Biology subjects

Pitarresi, J. R.

Publications and source records attributed to Pitarresi, J. R..

8 recordsLinked to original sources

bioRxiv2025

Multiplexed cytokine and antigen mRNA administration generates durable anti-tumor immunity against pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a devastating malignancy characterized by limited therapeutic options for advanced disease. Immunotherapy, in particular, has had dismal success rates in the PDAC due to a tumor microenvironment (TME) that contributes to immune exclusion and poor drug delivery. Many cytokines necessary for Natural Killer (NK) and T cell chemotaxis, activation, and cytotoxicity are absent in the PDAC TME. Despite their early success, cytokine therapies have largely failed in the treatment of solid tumors as a result of the lack of efficacy of single cytokine administration and toxicities from systemic delivery. To overcome these limitations, we designed multiplexed mRNA cocktails encoding diverse interleukins, chemokines, and interferons for intratumoral delivery. Administration of a cytokine-encoding mRNA mixture into mice with orthotopically transplanted PDAC tumors achieved robust yet transient cytokine expression locally in the PDAC TME, leading to NK cell and CD8+ T cell immunity and reduced tumor growth and fibrosis in multiple mouse models. Combining cytokine mRNAs with those encoding tumor-associated antigens further activated CD8+ T cell-mediated tumor control and enhanced survival after just a single dose in PDAC-bearing mice. Remarkably, lipid-based nanoparticle (NP) encapsulation of an all-in-one cytokine and antigen mRNA cocktail allowed safe systemic administration and local delivery of these immunogenic signals to autochthonous PDAC tumors in genetically engineered mouse models, culminating in complete tumor responses in 50% of animals. These results suggest that multiplexed mRNA approaches to delivering cytokine signals and antigens generally absent in the TME could pave the way for an effective immunotherapy for PDAC.

cancer biology↗

bioRxiv2025

HIF2-driven PTHrP Causes Cachexia and Hypercalcemia in Kidney Cancer: Treatment with HIF2 Inhibitors

Kidney cancer frequently causes paraneoplastic syndromes, including hypercalcemia and cachexia, but the underlying mechanisms are incompletely understood. The most common form of kidney cancer, clear cell renal cell carcinoma, is frequently caused by loss of the pVHL tumor suppressor protein and the resulting upregulation of the HIF2 transcription factor. We show that PTHLH, which resides on a ccRCC amplicon on chromosome 12p, is a direct HIF2 transcriptional target in ccRCC. Further, we show that the increased PTHLH expression is both necessary and sufficient for the induction of hypercalcemia and cachexia in preclinical orthotopic cell line tumor models. Consistent with these observations, two different allosteric HIF2 inhibitors, belzutifan and NKT2152, rapidly ameliorated hypercalcemia and cachexia in ccRCC patients, including in some patients who did not exhibit objective tumor shrinkage.

cancer biology↗

bioRxiv2025

Pancreatic cancer cachexia is mediated by PTHrP-driven disruption of adipose de novo lipogenesis

Pancreatic cancer patients have the highest rates and most severe forms of cancer cachexia, yet cachexia etiologies remain largely elusive, leading to a lack of effective intervening therapies. Parathyroid hormone-related protein (PTHrP) has been clinically implicated as a putative regulator of cachexia, with serum PTHrP levels correlating with increased weight loss in PDAC patients. Here we show that cachectic PDAC patients have high expression of tumor PTHrP and use a genetically engineered mouse model to functionally demonstrate that loss of PTHrP blocks cachectic wasting, dramatically extending overall survival. The re-expression of PTHrP in lowly cachectic models is sufficient to induce wasting and reduce survival in mice, which is reversed by the conditional deletion of the PTHrP receptor, Pth1r, in adipocytes. Mechanistically, tumor-derived PTHrP suppresses de novo lipogenesis in adipocytes, leading to a molecular rewiring of adipose depots to promote wasting in the cachectic state. Finally, the pharmacological disruption of the PTHrP-PTH1R signaling axis abrogates wasting, highlighting that a targeted disruption of tumor-adipose crosstalk is an effective means to limit cachexia. STATEMENT OF SIGNIFICANCEPancreatic ductal adenocarcinoma (PDAC) is the prototypical cancer type associated with cancer cachexia, a debilitating wasting syndrome marked by adipose tissue loss and muscle atrophy. Herein, we establish that PTHrP is a tumor-derived factor that facilitates cachexia by downregulating de novo lipogenesis in adipocytes and that blocking PTHrP is an effective means to limit wasting in preclinical mouse models.

