Systematic Review of Gossypol/AT-101 in Cancer Clinical Trials

Exploring the mystery of tumor metabolism: Warburg effect and mitochondrial metabolism fighting side by side

The metabolic reconfiguration of tumor cells constitutes a pivotal aspect of tumor proliferation and advancement. This study delves into two primary facets of tumor metabolism: the Warburg effect and mitochondrial metabolism, elucidating their contributions to tumor dominance. The Warburg effect facilitates efficient energy acquisition by tumor cells through aerobic glycolysis and lactic acid fermentation, offering metabolic advantages conducive to growth and proliferation. Simultaneously, mitochondrial metabolism, serving as the linchpin of sustained tumor vitality, orchestrates the tricarboxylic acid cycle and electron transport chain, furnishing a steadfast and dependable wellspring of biosynthesis for tumor cells. Regarding targeted therapy, this discourse examines extant strategies targeting tumor glycolysis and mitochondrial metabolism, underscoring their potential efficacy in modulating tumor metabolism while envisaging future research trajectories and treatment paradigms in the realm of tumor metabolism. By means of a thorough exploration of tumor metabolism, this study aspires to furnish crucial insights into the regulation of tumor metabolic processes, thereby furnishing valuable guidance for the development of novel therapeutic modalities. This comprehensive deliberation is poised to catalyze advancements in tumor metabolism research and offer novel perspectives and pathways for the formulation of cancer treatment strategies in the times ahead.

Mcl-1 Protein and Viral Infections: A Narrative Review

MCL-1 is the prosurvival member of the Bcl-2 family. It prevents the induction of mitochondria-dependent apoptosis. The molecular mechanisms dictating the host cell viability gain importance in the context of viral infections. The premature apoptosis of infected cells could interrupt the pathogen replication cycle. On the other hand, cell death following the effective assembly of progeny particles may facilitate virus dissemination. Thus, various viruses can interfere with the apoptosis regulation network to their advantage. Research has shown that viral infections affect the intracellular amount of MCL-1 to modify the apoptotic potential of infected cells, fitting it to the "schedule" of the replication cycle. A growing body of evidence suggests that the virus-dependent deregulation of the MCL-1 level may contribute to several virus-driven diseases. In this work, we have described the role of MCL-1 in infections caused by various viruses. We have also presented a list of promising antiviral agents targeting the MCL-1 protein. The discussed results indicate targeted interventions addressing anti-apoptotic MCL1 as a new therapeutic strategy for cancers as well as other diseases. The investigation of the cellular and molecular mechanisms involved in viral infections engaging MCL1 may contribute to a better understanding of the regulation of cell death and survival balance.

The potential roles of gossypol as anticancer agent: advances and future directions

Gossypol, a polyphenolic aldehyde derived from cottonseed plants, has seen a transformation in its pharmaceutical application from a male contraceptive to a candidate for cancer therapy. This shift is supported by its recognized antitumor properties, which have prompted its investigation in the treatment of various cancers and related inflammatory conditions. This review synthesizes the current understanding of gossypol as an anticancer agent, focusing on its pharmacological mechanisms, strategies to enhance its clinical efficacy, and the status of ongoing clinical evaluations.The methodological approach to this review involved a systematic search across several scientific databases including the National Center for Biotechnology Information (NCBI), PubMed/MedLine, Google Scholar, Scopus, and TRIP. Studies were meticulously chosen to cover various aspects of gossypol, from its chemical structure and natural sources to its pharmacokinetics and confirmed anticancer efficacy. Specific MeSH terms and keywords related to gossypol's antineoplastic applications guided the search strategy.Results from selected pharmacological studies indicate that gossypol inhibits the Bcl-2 family of anti-apoptotic proteins, promoting apoptosis in tumor cells. Clinical trials, particularly phase I and II, reveal gossypol's promise as an anticancer agent, demonstrating efficacy and manageable toxicity profiles. The review identifies the development of gossypol derivatives and novel carriers as avenues to enhance therapeutic outcomes and mitigate adverse effects.Conclusively, gossypol represents a promising anticancer agent with considerable therapeutic potential. However, further research is needed to refine gossypol-based therapies, explore combination treatments, and verify their effectiveness across cancer types. The ongoing clinical trials continue to support its potential, suggesting a future where gossypol could play a significant role in cancer treatment protocols.

