Naturally derived indole alkaloids targeting regulated cell death (RCD) for cancer therapy: from molecular mechanisms to potential therapeutic targets

What is the role of microbial biotechnology and genetic engineering in medicine?

Microbial products are essential for developing various therapeutic agents, including antibiotics, anticancer drugs, vaccines, and therapeutic enzymes. Genetic engineering techniques, functional genomics, and synthetic biology unlock previously uncharacterized natural products. This review highlights major advances in microbial biotechnology, focusing on gene-based technologies for medical applications.

Exploiting Nanotechnology for Drug Delivery: Advancing the Anti-Cancer Effects of Autophagy-Modulating Compounds in Traditional Chinese Medicine

Background

Cancer continues to be a prominent issue in the field of medicine, as demonstrated by recent studies emphasizing the significant role of autophagy in the development of cancer. Traditional Chinese Medicine (TCM) provides a variety of anti-tumor agents capable of regulating autophagy. However, the clinical application of autophagy-modulating compounds derived from TCM is impeded by their restricted water solubility and bioavailability. To overcome this challenge, the utilization of nanotechnology has been suggested as a potential solution. Nonetheless, the current body of literature on nanoparticles delivering TCM-derived autophagy-modulating anti-tumor compounds for cancer treatment is limited, lacking comprehensive summaries and detailed descriptions.

Methods

Up to November 2023, a comprehensive research study was conducted to gather relevant data using a variety of databases, including PubMed, ScienceDirect, Springer Link, Web of Science, and CNKI. The keywords utilized in this investigation included "autophagy", "nanoparticles", "traditional Chinese medicine" and "anticancer".

Results

This review provides a comprehensive analysis of the potential of nanotechnology in overcoming delivery challenges and enhancing the anti-cancer properties of autophagy-modulating compounds in TCM. The evaluation is based on a synthesis of different classes of autophagy-modulating compounds in TCM, their mechanisms of action in cancer treatment, and their potential benefits as reported in various scholarly sources. The findings indicate that nanotechnology shows potential in enhancing the availability of autophagy-modulating agents in TCM, thereby opening up a plethora of potential therapeutic avenues.

Conclusion

Nanotechnology has the potential to enhance the anti-tumor efficacy of autophagy-modulating compounds in traditional TCM, through regulation of autophagy.

Molecular characteristics and prognostic significances of lysosomal-dependent cell death in kidney renal clear cell carcinoma

Lysosomal-dependent cell death (LDCD) has an excellent therapeutic effect on apoptosis-resistant and drug-resistant tumors; however, the important role of LDCD-related genes (LDCD-RGs) in kidney renal clear cell carcinoma (KIRC) has not been reported. Initially, single-cell atlas of LDCD signal in KIRC was comprehensively depicted. We also emphasized the molecular characteristics of LDCD-RGs in various human neoplasms. Predicated upon the expressive quotients of LDCD-RGs, we stratified KIRC patients into tripartite cohorts denoted as C1, C2, and C3. Those allocated to the ambit of C1 evinced the most sanguine prognosis within the KIRC cohort, underscored by the acme of LDCD-RGs scores. This further confirms the significant role that LDCD-RGs play in both the pathophysiological foundation and clinical implications of KIRC. In culmination, by virtue of employing the LASSO-Cox analytical modality, we have ushered in an innovative and avant-garde prognostic framework tailored for KIRC, predicated on the bedrock of LDCD-RGs. The assemblage of KIRC instances was arbitrarily apportioned into constituents inclusive of a didactic cohort, an internally wielded validation cadre, and an externally administered validation cohort. Concurrently, patients were dichotomized into strata connoting elevated jeopardy synonymous with adverse prognostic trajectories, and conversely, diminished risk tantamount to favorable prognoses, contingent on the calibrated expressions of LDCD-RGs. Succinctly, our investigative findings serve to underscore the cardinal capacity harbored by LDCD-RGs within the KIRC milieu, concurrently birthing a pioneering prognostic schema intrinsically linked to the trajectory of KIRC and its attendant prognoses.

