Anticancer effect of terpenes: focus on malignant melanoma

Terpenoids: Unlocking Their Potential on Cancer Glucose Metabolism

Cancer incidence has increased globally and has become the leading cause of death in the majority of countries. Many cancers have altered energy metabolism pathways, such as increased glucose uptake and glycolysis, as well as decreased oxidative phosphorylation. This is known as the Warburg effect, where cancer cells become more reliant on glucose to generate energy and produce lactate as an end product, even when oxygen is present. These are attributed to the overexpression of key glycolytic enzymes, glucose transporters, and related signaling pathways that occur in cancer cells. Therefore, overcoming metabolic alterations in cancer cells has recently become a target for therapeutic approaches. Natural products have played a key role in drug discovery, especially for cancer and infectious diseases. In this review, we are going to focus on terpenoids, which are gradually gaining popularity among drug researchers due to their reported anti-cancer effects via cell cycle arrest, induction of apoptosis, reduction of proliferation, and metastasis. This review summarizes the potential of 13 terpenoid compounds as anti-glycolytic inhibitors in different cancer models, primarily by inhibiting the glucose uptake and the generation of lactate, as well as by downregulating enzymes associated to glycolysis. As a conclusion, disruption of cancer cell glycolysis may be responsible for the anti-cancer activity of terpenoids.

Analysis on the involvement of phosphoglycerate mutase 1 in the aerobic glycolysis of melanoma cells

BACKGROUND

The aim of this study was to investigate the mechanism through which phosphoglycerate mutase 1 (PGAM1) drives aerobic glycolysis and promotes tumor aggressiveness in melanoma and to evaluate its potential as a therapeutic target.

METHODS

The survival of patients with skin cutaneous melanoma was predicted. The expression of PGAM1 in melanoma cells was measured, and then the levels of markers related to apoptosis, glycolysis and immune responses in melanoma cells cultured with or without CD8+ T cells were detected. The effects of PGAM1 knockdown on the malignant phenotypes and extracellular acidification rate (ECAR) of melanoma cells were analyzed.

RESULTS

High-expressed PGAM1 was predictive of a poor prognosis of melanoma. The viability, proliferation and invasion as well as glycolysis of PGAM1-silenced melanoma cells were suppressed. PGAM1 silencing lowered the expressions of glycolysis-related markers and anti-apoptosis marker BCL2 but promoted that of BAX, a pro-apoptosis marker. Downregulated levels of immune responses-related markers were observed after PGAM1 knockdown. POMHEX, a glycolysis inhibitor, reduced glycolysis and suppressed the levels of immune responses-related markers and anti-apoptosis marker BCL2.

CONCLUSION

This study revealed the involvement of PGAM1 in the aerobic glycolysis of melanoma, providing novel insights into the molecular mechanisms of melanoma progression.

Anti-tumor mechanism of artesunate

Artesunate (ART) is a classic antimalarial drug with high efficiency, low toxicity and tolerance. It has been shown to be safe and has good anti-tumor effect. Existing clinical studies have shown that the anti-tumor mechanisms of ART mainly include inducing apoptosis and autophagy of tumor cells, affecting tumor microenvironment, regulating immune response, overcoming drug resistance, as well as inhibiting tumor cell proliferation, migration, invasion, and angiogenesis. ART has been proven to fight against lung cancer, hepatocarcinoma, lymphoma, multiple myeloma, leukemia, colorectal cancer, ovarian cancer, cervical cancer, malignant melanoma, oral squamous cell carcinoma, bladder cancer, prostate cancer and other neoplasms. In this review, we highlight the effects of ART on various tumors with an emphasis on its anti-tumor mechanism, which is helpful to propose the potential research directions of ART and expand its clinical application.

