Cryptotanshinone Prevents the Binding of S6K1 to mTOR/Raptor Leading to the Suppression of mTORC1-S6K1 Signaling Activity and Neoplastic Cell Transformation

Inhibition of p70 Ribosomal S6K1 Protects the Myocardium against Ischemia/Reperfusion-Induced Necrosis through Downregulation of RIP3

BACKGROUND

Myocardial ischemia-reperfusion (I/R) injury refers to cell damage that occurs as a consequence of the restoration of blood circulation following reperfusion therapy for cardiovascular diseases, and it is a primary cause of myocardial infarction. The search for nove therapeutic targets in the context of I/R injury is currently a highly active area of research. p70 ribosomal S6 kinase (S6K1) plays an important role in I/R induced necrosis, although the specific mechanisms remain unclear.

OBJECTIVE

This study aims to explore the effects of inhibiting S6K1 on myocardial I/R injury and its potential mechanisms.

METHODS

A rat myocardial I/R model was created and treated with the S6K1-specific inhibitor PF-4708671. Hematoxylin-eosin (H&E) staining was applied to evaluate the pathological changes in cardiac tissues. 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to measure the area of myocardial infarction (MI). Left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), the maximum rate of increase in left ventricular pressure (+dp/dtmax), and the maximum rate of the decrease in left ventricular pressure (-dp/dtmax) were measured using ultrasonic echocardiography. The expression levels of cardiac troponin-1 (cTn-1), lactate dehydrogenase (LDH), creatine kinase MB (CK-MB), and aspartate aminotransferase (AST) were determined by enzyme-linked immunosorbent assay (ELISA). Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining and propidium iodide (PI) staining were used to examine the apoptosis and necrosis of myocardial tissues. The expressions of apoptotic-related proteins, and key molecules of necrosis were detected by western blot. The relationship between S6K1 and receptor-interacting protein kinase 3 (RIP3) was analyzed by immunoprecipitation.

RESULTS

Inhibition of S6K1 reduces I/R-induced myocardial tissue damage, improves myocardial function, and inhibits myocardial tissue necrosis (p < 0.05). In addition, RIP3 is a direct target of S6K1, and activation of RIP3 blocked the protective effect of the S6K1 inhibitor PF-4708671 against myocardial I/R injury (p < 0.05).

CONCLUSION

Inhibition of S6K1 protects against myocardial I/R injury by down-regulating RIP3, suggesting that targeting S6K1 may offer a novel approach for intervention in myocardial I/R injury.

Implications of cancer stem cells in diabetes and pancreatic cancer

This review provides a detailed study of pancreatic cancer (PC) and the implication of different types of cancers concerning diabetes. The combination of anti-diabetic drugs with other anti-cancer drugs and phytochemicals can help prevent and treat this disease. PC cancer stem cells (CSCs) and how they migrate and develop into malignant tumors are discussed. A detailed explanation of the different mechanisms of diabetes development, which can enhance the pancreatic CSCs' proliferation by increasing the IGF factor levels, epigenetic modifications, DNA damage, and the influence of lifestyle factors like obesity, and inflammation, has been discussed. It also explains how cancer due to diabetes is associated with high mortality rates. One of the well-known diabetic drugs, metformin, can be combined with other anti-cancer drugs and prevent the development of PC and has been taken as one of the prime focus in this review. Overall, this paper provides insight into the relationship between diabetes and PC and the methods that can be employed to diagnose this disease at an earlier stage successfully.

Molecular Mechanism of Tanshinone against Prostate Cancer

Prostate cancer (PCa) is the most common malignant tumor of the male urinary system in Europe and America. According to the data in the World Cancer Report 2020, the incidence rate of PCa ranks second in the prevalence of male malignant tumors and varies worldwide between regions and population groups. Although early PCa can achieve good therapeutic results after surgical treatment, due to advanced PCa, it can adapt and tolerate androgen castration-related drugs through a variety of mechanisms. For this reason, it is often difficult to achieve effective therapeutic results in the treatment of advanced PCa. Tanshinone is a new fat-soluble phenanthraquinone compound derived from Salvia miltiorrhiza that can play a therapeutic role in different cancers, including PCa. Several studies have shown that Tanshinone can target various molecular pathways of PCa, including the signal transducer and activator of transcription 3 (STAT3) pathway, androgen receptor (AR) pathway, phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway, and mitogen-activated protein kinase (MAPK) pathway, which will affect the release of pro-inflammatory cytokines and affect cell proliferation, apoptosis, tumor metabolism, genomic stability, and tumor drug resistance. Thus, the occurrence and development of PCa cells are inhibited. In this review, we summarized the in vivo and in vitro evidence of Tanshinone against prostate cancer and discussed the effect of Tanshinone on nuclear factor kappa-B (NF-κB), AR, and mTOR. At the same time, we conducted a network pharmacology analysis on the four main components of Tanshinone to further screen the possible targets of Tanshinone against prostate cancer and provide ideas for future research.