A novel combination therapy with Cabozantinib and Honokiol effectively inhibits c-Met-Nrf2-induced renal tumor growth through increased oxidative stress

Identification of a 7H-pyrrolo[2,3-d]pyrimidin derivatives as selective type II c-Met/Axl inhibitors with potent antitumor efficacy

In this study, we reported the discovery of a novel type II c-Met/Axl inhibitor, characterized by using 4-amino-7H-pyrrolo[2,3-d]pyrimidine as a hinge region binder. Through a systematic exploration of the structure-activity relationship, based on the clinically reported c-Met inhibitor BMS-777607, we identified the optimized compound 22a. 22a exhibited remarkable potency against c-Met and Axl kinases, with IC50 values of 1 nM and 10 nM, respectively, and demonstrated over 100-fold selectivity to other members of the TAM subfamily. Furthermore, compared to cabozantinib, compound 22a displayed superior anti-tumor proliferation activity across a range of solid tumors. 22a demonstrated excellent drug-like properties, achieving a bioavailability of 174.2 % in rats. In established MKN-45 and HCT116 xenograft tumor models, compound 22a achieved tumor growth inhibition (TGI) rates of 98.2 % and 87.2 %, respectively, at a dosage of 1 mg/kg. Taken together, compound 22a is a selective dual c-Met/Axl inhibitor with significant potential as a clinical candidate.

AXL signaling in cancer: from molecular insights to targeted therapies

AXL, a member of the TAM receptor family, has emerged as a potential target for advanced-stage human malignancies. It is frequently overexpressed in different cancers and plays a significant role in various tumor-promoting pathways, including cancer cell proliferation, invasion, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, stemness, DNA damage response, acquired therapeutic resistance, immunosuppression, and inflammatory responses. Beyond oncology, AXL also facilitates viral infections, including SARS-CoV-2 and Zika highlighting its importance in both cancer and virology. In preclinical models, small-molecule kinase inhibitors targeting AXL have shown promising anti-tumorigenic potential. This review primarily focuses on the induction, regulation and biological functions of AXL in mediating these tumor-promoting pathways. We discuss a range of therapeutic strategies, including recently developed small-molecule tyrosine kinase inhibitors (TKIs), monoclonal antibodies, and antibody-drug conjugates (ADCs), anti-AXL-CAR, and combination therapies. These interventions are being examined in both preclinical and clinical studies, offering the potential for improved drug sensitivity and therapeutic efficacy. We further discuss the mechanisms of acquired therapeutic resistance, particularly the crosstalk between AXL and other critical receptor tyrosine kinases (RTKs) such as c-MET, EGFR, HER2/HER3, VEGFR, PDGFR, and FLT3. Finally, we highlight key research areas that require further exploration to enhance AXL-mediated therapeutic approaches for improved clinical outcomes.

Nrf2 Signaling in Renal Cell Carcinoma: A Potential Candidate for the Development of Novel Therapeutic Strategies

Renal cell carcinoma (RCC) is the most common type of kidney cancer arising from renal tubular epithelial cells and is characterized by a high aggressive behavior and invasiveness that lead to poor prognosis and high mortality rate. Diagnosis of RCC is generally incidental and occurs when the stage is advanced and the disease is already metastatic. The management of RCC is further complicated by an intrinsic resistance of this malignancy to chemotherapy and radiotherapy, which aggravates the prognosis. For these reasons, there is intense research focused on identifying novel biomarkers which may be useful for a better prognostic assessment, as well as molecular markers which could be utilized for targeted therapy. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcriptional factor that has been identified as a key modulator of oxidative stress response, and its overexpression is considered a negative prognostic feature in several types of cancers including RCC, since it is involved in various key cancer-promoting functions such as proliferation, anabolic metabolism and resistance to chemotherapy. Given the key role of Nrf2 in promoting tumor progression, this enzyme could be a promising biomarker for a more accurate prediction of RCC course and it can also represent a valuable therapeutic target. In this review, we provide a comprehensive literature analysis of studies that have explored the role of Nrf2 in RCC, underlining the possible implications for targeted therapy.

