Biomechanical remodeling of the microenvironment by stromal caveolin-1 favors tumor invasion and metastasis.

Mechanotransduction is a key determinant of tissue homeostasis and tumor progression. It is driven by intercellular adhesions, cell contractility, and forces generated within the microenvironment and is dependent on extracellular matrix composition, organization, and compliance. We show that caveolin-1 (Cav1) favors cell elongation in three-dimensional cultures and promotes Rho- and force-dependent contraction, matrix alignment, and microenvironment stiffening through regulation of p190RhoGAP. In turn, microenvironment remodeling by Cav1 fibroblasts forces cell elongation. Cav1-deficient mice have disorganized stromal tissue architecture. Stroma associated with human carcinomas and melanoma metastases is enriched in Cav1-expressing carcinoma-associated fibroblasts (CAFs). Cav1 expression in breast CAFs correlates with low survival, and Cav1 depletion in CAFs decreases CAF contractility. Consistently, fibroblast expression of Cav1, through p190RhoGAP regulation, favors directional migration and invasiveness of carcinoma cells in vitro. In vivo, stromal Cav1 remodels peri- and intratumoral microenvironments to facilitate tumor invasion, correlating with increased metastatic potency. Thus, Cav1 modulates tissue responses through force-dependent architectural regulation of the microenvironment.

Cancer treatments as paradoxical catalysts of tumor awakening in the lung.

Much of the fatality of tumors is linked to the growth of metastases, which can emerge months to years after apparently successful treatment of primary tumors. Metastases arise from disseminated tumor cells (DTCs), which disperse through the body in a dormant state to seed distant sites. While some DTCs lodge in pre-metastatic niches (PMNs) and rapidly develop into metastases, other DTCs settle in distinct microenvironments that maintain them in a dormant state. Subsequent awakening, induced by changes in the microenvironment of the DTC, causes outgrowth of metastases. Hence, there has been extensive investigation of the factors causing survival and subsequent awakening of DTCs, with the goal of disrupting these processes to decrease cancer lethality. We here provide a detailed overview of recent developments in understanding of the factors controlling dormancy and awakening in the lung, a common site of metastasis for many solid tumors. These factors include dynamic interactions between DTCs and diverse epithelial, mesenchymal, and immune cell populations resident in the lung. Paradoxically, among key triggers for metastatic outgrowth, lung tissue remodeling arising from damage induced by the treatment of primary tumors play a significant role. In addition, growing evidence emphasizes roles for inflammation and aging in opposing the factors that maintain dormancy. Finally, we discuss strategies being developed or employed to reduce the risk of metastatic recurrence.

Eribulin normalizes pancreatic cancer-associated fibroblasts by simulating selected features of TGFß inhibition.

BACKGROUND: Less than 11% of pancreatic cancer patients survive 5-years post-diagnosis. The unique biology of pancreatic cancer includes a significant expansion of its desmoplastic tumor microenvironment, wherein cancer-associated fibroblasts (CAFs) and their self-produced extracellular matrix are key components. CAF functions are both tumor-supportive and tumor-suppressive, while normal fibroblastic cells are solely tumor-suppressive. Knowing that CAF-eliminating drugs are ineffective and can accelerate cancer progression, therapies that "normalize" CAF function are highly pursued. Eribulin is a well-tolerated anti-microtubule drug used to treat a plethora of neoplasias, including advanced/metastatic cancers. Importantly, eribulin can inhibit epithelial to mesenchymal transition via a mechanism akin to blocking pathways induced by transforming growth factor-beta (TGFß). Notably, canonical TGFß signaling also plays a pivotal role in CAF activation, which is necessary for the development and maintenance of desmoplasia. Hence, we hypothesized that eribulin could modulate, and perhaps "normalize" CAF function. METHODS: To test this premise, we used a well-established in vivo-mimetic fibroblastic cell-derived extracellular matrix (CDM) system and gauged the effects of eribulin on human pancreatic CAFs and cancer cells. This pathophysiologic fibroblast/matrix functional unit was also used to query eribulin effects on CDM-regulated pancreatic cancer cell survival and invasive spread. RESULTS: Demonstrated that intact CAF CDMs modestly restricted eribulin from obstructing pancreatic cancer cell growth. Nonetheless, eribulin-treated CAFs generated CDMs that limited nutrient-deprived pancreatic cancer cell survival, similar to reported tumor-suppressive CDMs generated by TGFß-deficient CAFs. CONCLUSIONS: Data from this study support the central proposed premise suggesting that eribulin could be used as a CAF/matrix-normalizing drug.