Anticancer Effect of Cycas media: Molecular Basis Through Modulation of PI3K/AKT/mTOR Signaling Pathway

Many researchers are focusing on screening the biological activities of plants owing to their safety and possible pharmacological actions. Consequently, we aimed to explore the antiproliferative and cytotoxic properties of Cycas media methanolic extract on HepG2 cell lines. Moreover, we also explore the antitumor action against the experimentally induced solid Ehrlich carcinoma (SEC) model and investigate the possible involved molecular mechanisms. Also, the antibacterial action of the extract was elucidated. Different concentrations of the extract were incubated with HepG2 to determine cytotoxicity, followed by cell cycle analysis. The in vivo experiment was accomplished by grouping the animals into four different groups (n = 10); normal control, SEC, C. media 100, and C. media 200. The extract was administered at 100 and 200 mg/kg. Tumor volume, tumor inhibition rate, toxicity profile, and antioxidant biomarkers were determined. Moreover, the PI3K/AKT/mTOR signaling pathway was investigated as a possible underlying antitumor mechanism. The tumor control group showed a remarkable upregulation for PI3K, p-AKT, and p-mTOR, along with downregulation for the antioxidant SOD and GPX4, as well as decreased levels of GSH and MDA. C. media extract reversed these parameters to a significant level and the higher dose showed a superior antitumor effect. C. media extract showed antiproliferative effects against HepG2 cells, along with a suppressive action on the PI3K/AKT/mTOR pathway and an antioxidant effect. Additionally, C. media had antibacterial consequences against S. aureus isolates with minimum inhibitory concentrations from 32 to 128 µg/mL. It also caused a noteworthy growth delay as well as a notable reduction in the membrane integrity of S. aureus isolates. These beneficial outcomes suggest C. media to have potential antitumor and antibacterial activities.

Ursolic acid interaction with transcription factors BRAF, V600E, and V600K: a computational approach towards new potential melanoma treatments

CONTEXT

Melanoma is one of the cancers with the highest mortality rate for its ability to metastasize. Several targets have undergone investigation for the development of drugs against this pathology. One of the main targets is the kinase BRAF (RAF, rapidly accelerated fibrosarcoma). The most common mutation in melanoma is BRAFV600E and has been reported in 50-90% of patients with melanoma. Due to the relevance of the BRAFV600E mutation, inhibitors to this kinase have been developed, vemurafenib-OMe and dabrafenib. Ursolic acid (UA) is a pentacyclic triterpene with a privileged structure, the pentacycle scaffold, which allows to have a broad variety of biological activity; the most studied is its anticancer capacity. In this work, we reported the interaction profile of vemurafenib-OMe, dabrafenib, and UA, to define whether UA has binding capacity to BRAFWT, BRAFV600E, and BRAFV600K. Homology modeling of BRAFWT, V600E, and V600K; molecular docking; and molecular dynamics simulations were carried out and interactions and residues relevant to the binding of the inhibitors were obtained. We found that UA, like the inhibitors, presents hydrogen bond interactions, and hydrophobic interactions of van der Waals, and π-stacking with I463, Q530, C532, and F583. The ΔG of ursolic acid in complex with BRAFV600K (- 63.31 kcal/mol) is comparable to the ΔG of the selective inhibitor dabrafenib (- 63.32 kcal/mol) in complex to BRAFV600K and presents a ΔG like vemurafenib-OMe with BRAFWT and V600E. With this information, ursolic acid could be considered as a lead compound for design cycles and to optimize the binding profile and the selectivity towards mutations for the development of new selective inhibitors for BRAFV600E and V600K to new potential melanoma treatments.

METHODS

The homology modeling calculations were executed on the public servers I-TASSER and ROBETTA, followed by molecular docking calculations using AutoGrid 4.2.6, AutoDockGPU 1.5.3, and AutoDockTools 1.5.6. Molecular dynamics and metadynamics simulations were performed in the Desmond module of the academic version of the Schrödinger-Maestro 2020-4 program, utilizing the OPLS-2005 force field. Ligand-protein interactions were evaluated using Schrödinger-Maestro program, LigPlot + , and PLIP (protein-ligand interaction profiler). Finally, all of the protein figures presented in this article were made in the PyMOL program.

