Activation of corticotropin-releasing factor receptor 2 inhibits the growth of human small cell lung carcinoma cells

Association between genetic variant rs2267716 of CRHR2 gene with colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and one of the main causes of death around the world. Multiple lines of evidence have suggested the role of the corticotropin-releasing hormone (CRH) family in CRC induction, including the low expression of corticotropin-releasing hormone receptor 2 (CRHR2), which is an angiogenesis inhibitor and inflammatory modulator. Previous research suggests that CRHR2 expression in colonic intestinal cells can regulate migration, proliferation and apoptosis through the modulation of several pathways. The aim of this study was to analyze the association of the rs10250835, rs2267716 and rs2267717 variants of CRHR2 gene with CRC in the Mexican population in order to consider its predictive value in CRC. This cross-sectional study included a group of 187 unrelated patients with sporadic CRC and a control group of 191 healthy blood donors. DNA extraction from peripheral blood was carried out using the Miller method. Identification of the rs10250835 variant was performed using PCR-restriction fragment length polymorphism (RFLP) and the rs2267716 and rs2267717 variants using TaqMan allelic discrimination assay. The minor allele homozygous CC of the rs2267716 variant of CRHR2 showed significant difference between CRC and control group (p=0.025), as well as the GCA haplotype (p=0.007), corresponding to the rs10250835, rs2267716 and rs2267717 variants, respectively. Our results suggest that the rs2267716 variant and GCA haplotype of CRHR2 represent a risk factor for CRC development in Mexican patients.

Anabolic and Pro-metabolic Functions of CREB-CRTC in Skeletal Muscle: Advantages and Obstacles for Type 2 Diabetes and Cancer Cachexia

cAMP is one of the earliest described mediators of hormone action in response to physiologic stress that allows acute stress responses and adaptation in every tissue. The classic role of cAMP signaling in metabolic tissues is to regulate nutrient partitioning. In response to acute stress, such as epinephrine released during strenuous exercise or fasting, intramuscular cAMP liberates glucose from glycogen and fatty acids from triglycerides. In the long-term, activation of Gs-coupled GPCRs stimulates muscle growth (hypertrophy) and metabolic adaptation through multiple pathways that culminate in a net increase of protein synthesis, mitochondrial biogenesis, and improved metabolic efficiency. This review focuses on regulation, function, and transcriptional targets of CREB (cAMP response element binding protein) and CRTCs (CREB regulated transcriptional coactivators) in skeletal muscle and the potential for targeting this pathway to sustain muscle mass and metabolic function in type 2 diabetes and cancer. Although the muscle-autonomous roles of these proteins might render them excellent targets for both conditions, pharmacologic targeting must be approached with caution. Gain of CREB-CRTC function is associated with excess liver glucose output in type 2 diabetes, and growing evidence implicates CREB-CRTC activation in proliferation and invasion of different types of cancer cells. We conclude that deeper investigation to identify skeletal muscle specific regulatory mechanisms that govern CREB-CRTC transcriptional activity is needed to safely take advantage of their potent effects to invigorate skeletal muscle to potentially improve health in people with type 2 diabetes and cancer.

Identification of novel enriched recurrent chimeric COL7A1-UCN2 in human laryngeal cancer samples using deep sequencing

BACKGROUND

As hybrid RNAs, transcription-induced chimeras (TICs) may have tumor-promoting properties, and some specific chimeras have become important diagnostic markers and therapeutic targets for cancer.

METHODS

We examined 23 paired laryngeal cancer (LC) tissues and adjacent normal mucous membrane tissue samples (ANMMTs). Three of these pairs were used for comparative transcriptomic analysis using high-throughput sequencing. Furthermore, we used real-time polymerase chain reaction (RT-PCR) for further validation in 20 samples. The Kaplan-Meier method and Cox regression model were used for the survival analysis.

RESULTS

We identified 87 tumor-related TICs and found that COL7A1-UCN2 had the highest frequency in LC tissues (13/23; 56.5%), whereas none of the ANMMTs were positive (0/23; p < 0.0001). COL7A1-UCN2, generated via alternative splicing in LC tissue cancer cells, had disrupted coding regions, but it down-regulated the mRNA expression of COL7A1 and UCN2. Both COL7A1 and UCN2 were down-expressed in LC tissues as compared to their paired ANMMTs. The COL7A1:β-actin ratio in COL7A1-UCN2-positive LC samples was significantly lower than that in COL7A1-UCN2-negative samples (p = 0.019). Likewise, the UCN2:β-actin ratio was also decreased (p = 0.21). Furthermore, COL7A1-UCN2 positivity was significantly associated with the overall survival of LC patients (p = 0.032; HR, 13.2 [95%CI, 1.2-149.5]).

