Targeting cell cycle by β-carboline alkaloids in vitro: Novel therapeutic prospects for the treatment of cancer

The Emerging Role of Natural Products in Cancer Treatment

The exploration of natural products as potential agents for cancer treatment has garnered significant attention in recent years. In this comprehensive review, we delve into the diverse array of natural compounds, including alkaloids, carbohydrates, flavonoids, lignans, polyketides, saponins, tannins, and terpenoids, highlighting their emerging roles in cancer therapy. These compounds, derived from various botanical sources, exhibit a wide range of mechanisms of action, targeting critical pathways involved in cancer progression such as cell proliferation, apoptosis, angiogenesis, and metastasis. Through a meticulous examination of preclinical and clinical studies, we provide insights into the therapeutic potential of these natural products across different cancer types. Furthermore, we discuss the advantages and challenges associated with their use in cancer treatment, emphasizing the need for further research to optimize their efficacy, pharmacokinetics, and delivery methods. Overall, this review underscores the importance of natural products in advancing cancer therapeutics and paves the way for future investigations into their clinical applications.

In Vitro Effect of 9,9'-Norharmane Dimer against Herpes Simplex Viruses

Herpes simplex virus (HSV) infections are highly widespread among humans, producing symptoms ranging from ulcerative lesions to severe diseases such as blindness and life-threatening encephalitis. At present, there are no vaccines available, and some existing antiviral treatments can be ineffective or lead to adverse effects. As a result, there is a need for new anti-HSV drugs. In this report, the in vitro anti-HSV effect of 9,9'-norharmane dimer (nHo-dimer), which belongs to the β-carboline (βC) alkaloid family, was evaluated. The dimer exhibited no virucidal properties and did not impede either the attachment or penetration steps of viral particles. The antiviral effect was only exerted under the constant presence of the dimer in the incubation media, and the mechanism of action was found to involve later events of virus infection. Analysis of fluorescence lifetime imaging data showed that the nHo-dimer internalized well into the cells when present in the extracellular incubation medium, with a preferential accumulation into perinuclear organelles including mitochondria. After washing the host cells with fresh medium free of nHo-dimer, the signal decreased, suggesting the partial release of the compound from the cells. This agrees with the observation that the antiviral effect is solely manifested when the alkaloid is consistently present in the incubation media.

Construction of a prognostic model based on memory CD4+ T cell-associated genes for lung adenocarcinoma and its applications in immunotherapy

The association between memory CD4+ T cells and cancer prognosis is increasingly recognized, but their impact on lung adenocarcinoma (LUAD) prognosis remains unclear. In this study, using the cell-type identification by estimating relative subsets of RNA transcripts algorithm, we analyzed immune cell composition and patient survival in LUAD. Weighted gene coexpression network analysis helped identify memory CD4+ T cell-associated gene modules. Combined with module genes, a five-gene LUAD prognostic risk model (HOXB7, MELTF, ABCC2, GNPNAT1, and LDHA) was constructed by regression analysis. The model was validated using the GSE31210 data set. The validation results demonstrated excellent predictive performance of the risk scoring model. Correlation analysis was conducted between the clinical information and risk scores of LUAD samples, revealing that LUAD patients with disease progression exhibited higher risk scores. Furthermore, univariate and multivariate regression analyses demonstrated the model independent prognostic capability. The constructed nomogram results demonstrated that the predictive performance of the nomogram was superior to the prognostic model and outperformed individual clinical factors. Immune landscape assessment was performed to compare different risk score groups. The results revealed a better prognosis in the low-risk group with higher immune infiltration. The low-risk group also showed potential benefits from immunotherapy. Our study proposes a memory CD4+ T cell-associated gene risk model as a reliable prognostic biomarker for personalized treatment in LUAD patients.

Liensinine reduces acute lung injury brought on by lipopolysaccharide by inhibiting the activation of the NF-κB signaling pathway through modification of the Src/TRAF6/TAK1 axis

ALI is characterized by macrophage-driven inflammation, causing severe lung damage. Currently, there are limited therapeutic options available for ALI. Liensinine (LIEN), with known anti-inflammatory properties, lacks extensive study in the ALI context. This study aimed to investigate the impact of LIEN on ALI and elucidate its molecular mechanisms. A total of thirty-six male BALB/c mice altogether were split into six groups: Control, LPS (10 mg/kg), Low (10 mg/kg LIEN + 10 mg/kg LPS), Middle (20 mg/kg LIEN + 10 mg/kg LPS), High (40 mg/kg LIEN + 10 mg/kg LPS), and DEX (2 mg/kg DEX + 10 mg/kg LPS). Lung tissue injury, pulmonary edema, and inflammatory factor levels were evaluated in lung tissues and LPS-stimulated bone marrow-derived macrophages (BMDM). TAK1 activation, TRAF6 ubiquitination, and their interactions were assessed to understand the involved molecular mechanisms. LIEN treatment ameliorated lung tissue injury and suppressed LPS-induced inflammatory factor levels in lung tissues and BMDM. Mechanistically, LIEN inhibited TAK1 activation by disrupting TRAF6-TAK1 interactions, limiting p65's nuclear translocation, and reducing the release of inflammatory factors. According to network pharmacology and molecular docking, LIEN most likely prevents inflammation by interfering directly with the Src. Overexpression of Src in BMDM abolished the regulation of TRAF6 by LIEN, supporting the involvement of the Src/TRAF6/TAK1 axis in its mechanism of action. Based on this study, LIEN treats ALI by modifying the Src/TRAF6/TAK1 axis and blocking the activation of the NF-κB pathway, regulating the release of inflammatory factors. These findings highlight the promise of LIEN as a prospective therapeutic option for the treatment of ALI.