From Knallgas Bacterium to Promising Biomanufacturing Host: The Evolution of Cupriavidus necator

The expanding field of synthetic biology requires diversification of microbial chassis to expedite the transition from a fossil fuel-dependent economy to a sustainable bioeconomy. Relying exclusively on established model organisms such as Escherichia coli and Saccharomyces cerevisiae may not suffice to drive the profound advancements needed in biotechnology. In this context, Cupriavidus necator, an extraordinarily versatile microorganism, has emerged as a potential catalyst for transformative breakthroughs in industrial biomanufacturing. This comprehensive book chapter offers an in-depth review of the remarkable technological progress achieved by C. necator in the past decade, with a specific focus on the fields of molecular biology tools, metabolic engineering, and innovative fermentation strategies. Through this exploration, we aim to shed light on the pivotal role of C. necator in shaping the future of sustainable bioprocessing and bioproduct development.

Epoxidation of perillyl alcohol by engineered bacterial cytochrome P450 BM3

Perillyl alcohol (POH) is a secondary metabolite of plants. POH and its derivatives are known to be effective as an anticancer treatment. In this study, oxidative derivatives of POH, which are difficult to synthesize chemically, were synthesized using the engineered bacterial cytochrome P450 BM3 (CYP102A1) as a biocatalyst. The activity of wild-type (WT) CYP102A1 and 29 engineered enzymes toward POH was screened using a high-performance liquid chromatography. They produced one major product. Among them, the engineered CYP102A1 M601 mutant with seven mutations (R47L/F81I/F87V/E143G/L150F/L188Q/E267V) showed the highest conversion, 6.4-fold higher than the WT. Structure modeling using AlphFold2 and PyMoL suggests that mutations near the water channel may be responsible for the increased catalytic activity of the M601 mutant. The major product was identified as a POH-8,9-epoxide by gas chromatography-mass spectrometry and nuclear magnetic resonance analysis. The optimal temperature and pH for the product formation were 35 °C and pH 7.4, respectively. The kcat and Km of M601 were 540 min-1 and 2.77 mM, respectively. To improve POH-8,9-epoxide production, substrate concentration and reaction time were optimized. The optimal condition for POH-8,9-epoxide production by M601 was 5.0 mM POH, pH 7.4, 35 ℃, and 6 h reaction, which produced the highest concentration of 1.72 mM. Therefore, the biosynthesis of POH-8,9-epoxide using M601 as a biocatalyst is suggested to be an efficient and sustainable synthetic process that can be applied to chemical and pharmaceutical industries.

Phytochemicals regulate cancer metabolism through modulation of the AMPK/PGC-1α signaling pathway

BACKGROUND

Due to the complex pathophysiological mechanisms involved in cancer progression and metastasis, current therapeutic approaches lack efficacy and have significant adverse effects. Therefore, it is essential to establish novel strategies for combating cancer. Phytochemicals, which possess multiple biological activities, such as antioxidant, anti-inflammatory, antimutagenic, immunomodulatory, antiproliferative, anti-angiogenesis, and antimetastatic properties, can regulate cancer progression and interfere in various stages of cancer development by suppressing various signaling pathways.

METHODS

The current systematic and comprehensive review was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) criteria, using electronic databases, including PubMed, Scopus, and Science Direct, until the end of December 2023. After excluding unrelated articles, 111 related articles were included in this systematic review.

RESULTS

In this current review, the major signaling pathways of cancer metabolism are highlighted with the promising anticancer role of phytochemicals. This was through their ability to regulate the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) signaling pathway. The AMPK/PGC-1α signaling pathway plays a crucial role in cancer cell metabolism via targeting energy homeostasis and mitochondria biogenesis, glucose oxidation, and fatty acid oxidation, thereby generating ATP for cell growth. As a result, targeting this signaling pathway may represent a novel approach to cancer treatment. Accordingly, alkaloids, phenolic compounds, terpene/terpenoids, and miscellaneous phytochemicals have been introduced as promising anticancer agents by regulating the AMPK/PGC-1α signaling pathway. Novel delivery systems of phytochemicals targeting the AMPK/PGC-1α pathway in combating cancer are also highlighted in this review.