CONCLUSION

LC cells were enriched in the recurrent chimera COL7A1-UCN2, which potentially affected cancer stem cell transition, promoted epithelial-mesenchymal transition in LC, and resulted in poorer prognoses.

Corticotropin Releasing Hormone and Urocortin 3 Stimulate Vascular Endothelial Growth Factor Expression through the cAMP/CREB Pathway

Colonic epithelium is the first line of defense against various pathological offenses in the gut. Previous studies have shown that the peptides of the corticotropin-releasing hormone (CRH) family modulate vascular endothelial growth factor (VEGF)-A production in other cells. Here we sought to investigate whether CRH and urocortin (Ucn) 3 regulate VEGF-A secretion in colonocytes through CRH receptors and to elucidate the underlying mechanism of action. CRH and Ucn 3 significantly increased the expression levels of VEGF-A mRNA and protein through CRH receptor 1 and 2, respectively, in human colonic epithelial cells and primary mouse intestinal epithelial cells. Underlying mechanisms involve activation of adenylyl cyclase with subsequent increase of intracellular cAMP level and increased DNA binding activity of transcription factor CREB on VEGF-A promoter region. Finally, genetic deficiency of CREB decreased intestinal inflammation and VEGF-A expression in a dextran sodium sulfate-induced colitis model. These results show that activation of CRH receptors by CRH ligands stimulates VEGF-A expression in intestinal epithelial cells through the cAMP/CREB pathway. Since VEGF-A boosts inflammatory responses through angiogenesis, these data suggest that CREB may be a key effector of CRH and Ucn 3-dependent inflammatory angiogenesis.

Multi-facets of Corticotropin-releasing Factor in Modulating Inflammation and Angiogenesis

The family of corticotropin-releasing factor (CRF) composed of 4 ligands including CRF, urocortin (Ucn) 1, Ucn2, and Ucn3 is expressed both in the central nervous system and the periphery including the gastrointestinal tract. Two different forms of G protein coupled receptors, CRF₁ and CRF₂, differentially recognize CRF family members, mediating various biological functions. A large body of evidence suggests that the CRF family plays an important role in regulating inflammation and angiogenesis. Of particular interest is a contrasting role of the CRF family during inflammatory processes. The CRF family can exert both pro-and anti-inflammatory functions depending on the type of receptors, the tissues, and the disease phases. In addition, there has been a growing interest in a possible role of the CRF family in angiogenesis. Regulation of angiogenesis by the CRF family has been shown to modulate endogenous blood vessel formation, inflammatory neovascularization and cardiovascular function. This review outlines the effect of the CRF family and its receptors on 2 major biological events: inflammation and angiogenesis, and provides a possibility of their application for the treatment of inflammatory vascular diseases.

CRH suppressed TGFβ1-induced Epithelial-Mesenchymal Transition via induction of E-cadherin in breast cancer cells

Since its discovery in biopsies from breast cancer patients, the effect of corticotropin-releasing hormone (CRH) on carcinoma progression is still unclear. Transforming growth factorβ1 (TGFβ1) promotes Epithelial-Mesenchymal Transition (EMT) and induces Snail1 and Twist1 expressions. Loss of epithelial cadherin (E-cadherin) mainly repressed by Snail1 and Twist1, has been considered as hallmark of Epithelial-Mesenchymal Transition (EMT). Two breast cancer cell lines, MCF-7 and MDA-MB-231 were used to investigate the effect of CRH on TGFβ1-induced EMT by transwell chamber. And HEK293 cells were transiently transfected with CRHR1 or CRHR2 to explore the definite effects of CRH receptor. We reported that CRH inhibited migration of human breast cancer cells through downregulation of Snail1 and Twist1, and subsequent upregulation of E-cadherin. CRH inhibited TGFβ1-mediated migration of MCF-7 via both CRHR1 and CRHR2 while this inhibition in MDA-MB-231 was mainly via CRHR2. Ectopic re-expression of CRHR1 or CRHR2 respectively in HEK293 cells increased E-cadherin expression after CRH stimulation. Furthermore, CRH repressed expression of mesenchymal marker, N-cadherin and induced expression of Occludin, inhibiting EMT in MCF-7 & MDA-MB-231. Our results suggest that CRH may function as a tumor suppressor, at least partly by regulating TGFβ1-mediated EMT. These results may contribute to uncovering the effect of CRH in breast tumorigenesis and progression.

Urocortin 2 is associated with abdominal aortic aneurysm and mediates anti-proliferative effects on vascular smooth muscle cells via corticotrophin releasing factor receptor 2

There are no current effective drug therapies for abdominal aortic aneurysm, an important cause of death in older adults. Our study suggests that urocortin 2 participates in the disease process and may serve as a putative therapeutic target.