Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer without effective treatments. It is characterized by activating KRAS mutations and p53 alterations. However, how these mutations dysregulate cancer-cell-intrinsic gene programs to influence the immune landscape of the tumor microenvironment (TME) remains poorly understood. Here, we show that p53 R172H establishes an immunosuppressive TME, diminishes the efficacy of immune checkpoint inhibitors (ICIs), and enhances tumor growth. Our findings reveal that the upregulation of the immunosuppressive chemokine Cxcl1 mediates these pro-tumorigenic functions of p53 R172H . Mechanistically, we show that p53 R172H associates with the distal enhancers of the Cxcl1 gene, increasing enhancer activity and Cxcl1 expression. p53 R172H occupies these enhancers in an NF-kappaB-pathway-dependent manner, suggesting NF-kappaB's role in recruiting p53 R172H to the Cxcl1 enhancers. Our work uncovers how a common mutation in a tumor-suppressor transcription factor appropriates enhancers, stimulating chemokine expression and establishing an immunosuppressive TME that diminishes ICI efficacy in PDAC.

To have the desired therapeutic effect, nanomedicines and macromolecular medications must move from the site of injection to the site of action, without having adverse effects. Transvascular transport is a critical step of this navigation, as exemplified by the Enhanced Permeability and Retention (EPR) effect in solid tumors, not found in normal organs. Numerous studies have concluded that passive, diffusion- and convection-based transport predominates over active, cellular mechanisms in this effect. However, recent work using a new approach reevaluated this principle by comparing tumors with or without fixation and concluded the opposite. Here, we address the controversy generated by this new approach by reporting evidence from experimental investigations and computer simulations that separate the contributions of active and passive transport. Our findings indicate that tissue fixation reduces passive transport as well as active transport, indicating the need for new methods to distinguish the relative contributions of passive and active transport.

Introduction Exercise is recommended as an adjunct therapy in cancer, but its effectiveness varies. Our hypothesis is that the benefit depends on the exercise intensity.Methods We subjected mice to low intensity (Li), moderate intensity (Mi) or high intensity (Hi) exercise, or untrained control (Co) groups based on their individual maximal running capacity.Results We found that exercise intensity played a critical role in tumor control. Only Mi exercise delayed tumor growth and reduced tumor burden, whereas Li or Hi exercise failed to exert similar antitumor effects. While both Li and Mi exercise normalized the tumor vasculature, only Mi exercise increased tumor infiltrated CD8+ T cells, that also displayed enhanced effector function (higher proliferation and expression of CD69, INF gamma, GzmB). Moreover, exercise induced an intensity-dependent mobilization of CD8+ T cells into the bloodstream.Conclusion These findings shed light on the intricate relationship between exercise intensity and cancer, with implications for personalized and optimal exercise prescriptions for tumor control.

Purpose: Adding losartan (LOS) to FOLFIRINOX (FFX) che-motherapy followed by chemoradiation (CRT) resulted in 61% R0 surgical resection in our phase II trial in patients with locally advanced pancreatic cancer (LAPC). Here we identify potential mechanisms of benefit by assessing the effects of neoadjuvant LOS on the tumor microenvironment. Experimental Design: We performed a gene expression and immunofluorescence (IF) analysis using archived surgical samples from patients treated with LOS+FFX+CRT (NCT01821729), FFX+CRT (NCT01591733), or surgery upfront, without any neoadjuvant therapy. We also conducted a longitudinal analysis of multiple biomarkers in the plasma of treated patients. Results: In comparison with FFX+CRT, LOS+FFX+CRT down -regulated immunosuppression and pro-invasion genes. Overall sur-vival (OS) was associated with dendritic cell (DC) and antigen presentation genes for patients treated with FFX+CRT, and with immunosuppression and invasion genes or DC-and blood vessel- related genes for those treated with LOS+FFX+CRT. Further-more, LOS induced specific changes in circulating levels of IL-8, sTie2, and TGF-(3. IF revealed significantly less residual disease in lesions treated with LOS+FFX+CRT. Finally, patients with a com-plete/near complete pathologic response in the LOS+FFX+CRT- treated group had reduced CD4+FOXP3+ regulatory T cells (Tregs), fewer immunosuppressive FOXP3+ cancer cells (C-FOXP3), and increased CD8+ T cells in pancreatic ductal adenocarcinoma lesions. Conclusions: Adding LOS to FFX+CRT reduced pro-invasion and immunosuppression-related genes, which were associated with improved OS in patients with LAPC. Lesions from responders in the LOS+FFX+CRT-treated group had reduced Tregs, decreased C-FOXP3 and increased CD8+ T cells. These findings suggest that LOS may potentiate the benefit of FFX+CRT by reducing immunosuppression.

