Biology subjects

Kovacic, B.

Publications and source records attributed to Kovacic, B..

3 recordsLinked to original sources

bioRxiv2026

Photodynamic priming with Vitamin D and ALA-based PDT induces intratumoral immune cell recruitment and signaling pathway activation in murine cutaneous squamous cell carcinoma

Photodynamic therapy (PDT) is effective for early epithelial pre-cancers, yet its efficacy in fully-developed cutaneous squamous cell carcinoma (SCC) is limited by immunosuppression in the tumor microenvironment. Vitamin D (VitD) has emerged as a potential neoadjuvant to enhance photodynamic priming in several cancers. Here, we investigated how VitD pretreatment modulates local and systemic immune responses to aminolevulinic acid-based PDT in two immunocompetent murine SCC models (chronic UV-induced SCC, and subcutaneously implanted PDVC57B cells). VitD combined with PDT significantly amplified hallmarks of immunogenic cell death, including calreticulin and HMGB1 expression, and increased recruitment of neutrophils, macrophages, dendritic cells, and CD8 T cells into tumors. Importantly, VitD+PDT produced a higher M1/M2 macrophage ratio, and reduced the number of exhausted (PD-1 expressing) T cells compared to PDT alone. Immune profiling of blood demonstrated enhanced T-cell activation (CD69) and reduced TIM-3 expression on cytotoxic T cells. Transcriptomic analysis revealed pathway enrichment for interferon-/{gamma} signaling and suppression of pro-tumorigenic epithelial-mesenchymal transition and of angiogenesis after VitD+PDT. Collectively, these findings demonstrate that VitD reprograms the immune response to PDT by enhancing cytotoxic immunity while limiting immunosuppressive features. This suggests an immune-priming strategy to consider, possibly alongside immune checkpoint blockade, for treating cutaneous SCC.

cancer biology↗

bioRxiv2023

NK cells shape the clonal evolution of B-ALL cells by IFN-γ production

The term cancer immunoediting describes the dual role by which the immune system can suppress and promote tumour growth and is divided into three phases: elimination, equilibrium and escape. The role of NK cells has mainly been attributed to the elimination phase. Here we show that NK cells play a role in all three phases of cancer immunoediting. Extended co-culturing of DNA barcoded mouse BCR/ABLp185+ B acute lymphoblastic leukaemia (B-ALL) cells with NK cells allowed for a quantitative measure of NK cell-mediated immunoediting. Whereas most tumour cell clones were efficiently eliminated by NK cells, a certain fraction of tumour cells harboured an intrinsic primary resistance. Furthermore, DNA barcoding revealed tumour cell clones with secondary resistance, which stochastically acquired resistance to NK cells. NK cell cytotoxicity put a selective pressure on B-ALL cells, which led to an outgrowth of primary and secondary resistant tumour cell clones, which were characterised by an IFN-{gamma} signature. Besides well-known regulators of immune evasion, our analysis of NK cell resistant tumour cells revealed the upregulation of genes, including Ly6a, which we found to promote NK cell resistance in leukaemic cells. Translation of our findings to the human system showed that high expression of LY6E on tumour cells impaired the physical interaction with NK cells and led to worse prognosis in leukaemia patients. Our results demonstrate that tumour cells are actively edited by NK cells during the equilibrium phase and use different avenues to escape NK cell-mediated eradication.

cancer biology↗

bioRxiv2018

STAT3 promotes melanoma metastasis by CEBP-induced repression of the MITF pigmentation pathway

Metastatic melanoma is hallmarked by its ability to switch oncogenic MITF expression. Here we tested the impact of STAT3 on melanoma onset and progression in association with MITF expression levels. We established a mouse melanoma model for deleting Stat3 specifically in melanocytes with specific expression of human hyperactive NRASQ61K in an Ink4a deficient background. Mice with tissue specific Stat3 deletion showed an early onset of disease, but displayed significantly diminished lung metastases. Whole genome expression profiling also revealed a reduced invasion phenotype, which was functionally confirmed in 3D melanoma model systems. Notably, loss or knockdown of STAT3 in mouse or human cells resulted in up-regulation of MITF and induction of cell proliferation. Mechanistically we show that STAT3 induced CEBPa/b expression was sufficient to suppress MITF transcription. Epigenetic analysis by ATAC-seq confirmed that STAT3 enabled CEBPa/b binding to the MITF enhancer region thereby silencing it. We conclude that STAT3 is a metastasis driver in melanoma able to antagonize the MITF oncogene via direct induction of CEBP family member transcription facilitating RAS-RAF-driven melanoma metastasis.\n\nList of Abbreviations\n\nATAC-seq, Assay for Transposase-Accessible Chromatin using sequencing; CEBP, CAAT Box Enhancer Binding Protein; CRE, Cre recombinase; EGF, Epidermal Growth Factor; GEO, Gene Expression Omnibus; GSEA, Gene Set Enrichment Analysis; HSC70, Heat Shock 70 kDa protein; IHC, Immunohistochemistry; IL-6, Interleukin-6; JAK, Janus Kinase; MITF, Microphthalmia-Associated Transcription Factor; NSG, NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice; OSM, Oncostatin M; PDGF, Platelet-Derived Growth Factor; pS, phosphoserine; pY, phosphotyrosine; RAS, Rat Sarcoma; RAF, Rapidly Accelerated Fibrosarcoma; RTK, Receptor Tyrosine Kinase; RT-PCR, Reverse Transcription Polymerase Chain Reaction; S100b, Calcium Binding Protein S100 beta; shRNA, short hairpin RNA; SOX10, Sex Determining Region Y-10; STAT, Signal Transducer and Activator of Transcription; TCGA, The Cancer Genome Atlas; TMA, Tissue Micro Array

cancer biology↗