Alkaloids as Natural NRF2 Inhibitors: Chemoprevention and Cytotoxic Action in Cancer

Utilizing Indigenous Flora in East Africa for Breast Cancer Treatment: An Overview

BACKGROUND

Breast cancer is a significant global health challenge, contributing substantially to cancer- related deaths. Conventional treatment methods, including hormone therapy, chemotherapy, surgical interventions, and radiation, have long been utilized. However, these traditional treatments are often associated with serious side effects and drug resistance, limiting their efficacy.

AIM

This review aims to explore the potential of medicinal plants used in breast cancer management in East Africa, focusing on their bioactive compounds and anticancer properties.

METHODS

A comprehensive literature search was conducted to examine the effectiveness of medicinal plants in treating breast cancer across Kenya, Ethiopia, Uganda, Tanzania, and Rwanda. Relevant studies published between 2003 and 2023 were identified using keywords related to breast cancer and medicinal plants. The search was performed across multiple databases, including Google Scholar, PubMed, Scopus, Web of Science Core Collection, and Science Direct.

RESULTS

Numerous natural compounds found in East African medicinal plants including Cymbopogon citratus (Lemongrass,) Tabebuia avellanedae, Prunus africana (African Cherry), Euclea divinorum, Berberis holstii, Withania somnifera (Ashwagandha, Curcuma longa (Turmeric), Garcinia mangostana (Mangosteen, Vitis vinifera (Grapevine), Eugenia jambolana (Java Plum), Moringa oleifera (Drumstick Tree), Camellia sinensis (Tea), Glycine max (Soybean), Catharanthus roseus, Madagascar Periwinkle), Rhus vulgaris (Wild Currant) exhibit significant anticancer properties. These compounds have demonstrated the ability to reduce breast cancer aggressiveness, inhibit cancer cell proliferation, and modulate cancer-related pathways. Current research focuses on these natural and dietary compounds to develop more effective strategies for treating breast cancer.

CONCLUSION

The findings suggested that East African medicinal plants hold promise as complementary treatments for breast cancer, offering potential benefits such as affordability, cultural appropriateness, and sustainability. Further research into these plants and their bioactive compounds could revolutionize breast cancer treatment, improving survival rates and addressing the rising incidence of breast cancer-related fatalities. Other: The review underscores the importance of continued research, conservation, and the integration of ancient healing methods to fully harness the potential of East African flora in breast cancer management.

NRF2 Modulators of Plant Origin and Their Ability to Overcome Multidrug Resistance in Cancers

Cancer is one of the most common causes of death in the world. Despite the fact that there are many types of therapies available, cancer treatment remains a major challenge. The main reason for the ineffectiveness of chemotherapy is the acquisition of multidrug resistance (MDR) by cancer cells. One of the factors responsible for the acquisition of MDR is the NRF2 transcription factor, which regulates the expression of proteins such as HO-1, NQO1, MRP1, MRP2, and GST. In normal cells, NRF2 is the first line of defense against oxidative stress, thereby preventing carcinogenesis. Still, its hyperactivation in cancer cells causes them to acquire MDR, which significantly reduces or eliminates the effectiveness of chemotherapy. Considering the important role NRF2 plays in the acquisition of MDR, its modulators and, above all, inhibitors are being sought after, including among compounds of plant origin. NRF2 inhibition may prove to be a key element of anticancer therapy. This review summarizes the current state of knowledge about plant NRF2 inhibitors and presents the effects of their use in overcoming MDR in cancer.

Identification of Penexanthone A as a Novel Chemosensitizer to Induce Ferroptosis by Targeting Nrf2 in Human Colorectal Cancer Cells

Ferroptosis has emerged as a potential mechanism for enhancing the efficacy of chemotherapy in cancer treatment. By suppressing nuclear factor erythroid 2-related factor 2 (Nrf2), cancer cells may lose their ability to counteract the oxidative stress induced by chemotherapy, thereby becoming more susceptible to ferroptosis. In this study, we investigate the potential of penexanthone A (PXA), a xanthone dimer component derived from the endophytic fungus Diaporthe goulteri, obtained from mangrove plant Acanthus ilicifolius, to enhance the therapeutic effect of cisplatin (CDDP) on colorectal cancer (CRC) by inhibiting Nrf2. The present study reported that PXA significantly improved the ability of CDDP to inhibit the activity of and induce apoptosis in CRC cells. Moreover, PXA was found to increase the level of oxidative stress and DNA damage caused by CDDP. In addition, the overexpression of Nrf2 reversed the DNA damage and ferroptosis induced by the combination of PXA and CDDP. In vivo experiments using zebrafish xenograft models demonstrated that PXA enhanced the therapeutic effect of CDDP on CRC. These studies suggest that PXA enhanced the sensitivity of CRC to CDDP and induce ferroptosis by targeting Nrf2 inhibition, indicating that PXA might serve as a novel anticancer drug in combination chemotherapy.