Phytocompounds and Nanoformulations for Anticancer Therapy: A Review

Cancer is a complex disease that affects millions of people and remains a major public health problem worldwide. Conventional cancer treatments, including surgery, chemotherapy, immunotherapy, and radiotherapy, have limited achievements and multiple drawbacks, among which are healthy tissue damage and multidrug-resistant phenotype onset. Increasing evidence shows that many plants' natural products, as well as their bioactive compounds, have promising anticancer activity and exhibit minimal toxicity compared to conventional anticancer drugs. However, their widespread use in cancer therapy is severely restricted by limitations in terms of their water solubility, absorption, lack of stability, bioavailability, and selective targeting. The use of nanoformulations for plants' natural product transportation and delivery could be helpful in overcoming these limitations, thus enhancing their therapeutic efficacy and providing the basis for improved anticancer treatment strategies. The present review is aimed at providing an update on some phytocompounds (curcumin, resveratrol, quercetin, and cannabinoids, among others) and their main nanoformulations showing antitumor activities, both in vitro and in vivo, against such different human cancer types as breast and colorectal cancer, lymphomas, malignant melanoma, glioblastoma multiforme, and osteosarcoma. The intracellular pathways underlying phytocompound anticancer activity and the main advantages of nanoformulation employment are also examined. Finally, this review critically analyzes the research gaps and limitations causing the limited success of phytocompounds' and nanoformulations' clinical translation.

Bluish veil detection and lesion classification using custom deep learnable layers with explainable artificial intelligence (XAI)

Melanoma, one of the deadliest types of skin cancer, accounts for thousands of fatalities globally. The bluish, blue-whitish, or blue-white veil (BWV) is a critical feature for diagnosing melanoma, yet research into detecting BWV in dermatological images is limited. This study utilizes a non-annotated skin lesion dataset, which is converted into an annotated dataset using a proposed imaging algorithm (color threshold techniques) on lesion patches based on color palettes. A Deep Convolutional Neural Network (DCNN) is designed and trained separately on three individual and combined dermoscopic datasets, using custom layers instead of standard activation function layers. The model is developed to categorize skin lesions based on the presence of BWV. The proposed DCNN demonstrates superior performance compared to the conventional BWV detection models across different datasets. The model achieves a testing accuracy of 85.71 % on the augmented PH2 dataset, 95.00 % on the augmented ISIC archive dataset, 95.05 % on the combined augmented (PH2+ISIC archive) dataset, and 90.00 % on the Derm7pt dataset. An explainable artificial intelligence (XAI) algorithm is subsequently applied to interpret the DCNN's decision-making process about the BWV detection. The proposed approach, coupled with XAI, significantly improves the detection of BWV in skin lesions, outperforming existing models and providing a robust tool for early melanoma diagnosis.

Prospects of compounds of herbal plants as anticancer agents: a comprehensive review from molecular pathways

Cancer refers to the proliferation and multiplication of aberrant cells inside the human body, characterized by their capacity to proliferate and infiltrate various anatomical regions. Numerous biochemical pathways and signaling molecules have an impact on the cancer auto biogenesis process. The regulation of crucial cellular processes necessary for cell survival and proliferation, which are triggered by phytochemicals, is significantly influenced by signaling pathways. These pathways or components are regulated by phytochemicals. Medicinal plants are a significant reservoir of diverse anticancer medications employed in chemotherapy. The anticancer effects of phytochemicals are mediated by several methods, including induction of apoptosis, cessation of the cell cycle, inhibition of kinases, and prevention of carcinogenic substances. This paper analyzes the phytochemistry of seven prominent plant constituents, namely, alkaloids, tannins, flavonoids, phenols, steroids, terpenoids, and saponins, focusing on the involvement of the MAPK/ERK pathway, TNF signaling, death receptors, p53, p38, and actin dynamics. Hence, this review has examined a range of phytochemicals, encompassing their structural characteristics and potential anticancer mechanisms. It has underscored the significance of plant-derived bioactive compounds in the prevention of cancer, utilizing diverse molecular pathways. In addition, this endeavor also seeks to incentivize scientists to carry out clinical trials on anticancer medications derived from plants.

