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21 result(s) for "Kumar, Shamit"
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Strategic trimodal therapy enhances radiation-induced abscopal response in renal cancer
Background The abscopal effect, tumor regression at distant, non-irradiated sites following localized radiotherapy, is rarely observed, even in immunogenic cancers such as renal cell carcinoma. Current strategies have largely failed to reliably enhance this phenomenon. This study aimed to develop and evaluate a novel therapeutic approach to potentiate the abscopal effect using a combination of tumor-targeted liposomal everolimus and YM155 (EY-L), radiation, and interleukin-2 (IL-2). Methods A trimodal therapy comprising EY-L, localized radiation, and systemic IL-2 was tested in two murine renal cancer models (Renca and LVRCC67) using a bilateral tumor setup to distinguish local and distant tumor responses. The efficacy of the triple therapy was compared to that of single and dual combinations. Downstream analyses including immunohistochemistry, CD8 +  T cell depletion, and spatial transcriptomics were performed to investigate potential mechanisms underlying the observed effects. Results In the Renca model, the EY-L + R + IL-2 triple combination significantly suppressed growth in both irradiated and non-irradiated tumors, demonstrating a robust enhancement of the abscopal effect. Dual combinations failed to elicit similar systemic responses, underscoring the necessity of the full triple regimen. Mechanistic analyses revealed increased infiltration of CD8⁺ T cells and reduced CD163 +  macrophages in non-irradiated tumors, suggesting that enhanced systemic anti-tumor immunity mediates the effect. The LVRCC67 model showed similar trends, however the effects were modest, likely attributable to difference in immune responsiveness. Conclusion This study presents a novel and effective strategy to induce the abscopal effect through a synergistic combination of targeted drug delivery, radiotherapy, and immunotherapy. The approach offers strong translational potential for improving radioimmunotherapy outcomes in renal and potentially other immunogenic cancers.
Co-delivery of everolimus and vinorelbine via a tumor-targeted liposomal formulation inhibits tumor growth and metastasis in RCC
Renal cell carcinoma (RCC) is notorious for its resistance towards chemotherapy and radiation therapy in general. Combination therapy is often helpful in alleviating the resistance mechanisms by targeting multiple signaling pathways but is usually more toxic than monotherapy. Co-encapsulation of multiple therapeutic agents in a tumor-targeted drug delivery platform is a promising strategy to mitigate these limitations. A tumor-targeted liposomal formulation was prepared using phospholipids, cholesterol, DSPE-(PEG) -OMe and a proprietary tumor-targeting-peptide (TTP)-conjugated lipopeptide. An efficient method was optimized to encapsulate everolimus and vinorelbine in this liposomal formulation. Single drug-loaded liposomes were also prepared for comparison. Finally, the drug-loaded liposomes were tested in vitro and in vivo in two different RCC cell lines. The tumor-targeted liposomal formulation demonstrated excellent tumor-specific uptake. The dual drug-loaded liposomes exhibited significantly higher growth inhibition in vitro compared to the single drug-loaded liposomes in two different RCC cell lines. Similarly, the dual drug-loaded liposomes demonstrated significantly higher suppression of tumor growth compared to the single drug-loaded liposomes in two different subcutaneous RCC xenografts. In addition, the dual drug-loaded liposomes instigated significant reduction in lung metastasis in those experiments. Taken together, this study demonstrates that co-delivery of everolimus and vinorelbine with a tumor-targeted liposomal formulation is an effective approach to achieve improved therapeutic outcome in RCC.
Targeting mTOR and survivin concurrently potentiates radiation therapy in renal cell carcinoma by suppressing DNA damage repair and amplifying mitotic catastrophe
Background Renal cell carcinoma (RCC) was historically considered to be less responsive to radiation therapy (RT) compared to other cancer indications. However, advancements in precision high-dose radiation delivery through single-fraction and multi-fraction stereotactic ablative radiotherapy (SABR) have led to better outcomes and reduced treatment-related toxicities, sparking renewed interest in using RT to treat RCC. Moreover, numerous studies have revealed that certain therapeutic agents including chemotherapies can increase the sensitivity of tumors to RT, leading to a growing interest in combining these treatments. Here, we developed a rational combination of two radiosensitizers in a tumor-targeted liposomal formulation for augmenting RT in RCC. The objective of this study is to assess the efficacy of a tumor-targeted liposomal formulation combining the mTOR inhibitor everolimus (E) with the survivin inhibitor YM155 (Y) in enhancing the sensitivity of RCC tumors to radiation. Experimental design We slightly modified our previously published tumor-targeted liposomal formulation to develop a rational combination of E and Y in a single liposomal formulation (EY-L) and assessed its efficacy in RCC cell lines in vitro and in RCC tumors in vivo. We further investigated how well EY-L sensitizes RCC cell lines and tumors toward radiation and explored the underlying mechanism of radiosensitization. Results EY-L outperformed the corresponding single drug-loaded formulations E-L and Y-L in terms of containing primary tumor growth and improving survival in an immunocompetent syngeneic mouse model of RCC. EY-L also exhibited significantly higher sensitization of RCC cells towards radiation in vitro than E-L and Y-L. Additionally, EY-L sensitized RCC tumors towards radiation therapy in xenograft and murine RCC models. EY-L mediated induction of mitotic catastrophe via downregulation of multiple cell cycle checkpoints and DNA damage repair pathways could be responsible for the augmentation of radiation therapy. Conclusion Taken together, our study demonstrated the efficacy of a strategic combination therapy in sensitizing RCC to radiation therapy via inhibition of DNA damage repair and a substantial increase in mitotic catastrophe. This combination therapy may find its use in the augmentation of radiation therapy during the treatment of RCC patients.
