Biology subjects

Sesarman, A.

Publications and source records attributed to Sesarman, A..

5 recordsLinked to original sources

bioRxiv2026

Fibroblast-Enhanced Tumour Microenvironment Signalling Promotes Adaptive Doxorubicin Tolerance in Heterotypic Melanoma Spheroids

Melanoma is an aggressive malignancy that rapidly adapts to therapy. While chemotherapy resistance has traditionally been attributed to tumour-intrinsic mechanisms, growing evidence implicates the tumour microenvironment in shaping drug tolerance. However, few in vitro models capture the stromal complexity needed to study this interaction. We developed two multicellular melanoma spheroid models of increasing stromal complexity: a baseline model of melanoma, endothelial, and macrophage cells (BEM), and a fibroblast-containing counterpart (BEMF), and compared their transcriptional response to doxorubicin. Fibroblast inclusion increased the doxorubicin concentration required to achieve comparable growth inhibition. While untreated BEMF spheroids exhibited only modest baseline transcriptional differences, they showed a profoundly reshaped transcriptional response after doxorubicin exposure, displaying broader and higher-magnitude changes. These responses were characterized by suppression of proliferative and cell-cycle programmes, together with activation of inflammatory, immune-associated, metabolic, and stress-adaptive pathways. Higher-resolution pathway analyses further revealed coordinated attenuation of mitotic progression, checkpoint regulation, homologous recombination repair, and Rho GTPase signalling, consistent with a shift toward stress-adaptive and phenotypically plastic states, rather than classical resistance mechanisms. Transcriptome-derived transcription factor activity inference supported this regulatory rewiring. Integration with curated resistance-associated genes and external transcriptomic datasets demonstrated strong conservation of core transcriptional features across heterogeneous experimental systems, including consistent suppression of proliferation-associated genes and induction of inflammatory signalling programmes. Together, these findings indicate that fibroblasts redirect chemotherapy responses toward a stress-adaptive, persister-like phenotype and establish fibroblast-containing 3D melanoma spheroids as a physiologically relevant platform for studying tumour microenvironment-mediated chemotherapy tolerance and stromal-tumour interactions.

cancer biology↗

bioRxiv2026

Extracellular Vesicles Derived from Activated Dendritic Cells Loaded with Curcumin Promote Early Activation-associated Functional and Molecular Reprogramming of Primary CD8+ T Cells

Extracellular vesicles (EVs) derived from activated dendritic cells (DCs) are promising cell-free mediators capable of shaping CD8+ T-cell responses. However, their early molecular and functional effects on CD8+ T cells remain incompletely characterized, and whether engineering activated DC-derived EVs with immunomodulatory cargo can fine-tune these responses remains largely unexplored. Here, we investigated whether curcumin loading into EVs derived from CpG-activated and peptide-pulsed DC2.4 cells (EV-ACT) modulates early activation of primary CD8+ T cells. EVs were isolated by ultrafiltration coupled with size-exclusion chromatography (UF-SEC) and characterized physicochemically and molecularly. Exploratory proteomic profiling identified an activation-associated EV protein signature enriched in antigen-processing and immune-related pathways. Curcumin loading achieved an encapsulation efficiency of 16.4% while preserving EV properties, and spectral confocal fluorescence microscopy revealed heterogeneous fluorescence emission patterns consistent with distinct EV-associated curcumin microenvironments. Following rapid cellular association, EV-ACT promoted early CD8+ T-cell activation, inducing an effector-like phenotype characterized by increased CD69 expression, TNF- and Granzyme B production, and reduced Bcl-2 levels without compromising cell viability. Unlike free curcumin, EV-mediated curcumin delivery selectively reinforced these immunostimulatory responses by significantly increasing CD69 expression and STAT3 phosphorylation, sustaining early activation-associated functional and molecular reprogramming of primary CD8+ T cells.

cell biology↗

bioRxiv2025

Exploring Mechanisms of Early Acquired Resistance to Doxorubicin in Melanoma in 3D Model

This study investigated the mechanisms underlying early settlement of doxorubicin (DOX) resistance in B16.F10 murine melanoma spheroids, following repeated exposure to a subinhibitory concentration of the drug. Melanoma spheroids were twice treated with DOX for 48h with a 48h recovery period, and changes in viability, growth, gene/protein expression, and enzyme activity were assessed using RNA-seq, RT-qPCR, western blot, protein array, and gelatinase assays. DOX exposure triggered a biphasic response in melanoma spheroids, with the initial exposure downregulating transcripts involved in cell cycle, DNA damage and repair responses, and suppressing of TNF- via NF-{kappa}B and mTORC1 stress response-related signaling pathways, indicating cell cycle arrest, enhanced DNA damage, and apoptosis resistance. Concurrently, upregulation of Notch1, and of angiogenic, adhesion, and ECM remodeling genes and proteins indicated early DOX-adaptive responses aimed at evading checkpoint arrest and increasing cell aggressiveness. A second DOX exposure amplified these responses in melanoma spheroids, leading to upregulation of some genes involved in cell cycle progression, DNA repair damage responses, along with increased Aqp1, VEGF, Ackr3, MMP-2 expression, as well as elevated MMP-9 activity. Our results offer valuable insights into the molecular drivers of chemoresistance, revealing that early DOX-resistance in melanoma arises from adaptive mechanisms that support cell survival through enhanced angiogenesis and cell migration and motility capacity.

