Vitamin C selectively kills KRAS and BRAF mutant colorectal cancer cells by targeting GAPDH

Targeting the redox vulnerability of acute myeloid leukaemia cells with a combination of auranofin and vitamin C

Acute myeloid leukaemia (AML) is a heterogeneous disease characterized by complex molecular and cytogenetic abnormalities. Pro-oxidant cellular redox status is a common hallmark of AML cells, providing a rationale for redox-based anticancer strategy. We previously discovered that auranofin (AUF), initially used for the treatment of rheumatoid arthritis and repositioned for its anticancer activity, can synergize with a pharmacological concentration of vitamin C (VC) against breast cancer cell line models. In this study, we observed that this drug combination synergistically and efficiently killed cells of leukaemic cell lines established from different myeloid subtypes. In addition to an induced elevation of reactive oxygen species and ATP depletion, a rapid dephosphorylation of 4E-BP1 and p70S6K, together with a strong inhibition of protein synthesis were early events in response to AUF/VC treatment, suggesting their implication in AUF/VC-induced cytotoxicity. Importantly, a study on 22 primary AML specimens from various AML subtypes showed that AUF/VC combinations at pharmacologically achievable concentrations were effective to eradicate primary leukaemic CD34+ cells from the majority of these samples, while being less toxic to normal cord blood CD34+ cells. Our findings indicate that targeting the redox vulnerability of AML with AUF/VC combinations could present a potential anti-AML therapeutic approach.

Redox-active vitamin C suppresses human osteosarcoma growth by triggering intracellular ROS-iron-calcium signaling crosstalk and mitochondrial dysfunction

Pharmacological vitamin C (VC) has gained attention for its pro-oxidant characteristics and selective ability to induce cancer cell death. However, defining its role in cancer has been challenging due to its complex redox properties. In this study, using a human osteosarcoma (OS) model, we show that the redox-active property of VC is critical for inducing non-apoptotic cancer cell death via intracellular reactive oxygen species (ROS)-iron-calcium crosstalk and mitochondrial dysfunction. In both 2D and 3D OS cell culture models, only the oxidizable form of VC demonstrated potent dose-dependent cytotoxicity, while non-oxidizable and oxidized VC derivatives had minimal effects. Live-cell imaging showed that only oxidizable VC caused a surge in cytotoxic ROS, dependent on iron rather than copper. Inhibitors of ferroptosis, a form of iron-dependent cell death, along with classical apoptosis inhibitors, were unable to completely counteract the cytotoxic effects induced by VC. Further pharmacological and genetic inhibition analyses showed that VC triggers calcium release through inositol 1,4,5-trisphosphate receptors (IP3Rs), leading to mitochondrial ROS production and eventual cell death. RNA sequencing revealed down-regulation of genes involved in the mitochondrial electron transport chain and oxidative phosphorylation upon pharmacological VC treatment. Consistently, high-dose VC reduced mitochondrial membrane potential, oxidative phosphorylation, and ATP levels, with ATP reconstitution rescuing VC-induced cytotoxicity. In vivo OS xenograft studies demonstrated reduced tumor growth with high-dose VC administration, concomitant with the altered expression of mitochondrial ATP synthase (MT-ATP). These findings emphasize VC's potential clinical utility in osteosarcoma treatment by inducing mitochondrial metabolic dysfunction through a vicious intracellular ROS-iron-calcium cycle.

Cyclic fasting-mimicking diet in cancer treatment: Preclinical and clinical evidence

In preclinical tumor models, cyclic fasting and fasting-mimicking diets (FMDs) produce antitumor effects that become synergistic when combined with a wide range of standard anticancer treatments while protecting normal tissues from treatment-induced adverse events. More recently, results of phase 1/2 clinical trials showed that cyclic FMD is safe, feasible, and associated with positive metabolic and immunomodulatory effects in patients with different tumor types, thus paving the way for larger clinical trials to investigate FMD anticancer activity in different clinical contexts. Here, we review the tumor-cell-autonomous and immune-system-mediated mechanisms of fasting/FMD antitumor effects, and we critically discuss new metabolic interventions that could synergize with nutrient starvation to boost its anticancer activity and prevent or reverse tumor resistance while minimizing toxicity to patients. Finally, we highlight potential future applications of FMD approaches in combination with standard anticancer strategies as well as strategies to implement the design and conduction of clinical trials.

Glucose-6-phosphate dehydrogenase maintains redox homeostasis and biosynthesis in LKB1-deficient KRAS-driven lung cancer

Cancer cells depend on nicotinamide adenine dinucleotide phosphate (NADPH) to combat oxidative stress and support reductive biosynthesis. One major NADPH production route is the oxidative pentose phosphate pathway (committed step: glucose-6-phosphate dehydrogenase, G6PD). Alternatives exist and can compensate in some tumors. Here, using genetically-engineered lung cancer mouse models, we show that G6PD ablation significantly suppresses KrasG12D/+;Lkb1-/- (KL) but not KrasG12D/+;P53-/- (KP) lung tumorigenesis. In vivo isotope tracing and metabolomics reveal that G6PD ablation significantly impairs NADPH generation, redox balance, and de novo lipogenesis in KL but not KP lung tumors. Mechanistically, in KL tumors, G6PD ablation activates p53, suppressing tumor growth. As tumors progress, G6PD-deficient KL tumors increase an alternative NADPH source from serine-driven one carbon metabolism, rendering associated tumor-derived cell lines sensitive to serine/glycine depletion. Thus, oncogenic driver mutations determine lung cancer dependence on G6PD, whose targeting is a potential therapeutic strategy for tumors harboring KRAS and LKB1 co-mutations.

Targeting Metabolic-Redox Nexus to Regulate Drug Resistance: From Mechanism to Tumor Therapy

Drug resistance is currently one of the biggest challenges in cancer treatment. With the deepening understanding of drug resistance, various mechanisms have been revealed, including metabolic reprogramming and alterations of redox balance. Notably, metabolic reprogramming mediates the survival of tumor cells in harsh environments, thereby promoting the development of drug resistance. In addition, the changes during metabolic pattern shift trigger reactive oxygen species (ROS) production, which in turn regulates cellular metabolism, DNA repair, cell death, and drug metabolism in direct or indirect ways to influence the sensitivity of tumors to therapies. Therefore, the intersection of metabolism and ROS profoundly affects tumor drug resistance, and clarifying the entangled mechanisms may be beneficial for developing drugs and treatment methods to thwart drug resistance. In this review, we will summarize the regulatory mechanism of redox and metabolism on tumor drug resistance and highlight recent therapeutic strategies targeting metabolic-redox circuits, including dietary interventions, novel chemosynthetic drugs, drug combination regimens, and novel drug delivery systems.

Pharmacologic ascorbate induces transient hypoxia sensitizing pancreatic ductal adenocarcinoma to a hypoxia activated prodrug

Hypoxic tumor microenvironments pose a significant challenge in cancer treatment. Hypoxia-activated prodrugs like evofosfamide aim to specifically target and eliminate these resistant cells. However, their effectiveness is often limited by reoxygenation after cell death. We hypothesized that ascorbate's pro-oxidant properties could be harnessed to induce transient hypoxia, enhancing the efficacy of evofosfamide by overcoming reoxygenation. To test this hypothesis, we investigated the sensitivity of MIA Paca-2 and A549 cancer cells to ascorbate in vitro and in vivo. Ascorbate induced a cytotoxic effect at 5 mM that could be alleviated by endogenous administration of catalase, suggesting a role for hydrogen peroxide in its cytotoxic mechanism. In vitro, Seahorse experiments indicated that the generation of hydrogen peroxide consumes oxygen, which is offset at later time points by a reduction in oxygen consumption due to hydrogen peroxide's cytotoxic effect. In vivo, photoacoustic imaging showed pharmacologic ascorbate treatment at sublethal levels triggered a complex, multi-phasic response in tumor oxygenation across both cell lines. Initially, ascorbate generated transient hypoxia within minutes through hydrogen peroxide production, via reactions that consume oxygen. This initial hypoxic phase peaked at around 150 s and then gradually subsided. However, at longer time scales (approximately 300 s) a vasodilation effect triggered by ascorbate resulted in increased blood flow and subsequent reoxygenation. Combining sublethal levels of i. p. Ascorbate with evofosfamide significantly prolonged tumor doubling time in MIA Paca-2 and A549 xenografts compared to either treatment alone. This improvement, however, was only observed in a subpopulation of tumors, highlighting the complexity of the oxygenation response.