Advances in molecular targeted therapies to increase efficacy of (chemo)radiation therapy

Recent advances in understanding the tumor's biology in line with a constantly growing number of innovative technologies have prompted characterization of patients' individual malignancies and may display a prerequisite to treat cancer at its patient individual tumor vulnerability. In recent decades, radiation- induced signaling and tumor promoting local events for radiation sensitization were explored in detail, resulting the development of novel molecular targets. A multitude of pharmacological, genetic, and immunological principles, including small molecule- and antibody-based targeted strategies, have been developed that are suitable for combined concepts with radiation (RT) or chemoradiation therapy (CRT). Despite a plethora of promising experimental and preclinical findings, however, so far, only a very limited number of clinical trials have demonstrated a better outcome and/or patient benefit when RT or CRT are combined with targeted agents. The current review aims to summarize recent progress in molecular therapies targeting oncogenic drivers, DNA damage and cell cycle response, apoptosis signaling pathways, cell adhesion molecules, hypoxia, and the tumor microenvironment to impact therapy refractoriness and to boost radiation response. In addition, we will discuss recent advances in nanotechnology, e.g., RNA technologies and protein-degrading proteolysis-targeting chimeras (PROTACs) that may open new and innovative ways to benefit from molecular-targeted therapy approaches with improved efficacy.

Recent updates on nano-phyto-formulations based therapeutic intervention for cancer treatment

Cancer is a leading cause of death globally, with limited treatment options and several limitations. Chemotherapeutic agents often result in toxicity which long-term conventional treatment. Phytochemicals are natural constituents that are more effective in treating various diseases with less toxicity than the chemotherapeutic agents providing alternative therapeutic approaches to minimize the resistance. These phytoconstituents act in several ways and deliver optimum effectiveness against cancer. Nevertheless, the effectiveness of phyto-formulations in the management of cancers may be constrained due to challenges related to inadequate solubility, bioavailability, and stability. Nanotechnology presents a promising avenue for transforming current cancer treatment methods through the incorporation of phytochemicals into nanosystems, which possess a range of advantageous characteristics such as biocompatibility, targeted and sustained release capabilities, and enhanced protective effects. This holds significant potential for future advancements in cancer management. Herein, this review aims to provide intensive literature on diverse nanocarriers, highlighting their applications as cargos for phytocompounds in cancer. Moreover, it offers an overview of the current advancements in the respective field, emphasizing the characteristics that contribute to favourable outcomes in both in vitro and in vivo settings. Lastly, clinical development and regulatory concerns are also discussed to check on the transformation of the concept as a promising strategy for combination therapy of phytochemicals and chemotherapeutics that could lead to cancer management in the future.

Current Advances and Future Strategies for BCL-2 Inhibitors: Potent Weapons against Cancers

Targeting the intrinsic apoptotic pathway regulated by B-cell lymphoma-2 (BCL-2) antiapoptotic proteins can overcome the evasion of apoptosis in cancer cells. BCL-2 inhibitors have evolved into an important means of treating cancers by inducing tumor cell apoptosis. As the most extensively investigated BCL-2 inhibitor, venetoclax is highly selective for BCL-2 and can effectively inhibit tumor survival. Its emergence and development have significantly influenced the therapeutic landscape of hematological malignancies, especially in chronic lymphocytic leukemia and acute myeloid leukemia, in which it has been clearly incorporated into the recommended treatment regimens. In addition, the considerable efficacy of venetoclax in combination with other agents has been demonstrated in relapsed and refractory multiple myeloma and certain lymphomas. Although venetoclax plays a prominent antitumor role in preclinical experiments and clinical trials, large individual differences in treatment outcomes have been characterized in real-world patient populations, and reduced drug sensitivity will lead to disease recurrence or progression. The therapeutic efficacy may vary widely in patients with different molecular characteristics, and key genetic mutations potentially result in differential sensitivities to venetoclax. The identification and validation of more novel biomarkers are required to accurately predict the effectiveness of BCL-2 inhibition therapy. Furthermore, we summarize the recent research progress relating to the use of BCL-2 inhibitors in solid tumor treatment and demonstrate that a wealth of preclinical models have shown promising results through combination therapies. The applications of venetoclax in solid tumors warrant further clinical investigation to define its prospects.

