The role of stress signals in regulating gastric cancer initiation and progression is not quite clear. It is known that stress signals modulate multiple processes such as immune function, cell migration and angiogenesis. However, few studies have investigated the mechanisms of how stress signals contribute to gastric cancer angiogenesis. Here, we used β2-adrenergic receptor (β2-AR) agonist isoprenaline to imitate a stress signal and demonstrated the molecular mechanism underlying stress’s influence on tumor angiogenesis. We found that isoprenaline stimulated vascular endothelial growth factor (VEGF) secretion in gastric cancer cells and plexin-A1 expression was induced by human recombinant VEGF165 in both gastric cancer cells and vascular endothelial cells. Furthermore, interfere with plexin-A1 expression in gastric cancer cells influence HUVEC tube formation, migration and tumor growth in vivo. These findings suggest that isoprenaline stimulate VGEF secretion and subsequently up-regulate the expression of plexin-A1 and VEGFR2 in gastric cancer cells, which form a positive impetus to promote tumor angiogenesis. This study reveals a novel molecular mechanism that a stress signal like isoprenaline may enhance angiogenesis via activating plexin-A1/VEGFR2 signaling pathway in gastric cancer, which may be a potential target in development of an anti-angiogenic therapy for gastric cancer.

Objective: We investigated the clinical significance of preoperative pan-immune-inflammation value (PIV) in patients with colorectal cancer (CRC).Methods: In this retrospective study, 366 cases who underwent surgery for CRC were enrolled. Their clinical data were collected. PIV was calculated with the formula PIV = [neutrophil count (10⁹/L)× platelet count (10⁹/L) × monocyte count (10⁹/L) /lymphocyte count (10⁹/L). Patients were divided into high PIV (> median PIV) and low PIV (< median PIV) groups. The relationship between PIV and clinicopathological features of CRC was investigated. Receiver operating characteristic (ROC) curve was plotted to indicate the value of immune-inflammatory biomarkers (IIBs) in predicting the TNM stage of CRC, and the area under the curve (AUC) was calculated to evaluate the actual clinical value of IIBs. AUC > 0.5 and closer to 1 indicated the better predictive efficacy. The influencing factors of PIV in CRC were analyzed.Results: We found that PIV was positively correlated with tumor size (r = 0.300, p < 0.05), carcinoembryonic antigen (CEA) (r = 0.214, p < 0.05) and carbohydrate antigen 125 (CA-125) (r = 0.249, p < 0.05), but negatively correlated with albumin (Alb) (r = −0.242, p < 0.05). PIV was significantly different in patients with different tumor locations (left or right), surgical methods (laparotomy versus laparoscopic surgery) (p < 0.05), and patients with different pathological T stages, N-stage and TNM stages (p < 0.05). ROC curve analysis of IIBs showed the AUC of PIV was greater than other markers when combined with CEA or carbohydrate antigen 19–9 (CA19–9). Multivariate regression analysis identified T stage, CEA, Alb, and tumor size as the independent influential factors of PIV in CRC.Conclusion: PIV is associated with the tumor stage in patients with CRC, which may be useful in preoperative assessment of CRC.

With the medical model shifting from a single biomedical model to a biopsychological-social model, the impact of psychosocial factors on cancer patients has attracted attention. Studies have shown that chronic stress caused by long-term psychological stress, such as anxiety and depression, can promote the malignant progression of tumors by acting on β2-adrenergic receptor (β2-AR). β2-AR can promote tumor migration by activating epithelial-mesenchymal transition (EMT). However, the underlying mechanisms in the regulation of EMT by β2-AR are still unclear. In this study, we established a chronic stress model by treating MGC-803 and SGC-7901 human gastric cancer cells with isoproterenol (ISO), a β2-AR agonist. EMT in the two gastric cancer cell lines was enhanced after ISO treatment. Thereafter, we found that the interaction between β2-AR and PlexinA1 was involved in the process by which chronic stress affects EMT in both MGC-803 and SGC-7901 cells. Moreover, the activation of β2-AR by ISO increased the expression of PlexinA1, activated JAK-STAT3 signaling and further promoted EMT in human gastric cancer cells. Importantly, the knockdown of PlexinA1 by small hairpin RNAs inhibited JAK-STAT3 signaling and abolished the EMT induced by β2-AR. In conclusion, PlexinA1 was an important downstream target of β2-AR, through which β2-AR promoted EMT in human gastric cancer cells by activating JAK-STAT3 signaling.

It is known that chronic stress modulates multiple processes in a complex microenvironment, such as angiogenesis and immune function. However, the role of chronic stress inducing tumor angiogenesis and how it contributes to tumor progression are not quite clear. The following study assess psychological state from numerous ambulatory cancer cases (n=332), and chronic stress-related hormone levels were further measured. Here, we show that chronic stress not only causes behavioral changes in human, most importantly attributed to an elevated level of stress-related hormones. To address this, isoprenaline, the agonist of β2-adrenergic receptor (β2-AR), was utilized for simulating chronic stress and demonstrating the mechanism of stress in tumor angiogenesis at molecular level both in vivo and in vitro. As suggested by this study, isoprenaline promote VEGF autocrine of HUVECs, which can induce plexinA1 and VEGFR2 expression. Moreover, we show that isoprenaline promoted the expression of p-JAK2 and p-STAT3 in vitro. The results reveal that, isoprenaline enhances the autocrine of VEGF in HUVECs and up-regulating plexinA1 and VEGFR2 levels, thus activating the phosphorylation of JAK2-STAT3 pathway, the two essential parts during angiogenesis. The present work indicates that, the mechanism of chronic stress in enhancing angiogenesis is probably achieved through activating the plexinA1/VEGFR2-JAK2-STAT3 signal transduction pathway within HUVECs, and this is probably a candidate target for developing a strategy against angiogenesis in cancer.

Chronic stress induced by long-term anxiety and depression can promote the malignant progression of gastric cancer. β2-adrenergic receptor (β2-AR) is a critical mediator for chronic stress-induced multiple processes of tumor cells. However, the function of chronic stress in gastric cancer and its potential mechanisms in vivo and in vitro, especially at the cellular level, remain unknown. Here, we provide further evidence that chronic stress affected behavior and hypothalamus pituitary adrenal axis related hormone levels in mice. Furthermore, immunofluorescence showed that emotion affected the expression of epithelial-mesenchymal transition (EMT) markers in patients' tissues. To address this, salbutamol, a specific agonist of β2-AR, was utilized for simulating chronic stress and demonstrating the mechanism of stress in tumor progression at the molecular level both in vivo and in vitro. Salbutamol significantly induced EMT, migration and invasion via ERK (Extracellular-signal-regulated kinase) phosphorylation, and the effects were reversed by the β2-AR antagonist ICI-118,551. The promoting effects of salbutamol on EMT, migration and invasion were inhibited by phosphorylation inhibitor of ERK PD98059 in vitro. Analysis of xenograft models revealed that salbutamol significantly promoted tumor growth and adrenal volume, while ICI-118,551 inhibited these effects. In addition, salbutamol increased the expression of mesenchymal marker N-cadherin and decreased epithelial marker E-cadherin in transplanted tumor tissue. In conclusion, salbutamol simulates a chronic stress model, which promotes tumorigenesis of gastric cancer cells through β2-AR/ERK/EMT pathway.