Radiotherapy (RT) is a standard treatment for patients with advanced prostate cancer (PCa). Previous preclinical studies showed that SDF1alpha/CXCR4 axis could mediate PCa metastasis (most often to the bones) and cancer resistance to RT. We found high levels of expression for both SDF1alpha and its receptor CXCR4 in primary and metastatic PCa tissue samples. In vitro analyses using PCa cells revealed an important role of CXCR4 in cell invasion but not radiotolerance. Pharmacologic inhibition of CXCR4 using AMD3100 showed no efficacy in orthotopic primary and bone metastatic PCa models. However, when combined with RT, AMD3100 potentiated the effect of local single-dose RT (12 Gy) in both models. Moreover, CXCR4 inhibition also reduced lymph node metastasis from primary PCa. Notably, CXCR4 inhibition promoted the normalization of bone metastatic PCa vasculature and reduced tissue hypoxia. In conclusion, the SDF1alpha/CXCR4 axis is a potential therapeutic target in metastatic PCa patients treated with RT.

Angiogenesis, the sprouting of new blood vessels from existing vessels, is one of six known mechanisms employed by solid tumors to recruit blood vessels necessary for their initiation, growth, and metastatic spread. The vascular network within the tumor facilitates the transport of nutrients, oxygen, and immune cells and is regulated by pro- and anti-angiogenic factors. Nearly four decades ago, VEGF was identified as a critical factor promoting vascular permeability and angiogenesis, followed by identification of VEGF family ligands and their receptors (VEGFR). Since then, over a dozen drugs targeting the VEGF/VEGFR pathway have been approved for approximately 20 solid tumor types, usually in combination with other therapies. Initially designed to starve tumors, these agents transiently "normalize" tumor vessels in preclinical and clinical studies, and in the clinic, increased tumor blood perfusion or oxygenation in response to these agents is associated with improved outcomes. Nevertheless, the survival benefit has been modest in most tumor types, and there are currently no biomarkers in routine clinical use for identifying which patients are most likely to benefit from treatment. However, the ability of these agents to reprogram the immunosuppressive tumor microenvironment into an immunostimulatory milieu has rekindled interest and has led to the FDA approval of seven different combinations of VEGF/VEGFR pathway inhibitors with immune checkpoint blockers for many solid tumors in the past 3 years. In this review, we discuss our understanding of the mechanisms of response and resistance to blocking VEGF/VEGFR, and potential strategies to develop more effective therapeutic approaches. ©2022 American Association for Cancer Research.

In this multicenter retrospective study, we studied the impact of the concurrent use of renin-angiotensin system inhibitors (RASi) on the outcomes of 229 metastatic renal cell carcinoma (mRCC) patients treated with immunecheckpoint inhibitors (ICI). The findings suggest that RASi could be repurposed to enhance outcomes with ICI in patients with mRCC, which may have a large global impact given their cost-efficacy.Background: Renin-angiotensin system inhibitors (RASi) have been shown to improve outcomes in studies of multiple malignancies by effects on the tumor microenvironment to enhance the immune repertoire and improve drug delivery. Repurposing RASi to treat metastatic renal cell carcinoma (mRCC) in combination with immune-checkpoint inhibitors (ICI) may improve survival coupled with tolerability and cost efficacy. We evaluated the impact of RASi on outcomes in mRCC patients receiving ICI. Methods: This multicenter, retrospective cohort study included mRCC patients treated with ICI with or without RASi. The patients from Dana-Farber Cancer Institute (DFCI) were used as a discovery cohort, and the patients from University of California San Diego (UCSD) were used for validation. Receipt of an ICI (PD1/L1 and/or CTLA-4 inhibitors) was required. RASi use was defined as receipt of a RASi at baseline and for a minimum of 30 days after ICI initiation. For both the discovery and validation cohorts, the primary outcome assessed was overall survival (OS) and the secondary endpoints were time-to-treatment failure (TTF), and objective response rate (ORR). Results: Overall, 229 patients who received an ICI were included: 100 patients from DFCI and 129 patients from UCSD. Concomitant RASi were administered in 30 patients (30%) in the DFCI cohort and 59 (45%) in the UCSD cohort. Median age at ICI initiation was 62.5 years in both cohorts. Median follow-up was 3.8 [IQR 3-5.3] years in the DFCI cohort, and 2.3 [IQR 1.4-3.6] years in the UCSD cohort. In the DFCI cohort, RASi was significantly associated with longer OS (adjusted-HR 0.35 [95% Cl, 0.17-0.70], P = .003) and TTF (adjusted-HR 0.57 [0.36-0.92], P = .02). In the validation cohort, RASi was associated with TTF (adjusted HR, 0.60 [0.39-0.92], P = .02) and not statistically associated with OS (adjusted-HR 0.60 [0.34-1.06], P = .07). The propensity analysis, matching 83 patients from both cohorts receiving RASi while on ICI with 83 who did not, showed that RASi significantly improved OS (HR 0.59 [0.37-0.95], P = .03) and TTF (HR 0.60 [0.43-0.85], P = .0034). Conclusions: RASi was associated with improved OS and TTF in mRCC patients receiving ICI. This provides a rationale for prospective randomized studies combining ICI and RASi in mRCC patients. (C) 2022 Elsevier Inc. All rights reserved.