Rapid redox-response featured visual ascorbic acid sensor based on simple-assembled europium metal-organic framework

A facile, fast and visible sensing platform for ascorbic acid (AA) detection has been developed based on self-assembled hydrangea-like europium metal-organic framework (HL-EuMOF). HL-EuMOF was synthesized through a simple one-step mixing process with Eu3+ and 1, 10-phenanthroline-2, 9-dicarboxylic acid at room temperature, which exhibited excellent properties including strong red fluorescence, long decay lifetime (548.623 μs) and good luminescent stability. Based on the specific redox reaction between Fe3+ and AA, the HL-EuMOF@Fe3+ was fabricated with "turn-off" response for AA, where the resulting Fe2+ displayed effective fluorescence quenching ability toward HL-EuMOF. The sensor demonstrated low detection limit (31.94 nM), rapid response time (30 s) and high selectivity. Integration of smartphone-assisted RGB analysis with HL-EuMOF@Fe3+ permitted convenient and visible quantitative determination of AA level. This approach also presented good detection performances in complex human serum and beverage samples, which could provide a valuable tool for AA detection in biomedical research and food industry.

Empowering γδ T-cell functionality with vitamin C

Vitamin C (ascorbic acid) is a potent antioxidant and a cofactor for various enzymes including histone demethylases and methylcytosine dioxygenases. Vitamin C also exerts direct cytotoxicity toward selected tumor cells including colorectal carcinoma. Moreover, vitamin C has been shown to impact immune cell differentiation at various levels including maturation and/or functionality of T cells and their progenitors, dendritic cells, B cells, and NK cells. γδ T cells have recently attracted great interest as effector cells for cell-based cancer immunotherapy, due to their HLA-independent recognition of a large variety of tumor cells. While γδ T cells can thus be also applied as an allogeneic off-the-shelf product, it is obvious that the effector function of γδ T cells needs to be optimized to ensure the best possible clinical efficacy. Here we review the immunomodulatory mechanisms of vitamin C with a special focus on how vitamin C enhances the effector function of γδ T cells. We also discuss future directions of how vitamin C can be used in the clinical setting to boost the efficacy of adoptive cell therapies.

Improving both performance and stability of n-type organic semiconductors by vitamin C

Organic semiconductors (OSCs) are one of the most promising candidates for flexible, wearable and large-area electronics. However, the development of n-type OSCs has been severely held back due to the poor stability of their most candidates, that is, the intrinsically high reactivity of negatively charged polarons to oxygen and water. Here we demonstrate a general strategy based on vitamin C to stabilize n-type OSCs, remarkably improving the performance and stability of their device, for example, organic field-effect transistors. Vitamin C scavenges reactive oxygen species and inhibits their generation by sacrificial oxidation and non-sacrificial triplet quenching in a cascade process, which not only lastingly prevents molecular structure from oxidation damage but also passivates the latent electron traps to stabilize electron transport. This study presents a way to overcome the long-standing stability problem of n-type OSCs and devices.

Post-diagnostic multivitamin supplement use and colorectal cancer survival: A prospective cohort study

BACKGROUND

Use of multivitamin supplements has been associated with lower incidence of colorectal cancer (CRC). However, its influence on CRC survival remains unknown.

METHODS

Among 2424 patients with stage I-III CRC who provided detailed information about multivitamin supplements in the Nurses' Health Study and Health Professionals Follow-up Study, the authors calculated multivariable hazard ratios (HRs) of multivitamin supplements for all-cause and CRC-specific mortality according to post-diagnostic use and dose of multivitamin supplements.

RESULTS

During a median follow-up of 11 years, the authors documented 1512 deaths, among which 343 were of CRC. Compared to non-users, post-diagnostic users of multivitamin supplements at a dose of 3-5 tablets/week had lower CRC-specific mortality (HR, 0.55; 95% confidence interval [CI], 0.36-0.83, p = .005), and post-diagnostic users at doses of 3-5 and 6-9 tablets/week had lower all-cause mortality (HR, 0.81; 95% CI, 0.67-0.99, p = .04; HR, 0.79; 95% CI, 0.70-0.88), p < .001). The dose-response analysis showed a curvilinear relationship for both CRC-specific (pnonlinearity < .001) and all-cause mortality (pnonlinearity = .004), with the maximum risk reduction observed at 3-5 tablets/week and no further reduction at higher doses. Compared to non-users in both pre- and post-diagnosis periods, new post-diagnostic users at dose of <10 tablets/week had a lower all-cause mortality (HR, 0.81; 95% CI, 0.71-0.94, p = .005), whereas new users at a dose of ≥10 tablets/week (HR, 1.58; 95% CI, 1.07-2.33) and discontinued users (HR, 1.35; 95% CI, 1.14-1.59) had a higher risk of mortality.

CONCLUSIONS

Use of multivitamin supplements at a moderate dose after a diagnosis of nonmetastatic CRC is associated with lower CRC-specific and overall mortality, whereas a high dose (≥10 tablets/week) use is associated with higher CRC-specific mortality.

Role of dietary nutrients and metabolism in colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies and the leading causes of cancer related deaths worldwide. The development of CRC is driven by a combination of genetic and environmental factors. There is growing evidence that changes in dietary nutrition may modulate the CRC risk, and protective effects on the risk of developing CRC have been advocated for specific nutrients such as glucose, amino acids, lipid, vitamins, micronutrients and prebiotics. Metabolic crosstalk between tumor cells, tumor microenvironment components and intestinal flora further promote proliferation, invasion and metastasis of CRC cells and leads to treatment resistance. This review summarizes the research progress on CRC prevention, pathogenesis, and treatment by dietary supplementation or deficiency of glucose, amino acids, lipids, vitamins, micronutri-ents, and prebiotics, respectively. The roles played by different nutrients and dietary crosstalk in the tumor microenvironment and metabolism are discussed, and nutritional modulation is inspired to be beneficial in the prevention and treatment of CRC.

The discovery of an anti-Candida xanthone with selective inhibition of Candida albicans GAPDH

OBJECTIVES

This study aimed to discover novel antifungals targeting Candida albicans glyceraldehyde-3-phosphate dehydrogenase (CaGAPDH), have an insight into inhibitory mode, and provide evidence supporting CaGAPDH as a target for new antifungals.

METHODS

Virtual screening was utilized to discover inhibitors of CaGAPDH. The inhibitory effect on cellular GAPDH was evaluated by determining the levels of ATP, NAD, NADH, etc., as well as examining GAPDH mRNA and protein expression. The role of GAPDH inhibition in C. albicans was supported by drug affinity responsive target stability and overexpression experiments. The mechanism of CaGAPDH inhibition was elucidated by Michaelis-Menten enzyme kinetics and site-specific mutagenesis based on docking. Chemical synthesis was used to produce an improved candidate. Different sources of GAPDH were used to evaluate inhibitory selectivity across species. In vitro and in vivo antifungal tests, along with anti-biofilm activity, were carried out to evaluate antifungal potential of GAPDH inhibitors.

RESULTS

A natural xanthone was identified as the first competitive inhibitor of CaGAPDH. It demonstrated in vitro anti-C. albicans potential but also caused hemolysis. XP-W, a synthetic side-chain-optimized xanthone, demonstrated a better safety profile, exhibiting a 50-fold selectivity for CaGAPDH over human GAPDH. XP-W also exhibited potent anti-biofilm activity and displayed broad-spectrum anti-Candida activities in vitro and in vivo, including multi-azole-resistant C. albicans.

CONCLUSIONS

These results demonstrate for the first time that CaGAPDH is a valuable target for antifungal drug discovery, and XP-W provides a promising lead.

The Involvement of Ascorbic Acid in Cancer Treatment

Vitamin C (VC), also known as ascorbic acid, plays a crucial role as a water-soluble nutrient within the human body, contributing to a variety of metabolic processes. Research findings suggest that increased doses of VC demonstrate potential anti-tumor capabilities. This review delves into the mechanisms of VC absorption and its implications for cancer management. Building upon these foundational insights, we explore modern delivery systems for VC, evaluating its use in diverse cancer treatment methods. These include starvation therapy, chemodynamic therapy (CDT), photothermal/photodynamic therapy (PTT/PDT), electrothermal therapy, immunotherapy, cellular reprogramming, chemotherapy, radiotherapy, and various combination therapies.

