Purpurogallin is a novel mitogen-activated protein kinase kinase 1/2 inhibitor that suppresses esophageal squamous cell carcinoma growth in vitro and in vivo

Therapeutic implications of signaling pathways and tumor microenvironment interactions in esophageal cancer

Esophageal cancer (EC) is significantly influenced by the tumor microenvironment (TME) and altered signaling pathways. Downregulating these pathways in EC is essential for suppressing tumor development, preventing metastasis, and enhancing therapeutic outcomes. This approach can increase tumor sensitivity to treatments, enhance patient outcomes, and inhibit cancer cell proliferation and spread. The TME, comprising cellular and non-cellular elements surrounding the tumor, significantly influences EC's development, course, and treatment responsiveness. Understanding the complex relationships within the TME is crucial for developing successful EC treatments. Immunotherapy is a vital TME treatment for EC. However, the heterogeneity within the TME limits the application of anticancer drugs outside clinical settings. Therefore, identifying reliable microenvironmental biomarkers that can detect therapeutic responses before initiating therapy is crucial. Combining approaches focusing on EC signaling pathways with TME can enhance treatment outcomes. This integrated strategy aims to interfere with essential signaling pathways promoting cancer spread while disrupting factors encouraging tumor development. Unraveling aberrant signaling pathways and TME components can lead to more focused and efficient treatment approaches, identifying specific cellular targets for treatments. Targeting the TME and signaling pathways may reduce metastasis risk by interfering with mechanisms facilitating cancer cell invasion and dissemination. In conclusion, this integrative strategy has significant potential for improving patient outcomes and advancing EC research and therapy. This review discusses the altered signaling pathways and TME in EC, focusing on potential future therapeutics.

Unlocking the Therapeutic Potential of BCL-2 Associated Protein Family: Exploring BCL-2 Inhibitors in Cancer Therapy

Apoptosis, programmed cell death pathway, is a vital physiological mechanism that ensures cellular homeostasis and overall cellular well-being. In the context of cancer, where evasion of apoptosis is a hallmark, the overexpression of anti-apoptotic proteins like Bcl2, Bcl-xL and Mcl-1 has been documented. Consequently, these proteins have emerged as promising targets for therapeutic interventions. The BCL-2 protein family is central to apoptosis and plays a significant importance in determining cellular fate serving as a critical determinant in this biological process. This review offers a comprehensive exploration of the BCL-2 protein family, emphasizing its dual nature. Specifically, certain members of this family promote cell survival (known as anti-apoptotic proteins), while others are involved in facilitating cell death (referred to as pro-apoptotic and BH3-only proteins). The potential of directly targeting these proteins is examined, particularly due to their involvement in conferring resistance to traditional cancer therapies. The effectiveness of such targeting strategies is also discussed, considering the tumor's propensity for anti-apoptotic pathways. Furthermore, the review highlights emerging research on combination therapies, where BCL-2 inhibitors are used synergistically with other treatments to enhance therapeutic outcomes. By understanding and manipulating the BCL-2 family and its associated pathways, we open doors to innovative and more effective cancer treatments, offering hope for resistant and aggressive cases.

Role of Phytoconstituents in Cancer Treatment: A Review

Over the years, natural compounds have become a significant advancement in cancer treatment, primarily due to their effectiveness, safety, bio-functionality, and wide range of molecular structures. They are now increasingly preferred in drug discovery due to these attributes. These compounds, whether occurring naturally or with synthetic modifications, find applications in various fields like biology, medicine, and engineering. While chemotherapy has been a successful method for treating cancer, it comes with systemic toxicity. To address this issue, researchers and medical practitioners are exploring the concept of combinational chemotherapy. This approach aims to reduce toxicity by using a mix of natural substances and their derivatives in clinical trials and prescription medications. Among the most extensively studied natural anticancer compounds are quercetin, curcumin, vincristine, and vinblastine. These compounds play crucial roles as immunotherapeutics and chemosensitizers, both as standalone treatments and in combination therapies with specific mechanisms. This review article provides a concise overview of the functions, potentials, and combinations of natural anticancer compounds in cancer treatment, along with their mechanisms of action and clinical applications.

Purpurogallin Reverses Neuronal Apoptosis and Enhances "M2" Polarization of Microglia Under Ischemia via Mediating the miR-124-3p/TRAF6/NF-κB Axis

Purpurogallin (PPG) has been demonstrated to exert an anti-inflammatory function in neurological diseases. This study aimed at investigating the role of PPG on microglial polarization post ischemic stroke as well as the underlying mechanism. Mouse hippocampal neurons HT-22 and microglial BV2 cells were treated by oxygen and glucose deprivation to simulate an in-vitro ischemia model. qRT-PCR and ELISA examined expression of cytokines in microglia. CCK8 and flow cytometry measured HT-22 cell viability and apoptosis, respectively. The levels of miR-124-3p and TRAF6/NF-κB were determined. A mouse cerebral ischemia model was set up using middle cerebral artery occlusion (MCAO) method. After being dealt with PPG, the neurological functions, brain edema, neuronal apoptosis, and microglia activation of the mice were evaluated. As suggested by the results, PPG transformed "M1" to "M2" polarization of BV2 cells, and abated HT-22 cell apoptosis. PPG enhanced the neurological functions, alleviated brain edema, and decreased neuroinflammatory responses, and neuronal apoptosis in the brain lesions of MCAO mice. Furthermore, PPG enhanced miR-124-3p and repressed the TRAF6/NF-κB pathway. miR-124-3p suppressed the TRAF6/NF-κB pathway by targeting TRAF6. Collectively, PPG alleviates ischemia-induced neuronal damage and microglial inflammation by modulating the miR-124-3p/TRAF6/NF-κB pathway.