cancer biology↗

bioRxiv2024

A QbD strategy to develop curcumin and siRNA co-loaded lipoplexes to combat osteoarthritis-related inflammation and oxidative stress

Chronic knee and lower back pain due to osteoarthritis (OA) has a global prevalence and impacts human well-being by impairing mobility. Oxidative stress and inflammation are key factors in OA pathogenesis and progression. Non-viral gene delivery through liposomes is a promising approach for repairing damaged cartilage tissues. Our study focuses on developing co-loaded lipoplexes for efficient co-delivery of curcumin and therapeutic siRNA. Curcumin downregulates many inflammatory cytokines, scavenges free radicals, and upregulates collagen and aggrecan, therefore reducing pain and helping with regeneration. Quality by Design (QbD) principles guided the development of curcumin-loaded cationic liposomes (CL), which were further used as vectors for therapeutic siRNA in the design of the co-loaded lipoplexes. QbD steps involved risk assessment, Design of Experiments (DoE), and selection of the optimal vector, i.e., optimum curcumin-loaded cationic liposomes (Opt-CL), which would ensure the best transfection efficiency for therapeutic siRNA. The efficiency of Opt-CL was evaluated in both the primary chondrocytes and cell lines, which were induced by oxidative stress and inflammatory conditions. The Opt-CL successfully reduced the oxidative stress levels in both. The Opt-CL were complexed with the IL-6 and IL-8 siRNA to form co-loaded lipoplexes, which efficiently reduced the inflammation in the chondrocytes. These co-loaded lipoplexes effectively transfected chondrocytes with no toxicity and are promising for further testing in OA models. The study has yielded an optimal non-viral vector that could serve as a platform for the incorporation of other lipophilic drugs and negatively charged oligonucleotides for various ailments. HighlightsO_LIUtilization of QbD to screen and optimize critical factors for the development of CL C_LIO_LIDevelopment of proof of concept using the curcumin and luciferase siRNA as the small molecule and oligonucleotide candidates for efficient cell viability and transfection C_LIO_LIEvaluation of cell internalization and gene knockdown in a luciferase-expressing chondrocyte cell line to prove the model efficacy C_LIO_LIIn chondrocytes, the optimized formulation demonstrated the reduction of inflammation and oxidative stress. C_LI

pharmacology and toxicology↗

bioRxiv2021

Remodeling tumor microenvironment by liposomal co-delivery of DMXAA and simvastatin inhibits malignant melanoma progression

Anti-angiogenic therapies for melanoma have not yet been translated into meaningful clinical benefit for patients, due to development of drug-induced resistance in cancer cells, mainly caused by hypoxia-inducible factor 1 (HIF-1) overexpression and enhanced oxidative stress mediated by tumor-associated macrophages (TAMs). Our previous study demonstrated synergistic antitumor actions of simvastatin (SIM) and 5,6-dimethylxanthenone-4-acetic acid (DMXAA) on an in vitro melanoma model via suppression of the aggressive phenotype of melanoma cells and inhibition of TAMs-mediated angiogenesis. Therefore, we took the advantage of long circulating liposomes (LCL) superior tumor targeting capacity to efficiently deliver SIM and DMXAA to B16.F10 melanoma in vivo, with the final aim of improving the outcome of the anti-angiogenic therapy. Thus, we assessed the effects of this novel combined tumor-targeted treatment on s.c. B16.F10 murine melanoma growth and on the production of critical markers involved in tumor development and progression. Our results showed that the combined liposomal therapy inhibited almost totally the growth of melanoma tumors, due to the enhancement of anti-angiogenic effects of LCL-DMXAA by LCL-SIM and induction of a pro-apoptotic state in the tumor microenvironment (TME). These effects were favoured by the partial re-education of TAMs towards a M1 phenotype and maintained via suppression of major invasion and metastasis promoters (HIF-1, pAP-1 c-Jun, and MMPs). Thus, this novel therapy holds the potential to remodel the tumor microenvironment, by suppressing its most important malignant biological capabilities. HighlightsO_LINovel combined liposomal delivery of SIM and DMXAA inhibits melanoma tumor growth C_LIO_LILCL-SIM augments the anti-angiogenic effects of LCL-DMXAA C_LIO_LICombined liposomal therapy inhibits HIF-1/VEGF axis, induces apoptosis and TAM re-education in tumors C_LIO_LIThis novel therapy suppresses the most important malignant capabilities of melanoma C_LI

cancer biology↗