Probes for INS

Cancer-associated fibroblasts (CAFs) play important roles in cancer progression through their complex interactions with cancer cells. The secreted bone morphogenetic protein antagonist, gremlin1 (GREM1) is expressed by the CAFs of basal cell carcinomas (BCCs), and promotes the growth of cancer cells. In this study, we investigated the expression of GREM1 mRNAs in various benign and malignant skin tumors, including various BCC subtypes. Analysis by RNA in situ hybridization (ISH) revealed that fibroblasts in the scar tissue expressed GREM1 and α-smooth muscle actin (α-SMA), whereas resident fibroblasts in the dermis of the normal skin did not express GREM1. Real-time polymerase chain reaction analysis showed significantly higher GREM1 expression in skin cancers and pilomatricomas (PMCs) than in other benign skin tumors. Tissue microarrays analyzed by RNA ISH for GREM1 expression also demonstrated that 23% of BCCs, 42% of squamous cell carcinomas, 20% of melanomas, and 90% of PMCs were positive for GREM1 expression, whereas trichoepitheliomas, eccrine poromas, hidradenomas, and spiradenomas were negative for GREM1 expression. Most BCCs that were GREM1 expression positive were of desmoplastic or mixed subtypes, and GREM1 expression was localized to activated myofibroblasts at the tumoral-stromal interface. Interestingly, most PMCs harbored GREM1-expressing fibroblasts, probably because of the inflammatory responses caused by foreign body reactions to keratin. Additionally, in BCCs, stromal GREM1 expression had a strong correlation with CD10 expression. In conclusion, GREM1 is frequently expressed by myofibroblasts in scars or in the stroma of basal cell carcinomas, suggesting that GREM1 expression can be a marker for activated myofibroblasts in the cancer stroma or in scar tissue.

Cancer associated fibroblasts (CAFs) are the dominant cell population in the cancer stroma. Gremlin 1 (GREM1), an antagonist of the bone morphogenetic protein pathway, is expressed by CAFs in a variety of human cancers. However, its biological significance for cancer patients is largely unknown. We applied RNA in situ hybridization (ISH) to evaluate the prognostic value of stromal GREM1 expression in a large cohort of 670 colorectal cancers (CRCs). Overall GREM1 expression in CRCs was lower than that of the matched normal mucosa, and GREM1 expression had a strong positive correlation with BMI1 and inverse correlations with EPHB2 and OLFM4. RNA ISH localized the GREM expression to smooth muscle cells of the muscularis mucosa, fibroblasts around crypt bases and in the submucosal space of a normal colon. In various colon polyps, epithelial GREM1 expression was exclusively observed in traditional serrated adenomas. In total, 44% of CRCs were positive for stromal GREM1, which was associated with decreased lymphovascular invasion, a lower cancer stage, and nuclear β-catenin staining. Stromal GREM1 was significantly associated with improved recurrence-free and overall survival, although it was not found to be an independent prognostic marker in multivariate analyses. In addition, for locally advanced stage II and III CRCs, it was associated with better, stage-independent clinical outcomes. In summary, CRCs are frequently accompanied by GERM1-expressing fibroblasts, which are closely associated with low lymphovascular invasion and a better prognosis, suggesting stromal GREM1 as a potential biomarker and possible candidate for targeted therapy in the treatment of CRCs.

Abstract

BACKGROUND/AIMS:

Murine nephrotoxic nephritis (NTN) is a well-established model resembling chronic kidney disease. Investigating gene expression patterns separately in the glomerular and cortical tubulointerstitial structure could provide new knowledge about structure-specific changes in expression of genes in the NTN model.

METHODS:

Glomerular, cortical tubulointerstitial and whole kidney tissues from mice subjected to nephrotoxic serum (NTS) or phosphate buffered saline (PBS) were collected on day 7, 21 and 42 using laser microdissection (LMD). Total RNA was extracted and subjected to nCounter NanoString. Histology, immunohistochemistry, in situ hybridization and/or quantitative real time PCR (qRT PCR) were performed to confirm regulation of selected genes.