Anticancer mechanisms of β-carbolines

β-Carboline nucleus is therapeutically valuable in medicinal chemistry for the treatment of varied number of diseases, most importantly cancer. The potent and wide-ranging activity of β-carboline has established them as imperative pharmacological scaffolds especially in the cancer treatment. Numerous derivatives such as Tetrahydro β-carbolines, metal complexed β-carbolines, mono, di and tri substituted β-carbolines have been reported to possess dynamic anticancer activity. These different substituted β-carboline derivatives had shown different mechanism of action and plays important role in anticancer drug discovery and development. The review is an update of the chemistry of β-carbolines, both synthetic and natural origin acting through various targets against cancerous cells. In addition to this, studies of multitarget molecules designed by coupling β-carbolines along with other mechanisms for treatment of neoplasm are also summarized.

The β-Carboline Harmine Has a Protective Immunomodulatory Role in Nonhealing Cutaneous Leishmaniasis

Cutaneous leishmaniasis affects 1 million people worldwide annually. Although conventional treatments primarily target the parasite, there is growing interest in host immune modulation. In this study, we investigated the impact of synthetic β-carboline harmine (ACB1801), previously shown to be immunoregulatory in cancer, on the pathology caused by a drug-resistant Leishmania major strain causing persistent cutaneous lesions. Exposure to ACB1801 in vitro had a modest impact on parasite burden within host macrophages. Moreover, it significantly increased major histocompatibility complex II and costimulatory molecule expression on infected dendritic cells, suggesting an enhanced immune response. In vivo, ACB1801 monotherapy led to a substantial reduction in lesion development and parasite burden in infected C57BL/6 mice, comparable with efficacy of amphotericin B. Transcriptomics analysis further supported ACB1801 immunomodulatory effects, revealing an enrichment of TNF-α, IFN-γ, and major histocompatibility complex II antigen presentation signatures in the draining lymph nodes of treated mice. Flow cytometry analysis confirmed an increased frequency (1.5×) of protective CD4+IFN-γ+TNF-α+ T cells and a decreased frequency (2×) in suppressive IL-10+FoxP3- T cells at the site of infection and in draining lymph nodes. In addition, ACB1801 downregulated the aryl hydrocarbon receptor signaling, known to enhance immunosuppressive cytokines. Thus, these results suggest a potential use for ACB1801 alone or in combination therapy for cutaneous leishmaniasis.

Anticancer Potential of β-Carboline Alkaloids: An Updated Mechanistic Overview

his comprehensive review is designed to evaluate the anticancer properties of β-carbolines derived from medicinal plants, with the ultimate goal of assessing their suitability and potential in cancer treatment, management, and prevention. An exhaustive literature survey was conducted on a wide array of β-carbolines including, but not limited to, harmaline, harmine, harmicine, harman, harmol, harmalol, pinoline, tetrahydroharmine, tryptoline, cordysinin C, cordysinin D, norharmane, and perlolyrine. Various analytical techniques were employed to identify and screen these compounds, followed by a detailed analysis of their anticancer mechanisms. Natural β-carbolines such as harmaline and harmine have shown promising inhibitory effects on the growth of cancer cells, as evidenced by multiple in vitro and in vivo studies. Synthetically derived β-carbolines also displayed noteworthy anticancer, neuroprotective, and cognitive-enhancing effects. The current body of research emphasizes the potential of β-carbolines as a unique source of bioactive compounds for cancer treatment. The diverse range of β-carbolines derived from medicinal plants can offer valuable insights into the development of new therapeutic strategies for cancer management and prevention.

Design, synthesis, and biological evaluation of novel dihydropteridone derivatives possessing oxadiazoles moiety as potent inhibitors of PLK1

Polo like kinase 1 (PLK1) is a serine/threonine kinase that is widely distributed in eukaryotic cells and plays an important role in multiple phases of the cell cycle. Its importance in tumorigenesis has been increasingly recognized in recent years. Herein, we describe the optimization of a series of novel dihydropteridone derivatives (13a-13v and 21g-21l) possessing oxadiazoles moiety as potent inhibitors of PLK1. Compound 21g exhibited improved PLK1 inhibitory capability with an IC₅₀ value of 0.45 nM and significant anti-proliferative activities against four tumor-derived cell lines (MCF-7 IC₅₀ = 8.64 nM, HCT-116 IC₅₀ = 26.0 nM, MDA-MB-231 IC₅₀ = 14.8 nM and MV4-11 IC₅₀ = 47.4 nM) with better pharmacokinetic characteristics than BI2536 in mice (AUC_0-t = 11 227 ng h mL^-1vs 556 ng h mL^-1). Moreover, 21g exhibited moderate liver microsomal stability and excellent pharmacokinetic profile (AUC_0-t = 11227 ng h mL^-1, oral bioavailability of 77.4%) in Balb/c mice, acceptable PPB, improved PLK1 inhibitory selectivity, and no apparent toxicity was observed in the acute toxicity assay (20 mg/kg). Further investigation showed that 21 g could arrest HCT-116 cells in G2 phase and induce apoptosis in a dose-dependent manner. These results indicate that 21g is a promising PLK1 inhibitor.