Several lines of antioxidant defense against oxidative stress: antioxidant enzymes, nanomaterials with multiple enzyme-mimicking activities, and low-molecular-weight antioxidants

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are well recognized for playing a dual role, since they can be either deleterious or beneficial to biological systems. An imbalance between ROS production and elimination is termed oxidative stress, a critical factor and common denominator of many chronic diseases such as cancer, cardiovascular diseases, metabolic diseases, neurological disorders (Alzheimer's and Parkinson's diseases), and other disorders. To counteract the harmful effects of ROS, organisms have evolved a complex, three-line antioxidant defense system. The first-line defense mechanism is the most efficient and involves antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). This line of defense plays an irreplaceable role in the dismutation of superoxide radicals (O2•-) and hydrogen peroxide (H2O2). The removal of superoxide radicals by SOD prevents the formation of the much more damaging peroxynitrite ONOO- (O2•-  + NO• → ONOO-) and maintains the physiologically relevant level of nitric oxide (NO•), an important molecule in neurotransmission, inflammation, and vasodilation. The second-line antioxidant defense pathway involves exogenous diet-derived small-molecule antioxidants. The third-line antioxidant defense is ensured by the repair or removal of oxidized proteins and other biomolecules by a variety of enzyme systems. This review briefly discusses the endogenous (mitochondria, NADPH, xanthine oxidase (XO), Fenton reaction) and exogenous (e.g., smoking, radiation, drugs, pollution) sources of ROS (superoxide radical, hydrogen peroxide, hydroxyl radical, peroxyl radical, hypochlorous acid, peroxynitrite). Attention has been given to the first-line antioxidant defense system provided by SOD, CAT, and GPx. The chemical and molecular mechanisms of antioxidant enzymes, enzyme-related diseases (cancer, cardiovascular, lung, metabolic, and neurological diseases), and the role of enzymes (e.g., GPx4) in cellular processes such as ferroptosis are discussed. Potential therapeutic applications of enzyme mimics and recent progress in metal-based (copper, iron, cobalt, molybdenum, cerium) and nonmetal (carbon)-based nanomaterials with enzyme-like activities (nanozymes) are also discussed. Moreover, attention has been given to the mechanisms of action of low-molecular-weight antioxidants (vitamin C (ascorbate), vitamin E (alpha-tocopherol), carotenoids (e.g., β-carotene, lycopene, lutein), flavonoids (e.g., quercetin, anthocyanins, epicatechin), and glutathione (GSH)), the activation of transcription factors such as Nrf2, and the protection against chronic diseases. Given that there is a discrepancy between preclinical and clinical studies, approaches that may result in greater pharmacological and clinical success of low-molecular-weight antioxidant therapies are also subject to discussion.

Application of Nanomaterial-Based Sonodynamic Therapy in Tumor Therapy

Sonodynamic therapy (SDT) has attracted significant attention in recent years as it is an innovative approach to tumor treatment. It involves the utilization of sound waves or ultrasound (US) to activate acoustic sensitizers, enabling targeted drug release for precise tumor treatment. This review aims to provide a comprehensive overview of SDT, encompassing its underlying principles and therapeutic mechanisms, the applications of nanomaterials, and potential synergies with combination therapies. The review begins by introducing the fundamental principle of SDT and delving into the intricate mechanisms through which it facilitates tumor treatment. A detailed analysis is presented, outlining how SDT effectively destroys tumor cells by modulating drug release mechanisms. Subsequently, this review explores the diverse range of nanomaterials utilized in SDT applications and highlights their specific contributions to enhancing treatment outcomes. Furthermore, the potential to combine SDT with other therapeutic modalities such as photothermal therapy (PTT) and chemotherapy is discussed. These combined approaches aim to synergistically improve therapeutic efficacy while mitigating side effects. In conclusion, SDT emerges as a promising frontier in tumor treatment that offers personalized and effective treatment options with the potential to revolutionize patient care. As research progresses, SDT is poised to play a pivotal role in shaping the future landscape of oncology by providing patients with a broader spectrum of efficacious and tailored treatment options.

Ascorbyl palmitate ameliorates inflammatory diseases by inhibition of NLRP3 inflammasome

The aberrant activation of NLRP3 inflammasome contributes to pathogenesis of multiple inflammation-driven human diseases. However, the medications targeting NLRP3 inflammasome are not approved for clinic use to date. Here, we show that ascorbyl palmitate (AP), a lipophilic derivative of ascorbic acid (AA) and a safe food additive, is a potent inhibitor of NLRP3 inflammasome. Compared with AA, AP inhibited the activation of NLRP3 inflammasome with increased potency and specificity. Mechanistically, AP directly scavenged mitochondrial reactive oxygen species (mitoROS) by its antioxidant activity and blocked NLRP3-NEK7 interaction and NLRP3 inflammasome assembly. Moreover, AP showed more significant preventive effects than AA in LPS-induced systemic inflammation, dextran sulfate sodium (DSS)-induced colitis and experimental autoimmune encephalomyelitis (EAE). Thus, our results suggest that AP is a potential therapeutic combating NLRP3-driven diseases.

Targeted Metabolomics Highlights Dramatic Antioxidant Depletion, Increased Oxidative/Nitrosative Stress and Altered Purine and Pyrimidine Concentrations in Serum of Primary Myelofibrosis Patients

To date, little is known concerning the circulating levels of biochemically relevant metabolites (antioxidants, oxidative/nitrosative stress biomarkers, purines, and pyrimidines) in patients with primary myelofibrosis (PMF), a rare form of myeloproliferative tumor causing a dramatic decrease in erythropoiesis and angiogenesis. In this study, using a targeted metabolomic approach, serum samples of 22 PMF patients and of 22 control healthy donors were analyzed to quantify the circulating concentrations of hypoxanthine, xanthine, uric acid (as representative purines), uracil, β-pseudouridine, uridine (as representative pyrimidines), reduced glutathione (GSH), ascorbic acid (as two of the main water-soluble antioxidants), malondialdehyde, nitrite, nitrate (as oxidative/nitrosative stress biomarkers) and creatinine, using well-established HPLC method for their determination. Results showed that PMF patients have dramatic depletions of both ascorbic acid and GSH (37.3- and 3.81-times lower circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001), accompanied by significant increases in malondialdehyde (MDA) and nitrite + nitrate (4.73- and 1.66-times higher circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001). Additionally, PMF patients have remarkable alterations of circulating purines, pyrimidines, and creatinine, suggesting potential mitochondrial dysfunctions causing energy metabolism imbalance and consequent increases in these cell energy-related compounds. Overall, these results, besides evidencing previously unknown serum metabolic alterations in PMF patients, suggest that the determination of serum levels of the aforementioned compounds may be useful to evaluate PMF patients on hospital admission for adjunctive therapies aimed at recovering their correct antioxidant status, as well as to monitor patients' status and potential pharmacological treatments.

High-dose ascorbate exerts anti-tumor activities and improves inhibitory effect of carboplatin through the pro-oxidant function pathway in uterine serous carcinoma cell lines

OBJECTIVE

Uterine serous carcinoma is a highly aggressive non-endometrioid subtype of endometrial cancer with poor survival rates overall, creating a strong need for new therapeutic strategies to improve outcomes. High-dose ascorbate (vitamin C) has been shown to inhibit cell proliferation and tumor growth in multiple preclinical models and has shown promising anti-tumor activity in combination with chemotherapy, with a favorable safety profile. We aimed to study the anti-tumor effects of ascorbate and its synergistic effect with carboplatin on uterine serous carcinoma cells.

METHODS

Cell proliferation was evaluated by MTT and colony formation assays in ARK1, ARK2 and SPEC2 cells. Cellular stress, antioxidant ability, cleaved caspase 3 activity and adhesion were measured by ELISA assays. Cell cycle was detected by Cellometer. Invasion was measured using a wound healing assay. Changes in protein expression were determined by Western immunoblotting.

RESULTS

High-dose ascorbate significantly inhibited cell proliferation, caused cell cycle arrest, induced cellular stress, and apoptosis, increased DNA damage, and suppressed cell invasion in ARK1 and SPEC2 cells. Treatment of both cells with 1 mM N-acetylcysteine reversed ascorbate-induced apoptosis and inhibition of cell proliferation. The combination of ascorbate and carboplatin produced significant synergistic effects in inhibiting cell proliferation and invasion, inducing cellular stress, causing DNA damage, and enhancing cleaved caspase 3 levels compared to each compound alone in both cells.

CONCLUSIONS

Ascorbate has potent antitumor activity and acts synergistically with carboplatin through its pro-oxidant effects. Clinical trials of ascorbate combined with carboplatin as adjuvant treatment of uterine serous carcinoma are worth exploring.

