Mutant p53 Exploits Enhancers to Elevate Immunosuppressive Chemokine Expression and Impair Immune Checkpoint Inhibitors in Pancreatic Cancer.

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.

Wnt inhibition alleviates resistance to immune checkpoint blockade in glioblastoma.

Wnt signaling plays a critical role in the progression and treatment outcome of glioblastoma (GBM). Here, we identified WNT7b as a heretofore unknown mechanism of resistance to immune checkpoint inhibition (αPD1) in GBM patients and murine models. Acquired resistance to αPD1 was found to be associated with the upregulation of Wnt7b and β-catenin protein levels in GBM in patients and in a clinically relevant, stem-rich GBM model.

Anti-VEGF therapy improves EGFR-vIII-CAR-T cell delivery and efficacy in syngeneic glioblastoma models in mice.

Chimeric antigen receptor (CAR)-T cells have revolutionized the treatment of multiple types of hematological malignancies, but have shown limited efficacy in patients with glioblastoma (GBM) or other solid tumors. This may be largely due to the immunosuppressive tumor microenvironment (TME) that compromises CAR-T cells' delivery and antitumor activity. We previously showed that blocking vascular endothelial growth factor (VEGF) signaling can normalize tumor vessels in murine and human tumors, including GBM, breast, liver, and rectal carcinomas.

Glycocalyx mechanotransduction mechanisms are involved in renal cancer metastasis.

Mammalian cells, including cancer cells, are covered by a surface layer containing cell bound proteoglycans, glycoproteins, associated glycosaminoglycans and bound proteins that is commonly referred to as the glycocalyx. Solid tumors also have a dynamic fluid microenvironment with elevated interstitial flow. In the present work we further investigate the hypothesis that interstitial flow is sensed by the tumor glycocalyx leading to activation of cell motility and metastasis.

Dendritic cell paucity in mismatch repair-proficient colorectal cancer liver metastases limits immune checkpoint blockade efficacy.

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.

FATTY ACID SYNTHESIS IS REQUIRED FOR BREAST CANCER BRAIN METASTASIS.

Brain metastases are refractory to therapies that control systemic disease in patients with human epidermal growth factor receptor 2 (HER2+) breast cancer, and the brain microenvironment contributes to this therapy resistance. Nutrient availability can vary across tissues, therefore metabolic adaptations required for brain metastatic breast cancer growth may introduce liabilities that can be exploited for therapy. Here, we assessed how metabolism differs between breast tumors in brain versus extracranial sites and found that fatty acid synthesis is elevated in breast tumors growing in brain.

Targeting Treg cells with GITR activation alleviates resistance to immunotherapy in murine glioblastomas.

Immune checkpoint blockers (ICBs) have failed in all phase III glioblastoma (GBM) trials. Here, we show that regulatory T (Treg) cells play a key role in GBM resistance to ICBs in experimental gliomas. Targeting glucocorticoid-induced TNFR-related receptor (GITR) in Treg cells using an agonistic antibody (αGITR) promotes CD4 Treg cell differentiation into CD4 effector T cells, alleviates Treg cell-mediated suppression of anti-tumor immune response, and induces potent anti-tumor effector cells in GBM.

In vivo compression and imaging in mouse brain to measure the effects of solid stress.

We recently developed an in vivo compression device that simulates the solid mechanical forces exerted by a growing tumor on the surrounding brain tissue and delineates the physical versus biological effects of a tumor. This device, to our knowledge the first of its kind, can recapitulate the compressive forces on the cerebellar cortex from primary (e.g.

A cerebellopontine angle mouse model for the investigation of tumor biology, hearing, and neurological function in NF2-related vestibular schwannoma.

Neurofibromatosis type II (NF2) is a disease that lacks effective therapies. NF2 is characterized by bilateral vestibular schwannomas (VSs) that cause progressive and debilitating hearing loss, leading to social isolation and increased rates of depression. A major limitation in NF2 basic and translational research is the lack of animal models that allow the full spectrum of research into the biology and molecular mechanisms of NF2 tumor progression, as well as the effects on neurological function.

Obesity promotes resistance to anti-VEGF therapy in breast cancer by up-regulating IL-6 and potentially FGF-2.

