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Kalluri, R.

Publications and source records attributed to Kalluri, R..

At least 19 recordsLinked to original sources

TGF-β2-induced Snail-mediated EndMT signaling relies on both Smad-dependent and independent pathways

Endothelial-to-mesenchymal transition (EndMT) has become a central mechanism in developmental biology, fibrosis, vascular disease, and cancer. We previously reported on an integrated signaling model in which TGF-{beta}2 induces EndMT through coordinated activation of Smad-dependent and Smad-independent signaling pathways converging on Snail, while GSK-3{beta} regulates Snail activity. We performed a systematic figure-by-figure reproducibility analysis of the original publication. Independent studies published between 2011 and 2026 were identified and curated according to predefined inclusion criteria. Each original experimental conclusion was evaluated for independent confirmation. In parallel, selected biochemical experiments were independently reproduced using newly acquired reagents and contemporary Western blot methodologies. Independent publications consistently reproduced each major mechanistic conclusion of the original study, including activation of Smad, ERK, PI3K/AKT, and p38 MAPK signaling, regulation of Snail expression, EndMT-associated marker switching, and GSK-3{beta}-dependent control of Snail activity. Independent laboratory experiments reproduced the principal biochemical findings using contemporary reagents and experimental workflows. The combined literature analysis and independent laboratory replication demonstrate that the mechanistic framework in our previous study has remained reproducible across multiple laboratories, endothelial cell types, disease models, and fifteen years of investigation. This work illustrates a complementary framework for assessing reproducibility that integrates direct experimental replication with cumulative independent validation.

cell biology↗

Engineered extracellular vesicles targeting BACE1 reduces amyloid beta plaque formation in a genetic mouse model of Alzheimer Disease

Alzheimers disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-{beta} (A{beta}) plaques, neurodegeneration, and cognitive decline. {beta}-Site amyloid precursor protein cleaving enzyme 1 (BACE1) catalyzes the rate-limiting step in A{beta} production and remains a therapeutic target for AD. However, effective delivery of RNA therapeutics to the brain remains challenging due to the blood-brain barrier (BBB). Here, we evaluated the feasibility of using clinical-grade mesenchymal stem cell-derived extracellular vesicles (EVs) as systemic carriers for Bace1-targeting small interfering RNA (siRNA) in the 5xFAD mouse model of AD. Engineered EVs crossed the BBB and delivered siRNA cargo to the brain, with uptake observed in both neurons and astrocytes. Systemic therapy with EVs engineered to encapsulate Bace1 siRNA resulted in reduced brain Bace1 protein levels and a decrease in amyloid plaque burden compared with control EVs carrying scrambled siRNA. The reduction was most pronounced in larger, high-intensity plaques, suggesting that Bace1 suppression may preferentially limit plaque growth and maturation. Repeated systemic administration was well tolerated, with no evidence of treatment-associated toxicity. These findings establish a proof-of-concept feasibility for EV-mediated delivery of Bace1-targeting siRNA to the brain and support further development of engineered EVs as a therapeutic platform for neurodegenerative diseases. Future studies incorporating behavioral, molecular, and mechanistic analyses will be required to determine the extent to which Bace1 suppression delivered through EVs can modify disease progression and improve functional outcomes in AD.

cell biology↗

VrySure: A Multi-Task AI Scientific Fraud Detection Platform for Identifying Manipulated and AI-Generated Biomedical Research Images