Platycodin-D exerts its anti-cancer effect by promoting c-Myc protein ubiquitination and degradation in gastric cancer

Platycodin D (PD) is a triterpene saponin extracted from the root of Platycodon grandiflorum. It has been reported to exhibit multiple pharmacological and biological properties. There is substantial evidence to support that PD displays a wide range of anti-tumor activities. However, the detailed molecular mechanism still needs further elaboration. In the present study, to explore whether PD inhibits gastric cancer (GC) cell viability, eight GC cell lines and the GES-1 cell line (a gastric mucosal cell line) were tested. We found that PD exhibited better inhibitory activity on GC cell lines than on the non-tumor cell line. Besides, treatment with PD led to a significant cell cycle arrest, thereby causing subsequent apoptosis. Regarding the cell growth inhibition mechanism, PD can downregulate the protein level of c-Myc rather than its mRNA level in a dose-dependent manner. Further studies revealed that PD disturbed the overall ubiquitination level in GC cell lines and enhanced the ubiquitination-dependent degradation of c-Myc. Interestingly, the inhibition of cell viability by PD could be restored to a certain extent when the expression of c-Myc was recovered, suggesting that PD-mediated GC cell growth inhibition is closely associated with c-Myc expression. Our study proposes a novel molecular mechanism for PD inhibiting GC cell proliferation and growth by destabilizing the c-Myc protein. This work may lay a preliminary foundation for developing PD as an anti-cancer therapy.

Polo-like kinase 1 as a potential therapeutic target and prognostic factor for various human malignancies: A systematic review and meta-analysis

Objective

The overexpression of polo-like kinase 1 (PLK-1) has been found in a broad spectrum of human tumors, making it an attractive prognostic tumor biomarker. Nowadays, PLK-1 is considered a cancer therapeutic target with clinical therapeutic value. The aim of the present study was to systematically review the prognostic and therapeutic value of PLK-1 in different malignant neoplasms.

Methods

A systematic literature search of the Cochrane Library, PubMed, Web of Science, and China National Knowledge Internet (CNKI) databases was conducted between December 2018 and September 2022. In total, 41 published studies were screened, comprising 5,301 patients. We calculated the pooled odds ratios (ORs) and corresponding 95%CIs for the clinical parameters of patients included in these studies, as well as the pooled hazard ratios (HRs) and corresponding 95% CIs for 5-year overall survival (OS).

Results

Our analysis included 41 eligible studies, representing a total of 5,301 patients. The results showed that overexpression of PLK-1 was significantly associated with poor OS (HR, 1.57; 95% CI, 1.18–2.08) and inferior 5-year disease-free survival/relapse-free survival ((HR, 1.89; 95% CI, 1.47–2.44). The pooled analysis showed that PLK-1 overexpression was significantly associated with lymph node metastasis, histological grade, clinical stages (p < 0.001 respectively), and tumor grade (p < 0.001). In digestive system neoplasms, PLK-1 overexpression was significantly associated with histopathological classification, primary tumor grade, histological grade, and clinical stages (p = 0.002, p = 0.001, p < 0.0001, respectively). In breast cancer, PLK-1 was significantly associated with 5-year overall survival, histological grade, and lymph node metastasis (p < 0.001, p = 0.003, p < 0.001, respectively). In the female reproductive system, PLK-1 was significantly associated with clinical stage (p = 0.011). In the respiratory system, PLK-1 was significantly associated with clinical stage (p = 0.021).

Conclusion

Our analysis indicates that high PLK-1 expression is associated with aggressiveness and poor prognosis in malignant neoplasms. Therefore, PLK-1 may be a clinically valuable target for cancer treatment.

Natural products targeting glycolytic signaling pathways-an updated review on anti-cancer therapy

Glycolysis is a complex metabolic process that occurs to convert glucose into pyruvate to produce energy for living cells. Normal cells oxidized pyruvate into adenosine triphosphate and carbon dioxide in the presence of oxygen in mitochondria while cancer cells preferentially metabolize pyruvate to lactate even in the presence of oxygen in order to maintain a slightly acidic micro-environment of PH 6.5 and 6.9, which is beneficial for cancer cell growth and metastasis. Therefore targeting glycolytic signaling pathways provided new strategy for anti-cancer therapy. Natural products are important sources for the treatment of diseases with a variety of pharmacologic activities. Accumulated studies suggested that natural products exhibited remarkable anti-cancer properties both in vitro and in vivo. Plenty of studies suggested natural products like flavonoids, terpenoids and quinones played anti-cancer properties via inhibiting glucose metabolism targets in glycolytic pathways. This study provided an updated overview of natural products controlling glycolytic pathways, which also provide insight into druggable mediators discovery targeting cancer glucose metabolism.