Anti-vascular endothelial growth factor (VEGF) therapy has failed to improve survival in patients with breast cancer (BC). Potential mechanisms of resistance to anti-VEGF therapy include the up-regulation of alternative angiogenic and proinflammatory factors. Obesity is associated with hypoxic adipose tissues, including those in the breast, resulting in increased production of some of the aforementioned factors.

A cerebellar window for intravital imaging of normal and disease states in mice.

The cerebellum is a prominent part of the vertebrate hindbrain that is critically involved in the regulation of important body functions such as movement coordination, maintenance of balance and posture, and motor control. Here, we describe a cerebellar window that provides access to the mouse cerebellum for intravital imaging, thereby allowing for a detailed characterization of the dynamic processes in this region of the brain. First, the skull overlying the cerebellum is removed, and then the window is applied to the region of interest.

Heparan sulfate proteoglycans mediate renal carcinoma metastasis.

The surface proteoglycan/glycoprotein layer (glycocalyx) on tumor cells has been associated with cellular functions that can potentially enable invasion and metastasis. In addition, aggressive tumor cells with high metastatic potential have enhanced invasion rates in response to interstitial flow stimuli in vitro. Our previous studies suggest that heparan sulfate (HS) in the glycocalyx plays an important role in this flow mediated mechanostransduction and upregulation of invasive and metastatic potential.

An orthotopic mouse model of hepatocellular carcinoma with underlying liver cirrhosis.

Subcutaneous xenografts have been used for decades to study hepatocellular carcinoma (HCC). These models do not reproduce the specific pathophysiological features of HCCs, which occur in cirrhotic livers that show pronounced necroinflammation, abnormal angiogenesis and extensive fibrosis. As these features are crucial for studying the role of the pathologic host microenvironment in tumor initiation, progression and treatment response, alternative HCC models are desirable.

Quantum dot/antibody conjugates for in vivo cytometric imaging in mice.

Multiplexed, phenotypic, intravital cytometric imaging requires novel fluorophore conjugates that have an appropriate size for long circulation and diffusion and show virtually no nonspecific binding to cells/serum while binding to cells of interest with high specificity. In addition, these conjugates must be stable and maintain a high quantum yield in the in vivo environments. Here, we show that this can be achieved using compact (∼15 nm in hydrodynamic diameter) and biocompatible quantum dot (QD) -Ab conjugates.

Differential effects of sorafenib on liver versus tumor fibrosis mediated by stromal-derived factor 1 alpha/C-X-C receptor type 4 axis and myeloid differentiation antigen-positive myeloid cell infiltration in mice.

Unlabelled: Sorafenib--a broad kinase inhibitor--is a standard therapy for advanced hepatocellular carcinoma (HCC) and has been shown to exert antifibrotic effects in liver cirrhosis, a precursor of HCC. However, the effects of sorafenib on tumor desmoplasia--and its consequences on treatment resistance--remain unknown. We demonstrate that sorafenib has differential effects on tumor fibrosis versus liver fibrosis in orthotopic models of HCC in mice.

Targeting placental growth factor/neuropilin 1 pathway inhibits growth and spread of medulloblastoma.

Medulloblastoma is the most common pediatric malignant brain tumor. Although current therapies improve survival, these regimens are highly toxic and are associated with significant morbidity. Here, we report that placental growth factor (PlGF) is expressed in the majority of medulloblastomas, independent of their subtype.

An isolated tumor perfusion model in mice.

The role of stromal cells in the tumor microenvironment has been extensively characterized. We and others have shown that stromal cells may participate in several steps of the metastatic cascade. This protocol describes an isolated tumor perfusion model that enables studies of cancer and stromal cell shedding.

BIM expression in treatment-naive cancers predicts responsiveness to kinase inhibitors.

Cancers with specific genetic mutations are susceptible to selective kinase inhibitors. However, there is a wide spectrum of benefit among cancers harboring the same sensitizing genetic mutations. Herein, we measured apoptotic rates among cell lines sharing the same driver oncogene following treatment with the corresponding kinase inhibitor.

Differential gene expression in metastasizing cells shed from kidney tumors.

We developed a novel orthotopic mouse tumor model of renal cell carcinoma to collect and characterize cells spontaneously shed from SN12C (renal cell carcinoma) and SN12L1 (high metastatic variant of SN12C) tumors grown in kidneys of severe combined immunodeficient mice. Viability of the shed cell population was greater for SN12L1 tumors (25%) compared with SN12C tumors (11%, P < 0.05).