Integrity of scientific data is critical in biomedical research, where images often serve as primary evidence for experimental observations and conclusions. Advances in image-editing technologies and generative artificial intelligence (AI) have increased the accessibility and realism of visual manipulation, making detection through manual review increasingly challenging. To empower our laboratory researchers to continuously monitor and uphold scientific rigor and data integrity, and serve the global scientific community, we developed VrySure, an easy-to-deploy, AI-driven multi-task platform for automated image-integrity screening in biomedical research. VrySure integrates four detection modules: cross-image transformation detection, within-image copy-move detection, splicing detection in blot and gel images, and AI-generated image detection. The system identifies potentially manipulated images and, when possible, localizes suspicious regions using bounding-box outputs to support downstream verification. To support development and evaluation, we constructed task-specific datasets by combining public biomedical image resources, curated manipulated examples, and synthetic images generated by multiple generative AI systems. We evaluated VrySure using region-level F1 score, recall, precision, false negative rate (FNR), and false discovery rate (FDR) across multiple manipulation categories and compared its performance with two commonly used commercial image-integrity screening platforms under a predefined benchmark protocol. Under the tested conditions, VrySure achieved a higher F1 score and recall, lower FNR, and maintained a low FDR for within-image copy-move detection, splicing detection, and AI-generated image detection, while showing comparable performance in transformation detection. Beyond automated screening, VrySure is designed to support source-data comparison and evidence-based assessment in scientific integrity investigations. By integrating multiple detection capabilities into a unified and scalable workflow, VrySure provides a practical framework to improve the efficiency and consistency of image-integrity screening in biomedical research.

bioinformatics↗

Differential Akt Signaling Induced by Tumstatin and Endostatin in Human Endothelial Cells

Tumstatin and Endostatin are endogenous extracellular matrix-derived inhibitors of angiogenesis generated from the non-collagenous domains of type IV and type XVIII collagens, respectively. Although both molecules suppress angiogenesis and tumor growth in vivo, previous studies demonstrated that they engage distinct endothelial integrin receptors and activate different intracellular signaling pathways. In particular, Tumstatin inhibits endothelial proliferation through suppression of the focal adhesion kinase (FAK)/phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR pathway, whereas Endostatin primarily inhibits endothelial migration through 5{beta}1 integrin-dependent signaling. Here we evaluated a key mechanistic distinction between these two angiogenesis inhibitors by examining Akt phosphorylation in human umbilical vein endothelial cells (HUVEC) cultured on fibronectin. Validating previous reports, recombinant human Tumstatin reduced Akt phosphorylation whereas recombinant human Endostatin did not alter Akt activation. These findings confirm a defining feature of Tumstatin signaling and reinforce the concept that collagen-derived angiogenesis inhibitors regulate endothelial cell behavior through distinct integrin-dependent mechanisms.

Cell Biology↗

Genetic Targeting and Conductance-Based Modeling Reveal Novel Diversity Within Mouse Type II Spiral Ganglion Neurons

Spiral ganglion neurons (SGNs) transmit auditory signals from the cochlea to the brain and are divided into two main types: type I and type II, distinguished by their anatomy and connectivity. However, the function of type II SGNs remains poorly understood due to their scarcity and lack of clear physiological markers. In this study, we use two Cre-dependent fluorescent reporter mouse lines to enhance the identification and targeting of type II SGNs for whole-cell patch-clamp recordings. We reveal a set of distinguishing biophysical features, most notably, the presence of an inactivating potassium current and weaker voltage-gated sodium currents, that clearly separate type II SGNs from their type I counterparts. Additionally, we uncover greater-than-expected heterogeneity among type II SGNs, including variation in size, excitability, and ion channel expression. These features suggest the existence of distinct subtypes of type II SGNs, with potential differences in function. We find that most type II SGNs are relatively unexcitable and incapable of repetitive firing. Instead, they appear to be better suited to integrating sustained signals, potentially supporting roles in detecting cochlear damage or modulating efferent feedback. Additionally, through computational modeling, we demonstrate that removing the inactivation component of the inactivating potassium current specific to type II SGNs allowed repetitive spiking to similar levels seen in type I SGNs, suggesting a crucial role for the current in stifling type II SGN activity. Together, our findings define biophysical signatures that distinguish SGN types and subtypes, offering new insight into their contributions to normal hearing and cochlear pathology. SignificanceThe sensory neurons of the cochlea are divided into type I and type II spiral ganglion neurons. Type I spiral ganglion neurons convey the main features of sound information. The rarer type II spiral ganglion neurons appear to be putative auditory nociceptors, responding to cochlear damage. By combining genetic tools, electrical activity recordings, and computational models, we demonstrate that type I and type II spiral ganglion neurons have distinctive ion channel profiles and firing properties. Furthermore, we report previously undescribed ion channel diversity within the type II spiral ganglion neuron population, suggesting varied functions. Our results highlight the parallels between type II spiral ganglion neurons and somatosensory nociceptors and provide a framework for selectively targeting distinct auditory neuron populations.