Dysregulated CREB3 cleavage at the nuclear membrane induces karyoptosis-mediated cell death

Cancer cells often exhibit resistance to apoptotic cell death, but they may be vulnerable to other types of cell death. Elucidating additional mechanisms that govern cancer cell death is crucial for developing new therapies. Our research identified cyclic AMP-responsive element-binding protein 3 (CREB3) as a crucial regulator and initiator of a unique cell death mechanism known as karyoptosis. This process is characterized by nuclear shrinkage, deformation, and the loss of nuclear components following nuclear membrane rupture. We found that the N-terminal domain (aa 1-230) of full-length CREB3 (CREB3-FL), which is anchored to the nuclear inner membrane (INM), interacts with lamins and chromatin DNA. This interaction maintains a balance between the outward force exerted by tightly packed DNA and the inward constraining force, thereby preserving INM integrity. Under endoplasmic reticulum (ER) stress, aberrant cleavage of CREB3-FL at the INM leads to abnormal accumulation of the cleaved form of CREB3 (CREB3-CF). This accumulation disrupts the attachment of CREB3-FL to the INM, resulting in sudden rupture of the nuclear membrane and the onset of karyoptosis. Proteomic studies revealed that CREB3-CF overexpression induces a DNA damage response akin to that caused by UVB irradiation, which is associated with cellular senescence in cancer cells. These findings demonstrated that the dysregulation of CREB3-FL cleavage is a key factor in karyoptotic cell death. Consequently, these findings suggest new therapeutic strategies in cancer treatment that exploit the process of karyoptosis.

Ferroptosis and tumor immunity: In perspective of the major cell components in the tumor microenvironment

Ferroptosis is an iron-dependent form of cell death driven by lipid peroxidation, which is morphologically, biochemically, and genetically distinct from apoptosis, necrosis, and autophagy. Mounting studies on the essential role of ferroptosis have been published in the progression of solid tumors, metastasis, therapy, and therapy resistance. Studies showed that ferroptosis is a "double-edged sword" in tumor immunity, which means it may have both tumor-antagonizing and tumor-promoting functions. The tumor microenvironment (TME) comprises not only tumor cells but also surrounding immune cells, stromal cells, as well as noncellular components such as the extracellular matrix (ECM), cytokines, growth factors, and extracellular vesicles (EVs). In the complex and diverse condition in TME where tumor cells grow, changes in each constituent may impact tumor destiny differently. Recently, several studies have revealed the interaction between ferroptosis and different constituents in TME. Both tumor cells and nontumor cells have a dual role in tumor immunity and influence tumor progression through ferroptosis. Herein, this review aims at summarizing the role of ferroptosis in tumor immunity based on TME, focusing on the mechanisms of the interaction between the ferroptosis and the different constituents in TME, illuminating how ferroptosis plays its role in promoting or antagonizing tumors by acting with varying components in TME and proposing several questions in immunomodulatory effects of ferroptosis and ferroptosis-associated immunotherapy.

Metabolic changes preceding bladder cancer occurrence among Korean men: a nested case-control study from the KCPS-II cohort

BACKGROUND

Bladder cancer (BLCA) research in Koreans is still lacking, especially in focusing on the prediction of BLCA. The current study aimed to discover metabolic signatures related to BLCA onset and confirm its potential as a biomarker.

METHODS

We designed two nested case-control studies using Korean Cancer Prevention Study (KCPS)-II. Only males aged 35-69 were randomly selected and divided into two sets by recruitment organizations [set 1, BLCA (n = 35) vs. control (n = 35); set 2, BLCA (n = 31) vs. control (n = 31)]. Baseline serum samples were analyzed by non-targeted metabolomics profiling, and OPLS-DA and network analysis were performed. Calculated genetic risk score (GRS) for BLCA from all KCPS participants was utilized for interpreting metabolomics data.