β-Carboline dimers inhibit the tumor proliferation by the cell cycle arrest of sarcoma through intercalating to Cyclin-A2

β-Carbolines are potentially strong alkaloids with a wide range of bioactivities, and their dimers exhibit stronger antitumor activity other than the monomers. However, the detailed mechanisms of the β-carboline dimers in inhibiting sarcoma (SARC) remain unclear. The results showed that β-carboline-3-carboxylic acid dimers Comp1 and Comp2, which were synthesized in our lab and modified at the N⁹ position and linked at the C³ position, exhibited effective inhibition activity on MG-63 proliferation (IC_{50 =} 4.6μM). Meanwhile, the large scale transcriptome profiles of SARC from The Cancer Genome Atlas (TCGA) were analyzed, and found that abnormal expression of genes relevant to apoptosis, cell cycle, and signaling pathways of Hedgehog, HIF, Ras involved in the SARC pathogenesis. Interestingly, both dimers could promote the apoptosis and arrest the cell cycle in S phase to inhibit proliferation of MG-63. Moreover, Comp1 and Comp2 inhibited the expression CDK2, CCNA2, DBF4, and PLK1 associated with various immune cells and cell cycle in MG-63. Remarkably, drug-target interaction network analysis showed that numerous proteins involved in cell cycle were the potential targets of Comp1 and Comp2, especially CCNA2. Further molecular docking, isothermal titration calorimetry (ITC) and Cellular Thermal Shift Assay (CETSA) confirmed that both dimers could directly interact with CCNA2, which is significantly correlated with CD4+ T cells, by strong hydrophobic interactions (K_d=5.821 ×10⁶ N). Meanwhile, the levels of CCNA2 and CDK2 were inhibited to decrease in MG-63 by both dimer treatments at transcription and protein levels, implying that Comp1 and Comp2 blocked the interaction between CCNA2 and CDK2 through competitive binding with CCNA2 to arrest the cell cycle of MG-63 cells in the S phase. Additionally, the transcriptome profiles of β-carboline-treated mice from Gene Expression Omnibus (GEO) were obtained, and found that similar antitumor mechanism was shared among β-carboline derivatives. Overall, our results elucidated the antitumor mechanisms of Comp1 and Comp2 through dual-suppressing the function of CCNA2 to profoundly arrest cell cycle of MG-63, then effectively inhibited cell proliferation of MG-63. These results provide new insights into the antitumor mechanism of β-carboline dimers and new routes of various novel cancer-related drug targets for future possible cancer therapy.

Ursolic acid augments the chemosensitivity of drug-resistant breast cancer cells to doxorubicin by AMPK-mediated mitochondrial dysfunction

Multidrug resistance remains the major obstacle to successful therapy for breast carcinoma. Ursolic acid (UA), a triterpenoid compound, has been regarded as a potential neoplasm chemopreventive drug in some preclinical studies since it exerts multiple biological activities. In this research, we investigated the role of UA in augmenting the chemosensitivity of drug-resistant breast carcinoma cells to doxorubicin (DOX), and we further explored the possible molecular mechanisms. Notably, we found that UA treatment led to inhibition of cellular proliferation and migration and cell cycle arrest in DOX-resistant breast cancers. Furthermore, combination treatment with UA and DOX showed a stronger inhibitory effect on cell viability, colony formation, and cell migration; induced more cell apoptosis in vitro; and generated a more potent inhibitory effect on the growth of the MCF-7/ADR xenograft tumor model than DOX alone. Mechanistically, UA effectively increased p-AMPK levels and concomitantly reduced p-mTOR and PGC-1α protein levels, resulting in impaired mitochondrial function, such as mitochondrial respiration inhibition, ATP depletion, and excessive reactive oxygen species (ROS) generation. In addition, UA induced a DNA damage response by increasing intracellular ROS production, thus causing cell cycle arrest at the G0/G1 phase. UA also suppressed aerobic glycolysis by prohibiting the expression and function of Glut1. Considered together, our data demonstrated that UA potentiated the susceptibility of DOX-resistant breast carcinoma cells to DOX by targeting energy metabolism through the AMPK/mTOR/PGC-1α signaling pathway, and it is a potential adjuvant chemotherapeutic candidate in MDR breast cancer.

An oxidative stress-related prognostic signature for indicating the immune status of oral squamous cell carcinoma and guiding clinical treatment

Oral squamous cell carcinoma (OSCC) is the eighth most common cancer worldwide and presents high mortality. Oxidative stress, caused by reactive oxygen species accumulation, plays a crucial role in tumorigenesis, cancer progression, and drug resistance. Nevertheless, the specific prognostic and clinical values of oxidative stress-related genes (OSGs) in OSCC remain unclear. Here, we developed an oxidative stress-related prognostic signature according to mRNA expression data from The Cancer Genome Atlas (TCGA) database and evaluated its connections with the prognosis, clinical features, immune status, immunotherapy, and drug sensitivity of OSCC through a series of bioinformatics analyses. Finally, we filtered out six prognostic OSGs to construct a prognostic signature. On the basis of both TCGA-OSCC and GSE41613 cohorts, the signature was proven to be an independent prognostic factor with high accuracy and was confirmed to be an impactful indicator for predicting the prognosis and immune status of patients with OSCC. Additionally, we found that patients with high-risk scores may obtain greater benefit from immune checkpoint therapy compared to those with low-risk scores, and the risk score presented a close interaction with the tumor microenvironment and chemotherapy sensitivity. The prognostic signature may provide a valid and robust predictive tool that could predict the prognosis and immune status and guide clinicians to develop personalized therapeutic strategies for patients with OSCC.