Targeting Chemoresistance in Advanced Bladder Cancers with a Novel Adjuvant Strategy

Advanced urinary bladder cancer (BC) is characterized by rapid progression and development of therapy resistance. About 30% of the patients are diagnosed with high-grade tumors (Grade >T2a). A typical non-surgical treatment is systemic chemotherapy using Cisplatin (C) and Gemcitabine (G). However, treatment failure and subsequent disease progression are common in treated patients, and adjuvant therapies are not significantly effective. The therapeutic potential of a molecular hybrid of Ursolic Acid (UA), a pentacyclic-triterpene conjugated to N-methyl piperazine (UA4), was tested on both naïve (WT) and Gemcitabine-resistant (GemR) variants of two human invasive BC cell lines, 5637 and T24. UA4 killed 5637 (4µM), T24 (4µM) WT, and GemR cells invitro at equal potency. Pretreatment with UA4 followed by G synergistically killed WT and GemR cells by >50% compared to G followed by UA4. Oral gavage of UA4 (100 mg/kg) inhibited WT and GemR tumor growth in athymic mice. UA4 + G was more effective against GemR tumors than either drug alone. Studies revealed cytotoxic autophagy as a mechanism of UA4 cytotoxicity. UA4 induced moderate apoptosis in T24 but not in 5637 cells. Mitochondrial integrity and function were most affected by UA4 due to high levels of reactive oxygen species (ROS), disruption of mitochondrial membrane, and cell cycle arrest. These effects were enhanced in the UA4+G combination. UA4 was well-tolerated in mice, and oral gavage led to a serum level >1µM with no systemic toxicity. These results show the potential of UA4 as a non-toxic alternative treatment for high-grade BC.

Therapeutic Effects of Natural Products on Liver Cancer and Their Potential Mechanisms

Liver cancer ranks third globally among causes of cancer-related deaths, posing a significant public health challenge. However, current treatments are inadequate, prompting a growing demand for novel, safe, and effective therapies. Natural products (NPs) have emerged as promising candidates in drug development due to their diverse biological activities, low toxicity, and minimal side effects. This paper begins by reviewing existing treatment methods and drugs for liver cancer. It then summarizes the therapeutic effects of NPs sourced from various origins on liver cancer. Finally, we analyze the potential mechanisms of NPs in treating liver cancer, including inhibition of angiogenesis, migration, and invasion; regulation of the cell cycle; induction of apoptosis, autophagy, pyroptosis, and ferroptosis; influence on tumor metabolism; immune regulation; regulation of intestinal function; and regulation of key signaling pathways. This systematic review aims to provide a comprehensive overview of NPs research in liver cancer treatment, offering a foundation for further development and application in pharmaceuticals and functional foods.

The Anticancer Activities of Natural Terpenoids That Inhibit Both Melanoma and Non-Melanoma Skin Cancers

The prevalence of two major types of skin cancer, melanoma and non-melanoma skin cancer, has been increasing worldwide. Skin cancer incidence is estimated to rise continuously over the next 20 years due to ozone depletion and an increased life expectancy. Chemotherapeutic agents could affect healthy cells, and thus may be toxic to them and cause numerous side effects or drug resistance. Phytochemicals that are naturally occurring in fruits, plants, and herbs are known to possess various bioactive properties, including anticancer properties. Although the effects of phytochemicals are relatively milder than chemotherapeutic agents, the long-term intake of phytochemicals may be effective and safe in preventing tumor development in humans. Diverse phytochemicals have shown anti-tumorigenic activities for either melanoma or non-melanoma skin cancer. In this review, we focused on summarizing recent research findings of the natural and dietary terpenoids (eucalyptol, eugenol, geraniol, linalool, and ursolic acid) that have anticancer activities for both melanoma and non-melanoma skin cancers. These terpenoids may be helpful to protect skin collectively to prevent tumorigenesis of both melanoma and nonmelanoma skin cancers.