neuroscience↗

Oncogenic KRAS regulates secretion of extracellular vesicles and surface membrane charge via regulation of phosphatidylserine in pancreatic cancer

Extracellular vesicles (EVs) have the potential to be used as a liquid biopsy for cancer detection and treatment response assessment. Although the potential of EVs as disease-specific biomarkers has been promising, the rapid and specific enrichment of EVs from body fluids in the clinical setting remains challenging. To address this limitation, we developed a Microfluidic Electrophoresis (MEP) device, that allows label-free enrichment of EVs based on charge from the serum of patients with pancreatic cancer (PaCa). The ability of MEP to enrich anionic EVs was validated using cell line-derived EVs and PaCa serum-derived EVs. We observed a positive correlation between the KRAS status, secretion of EVs, and net negative zeta potential ({zeta}-potential) of EVs. Further analyses identified phosphatidylserine (PS) and extraluminal DNA as molecular determinants of the enhanced anionic nature of PaCa-derived EVs. Overall, this work introduces a new microfluidic device to enrich cancer EVs in circulation with potential for further rapid detection of PaCa.

bioengineering↗

Inhibitors of oncogenic Kras specifically prime CTLA4 blockade to transcriptionally reprogram Tregs and overcome resistance to suppress pancreas cancer

Lack of sustained response to oncogenic Kras (Kras*) inhibition in preclinical models and patients with pancreatic ductal adenocarcinoma (PDAC) emphasizes the need to identify impactful synergistic combination therapies to achieve robust clinical benefit. Kras* targeting results in an influx of T cell infiltrates including Tregs, effector CD8+ T cells and exhausted CD8+ T cells expressing several immune checkpoint molecules in PDAC. Here, we probe whether the T cell influx induced by different Kras* inhibitors enable a therapeutic window to prime adaptive immune response in PDAC. Here we report a specific synergy between KrasG12D allele specific inhibitor, MRTX1133 or multi-selective pan-RAS inhibitor, RMC-6236 and anti-CTLA4 immune checkpoint blockade. In contrast, attempted therapeutic combination with multiple other immune checkpoint inhibitors, including anti-PD1, anti-Tim3, anti-Lag3, anti-Vista and anti-4-1BB agonist antibody failed due to compensatory mechanisms mediated by other checkpoints on exhausted CD8+ T cells. Specifically, anti-CTLA4 therapy in Kras* targeted PDAC transcriptionally reprograms effector T regs to a naive phenotype, reverses CD8+ T cell exhaustion and is associated with recruitment of tertiary lymphoid structures (TLS) containing follicular B cells, interferon (IFN)- stimulated/ activated B cells, plasma cells and germinal center B cells to functionally enable efficacy of immunotherapy with long-term survival. In this regard, inhibition of the TLS with lymphotoxin-{beta} inhibitor (LTBi) or direct B cell depletion reversed the survival benefit conferred by the combination therapy and highlights the function of TLS in generating productive anti-tumor immune responses. Further, single cell ATAC sequencing analysis revealed that transcriptional reprogramming of Tregs is epigenetically regulated by downregulation of AP-1 family of transcription factors including Fos, Fos-b, Jun-b, Jun-d in the IL-35 promoter region. This study reveals an actionable vulnerability in the adaptive immune response in Kras* targeted PDAC with relevant clinical implications.

cancer biology↗

Inducible, virus-free direct lineage reprogramming enhances scalable generation of human inner ear hair cell-like cells