Long non‑coding RNA CASC11 interacts with YBX1 to promote prostate cancer progression by suppressing the p53 pathway

Prostate cancer (PCa) is one of the principal causes of cancer‑related death worldwide. The roles and mechanisms of long non‑coding RNA (lncRNA) involved in the development of PCa remain incompletely understood. The present study aimed to investigate the role and mechanism of lncRNA in PCa tumorigenesis. In the present study, lncRNA cancer susceptibility candidate 11 (CASC11) was revealed to be a crucial regulator of PCa progression. The expression profiles of CASC11 in PCa were identified through analysis of The Cancer Genome Atlas and Gene Expression Omnibus datasets, and validated in human PCa specimens and cell lines. Gain‑ and loss‑of‑function assays were utilized to explore the biological role of CASC11 in PCa initiation and progression. RNA‑sequencing, RNA pull‑down and RNA immunoprecipitation analyses were used to explore potential mechanisms with which CASC11 may be associated. Rescue experiments were further conducted to confirm this association. The present results revealed that CASC11 was dominantly distributed in the nuclei of PCa cells, and was highly expressed in PCa tissues and cells. Overexpression of CASC11 was markedly associated with increased tumor proliferation and migratory ability. Functionally, decreased proliferation and migration, as well as inhibited xenograft tumor growth, were observed in CASC11‑silenced PCa cells, whereas the opposite effects were detected in CASC11‑overexpressing cells. Mechanistically, CASC11 promoted progression of the cell cycle and competitively interacted with Y‑box binding protein 1 (YBX1) to block the p53 pathway. Given this, poly (β‑amino ester) (PBAE)/small interfering RNA‑CASC11 (si‑CASC11) nanoparticles were applied to inhibit CASC11 expression and enhance the antitumor effect in vivo. The results revealed that PBAE/si‑CASC11 nanoparticles augmented the antitumor efficacy of CASC11 knockdown in vivo. In conclusion, the present study suggested that CASC11 may regulate PCa progression and elucidated a novel CASC11/YBX1/p53 signaling axis, providing a potential lncRNA‑directed therapeutic strategy particularly for the treatment of patients with PCa.

Polo-like Kinase 1 Inhibitors in Human Cancer Therapy: Development and Therapeutic Potential

Polo-like kinase 1 (PLK1) plays an important role in a variety of cellular functions, including the regulation of mitosis, DNA replication, autophagy, and the epithelial-mesenchymal transition (EMT). PLK1 overexpression is often associated with cell proliferation and poor prognosis in cancer patients, making it a promising antitumor target. To date, at least 10 PLK1 inhibitors (PLK1i) have been entered into clinical trials, among which the typical kinase domain (KD) inhibitor BI 6727 (volasertib) was granted "breakthrough therapy designation" by the FDA in 2013. Unfortunately, many other KD inhibitors showed poor specificity, resulting in dose-limiting toxicity, which has greatly impeded their development. Researchers recently discovered many PLK1i with higher selectivity, stronger potency, and better absorption, distribution, metabolism, and elimination (ADME) characteristics. In this review, we emphasize the structure-activity relationships (SARs) of PLK1i, providing insights into new drugs targeting PLK1 for antitumor clinical practice.

Discovery of novel α-carboline derivatives as glycogen synthase kinase-3β inhibitors for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is a chronic and progressive neurodegenerative disease, characterized by irreversible cognitive impairment, memory loss, and behavioral disturbances, ultimately resulting in death. The critical roles of glycogen synthase kinase-3β (GSK-3β) in tau pathology have also received considerable attention. Based on molecular docking studies, a series of novel α-carboline derivatives were designed, synthesized, and evaluated as GSK-3β inhibitors for their various biological activities. Among them, compound ZCH-9 showed the most potent inhibitory activity against GSK-3β, with an IC₅₀ value of 1.71 ± 0.09 µM. The cytotoxicity assay showed that ZCH-9 had low cytotoxicity toward the cell lines SH-SY5Y, HepG2, and HL-7702. Moreover, Western blot analysis indicated that ZCH-9 effectively inhibited hyperphosphorylation of the tau protein in okadaic acid-treated SH-SY5Y cells. The binding mode between ZCH-9 and GSK-3β was analyzed and further clarified throughout the molecular dynamics simulations. In general, these results suggested that the α-carboline-based small-molecule compounds could serve as potential candidates targeting GSK-3β for the treatment of AD.

Targeting lactate metabolism and glycolytic pathways in the tumor microenvironment by natural products: A promising strategy in combating cancer

Anticancer drugs are not purely effective because of their toxicity, side effects, high cost, inaccessibility, and associated resistance. On the other hand, cancer is a complex public health problem that could intelligently adopt different signaling pathways and alter the body's metabolism to escape from the immune system. One of the cancer strategies to metastasize is modifying pH in the tumor microenvironment, ranging between 6.5 and 6.9. As a powerful determiner, lactate is responsible for this acidosis. It is involved in immune stimulation, including innate and adaptive immunity, apoptotic-related factors (Bax/Bcl-2, caspase), and glycolysis pathways (e.g., GLUT-1, PKM2, PFK, HK2, MCT-1, and LDH). Lactate metabolism, in turn, is interconnected with several dysregulated signaling mediators, including PI3K/Akt/mTOR, AMPK, NF-κB, Nrf2, JAK/STAT, and HIF-1α. Because of lactate's emerging and critical role, targeting lactate production and its transporters is important for preventing and managing tumorigenesis. Hence, exploring and developing novel promising anticancer agents to minimize human cancers is urgent. Based on numerous studies, natural secondary metabolites as multi-target alternative compounds with health-promoting properties possess more high effectiveness and low side effects than conventional agents. Besides, the mechanism of multi-targeted natural sources is related to lactate production and cancer-associated cross-talked factors. This review focuses on targeting the lactate metabolism/transporters, and lactate-associated mediators, including glycolytic pathways. Besides, interconnected mediators to lactate metabolism are also targeted by natural products. Accordingly, plant-derived secondary metabolites are introduced as alternative therapies in combating cancer through modulating lactate metabolism and glycolytic pathways.

