Studies have shown that stress such as hypoxia, chemotherapy, radiotherapy can lead to polyploidization of tumor cells, which play an important role in tumor heterogeneity and malignant phenotype. Paclitaxel (PTX) treatment promoted polyploid cancer cells (PCCs) formation, and miR-378d is sharply reduced in PCCs of esophageal squamous cell carcinomas (ESCC) cells, but miR-378d participation PCCs formation and the impact on the biological behavior of ESCC remains unclear. We analyzed the PCCs formation and biological behavior of ESCC cells in vivo and in vitro, and the related proteins regulated by miR-378d. Results showed that miR-378d expression was associated with good prognosis in ESCC patients. miR-378d inhibition promoted PCCs formation, heterogenicity, chemo-resistance, monoclonal formation, EMT, migration, invasion, stemness and metastasis of ESCC cells. miR-378d can target downregulated AKT1, and inactivating the AKT-β-catenin signaling pathway, miR-378d and AKT can also regulated RhoA expression. AKT and RhoA regulated polyploidization and depolyploidization. Therefore, miR-378d expression is a good prognostic factor of ESCC patients and regulates polyploidization and malignant phenotype of tumor cells through AKT and RhoA.

Pulmonary hypertension (PH) is a serious disorder with high morbidity and mortality rate. We analyzed the right ventricular systolic pressure (RVSP), right ventricular hypertrophy (RVH), lung histology and transcriptomes of six weeks old male rats with PH induced by: 1) hypoxia (HO), 2) administration of monocrotaline (CM) or 3) administration of monocrotaline and exposure to hypoxia (HM). The results in PH rats were compared to those in control rats (CO). After four weeks exposure, increased RVSP and RVH, pulmonary arterial wall thickening, and alteration of the lung transcriptome were observed in all PH groups. The HM group exhibited the largest alterations and also neointimal lesions and obliteration of lumen in small arteries. We found that the PH increased the expression of caveolin1, matrix metallopeptidase 2 and numerous inflammatory and cell proliferation genes. The cell-cycle, vascular smooth muscle contraction and the oxidative phosphorylation pathways, as well as their interplay were largely perturbed. Our results also suggest that the up-regulated Rhoa (ras homolog family member A) mediates its action through expression coordination with several ATPases. The upregulation of antioxidant genes and the extensive mitochondrial damage observed especially in HM group, indicate metabolic shift towards aerobic glycolysis.

Chronic inflammation, the activation of immune cells and their cross-talk with cardiomyocytes in the pathogenesis and progression of heart diseases has long been overlooked. However, with the latest research developments, it is increasingly accepted that a vicious cycle exists where cardiomyocytes release cardiocrine signaling molecules that spirals down to immune cell activation and chronic state of low‐level inflammation. For example, cardiocrine molecules released from injured or stressed cardiomyocytes can stimulate macrophages, dendritic cells, neutrophils and even T-cells, which then subsequently increase cardiac inflammation by co-stimulation and positive feedback-loops. One of the key proteins involved in stress-mediated cardiomyocyte signal transduction is a small GTPase RhoA. Importantly, the regulation of RhoA activation is critical for effective immune cell response and is being considered as one of the potential therapeutic targets in many immune-cell-mediated inflammatory diseases. In this review we provide an update on the role of RhoA at the juncture of immune cell activation, inflammation and cardiac disease.

Although the migration of hepatic stellate cells (HSCs) is important for hepatic fibrosis, the regulation of HSC migration is poorly understood. Interestingly, transforming growth factor (TGF)-β1 induces monocyte migration to sites of injury or inflammation in the early phase but inhibits cell migration in the late phase. In this study, we investigated the role of RhoA signaling in TGF-β1-induced HSC migration. We found that TGF-β1 increased the protein and mRNA levels of α-SMA and collagen type I in HSC-T6 cells. The level of RhoA-GTP in TGF-β1-stimulated cells was significantly higher than that in control cells. Moreover, cofilin phosphorylation and F-actin formation was more strongly detected in TGF-β1-stimulated cells than in control cells. Additionally, TGF-β1 induced the activation of NF-κB and the expression of extracellular matrix proteins and several cytokines in HSC-T6 cells. The active form of Rap1 (Rap1 V12) suppressed RhoA-GTP levels, whereas the dominant negative form of Rap1 (Rap1 N17) augmented RhoA-GTP levels. Therefore, we confirmed that Rap1 regulates RhoA activation in TGF-β1-stimulated HSC-T6 cells. These findings suggest that TGF-β1 regulates Rap1, resulting in RhoA suppression, NF-κB activation and F-actin formation during the migration of HSCs.