The pleiotropic functions of reactive oxygen species in cancer

Cellular redox homeostasis is an essential, dynamic process that ensures the balance between reducing and oxidizing reactions within cells and thus has implications across all areas of biology. Changes in levels of reactive oxygen species can disrupt redox homeostasis, leading to oxidative or reductive stress that contributes to the pathogenesis of many malignancies, including cancer. From transformation and tumor initiation to metastatic dissemination, increasing reactive oxygen species in cancer cells can paradoxically promote or suppress the tumorigenic process, depending on the extent of redox stress, its spatiotemporal characteristics and the tumor microenvironment. Here we review how redox regulation influences tumorigenesis, highlighting therapeutic opportunities enabled by redox-related alterations in cancer cells.

Vitamin C Inhibited Pulmonary Metastasis through Activating Nrf2/HO-1 Pathway

As an important nutritional component, vitamin C (Vc) shows good antitumor activity in a variety of cancer, but there are few studies in pulmonary metastasis. In order to verify its anticancer and antimetastatic effect, the study sets up H22 pulmonary metastasis mouse model. The results show that intraperitoneal injection of Vc inhibits pulmonary metastasis through up-regulating the expression of Nrf2, HO-1, cleaved caspases 3 and 9, and causing DNA damage and apoptosis which is similar to the pro-oxidant effect of Vc in p53 null cells (H1299 cells). Meanwhile, oral administration of Vc up-regulates the expression of p53, directly activates Nrf2/HO-1 pathway, increases expression of cleaved caspases 3 and 9, and ultimately inhibits pulmonary metastasis, which is the same as the antioxidant result of Vc in p53 wild-type cells. In addition, Vc inhibits the proliferation and migration of lung cancer cells in a concentration-dependent manner and has little cytotoxic effects on normal cells. Notably, the experiment further illustrates that besides intravenous Vc, oral Vc significantly inhibits the pulmonary metastasis in mice. All in all, these findings provide new clues for Vc-treated pulmonary metastasis in clinical research.

Structure of glyceraldehyde-3-phosphate dehydrogenase from Paracoccidioides lutzii in complex with an aldonic sugar acid

The pathogen Paracoccidioides lutzii (Pb01) is found in South America countries Colombia, Ecuador, Venezuela and Brazil, especially in the central, west, and north regions of the latter. It belongs to the Ajellomycetaceae family, Onygenales order, and is typically thermodimorphic, presenting yeast cells when it grows in animal tissues, but mycelia when in the environment, where it produces the infectious propagule. This fungus is one of the etiologic agents of Paracoccidioidomycosis (PCM), the most important endemic fungal infection in Latin America. Investigations on its genome have contributed to a better understanding about its metabolism and revealed the complexity of several metabolic glycolytic pathways. Glyceraldehyde-3-Phosphate Dehydrogenase from Paracoccidioides lutzii (PlGAPDH) is considered a moonlighting protein and participates in several biological processes of this pathogen. The enzyme was expressed and purified, as seen in SDS-PAGE gel, crystallized and had its three dimensional structure (3D) determined in complex with NAD+, a sulphate ion and d-galactonic acid, therefore, a type of 'GAA site'. It is the first GAPDH structure to show this chemical type in this site and how this protein can bind an acid derived from oxidation of a linear hexose.

Vitamin-C-dependent downregulation of the citrate metabolism pathway potentiates pancreatic ductal adenocarcinoma growth arrest

In pancreatic ductal adenocarcinoma (PDAC), metabolic rewiring and resistance to standard therapy are closely associated. PDAC cells show enormous requirements for glucose-derived citrate, the first rate-limiting metabolite in the synthesis of new lipids. Both the expression and activity of citrate synthase (CS) are extraordinarily upregulated in PDAC. However, no previous relationship between gemcitabine response and citrate metabolism has been documented in pancreatic cancer. Here, we report for the first time that pharmacological doses of vitamin C are capable of exerting an inhibitory action on the activity of CS, reducing glucose-derived citrate levels. Moreover, ascorbate targets citrate metabolism towards the de novo lipogenesis pathway, impairing fatty acid synthase (FASN) and ATP citrate lyase (ACLY) expression. Lowered citrate availability was found to be directly associated with diminished proliferation and, remarkably, enhanced gemcitabine response. Moreover, the deregulated citrate-derived lipogenic pathway correlated with a remarkable decrease in extracellular pH through inhibition of lactate dehydrogenase (LDH) and overall reduced glycolytic metabolism. Modulation of citric acid metabolism in highly chemoresistant pancreatic adenocarcinoma, through molecules such as vitamin C, could be considered as a future clinical option to improve patient response to standard chemotherapy regimens.

The Vitamin C Enantiomers Possess a Comparable Potency in the Induction of Oxidative Stress in Cancer Cells but Differ in Their Toxicity

The use of vitamin C (VC) in high doses demonstrates a potent tumor suppressive effect by mediating a glucose-dependent oxidative stress in Kirsten rat sarcoma (KRAS) mutant cancer cells. VC with arsenic trioxide (ATO) is a promising drug combination that might lead to the development of effective cancer therapeutics. Considering that a tumor suppressive effect of VC requires its high-dose administration, it is of interest to examine the toxicity of two enantiomers of VC (enantiomer d-optical isomer D-VC and natural l-optical isomer L-VC) in vitro and in vivo. We show that the combinations of L-VC with ATO and D-VC with ATO induced a similar cytotoxic oxidative stress in KrasG12D-expressing mutant cancer cells as indicated by a substantial increase in reactive oxidative species (ROS) production and depolarization of mitochondria. To examine the L-VC and D-VC toxicity effects, we administered high doses of D-VC and L-VC to CD1 mice and carried out an evaluation of their toxic effects. The daily injections of L-VC at a dose of 9.2 g/kg for 18 days were lethal to mice, while 80% of mice remained alive following the similar high-dose administration of D-VC. Following the drug injection courses and histopathological studies, we determined that a natural form of VC (L-VC) is more harmful and toxic to mice when compared to the effects caused by the similar doses of D-VC. Thus, our study indicates that the two enantiomers of VC have a similar potency in the induction of oxidative stress in cancer cells, but D-VC has a distinctive lower toxicity in mice compared to L-VC. While the mechanism of a distinctive toxicity between D-VC and L-VC is yet to be defined, our finding marks D-VC as a more preferable option compared to its natural enantiomer L-VC in clinical settings.

Exercise, cancer, and the cardiovascular system: clinical effects and mechanistic insights

Cardiovascular diseases and cancer are the leading causes of death in the Western world and share common risk factors. Reduced cardiorespiratory fitness (CRF) is a major determinant of cardiovascular morbidity and cancer survival. In this review we discuss cancer- induced disturbances of parenchymal, cellular, and mitochondrial function, which limit CRF and may be antagonized and attenuated through exercise training. We show the impact of CRF on cancer survival and its attenuating effects on cardiotoxicity of cancer-related treatment. Tailored exercise programs are not yet available for each tumor entity as several trials were performed in heterogeneous populations without adequate cardiopulmonary exercise testing (CPET) prior to exercise prescription and with a wide variation of exercise modalities. There is emerging evidence that exercise may be a crucial pillar in cancer treatment and a tool to mitigate cardiotoxic treatment effects. We discuss modalities of aerobic exercise and resistance training and their potential to improve CRF in cancer patients and provide an example of a periodization model for exercise training in cancer.

Molecular Mechanism of Natural Food Antioxidants to Regulate ROS in Treating Cancer: A Review

Cancer is the second-highest mortality rate disease worldwide, and it has been estimated that cancer will increase by up to 20 million cases yearly by 2030. There are various options of treatment for cancer, including surgery, radiotherapy, and chemotherapy. All of these options have damaging adverse effects that can reduce the patient's quality of life. Cancer itself arises from a series of mutations in normal cells that generate the ability to divide uncontrollably. This cell mutation can happen as a result of DNA damage induced by the high concentration of ROS in normal cells. High levels of reactive oxygen species (ROS) can cause oxidative stress, which can initiate cancer cell proliferation. On the other hand, the cytotoxic effect from elevated ROS levels can be utilized as anticancer therapy. Some bioactive compounds from natural foods such as fruit, vegetables, herbs, honey, and many more have been identified as a promising source of natural antioxidants that can prevent oxidative stress by regulating the level of ROS in the body. In this review, we have highlighted and discussed the benefits of various natural antioxidant compounds from natural foods that can regulate reactive oxygen species through various pathways.