TRPV4 regulates osteoblast differentiation and mitochondrial function that are relevant for channelopathy
Different ion channels present in the osteoblast regulate the cellular functions including bio-mineralization, a process that is a highly stochastic event. Cellular events and molecular signaling involved in such process is poorly understood. Here we demonstrate that TRPV4, a mechanosensitive ion channel is endogenously present in an osteoblast cell line (MC3T3-E1) and in primary osteoblasts. Pharmacological activation of TRPV4 enhanced intracellular Ca 2+ -level, expression of osteoblast-specific genes and caused increased bio-mineralization. TRPV4 activation also affects mitochondrial Ca 2+ -levels and mitochondrial metabolisms. We further demonstrate that different point mutants of TRPV4 induce different mitochondrial morphology and have different levels of mitochondrial translocation, collectively suggesting that TRPV4-mutation-induced bone disorders and other channelopathies are mostly due to mitochondrial abnormalities. These findings may have broad biomedical implications.
Structural and Functional Perspectives of Optineurin in Autophagy, Immune Signaling, and Cancer
Optineurin (OPTN) is a multifunctional adaptor protein that regulates diverse cellular processes, including inflammatory signaling, autophagy, vesicular trafficking, and immune responses. This multifaceted role of OPTN is made possible by the presence of a complex structure comprising multiple domains that interact with different proteins to exert various functions important for modulating key signaling processes. Mutations in OPTN are linked with several human pathologies including glaucoma, Paget’s disease of bone, Crohn’s disease, and neurodegenerative diseases such as amyotrophic lateral sclerosis, and dementia. Emerging evidence suggests that OPTN has a complex and context-dependent role in cancer biology as well. It is upregulated in pancreatic ductal adenocarcinoma and hepatocellular carcinoma but downregulated in lung and colorectal cancers, indicating its dual role as a potential oncogene or tumor suppressor depending on the cellular environment. Additionally, OPTN plays a critical role in preventing immune evasion in colorectal cancer by maintaining interferon-gamma receptor 1 (IFNGR1) expression and supporting dendritic cell-mediated T-cell priming, thereby enhancing antitumor immune responses. Despite its significance in oncogenic pathways and immune regulation, the therapeutic potential of targeting OPTN in cancer remains largely unexplored. This review aims to provide a comprehensive understanding of OPTN’s pleiotropic functions, highlighting its role in autophagy, inflammation, immune surveillance, and cancer progression. By elucidating its diverse regulatory mechanisms, we seek to encourage further research into the therapeutic implications of OPTN in cancer treatment and immunotherapy.
Lipid Nanoparticle-Mediated RNAi Against GIPC1 Overcomes Chemoresistance in Pancreatic Ductal Adenocarcinoma
Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, characterized by aggressive tumor biology, poor vascularization, dense stromal barriers, and profound resistance to chemotherapy. GAIP-interacting protein C-terminus 1 (GIPC1), a PDZ-domain-containing adaptor protein, is highly overexpressed in PDAC and plays a critical role in tumor progression and chemoresistance. This study aimed to develop and evaluate a novel tumor-targeted liposomal siRNA delivery system (LGIPCsi) to silence GIPC1 and enhance the therapeutic efficacy of gemcitabine (GEM) in PDAC; Methods: LGIPCsi nanoparticles were synthesized and optimized for physicochemical stability, siRNA complexation efficiency, and tumor-targeting capability. Their therapeutic efficacy was assessed using in vitro pancreatic cancer cell models and in vivo orthotopic and patient-derived xenograft (PDX) models of PDAC. Biodistribution, tumor uptake, and antitumor efficacy were evaluated following systemic administration. Combination studies were performed to assess the synergistic effects of LGIPCsi and GEM; Results: GIPC1 silencing significantly sensitized pancreatic cancer cells to GEM, resulting in enhanced inhibition of tumor cell proliferation in vitro. In vivo, systemic administration of LGIPCsi achieved efficient intratumoral delivery of siGIPC1, leading to marked tumor growth suppression. Combination therapy with GEM and LGIPCsi produced synergistic antitumor effects, with substantial tumor regression compared to monotherapy groups. Importantly, no significant systemic toxicity was observed in treated animals; Conclusions: This study identifies GIPC1 as a promising therapeutic target in PDAC and demonstrates that tumor-targeted siRNA nanomedicine can effectively overcome chemoresistance when combined with standard chemotherapy. The LGIPCsi platform offers a rational and translational strategy to enhance treatment efficacy in PDAC through targeted RNAi-based combination therapy.
