The interplay between reactive oxygen species and antioxidants in cancer progression and therapy: a narrative review

Ansa-Ferrocene Derivatives as Potential Therapeutics

It has been known since the 1990s that the introduction of a ferrocenyl-type substituent into compounds with proven biological activity can improve their properties. More recently, it was also shown that a carbon bridge connecting the two cyclopentadienyl rings in ferrocene derivatives could enhance the biological properties of the new compounds compared to those without them. However, the synthesis of ferrocenes with this additional linker, known as ansa-ferrocenes, is more difficult due to advanced synthetic protocols and the phenomenon of planar chirality in ring-substituted compounds. As a result, research into the formation of hybrids, conjugates and other ansa-ferrocene derivatives has not been widely conducted. This review discusses the potential biological properties of these units, covering scientific articles published between 1980 and 2024.

The Interplay between Oxidative Stress and Sphingolipid Metabolism in Endometrial Cancer

Endometrial cancer is one of the most common malignancies in women. Sphingolipids, a group of lipids, play a key role in cancer biology. Cancer cells often exhibit abnormal redox homeostasis characterized by elevated levels of reactive oxygen species (ROS). Emerging evidence suggests that ceramides are involved in inhibiting proliferation and inducing apoptosis through ROS production. However, there is no data on the relationship between sphingolipid metabolism and oxidative status in endometrial cancer. The present study aims to assess the content of individual sphingolipids and oxidative status in healthy women and those with endometrial cancer. Sphingolipid analysis was performed using mass spectrometry. Total oxidative status (TOS) and total antioxidant capacity (TAC) were assessed colorimetrically. Our results showed a significant increase in the levels of all measured sphingolipids in cancer tissues compared to healthy endometrium. Additionally, a significant decrease in the S1P/ceramide ratio (sphingolipid rheostat) was observed in cancer patients, particularly for C14:0-Cer, C16:0-Cer, C18:1-Cer, C22:0-Cer, and C24:0-Cer. Furthermore, increased TOS and decreased TAC were found in cancer patients compared to healthy women. Significant correlations were observed between the levels of individual sphingolipids and oxidative status, with the strongest correlation noted between C22:0-Cer and TOS (r = 0.64). We conclude that endometrial cancer is characterized by profound changes in sphingolipid metabolism, contributing to oxidative dysregulation and tumor progression.

Use of Oleuropein and Hydroxytyrosol for Cancer Prevention and Treatment: Considerations about How Bioavailability and Metabolism Impact Their Adoption in Clinical Routine

The fact that the Mediterranean diet could represent a source of natural compounds with cancer-preventive and therapeutic activity has been the object of great interest, especially with regard to the mechanisms of action of polyphenols found in olive oil and olive leaves. Secoiridoid oleuropein (OLE) and its derivative hydroxytyrosol (3,4-dihydroxyphenylethanol, HT) have demonstrated anti-proliferative properties against a variety of tumors and hematological malignancies both in vivo and in vitro, with measurable effects on cellular redox status, metabolism, and transcriptional activity. With this review, we aim to summarize the most up-to-date information on the potential use of OLE and HT for cancer treatment, making important considerations about OLE and HT bioavailability, OLE- and HT-mediated effects on drug metabolism, and OLE and HT dual activity as both pro- and antioxidants, likely hampering their use in clinical routine. Also, we focus on the details available on the effects of nutritionally relevant concentrations of OLE and HT on cell viability, redox homeostasis, and inflammation in order to evaluate if both compounds could be considered cancer-preventive agents or new potential chemotherapy drugs whenever their only source is represented by diet.

Oxidative Stress and Redox-Dependent Pathways in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a primary liver tumor that accounts for 2% of all cancer-related deaths worldwide yearly. It can arise from cholangiocytes of biliary tracts, peribiliary glands, and possibly from progenitor cells or even hepatocytes. CCA is characterized by high chemoresistance, aggressiveness, and poor prognosis. Potentially curative surgical therapy is restricted to a small number of patients with early-stage disease (up to 35%). Accumulating evidence indicates that CCA is an oxidative stress-driven carcinoma resulting from chronic inflammation. Oxidative stress, due to enhanced reactive oxygen species (ROS) production and/or decreased antioxidants, has been recently suggested as a key factor in cholangiocyte oncogenesis through gene expression alterations and molecular damage. However, due to different experimental models and conditions, contradictory results regarding oxidative stress in cholangiocarcinoma have been reported. The role of ROS and antioxidants in cancer is controversial due to their context-dependent ability to stimulate tumorigenesis and support cancer cell proliferation or promote cell death. On these bases, the present narrative review is focused on illustrating the role of oxidative stress in cholangiocarcinoma and the main ROS-driven intracellular pathways. Heterogeneous data about antioxidant effects on cancer development are also discussed.