Modulation of TLR/NF-κB/NLRP Signaling by Bioactive Phytocompounds: A Promising Strategy to Augment Cancer Chemotherapy and Immunotherapy

Background

Tumors often progress to a more aggressive phenotype to resist drugs. Multiple dysregulated pathways are behind this tumor behavior which is known as cancer chemoresistance. Thus, there is an emerging need to discover pivotal signaling pathways involved in the resistance to chemotherapeutic agents and cancer immunotherapy. Reports indicate the critical role of the toll-like receptor (TLR)/nuclear factor-κB (NF-κB)/Nod-like receptor pyrin domain-containing (NLRP) pathway in cancer initiation, progression, and development. Therefore, targeting TLR/NF-κB/NLRP signaling is a promising strategy to augment cancer chemotherapy and immunotherapy and to combat chemoresistance. Considering the potential of phytochemicals in the regulation of multiple dysregulated pathways during cancer initiation, promotion, and progression, such compounds could be suitable candidates against cancer chemoresistance.

Objectives

This is the first comprehensive and systematic review regarding the role of phytochemicals in the mitigation of chemoresistance by regulating the TLR/NF-κB/NLRP signaling pathway in chemotherapy and immunotherapy.

Methods

A comprehensive and systematic review was designed based on Web of Science, PubMed, Scopus, and Cochrane electronic databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to include papers on TLR/NF-κB/NLRP and chemotherapy/immunotherapy/chemoresistance by phytochemicals.

Results

Phytochemicals are promising multi-targeting candidates against the TLR/NF-κB/NLRP signaling pathway and interconnected mediators. Employing phenolic compounds, alkaloids, terpenoids, and sulfur compounds could be a promising strategy for managing cancer chemoresistance through the modulation of the TLR/NF-κB/NLRP signaling pathway. Novel delivery systems of phytochemicals in cancer chemotherapy/immunotherapy are also highlighted.

Conclusion

Targeting TLR/NF-κB/NLRP signaling with bioactive phytocompounds reverses chemoresistance and improves the outcome for chemotherapy and immunotherapy in both preclinical and clinical stages.

N6-Methyladenosine Methylation Regulator RBM15 is a Potential Prognostic Biomarker and Promotes Cell Proliferation in Pancreatic Adenocarcinoma

RNA binding motif protein 15 (RBM15) is a key regulatory factor involved in N6-methyladenosine (m6A) methylation. It has been reported that RBM15 plays an important role in the progress of laryngeal squamous cell carcinoma (LSCC), promoting LSCC migration and invasion. However, the role of RBM15 in human different cancers remains unknown. This study aims to analyze the prognostic value of RBM15, and to demonstrate the correlation between RBM15 expression and tumor immunity, as well as to provide clues for further mechanism research. The results showed that RBM15 was mutated or copy number varied in 25 types of cancer. RBM15 mRNA was abnormally up-regulated across various cancers. Survival analysis suggested high expression of RBM15 was associated with poor prognosis in many cancer types. Among these, it affected patients’ overall survival (OS) in 10 cancer types, disease-free interval (DFI) in 8 cancer types, progression-free interval (PFI) in 12 cancer types and disease-specific survival (DSS) in 7 cancer types. Importantly, in pancreatic adenocarcinoma (PAAD), overexpression of RBM15 is associated with patients’ OS, DFI, PFI, or DSS. In addition, RBM15 expression was positively correlated with immune infiltrating cells in kidney renal clear cell carcinoma (KIRC), brain lower grade glioma (LGG), and PAAD. Moreover, RBM15 expression showed a strong correlation with immune checkpoint markers in PAAD. Cell counting kit-8 (CCK-8) assay showed that knockdown of RBM15 significantly inhibited the proliferation of pancreatic cancer cells. PPI analysis showed USP10, USP24, SMG1, NRAS were closely connected with RBM15 alterations. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that many biological processes (BP), cellular components (CC), molecular functions (MF), cancer related pathways including “sister chromatid cohesion”, “peptidyl-serine phosphorylation”, “cell division”, “nucleoplasm”, “nucleus”, “protein binding”, “protein serine/threonine kinase activity”, “T cell receptor signaling pathway”, “Cell cycle” were regulated by RBM15 alterations. Taken together, pan-cancer analysis of RBM15 suggested it may be served as a prognostic biomarker and immunotherapeutic target for PAAD.

