A new function for MAP4K4 inhibitors during platelet aggregation and platelet-mediated clot retraction

Roles of Integrin in Cardiovascular Diseases: From Basic Research to Clinical Implications

Cardiovascular diseases (CVDs) pose a significant global health threat due to their complex pathogenesis and high incidence, imposing a substantial burden on global healthcare systems. Integrins, a group of heterodimers consisting of α and β subunits that are located on the cell membrane, have emerged as key players in mediating the occurrence and progression of CVDs by regulating the physiological activities of endothelial cells, vascular smooth muscle cells, platelets, fibroblasts, cardiomyocytes, and various immune cells. The crucial role of integrins in the progression of CVDs has valuable implications for targeted therapies. In this context, the development and application of various integrin antibodies and antagonists have been explored for antiplatelet therapy and anti-inflammatory-mediated tissue damage. Additionally, the rise of nanomedicine has enhanced the specificity and bioavailability of precision therapy targeting integrins. Nevertheless, the complexity of the pathogenesis of CVDs presents tremendous challenges for monoclonal targeted treatment. This paper reviews the mechanisms of integrins in the development of atherosclerosis, cardiac fibrosis, hypertension, and arrhythmias, which may pave the way for future innovations in the diagnosis and treatment of CVDs.

Overcoming radioresistance of breast cancer cells with MAP4K4 inhibitors

Mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) has recently emerged as a promising therapeutic target in cancer. In this study, we explored the biological function of MAP4K4 in radioresistant breast cancer cells using two MAP4K4 inhibitors, namely PF06260933 and GNE-495. Radioresistant SR and MR cells were established by exposing SK-BR-3 and MCF-7 breast cancer cells to 48-70 Gy of radiation delivered at 4-5 Gy twice a week over 10 months. Surprisingly, although radioresistant cells were derived from two different subtypes of breast cancer cell lines, MAP4K4 was significantly elevated regardless of subtype. Inhibition of MAP4K4 with PF06260933 or GNE-495 selectively targeted radioresistant cells and improved the response to irradiation. Furthermore, MAP4K4 inhibitors induced apoptosis through the accumulation of DNA damage by inhibiting DNA repair systems in radioresistant cells. Notably, Inhibition of MAP4K4 suppressed the expressions of ACSL4, suggesting that MAP4K4 functioned as an upstream effector of ACSL4. This study is the first to report that MAP4K4 plays a crucial role in mediating the radioresistance of breast cancer by acting upstream of ACSL4 to enhance DNA damage response and inhibit apoptosis. We hope that our findings provide a basis for the development of new drugs targeting MAP4K4 to overcome radioresistance.

Daidzein Inhibits Human Platelet Activation by Downregulating Thromboxane A2 Production and Granule Release, Regardless of COX-1 Activity

Platelets play crucial roles in cardiovascular diseases (CVDs) by regulating hemostasis and blood coagulation at sites of blood vessel damage. Accumulating evidence indicates daidzein inhibits platelet activation, but the mechanism involved has not been elucidated. Thus, in this study, we investigated the mechanism responsible for the inhibition of collagen-induced platelet aggregation by daidzein. We found that in collagen-induced platelets, daidzein suppressed the production of thromboxane A2 (TXA2), a molecule involved in platelet activation and aggregation, by inhibiting the cytosolic phospholipase A2 (cPLA2) signaling pathway. However, daidzein did not affect cyclooxygenase-1 (COX-1). Furthermore, daidzein attenuated the PI3K/PDK1/Akt/GSK3αβ and MAPK (p38, ERK) signaling pathways, increased the phosphorylation of inositol trisphosphate receptor1 (IP3R1) and vasodilator-stimulated phosphoprotein (VASP), and increased the level of cyclic adenosine monophosphate (cAMP). These results suggest that daidzein inhibits granule release (ATP, serotonin, P-selectin), integrin αIIbβ3 activation, and clot retraction. Taken together, our study demonstrates that daidzein inhibits collagen-induced platelet aggregation and suggests that daidzein has therapeutic potential for the treatment of platelet aggregation-related diseases such as atherosclerosis and thrombosis.

Systemic Review of Clot Retraction Modulators

Through a process termed clot retraction, platelets cause thrombi to shrink and become more stable. After platelets are activated via inside-out signaling, glycoprotein αIIbβIII binds to fibrinogen and initiates a cascade of intracellular signaling that ends in actin remodeling, which causes the platelet to change its shape. Clot retraction is also important for wound healing. Although the detailed molecular biology of clot retraction is only partially understood, various substances and physiological conditions modulate clot retraction. In this review, we describe some of the current literature pertaining to clot retraction modulators. In addition, we discuss compounds from Cudrania trucuspidata, Arctium lappa, and Panax ginseng that diminish clot retraction and have numerous other health benefits. Caffeic acid and diindolylmethane, both common in plants and vegetables, likewise reduce clot retraction, as do all-trans retinoic acid (a vitamin A derivative), two MAP4K inhibitors, and the chemotherapeutic drug Dasatinib. Conversely, the endogenous anticoagulant Protein S (PS) and the matricellular protein secreted modular calcium-binding protein 1 (SMOC1) both enhance clot retraction. Most studies aiming to identify mechanisms of clot retraction modulators have focused on the increased phosphorylation of vasodilator-stimulated phosphoprotein and inositol 1,4,5-triphosphate receptor I and the decreased phosphorylation of various phospholipases (e.g., phospholipase A2 (PLA2) and phosphatidylinositol-specific phospholipase Cγ2 (PLCγ2), c-Jun N-terminal kinase, and (PI3Ks). One study focused on the decreased phosphorylation of Sarcoma Family Kinases (SFK), and others have focused on increased cAMP levels and the downregulation of inflammatory markers such as thromboxanes, including thromboxane A2 (TXA2) and thromboxane B2 (TXB2); prostaglandin A2 (PGE2); reactive oxygen species (ROS); and cyclooxygenase (COX) enzyme activity. Additionally, pregnancy, fibrinolysis, and the autoimmune condition systemic lupus erythematosus all seem to affect, or at least have some relation with, clot retraction. All the clot retraction modulators need in-depth study to explain these effects.

FLI1 and FRA1 transcription factors drive the transcriptional regulatory networks characterizing muscle invasive bladder cancer

Bladder cancer is mostly present in the form of urothelium carcinoma, causing over 150,000 deaths each year. Its histopathological classification as muscle invasive (MIBC) and non-muscle invasive (NMIBC) is the most prominent aspect, affecting the prognosis and progression of this disease. In this study, we defined the active regulatory landscape of MIBC and NMIBC cell lines using H3K27ac ChIP-seq and used an integrative approach to combine our findings with existing data. Our analysis revealed FRA1 and FLI1 as two critical transcription factors differentially regulating MIBC regulatory landscape. We show that FRA1 and FLI1 regulate the genes involved in epithelial cell migration and cell junction organization. Knock-down of FRA1 and FLI1 in MIBC revealed the downregulation of several EMT-related genes such as MAP4K4 and FLOT1. Further, ChIP-SICAP performed for FRA1 and FLI1 enabled us to infer chromatin binding partners of these transcription factors and link this information with their target genes. Finally, we show that knock-down of FRA1 and FLI1 result in significant reduction of invasion capacity of MIBC cells towards muscle microenvironment using IC-CHIP assays. Our results collectively highlight the role of these transcription factors in selection and design of targeted options for treatment of MIBC.