Osteoclast Cancer Cell Metabolic Cross-talk Confers PARP Inhibitor Resistance in Bone Metastatic Breast Cancer

The majority of patients with late-stage breast cancer develop distal bone metastases. The bone microenvironment can affect response to therapy, and uncovering the underlying mechanisms could help identify improved strategies for treating bone metastatic breast cancer. Here, we observed that osteoclasts reduced the sensitivity of breast cancer cells to DNA damaging agents, including cisplatin and the PARP inhibitor (PARPi) olaparib. Metabolic profiling identified elevated glutamine production by osteoclasts. Glutamine supplementation enhanced the survival of breast cancer cells treated with DNA damaging agents, while blocking glutamine uptake increased sensitivity and suppressed bone metastasis. GPX4, the critical enzyme responsible for glutathione oxidation, was upregulated in cancer cells following PARPi treatment through stress-induced ATF4-dependent transcriptional programming. Increased glutamine uptake and GPX4 upregulation concertedly enhanced glutathione metabolism in cancer cells to help neutralize oxidative stress and generate PARPi resistance. Analysis of paired patient samples of primary breast tumors and bone metastases revealed significant induction of GPX4 in bone metastases. Combination therapy utilizing PARPi and zoledronate, which blocks osteoclast activity and thereby reduces the microenvironmental glutamine supply, generated a synergistic effect in reducing bone metastasis. These results identify a role for glutamine production by bone-resident cells in supporting metastatic cancer cells to overcome oxidative stress and develop resistance to DNA-damaging therapies.

SIGNIFICANCE

Metabolic interaction between osteoclasts and tumor cells contributes to resistance to DNA-damaging agents, which can be blocked by combination treatment with PARP and osteoclast inhibitors to reduce bone metastatic burden.

Deciphering the role of KRAS gene in oncogenesis: Focus on signaling pathways, genetic alterations in 3'UTR, KRAS specific miRNAs and therapeutic interventions

Cancer is a significant cause of death after cardiovascular disease. The genomic, epigenetic and environmental factors have been found to be the risk factor for the disease. The most important genes that develop cancer are oncogenes and tumor suppressor genes. Among oncogenes, KRAS has emerged as a significant player in the development of many cancers. Dysregulation of the RAS signaling pathway either on account of mutation in significant genes involved in the pathway or aberrant expression of different miRNAs targeting these genes including KRAS. The focus is also on the alterations in 3'UTR of the KRAS gene sequence as well as the changes in the miRNA encoding genes especially the one targeting the KRAS gene. Efforts are also being put in to target the dysregulated KRAS gene as a therapeutic approach to treat different cancers. However, there are some challenges like resistance to KRAS inhibitors that need to be addressed.

Cellulose nanocrystals-based fluorescent biocarrier binding GAPDH protein with high affinity in cancer-target doxorubicin delivery

Cellulose nanocrystals (CNCs) have shown immense promise in medical applications, especially in cancer treatment, owing to their excellent biocompatibility and potential for functional modifications. Considering the crucial role of the protein reduced glyceraldehyde-phosphate dehydrogenase (GAPDH) in cancer progression, we embarked to immobilize CNCs with GAPDH and fluorescent molecules FITC, creating FCNC-G through regioselective modifications. Furthermore, an accelerated proliferation of cancer cells was observed in the presence of FCNC-G. To evaluate the therapeutic potential of FCNC-G, we loaded it with doxorubicin (DOX) to create FCNC-G-D and tested its effect on Hepg2. We observed a significant inhibition of Hepg2 cells exposed to low concentrations of FCNC-G-D. Additionally, mitochondrial dysfunction was detected in Hepg2 and Cal27 cells, treated with FCNC-G-D, but not in A375 cells, further highlighting its selective impact on cancer cells. Given the limitations of DOX in clinical applications, our findings establish a strong foundation for further research on the potential of CNCs grafted with GAPDH as a novel cancer-targeted biocarrier with high affinity. The combination of CNCs unique properties with targeted delivery strategies holds tremendous promise for the development of more effective and safer cancer therapies.

High dose Vitamin C inhibits PD-L1 by ROS-pSTAT3 signal pathway and enhances T cell function in TNBC

Vitamin C (VitC) presents excellent anti-tumor effect for long time. Recently, high dose VitC achieved by intravenous administration manifests superior anti-tumor effect. However, the functions and detailed mechanisms of high dose VitC's role in cancer immunity are not fully understood. This study investigates the effect of high dose VitC on PD-L1 expression in triple negative breast cancer (TNBC) and the potential mechanism. Results showed VitC inhibited PD-L1 expression in breast cancer cell lines and enhanced anti-tumor effects of T cells. Furthermore, we found VitC inhibited PD-L1 transcription through ROS-pSTAT3 signal pathways. Consistent with in vitro results, in vivo study showed VitC suppressed tumor growth in immunocompetent mice and enhanced CD8+ T cells infiltration and function in tumor microenvironment. Our findings identify the effects of high dose VitC on PD-L1 expression and provide a rationale for the use of high dose VitC as immunomodulator for cancer therapy.

Regulation of antioxidants in cancer

Scientists in this field often joke, "If you don't have a mechanism, say it's ROS." Seemingly connected to every biological process ever described, reactive oxygen species (ROS) have numerous pleiotropic roles in physiology and disease. In some contexts, ROS act as secondary messengers, controlling a variety of signaling cascades. In other scenarios, they initiate damage to macromolecules. Finally, in their worst form, ROS are deadly to cells and surrounding tissues. A set of molecules with detoxifying abilities, termed antioxidants, is the direct counterpart to ROS. Notably, antioxidants exist in the public domain, touted as a "cure-all" for diseases. Research has disproved many of these claims and, in some cases, shown the opposite. Of all the diseases, cancer stands out in its paradoxical relationship with antioxidants. Although the field has made numerous strides in understanding the roles of antioxidants in cancer, many questions remain.

Vitamin C enhances the sensitivity of osteosarcoma to arsenic trioxide via inhibiting aerobic glycolysis

Osteosarcoma (OS) is a common malignant tumor disease in the department of orthopedics, which is prone to the age of adolescents and children under 20 years old. Arsenic trioxide (ATO), an ancient poison, has been reported to play a critical role in a variety of tumor treatments, including OS. However, due to certain poisonous side effects such as cardiotoxicity and hepatotoxicity, clinical application of ATO has been greatly limited. Here we report that low doses of ATO (1 μM) observably reduced the half-effective inhibitory concentration (IC50) of vitamin C on OS cells. Compared with the treatment alone, the synthetic application of vitamin C (VitC, 800 μM) and ATO (1 μM) significantly further inhibited the proliferation, migration, and invasion of OS cells and promoted cell apoptosis in vitro. Meanwhile, we observed that the combined application of VitC and ATO directly suppresses the aerobic glycolysis of OS cells with the decreased production of pyruvate, lactate, and ATP via inhibiting the expression of the critical glycolytic genes (PGK1, PGM1, and LDHA). Moreover, the combination of VitC (200 mg/kg) and ATO (1 mg/kg) with tail vein injection significantly delayed OS growth and migration of nude mice by inhibiting aerobic glycolysis of OS. Thus, our results demonstrate that VitC effectively increases the sensitivity of OS to low concentrations of ATO via inhibiting aerobic glycolysis to alleviate the toxic side effects of high doses of arsenic trioxide, suggesting that synthetic application of VitC and ATO is a promising approach for the clinical treatment of human OS.

Intracellular ascorbate is a safe-guard and/or reservoir for plasma vitamin C in prostate cancer patients undergoing radiotherapy

Prostate cancer (PC) represents one of the most common cancer types worldwide and many patients suffering from this kind of cancer are treated with radiotherapy (RTH). Ionizing irradiation is closely associated with reactive oxygen species (ROS) production and oxidative stress. Over the years the role of vitamin C (VC) in cancer prevention has been highlighted as it may be mediated by its ability to neutralize pro-carcinogenic ROS. However, the debate concerning the presence of VC in blood and its beneficial effect on the survival of cancer patients is inconsistent and controversial. To our best knowledge until recently there have been no studies concerning such a role of intracellular VC (iVC). In the present study, blood and intracellular concentrations of vitamin C were analyzed along with the level of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), as an established marker of the stress condition, in leukocytes of PC patients during the course of radiotherapy. The level of intracellular vitamin C significantly decreased in PC patients in comparison with the healthy group, while there were no differences in blood VC. It was observed that a sub-group of the PC patients reacted to RTH decreasing VC in leukocytes (group A), while the other sub-group acted the other way round, significantly increasing its level (group B). Under stressful conditions (RTH) leukocytes react in two different ways. Both ways are in good agreement with two well recognized functions, proposed for iVC; it may serve as a save factor, to protect the cellular DNA, increasing its concentration inside the cell (group B), and as a reservoir decreasing the VC level inside leukocytes and releasing VC into the plasma to rescue its physiological level (group A). It was also demonstrated that there was a relationship between the level of 8-oxodG in leukocytes' DNA and the markers of RTH toxicity.