RESULTS

Critical metabolic signatures shown in the BLCA group were dysregulation of lysine metabolism and tryptophan-indole metabolism. Furthermore, the prediction model consisting of metabolites (lysine, tryptophan, indole, indoleacrylic acid, and indoleacetaldehyde) reflecting these metabolic signatures showed mighty BLCA predictive power (AUC: 0.959 [0.929-0.989]). The results of metabolic differences between GRS-high and GRS-low groups in BLCA indicated that the pathogenesis of BLCA is associated with a genetic predisposition. Besides, the predictive ability for BLCA on the model using GRS and five significant metabolites was powerful (AUC: 0.990 [0.980-1.000]).

CONCLUSION

Metabolic signatures shown in the present research may be closely associated with BLCA pathogenesis. Metabolites involved in these could be predictive biomarkers for BLCA. It could be utilized for early diagnosis, prognostic diagnosis, and therapeutic targets for BLCA.

Nutritional properties of giant water bug, Lethocerus indicus a traditional edible insect species of North-East India

Edible insects play an important role in human health and food security. Among those, the Giant water bug, Lethocerus indicus (Lep.& Ser.) is a widely used edible insect known for its aroma, flavor, and therapeutic purposes. In the present study, we investigated the nutritional profile, natural habitat, and feeding behavior of L. indicus in aquarium conditions. A comparative analysis of male and female insects' aroma contents and fatty acid (FA) profiles was also conducted. A dry fried male insect yielded volatile oil of 0.96%/2 g body weight, whereas a dry fried female yielded 0.48%/5.36 g of body weight. In terms of lipids, fresh male insects had 0.15%/5.42 g of body weight and fresh female insects had 0.28%/9.48 g of body weight. There are 24 volatile compounds specific to males, 37 specific to females, and 13 commons to both were identified. 2-Hexen-1-ol, acetate, (Z)- which smells like banana, was prevalently found in males while 4-Octene, 2,6-dimethyl-, [S-(Z)] was prevalently found in female insects. Fatty acids profile analysis detected 32 FA with 12 unique FA from males whereas 22 FA and 3 unique FA were identified from female insects. The SFA percentage present in males and females was 77.44% and 85.21%. Males had 6.78% MUFA content while females have 4.75%. Males have 18% PUFA content enriched with DHA, and EPA, while females had 10.04%. This study revealed that with the presence of a banana-like smell of volatile compound and more MUFA and PUFA in males, the native people of North-East India preferred male over female insects for entomophagy.

Oncoviruses: Induction of cancer development and metastasis by increasing anoikis resistance

The phenomenon of cell death is a vital aspect in the regulation of aberrant cells such as cancer cells. Anoikis is a kind of cell death that occurs when cells get separated from the extracellular matrix. Some cancer cells can inhibit anoikis in order to progress metastasis. One of the key variables that might be implicated in anoikis resistance (AR) is viral infections. The most important viruses involved in this process are Epstein-Barr virus, human papillomavirus, hepatitis B virus, human herpes virus 8, human T-cell lymphotropic virus type 1, and hepatitis C virus. A better understanding of how carcinogenic viruses suppress anoikis might be helpful in developing an effective treatment for virus-associated cancers. In the current study, we review the role of the mentioned viruses and their gene products in anoikis inhibition.

Research Progress of Indole Alkaloids: Targeting MAP Kinase Signaling Pathways in Cancer Treatment

Cancer is the leading cause of morbidity and mortality in people throughout the world. There are many signaling pathways associated with cancerous diseases, from which the Mitogen-activated protein kinase (MAPK) pathway performs a significant role in this regard. Apoptosis and proliferation are correlated with MAPK signaling pathways. Plenty of experimental investigations were carried out to assess the role of indole alkaloids in MAPK-mediated cancerous diseases. Previous reports established that indole alkaloids, such as vincristine and evodiamine are useful small molecules in cancer treatment via the MAPK signaling system. Indole alkaloids have the anticancer potential through different pathways. Vincristine and evodiamine are naturally occurring indole alkaloids that have strong anticancer properties. Additionally, much research is ongoing or completed with molecules belonging to this group. The current review aims to evaluate how indole alkaloids affect the MAPK signaling pathway in cancer treatment. Additionally, we focused on the advancement in the role of indole alkaloids, with the intention of modifying the MAPK signaling pathways to investigate potential new anticancer small molecules. Furthermore, clinical trials with indole alkaloids in cancer treatment are also highlighted.