Mammalian inner ear sensory hair cells are highly sensitive to environmental stress and do not regenerate, making hearing loss progressive and permanent. The paucity and extreme inaccessibility of these cells hinder the development of regenerative and otoprotective strategies, Direct lineage reprogramming to generate large quantities of hair cell-like cells in vitro offers a promising approach to overcome these experimental bottlenecks. Previously, we identified four transcription factors--Six1, Atoh1, Pou4f3, and Gfi1 (SAPG)--capable of converting mouse embryonic fibroblasts, adult tail tip fibroblasts, and postnatal mouse supporting cells into induced hair cell-like cells through retroviral or lentiviral transduction (Menendez et al., 2020). Here, we developed a virus-free, inducible system using a stable human induced pluripotent stem (iPS) cell line carrying doxycycline-inducible SAPG. Our inducible system significantly increases reprogramming efficiency compared to retroviral methods, achieving a [~]19-fold greater conversion to a hair cell fate in half the time. Immunostaining, Western blot, and single-nucleus RNA-seq analyses confirm the expression of hair cell-specific markers and activation of hair cell gene networks in reprogrammed cells. The reprogrammed hair cells closely resemble developing fetal hair cells, as evidenced by comparison with a human fetal inner ear dataset. Electrophysiological analysis reveals that the induced hair cell-like cells exhibit diverse voltage-dependent ion currents, including robust, quick-activating, slowly inactivating currents characteristic of primary hair cells. This virus-free approach improves scalability, reproducibility, and the modeling of hair cell differentiation, offering significant potential for hair cell regenerative strategies and preclinical drug discovery targeting ototoxicity and otoprotection.

developmental biology↗

CDK8 remodels the tumor microenvironment to resist the therapeutic efficacy of targeted KRASG12D inhibition in pancreatic ductal adenocarcinoma

Mutations in KRAS are a dominant driver of pancreatic ductal adenocarcinoma (PDAC), with over 40% of PDAC patients presenting with KRASG12D mutations. The recent development of small molecule inhibitors targeting KRASG12D has enabled targeting of mutant KRAS signaling and suppression of PDAC; however, the contribution of the tumor microenvironment (TME) to the sustained therapeutic efficacy of KRASG12D inhibition and mechanism/s of resistance to KRASG12D suppression remain to be elucidated. Here, we employed spatial transcriptomics, single cell RNA sequencing, and CODEX-based spatial proteomics to evaluate cancer cell intrinsic and extrinsic responses to KRASG12D inhibition with MRTX1133. While KRASG12D inhibition initially increases CD11c+ cells with impactful T cell infiltration within proximity to cancer cells, long-term treatment with MRTX1133 resulted in reversal of the immune responses leading to KRASG12D therapy resistance promoted by CDK8, a multiprotein mediator complex associated kinase. CDK8 imparts resistance in part through induction of downstream CXCL2 chemokine secretion, inhibition of FAS expression, and remodeling of the TME to promote immune evasion. Targeting CDK8 by itself and in combination with CTLA-4 immunotherapy overcomes resistance to KRASG12D inhibition with prolonged survival with translational implications.

cancer biology↗

Vestibular afferent neurons develop normally in the absence of quantal/glutamatergic input

The vestibular nerve is comprised of neuron sub-groups with diverse functions related to their intrinsic biophysical properties. This diversity is partly due to differences in the types and numbers of low-voltage-gated potassium channels found in the neurons membranes. Expression for some low-voltage gated ion channels like KCNQ4 is upregulated during early post-natal development; suggesting that ion channel composition and neuronal diversity may be shaped by hair cell activity. This idea is consistent with recent work showing that glutamatergic input from hair cells is necessary for the normal diversification auditory neurons. To test if biophysical diversity is similarly dependent on glutamatergic input in vestibular neurons, we examined the maturation of the vestibular epithelium and ganglion neurons in Vglut3-ko mice whose hair cell synapses lack glutamate. Despite lacking glutamatergic input, the knockout mice showed no notable balance deficits and crossed challenging balance beams with little difficulty. Immunolabeling of the Vglut3-ko vestibular epithelia showed normal development as indicated by an identifiable striolar zone with calyceal terminals labeled by molecular marker calretinin, and normal expression of KCNQ4 by the end of the second post-natal week. We found similar numbers of Type I and Type II hair cells in the knockout and wildtype animals, regardless of epithelial zone. Thus, the presumably quiescent Type II hair cells are not cleared from the epithelium. Patch-clamp recordings showed that biophysical diversity of vestibular ganglion neurons in the Vglut3-ko mice is comparable to that found in wildtype controls, with a similar range firing patterns at both immature and juvenile ages. However, our results suggest a subtle biophysical alteration to the largest ganglion cells (putative somata of central zone afferents); those in the knockout had smaller net conductance and were more excitable than those in the wild type. Thus, unlike in the auditory nerve, glutamatergic signaling is unnecessary for producing biophysical diversity in vestibular ganglion neurons. And yet, because the input signals from vestibular hair cells are complex and not solely reliant on quantal release of glutamate, whether diversity of vestibular ganglion neurons is simply hardwired or regulated by a more complex set of input signals remains to be determined.