Crebanine mitigates glucocorticoid-induced osteonecrosis of the femoral head by restoring bone remodelling homeostasis via attenuating oxidative stress

The onset of osteonecrosis of the femoral head (ONFH) is intimately associated with the extensive administration of glucocorticoids (GCs). Long-term stimulation of GCs can induce oxidative stress in both osteoclasts (OCs) and osteoblasts (OBs), resulting in the disturbance of bone remodelling. An alkaloid named crebanine (CN) demonstrates pharmacological properties including anti-inflammation and reactive oxygen species (ROS) modulation. Our objective is to assess the therapeutic potential of CN in treating ONFH and elucidate the associated underlying mechanisms. The network pharmacology analysis uncovered that CN played a role in regulating ROS metabolism. In vitro, CN demonstrated its ability to reduce the dexamethasone (DEX)-stimulated generation of OCs and suppress their resorptive function by downregulating the level of osteoclast marker genes. Concurrently, CN also mitigated DEX-induced damage to OBs, facilitating the restoration of osteoblast marker gene expression, cellular differentiation and function. These effects were achieved by CN augmenting the antioxidant system to reduce intracellular ROS levels. Furthermore, in vitro results were corroborated by micro-CT and histological data, which also showed that CN attenuated MPS-induced ONFH in mice. This study highlights the therapeutic potential of CN in counteracting GCs-induced ONFH.

Programmable activation of berbamine and photosensitizers for enhanced photodynamic therapy using emission-switchable upconversion nanoparticles

Photodynamic therapy (PDT) shows great potential in precision tumor treatment. However, its efficacy is inhibited by the antioxidant defense capacities of tumor cells. To address this challenge, a near-infrared light-controlled nanosystem (UCNPs@mSiO2@Azo@ZnPc&BBM, PB@UA) was developed using emission-switchable upconversion nanoparticles (UCNPs) to independently and precisely control the release of berbamine (BBM) and activation of photosensitizer for enhanced PDT in deep tissues. Firstly, BBM release was triggered by exciting PB@UA at 980 nm. The BBM could inhibit the activities of antioxidant enzymes and disrupt calcium ion regulation, making the tumor cells more susceptible to ROS-induced cell death in the following PDT treatment. The PDT was initiated by irradiating the photosensitizers of ZnPc on PB@UA at 808 nm and achieved a tumor inhibition rate of 80.91 % in vivo, which is significantly higher than that of unique PDT (31.78 %) or BBM (11.29 %) treatment and demonstrates the potential of our strategy for improved cancer treatment.

Ferroptosis in Cancer Therapy: Mechanisms, Small Molecule Inducers, and Novel Approaches

Ferroptosis, a unique form of programmed cell death, is initiated by an excess of iron accumulation and lipid peroxidation-induced damage. There is a growing body of evidence indicating that ferroptosis plays a critical role in the advancement of tumors. The increased metabolic activity and higher iron levels in tumor cells make them particularly vulnerable to ferroptosis. As a result, the targeted induction of ferroptosis is becoming an increasingly promising approach for cancer treatment. This review offers an overview of the regulatory mechanisms of ferroptosis, delves into the mechanism of action of traditional small molecule ferroptosis inducers and their effects on various tumors. In addition, the latest progress in inducing ferroptosis using new means such as proteolysis-targeting chimeras (PROTACs), photodynamic therapy (PDT), sonodynamic therapy (SDT) and nanomaterials is summarized. Finally, this review discusses the challenges and opportunities in the development of ferroptosis-inducing agents, focusing on discovering new targets, improving selectivity, and reducing toxic and side effects.

The role and mechanism of cinnamaldehyde in cancer

As cancer continues to rise globally, there is growing interest in discovering novel methods for prevention and treatment. Due to the limitations of traditional cancer therapies, there has been a growing emphasis on investigating herbal remedies and exploring their potential synergistic effects when combined with chemotherapy drugs. Cinnamaldehyde, derived from cinnamon, has gained significant attention for its potential role in cancer prevention and treatment. Extensive research has demonstrated that cinnamaldehyde exhibits promising anticancer properties by modulating various cellular processes involved in tumor growth and progression. However, challenges and unanswered questions remain regarding the precise mechanisms for its effective use as an anticancer agent. This article aims to explore the multifaceted effects of cinnamaldehyde on cancer cells and shed light on these existing issues. Cinnamaldehyde has diverse anti-cancer mechanisms, including inducing apoptosis by activating caspases and damaging mitochondrial function, inhibiting tumor angiogenesis, anti-proliferation, anti-inflammatory and antioxidant. In addition, cinnamaldehyde also acts as a reactive oxygen species scavenger, reducing oxidative stress and preventing DNA damage and genomic instability. This article emphasizes the promising therapeutic potential of cinnamaldehyde in cancer treatment and underscores the need for future research to unlock novel mechanisms and strategies for combating cancer. By providing valuable insights into the role and mechanism of cinnamaldehyde in cancer, this comprehensive understanding paves the way for its potential as a novel therapeutic agent. Overall, cinnamaldehyde holds great promise as an anticancer agent, and its comprehensive exploration in this article highlights its potential as a valuable addition to cancer treatment options.