Ipatasertib, an oral AKT inhibitor, in combination with carboplatin exhibits anti-proliferative effects in uterine serous carcinoma

PURPOSE

Uterine serous carcinoma (USC) exhibits worse survival rates compared to the endometrioid subtype, and there is currently no effective treatment options for recurrence of this disease after platinum-based chemotherapy. Activation of PIK3CA/AKT/mTOR signaling pathway is a common biological feature in USC.

MATERIALS AND METHODS

Ipatasertib (IPAT) is an investigational, orally administered, ATP-competitive, highly selective inhibitor of pan AKT that has demonstrated anti-proliferative activity in a variety of tumor cells and tumor models. In this study, we used IPAT, carboplatin and their combination to investigate the anti-tumor activity in SPEC-2 and ARK-1 cells.

RESULTS

Our results indicate that IPAT combined with carboplatin at low doses was more effective at reducing proliferation, inducing apoptosis and causing cellular stress than IPAT or carboplatin alone. In particular, inhibition of the PIK3CA/AKT/mTOR pathway and induction of DNA damage were involved in the synergistic inhibition by combination treatment of cell viability in USC cells treated with the combination. Furthermore, IPAT in combination with carboplatin significantly reduced cell adhesion and inhibited cell invasion.

CONCLUSIONS

These findings suggest that the combination of IPAT and carboplatin has potential clinical implications for developing new USC treatment strategies.

Doped Graphene Quantum Dots as Biocompatible Radical Scavenging Agents

Oxidative stress is proven to be a leading factor in a multitude of adverse conditions, from Alzheimer's disease to cancer. Thus, developing effective radical scavenging agents to eliminate reactive oxygen species (ROS) driving many oxidative processes has become critical. In addition to conventional antioxidants, nanoscale structures and metal-organic complexes have recently shown promising potential for radical scavenging. To design an optimal nanoscale ROS scavenging agent, we have synthesized ten types of biocompatible graphene quantum dots (GQDs) augmented with various metal dopants. The radical scavenging abilities of these novel metal-doped GQD structures were, for the first time, assessed via the DPPH, KMnO4, and RHB (Rhodamine B protectant) assays. While all metal-doped GQDs consistently demonstrate antioxidant properties higher than the undoped cores, aluminum-doped GQDs exhibit 60-95% radical scavenging ability of ascorbic acid positive control. Tm-doped GQDs match the radical scavenging properties of ascorbic acid in the KMnO4 assay. All doped GQD structures possess fluorescence imaging capabilities that enable their tracking in vitro, ensuring their successful cellular internalization. Given such multifunctionality, biocompatible doped GQD antioxidants can become prospective candidates for multimodal therapeutics, including the reduction of ROS with concomitant imaging and therapeutic delivery to cancer tumors.

Chitosan-Based Nano Systems for Natural Antioxidants in Breast Cancer Therapy

Breast cancer is a major cause of death globally, accounting for around 13% of all deaths. Chemotherapy, the common treatment for cancer, can have side effects that lead to the production of reactive oxygen species (ROS) and an increase in oxidative stress in the body. Antioxidants are important for maintaining the health of cells and helping the immune system function properly. They play a crucial role in balancing the body's internal environment. Using natural antioxidants is an alternative to mitigate the harmful effects of oxidative stress. However, around 80% of natural antioxidants have limited effectiveness when taken orally because they do not dissolve well in water or other solvents. This poor solubility affects their ability to be absorbed by the body and limits their bioavailability. One strategy that has been considered is to increase their water solubility to increase their oral bioavailability. Chitosan-based nanoparticle (CSNP) systems have been extensively explored due to their reliability and simpler synthesis routes. This review focuses on the various methods of chitosan-based nanoformulation for developing effective oral dosage forms for natural antioxidants based on the pharmacokinetics and pharmacodynamics properties. Chitosan (CS) could be a model, because of its wide use in polymeric NPs research, thus providing a better understanding of the role of vehicles that carry natural antioxidants in maintaining the stability and enhancing the performance of cancer drugs.