Cryptotanshinone inhibits PFK-mediated aerobic glycolysis by activating AMPK pathway leading to blockade of cutaneous melanoma

BACKGROUND

Cutaneous melanoma is a kind of skin malignancy with low morbidity but high mortality. Cryptotanshinone (CPT), an important component of salvia miltiorrhiza has potent anti-tumor activity and also indicates therapeutic effect on dermatosis. So we thought that CPT maybe a potential agent for therapy of cutaneous melanoma.

METHODS

B16F10 and A375 melanoma cells were used for in vitro assay. Tumor graft models were made in C57BL/6N and BALB/c nude mice for in vivo assay. Seahorse XF Glycolysis Stress Test Kit was used to detect extracellular acidification rate and oxygen consumption rate. Si-RNAs were used for knocking down adenosine monophosphate-activated protein kinase (AMPK) expression in melanoma cells.

RESULTS

CPT could inhibit the proliferation of melanoma cells. Meanwhile, CPT changed the glucose metabolism and inhibited phosphofructokinase (PFK)-mediated glycolysis in melanoma cells to a certain extent. Importantly, CPT activated AMPK and inhibited the expression of hypoxia inducible factor 1α (HIF-1α). Both AMPK inhibitor and silencing AMPK could partially reverse CPT's effect on cell proliferation, cell apoptosis and glycolysis. Finally, in vivo experimental data demonstrated that CPT blocked the growth of melanoma, in which was dependent on the glycolysis-mediated cell proliferation.

CONCLUSIONS

CPT activated AMPK and then inhibited PFK-mediated aerobic glycolysis leading to inhibition of growth of cutaneous melanoma. CPT should be a promising anti-melanoma agent for clinical melanoma therapy.

Natural bioactive compounds and STAT3 against hepatocellular carcinoma: An update

Hepatocellular carcinoma (HCC) is a challenging and very fatal liver cancer. The signal transducer and activator of transcription 3 (STAT3) pathway is a crucial regulator of tumor development and are ubiquitously active in HCC. Therefore, targeting STAT3 has emerged as a promising approach for preventing and treating HCC. Various natural bioactive compounds (NBCs) have been proven to target STAT3 and have the potential to prevent and treat HCC as STAT3 inhibitors. Numerous kinds of STAT3 inhibitors have been identified, including small molecule inhibitors, peptide inhibitors, and oligonucleotide inhibitors. Due to the undesirable side effects of the conventional therapeutic drugs against HCC, the focus is shifted to NBCs derived from plants and other natural sources. NBCs can be broadly classified into the categories of terpenes, alkaloids, carotenoids, and phenols. Most of the compounds belong to the family of terpenes, which prevent tumorigenesis by inhibiting STAT3 nuclear translocation. Further, through STAT3 inhibition, terpenes downregulate matrix metalloprotease 2 (MMP2), matrix metalloprotease 9 (MMP9) and vascular endothelial growth factor (VEGF), modulating metastasis. Terpenes also suppress the anti-apoptotic proteins and cell cycle markers. This review provides comprehensive information related to STAT3 abrogation by NBCs in HCC with in vitro and in vivo evidences.

Recent Advances in Chemistry and Antioxidant/Anticancer Biology of Monoterpene and Meroterpenoid Natural Product

Monoterpenes and meroterpenes are two large classes of isoprene-based molecules produced by terrestrial plants and unicellular organisms as diverse secondary metabolites. The global rising incidence of cancer has led to a renewed interest in natural products. These monoterpenes and meroterpenes represent a novel source of molecular scaffolds that can serve as medicinal chemistry platforms for the development of potential preclinical leads. Furthermore, some of these natural products are either abundant, or their synthetic strategies are scalable as it will be indicated here, facilitating their derivatization to expand their scope in drug discovery. This review is a collection of representative updates (from 2016-2023) in biologically active monoterpene and meroterpenoid natural products and focuses on the recent findings of the pharmacological potential of these bioactive compounds as well as the newly developed synthetic strategies employed to access them. Particular emphasis will be placed on the anticancer and antioxidant potential of these compounds in order to raise knowledge for further investigations into the development of potential anti-cancer therapeutics. The mounting experimental evidence from various research groups across the globe regarding the use of these natural products at pre-clinical levels, renders them a fast-track research area worth of attention.