Discoidin Domain Receptor 1 (DDR1) Is Necessary for Tissue Homeostasis in Pancreatic Injury and Pathogenesis of Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDA) and chronic pancreatitis are characterized by a dense collagen-rich desmoplastic reaction. Discoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase activated by collagens that can regulate cell proliferation, migration, adhesion, and remodeling of the extracellular matrix. To address the role of DDR1 in PDA, Ddr1-null (Ddr-/-) mice were crossed with the KrasG12D/+; Trp53R172H/+; Ptf1aCre/+ (KPC) model of metastatic PDA. Ddr1-/-; KPC mice progress to differentiated PDA but resist progression to poorly differentiated cancer compared with KPC control mice. Strikingly, severe pancreatic atrophy accompanied tumor progression in Ddr1-/-; KPC mice. To further explore the effects of Ddr1 ablation, Ddr1-/- mice were crossed with the KrasG12D/+; Ptf1aCre/+ neoplasia model and subjected to cerulein-induced experimental pancreatitis. Similar to KPC mice, tissue atrophy was a hallmark of both neoplasia and pancreatitis models in the absence of Ddr1. Compared with controls, Ddr1-/- models had increased acinar cell dropout and reduced proliferation with no difference in apoptotic cell death between control and Ddr1-/- animals. In most models, organ atrophy was accompanied by increased fibrillar collagen deposition, suggesting a compensatory response in the absence of this collagen receptor. Overall, these data suggest that DDR1 regulates tissue homeostasis in the neoplastic and injured pancreas.

CD38 in cancer-associated fibroblasts promotes pro-tumoral activity.

Primary and metastatic melanoma progression are supported by a local microenvironment comprising, inter alia, of cancer-associated fibroblasts (CAFs). We previously reported in orthotropic/syngeneic mouse models that the stromal ectoenzyme CD38 participates in melanoma growth and metastasis. The results presented here suggest that CD38 is a novel regulator of CAFs' pro-tumorigenic functions. Orthotopic co-implantation of CD38 deficient fibroblasts and B16F10 melanoma cells limited tumor size, compared with CD38-expressing fibroblasts. Intrinsically, CAF-CD38 promoted migration of primary fibroblasts toward melanoma cells. Further, in vitro paracrine effects of CAF-CD38 fostered tumor cell migration and invasion as well as endothelial cell tube formation. Mechanistically, we report that CAF-CD38 drives the protein expression of an angiogenic/pro-metastatic signature, which includes VEGF-A, FGF-2, CXCL-12, MMP-9, and HGF. Data suggest that CAF-CD38 fosters tumorigenesis by enabling the production of pro-tumoral factors that promote cell invasion, migration, and angiogenesis.

Sustained hedgehog signaling in medulloblastoma tumoroids is attributed to stromal astrocytes and astrocyte-derived extracellular matrix.

Aberrant activation of the hedgehog (Hh) signaling pathway is associated with the formation of medulloblastoma (MB), the most common malignant pediatric brain tumor. However, tumor cells from human and mouse MB can not be passaged or preserved after being adherently cultured. Moreover, Hh signaling in MB cells is inactivated in such culture. Here we demonstrate that MB cells are capable of forming tumoroids (tumor spheroids) in vitro under optimized conditions, which can be further passaged and cryopreserved. More importantly, MB cells maintain Hh pathway activation and cell proliferation in tumoroids. Our studies further reveal that tumoroids-forming capacity of MB cells relies on astrocytes, a major component of the MB microenvironment. Astrocytes facilitate the formation of MB tumoroids by secreting sonic hedgehog (Shh) and generating astrocyte-derived extracellular matrix. These findings demonstrate the critical role of stromal astrocytes in supporting the survival and proliferation of MB cells in vitro. This study establishes a valid model for long-term culture of primary MB cells, which could be greatly beneficial for future investigation of MB tumorigenicity and the development of improved approaches to treat MB.