The Musashi RNA-binding proteins in female cancers: insights on molecular mechanisms and therapeutic relevance

RNA-binding proteins have increasingly been identified as important regulators of gene expression given their ability to bind distinct RNA sequences and regulate their fate. Mounting evidence suggests that RNA-binding proteins are involved in the onset and progression of multiple malignancies, prompting increasing interest in their potential for therapeutic intervention.The Musashi RNA binding proteins Musashi-1 and Musashi-2 were initially identified as developmental factors of the nervous system but have more recently been found to be ubiquitously expressed in physiological tissues and may be involved in pathological cell behavior. Both proteins are increasingly investigated in cancers given dysregulation in multiple tumor entities, including in female malignancies. Recent data suggest that the Musashi proteins serve as cancer stem cell markers as they contribute to cancer cell proliferation and therapy resistance, prompting efforts to identify mechanisms to target them. However, as the picture remains incomplete, continuous efforts to elucidate their role in different signaling pathways remain ongoing.In this review, we focus on the roles of Musashi proteins in tumors of the female - breast, endometrial, ovarian and cervical cancer - as we aim to summarize current knowledge and discuss future perspectives.

Small molecule inhibitors for cancer metabolism: promising prospects to be explored

BACKGROUND

Abnormal metabolism is the main hallmark of cancer, and cancer metabolism plays an important role in tumorigenesis, metastasis, and drug resistance. Therefore, studying the changes of tumor metabolic pathways is beneficial to find targets for the treatment of cancer diseases. The success of metabolism-targeted chemotherapy suggests that cancer metabolism research will provide potential new targets for the treatment of malignant tumors.

PURPOSE

The aim of this study was to systemically review recent research findings on targeted inhibitors of tumor metabolism. In addition, we summarized new insights into tumor metabolic reprogramming and discussed how to guide the exploration of new strategies for cancer-targeted therapy.

CONCLUSION

Cancer cells have shown various altered metabolic pathways, providing sufficient fuel for their survival. The combination of these pathways is considered to be a more useful method for screening multilateral pathways. Better understanding of the clinical research progress of small molecule inhibitors of potential targets of tumor metabolism will help to explore more effective cancer treatment strategies.

Lactate as Key Metabolite in Prostate Cancer Progression: What Are the Clinical Implications?

Advanced prostate cancer represents the fifth leading cause of cancer death in men worldwide. Although androgen-receptor signaling is the major driver of the disease, evidence is accumulating that disease progression is supported by substantial metabolic changes. Alterations in de novo lipogenesis and fatty acid catabolism are consistently reported during prostate cancer development and progression in association with androgen-receptor signaling. Therefore, the term "lipogenic phenotype" is frequently used to describe the complex metabolic rewiring that occurs in prostate cancer. However, a new scenario has emerged in which lactate may play a major role. Alterations in oncogenes/tumor suppressors, androgen signaling, hypoxic conditions, and cells in the tumor microenvironment can promote aerobic glycolysis in prostate cancer cells and the release of lactate in the tumor microenvironment, favoring immune evasion and metastasis. As prostate cancer is composed of metabolically heterogenous cells, glycolytic prostate cancer cells or cancer-associated fibroblasts can also secrete lactate and create "symbiotic" interactions with oxidative prostate cancer cells via lactate shuttling to sustain disease progression. Here, we discuss the multifaceted role of lactate in prostate cancer progression, taking into account the influence of the systemic metabolic and gut microbiota. We call special attention to the clinical opportunities of imaging lactate accumulation for patient stratification and targeting lactate metabolism.

DoubleSG-DTA: Deep Learning for Drug Discovery: Case Study on the Non-Small Cell Lung Cancer with EGFRT790M Mutation

Drug-targeted therapies are promising approaches to treating tumors, and research on receptor-ligand interactions for discovering high-affinity targeted drugs has been accelerating drug development. This study presents a mechanism-driven deep learning-based computational model to learn double drug sequences, protein sequences, and drug graphs to project drug-target affinities (DTAs), which was termed the DoubleSG-DTA. We deployed lightweight graph isomorphism networks to aggregate drug graph representations and discriminate between molecular structures, and stacked multilayer squeeze-and-excitation networks to selectively enhance spatial features of drug and protein sequences. What is more, cross-multi-head attentions were constructed to further model the non-covalent molecular docking behavior. The multiple cross-validation experimental evaluations on various datasets indicated that DoubleSG-DTA consistently outperformed all previously reported works. To showcase the value of DoubleSG-DTA, we applied it to generate promising hit compounds of Non-Small Cell Lung Cancer harboring EGFRT790M mutation from natural products, which were consistent with reported laboratory studies. Afterward, we further investigated the interpretability of the graph-based "black box" model and highlighted the active structures that contributed the most. DoubleSG-DTA thus provides a powerful and interpretable framework that extrapolates for potential chemicals to modulate the systemic response to disease.