Inhibitors of the PLK1 polo-box domain: drug design strategies and therapeutic opportunities in cancer

INTRODUCTION

Polo Like Kinase 1 (PLK1) is a key regulator of mitosis and its overexpression is frequently observed in a wide variety of human cancers, while often being associated with poor survival rates. Therefore, it is considered a potential and attractive target for cancer therapeutic development. The Polo like kinase family is characterized by the presence of a unique C terminal polobox domain (PBD) involved in regulating kinase activity and subcellular localization. Among the two functionally essential, druggable sites with distinct properties that PLK1 offers, targeting the PBD presents an alternative approach for therapeutic development.

AREAS COVERED

Significant progress has been made in progressing from the peptidic PBD inhibitors first identified, to peptidomimetic and recently drug-like small molecules. In this review, the rationale for targeting the PBD over the ATP binding site is discussed, along with recent progress, challenges, and outlook.

EXPERT OPINION

The PBD has emerged as a viable alternative target for the inhibition of PLK1, and progress has been made in using compounds to elucidate mechanistic aspects of activity regulation and in determining roles of the PBD. Studies have resulted in proof of concept of in vivo efficacy suggesting promise for PBD binders in clinical development.

Natural Products as Anticancer Agents: Current Status and Future Perspectives

Natural products have been an invaluable and useful source of anticancer agents over the years. Several compounds have been synthesized from natural products by modifying their structures or by using naturally occurring compounds as building blocks in the synthesis of these compounds for various purposes in different fields, such as biology, medicine, and engineering. Multiple modern and costly treatments have been applied to combat cancer and limit its lethality, but the results are not significantly refreshing. Natural products, which are a significant source of new therapeutic drugs, are currently being investigated as potential cytotoxic agents and have shown a positive trend in preclinical research and have prompted numerous innovative strategies in order to combat cancer and expedite the clinical research. Natural products are becoming increasingly important for drug discovery due to their high molecular diversity and novel biofunctionality. Furthermore, natural products can provide superior efficacy and safety due to their unique molecular properties. The objective of the current review is to provide an overview of the emergence of natural products for the treatment and prevention of cancer, such as chemosensitizers, immunotherapeutics, combinatorial therapies with other anticancer drugs, novel formulations of natural products, and the molecular mechanisms underlying their anticancer properties.

Natural Products for Esophageal Cancer Therapy: From Traditional Medicine to Modern Drug Discovery

Esophageal cancer (EC) is one of the most malignant types of cancer worldwide and has a high incidence and mortality rate in Asian countries. When it comes to treating EC, although primary methods such as chemotherapy and surgery exist, the prognosis remains poor. The purpose of this current research is to review the range of effects that natural products have on cancer by analyzing studies conducted on EC. Fifty-seven studies were categorized into four anti-cancer mechanisms, as well as clinical trials. The studies that were scrutinized in this research were all reported within five years. The majority of the substances reviewed induced apoptosis in EC, acting on a variety of mechanisms. Taken together, this study supports the fact that natural products have the potential to act as a candidate for treating EC.

Conversion of lignin-derived 3-methoxycatechol to the natural product purpurogallin using bacterial P450 GcoAB and laccase CueO

Purpurogallin is a natural benzotropolone extracted from Quercus spp, which has antioxidant, anticancer, and anti-inflammatory properties. Purpurogallin is typically synthesized from pyrogallol using enzymatic or metal catalysts, neither economically feasible nor environmentally friendly. 3-Methoxycatechol (3-MC) is a lignin-derived renewable chemical with the potential to be a substrate for the biosynthesis of purpurogallin. In this study, we designed a pathway to produce purpurogallin from 3-MC. We first characterized four bacterial laccases and identified the laccase CueO from Escherichia coli, which converts pyrogallol to purpurogallin. Then, we used CueO and the P450 GcoAB reported to convert 3-MC to pyrogallol, to construct a method for producing purpurogallin directly from 3-MC. A total of 0.21 ± 0.05 mM purpurogallin was produced from 5 mM 3-MC by whole-cell conversion. This study provides a new method to enable efficient and sustainable synthesis of purpurogallin and offers new insights into lignin valorization. KEY POINTS: • Screening four bacterial laccases for converting pyrogallol to purpurogallin. • Laccase CueO from Escherichia coli presenting the activity for purpurogallin yield. • A novel pathway for converting lignin-derived 3-methoxycatechol to purpurogallin.