Cancer cell chemokines direct chemotaxis of activated stellate cells in pancreatic ductal adenocarcinoma.

The mechanisms by which the extreme desmoplasia observed in pancreatic tumors develops remain unknown and its role in pancreatic cancer progression is unsettled. Chemokines have a key role in the recruitment of a wide variety of cell types in health and disease. Transcript and protein profile analyses of human and murine cell lines and human tissue specimens revealed a consistent elevation in the receptors CCR10 and CXCR6, as well as their respective ligands CCL28 and CXCL16. Elevated ligand expression was restricted to tumor cells, whereas receptors were in both epithelial and stromal cells. Consistent with its regulation by inflammatory cytokines, CCL28 and CCR10, but not CXCL16 or CXCR6, were upregulated in human pancreatitis tissues. Cytokine stimulation of pancreatic cancer cells increased CCL28 secretion in epithelial tumor cells but not an immortalized activated human pancreatic stellate cell line (HPSC). Stellate cells exhibited dose- and receptor-dependent chemotaxis in response to CCL28. This functional response was not linked to changes in activation status as CCL28 had little impact on alpha smooth muscle actin levels or extracellular matrix deposition or alignment. Co-culture assays revealed CCL28-dependent chemotaxis of HPSC toward cancer but not normal pancreatic epithelial cells, consistent with stromal cells being a functional target for the epithelial-derived chemokine. These data together implicate the chemokine CCL28 in the inflammation-mediated recruitment of cancer-associated stellate cells into the pancreatic cancer parenchyma.

A Chemomechanical Model of Matrix and Nuclear Rigidity Regulation of Focal Adhesion Size.

In this work, a chemomechanical model describing the growth dynamics of cell-matrix adhesion structures (i.e., focal adhesions (FAs)) is developed. We show that there are three regimes for FA evolution depending on their size. Specifically, nascent adhesions with initial lengths below a critical value that are yet to engage in actin fibers will dissolve, whereas bigger ones will grow into mature FAs with a steady state size. In adhesions where growth surpasses the steady state size, disassembly will occur until their sizes are reduced to the equilibrium state. This finding arises from the fact that polymerization of adhesion proteins is force-dependent. Under actomyosin contraction, individual integrin bonds within small FAs (i.e., nascent adhesions or focal complexes) must transmit higher loads while the phenomenon of stress concentration occurs at the edge of large adhesion patches. As such, an effective stiffness of the FA-extracellular matrix complex that is either too small or too large will be relatively low, resulting in a limited actomyosin pulling force developed at the edge that is insufficient to prevent disassembly. Furthermore, it is found that a stiffer extracellular matrix and/or nucleus, as well as a stronger chemomechanical feedback, will induce larger adhesions along with a higher level of contraction force. Interestingly, switching the extracellular side from an elastic half-space, corresponding to some widely used in vitro gel substrates, to a one-dimensional fiber (as in the case of cells anchoring to a fibrous scaffold in vivo) does not qualitative change these conclusions. Our model predictions are in good agreement with a variety of experimental observations obtained in this study as well as those reported in the literature. Furthermore, this new model, to our knowledge, provides a framework with which to understand how both intracellular and extracellular perturbations lead to changes in adhesion structure number and size.

Enhanced aggressiveness of benzopyrene-induced squamous carcinomas in transgenic mice overexpressing the proprotein convertase PACE4 (PCSK6).