Structure–Activity Relationship of Cytotoxic Natural Products from Indonesian Marine Sponges

Indonesian marine natural products have been one of the most promising sources in the race to obtain potential drugs for cancer treatment. One of the primary producers of cytotoxic compounds is sponges. However, there are still limited sources of comprehensive reviews related to the relationship between the structure of isolated compounds and their cytotoxic activity. This review remarks the attempt to provide a preliminary guidance from the perspective of structure–activity relationship and its participation on marine natural products research. This guidance is segregated by the compound’s classes and their cytotoxic targets to obtain and organized a reliable summary of inter-study of the isolated compounds and their cytotoxicity. Structure–activity relationship is well-known for its ability to tune the bioactivity of a specific compound, especially on synthetic organic chemistry and in silico study but rarely used on natural product chemistry. The present review is intended to narrow down the endless possibilities of cytotoxicity by giving a predictable structure–activity relationship for active compounds. In addition, bioactive framework leads were selected by uncovering a noticeable structure–activity relationship with the intervention of cytotoxic agents from natural sources, especially Indonesian marine sponge.

Hohenbuehelia serotina polysaccharides self-assembled nanoparticles for delivery of quercetin and their anti-proliferative activities during gastrointestinal digestion in vitro

In this study, the self-assembled nanoparticles based on Hohenbuehelia serotina polysaccharides (QC-HSP NPs) were fabricated to encapsulate quercetin for improving its bioavailability. The structural characteristics, physicochemical properties as well as the cytotoxicity activities of QC-HSP NPs during gastrointestinal digestion in vitro were respectively investigated. The results showed that QC-HSP NPs possessed the spherical and smooth surface morphology, with the average particle size of 360 nm and zeta potential of -38.8 mV. Moreover, QC-HSP NPs had excellent physiochemical stabilities, and presented sustained-release characteristics during gastrointestinal digestion in vitro. Compared with undigested ones, QC-HSP NPs after gastrointestinal digestion exhibited the more significant anti-proliferative activity on HeLa cells through accumulation of intracellular ROS, arrest of cell cycle at G2/M phase by regulation of cyclin B1, CDK1, p53 and p21 and induction of apoptosis by ER apoptosis pathway. This study provides a new strategy for designing quercetin-loaded nanoparticles based on natural polysaccharides to improve the bioavailability of quercetin.

The anti-neoplastic activities of aloperine in HeLa cervical cancer cells are associated with inhibition of the IL-6-JAK1-STAT3 feedback loop

Cervical cancer (CC) is recognized as the most common neoplasm in the female reproductive system worldwide. The lack of chemotherapeutic agents with outstanding effectiveness and safety severely compromises the anti-cipated prognosis of patients. Aloperine (ALO) is a natural quinolizidine alkaloid with marked anti-cancer effects on multiple malignancies as well as favorable activity in relieving inflammation, allergies and infection. However, its therapeutic efficacy and underlying mechanism in CC are still unclear. In the current study, MTT assay was employed to evaluate the viability of HeLa cells exposed to ALO to preliminarily estimate the effectiveness of ALO in CC. Then, the effects of ALO on the proliferation and apoptosis of HeLa cells were further investigated by plate colony formation and flow cytometry, respectively, while the migration and invasion of ALO-treated HeLa cells were evaluated using Transwell assay. Moreover, nude mice were subcutaneously inoculated with HeLa cells to demonstrate the anti-CC properties of ALO in vivo. The molecular mechanisms underlying these effects of ALO were evaluated by Western blot and immunohistochemical analysis. This study experimentally demonstrated that ALO inhibited the proliferation of HeLa cells via G2 phase cell cycle arrest. Simultaneously, ALO promoted an increase in the percentage of apoptotic HeLa cells by increasing the Bax/Bcl-2 ratio. Additionally, the migration and invasion of HeLa cells were attenuated by ALO treatment, which was considered to result from inhibition of epithelial-to-mesenchymal transition. For molecular mechanisms, the expression and activation of the IL-6-JAK1-STAT3 feedback loop were markedly suppressed by ALO treatment. This study indicated that ALO markedly suppresses the proliferation, migration and invasion and enhances the apoptosis of HeLa cells. In addition, these prominent anti-CC properties of ALO are associated with repression of the IL-6-JAK1-STAT3 feedback loop.

Targeting Mitochondria by Plant Secondary Metabolites: A Promising Strategy in Combating Parkinson's Disease

Parkinson’s disease (PD) is one of the most prevalent and debilitating neurodegenerative conditions, and is currently on the rise. Several dysregulated pathways are behind the pathogenesis of PD; however, the critical targets remain unclear. Accordingly, there is an urgent need to reveal the key dysregulated pathways in PD. Prevailing reports have highlighted the importance of mitochondrial and cross-talked mediators in neurological disorders, genetic changes, and related complications of PD. Multiple pathophysiological mechanisms of PD, as well as the low efficacy and side effects of conventional neuroprotective therapies, drive the need for finding novel alternative agents. Recently, much attention has been paid to using plant secondary metabolites (e.g., flavonoids/phenolic compounds, alkaloids, and terpenoids) in the modulation of PD-associated manifestations by targeting mitochondria. In this line, plant secondary metabolites have shown promising potential for the simultaneous modulation of mitochondrial apoptosis and reactive oxygen species. This review aimed to address mitochondria and multiple dysregulated pathways in PD by plant-derived secondary metabolites.

Carcinogenic effect of adenylosuccinate lyase (ADSL) in prostate cancer development and progression through the cell cycle pathway

Background

Prostate cancer (PCa) is still a serious male malignant disease across the world. However, no exact pathogenesis had been explained. Although adenylosuccinate lyase (ADSL) gene was identified to be important in PCa early in 1987, its comprehensive functions for PCa have not been presented.