Unraveling the Peculiar Features of Mitochondrial Metabolism and Dynamics in Prostate Cancer

Prostate cancer (PCa) is the second leading cause of cancer deaths among men in Western countries. Mitochondria, the "powerhouse" of cells, undergo distinctive metabolic and structural dynamics in different types of cancer. PCa cells experience peculiar metabolic changes during their progression from normal epithelial cells to early-stage and, progressively, to late-stage cancer cells. Specifically, healthy cells display a truncated tricarboxylic acid (TCA) cycle and inefficient oxidative phosphorylation (OXPHOS) due to the high accumulation of zinc that impairs the activity of m-aconitase, the enzyme of the TCA cycle responsible for the oxidation of citrate. During the early phase of cancer development, intracellular zinc levels decrease leading to the reactivation of m-aconitase, TCA cycle and OXPHOS. PCa cells change their metabolic features again when progressing to the late stage of cancer. In particular, the Warburg effect was consistently shown to be the main metabolic feature of late-stage PCa cells. However, accumulating evidence sustains that both the TCA cycle and the OXPHOS pathway are still present and active in these cells. The androgen receptor axis as well as mutations in mitochondrial genes involved in metabolic rewiring were shown to play a key role in PCa cell metabolic reprogramming. Mitochondrial structural dynamics, such as biogenesis, fusion/fission and mitophagy, were also observed in PCa cells. In this review, we focus on the mitochondrial metabolic and structural dynamics occurring in PCa during tumor development and progression; their role as effective molecular targets for novel therapeutic strategies in PCa patients is also discussed.

The Major Stilbene Compound Accumulated in the Roots of a Resistant Variety of Phoenix dactylifera L. Activates Proteasome for a Path in Anti-Aging Strategy

The main objective of the present study is to estimate, through differential analysis, various biological activities of total phenolics content in alcoholic extracts of three date palm varieties sensitive or resistant to Fusarium oxysporum. sp Albidinis. Here, stilbene products with antioxidant and bioactive capacities were evidenced in resistant variety Taabdount (TAAR). Furthermore, the methanolic fraction of the TAAR-resistant date palm variety contains a significant product, determined by LC-MS/MS and 1H, 13C NMR, belonging to the family of hydroxystilbenes, which exhibits antioxidant capacities, inhibits the mushroom tyrosinase activity, and activates and exerts a protective effect on hypochlorite-induced damage in 20S proteasome of human dermal fibroblast aged cells. Altogether, the present results indicate that hydroxystilbene present in resistant Phoenix dactylifera L. should be studied to understand the way that the stilbene could exert anti-aging ability.

Gallic acid suppresses the progression of triple-negative breast cancer HCC1806 cells via modulating PI3K/AKT/EGFR and MAPK signaling pathways

Triple-negative breast cancer (TNBC) is a severe threat to women's health because of its aggressive nature, early age of onset, and high recurrence rate. Therefore, in this study, we aimed to evaluate the anti-tumor effects of Gallic acid (GA) on the TNBC HCC1806 cells in vitro. The cell proliferation was detected by MTT and plate clone formation assays, cell apoptosis, cell cycle, and mitochondrial membrane potential (MMP) were analyzed by flow cytometry and Hoechst 33258 staining assays, and the intracellular reactive oxygen species (ROS) accumulation were also investigated. Real-Time PCR and western blot were examined to explore the mechanism of action. The results indicated that GA suppressed HCC1806 cells proliferation and promoted HCC1806 cells apoptosis. Meanwhile, GA treatment changed the morphology of the HCC1806 cells. In addition, GA blocked the HCC1806 cells cycle in the S phase, and it induced cells apoptosis accompanied by ROS accumulation and MMP depolarization. Real-Time PCR results suggested that GA increased Bax, Caspase-3, Caspase-9, P53, JINK and P38 mRNA expression, and decreased Bcl-2, PI3K, AKT and EGFR mRNA expression. Western blotting results suggested that GA increased Bax, cleaved-Caspase-3, cleaved-Caspase-9, P53, P-ERK1/2, P-JNK, P-P38 proteins expression, and decreased Bcl-2, P-PI3K, P-AKT, P-EGFR proteins expression. Furthermore, molecular docking suggested that GA has the high affinity for PI3K, AKT, EGFR, ERK1/2, JNK, and P38. In conclusion, GA could suppress HCC1806 cells proliferation and promote HCC1806 cells apoptosis through the mitochondrial apoptosis pathway and induces ROS generation which further inhibits PI3K/AKT/EGFR and activates MAPK signaling pathways. Our study will provide some new references for using GA in the treatment of TNBC.