Adaptive changes in tumor cells in response to reductive stress

Reductive stress is characterized by an excess of cellular electron donors and can be linked with various human pathologies including cancer. We developed melanoma cell lines resistant to reductive stress agents: rotenone (ROTR), n-acetyl-L-cysteine, (NACR), or dithiothreitol (DTTR). Resistant cells divided more rapidly and had intracellular homeostatic redox-couple ratios that were shifted towards the reduced state. Resistance caused alterations in general cell morphology, but only ROTR cells had significant changes in mitochondrial morphology with higher numbers that were more isolated, fragmented and swollen, with greater membrane depolarization and decreased numbers of networks. These changes were accompanied by lower basal oxygen consumption and maximal respiration rates. Whole cell flux analyses and mitochondrial function assays showed that NACR and DTTR preferentially utilized tricarboxylic acid (TCA) cycle intermediates, while ROTR used ketone body substrates such as D, L-β-hydroxybutyric acid. NACR and DTTR cells had constitutively decreased levels of reactive oxygen species (ROS), although this was accompanied by activation of nuclear factor erythroid 2-related factor 2 (Nrf2), with concomitant increased expression of the downstream gene products such as glutathione S-transferase P (GSTP). Further adaptations included enhanced expression of endoplasmic reticulum proteins controlling the unfolded protein response (UPR). Although expression patterns of these UPR proteins were distinct between the resistant cells, a trend implied that resistance to reductive stress is accompanied by a constitutively increased UPR phenotype in each line. Overall, tumor cells, although tolerant of oxidative stress, can adapt their energy and survival mechanisms in lethal reductive stress conditions.

Machine learning-based meta-analysis of colorectal cancer and inflammatory bowel disease

Colorectal cancer (CRC) is a major global health concern, resulting in numerous cancer-related deaths. CRC detection, treatment, and prevention can be improved by identifying genes and biomarkers. Despite extensive research, the underlying mechanisms of CRC remain elusive, and previously identified biomarkers have not yielded satisfactory insights. This shortfall may be attributed to the predominance of univariate analysis methods, which overlook potential combinations of variants and genes contributing to disease development. Here, we address this knowledge gap by presenting a novel multivariate machine-learning strategy to pinpoint genes associated with CRC. Additionally, we applied our analysis pipeline to Inflammatory Bowel Disease (IBD), as IBD patients face substantial CRC risk. The importance of the identified genes was substantiated by rigorous validation across numerous independent datasets. Several of the discovered genes have been previously linked to CRC, while others represent novel findings warranting further investigation. A Python implementation of our pipeline can be accessed publicly at https://github.com/AriaSar/CRCIBD-ML.

PARP inhibitor combinations with high-dose vitamin C in the treatment of Ewing sarcoma: two case reports and mechanistic overview

Ewing's sarcoma (ES) is a bone and soft tissue tumor that mainly occurs at a young age. The underlying cause of Ewing's sarcoma is the formation of fusion proteins between FET family genes and ETS family genes. Tumors with FET/ETS fusion genes can have defects in the DNA damage response and are sensitive to PARP inhibitors (PARPi). However, several studies have shown that PARPi alone is not sufficient to induce a meaningful antitumor response and that combinations of DNA-damaging agents with PARPi are required to achieve efficacy. Accordingly, preclinical studies have reported dramatic responses to PARPi treatment in combination with DNA-damaging agents such as temozolomide or irinotecan. Similarly, it has been previously reported that by generating reactive oxygen species, high-dose intravenous vitamin C (IVC) can induce DNA damage. This suggests that the combination of IVC with PARPi may increase genotoxic stress and enhance the antitumor response. In addition, unlike chemotherapeutic agents, IVC induces DNA damage selectively in cancer cells, and the side effects are significantly milder than those of chemotherapy. As ETS fusion-positive ES is deficient in faithful DNA repair, partly due to the interaction between ETS fusion products and PARP1, a PARPi plus IVC seems to be a logical and effective combination for the treatment of ETS fusion-positive ES. This paper reports significant responses to IVC (1-1.5 g/kg) in combination with PARPi (olaparib 300 mg BID or talazoparib 1 mg/day) in two patients with metastatic Ewing's sarcoma. The observations highlight an unmet therapeutic need for patients with advanced metastatic ES. The combination of PARPi with a selective DNA-damaging agent was effective in these cases. This case experience suggests that IVC may be incorporated into PARPi-based therapeutic strategies. Further studies are needed to confirm the efficacy of this combination in the treatment of Ewing sarcoma with ETS fusions.

GAPDH: unveiling its impact as a key hypoxia-related player in head and neck squamous cell carcinoma tumor progression, prognosis, and therapeutic potential

Head and neck squamous cell carcinoma (HNSCC), characterized by hypoxia patterns, ranks as the sixth most prevalent malignant tumor worldwide. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) plays a role in oncogenesis under hypoxic conditions in various cancers. However, its precise function in HNSCC, especially under varied hypoxic conditions, including at high altitudes, remains unclear. Elevated GAPDH mRNA and protein levels in HNSCC relative to normal tissues have been demonstrated through data from The Cancer Genome Atlas (TCGA), GSE29330, and the Human Protein Atlas (P<0.05). This elevation was further confirmed through in vitro experiments utilizing two HNSCC cell lines and a normal oral mucosal epithelial cell line. Additionally, data from TCGA and GSE41613 reveal a correlation between elevated GAPDH expression and diminished overall and progression-free survival in patients (P<0.05). Subsequent analysis identifies GAPDH as an independent risk factor for HNSCC (P<0.05). Using the ESTIMATE and single-sample gene set enrichment analysis (ssGSEA) algorithms, high GAPDH expression was found to be associated with reduced immune scores and diminished anti-tumor cell infiltration, such as CD8+ T cells, in TCGA and GSE41613 datasets (P<0.05). Analysis of single-cell RNA sequencing data from GSE139324 suggests that elevated GAPDH expression hinders communication between plasmacytoid dendritic cells and mast cells (P<0.05). Furthermore, in the TCGA and GSE41613 datasets, GAPDH's biological function is closely tied to hypoxia through Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Variation Analysis (GSVA) analyses. Moreover, its expression is linked to one cuproptosis-related gene, five N6-methyladenosine-related genes, six immune checkpoint genes, and pivotal pathways such as MYC and E2F (P<0.05). GAPDH showed excellent predictive value in estimating the efficacy of immunotherapy and 11 anti-tumor drugs (e.g., cisplatin) (P<0.05), using TIDE and pRRophetic algorithms on the TCGA and GSE41613 datasets. Under 1% O2 in vitro, HNSCC cells show elevated GAPDH expression, leading to decreased apoptosis and increased migration, clonogenicity, invasiveness, and resistance to cisplatin (P<0.05). At 5% O2, these effects persisted, albeit less pronouncedly. Inhibiting GAPDH reversed these effects under all oxygen concentrations (P<0.05). Overall, our findings reveal GAPDH as a key hypoxia-related player influencing tumor progression, prognosis, and therapeutic potential in HNSCC.

A Bioinspired Flexible Sensor for Electrochemical Probing of Dynamic Redox Disequilibrium in Cancer Cells

Malignant tumors pose a serious risk to human health. Ascorbic acid (AA) has potential for tumor therapy; however, the mechanism underlying the ability of AA to selectively kill tumor cells remains unclear. AA can cause redox disequilibrium in tumor cells, resulting in the release of abundant reactive oxygen species, represented by hydrogen peroxide (H2 O2 ). Therefore, the detection of H2 O2 changes can provide insight into the selective killing mechanism of AA against tumor cells. In this work, inspired by the ion-exchange mechanism in coral formation, a flexible H2 O2 sensor (PtNFs/CoPi@CC) is constructed to monitor the dynamics of H2 O2 in the cell microenvironment, which exhibits excellent sensitivity and spatiotemporal resolution. Moreover, the findings suggest that dehydroascorbic acid (DHA), the oxidation product of AA, is highly possible the substance that actually acts on tumor cells in AA therapy. Additionally, the intracellular redox disequilibrium and H2 O2 release caused by DHA are positively correlated with the abundance and activity of glucose transporter 1 (GLUT1). In conclusion, this work has revealed the potential mechanism underlying the ability of AA to selectively kill tumor cells through the construction and use of PtNFs/CoPi@CC. The findings provide new insights into the clinical application of AA.