neuroscience↗

Development of an engineered extracellular vesicles-based vaccine platform for combined delivery of mRNA and protein to induce functional immunity

mRNA incorporated in lipid nanoparticles (LNPs) became a new class of vaccine modality for induction of immunity against COVID-19 and ushered in a new era in vaccine development. Here, we report a novel, easy-to-execute, and cost effective engineered extracellular vesicles (EVs)-based combined mRNA and protein vaccine platform (EVX-M+P vaccine) and explore its utility in proof-of-concept immunity studies in the settings of cancer and infectious disease. As a first example, we engineered EVs to contain ovalbumin mRNA and protein (EVOvaM+P) to serve as cancer vaccine against ovalbumin-expressing melanoma tumors. EVOvaM+P administration to mice with established melanoma tumors resulted in tumor regression associated with effective humoral and adaptive immune responses. As a second example, we generated engineered EVs, natural nanoparticle carriers shed by all cells, that contain mRNA and protein Spike (S) protein to serve as a combined mRNA and protein vaccine (EVSpikeM+P vaccine) against SARS-CoV-2 infection. EVSpikeM+P vaccine administration in mice and baboons elicited robust production of neutralizing IgG antibodies against RBD (receptor binding domain) of S protein and S protein specific T cell responses. Our proof-of-concept study describes a new platform with an ability for rapid development of combination mRNA and protein vaccines employing EVs for deployment against cancer and other diseases.

immunology↗

Single extracellular vesicle imaging and computational analysis identifiesinherent architectural heterogeneity

Evaluating the heterogeneity of extracellular vesicles (EVs) is crucial for unraveling their complex actions and biodistribution. Here, we identify consistent architectural heterogeneity of EVs using cryogenic transmission electron microscopy (cryo-TEM) which has an inherent ability to image biological samples without harsh labeling methods and while preserving their native conformation. Imaging EVs isolated using different methodologies from distinct sources such as cancer cells, normal cells, and body fluids, we identify a structural atlas of their dominantly consistent shapes. We identify EV architectural attributes by utilizing a segmentation neural network model. In total, 7,576 individual EVs were imaged and quantified by our computational pipeline. Across all 7,576 independent EVs, the average eccentricity was 0.5366, and the average equivalent diameter was 132.43 nm. The architectural heterogeneity was consistent across all sources of EVs, independent of purification techniques, and compromised of single spherical (S. Spherical), rod-like or tubular, and double shapes. This study will serve as a reference foundation for high-resolution EV images and offer insights into their potential biological impact.

bioengineering↗

Engineered immunomodulatory extracellular vesicles derived from epithelial cells acquire capacity for positive and negative T cell co-stimulation in cancer and autoimmunity