cancer biology↗

bioRxiv2025

Hypoxia-induced histone methylation and NF-κB activation in pancreas cancer fibroblasts promote EMT-supportive growth factor secretion

The pancreatic ductal adenocarcinoma (PDAC) tumor microenvironment contains hypoxic tissue subdomains and cancer-associated fibroblasts (CAFs) of multiple subtypes that play tumor-promoting and -restraining roles. Here, we demonstrate that hypoxia promotes an inflammatory-like CAF phenotype and that hypoxic CAFs selectively promote epithelial-mesenchymal transition (EMT) in PDAC cancer cells through growth factor-mediated cell crosstalk. By analyzing patient tumor single-cell transcriptomics and conducting an inhibitor screen, we identified IGF-2 and HGF as specific EMT-inducing growth factors produced by hypoxic CAFs. We further found that reactive oxygen species-activated NF-{kappa}B cooperates with hypoxia-dependent histone methylation to promote IGF-2 and HGF expression in hypoxic CAFs. In lineage-traced autochthonous PDAC mouse tumors, hypoxic CAFs resided preferentially near hypoxic, mesenchymal cancer cells. However, in subcutaneous tumors engineered with hypoxia fate-mapped CAFs, once-hypoxic re-oxygenated CAFs lacked a spatial correlation with mesenchymal cancer cells. Thus, hypoxia promotes reversible CAF-malignant cell interactions that drive EMT through druggable signaling pathways. One-sentence summaryWe show that hypoxic fibroblasts in pancreas cancer leverage histone methylation and ROS-mediated NF-{kappa}B activation to produce growth factors that drive epithelial-mesenchymal transition in malignant cells, demonstrating how tumor stromal features cooperate to initiate a signaling process for disease progression.

cancer biology↗

bioRxiv2024

Mitochondrial Ca2+ controls pancreatic cancer growth and metastasis by regulating epithelial cell plasticity

Endoplasmic reticulum to mitochondria Ca2+ transfer is important for cancer cell survival, but the role of mitochondrial Ca2+ uptake through the mitochondrial Ca2+ uniporter (MCU) in pancreatic adenocarcinoma (PDAC) is poorly understood. Here, we show that increased MCU expression is associated with malignancy and poorer outcomes in PDAC patients. In isogenic murine PDAC models, Mcu deletion (McuKO) ablated mitochondrial Ca2+ uptake, which reduced proliferation and inhibited self-renewal. Orthotopic implantation of MCU-null tumor cells reduced primary tumor growth and metastasis. Mcu deletion reduced the cellular plasticity of tumor cells by inhibiting epithelial-to-mesenchymal transition (EMT), which contributes to metastatic competency in PDAC. Mechanistically, the loss of mitochondrial Ca2+ uptake reduced expression of the key EMT transcription factor Snail and secretion of the EMT-inducing ligand TGF{beta}. Snail re-expression and TGF{beta} treatment rescued deficits in McuKO cells and restored their metastatic ability. Thus, MCU may present a therapeutic target in PDAC to limit cancer-cell-induced EMT and metastasis.

cancer biology↗

bioRxiv2023

Nanoparticle delivery of innate immune agonists combines with senescence-inducing agents to mediate T cell control of pancreatic cancer