PACE4 (PCSK6) is a proprotein convertase (PC) capable of processing numerous substrates involved in tumor growth, invasion, and metastasis. Because of the human relevancy of the tobacco-associated carcinogen benzo[a]pyrene (B(a)P) we investigated whether transgenic mice in which this PC is targeted to the epidermis (K5-PACE4) may be more susceptible to B(a)P complete carcinogenesis than wild type (WT) mice. In an in vitro experiment, using cell lines derived from skin tumors obtained after B(a)P treatment, we observed that PACE4 overexpression and activity accounts for an increased proliferation rate, exaggerated sensitivity to the PC inhibitor CMK, and interference with IGF-1R autophosphorylation. Squamous cell carcinomas, obtained from K5-PACE4 mice subjected to complete chemical carcinogenesis, were characterized by a 50% increase in cell proliferation, when compared with similar tumors from WT mice. In addition, tumors from K5-PACE4 mice showed deeper invasion into the underlying dermis. Thus, mice overexpressing PACE4 exhibited tumors of increased growth rate and invasive potential when exposed to the human carcinogen B(a)P, further supporting the significance of PCs in tumor growth and progression.

The wound healing, chronic fibrosis, and cancer progression triad.

For decades tumors have been recognized as "wounds that do not heal." Besides the commonalities that tumors and wounded tissues share, the process of wound healing also portrays similar characteristics with chronic fibrosis. In this review, we suggest a tight interrelationship, which is governed as a concurrence of cellular and microenvironmental reactivity among wound healing, chronic fibrosis, and cancer development/progression (i.e., the WHFC triad). It is clear that the same cell types, as well as soluble and matrix elements that drive wound healing (including regeneration) via distinct signaling pathways, also fuel chronic fibrosis and tumor progression. Hence, here we review the relationship between fibrosis and cancer through the lens of wound healing.

Exploring the potential role of palladin in modulating human CAF/ECM functional units.

Fibroblasts, crucial for maintaining tissue homeostasis, significantly shape the tumor microenvironment (TME). In pancreatic cancer, a highly aggressive malignancy, cancer-associated fibroblast (CAF)/extracellular matrix (ECM) units dominate the TME, influencing tumor initiation, progression, and treatment responses. Palladin, an actin-associated protein, is vital for fibroblast structural integrity and activation, playing a key role in CAF/ECM functionality. Palladin interacts with cytoskeletal proteins such as alpha-actinin (α-Act) and can therefore regulate other proteins like syndecans, modulating cytoskeletal features, cell adhesion, integrin recycling, and signaling. In this review, we propose that targeting the palladin/α-Act/syndecan interaction network could modulate CAF/ECM units, potentially shifting the TME from a tumor-promoting to a tumor-suppressive state. In silico data and reported studies to suggest that stabilizing palladin-α-Act interactions, via excess palladin, influences syndecan functions; potentially modulating integrin endocytosis via syndecan engagement with protein kinase C alpha as opposed to syndecan binding to α-Act. This mechanism can then affect the distribution of active α5ß1-integrin between the plasma membrane and known intracellular vesicular compartments, thereby influencing the tumor-suppressive versus tumor-promoting functions of CAF/ECM units. Understanding these interactions offers likely future therapeutic avenues for stroma normalization in pancreatic and other cancers, aiming to inhibit tumor progression and improve future treatment outcomes.

Fibroblast integrin α11ß1 is a collagen assembly receptor in mechanoregulated fibrillar adhesions.

Solid epithelial cancers with significant desmoplasia are characterized by an excessive deposition of collagen-based matrix, which often supports tumor progression. However, the mechanism of how collagen receptors mediate collagen fibrillogenesis still remains mostly unclear. We show that the collagen-binding integrin α11ß1 can co-localize with tensin-1 and deposit collagen I in human pancreatic ductal adenocarcinoma (PDAC) stroma. In addition to the canonical fibrillar adhesion integrin α5ß1 expressed by human PDAC cancer-associated fibroblasts (CAFs), tensin-1-positive fibrillar adhesions contained α11ß1 but lacked α1ß1 and α2ß1. CAFs lacking α5ß1 expression displayed mechanoregulated and tensin-1 dependent α11ß1 fibrillar adhesions, suggesting independent roles of the two integrins with regards to fibrillar adhesions-based de novo fibrillogenesis. Further, we demonstrate that cell surface-associated collagen I assembly necessitated α11ß1, but not α5ß1 expression. In summary, α11ß1 integrin is a novel component of fibrillar adhesions, which is strategically positioned to mediate de novo collagen fibrillogenesis at the cell surface under pro-fibrotic conditions.