RESULTS:

LMD provided detailed information about genes that were regulated differently between structures over time. Some of the fibrotic and inflammatory genes (Col1a1, Col3a1 and Ccl2) were upregulated in both structures, whereas other genes such as Spp1 and Grem1 were differentially regulated suggesting spatial pathogenic mechanisms in the kidney. Downregulation of cortical tubulointerstitium genes involved in iron metabolism was detected along with iron accumulation.

CONCLUSION:

This study demonstrates several regulated genes in pathways important for the pathogenesis of the NTN model and that LMD identifies structure-specific changes in gene expression during disease development. Furthermore, this study shows the benefits of isolating glomeruli and cortical tubulointerstitium in order to identify gene regulation.

Grem1, an antagonist of bone morphogenetic proteins, plays a key role in embryogenesis. A highly specific temporospatial gradient of Grem1 and BMP signalling is critical to normal lung, kidney and limb development. Grem1 levels are increased in renal fibrotic conditions including acute kidney injury, diabetic nephropathy, chronic allograft nephropathy and immune glomerulonephritis. A small number of grem1-/- whole body knockout mice on a mixed genetic background (8 %) are viable, with a single, enlarged left kidney and grossly normal histology. Grem1-/- mice displayed mild renal dysfunction at 4 wk, which recovered by 16 wk. Tubular epithelial specific targeted deletion of Grem1 (Grem1-TEC-/-) mice displayed a milder response in both the acute injury and recovery phase of the folic acid model. Grem1-TEC-/- mice had smaller increases in indices of kidney damage compared to wild-type. In the recovery phase of the folic acid model, associated with renal fibrosis, Grem1-TEC-/- mice displayed reduced histological damage and an attenuated fibrotic gene response compared to wild-type controls. Together, these data demonstrated that Grem1 expression in the tubular epithelial compartment plays a significant role in the fibrotic response to renal injury in vivo.

Malignant glioma (MG), the most common primary brain tumor in adults, is extremely aggressive and uniformly fatal. Several treatment strategies have shown significant preclinical promise in murine models of glioma; however, none have produced meaningful clinicalresponses in human patients. We hypothesize that introduction of an additional preclinical animal model better approximating the complexity of human MG, particularly in interactions with host immune responses, will bridge the existing gap between these two stages of testing. Here, we characterize the immunologic landscape and gene expression profiles of spontaneous canine glioma and evaluate its potential for serving as such a translational model. RNA in situ hybridization, flowcytometry, and RNA sequencing were used to evaluate immune cell presence and gene expression in healthy and glioma-bearing canines. Similar to human MGs, canine gliomas demonstrated increased intratumoral immune cell infiltration (CD4+, CD8+ and CD4+Foxp3+ T cells). The peripheral blood of glioma-bearing dogs also contained a relatively greater proportion of CD4+Foxp3+ regulatory T cells and plasmacytoid dendritic cells. Tumors were strongly positive for PD-L1 expression and glioma-bearing animals also possessed a greater proportion of immune cells expressing the immune checkpoint receptors CTLA-4 and PD-1. Analysis of differentially expressed genes in our canine populations revealed several genetic changes paralleling those known to occur in human disease. Naturally occurring canine glioma has many characteristics closely resembling human disease, particularly with respect to genetic dysregulation and host immune responses to tumors, supporting its use as a translational model in the preclinical testing of prospective anti-glioma therapies proven successful in murine studies.

Prostate cancer (PCa) does not appear to respond to immune checkpoint therapies where T cell infiltration may be a key limiting factor. Here we report evidence that ablating the growth regulatory kinase Erk5 can increase T cell infiltration in an established Pten-deficient mouse model of human PCa. Mice that were doubly mutant in prostate tissue for Pten and Erk5 (prostate DKO) exhibited a markedly increased median survival with reduced tumor size and proliferation compared to control Pten-mutant mice, the latter of which exhibited increased Erk5 mRNA expression. A comparative transcriptomic analysis revealed upregulation in prostate DKO mice of the chemokines Ccl5 and Cxcl10, two potent chemoattractants for T lymphocytes. Consistent with this effect, we observed a relative increase in a predominantly CD4+ T cell infiltrate in the prostate epithelial and stroma of tumors from DKO mice. Collectively, our results offer a preclinical proof of concept for ERK5 as a target to enhance T cell infiltrates in prostate cancer, with possible implications for leveraging immune therapy in this disease.