Vincamine, from an antioxidant and a cerebral vasodilator to its anticancer potential

Vincamine is a naturally occurring indole alkaloid showing antioxidant activity and has been used clinically for the prevention and treatment of cerebrovascular disorders and insufficiencies. It has been well documented that antioxidants may contribute to cancer treatment, and thus, vincamine has been investigated recently for its potential antitumor activity. Vincamine was found to show cancer cell cytotoxicity and to modulate several important proteins involved in tumor growth, including acetylcholinesterase (AChE), mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), and T-box 3 (TBX3). Several bisindole alkaloids, including vinblastine and vincristine and their synthetic derivatives, vindesine, vinflunine, and vinorelbine, have been used as clinically effective cancer chemotherapeutic agents. In the present review, the discovery and development of vincamine as a useful therapeutic agent and its antioxidant and antitumor activity are summarized, with its antioxidant-related mechanisms of anticancer potential being described. Also, discussed herein are the design of the potential vincamine-based oncolytic agents, which could contribute to the discovery of further new agents for cancer treatment.

Recent advances in targeting the "undruggable" proteins: from drug discovery to clinical trials

Undruggable proteins are a class of proteins that are often characterized by large, complex structures or functions that are difficult to interfere with using conventional drug design strategies. Targeting such undruggable targets has been considered also a great opportunity for treatment of human diseases and has attracted substantial efforts in the field of medicine. Therefore, in this review, we focus on the recent development of drug discovery targeting "undruggable" proteins and their application in clinic. To make this review well organized, we discuss the design strategies targeting the undruggable proteins, including covalent regulation, allosteric inhibition, protein-protein/DNA interaction inhibition, targeted proteins regulation, nucleic acid-based approach, immunotherapy and others.

Paeonol repurposing for cancer therapy: From mechanism to clinical translation

Paeonol (PAE) is a natural phenolic monomer isolated from the root bark of Paeonia suffruticosa that has been widely used in the clinical treatment of some inflammatory-related diseases and cardiovascular diseases. Much preclinical evidence has demonstrated that PAE not only exhibits a broad spectrum of anticancer effects by inhibiting cell proliferation, invasion and migration and inducing cell apoptosis and cycle arrest through multiple molecular pathways, but also shows excellent performance in improving cancer drug sensitivity, reversing chemoresistance and reducing the toxic side effects of anticancer drugs. However, studies indicate that PAE has the characteristics of poor stability, low bioavailability and short half-life, which makes the effective dose of PAE in many cancers usually high and greatly limits its clinical translation. Fortunately, nanomaterials and derivatives are being developed to ameliorate PAE's shortcomings. This review aims to systematically cover the anticancer advances of PAE in pharmacology, pharmacokinetics, nano delivery systems and derivatives, to provide researchers with the latest and comprehensive information, and to point out the limitations of current studies and areas that need to be strengthened in future studies. We believe this work will be beneficial for further exploration and repurposing of this natural compound as a new clinical anticancer drug.

Recent advances in targeted strategies for triple-negative breast cancer

Triple-negative breast cancer (TNBC), a highly aggressive subtype of breast cancer, negatively expresses estrogen receptor, progesterone receptor, and the human epidermal growth factor receptor 2 (HER2). Although chemotherapy is the main form of treatment for patients with TNBC, the effectiveness of chemotherapy for TNBC is still limited. The search for more effective therapies is urgent. Multiple targeted therapeutic strategies have emerged according to the specific molecules and signaling pathways expressed in TNBC. These include PI3K/AKT/mTOR inhibitors, epidermal growth factor receptor inhibitors, Notch inhibitors, poly ADP-ribose polymerase inhibitors, and antibody-drug conjugates. Moreover, immune checkpoint inhibitors, for example, pembrolizumab, atezolizumab, and durvalumab, are widely explored in the clinic. We summarize recent advances in targeted therapy and immunotherapy in TNBC, with the aim of serving as a reference for the development of individualized treatment of patients with TNBC in the future.