A bioprinted sea-and-island multicellular model for dissecting human pancreatic tumor-stroma reciprocity and adaptive metabolism.

Pancreatic ductal adenocarcinoma (PDAC) presents a formidable clinical challenge due to its intricate microenvironment characterized by desmoplasia and complex tumor-stroma interactions. Conventional models hinder studying cellular crosstalk for therapeutic development. To recapitulate key features of PDAC masses, this study creates a novel sea-and-island PDAC tumor construct (s&i PTC). The s&i PTC consists of 3D-printed islands of human PDAC cells positioned within an interstitial extracellular matrix (ECM) populated by human cancer-associated fibroblasts (CAFs). This design closely mimics the in vivo desmoplastic architecture and nutrient-poor conditions. The model enables studying dynamic tumor-stroma crosstalk and signaling reciprocity, revealing both known and yet-to-be-discovered multicellular metabolic adaptations. Using the model, we discovered the orchestrated dynamic alterations of CAFs under nutrient stress, resembling critical in vivo human tumor niches, such as the secretion of pro-tumoral inflammatory factors. Additionally, nutrient scarcity induces dynamic alterations in the ECM composition and exacerbates poor cancer cell differentiation-features well-established in PDAC progression. Proteomic analysis unveiled the enrichment of proteins associated with aggressive tumor behavior and ECM remodeling in response to poor nutritional conditions, mimicking the metabolic stresses experienced by avascular pancreatic tumor cores. Importantly, the model's relevance to patient outcomes is evident through an inverse correlation between biomarker expression patterns in the s&i PTCs and PDAC patient survival rates. Key findings include upregulated MMPs and key ECM proteins (such as collagen 11 and TGFß) under nutrient-avid conditions, known to be regulated by CAFs, alongside the concomitant reduction in E-cadherin expression associated with a poorly differentiated PDAC state under nutrient deprivation. Furthermore, elevated levels of hyaluronic acid (HA) and integrins in response to nutrient deprivation underscore the model's fidelity to the PDAC microenvironment. We also observed increased IL-6 and reduced α-SMA expression under poor nutritional conditions, suggesting a transition of CAFs from myofibroblastic to inflammatory phenotypes under a nutrient stress akin to in vivo niches. In conclusion, the s&i PTC represents a significant advancement in engineering clinically relevant 3D models of PDAC masses. It offers a promising platform for elucidating tumor-stroma interactions and guiding future therapeutic strategies to improve patient outcomes.

Pancreatic Cancer-Associated Fibroblasts: Where do we go from here?

Pancreatic ductal adenocarcinoma is a deadly disease and is projected to become the second leading cause of cancer-related death by 2030. A major hallmark is the exuberant host response comprising the tumor microenvironment, of which cancer-associated fibroblasts (CAFs) are a prevalent component. Despite the gains in understanding of their heterogeneity and functionality from CAF studies in recent years, there are many unanswered questions surrounding this diverse population of cells. Here we summarize the views of several experts in the field, focusing on the current understanding of CAFs and challenges to address.

Derivation of human primary prostate epithelial cell lines by differentially targeting the CDKN2A locus along with expression of hTERT.

Prostate cancer (PCa) is the most common cancer diagnosed in men worldwide and was the second leading cause of cancer-related deaths in US males in 2022. Prostate cancer also represents the second highest cancer mortality disparity between non-Hispanic blacks and whites. However, there is a relatively small number of prostate normal and cancer cell lines compared to other cancers. To identify the molecular basis of PCa progression, it is important to have prostate epithelial cell (PrEC) lines as karyotypically normal as possible. Our lab recently developed a novel methodology for the rapid and efficient immortalization of normal human PrEC that combines simultaneous CRISPR-directed inactivation of CDKN2A exon 2 (which directs expression of p16INK4A and p14ARF) and ectopic expression of an hTERT transgene. To optimize this methodology to generate immortalized lines with minimal genetic alterations, we sought to target exon 1α of the CDKN2A locus so that p16INK4A expression is ablated while the exons encoding p14ARF remains unaltered. Here we describe the establishment of two cell lines: one with the above-mentioned p16INK4A only loss, and a second line targeting both products in the CDKN2A locus. We characterize the potential lineage origin of these new cell lines along with our previously obtained clones, revealing distinct gene expression signatures. Based on the analyses of protein markers and RNA expression signatures, these cell lines are most closely related to a subpopulation of basal prostatic cells. Given the simplicity of this one-step methodology and the fact that it uses only the minimal genetic alterations necessary for immortalization, it should also be suitable for the establishment of cell lines from primary prostate tumor samples, an urgent need given the limited number of available prostate cancer cell lines.