Iron promotes glycolysis to drive colon tumorigenesis

Colorectal cancer (CRC) is the third most common cancer and is also the third leading cause of cancer-related death in the USA. Understanding the mechanisms of growth and progression of CRC is essential to improve treatment. Macronutrients such as glucose are energy source for a cell. Many tumor cells exhibit increased aerobic glycolysis. Increased tissue micronutrient iron levels in both mice and humans are also associated with increased colon tumorigenesis. However, if iron drives colon carcinogenesis via affecting glucose metabolism is still not clear. Here we found the intracellular glucose levels in tumor colonoids were significantly increased after iron treatment. 13C-labeled glucose flux analysis indicated that the levels of several labeled glycolytic products were significantly increased, whereas several tricarboxylic acid cycle intermediates were significantly decreased in colonoids after iron treatment. Mechanistic studies showed that iron upregulated the expression of glucose transporter 1 (GLUT1) and mediated an inhibition of the pyruvate dehydrogenase (PDH) complex function via directly binding with tankyrase and/or pyruvate dehydrogenase kinase (PDHK) 3. Pharmacological inhibition of GLUT1 or PDHK reactivated PDH complex function and reduced high iron diet-enhanced tumor formation. In conclusion, excess iron promotes glycolysis and colon tumor growth at least partly through the inhibition of the PDH complex function.

Potential therapies targeting nuclear metabolic regulation in cancer

The interplay between genetic alterations and metabolic dysregulation is increasingly recognized as a pivotal axis in cancer pathogenesis. Both elements are mutually reinforcing, thereby expediting the ontogeny and progression of malignant neoplasms. Intriguingly, recent findings have highlighted the translocation of metabolites and metabolic enzymes from the cytoplasm into the nuclear compartment, where they appear to be intimately associated with tumor cell proliferation. Despite these advancements, significant gaps persist in our understanding of their specific roles within the nuclear milieu, their modulatory effects on gene transcription and cellular proliferation, and the intricacies of their coordination with the genomic landscape. In this comprehensive review, we endeavor to elucidate the regulatory landscape of metabolic signaling within the nuclear domain, namely nuclear metabolic signaling involving metabolites and metabolic enzymes. We explore the roles and molecular mechanisms through which metabolic flux and enzymatic activity impact critical nuclear processes, including epigenetic modulation, DNA damage repair, and gene expression regulation. In conclusion, we underscore the paramount significance of nuclear metabolic signaling in cancer biology and enumerate potential therapeutic targets, associated pharmacological interventions, and implications for clinical applications. Importantly, these emergent findings not only augment our conceptual understanding of tumoral metabolism but also herald the potential for innovative therapeutic paradigms targeting the metabolism-genome transcriptional axis.

An ascorbic acid-decorated nanostructured surface on titanium inhibits breast cancer development and promotes osteogenesis

The chest wall is the most frequent metastatic site of breast cancer (BC) and the metastasis usually occurs in a solitary setting. Chest wall resection is a way to treat solitary BC metastasis, but intraoperative bone defects and local tumor recurrence still affect the life quality of patients. Titanium-based prostheses are widely used for chest wall repair and reconstruction, but their inherent bio-inertness makes their clinical performance unfavorable. Nanostructured surfaces can give titanium substrates the ability to excellently modulate a variety of cellular functions. Ascorbic acid is a potential stimulator of tumor suppression and osteogenic differentiation. An ascorbic acid-decorated nanostructured titanium surface was prepared through alkali treatment and spin-coating technique and its effects on the biological responses of BC cells and osteoblasts were assessed. The results exhibited that the nanorod structure and ascorbic acid synergistically inhibited the proliferation, spreading, and migration of BC cells. Additionally, the ascorbic acid-decorated nanostructured surface significantly promoted the proliferation and osteogenic differentiation of osteoblasts. This work may provide valuable references for the clinical application of titanium materials in chest wall reconstruction after the resection of metastatic BC.

Hypoxia-inducible factor 1α modulates interstitial pneumonia-mediated lung cancer progression

BACKGROUND

The prognosis of patients with lung cancer accompanied by interstitial pneumonia is poorer than that of patients with lung cancer but without interstitial pneumonia. Moreover, the available therapeutic interventions for lung cancer patients with interstitial pneumonia are limited. Therefore, a new treatment strategy for these patients is required. The aim of the present study was to investigate the pathophysiological relationship between interstitial pneumonia and lung cancer and explore potential therapeutic agents.

METHODS

A novel hybrid murine model of lung cancer with interstitial pneumonia was established via bleomycin-induced pulmonary fibrosis followed by orthotopic lung cancer cell transplantation into the lungs. Changes in tumor progression, lung fibrosis, RNA expression, cytokine levels, and tumor microenvironment in the lung cancer with interstitial pneumonia model were investigated, and therapeutic agents were examined. Additionally, clinical data and samples from patients with lung cancer accompanied by interstitial pneumonia were analyzed to explore the potential clinical significance of the findings.

RESULTS

In the lung cancer with interstitial pneumonia model, accelerated tumor growth was observed based on an altered tumor microenvironment. RNA sequencing analysis revealed upregulation of the hypoxia-inducible factor 1 signaling pathway. These findings were consistent with those obtained for human samples. Moreover, we explored whether ascorbic acid could be an alternative treatment for lung cancer with interstitial pneumonia to avoid the disadvantages of hypoxia-inducible factor 1 inhibitors. Ascorbic acid successfully downregulated the hypoxia-inducible factor 1 signaling pathway and inhibited tumor progression and lung fibrosis.

CONCLUSIONS

The hypoxia-inducible factor 1 pathway is critical in lung cancer with interstitial pneumonia and could be a therapeutic target for mitigating interstitial pneumonia-mediated lung cancer progression.

A tumor microenvironment-responsive microneedle patch for chemodynamic therapy of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumors of the head and neck, and this disease has become a threat to public health due to its poor prognosis and high fatality rate. Chemodynamic therapy (CDT) is an emerging oncology treatment based on the Fenton reaction. However, the lack of endogenous hydrogen peroxide (H2O2) in tumor cells and the high concentration of glutathione (GSH) that depletes toxic hydroxyl radicals (·OH) significantly impair the efficacy of CDT. Here, we developed a polyvinyl alcohol (PVA)-based soluble microneedle patch (denoted as Fe3O4 + VC-MN) loaded with Fe3O4 nanoparticles (NPs) and vitamin C (VC) for the effective treatment of OSCC. When Fe3O4 + VC-MNs are inserted into the OSCC tissue, the Fe3O4 NPs and VC loaded in the tip of the needle are released in a targeted manner. After VC is converted into oxidized vitamin C (DHA), it can consume GSH in tumor cells and generate sufficient intracellular H2O2in situ. Moreover, by virtue of their peroxidase-like activity, Fe3O4 NPs can induce the generation of lethal ·OH through the Fenton reaction with the aforementioned H2O2, leading to tumor cell ferroptosis and apoptosis, thus achieving CDT. Collectively, this functional microneedle patch provides a more efficient and minimally invasive targeted drug delivery solution for the treatment of OSCC.

Cellular Trafficking of Nanotechnology-Mediated mRNA Delivery

Messenger RNA (mRNA)-based therapy has emerged as a powerful, safe, and rapidly scalable therapeutic approach that involves technologies for both mRNA itself and the delivery vehicle. Although there are some unique challenges for different applications of mRNA therapy, a common challenge for all mRNA therapeutics is the transport of mRNA into the target cell cytoplasm for sufficient protein expression. This review is focused on the behaviors at the cellular level of nanotechnology-mediated mRNA delivery systems, which have not been comprehensively reviewed yet. First, the four main therapeutic applications of mRNA are introduced, including immunotherapy, protein replacement therapy, genome editing, and cellular reprogramming. Second, common types of mRNA cargos and mRNA delivery systems are summarized. Third, strategies to enhance mRNA delivery efficiency during the cellular trafficking process are highlighted, including accumulation to the cell, internalization into the cell, endosomal escape, release of mRNA from the nanocarrier, and translation of mRNA into protein. Finally, the challenges and opportunities for the development of nanotechnology-mediated mRNA delivery systems are presented. This review can provide new insights into the future fabrication of mRNA nanocarriers with desirable cellular trafficking performance.

Vitamin C intake and colorectal cancer survival according to KRAS and BRAF mutation: a prospective study in two US cohorts

BACKGROUND

The associations of vitamin C intake with colorectal cancer (CRC) survival according to tumour KRAS or BRAF mutation status remain unclear.