Ferroptosis: a novel regulated cell death participating in cellular stress response, radiotherapy, and immunotherapy

BACKGROUND

Ferroptosis is a regulated cell death mode triggered by iron-dependent toxic membrane lipid peroxidation. As a novel cell death modality that is morphologically and mechanistically different from other forms of cell death, such as apoptosis and necrosis, ferroptosis has attracted extensive attention due to its association with various diseases. Evidence on ferroptosis as a potential therapeutic strategy has accumulated with the rapid growth of research on targeting ferroptosis for tumor suppression in recent years.

METHODS

We summarize the currently known characteristics and major regulatory mechanisms of ferroptosis and present the role of ferroptosis in cellular stress responses, including ER stress and autophagy. Furthermore, we elucidate the potential applications of ferroptosis in radiotherapy and immunotherapy, which will be beneficial in exploring new strategies for clinical tumor treatment.

RESULT AND CONCLUSION

Based on specific biomarkers and precise patient-specific assessment, targeting ferroptosis has great potential to be translated into practical new approaches for clinical cancer therapy, significantly contributing to the prevention, diagnosis, prognosis, and treatment of cancer.

A metabologenomics approach to unlock the metabolome of the novel Antarctic deep-sea isolate Lacinutrix shetlandiensis sp. nov. WUR7

The South Shetland Trough, Antarctica, is an underexplored region for microbiological and biotechnological exploitation. Herein, we describe the isolation and characterization of the novel bacterium Lacinutrix shetlandiensis sp. nov. WUR7 from a deep-sea environment. We explored its chemical diversity via a metabologenomics approach, wherein the OSMAC strategy was strategically employed to upregulate cryptic genes for secondary metabolite production. Based on hybrid de novo whole genome sequencing and digital DNA-DNA hybridization, isolate WUR7 was identified as a novel species from the Gram-negative genus Lacinutrix. Its genome was mined for the presence of biosynthetic gene clusters with limited results. However, extensive investigation of its metabolism uncovered an unusual tryptophan decarboxylase with high sequence homology and conserved structure of the active site as compared to ZP_02040762, a highly specific tryptophan decarboxylase from Ruminococcus gnavus. Therefore, WUR7's metabolism was directed toward indole-based alkaloid biosynthesis by feeding it with L-tryptophan. As expected, its metabolome profile changed dramatically, by triggering the extracellular accumulation of a massive array of metabolites unexpressed in the absence of tryptophan. Untargeted LC-MS/MS coupled with molecular networking, followed along with chemoinformatic dereplication, allowed for the annotation of 10 indole alkaloids, belonging to β-carboline, bisindole, and monoindole classes, alongside several unknown alkaloids. These findings guided us to the isolation of a new natural bisindole alkaloid 8,9-dihydrocoscinamide B (1), as the first alkaloid from the genus Lacinutrix, whose structure was elucidated on the basis of extensive 1D and 2D NMR and HR-ESIMS experiments. This comprehensive strategy allowed us to unlock the previously unexploited metabolome of L. shetlandiensis sp. nov. WUR7.

Natural products targeting signaling pathways associated with regulated cell death in gastric cancer: Recent advances and perspectives

Gastric cancer (GC) is one of the most serious gastrointestinal malignancies with high morbidity and mortality. The complexity of GC process lies in the multi-phenotypic linkage regulation, in which regulatory cell death (RCD) is the core link, which largely dominates the fate of GC cells and becomes a key determinant of GC development and prognosis. In recent years, increasing evidence has been reported that natural products can prevent and inhibit the development of GC by regulating RCDs, showing great therapeutic potential. In order to further clarify its key regulatory characteristics, this review focused on specific expressions of RCDs, combined with a variety of signaling pathways and their crosstalk characteristics, sorted out the key targets and action rules of natural products targeting RCD. It is highlighted that a variety of core biological pathways and core targets are involved in the decision of GC cell fate, including the PI3K/Akt signaling pathway, MAPK-related signaling pathways, p53 signaling pathway, ER stress, Caspase-8, gasdermin D (GSDMD), and so on. Moreover, natural products target the crosstalk of different RCDs by modulating above signaling pathways. Taken together, these findings suggest that targeting various RCDs in GC with natural products is a promising strategy, providing a reference for further clarifying the molecular mechanism of natural products treating GC, which warrants further investigations in this area.