Derivation of human primary prostate epithelial cell lines by differentially targeting the CDKN2A locus along with expression of hTERT.

Prostate cancer (PCa) is the most common cancer diagnosed in men worldwide and the second leading cause of cancer-related deaths in US males in 2022. Prostate cancer also represents the second highest cancer mortality disparity between non-Hispanic blacks and whites. However, there is a relatively small number of prostate normal and cancer cell lines compared to other cancers. To identify the molecular basis of PCa progression, it is important to have prostate epithelial cell (PrEC) lines as karyotypically normal as possible. Our lab recently developed a novel methodology for the rapid and efficient immortalization of normal human PrEC that combines simultaneous CRISPR-directed inactivation of CDKN2A exon 2 (which directs expression of p16INK4A and p14ARF) and ectopic expression of an hTERT transgene. To optimize this methodology to generate immortalized lines with minimal genetic alterations, we sought to target exon 1α of the CDKN2A locus so that p16INK4A expression is ablated while p14ARF expression remains unaltered. Here we describe the establishment of two cell lines: one with the above-mentioned p16INK4A only loss, and a second line targeting both products in the CDKN2A locus. We characterize the potential lineage origin of these new cell lines along with our previously obtained clones, revealing distinct gene expression signatures. Based on the analyses of protein markers and RNA expression signatures, these cell lines are most closely related to a subpopulation of basal prostatic cells. Given the simplicity of this one-step methodology and the fact that it uses only the minimal genetic alterations necessary for immortalization, it should also be suitable for the establishment of cell lines from primary prostate tumor samples, an urgent need given the limited number of available prostate cancer cell lines.

Pulsed low-dose-rate radiation (PLDR) reduces the tumor-promoting responses induced by conventional chemoradiation in pancreatic cancer-associated fibroblasts.

Pancreatic cancer is becoming increasingly deadly, with treatment options limited due to, among others, the complex tumor microenvironment (TME). This short communications study investigates pulsed low-dose-rate radiation (PLDR) as a potential alternative to conventional radiotherapy for pancreatic cancer neoadjuvant treatment. Our ex vivo research demonstrates that PLDR, in combination with chemotherapy, promotes a shift from tumor-promoting to tumor-suppressing properties in a key component of the pancreatic cancer microenvironment we called CAFu (cancer-associated fibroblasts and selfgenerated extracellular matrix functional units). This beneficial effect translates to reduced desmoplasia (fibrous tumor expansion) and suggests PLDR's potential to improve total neoadjuvant therapy effectiveness. To comprehensively assess this functional shift, we developed the HOST-Factor, a single score integrating multiple biomarkers. This tool provides a more accurate picture of CAFu function compared to individual biomarkers and could be valuable for guiding and monitoring future therapeutic strategies. Our findings support the ongoing NCT04452357 clinical trial testing PLDR safety and TME normalization potential in pancreatic cancer patients. The HOST-Factor will be used in samples collected from this trial to validate its potential as a key tool for personalized medicine in this aggressive disease.

Prognostic and therapeutic implications of tumor-restrictive type III collagen in the breast cancer microenvironment.