Extracellular vesicles (EVs) are generated by all cells and systemic administration of allogenic EVs derived from epithelial and mesenchymal cells have been shown to be safe, despite carrying an array of functional molecules, including thousands of proteins. To address whether epithelial cells derived EVs can be modified to acquire the capacity to induce immune response, we engineered 293T EVs to harbor the immunomodulatory CD80, OX40L and PD-L1 molecules. We demonstrated abundant levels of these proteins on the engineered cells and EVs. Functionally, the engineered EVs efficiently elicit positive and negative co-stimulation in human and murine T cells. In the setting of cancer and auto-immune hepatitis, the engineered EVs modulate T cell functions and alter disease progression. Moreover, OX40L EVs provide additional benefit to anti-CTLA-4 treatment in melanoma-bearing mice. Our work provides evidence that epithelial cell derived EVs can be engineered to induce immune responses with translational potential to modulate T cell functions in distinct pathological settings.

cancer biology↗

Rapid and high yield isolation of extracellular vesicles with purity by application of size exclusion fast performance liquid chromatography.

Extracellular Vesicles (EVs) have emerged as potential biomarkers for diagnosing a range of diseases without invasive procedures. Extracellular vesicles also offer an advantage compared to synthetic vesicles, for delivery of various drugs. However, limitations in segregating EVs from soluble proteins have led to inconsistent EV retrieval rates with low levels of purity. Here, we report a new high-yield (>95%) and rapid (<20 min) EV isolation method called Size Exclusion - Fast Performance Liquid Chromatography (SE-FPLC). We show SE-FPLC can effectively isolate EVs from multiple sources including EVs derived from human and mouse cells and serum. The results indicate that SE-FPLC can successfully remove highly abundant protein contaminants such as albumin and lipoprotein complexes, which can represent a major hurdle in large scale isolation of EVs for clinical translation. Additionally, the high-yield nature of SE- FPLC allows for easy industrial upscaling of extracellular vesicles production for various clinical utilities. Moreover, SE-FPLC enables analysis of very small volumes of blood for use in point-of-care diagnostics in the clinic. Collectively, SE-FPLC offers many advantages over current EV isolation methods and offers rapid clinical utility potential.

bioengineering↗

A novel machine learning algorithm picks proteome signature to specifically identify cancer exosomes

Non-invasive early cancer diagnosis remains challenging due to the low sensitivity and specificity of current diagnostic approaches. Exosomes are membrane-bound nanovesicles secreted by all cells that contain DNA, RNA, and proteins that are representative of the parent cells. This property, along with the abundance of exosomes in biological fluids makes them compelling candidates as biomarkers. However, a rapid and flexible exosome-based diagnostic method to distinguish human cancers across cancer types in diverse biological fluids is yet to be defined. Here, we describe a novel machine learning-based computational method to distinguish cancers using a panel of proteins associated with exosomes. Employing datasets of exosome proteins from human cell lines, tissue, plasma, serum and urine samples from a variety of cancers, we identify Clathrin Heavy Chain (CLTC), Ezrin, (EZR), Talin-1 (TLN1), Adenylyl cyclase-associated protein 1 (CAP1) and Moesin (MSN) as highly abundant universal biomarkers for exosomes and define three panels of pan-cancer exosome proteins that distinguish cancer exosomes from other exosomes and aid in classifying cancer subtypes employing random forest models. All the models using proteins from plasma, serum, or urine-derived exosomes yield AUROC scores higher than 0.91 and demonstrate superior performance compared to Support Vector Machine, K Nearest Neighbor Classifier and Gaussian Naive Bayes. This study provides a reliable protein biomarker signature associated with cancer exosomes with scalable machine learning capability for a sensitive and specific non-invasive method of cancer diagnosis.

bioinformatics↗

Antigen-presenting type-I conventional dendritic cells facilitate curative checkpoint blockade immunotherapy in pancreatic cancer

