DNA G-Quadruplexes as Targets for Natural Product Drug Discovery

DNA guanine(G)-quadruplexes(G4s)are unique secondary structures formed by two or more stacked Gtetrads in G-rich DNA sequences.These structures have been found to play a crucial role in highly transcribed genes,especially in cancer-related oncogenes,making them attractive targets for cancer therapeutics.Significantly,targeting oncogene promoter G4 structures has emerged as a promising strategy to address the challenge of undruggable and drug-resistant proteins,such as MYC,BCL2,KRAS,and EGFR.Natural products have long been an important source of drug discovery,particularly in the fields of cancer and infectious diseases.Noteworthy progress has recently been made in the discovery of naturally occurring DNA G4-targeting drugs.Numerous DNA G4s,such as MYC-G4,BCL2-G4,KRAS-G4,PDGFR-b-G4,VEGF-G4,and telomeric-G4,have been identified as potential targets of natural products,including berberine,telomestatin,quindoline,sanguinarine,isaindigotone,and many others.Herein,we summarize and evaluate recent advancements in natural and nature-derived DNA G4 binders,focusing on understanding the structural recognition of DNA G4s by small molecules derived from nature.We also discuss the challenges and opportunities associated with developing drugs that target DNA G4s.

The paradoxical functions of EGFR during breast cancer progression

The epidermal growth factor receptor(EGFR)is one of the most well-studied signaling pathways in cancer progression.As a result,numerous therapeutics including small-molecule inhibitors and monoclonal antibodies have been developed to target this critical oncogenic driver.Several of these EGFR inhibitors(EGFRi)have been evaluated in metastatic breast cancer,as high-level EGFR expression in primary tumors correlates with the highly aggressive basal-like phenotype and predicts for poor patient prognosis.Surprisingly,these trials have been unanimously unsuccessful at improving patient outcomes.Numerous factors,such as lack of proper patient selection may have contributed to the failure of these trials.However,recent findings suggest that there are fundamental changes in EGFR signaling that take place during primary tumor invasion,dissemination and ultimate metastasis of breast cancer cells.Herein,we review the outcomes of EGFR-targeted clinical trials in breast cancer and explore our current understanding of EGFR signaling within primary mammary tumors and how these events are altered in the metastatic setting.Overall,we put forth the hypothesis that fundamental changes in EGFR signaling between primary and metastatic tumors,a process we term the‘EGFR paradox,’contribute to the clinically observed inherent resistance to EGFRi.Furthermore,this hypothesis introduces the possibility of utilizing EGFR agonism as a potential therapeutic approach for the treatment of metastatic breast cancer.

Microbiota or short-chain fatty acids: which regulates diabetes?

Diabetes mellitus,with sustained high-sugar levels in the blood,has been steadily rising in prevalence worldwide.Around 12–14%of the US population has been diagnosed with diabetes in recent years.1 One major reason for the rise of diabetes is dietary changes.Increased consumption of processed carbohydrates with inadequate consumption of dietary fiber(DF)has been recognized as a major risk factor for diabetes,as hypothesized several decades ago by Trowell.

LIX1-like protein drives hepatic stellate cell activation to promote liver fibrosis by regulation of chemokine mRNA stability

Dear Editor,Hepatic stellate cells(HSCs)play a key role in the fibrotic response,thus inactivating activated HSC could be a potential therapy for fibrosis.^(1,2) CCL20 expressed by HSCs and macrophages,may serve as a mediator of in flammation and fibrosis.^(3) LIX1L is a putative RNA-binding protein(RBP)that may play an important role in post-transcriptional gene regulation.^(4) However,the biological function of LIX1L in liver fibrosis remains unclear,we therefore aimed to characterize its functions in HSC activation and liver fibrosis.

Current technologies to identify protein kinase substrates in high throughput

Since the discovery of protein phosphorylation as an important modulator of many cellular processes, the involvement of protein kinases in diseases, such as cancer, diabetes, cardiovascular diseases, and central nervous system pathologies, has been extensively documented. Our understanding of many disease pathologies at the molecular level, therefore, requires the comprehensive identification of substrates targeted by protein kinases. In this review, we focus on recent techniques for kinase substrate identification in high throughput, in particular on genetic and proteomic approaches. Each method with its inherent advantages and limitations is discussed.

Crawling of effector T cells on extracellular matrix： role of integrins in interstitial migration in inflamed tissues

Tcells are one of the most migratory cells in the body. The development and function of T cells depend on their interaction with other cells, which is, in turn, dependent on optimal cell migra- tion. T cells migrate largely in three dif- ferent ways： rapid distribution via blood vessels through hemodynamic move- ment, transendothelial migration and interstitial movement. Transendothelial migration involves sequential activation of selectins, chemokine receptors and integrin molecules expressed by migrat- ing T cells, leading to extravasation from blood vessel into local tissue environ- ments.