The Crosstalk between Autophagy and Nrf2 Signaling in Cancer: from Biology to Clinical Applications

Autophagy is a catabolic process that has been conserved throughout evolution, serving to degrade and recycle cellular components and damaged organelles. Autophagy is activated under various stress conditions, such as nutrient deprivation, viral infections, and genotoxic stress, and operates in conjunction with other stress response pathways to mitigate oxidative damage and maintain cellular homeostasis. One such pathway is the Nrf2-Keap1-ARE signaling axis, which functions as an intrinsic antioxidant defense mechanism and has been implicated in cancer chemoprevention, tumor progression, and drug resistance. Recent research has identified a link between impaired autophagy, mediated by the autophagy receptor protein p62, and the activation of the Nrf2 pathway. Specifically, p62 facilitates Keap1 degradation through selective autophagy, leading to the translocation of Nrf2 into the nucleus, where it transcriptionally activates downstream antioxidant enzyme expression, thus safeguarding cells from oxidative stress. Furthermore, Nrf2 regulates p62 transcription, so a positive feedback loop involving p62, Keap1, and Nrf2 is established, which amplifies the protective effects on cells. This paper aims to provide a comprehensive review of the roles of Nrf2 and autophagy in cancer progression, the regulatory interactions between the Nrf2 pathway and autophagy, and the potential applications of the Nrf2-autophagy signaling axis in cancer therapy.

Luteolin protects against myocardial ischemia/reperfusion injury by reducing oxidative stress and apoptosis through the p53 pathway

OBJECTIVE

Myocardial ischemia/reperfusion injury (MIRI) is an obstacle to the success of cardiac reperfusion therapy. This study explores whether luteolin can mitigate MIRI by regulating the p53 signaling pathway.

METHODS

Model mice were subjected to a temporary surgical ligation of the left anterior descending coronary artery, and administered luteolin. The myocardial infarct size, myocardial enzyme levels, and cardiac function were measured. Latent targets and signaling pathways were screened using network pharmacology and molecular docking. Then, proteins related to the p53 signaling pathway, apoptosis and oxidative stress were measured. Hypoxia/reoxygenation (HR)-incubated HL1 cells were used to validate the effects of luteolin in vitro. In addition, a p53 agonist and an inhibitor were used to investigate the mechanism.

RESULTS

Luteolin reduced the myocardial infarcted size and myocardial enzymes, and restored cardiac function in MIRI mice. Network pharmacology identified p53 as a hub target. The bioinformatic analyses showed that luteolin had anti-apoptotic and anti-oxidative properties. Additionally, luteolin halted the activation of p53, and prevented both apoptosis and oxidative stress in myocardial tissue in vivo. Furthermore, luteolin inhibited cell apoptosis, JC-1 monomer formation, and reactive oxygen species elevation in HR-incubated HL1 cells in vitro. Finally, the p53 agonist NSC319726 downregulated the protective attributes of luteolin in the MIRI mouse model, and both luteolin and the p53 inhibitor pifithrin-α demonstrated a similar therapeutic effect in the MIRI mice.

CONCLUSION

Luteolin effectively treats MIRI and may ameliorate myocardial damage by regulating apoptosis and oxidative stress through its targeting of the p53 signaling pathway. Please cite this article as: Zhai P, Ouyang XH, Yang ML, Lin L, Li JY, Li YM, Cheng X, Zhu R, Hu DS. Luteolin protects against myocardial ischemia/reperfusion injury by reducing oxidative stress and apoptosis through the p53 pathway. J Integr Med. 2024; 22(6): 652-664.

IL-32γ Induced Autophagy Through Suppression of MET and mTOR Pathways in Liver Tumor Growth Inhibition

Interleukin-32γ (IL-32γ) has diverse functions in various malignancies. In this study, we investigated the role of IL-32γ in autophagy induction in liver cancer cells and delineated the underlying mechanisms. We found that the increased IL-32γ expression inhibited the growth, cell cycle progression, and migration of HepG2 and Hep3B cell lines; it also decreased the expression of related proteins. Furthermore, the IL-32γ overexpression induced autophagy, as indicated by the number of puncta, the expression of LC3, and the expression of autophagy-related markers. The expression levels of LAMP1, a protein essential for autophagosome formation, and colocalization with LC3 also increased. Big data analysis revealed that the expression of MET, a well-known target of autophagy, and the expression of mTOR and mTOR-related proteins were decreased by the IL-32γ overexpression. The combination treatment of MET inhibitor, cabozantinib (2 µM), and IL-32γ overexpression further increased the number of puncta, the colocalization of LC3 and LAMP1, and the expression of autophagy-related proteins. In vivo, liver tumor growth was suppressed in the IL-32γ-overexpressing mouse model, and autophagy induction was confirmed by the increased expression of LC3 and LAMP1 and the decreased expression of autophagy pathway markers (MET and mTOR). Autophagy was also decreased in the liver tumor sample of human patients. ROC curve and spearman analysis revealed that the expression levels of LC3 and IL-32γ were significantly correlated in human tumor serum and tissues. Therefore, IL-32γ overexpression induced autophagy in liver tumors through the suppression of MET and mTOR pathways critical for tumor growth inhibition.

