Petrus R. de Jong

A gp130-Src-YAP module links inflammation to epithelial regeneration

Inflammation promotes regeneration of injured tissues through poorly understood mechanisms, some of which involve interleukin (IL)-6 family members, the expression of which is elevated in many diseases including inflammatory bowel diseases and colorectal cancer. Here we show in mice and human cells that gp130, a co-receptor for IL-6 cytokines, triggers activation of YAP and Notch, transcriptional regulators that control tissue growth and regeneration, independently of the gp130 effector STAT3. Through YAP and Notch, intestinal gp130 signalling stimulates epithelial cell proliferation, causes aberrant differentiation and confers resistance to mucosal erosion. gp130 associates with the related tyrosine kinases Src and Yes, which are activated on receptor engagement to phosphorylate YAP and induce its stabilization and nuclear translocation. This signalling module is strongly activated upon mucosal injury to promote healing and maintain barrier function.

The ion channel TRPV1 regulates the activation and proinflammatory properties of CD4+ T cells

TRPV1 is a Ca2+-permeable channel studied mostly as a pain receptor in sensory neurons. However, its role in other cell types is poorly understood. Here we found that TRPV1 was functionally expressed in CD4+ T cells, where it acted as a non–store-operated Ca2+ channel and contributed to T cell antigen receptor (TCR)-induced Ca2+ influx, TCR signaling and T cell activation. In models of T cell–mediated colitis, TRPV1 promoted colitogenic T cell responses and intestinal inflammation. Furthermore, genetic and pharmacological inhibition of TRPV1 in human CD4+ T cells recapitulated the phenotype of mouse Trpv1−/− CD4+ T cells. Our findings suggest that inhibition of TRPV1 could represent a new therapeutic strategy for restraining proinflammatory T cell responses.

Ion channel TRPV1-dependent activation of PTP1B suppresses EGFR-associated intestinal tumorigenesis

The intestinal epithelium has a high rate of turnover, and dysregulation of pathways that regulate regeneration can lead to tumor development; however, the negative regulators of oncogenic events in the intestinal epithelium are not fully understood. Here we identified a feedback loop between the epidermal growth factor receptor (EGFR), a known mediator of proliferation, and the transient receptor potential cation channel, subfamily V, member 1 (TRPV1), in intestinal epithelial cells (IECs). We found that TRPV1 was expressed by IECs and was intrinsically activated upon EGFR stimulation. Subsequently, TRPV1 activation inhibited EGFR-induced epithelial cell proliferation via activation of Ca2+/calpain and resulting activation of protein tyrosine phosphatase 1B (PTP1B). In a murine model of multiple intestinal neoplasia (Apc(Min/+) mice), TRPV1 deficiency increased adenoma formation, and treatment of these animals with an EGFR kinase inhibitor reversed protumorigenic phenotypes, supporting a functional association between TRPV1 and EGFR signaling in IECs. Administration of a TRPV1 agonist suppressed intestinal tumorigenesis in Apc(Min/+) mice, similar to--as well as in conjunction with--a cyclooxygenase-2 (COX-2) inhibitor, which suggests that targeting both TRPV1 and COX-2 has potential as a therapeutic approach for tumor prevention. Our findings implicate TRPV1 as a regulator of growth factor signaling in the intestinal epithelium through activation of PTP1B and subsequent suppression of intestinal tumorigenesis.

ERK5 signalling rescues intestinal epithelial turnover and tumour cell proliferation upon ERK1/2 abrogation.

The ERK1/2 MAPK signalling module integrates extracellular cues that induce proliferation and differentiation of epithelial lineages, and is an established oncogenic driver, particularly in the intestine. However, the interrelation of the ERK1/2 module relative to other signalling pathways in intestinal epithelial cells and colorectal cancer (CRC) is unclear. Here we show that loss of Erk1/2 in intestinal epithelial cells results in defects in nutrient absorption, epithelial cell migration and secretory cell differentiation. However, intestinal epithelial cell proliferation is not impeded, implying compensatory mechanisms. Genetic deletion of Erk1/2 or pharmacological targeting of MEK1/2 results in supraphysiological activity of the ERK5 pathway. Furthermore, targeting both pathways causes a more effective suppression of cell proliferation in murine intestinal organoids and human CRC lines. These results suggest that ERK5 provides a common bypass route in intestinal epithelial cells, which rescues cell proliferation upon abrogation of ERK1/2 signalling, with therapeutic implications in CRC.