Pancreatic ductal adenocarcinoma has quickly risen to become the 3rd leading cause of cancer-related death. This is in part due to its fibrotic tumor microenvironment (TME) that contributes to poor vascularization and immune infiltration and subsequent chemo- and immunotherapy failure. Here we investigated an innovative immunotherapy approach combining local delivery of STING and TLR4 innate immune agonists via lipid-based nanoparticles (NPs) co-encapsulation with senescence-inducing RAS-targeted therapies that can remodel the immune suppressive PDAC TME through the senescence-associated secretory phenotype. Treatment of transplanted and autochthonous PDAC mouse models with these regimens led to enhanced uptake of NPs by multiple cell types in the PDAC TME, induction of type I interferon and other pro-inflammatory signaling, increased antigen presentation by tumor cells and antigen presenting cells, and subsequent activation of both innate and adaptive immune responses. This two-pronged approach produced potent T cell-driven and Type I interferon-dependent tumor regressions and long-term survival in preclinical PDAC models. STING and TLR4-mediated Type I interferon signaling were also associated with enhanced NK and CD8+ T cell immunity in human PDAC. Thus, combining localized immune agonist delivery with systemic tumor-targeted therapy can synergize to orchestrate a coordinated innate and adaptive immune assault to overcome immune suppression and activate durable anti-tumor T cell responses against PDAC. SUMMARYCombining senescence-inducing MEK and CDK4/6 inhibitors with nanoparticle delivery of STING and TLR4 agonists leads to interferon-driven and cytotoxic T cell-mediated PDAC control.

cancer biology↗

bioRxiv2023

The mitochondrial Ca2+ channel MCU is critical for tumor growth by supporting cell cycle progression and proliferation

The mitochondrial uniporter (MCU) Ca2+ ion channel represents the primary means for Ca2+ uptake into mitochondria. Here we employed in vitro and in vivo models with MCU genetically eliminated to understand how MCU contributes to tumor formation and progression. Transformation of primary fibroblasts in vitro was associated with increased MCU expression, enhanced mitochondrial Ca2+ uptake, suppression of inactivating-phosphorylation of pyruvate dehydrogenase, a modest increase of basal mitochondrial respiration and a significant increase of acute Ca2+-dependent stimulation of mitochondrial respiration. Inhibition of mitochondrial Ca2+ uptake by genetic deletion of MCU markedly inhibited growth of HEK293T cells and of transformed fibroblasts in mouse xenograft models. Reduced tumor growth was primarily a result of substantially reduced proliferation and fewer mitotic cells in vivo, and slower cell proliferation in vitro associated with delayed progression through S-phase of the cell cycle. MCU deletion inhibited cancer stem cell-like spheroid formation and cell invasion in vitro, both predictors of metastatic potential. Surprisingly, mitochondrial matrix Ca2+ concentration, membrane potential, global dehydrogenase activity, respiration and ROS production were unchanged by genetic deletion of MCU in transformed cells. In contrast, MCU deletion elevated glycolysis and glutaminolysis, strongly sensitized cell proliferation to glucose and glutamine limitation, and altered agonist-induced cytoplasmic Ca2+ signals. Our results reveal a dependence of tumorigenesis on MCU, mediated by a reliance on mitochondrial Ca2+ uptake for cell metabolism and Ca2+ dynamics necessary for cell-cycle progression and cell proliferation.

cancer biology↗

bioRxiv2022

A histone methylation-MAPK signaling axis drives durable epithelial-mesenchymal transition in hypoxic pancreas cancer

Here, we show that hypoxia drives especially long-lasting epithelial-mesenchymal transition (EMT) in pancreatic ductal adenocarcinoma (PDAC) primarily through a positive-feedback histone methylation-MAPK signaling axis. We find that transformed cells preferentially undergo EMT in hypoxic tumor regions in multiple model systems and that hypoxia drives a cell-autonomous EMT in PDAC cells which, unlike EMT in response to growth factors, can last for weeks. We further demonstrate that hypoxia reduces histone demethylase KDM2A activity, suppresses PP2 family phosphatase expression, and activates MAPKs to post-translationally stabilize histone methyltransferase NSD2, leading to an H3K36me2-dependent EMT in which hypoxia-inducible factors play only a supporting role. This mechanism can be antagonized in vivo by combinations of MAPK inhibitors that may be effective in multi-drug therapies designed to target EMT.

cancer biology↗