The role of natural products versus miRNA in renal cell carcinoma: implications for disease mechanisms and diagnostic markers

Natural products are chemical compounds produced by living organisms. They are isolated and purified to determine their function and can potentially be used as therapeutic agents. The ability of some bioactive natural products to modify the course of cancer is fascinating and promising. In the past 50 years, there have been advancements in cancer therapy that have increased survival rates for localized tumors. However, there has been little progress in treating advanced renal cell carcinoma (RCC), which is resistant to radiation and chemotherapy. Oncogenes and tumor suppressors are two roles played by microRNAs (miRNAs). They are involved in important pathogenetic mechanisms like hypoxia and epithelial-mesenchymal transition (EMT); they control apoptosis, cell growth, migration, invasion, angiogenesis, and proliferation through target proteins involved in various signaling pathways. Depending on their expression pattern, miRNAs may identify certain subtypes of RCC or distinguish tumor tissue from healthy renal tissue. As diagnostic biomarkers of RCC, circulating miRNAs show promise. There is a correlation between the expression patterns of several miRNAs and the prognosis and diagnosis of patients with RCC. Potentially high-risk primary tumors may be identified by comparing original tumor tissue with metastases. Variations in miRNA expression between treatment-sensitive and therapy-resistant patients' tissues and serum allow for the estimation of responsiveness to target therapy. Our knowledge of miRNAs' function in RCC etiology has a tremendous uptick. Finding and validating their gene targets could have an immediate effect on creating anticancer treatments based on miRNAs. Several miRNAs have the potential to be used as biomarkers for diagnosis and prognosis. This review provides an in-depth analysis of the current knowledge regarding natural compounds and their modes of action in combating cancer. Also, this study aims to give information about the diagnostic and prognostic value of miRNAs as cancer biomarkers and their involvement in the pathogenesis of RCC.

Is Autophagy Targeting a Valid Adjuvant Strategy in Conjunction with Tyrosine Kinase Inhibitors?

Tyrosine kinase inhibitors (TKIs) represent a relatively large class of small-molecule inhibitors that compete with ATP for the catalytic binding site of tyrosine kinase proteins. While TKIs have demonstrated effectiveness in the treatment of multiple malignancies, including chronic myelogenous leukemia, gastrointestinal tumors, non-small cell lung cancers, and HER2-overexpressing breast cancers, as is almost always the case with anti-neoplastic agents, the development of resistance often imposes a limit on drug efficacy. One common survival response utilized by tumor cells to ensure their survival in response to different stressors, including anti-neoplastic drugs, is that of autophagy. The autophagic machinery in response to TKIs in multiple tumor models has largely been shown to be cytoprotective in nature, although there are a number of cases where autophagy has demonstrated a cytotoxic function. In this review, we provide an overview of the literature examining the role that autophagy plays in response to TKIs in different preclinical tumor model systems in an effort to determine whether autophagy suppression or modulation could be an effective adjuvant strategy to increase efficiency and/or overcome resistance to TKIs.

Natural products for enhancing the sensitivity or decreasing the adverse effects of anticancer drugs through regulating the redox balance

Redox imbalance is reported to play a pivotal role in tumorigenesis, cancer development, and drug resistance. Severe oxidative damage is a general consequence of cancer cell responses to treatment and may cause cancer cell death or severe adverse effects. To maintain their longevity, cancer cells can rescue redox balance and enter a state of resistance to anticancer drugs. Therefore, targeting redox signalling pathways has emerged as an attractive and prospective strategy for enhancing the efficacy of anticancer drugs and decreasing their adverse effects. Over the past few decades, natural products (NPs) have become an invaluable source for developing new anticancer drugs due to their high efficacy and low toxicity. Increasing evidence has demonstrated that many NPs exhibit remarkable antitumour effects, whether used alone or as adjuvants, and are emerging as effective approaches to enhance sensitivity and decrease the adverse effects of conventional cancer therapies by regulating redox balance. Among them are several novel anticancer drugs based on NPs that have entered clinical trials. In this review, we summarize the synergistic anticancer effects and related redox mechanisms of the combination of NPs with conventional anticancer drugs. We believe that NPs targeting redox regulation will represent promising novel candidates and provide prospects for cancer treatment in the future.

Targeting Metabolic-Redox Nexus to Regulate Drug Resistance: From Mechanism to Tumor Therapy

Drug resistance is currently one of the biggest challenges in cancer treatment. With the deepening understanding of drug resistance, various mechanisms have been revealed, including metabolic reprogramming and alterations of redox balance. Notably, metabolic reprogramming mediates the survival of tumor cells in harsh environments, thereby promoting the development of drug resistance. In addition, the changes during metabolic pattern shift trigger reactive oxygen species (ROS) production, which in turn regulates cellular metabolism, DNA repair, cell death, and drug metabolism in direct or indirect ways to influence the sensitivity of tumors to therapies. Therefore, the intersection of metabolism and ROS profoundly affects tumor drug resistance, and clarifying the entangled mechanisms may be beneficial for developing drugs and treatment methods to thwart drug resistance. In this review, we will summarize the regulatory mechanism of redox and metabolism on tumor drug resistance and highlight recent therapeutic strategies targeting metabolic-redox circuits, including dietary interventions, novel chemosynthetic drugs, drug combination regimens, and novel drug delivery systems.