The TRPA1 ion channel is expressed in CD4+ T cells and restrains T-cell-mediated colitis through inhibition of TRPV1

Objective Transient receptor potential ankyrin-1 (TRPA1) and transient receptor potential vanilloid-1 (TRPV1) are calcium (Ca2+)-permeable ion channels mostly known as pain receptors in sensory neurons. However, growing evidence suggests their crucial involvement in the pathogenesis of IBD. We explored the possible contribution of TRPA1 and TRPV1 to T-cell-mediated colitis. Design We evaluated the role of Trpa1 gene deletion in two models of experimental colitis (ie, interleukin-10 knockout and T-cell-adoptive transfer models). We performed electrophysiological and Ca2+ imaging studies to analyse TRPA1 and TRPV1 functions in CD4+ T cells. We used genetic and pharmacological approaches to evaluate TRPV1 contribution to the phenotype of Trpa1−/− CD4+ T cells. We also analysed TRPA1 and TRPV1 gene expression and TRPA1+TRPV1+ T cell infiltration in colonic biopsies from patients with IBD. Results We identified a protective role for TRPA1 in T-cell-mediated colitis. We demonstrated the functional expression of TRPA1 on the plasma membrane of CD4+ T cells and identified that Trpa1−/− CD4+ T cells have increased T-cell receptor-induced Ca2+ influx, activation profile and differentiation into Th1-effector cells. This phenotype was abrogated upon genetic deletion or pharmacological inhibition of the TRPV1 channel in mouse and human CD4+ T cells. Finally, we found differential regulation of TRPA1 and TRPV1 gene expression as well as increased infiltration of TRPA1+TRPV1+ T cells in the colon of patients with IBD. Conclusions Our study indicates that TRPA1 inhibits TRPV1 channel activity in CD4+ T cells, and consequently restrains CD4+ T-cell activation and colitogenic responses. These findings may therefore have therapeutic implications for human IBD.

YAP-IL-6ST autoregulatory loop activated on APC loss controls colonic tumorigenesis.

Significance Current therapy for advanced colorectal cancer (CRC) is unsatisfactory and CRC remains a major cause of cancer-related deaths. Thus, novel and ubiquitously acting oncogenic mediators that are amenable to pharmacological targeting need to be identified. We found that loss of adenomatous polyposis coli (APC), which is mutated in the majority of human CRC, results in up-regulation of the signaling protein IL-6ST/gp130. This results in activation of Src family kinases (SFKs), YAP, Notch, and STAT3, which are simultaneously activated in 64% of human CRC. In addition to better explaining how APC loss initiates colorectal tumorigenesis, we show that combined treatment with SFK and JAK inhibitors results in regression of established colorectal tumors in mice. Loss of tumor suppressor adenomatous polyposis coli (APC) activates β-catenin to initiate colorectal tumorigenesis. However, β-catenin (CTNNB1) activating mutations rarely occur in human colorectal cancer (CRC). We found that APC loss also results in up-regulation of IL-6 signal transducer (IL-6ST/gp130), thereby activating Src family kinases (SFKs), YAP, and STAT3, which are simultaneously up-regulated in the majority of human CRC. Although, initial YAP activation, which stimulates IL6ST gene transcription, may be caused by reduced serine phosphorylation, sustained YAP activation depends on tyrosine phosphorylation by SFKs, whose inhibition, along with STAT3-activating JAK kinases, causes regression of established colorectal tumors. These results explain why APC loss is a more potent initiating event than the mere activation of CTNNB1.

Neuronal TRPV1 activation regulates alveolar bone resorption by suppressing osteoclastogenesis via CGRP

The transient receptor potential vanilloid 1 (TRPV1) channel is abundantly expressed in peripheral sensory neurons where it acts as an important polymodal cellular sensor for heat, acidic pH, capsaicin, and other noxious stimuli. The oral cavity is densely innervated by afferent sensory neurons and is a highly specialized organ that protects against infections as well as physical, chemical, and thermal stresses in its capacity as the first part of the digestive system. While the function of TRPV1 in sensory neurons has been intensively studied in other organs, its physiological role in periodontal tissues is unclear. In this study we found that Trpv1−/− mice developed severe bone loss in an experimental model of periodontitis. Chemical ablation of TRPV1-expressing sensory neurons recapitulated the phenotype of Trpv1−/− mice, suggesting a functional link between neuronal TRPV1 signaling and periodontal bone loss. TRPV1 activation in gingival nerves induced production of the neuropeptide, calcitonin gene-related peptide (CGRP), and CGRP treatment inhibited osteoclastogenesis in vitro. Oral administration of the TRPV1 agonist, capsaicin, suppressed ligature-induced bone loss in mice with fewer tartrate-resistant acid phosphatase (TRAP)-positive cells in alveolar bone. These results suggest that neuronal TRPV1 signaling in periodontal tissue is crucial for the regulation of osteoclastogenesis via the neuropeptide CGRP.