Identification of natural product 3, 5-diiodotyrosine as APOBEC3B inhibitor to prevent somatic mutation accumulation and cancer progression

BACKGROUND

The development of cancer is largely dependent on the accumulation of somatic mutations, indicating the potential to develop cancer chemoprevention agents targeting mutation drivers. However, ideal cancer chemoprevention agents that can effectively inhibit the mutation drivers have not been identified yet.

METHODS

The somatic mutation signatures and expression analyses of APOBEC3B were performed in patient with pan-cancer. The computer-aided screening and skeleton-based searching were performed to identify natural products that can inhibit the activity of APOBEC3B. 4-nitroquinoline-1-oxide (4-NQO)-induced spontaneous esophageal squamous cell carcinoma (ESCC) and azoxymethane/dextran sulfate sodium (AOM/DSS)-induced spontaneous colon cancer mouse models were conducted to investigate the influences of APOBEC3B inhibitor on the prevention of somatic mutation accumulation and cancer progression.

RESULTS

Here, we discovered that the cytidine deaminase APOBEC3B correlated somatic mutations were widely observed in a variety of cancers, and its overexpression indicated poor survival. SMC247 (3, 5-diiodotyrosine), as a source of kelp iodine without side effects, could strongly bind APOBEC3B (K_D=65 nM) and effectively inhibit its deaminase activity (IC₅₀=1.69 µM). Interestingly, 3, 5-diiodotyrosine could significantly reduce the clusters of mutations, prevent the precancerous lesion progression, and prolong the survival in 4-NQO-induced spontaneous ESCC and AOM/DSS-induced spontaneous colon cancer mouse models. Furthermore, 3, 5-diiodotyrosine could reduce colitis, increase the proportion and function of T lymphocytes via IL-15 in tumor microenvironment. The synergistic cancer prevention effects were observed when 3, 5-diiodotyrosine combined with PD-1/PD-L1 blockade.

CONCLUSIONS

This is the first prove-of-concept study to elucidate that the natural product 3, 5-diiodotyrosine could prevent somatic mutation accumulation and cancer progression through inhibiting the enzymatic activity of APOBEC3B. In addition, 3, 5-diiodotyrosine could reduce the colitis and increase the infiltration and function of T lymphocytes via IL-15 in tumor microenvironment. 3, 5-diiodotyrosine combined with PD-1/PD-L1 blockade could elicit synergistic cancer prevention effects, indicating a novel strategy for both prevent the somatic mutation accumulation and the immune-suppressive microenvironment exacerbation.

Molecular and Cellular Mechanisms of Propolis and Its Polyphenolic Compounds against Cancer

In recent years, interest in natural products such as alternative sources of pharmaceuticals for numerous chronic diseases, including tumors, has been renewed. Propolis, a natural product collected by honeybees, and polyphenolic/flavonoid propolis-related components modulate all steps of the cancer progression process. Anticancer activity of propolis and its compounds relies on various mechanisms: cell-cycle arrest and attenuation of cancer cells proliferation, reduction in the number of cancer stem cells, induction of apoptosis, modulation of oncogene signaling pathways, inhibition of matrix metalloproteinases, prevention of metastasis, anti-angiogenesis, anti-inflammatory effects accompanied by the modulation of the tumor microenvironment (by modifying macrophage activation and polarization), epigenetic regulation, antiviral and bactericidal activities, modulation of gut microbiota, and attenuation of chemotherapy-induced deleterious side effects. Ingredients from propolis also "sensitize" cancer cells to chemotherapeutic agents, likely by blocking the activation of the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). In this review, we summarize the current knowledge related to the the effects of flavonoids and other polyphenolic compounds from propolis on tumor growth and metastasizing ability, and discuss possible molecular and cellular mechanisms involved in the modulation of inflammatory pathways and cellular processes that affect survival, proliferation, invasion, angiogenesis, and metastasis of the tumor.