Methods

The cBioPortal for Cancer Genomics, Oncomine and GEO database were retrieved to investigate the associations between of the ADSL gene and PCa. Then, the PC-3, DU145 and C4-2B cell lines were applied in vitro experiments. RNA sequencing and further western blot (WB) were applied to explore the potential mechanisms of ADSL gene in PCa.

Results

Based on PCa clinical datasets, we firstly found ADSL gene highly expressed in PCa tissues. Moreover, its transcript level increased in the metastatic PCa further. Elevated ADSL gene expression indicated a poor prognosis of PCa. While inhibiting the expression of ADSL with siRNA, the ability of cell proliferation and migration all declined markedly, with increased cell apoptosis inversely. Most of cells were blocked in the G0/G1 phase. Additionally, RNA sequencing also discovered the inactivity of cell cycle pathway after ADSL knockdown, which had also confirmed on the proteins levels.

Conclusions

Our study identified the ADSL as an oncogene of PCa through regulating the cell cycle pathway firstly, with explicit cell and clinical phenotypes. Further mechanisms were needed to confirm its carcinogenic effect.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02174-6.

In vitro Effect of Harmine Alkaloid and Its N-Methyl Derivatives Against Toxoplasma gondii

Toxoplasmosis is one of the most prevalent and neglected zoonotic global diseases caused by Toxoplasma gondii. The current pharmacological treatments show clinical limitations, and therefore, the search for new drugs is an urgent need in order to eradicate this infection. Due to their intrinsic biological activities, β-carboline (βC) alkaloids might represent a good alternative that deserves further investigations. In this context, the in vitro anti-T. gondii activity of three βCs, harmine (1), 2-methyl-harminium (2), and 9-methyl-harmine (3), was evaluated herein. Briefly, the three alkaloids exerted direct effects on the parasite invasion and/or replication capability. Replication rates of intracellular treated tachyzoites were also affected in a dose-dependent manner, at noncytotoxic concentrations for host cells. Additionally, cell cycle analysis revealed that both methyl-derivatives 2 and 3 induce parasite arrest in S/M phases. Compound 3 showed the highest irreversible parasite growth inhibition, with a half maximal inhibitory concentration (IC50) value of 1.8 ± 0.2 μM and a selectivity index (SI) of 17.2 at 4 days post infection. Due to high replication rates, tachyzoites are frequently subjected to DNA double-strand breaks (DSBs). This highly toxic lesion triggers a series of DNA damage response reactions, starting with a kinase cascade that phosphorylates a large number of substrates, including the histone H2A.X to lead the early DSB marker γH2A.X. Western blot studies showed that basal expression of γH2A.X was reduced in the presence of 3. Interestingly, the typical increase in γH2A.X levels produced by camptothecin (CPT), a drug that generates DSB, was not observed when CPT was co-administered with 3. These findings suggest that 3 might disrupt Toxoplasma DNA damage response.

Dehydrocrenatidine extracted from Picrasma quassioides induces the apoptosis of nasopharyngeal carcinoma cells through the JNK and ERK signaling pathways

Nasopharyngeal carcinoma (NPC) is an indicator disease in Asia due to its unique geographical and ethnic distribution. Dehydrocrenatidine (DC) is a β-carboline alkaloid abundantly present in Picrasma quassioides (D. Don) Benn, a deciduous shrub or small tree native to temperate regions of southern Asia, and β-carboline alkaloids play anti-inflammatory and antiproliferative roles in various cancers. However, the mechanism and function of DC in human NPC cells remain only partially explored. The present study aimed to examine the cytotoxicity and biochemical role of DC in human NPC cells. The MTT method, cell cycle analysis, DAPI determination, Annexin V/PI double staining, and mitochondrial membrane potential examination were performed to evaluate the effects of DC treatment on human NPC cell lines. In addition, western blotting analysis was used to explore the effect of DC on apoptosis and signaling pathways in related proteins. The analysis results confirmed that DC significantly reduced the viability of NPC cell lines in a dose- and time-dependent manner and induced apoptosis through internal and external apoptotic pathways (including cell cycle arrest, altered mitochondrial membrane potential, and activated death receptors). Western blot analysis illustrated that DC's effect on related proteins in the mitogen-activated protein kinase pathway can induce apoptosis by enhancing ERK phosphorylation and inhibiting Janus kinase (JNK) phosphorylation. Notably, DC induced apoptosis by affecting the phosphorylation of JNK and ERK, and DC and inhibitors (SP600125 and U0126) in combination restored the overexpression of p-JNK and p-ERK. To date, this is the first study to confirm the apoptosis pathway induced by DC phosphorylation of p-JNK and p-REK in human NPC. On the basis of evidence obtained from this study, DC targeting the inhibition of NPC cell lines may be a promising future strategy for NPC treatment.

Small Molecule Inhibitors of DYRK1A Identified by Computational and Experimental Approaches

Dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) is a protein kinase with diverse functions in cell regulation. Abnormal expression and activity of DYRK1A contribute to numerous human malignancies, Down syndrome, and Alzheimer's disease. Notably, DYRK1A has been proposed as a potential therapeutic target for the treatment of diabetes because of its key role in pancreatic β-cell proliferation. Consequently, DYRK1A is an attractive drug target for a variety of diseases. Here, we report the identification of several DYRK1A inhibitors using our in-house topological water network-based approach. All inhibitors were further verified by in vitro assay.