Pharmacological Activities, Therapeutic Effects, and Mechanistic Actions of Trigonelline

Trigonelline (TRG) is a natural polar hydrophilic alkaloid that is found in many plants such as green coffee beans and fenugreek seeds. TRG potentially acts on multiple molecular targets, including nuclear factor erythroid 2-related factor 2 (Nrf2), peroxisome proliferator-activated receptor γ, glycogen synthase kinase, tyrosinase, nerve growth factor, estrogen receptor, amyloid-β peptide, and several neurotransmitter receptors. In this review, we systematically summarize the pharmacological activities, medicinal properties, and mechanistic actions of TRG as a potential therapeutic agent. Mechanistically, TRG can facilitate the maintenance and restoration of the metabolic homeostasis of glucose and lipids. It can counteract inflammatory constituents at multiple levels by hampering pro-inflammatory factor release, alleviating inflammatory propagation, and attenuating tissue injury. It concurrently modulates oxidative stress by the blockage of the detrimental Nrf2 pathway when autophagy is impaired. Therefore, it exerts diverse therapeutic effects on a variety of pathological conditions associated with chronic metabolic diseases and age-related disorders. It shows multidimensional effects, including neuroprotection from neurodegenerative disorders and diabetic peripheral neuropathy, neuromodulation, mitigation of cardiovascular disorders, skin diseases, diabetic mellitus, liver and kidney injuries, and anti-pathogen and anti-tumor activities. Further validations are required to define its specific targeting molecules, dissect the underlying mechanistic networks, and corroborate its efficacy in clinical trials.

Natural products targeting the MAPK-signaling pathway in cancer: overview

PURPOSE

This article summarizes natural products that target the MAPK-signaling pathway in cancer therapy. The classification, chemical structures, and anti-cancer mechanisms of these natural products are elucidated, and comprehensive information is provided on their potential use in cancer therapy.

METHODS

Using the PubMed database, we searched for keywords, including "tumor", "cancer", "natural product", "phytochemistry", "plant chemical components", and "MAPK-signaling pathway". We also screened for compounds with well-defined structures that targeting the MAPK-signaling pathway and have anti-cancer effects. We used Kingdraw software and Adobe Photoshop software to draw the chemical compound structural diagrams.

RESULTS

A total of 131 papers were searched, from which 85 compounds with well-defined structures were selected. These compounds have clear mechanisms for targeting cancer treatment and are mainly related to the MAPK-signaling pathway. Examples include eupatilin, carvacrol, oridonin, sophoridine, diosgenin, and juglone. These chemical components are classified as flavonoids, phenols, terpenoids, alkaloids, steroidal saponins, and quinones.

CONCLUSIONS

Certain MAPK pathway inhibitors have been used for clinical treatment. However, the clinical feedback has not been promising because of genomic instability, drug resistance, and side effects. Natural products have few side effects, good medicinal efficacy, a wide range of sources, individual heterogeneity of biological activity, and are capable of treating disease from multiple targets. These characteristics make natural products promising drugs for cancer treatment.

A state-of-the-art review on the NRF2 in Hepatitis virus-associated liver cancer

According to a paper released and submitted to WHO by IARC scientists, there would be 905,700 new cases of liver cancer diagnosed globally in 2020, with 830,200 deaths expected as a direct result. Hepatitis B virus (HBV) hepatitis C virus (HCV), and hepatitis D virus (HDV) all play critical roles in the pathogenesis of hepatocellular carcinoma (HCC), despite the rising prevalence of HCC due to non-infectious causes. Liver cirrhosis and HCC are devastating consequences of HBV and HCV infections, which are widespread worldwide. Associated with a high mortality rate, these infections cause about 1.3 million deaths annually and are the primary cause of HCC globally. In addition to causing insertional mutations due to viral gene integration, epigenetic alterations and inducing chronic immunological dysfunction are all methods by which these viruses turn hepatocytes into cancerous ones. While expanding our knowledge of the illness, identifying these pathways also give possibilities for novel diagnostic and treatment methods. Nuclear factor erythroid 2-related factor 2 (NRF2) activation is gaining popularity as a treatment option for oxidative stress (OS), inflammation, and metabolic abnormalities. Numerous studies have shown that elevated Nrf2 expression is linked to HCC, providing more evidence that Nrf2 is a critical factor in HCC. This aberrant Nrf2 signaling drives cell proliferation, initiates angiogenesis and invasion, and imparts drug resistance. As a result, this master regulator may be a promising treatment target for HCC. In addition, the activation of Nrf2 is a common viral effect that contributes to the pathogenesis, development, and chronicity of virus infection. However, certain viruses suppress Nrf2 activity, which is helpful to the virus in maintaining cellular homeostasis. In this paper, we discussed the influence of Nrf2 deregulation on the viral life cycle and the pathogenesis associated with HBV and HCV. We summed up the mechanisms for the modulation of Nrf2 that are deregulated by these viruses. Moreover, we describe the molecular mechanism by which Nrf2 is modulated in liver cancer, liver cancer stem cells (LCSCs), and liver cancer caused by HBV and HCV. Video Abstract.