METHODS

We used the inverse probability weighted multivariable Cox proportional hazards regression model to calculate the hazard ratio (HR) of mortality, and spline analysis to evaluate the dose-response relationship in the Nurses' Health Study and Health Professionals Follow-up Study. We also assessed SLC2A1 mRNA expression according to KRAS or BRAF mutation in the TCGA database.

RESULTS

During an average of 12.0 years of follow-up, we documented 2,096 CRC cases, of which 703 cases had KRAS and BRAF mutation data. The association between total vitamin C intake and CRC-specific mortality suggestively differed according to KRAS or BRAF mutation status (Pinteraction = 0.04), with the multivariable HR (95% CI) per 400 mg/day increase in vitamin C intake for CRC-specific mortality of 1.07 (0.87-1.32, Ptrend = 0.52) in cases with both wild type and 0.74 (0.55-1.00, Ptrend < 0.05) in cases with either KRAS or BRAF mutant type. TCGA analysis showed a higher mRNA SLC2A1 expression in KRAS or BRAF-mutated tumours than in wild-type tumours (P = 0.02).

CONCLUSION

Our findings support the laboratory evidence for a potential benefit of vitamin C for CRC patients with KRAS or BRAF mutated tumours.

Co-Delivery of Metabolic Modulators Leads to Simultaneous Lactate Metabolism Inhibition and Intracellular Acidification for Synergistic Cancer Therapy

Simultaneous lactate metabolism inhibition and intracellular acidification (LIIA) is a promising approach for inducing tumor regression by depleting ATP. However, given the limited efficacy of individual metabolic modulators, a combination of various modulators is required for highly efficient LIIA. Herein, a co-delivery system that combines lactate transporter inhibitor, glucose oxidase, and O2 -evolving nanoparticles is proposed. As a vehicle, a facile room-temperature synthetic method for large-pore mesoporous silica nanoparticles (L-MSNs) is developed. O2 -evolving nanoparticles are then conjugated onto L-MSNs, followed by immobilizing the lactate transporter inhibitor and glucose oxidase inside the pores of L-MSNs. To load the lactate transporter inhibitor, which is too small to be directly loaded into the large pores, it is encapsulated in albumin by controlling the albumin conformation before being loaded into L-MSNs. Notably, inhibiting lactate efflux shifts the glucose consumption mechanism from lactate metabolism to glucose oxidase reaction, which eliminates glucose and produces acid. This leads to synergistic LIIA and subsequent ATP depletion in cancer cells. Consequently, L-MSN-based co-delivery of modulators for LIIA shows high anticancer efficacy in several mouse tumor models without toxicity in normal tissues. This study provides new insights into co-delivery of small-molecule drugs, proteins, and nanoparticles for synergistic metabolic modulation in tumors.

Identification of a small chemical as a lysosomal calcium mobilizer and characterization of its ability to inhibit autophagy and viral infection

We previously identified glyceraldehyde 3-phosphate dehydrogenase (GAPDH) as one of the cyclic adenosine diphosphoribose (cADPR)'s binding proteins and found that GAPDH participates in cADPR-mediated Ca2+ release from endoplasmic reticulum via ryanodine receptors (RyRs). Here, we aimed to chemically synthesise and pharmacologically characterise novel cADPR analogues. Based on the simulated cADPR-GAPDH complex structure, we performed the structure-based drug screening, identified several small chemicals with high docking scores to cADPR's binding pocket in GAPDH and showed that two of these compounds, C244 and C346, are potential cADPR antagonists. We further synthesised several analogues of C346 and found that its analogue, G42, also mobilised Ca2+ release from lysosomes. G42 alkalised lysosomal pH and inhibited autophagosome-lysosome fusion. Moreover, G42 markedly inhibited Zika virus (ZIKV, a flavivirus) or murine hepatitis virus (MHV, a β-coronavirus) infections of host cells. These results suggest that G42 inhibits virus infection, likely by triggering lysosomal Ca2+ mobilisation and inhibiting autophagy.

Recent advances and future directions in etiopathogenesis and mechanisms of reactive oxygen species in cancer treatment

A class of exceptionally bioactive molecules known as reactive oxygen species (ROS) have been widely studied in the context of cancer. They play a significant role in the etiopathogenesis for cancer. Implication of ROS in cancer biology is an evolving area, considering the recent advances; insights into their generation, role of genomic and epigenetic regulators for ROS, earlier thought to be a chemical process, with interrelations with cell death pathways- Apoptosis, ferroptosis, necroptosis and autophagy has been explored for newer targets that shift the balance of ROS towards cancer cell death. ROS are signal transducers that induce angiogenesis, invasion, cell migration, and proliferation at low to moderate concentrations and are considered normal by-products of a range of biological activities. Although ROS is known to exist in the oncology domain since time immemorial, its excessive quantities are known to damage organelles, membranes, lipids, proteins, and nucleic acids, resulting in cell death. In the last two decades, numerous studies have demonstrated immunotherapies and other anticancer treatments that modulate ROS levels have promising in vitro and in vivo effects. This review also explores recent targets for therapeutic interventions in cancer that are based on ROS generation or inhibition to disrupt the cell oxidative stress balance. Examples include-metabolic targets, targeted therapy with biomarkers, natural extracts and nutraceuticals and targets developed in the area of nano medicine. In this review, we present the molecular pathways which can be used to create therapy plans that target cancer by regulating ROS levels, particularly current developments and potential prospects for the effective implementation of ROS-mediated therapies in clinical settings. The recent advances in complex interaction with apoptosis especially ferroptosis and its role in epigenomics and modifications are a new paradigm, to just mechanical action of ROS, as highlighted in this review. Their inhibition by nutraceuticals and natural extracts has been a scientific challenging avenue that is explored. Also, the inhibition of generation of ROS by inhibitors, immune modulators and inhibitors of apoptosis and ferroptosis is explored in this review.

Multi-omic analysis reveals metabolic pathways that characterize right-sided colon cancer liver metastasis

There are well demonstrated differences in tumor cell metabolism between right sided (RCC) and left sided (LCC) colon cancer, which could underlie the robust differences observed in their clinical behavior, particularly in metastatic disease. As such, we utilized liquid chromatography-mass spectrometry to perform an untargeted metabolomics analysis comparing frozen liver metastasis (LM) biobank samples derived from patients with RCC (N = 32) and LCC (N = 58) to further elucidate the unique biology of each. We also performed an untargeted RNA-seq and subsequent network analysis on samples derived from an overlapping subset of patients (RCC: N = 10; LCC: N = 18). Our biobank redemonstrates the inferior survival of patients with RCC-derived LM (P = 0.04), a well-established finding. Our metabolomic results demonstrate increased reactive oxygen species associated metabolites and bile acids in RCC. Conversely, carnitines, indicators of fatty acid oxidation, are relatively increased in LCC. The transcriptomic analysis implicates increased MEK-ERK, PI3K-AKT and Transcription Growth Factor Beta signaling in RCC LM. Our multi-omic analysis reveals several key differences in cellular physiology which taken together may be relevant to clinical differences in tumor behavior between RCC and LCC liver metastasis.

Iron-Dependent Cell Death: A New Treatment Approach against Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating tumor type where a very high proportion of people diagnosed end up dying from cancer. Surgical resection is an option for only about 20% of patients, where the 5-year survival increase ranges from 10 to 25%. In addition to surgical resection, there are adjuvant chemotherapy schemes, such as FOLFIRINOX (a mix of Irinotecan, oxaliplatin, 5-Fluorouraci and leucovorin) or gemcitabine-based treatment. These last two drugs have been compared in the NAPOLI-3 clinical trial, and the NALIRIFOX arm was found to have a higher overall survival (OS) (11.1 months vs. 9.2 months). Despite these exciting improvements, PDAC still has no effective treatment. An interesting approach would be to drive ferroptosis in PDAC cells. A non-apoptotic reactive oxygen species (ROS)-dependent cell death, ferroptosis was first described by Dixon et al. in 2012. ROS are constantly produced in the tumor cell due to high cell metabolism, which is even higher when exposed to chemotherapy. Tumor cells have detoxifying mechanisms, such as Mn-SOD or the GSH-GPX system. However, when a threshold of ROS is exceeded in the tumor cell, the cell's antioxidant systems are overwhelmed, resulting in lipid peroxidation and, ultimately, ferroptosis. In this review, we point out ferroptosis as an approach to consider in PDAC and propose that altering the cellular ROS balance by combining oxidizing agents or with inhibitors of the main cellular detoxifiers triggers ferroptosis in PDAC.