Novel immune function for the TRPV1 channel in T lymphocytes

Novel immune function for the TRPV1 channel in T lymphocytes Samuel Bertin, Petrus Rudolf de Jong, Wilfred A Jefferies & Eyal Raz a Department of Medicine, UCSD; La Jolla, CA USA b Sanford-Burnham Medical Research Institute (SBMRI); La Jolla, CA USA c Michael Smith Laboratories, Center for Blood Research; The Brain Research Center; Department of Medical Genetics: Department of Microbiology and Immunology and Department of Zoology; University of British Columbia; Vancouver, Canada Accepted author version posted online: 21 Dec 2014.Published online: 23 Jan 2015.

STAT3: An Anti-Invasive Factor in Colorectal Cancer?

Signal Transducer and Activator of Transcription 3 (STAT3) is activated in a majority of cancers, and promotes tumorigenesis and even metastasis through transcriptional activation of its target genes. Recently, we discovered that STAT3 suppresses epithelial-to-mesenchymal transition (EMT) and thus metastasis in a mouse model of colorectal cancer (CRC), while it did not affect the overall tumor burden. Furthermore, we found that STAT3 in intestinal epithelial cells (IEC) suppresses EMT by regulating stability of an EMT inducer, SNAI-1 (Snail-1). Here, STAT3 functions as an adaptor rather than a transcription factor in the post-translational modification of SNAI-1. In this review, we discuss the unexpected and contradictory role of STAT3 in metastasis of CRC and its clinical implications.

Abstract 2967: Pancreatic cancer cell growth requires lipids released by tumor-induced stroma autophagy

Pancreatic ductal adenocarcinoma (PDAC) is non-resectable in the majority of patients and highly resistant to chemotherapy, resulting in a poor survival. The tumor microenvironment and hypoxia are important modifiers of cancer progression in PDAC. Understanding the metabolic vulnerabilities of PDAC in the harsh tumor microenvironment may lead to novel therapeutic approaches with improved clinical efficacy. First, we found that PDAC cells showed beneficial effects of co-cultured stroma cells, but only under lipid-free serum conditions. To study the metabolic crosstalk between cancer cells and stroma in more detail, we performed an untargeted metabolomic screen of PDAC cells and fibroblasts co-cultured in normoxia and hypoxia, and performed RNA-seq profiling in parallel. We found that stromal cells are metabolically more responsive to co-culture than cancer cells. PDAC cells induce catabolic carbohydrate and protein metabolism in stromal cells, particularly in hypoxia. In contrast, 13C-based metabolic flux assays demonstrated that stromal cells display enhanced anabolic lipid metabolism in co-culture with PDAC cells. Furthermore, de novo synthesized 13C-labeled fatty acids in stromal cells were taken up by PDAC cells. In particular, PDAC cells showed extensive scavenging of lysophospholipids (lyso-PLs) from the culture medium, which was increased in co-culture under hypoxic conditions. These data were confirmed by analyzing portal vein plasma samples isolated from pancreatic cancer patients before and after surgery. In addition, we found metabolites and expression levels of metabolic enzymes from the glycerophospholipid pathway to be enriched in PDAC cells in co-culture and hypoxia. By using fibroblasts, human pancreatic stellate cells and patient-derived cancer-associated fibroblasts (CAFs), we demonstrate direct transfer of lyso-PLs from stromal to PDAC cells via lipid droplets. The transfer of lyso-PLs was abrogated by pharmacological inhibitors of autophagy, or by siRNA-mediated knockdown of autophagy genes in stromal and tumor cells. These data suggest that PDAC cells cause stroma cells to undergo autophagy, and reprogram stroma metabolism to obtain complex lipid species for their metabolic needs in the lipid-starved tumor microenvironment. Citation Format: Petrus R. De Jong, Sean-Luc Shanahan, Morgan A. Brand, Alejandro D. Campos, Anagha Srirangam, Nikolas Marino, Claudia P. Miller, Olga Zagnitko, Adam D. Richardson, David A. Scott, Brian P. James, Andrew P. Hodges, Ally Perlina, Alexey M. Eroshin, Randall French, Malene Hansen, Sally A. Litherland, Andrew M. Lowy, J. Pablo Arnoletti, Garth Powis. Pancreatic cancer cell growth requires lipids released by tumor-induced stroma autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2967. doi:10.1158/1538-7445.AM2017-2967