Vascular Endothelial Growth Factor Receptor-1 Modulates Hypoxia-Mediated Endothelial Senescence and Cellular Membrane Stiffness via YAP-1 Pathways
Hypoxia-induced endothelial cell (EC) dysfunction has been implicated as potential initiators of different pathogenesis, including Alzheimer’s disease and vascular dementia. However, in-depth structural, mechanical, and molecular mechanisms leading to EC dysfunction and pathology need to be revealed. Here, we show that ECs exposed to hypoxic conditions readily enter a senescence phenotype. As expected, hypoxia upregulated the expression of vascular endothelial growth factor (VEGFs) and its receptors (VEGFRs) in the ECs. Interestingly, Knockdown of VEGFR-1 expression prior to hypoxia exposure prevented EC senescence, suggesting an important role of VEGFR-1 expression in the induction of EC senescence. Using atomic force microscopy, we showed that senescent ECs had a flattened cell morphology, decreased membrane ruffling, and increased membrane stiffness, demonstrating unique morphological and nanomechanical signatures. Furthermore, we show that hypoxia inhibited the Hippo pathway Yes-associated protein (YAP-1) expression and knockdown of YAP-1 induced senescence in the ECs, supporting a key role of YAP-1 expression in the induction of EC senescence. And importantly, VEGFR-1 Knockdown in the ECs modulated YAP-1 expression, suggesting a novel VEGFR-1-YAP-1 axis in the induction of hypoxia-mediated EC senescence. In conclusion, VEGFR-1 is overexpressed in ECs undergoing hypoxia-mediated senescence, and the knockdown of VEGFR-1 restores cellular structural and nanomechanical integrity by recovering YAP-1 expression.
Residues of TRPM8 at the Lipid-Water-Interface have Coevolved with Cholesterol Interaction and are Relevant for Diverse Health Disorders
TRPM8 is a non-selective cation channel that is expressed in several tissues and cells and also has a unique property to be activated by low-temperature. In this work, we have analyzed the conservation of amino acids that are present in the lipid-water-interface (LWI) region of TRPM8, the region which experiences a microenvironment near the membrane surface. We demonstrate that the amino acids present in the LWI region are more conserved than the transmembrane or even full-length TRPM8, suggesting strong selection pressure in these residues. TRPM8 also has several conserved cholesterol-binding motifs where cholesterol can bind in different modes and energies. We suggest that mutations and/or physiological conditions can potentially alter these TRPM8-cholesterol complexes and can lead to physiological disorders or even apparently irreversible diseases such as cancer and neurodegeneration.
TRPM8 Regulates Mitochondrial Ca 2+ ‐Dynamics, Temperature and Endoplasmic Reticulum‐Mitochondrial Contact Points in T Cell
TRPM8 is a cold temperature‐sensitive and non‐selective Ca 2+ ‐channel. Previously we have observed that TRPM8 is endogenously expressed and affects T cell activation process. Now, we report that TRPM8 regulates functions of mitochondria and ER, two important sub‐cellular compartments. Pharmacological modulation of TRPM8 and/or due to TCR‐treatment regulates mitochondrial Ca 2+ , ATP, membrane potential, cardiolipin level and mitochondrial temperature in a context‐dependent manner. In addition, TRPM8 alters the relative temperature of mitochondria and ER, ER‐mitochondrial contact points, mainly at the immunological synapse (IS), and thus TRPM8 has the potential to affect the overall cellular functions. Our data suggests both, i.e., the presence and enrichment of TRPM8 in the IS of T cells. We suggest that TRPM8 is a crucial regulator of Ca 2+ ‐signalling in T cells and significantly contributes to Ca 2+ ‐buffering by modulating cellular and sub‐cellular organelle functions. These findings are useful to understand the functions of T cells in different pathological conditions.
TRPM8 Regulates Mitochondrial Ca2+‐Dynamics, Temperature and Endoplasmic Reticulum‐Mitochondrial Contact Points in T Cell
TRPM8 is a cold temperature‐sensitive and non‐selective Ca2+‐channel. Previously we have observed that TRPM8 is endogenously expressed and affects T cell activation process. Now, we report that TRPM8 regulates functions of mitochondria and ER, two important sub‐cellular compartments. Pharmacological modulation of TRPM8 and/or due to TCR‐treatment regulates mitochondrial Ca2+, ATP, membrane potential, cardiolipin level and mitochondrial temperature in a context‐dependent manner. In addition, TRPM8 alters the relative temperature of mitochondria and ER, ER‐mitochondrial contact points, mainly at the immunological synapse (IS), and thus TRPM8 has the potential to affect the overall cellular functions. Our data suggests both, i.e., the presence and enrichment of TRPM8 in the IS of T cells. We suggest that TRPM8 is a crucial regulator of Ca2+‐signalling in T cells and significantly contributes to Ca2+‐buffering by modulating cellular and sub‐cellular organelle functions. These findings are useful to understand the functions of T cells in different pathological conditions.