Tumor lactic acid: a potential target for cancer therapy

Tumor development is influenced by circulating metabolites and most tumors are exposed to substantially elevated levels of lactic acid and low levels of nutrients, such as glucose and glutamine. Tumor-derived lactic acid, the major circulating carbon metabolite, regulates energy metabolism and cancer cell signaling pathways, while also acting as an energy source and signaling molecule. Recent studies have yielded new insights into the pro-tumorigenic action of lactic acid and its metabolism. These insights suggest an anti-tumor therapeutic strategy targeting the oncometabolite lactic acid, with the aim of improving the efficacy and clinical safety of tumor metabolism inhibitors. This review describes the current understanding of the multifunctional roles of tumor lactic acid, as well as therapeutic approaches targeting lactic acid metabolism, including lactate dehydrogenase and monocarboxylate transporters, for anti-cancer therapy.

Bcl-2 pathway inhibition in solid tumors: a review of clinical trials

Due to their key role in the pathogenesis of cancer through the regulation of apoptosis, the B-cell leukemia/lymphoma-2 (BCL-2) family proteins have been an attractive target for cancer therapy for the past decades. Throughout the years, many Bcl-2 family inhibitors have been developed, with Venetoclax being now successfully used in treating hematological malignancies. Although their effectiveness in the treatment of solid tumors is yet to be established, some preclinical evidence indicates their possible clinical application. This review aims to summarize current data from completed clinical trials that used Bcl-2 protein family inhibitors as monotherapy or in combination with other agents for the treatment of solid malignancies. We managed to include clinical trials of various phases which analyze the pharmacokinetics and pharmacodynamics of the drugs, as well as the effectiveness and adverse effects. Active and recruiting clinical trials are also briefly presented and future prospects and challenges are discussed.

Gossypol and Its Natural Derivatives: Multitargeted Phytochemicals as Potential Drug Candidates for Oncologic Diseases

Despite the vast amounts of research and remarkable discoveries that have been made in recent decades, cancer remains a leading cause of death and a major public health concern worldwide. Gossypol, a natural polyphenolic compound derived from the seeds, roots, and stems of cotton (Gossypium hirsutum L.), was first used as a male contraceptive agent. Due to its diverse biological properties, including antifertility, antiviral, antioxidant, antibacterial, antimalarial, and most notably antitumor activities, gossypol has been the subject of numerous studies. Nevertheless, no systematic review has been performed that analyzes the antineoplastic potential of gossypol and related natural compounds in an organ-specific manner while delineating the molecular mechanisms of action. Hence, we have performed an extensive literature search for anticancer properties of gossypol and their natural derivatives against various types of cancer cells utilizing PubMed, ScienceDirect, Google Scholar, and Scopus. The sources, distribution, chemical structure, and toxicity of gossypol and its constituents are briefly reviewed. Based on emerging evidence, gossypol and related compounds exhibit significant antineoplastic effects against various cancer types through the modulation of different cancer hallmarks and signaling pathways. Additionally, the synergistic activity of gossypol and its derivatives with chemotherapeutic agents has been observed. Our evaluation of the current literature suggests the potential of gossypol and its derivatives as multitargeting drug candidates to combat multiple human malignancies.

Warburg effect in colorectal cancer: the emerging roles in tumor microenvironment and therapeutic implications

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related death worldwide. Countless CRC patients undergo disease progression. As a hallmark of cancer, Warburg effect promotes cancer metastasis and remodels the tumor microenvironment, including promoting angiogenesis, immune suppression, cancer-associated fibroblasts formation and drug resistance. Targeting Warburg metabolism would be a promising method for the treatment of CRC. In this review, we summarize information about the roles of Warburg effect in tumor microenvironment to elucidate the mechanisms governing Warburg effect in CRC and to identify novel targets for therapy.

Metabolic changes during prostate cancer development and progression

Metabolic reprogramming has been recognised as a hallmark in solid tumours. Malignant modification of the tumour's bioenergetics provides energy for tumour growth and progression. Otto Warburg first reported these metabolic and biochemical changes in 1927. In prostate cancer (PCa) epithelial cells, the tumour metabolism also changes during development and progress. These alterations are partly driven by the androgen receptor, the key regulator in PCa development, progress, and survival. In contrast to other epithelial cells of different entities, glycolytic metabolism in prostate cells sustains physiological citrate secretion in the normal prostatic epithelium. In the early stages of PCa, citrate is utilised to power oxidative phosphorylation and fuel lipogenesis, enabling tumour growth and progression. In advanced and incurable castration-resistant PCa, a metabolic shift towards choline, amino acid, and glycolytic metabolism fueling tumour growth and progression has been described. Therefore, even if the metabolic changes are not fully understood, the altered metabolism during tumour progression may provide opportunities for novel therapeutic strategies, especially in advanced PCa stages. This review focuses on the main differences in PCa's metabolism during tumourigenesis and progression highlighting glutamine's role in PCa.