Inflammation and tissue damage associated with pancreatitis can precede or occur concurrently with pancreatic ductal adenocarcinoma (PDAC). We demonstrate that in PDAC coupled with pancreatitis (ptPDAC), antigen-presenting type-I conventional dendritic cells (cDC1s) are specifically activated. Immune checkpoint blockade therapy (iCBT) leads to cytotoxic CD8+ T cell activation and eradication of ptPDAC with restoration of lifespan even upon PDAC re-challenge. Such eradication of ptPDAC was reversed following specific depletion of dendritic cells. Employing PDAC antigen-loaded cDC1s as a vaccine, immunotherapy-resistant PDAC was rendered sensitive to iCBT with a curative outcome. Analysis of the T-cell receptor (TCR) sequences in the tumor infiltrating CD8+ T cells following cDC1 vaccination coupled with iCBT identified unique CDR3 sequences with potential therapeutic significance. Our findings identify a fundamental difference in the immune microenvironment and adaptive immune response in PDAC concurrent with, or without pancreatitis, and provides a rationale for combining cDC1 vaccination with iCBT as a potential treatment option.

cancer biology↗

Oncogenic KrasG12D specific non-covalent small molecule inhibitor reprograms tumor microenvironment and reverses early precursor lesions and in combination with immunotherapy regresses advanced PDAC in a CD8+ T cells dependent manner

Pancreatic ductal adenocarcinoma (PDAC) is associated with mutations in Kras, a known oncogenic driver of PDAC; and the KRASG12D mutation is present in nearly half of PDAC patients. Recently, a non-covalent small molecule inhibitor (MRTX1133) was identified with specificity to the KrasG12D mutant protein. Here we explore the impact of KrasG12D inhibition by MRTX1133 on advanced PDAC and its influence on the tumor microenvironment. Employing different orthotopic xenograft and syngeneic tumor models, eight different PDXs, and two different autochthonous genetic models, we demonstrate that MRTX1133 reverses early PDAC growth, increases intratumoral CD8+ effector T cells, decreases myeloid infiltration, and reprograms cancer associated fibroblasts. Autochthonous genetic mouse models treated with MRTX1133 leads to regression of both established PanINs and advanced PDAC. Regression of advanced PDAC requires CD8+ T cells and immune checkpoint blockade therapy (iCBT) synergizes with MRTX1133 to eradicate PDAC and prolong overall survival. Mechanistically, inhibition of mutant Kras in advanced PDAC and human patient derived organoids (PDOs) induces Fas expression in cancer cells and facilitates CD8+T cell mediated death. These results demonstrate the efficacy of MRTX1133 in different mouse models of PDAC associated with reprogramming of stromal fibroblasts and a dependency on CD8+ T cell mediated tumor clearance. Collectively, this study provides a rationale for a synergistic combination of MRTX1133 with iCBT in clinical trials.

cancer biology↗

Autophagy is associated with survival and resiliency of fibroblasts in long-term decaying post-mortem parenchymal tissue

Fibroblasts are spindle-shaped mesenchymal cells and an abundantly studied cell type that are easy to culture. Their adaptive response in culture conditions allows for use in many different cell biological experiments, including their utility in generating induced pluripotent stem cells. Despite extensive use of fibroblasts in cell and molecular biology and genetics experiments, fundamental evaluation of their resiliency and survival programs, in comparison with other cell types, is undetermined. Here, we demonstrate that fibroblasts exhibit remarkable survival capacity in post-mortem tissue decaying at room temperature and can be cultured from ear, tail tips, kidney, lung, fetal, and mammary tumor tissue after 12-hours of post-mortem tissue decay. Fibroblasts can be cultured from ear and lung tissue after 24-hours, and from ear after up to 120-hours of post-mortem tissue decay. Gene expression profiling of post-mortem lung tissue fibroblasts compared to fresh tissue cultured fibroblasts suggested a transition to a more quiescent phenotype with activation of nutrient scavenging pathways as evidenced by downregulation of genes associated with DNA replication, ribosomes, cell cycle, and spliceosomes as well as upregulation of genes associated metabolism, autophagy, and lysosomes. Measurement of light chain 3B (LC3B)-I/LC3B-II ratio and lysosomal-associated membrane protein (LAMP)-1 indicate that autophagy is increased in post-mortem fibroblasts, with evidence for potential increase in autolysosomes and senescence program. Our study provides evidence for the ability of normal fibroblasts to overcome extreme stress conditions and offers new insights into cell survival mechanisms and aging, with potential utility in tissue regeneration and repair.

cell biology↗