Collagen plays a critical role in regulating breast cancer progression and therapeutic resistance. An improved understanding of both the features and drivers of tumor-permissive and -restrictive collagen matrices are critical to improve prognostication and develop more effective therapeutic strategies. In this study, using a combination of in vitro, in vivo and bioinformatic experiments, we show that type III collagen (Col3) plays a tumor-restrictive role in human breast cancer. We demonstrate that Col3-deficient, human fibroblasts produce tumor-permissive collagen matrices that drive cell proliferation and suppress apoptosis in non-invasive and invasive breast cancer cell lines. In human triple-negative breast cancer biopsy samples, we demonstrate elevated deposition of Col3 relative to type I collagen (Col1) in non-invasive compared to invasive regions. Similarly, bioinformatics analysis of over 1000 breast cancer patient biopsies from The Cancer Genome Atlas BRCA cohort revealed that patients with higher Col3:Col1 bulk tumor expression had improved overall, disease-free, and progression-free survival relative to those with higher Col1:Col3 expression. Using an established 3D culture model, we show that Col3 increases spheroid formation and induces the formation of lumen-like structures that resemble non-neoplastic mammary acini. Finally, our in vivo study shows co-injection of murine breast cancer cells (4T1) with rhCol3-supplemented hydrogels limits tumor growth and decreases pulmonary metastatic burden compared to controls. Taken together, these data collectively support a tumor-suppressive role for Col3 in human breast cancer and suggest that strategies that increase Col3 may provide a safe and effective therapeutic modality to limit recurrence in breast cancer patients.

Netrin G1 Ligand is a new stromal immunomodulator that promotes pancreatic cancer.

Understanding pancreatic cancer biology is fundamental for identifying new targets and for developing more effective therapies. In particular, the contribution of the stromal microenvironment to pancreatic cancer tumorigenesis requires further exploration. Here, we report the stromal roles of the synaptic protein Netrin G1 Ligand (NGL-1) in pancreatic cancer, uncovering its pro-tumor functions in cancer-associated fibroblasts and in immune cells. We observed that the stromal expression of NGL-1 inversely correlated with patients' overall survival. Moreover, germline knockout (KO) mice for NGL-1 presented decreased tumor burden, with a microenvironment that is less supportive of tumor growth. Of note, tumors from NGL-1 KO mice produced less immunosuppressive cytokines and displayed an increased percentage of CD8 + T cells than those from control mice, while preserving the physical structure of the tumor microenvironment. These effects were shown to be mediated by NGL-1 in both immune cells and in the local stroma, in a TGF-ß-dependent manner. While myeloid cells lacking NGL-1 decreased the production of immunosuppressive cytokines, NGL-1 KO T cells showed increased proliferation rates and overall polyfunctionality compared to control T cells. CAFs lacking NGL-1 were less immunosuppressive than controls, with overall decreased production of pro-tumor cytokines and compromised ability to inhibit CD8 + T cells activation. Mechanistically, these CAFs downregulated components of the TGF-ß pathway, AP-1 and NFAT transcription factor families, resulting in a less tumor-supportive phenotype. Finally, targeting NGL-1 genetically or using a functionally antagonistic small peptide phenocopied the effects of chemotherapy, while modulating the immunosuppressive tumor microenvironment (TME), rather than eliminating it. We propose NGL-1 as a new local stroma and immunomodulatory molecule, with pro-tumor roles in pancreatic cancer. Statement of Significance: Here we uncovered the pro-tumor roles of the synaptic protein NGL-1 in the tumor microenvironment of pancreatic cancer, defining a new target that simultaneously modulates tumor cell, fibroblast, and immune cell functions. This study reports a new pathway where NGL-1 controls TGF-ß, AP-1 transcription factor members and NFAT1, modulating the immunosuppressive microenvironment in pancreatic cancer. Our findings highlight NGL-1 as a new stromal immunomodulator in pancreatic cancer.

Integrating priorities at the intersection of cancer and neuroscience.

Cancer neuroscience is a rapidly growing multidisciplinary field that conceptualizes tumors as tissues fully integrated into the nervous system. Recognizing the complexity and challenges in this field is of fundamental importance to achieving the goal of translational impact for cancer patients. Our commentary highlights key scientific priorities, optimal training settings, and roadblocks to translating scientific findings to the clinic in this emerging field, aiming to formulate a transformative and cohesive path forward.