(-)-Gossypol enhances the anticancer activity of epirubicin via downregulating survivin in hepatocellular carcinoma

Epirubicin (EPI)-based transarterial chemoembolization is an effective therapy for advanced hepatocellular carcinoma (HCC). However, EPI-induced survivin expression limits its tumor-killing potential in HCC. Interestingly, (-)-gossypol ((-)-Gsp), a male contraceptive, suppresses various malignancies. More importantly, (-)-Gsp also holds promise for enhancing the antitumor effects of chemotherapy in numerous cancer types. In the present study, we demonstrated for the first time that (-)-Gsp-sensitized EPI inhibited cell growth and induced apoptosis of HCC cells in vitro. Furthermore, (-)-Gsp sensitized EPI by attenuating the EPI-elevated survivin protein levels. Mechanistic studies showed that EPI stimulated survivin protein synthesis by promoting translation initiation, which was alleviated by (-)-Gsp mainly through suppressing the AKT-4EBP1/p70S6K-survivin and ERK-4EBP1-survivin pathways. HCC xenograft experiments in nude mice also showed that (-)-Gsp treatment acted synergistically with EPI to repress xenograft tumor growth. Overall, our proof-of-concept results may pave the way for novel strategies for the treatment of HCC based on the combination of EPI and (-)-Gsp.

Historical perspective of tumor glycolysis: A century with Otto Warburg

Tumors have long been known to rewire their metabolism to endorse their proliferation, growth, survival, and invasiveness. One of the common characteristics of these alterations is the enhanced glucose uptake and its subsequent transformation into lactic acid by means of glycolysis, regardless the availability of oxygen or the mitochondria effectiveness. This phenomenon is called the "Warburg effect", which has turned into a century of age now, since its first disclosure by German physiologist Otto Heinrich Warburg. Since then, this peculiar metabolic switch in tumors has been addressed by extensive studies covering several areas of research. In this historical perspective, we aim at illustrating the evolution of these studies over time and their implication in various fields of science.

Preclinical Efficacy and Toxicity Analysis of the Pan-Histone Deacetylase Inhibitor Gossypol for the Therapy of Colorectal Cancer or Hepatocellular Carcinoma

Gossypol, a sesquiterpenoid found in cotton seeds, exerts anticancer effects on several tumor entities due to inhibition of DNA synthesis and other mechanisms. In clinical oncology, histone deacetylase inhibitors (HDACi) are applied as anticancer compounds. In this study, we examined whether gossypol harbors HDAC inhibiting activity. In vitro analyses showed that gossypol inhibited class I, II, and IV HDAC, displaying the capability to laterally interact with the respective catalytic center and is, therefore, classified as a pan-HDAC inhibitor. Next, we studied the effects of gossypol on human-derived hepatoma (HepG2) and colon carcinoma (HCT-116) cell lines and found that gossypol induced hyperacetylation of histone protein H3 and/or tubulin within 6 h. Furthermore, incubation with different concentrations of gossypol (5–50 µM) over a time period of 96 h led to a prominent reduction in cellular viability and proliferation of hepatoma (HepG2, Hep3B) and colon carcinoma (HCT-116, HT-29) cells. In-depth analysis of underlying mechanisms showed that gossypol induced apoptosis via caspase activation. For pre-clinical evaluation, toxicity analyses showed toxic effects of gossypol in vitro toward non-malignant primary hepatocytes (PHH), the colon-derived fibroblast cell line CCD-18Co, and the intestinal epithelial cell line CCD 841 CoN at concentrations of ≥5 µM, and embryotoxicity in chicken embryos at ≥2.5 µM. In conclusion, the pronounced inhibitory capacity of gossypol on cancer cells was characterized, and pan-HDACi activity was detected in silico, in vitro, by inhibiting individual HDAC isoenzymes, and on protein level by determining histone acetylation. However, for clinical application, further chemical optimization is required to decrease cellular toxicity.