Y537S/N/C/H, ESR1D538G that emerge in the course of hormonotherapy especially using aromatase inhibitors. mutLYN including LYNE159K, LYND189Y, LYNK209N, LYNA370T, LYNG418R, LYNA503D are also identified. mutESR1 and mutLYN increase transcriptional activity of estrogen receptor α (ERα) coded with ESR1 gene and catalytic activity of LYN kinase inducing endocrine therapy resistance. Interdependence of ESR1 and LYN genes is revealed at the level of proteins that they code as the kinases of the SRC family including LYN activate ERα-dependent transcription due to the phosphorylation of ERα at Y537 amino-acid residue that is the most frequently mutated in tumors with endocrine therapy resistance. The aim of the review is revealing the clinical correlations of mutESR1 and mutLYN with the ovarian cancer endocrine therapy resistance that opens perspectives of mutESR1 and mutLYN use as new predictive markers of ovarian cancer and development of more efficient anti-tumor medicaments. In the review the information obtained from PubMed database for the last 20 years using the following key words: ESR1, LYN, mutation(s), estrogen receptor α (ERα), LYN kinase, SRC family kinases, ovarian cancer, gynecologic(al) cancer is discussed.

Therapeutic targeting of Lyn kinase to treat chorea-acanthocytosis

Chorea-Acanthocytosis (ChAc) is a devastating, little understood, and currently untreatable neurodegenerative disease caused by VPS13A mutations. Based on our recent demonstration that accumulation of activated Lyn tyrosine kinase is a key pathophysiological event in human ChAc cells, we took advantage of Vps13a−/− mice, which phenocopied human ChAc. Using proteomic approach, we found accumulation of active Lyn, γ-synuclein and phospho-tau proteins in Vps13a−/− basal ganglia secondary to impaired autophagy leading to neuroinflammation. Mice double knockout Vps13a−/− Lyn−/− showed normalization of red cell morphology and improvement of autophagy in basal ganglia. We then in vivo tested pharmacologic inhibitors of Lyn: dasatinib and nilotinib. Dasatinib failed to cross the mouse brain blood barrier (BBB), but the more specific Lyn kinase inhibitor nilotinib, crosses the BBB. Nilotinib ameliorates both Vps13a−/− hematological and neurological phenotypes, improving autophagy and preventing neuroinflammation. Our data support the proposal to repurpose nilotinib as new therapeutic option for ChAc patients.

Targeting Lyn Kinase in Chorea-Acanthocytosis: A Translational Treatment Approach in an Ultra-Rare Disease

ABSTRACTBackgroundChorea-acanthocytosis (ChAc) is a neurodegenerative disease caused by mutations in the VPS13A gene. It is characterized by several neurological symptoms and the appearance of acanthocytes. Elevated tyrosine kinase Lyn activity has been recently identified as one of the key pathophysiological mechanisms and therefore represents a promising drug target.MethodsWe evaluated an individual off-label treatment with the FDA-approved tyrosine kinase inhibitor dasatinib (100 mg/d, 25.8-50.4 weeks) of three ChAc patients. Alongside with a thorough safety monitoring, we assessed motor and non-motor scales (e.g. MDS-UPDRS, UHDRS, quality of life) as well as routine and experimental laboratory parameters (e.g. serum neurofilament, Lyn kinase activity, actin cytoskeleton in red blood cells).ResultsDasatinib appeared to be reasonably safe. The clinical parameters remained stable without significant improvement or deterioration. Regain of deep tendon reflexes was observed in one patient. Creatine kinase, serum neurofilament levels and acanthocyte count did not reveal consistent effects. However, reduction of initially elevated Lyn kinase activity and accumulated autophagy markers as well as partial restoration of actin cytoskeleton was found in red blood cells.DiscussionWe report on the first treatment approach with disease-modifying intention in ChAc. The experimental parameters indicate target engagement in red blood cells, while clinical effects on the central nervous system could not be proven within a rather short treatment time. Limited knowledge on the natural history of ChAc and the lack of appropriate biomarkers remain major barriers for “clinical trial readiness”. Here, we suggest a panel of outcome parameters for future clinical trials in ChAc.