Nanomedicine offered hope for improving the treatment of cancer but the survival benefits of the clinically approved nanomedicines are modest in many cases when compared to conventional chemotherapy. Metronomic therapy, defined as the frequent, low dose administration of chemotherapeutics - is being tested in clinical trials as an alternative to the conventional maximum tolerated dose (MTD) chemotherapy schedule. Although metronomic chemotherapy has not been clinically approved yet, it has shown better survival than MTD in many preclinical studies. When beneficial, metronomic therapy seems to be associated with normalization of the tumor microenvironment including improvements in tumor perfusion, tissue oxygenation and drug delivery as well as activation of the immune system. Recent preclinical studies suggest that nanomedicines can cause similar changes in the tumor microenvironment. Here, by employing a mathematical framework, we show that both approaches can serve as normalization strategies to enhance treatment. Furthermore, employing murine breast and fibrosarcoma tumor models as well as ultrasound shear wave elastography and contrast-enhanced ultrasound, we provide evidence that the approved nanomedicine Doxil can induce normalization in a dosedependent manner by improving tumor perfusion as a result of tissue softening. Finally, we show that pretreatment with a normalizing dose of Doxil can improve the efficacy of immune checkpoint inhibition.

Our recent studies uncovered a novel GABA signaling pathway in embryonic forebrain endothelial cells that works independently from neuronal GABA signaling and revealed that disruptions in endothelial GABA(A) receptor-GABA signaling from early embryonic stages can directly contribute to the origin of psychiatric disorders. In the GABA(A) receptor beta 3 subunit endothelial cell conditional knockout (Gabrb3(ECKO)) mice, the beta 3 subunit is deleted selectively from endothelial cells, therefore endothelial GABA(A) receptors become inactivated and dysfunctional. There is a reduction in vessel densities and increased vessel morphology in the Gabrb3(ECKO) telencephalon that persists in the adult neocortex. Gabrb3(ECKO) mice show behavioral deficits such as impaired reciprocal social interactions, communication deficits, heightened anxiety, and depression. Here, we characterize the functional changes in Gabrb3(ECKO) mice by evaluating cortical blood flow, examine the consequences of loss of endothelial Gabrb3 on cardiac tissue, and define more in-depth altered behaviors. Red blood cell velocity and blood flow were increased in the cortical microcirculation of the Gabrb3(ECKO) mice. The Gabrb3(ECKO) mice had a reduction in vessel densities in the heart, similar to the brain; exhibited wavy, myocardial fibers, with elongated 'worm-like' nuclei in their cardiac histology, and developed hypertension. Additional alterations in behavioral function were observed in the Gabrb3(ECKO) mice such as increased spontaneous exploratory activity and rearing in an open field, reduced short term memory, decreased ambulatory activity in CLAMS testing, and altered prepulse inhibition to startle, an important biomarker of psychiatric diseases such as schizophrenia. Our results imply that vascular Gabrb3 is a key player in the brain as well as the heart, and its loss in both organs can lead to concurrent development of psychiatric and cardiac dysfunction.

Liver metastasis is a major cause of mortality for patients with colorectal cancer (CRC). Mismatch repair-proficient (pMMR) CRCs make up about 95% of metastatic CRCs, and are unresponsive to immune checkpoint blockade (ICB) therapy. Here we show that mouse models of orthotopic pMMR CRC liver metastasis accurately recapitulate the inefficacy of ICB therapy in patients, whereas the same pMMR CRC tumors are sensitive to ICB therapy when grown subcutaneously. To reveal local, nonmalignant components that determine CRC sensitivity to treatment, we compared the microenvironments of pMMR CRC cells grown as liver metastases and subcutaneous tumors. We found a paucity of both activated T cells and dendritic cells in ICB-treated orthotopic liver metastases, when compared with their subcutaneous tumor counterparts. Furthermore, treatment with Feline McDonough sarcoma (FMS)-like tyrosine kinase 3 ligand (FIt3L) plus ICB therapy increased dendritic cell infiltration into pMMR CRC liver metastases and improved mouse survival. Lastly, we show that human CRC liver metastases and microsatellite stable (MSS) primary CRC have a similar paucity of T cells and dendritic cells. These studies indicate that orthotopic tumor models, but not subcutaneous models, should be used to guide human clinical trials. Our findings also posit dendritic cells as antitumor components that can increase the efficacy of immuno-therapies against pMMR CRC.