The Protective Effect of (-)-Tetrahydroalstonine against OGD/R-Induced Neuronal Injury via Autophagy Regulation

Here, (-)-Tetrahydroalstonine (THA) was isolated from Alstonia scholaris and investigated for its neuroprotective effect towards oxygen-glucose deprivation/re-oxygenation (OGD/R)-induced neuronal damage. In this study, primary cortical neurons were pre-treated with THA and then subjected to OGD/R induction. The cell viability was tested by the MTT assay, and the states of the autophagy-lysosomal pathway and Akt/mTOR pathway were monitored by Western blot analysis. The findings suggested that THA administration increased the cell viability of OGD/R-induced cortical neurons. Autophagic activity and lysosomal dysfunction were found at the early stage of OGD/R, which were significantly ameliorated by THA treatment. Meanwhile, the protective effect of THA was significantly reversed by the lysosome inhibitor. Additionally, THA significantly activated the Akt/mTOR pathway, which was suppressed after OGD/R induction. In summary, THA exhibited promising protective effects against OGD/R-induced neuronal injury by autophagy regulation through the Akt/mTOR pathway.

Recent Advances on Direct Functionalization of Indoles in Aqueous Media

Indoles and their derivatives have dominated a significant proportion of nitrogen-containing heterocyclic compounds and play an essential role in synthetic and medicinal chemistry, pesticides, and advanced materials. Compared with conventional synthetic strategies, direct functionalization of indoles provides straightforward access to construct diverse indole scaffolds. As we enter an era emphasizing green and sustainable chemistry, utilizing environment-friendly solvents represented by water demonstrates great potential in synthesizing valuable indole derivatives. This review aims to depict the critical aspects of aqueous-mediated indoles functionalization over the past decade and discusses the future challenges and prospects in this fast-growing field. For the convenience of readers, this review is classified into three parts according to the bonding modes (C-C, C-N, and C-S bonds), which focus on the diversity of indole derivatives, the prominent role of water in the chemical process, and the types of catalyst systems and mechanisms. We hope this review can promote the sustainable development of the direct functionalization of indoles and their derivatives and the discovery of novel and practical organic methods in aqueous phase.

Callyspongia spp.: Secondary Metabolites, Pharmacological Activities, and Mechanisms

One of the most widespread biotas in the sea is the sponge. Callyspongia is a sponge genus found in the seas, making it easily available. In this review, the pharmacological activity and mechanism of action of the secondary metabolites of Callyspongia spp. are addressed, which may lead to the development of new drugs and targeted therapeutic approaches. Several scientific databases, such as Google Scholar, PubMed, ResearchGate, Science Direct, Springer Link, and Wiley Online Library, were mined to obtain relevant information. In the 41 articles reviewed, Callyspongia spp. was reported to possess pharmacological activities such as cytotoxicity against cancer cell lines (36%), antifungal (10%), anti-inflammatory (10%), immunomodulatory (10%), antidiabetic and antiobesity (6%), antimicrobial (8%), antioxidant (4%), antineurodegenerative (4%), antihypercholesterolemic (2%), antihypertensive (2%), antiparasitic (2%), antiallergic (2%), antiviral (2%), antiosteoporotic (2%), and antituberculosis (2%) activities. Of these, the antioxidant, antituberculosis, and anti-inflammatory activities of Callyspongia extract were weaker compared with that of the control drugs; however, other activities, particularly cytotoxicity, show promise, and the compounds responsible may be developed into new drugs.