Functional roles of the SHCBP1 and KIF23 interaction in modulating the cell-cycle and cisplatin resistance of head and neck squamous cell carcinoma

BACKGROUND

This study aimed to explore the functional roles of Shc SH2-domain-binding protein 1 (SHCBP1) and Kinesin Family Member 23 (KIF23) in HPV-negative head and neck squamous cell carcinoma (HNSCC).

METHODS

Bioinformatic analysis was conducted using data from The Cancer Genome Atlas (TCGA) and GSE103322. HNSCC cell lines were used for in vitro and in vivo analysis.

RESULTS

SHCBP1 upregulation was associated with unfavorable survival. SHCBP1 knockdown reduced cell proliferation and increased the cisplatin sensitivity of SCC9/SCC25 cells. SHCBP1 interacted with KIF23 via its Nesd homology domain (NHD) domain, which was important for its nucleus localization. SHCBP1 positively modulated KIF23 expression and activated phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), extracellular signal regulated kinase (ERK)1/2, nuclear factor kappa B (NF/κB)-p65, and Wnt/β-catenin signaling. KIF23 knockdown abrogated cisplatin resistance induced by SHCBP1 overexpression.

CONCLUSION

SHCBP1 interacts with KIF23 and cooperatively regulates cell-cycle progression and cisplatin resistance of HNSCC tumor cells.

Advances and challenges in the treatment of esophageal cancer

Esophageal cancer (EC) is one of the most common cancers with high morbidity and mortality rates. EC includes two histological subtypes, namely esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC). ESCC primarily occurs in East Asia, whereas EAC occurs in Western countries. The currently available treatment strategies for EC include surgery, chemotherapy, radiation therapy, molecular targeted therapy, and combinations thereof. However, the prognosis remains poor, and the overall five-year survival rate is very low. Therefore, achieving the goal of effective treatment remains challenging. In this review, we discuss the latest developments in chemotherapy and molecular targeted therapy for EC, and comprehensively analyze the application prospects and existing problems of immunotherapy. Collectively, this review aims to provide a better understanding of the currently available drugs through in-depth analysis, promote the development of new therapeutic agents, and eventually improve the treatment outcomes of patients with EC.

Patient-derived xenograft: a developing tool for screening biomarkers and potential therapeutic targets for human esophageal cancers

Esophageal cancer (EC) represents a human malignancy, diagnosed often at the advanced stage of cancer and resulting in high morbidity and mortality. The development of precision medicine allows for the identification of more personalized therapeutic strategies to improve cancer treatment. By implanting primary cancer tissues into immunodeficient mice for expansion, patient-derived xenograft (PDX) models largely maintain similar histological and genetic representations naturally found in patients' tumor cells. PDX models of EC (EC-PDX) provide fine platforms to investigate the tumor microenvironment, tumor genomic heterogeneity, and tumor response to chemoradiotherapy, which are necessary for new drug discovery to combat EC in addition to optimization of current therapeutic strategies for EC. In this review, we summarize the methods used for establishing EC-PDX models and investigate the utilities of EC-PDX in screening predictive biomarkers and potential therapeutic targets. The challenge of this promising research tool is also discussed.

A New Family of Jumonji C Domain-Containing KDM Inhibitors Inspired by Natural Product Purpurogallin

Aberrant epigenetic modifications are involved in cancer development. Jumonji C domain-containing histone lysine demethylases (KDMs) are found mainly up-regulated in breast, prostate, and colon cancer. Currently, growing interest is focusing on the identification and development of new inhibitors able to block the activity of KDMs and thus reduce tumor progression. KDM4A is known to play a role in several cellular physiological processes, and was recently found overexpressed in a number of pathological states, including cancer. In this work, starting from the structure of purpurogallin 9aa, previously identified as a natural KDM4A inhibitor, we synthesized two main sets of compound derivatives in order to improve their inhibitory activity against KDM4A in vitro and in cells, as well as their antitumor action. Based on the hypothetical biogenesis of the 5-oxo-5H-benzo[7]annulene skeleton of the natural product purpurogallin (Salfeld, 1960; Horner et al., 1961; Dürckheimer and Paulus, 1985; Tanaka et al., 2002; Yanase et al., 2005) the pyrogallol and catechol units were first combined with structural modifications at different positions of the aryl ring using enzyme-mediated oxidative conditions, generating a series of benzotropolone analogs. Two of the synthetic analogs of purpurogallin, 9ac and 9bc, showed an efficient inhibition (50 and 80%) of KDM4A in enzymatic assays and in cells by increasing levels of its specific targets, H3K9me3/2 and H3K36me3. However, these two compounds/derivatives did not induce cell death. We then synthesized a further set of analogs of these two compounds with greater structural diversification. The most potent of these analogs, 9bf, displayed the highest KDM4A inhibitory enzymatic activity in vitro (IC₅₀ of 10.1 and 24.37 μM) in colon cancer cells, and the strongest antitumor action in several solid and hematological human cancer cell lines with no toxic effect in normal cells. Our findings suggest that further development of this compound and its derivatives may lead to the identification of new therapeutic antitumor agents acting through inhibition of KDM4A.