Recent advances of honokiol：pharmacological activities, manmade derivatives and structure-activity relationship

Honokiol (HNK) is a typical natural biphenyl polyphenol compound. It has been proven to have a wide range of biological activities, including pharmacological effects such as anti-cancer, anti-inflammatory, neuroprotective, and antimicrobial. However, due to the poor stability, water solubility, and bioavailability of HNK, HNK has not been used in clinical treatment. This article reviews the latest research on the pharmacological activity of HNK and summarizes the HNK derivatives designed and improved by several researchers. Reviewing these contents could promote the research process of HNK and guide the design of better HNK derivatives for clinical application in the future.

c-MET pathway in human malignancies and its targeting by natural compounds for cancer therapy

BACKGROUND

c-MET is a receptor tyrosine kinase which is classically activated by HGF to activate its downstream signaling cascades such as MAPK, PI3K/Akt/mTOR, and STAT3. The c-MET modulates cell proliferation, epithelial-mesenchymal transition (EMT), immune response, morphogenesis, apoptosis, and angiogenesis. The c-MET has been shown to serve a prominent role in embryogenesis and early development. The c-MET pathway is deregulated in a broad range of malignancies, due to overexpression of ligands or receptors, genomic amplification, and MET mutations. The link between the deregulation of c-MET signaling and tumor progression has been well-documented. Overexpression or overactivation of c-MET is associated with dismal clinical outcomes and acquired resistance to targeted therapies. Since c-MET activation results in the triggering of oncogenic pathways, abrogating the c-MET pathway is considered to be a pivotal strategy in cancer therapeutics. Herein, an analysis of role of the c-MET pathway in human cancers and its relevance in bone metastasis and therapeutic resistance has been undertaken. Also, an attempt has been made to summarize the inhibitory activity of selected natural compounds towards c-MET signaling in cancers.

METHODS

The publications related to c-MET pathway in malignancies and its natural compound modulators were obtained from databases such as PubMed, Scopus, and Google Scholar and summarized based on PRISMA guidelines. Some of the keywords used for extracting relevant literature are c-MET, natural compound inhibitors of c-MET, c-MET in liver cancer, c-MET in breast cancer, c-MET in lung cancer, c-MET in pancreatic cancer, c-MET in head and neck cancer, c-MET in bone metastasis, c-MET in therapeutic resistance, and combination of c-MET inhibitors and chemotherapeutic agents. The chemical structure of natural compounds was verified in PubChem database.

RESULTS

The search yielded 3935 publications, of which 195 reference publications were used for our analysis. Clinical trials were referenced using ClinicalTrials.gov identifier. The c-MET pathway has been recognized as a prominent target to combat the growth, metastasis, and chemotherapeutic resistance in cancers. The key role of the c-MET in bone metastasis as well as therapeutic resistance has been elaborated. Also, suppressive effect of selected natural compounds on the c-MET pathway in clinical/preclinical studies has been discussed.

Honokiol suppress the PD-L1 expression to improve anti-tumor immunity in lung cancer

Lung cancer is a serious health issue globally, and current treatments have proven to be inadequate. Therefore, immune checkpoint inhibitors (ICIs) that target the PD-1/PD-L1 pathway have become a viable treatment option in lun cancer. Honokiol, a lignan derived from Magnolia officinalis, has been found to possess anti-inflammatory, antioxidant, and antitumor properties. Our research found that honokiol can effectively regulate PD-L1 through network pharmacology and transcriptome analysis. Cell experiments showed that honokiol can significantly reduce PD-L1 expression in cells with high PD-L1 expression. Molecular docking, cellular thermal shift assay (CETSA) and Bio-Layer Interferometry (BLI)indicated that Honokiol can bind to PD-L1. Co-culture experiments on lung cancer cells and T cells demonstrated that honokiol mediates PD-L1 degradation, stimulates T cell activation, and facilitates T cell killing of tumor cells. Moreover, honokiol activates CD4 + and CD8 + T cell infiltration in vivo, thus suppressing tumor growth in C57BL/6 mice. In conclusion, this study has demonstrated that honokiol can inhibit the growth of lung cancer by targeting tumor cell PD-L1, suppressing PD-L1 expression, blocking the PD-1/PD-L1 pathway, and enhancing anti-tumor immunity.