Iron removal enhances vitamin C-induced apoptosis and growth inhibition of K-562 leukemic cells

Construction of iron metabolism-related prognostic features of gastric cancer based on RNA sequencing and TCGA database

BACKGROUND

Researches have manifested that the disorder of iron metabolism is participated in Gastric cancer (GC), but whether iron metabolism-relevant genes (IMRGs) is related to the survival outcome of GC remain unknown.

METHODS

Eleven tumor as well as nine adjacent normal tissues from GC patients were underwent mRNA sequencing, and the The Cancer Genome Atlas Stomach Cancer (TCGA-STAD) datasets were acquired from the TCGA database. Cox analyses and least absolute shrinkage and selection operator (LASSO) regression were applied to build a IMRGs signature. The relationship between signature genes and the infiltration profiling of 24 immune cells were investigated using single-sample GSEA (ssGSEA). Meanwhile, the potential biological significance, genes that act synergistically with signature genes, and the upstream regulatory targets were predicted. Finally, the abundance of the signature genes were measured via the quantitative real-time PCR (qRT-PCR).

RESULTS

A IMRGs signature was constructed according to the expression and corresponding coefficient of DOHH, P4HA3 and MMP1 (The Schoenfeld individual test showed risk score was not significant with P values = 0.83). The prognostic outcome of patients in the high-risk group was terrible (p < 0.05). Receiver operating characteristic (ROC) curves confirmed that the IMRGs signature presented good efficiency for predicting GC prognosis (AUC > 0.6). The nomogram was performed well for clinical utilize (C-index = 0.60), and the MMP1 expression significantly increased in the cohorts at age > 60 and Stage II-IV (p < 0.05). The positive correlation of P4HA3 and MMP1 expression as well as the negative correlation of DOHH expression with risk score (p < 0.0001) and worse prognosis (p < 0.05) were detected as well. Furthermore, 11 differential immune cells were associated with these signature genes (most p < 0.01). Finally, qRT-PCR revealed that the abundance of DOHH, P4HA3 and MMP1 were high in tumor cases, indicating the complex mechanism between the high expression of DOHH as a protective factor and the high expression of P4HA3 and MMP1 as the risk factors in the development of GC.

CONCLUSION

An iron metabolism-related signature was constructed and has significant values for foretelling the OS of GC.

Relevant Membrane Transport Proteins as Possible Gatekeepers for Effective Pharmacological Ascorbate Treatment in Cancer

Despite the increasing number of newly diagnosed malignancies worldwide, therapeutic options for some tumor diseases are unfortunately still limited. Interestingly, preclinical but also some clinical data suggest that the administration of pharmacological ascorbate seems to respond well, especially in some aggressively growing tumor entities. The membrane transport and channel proteins are highly relevant for the use of pharmacological ascorbate in cancer therapy and are involved in the transfer of active substances such as ascorbate, hydrogen peroxide, and iron that predominantly must enter malignant cells to induce antiproliferative effects and especially ferroptosis. In this review, the relevant conveying proteins from cellular surfaces are presented as an integral part of the efficacy of pharmacological ascorbate, considering the already known genetic and functional features in tumor tissues. Accordingly, candidates for diagnostic markers and therapeutic targets are mentioned.

Differences in the Pro/Antioxidative Status and Cellular Stress Response in Elderly Women after 6 Weeks of Exercise Training Supported by 1000 mg of Vitamin C Supplementation

Vitamin C supplementation and exercise influence pro/antioxidative status and the cellular stress response. We tested the effects of exercise training for 6 weeks, supported by 1000 mg of vitamin C supplementation in elderly women. Thirty-six women were divided into two groups: a control group (CON) (n = 18, age 69.4 ± 6.4 years, 70.4 ±10.4 kg body mass) and a supplemented group (SUPP) (n = 18, aged 67.7 ± 5.6 years, body mass 71.46 ± 5.39 kg). Blood samples were taken twice (at baseline and 24 h after the whole period of training), in order to determine vitamin C concentration, the total oxidative status/capacity (TOS/TOC), total antioxidant status/capacity (TAS/TAC), and gene expression associated with cellular stress response: encoding heat shock factor (HSF1), heat shock protein 70 (HSPA1A), heat shock protein 27 (HSPB1), and tumor necrosis factor alpha (TNF-α). We observed a significant increase in TOS/TOC, TAS/TAC, and prooxidant/antioxidant balance in the SUPP group. There was a significant decrease in HSPA1A in the CON group and a different tendency in the expression of HSF1 and TNF-α between groups. In conclusion, vitamin C supplementation enhanced the pro-oxidation in elderly women with a normal plasma vitamin C concentration and influenced minor changes in training adaptation gene expression.

Exogenous iron impairs the anti-cancer effect of ascorbic acid both in vitro and in vivo

INTRODUCTION

The anti-cancer effect of high concentrations of ascorbic acid (AA) has been well established while its underlying mechanisms remain unclear. The association between iron and AA has attracted great attention but was still controversial due to the complicated roles of iron in tumors.

OBJECTIVES

Our study aims to explore the anti-cancer mechanisms of AA and the interaction between AA and iron in cancer.

METHODS

The MTT and ATP assays were used to evaluate the cytotoxicity of AA. Reactive oxygen species (ROS) generation, calcium (Ca²⁺), and lipid peroxidation were monitored with flow cytometry. Mitochondrial dysfunction was assessed by mitochondrial membrane potential (MMP) detection with JC-1 or tetramethylrhodamine methyl ester (TMRM) staining. Mitochondrial swelling was monitored with MitoTracker Green probe. FeSO₄ (Fe²⁺), FeCl₃ (Fe³⁺), Ferric ammonium citrate (Fe³⁺), hemin chloride (Fe³⁺) were used as an iron donor to investigate the effects of iron on AA's anti-tumor activity. The in vivo effects of AA and iron were analyzed in xenograft zebrafish and allograft mouse models.

RESULTS

High concentrations of AA exhibited cytotoxicity in a panel of cancer cells. AA triggered ROS-dependent non-apoptotic cell death. AA-induced cell death was essentially mediated by the accumulated intracellular Ca²⁺, which was partly originated from endoplasmic reticulum (ER). Surprisingly, exogenous iron could significantly reverse AA-induced ROS generation, Ca²⁺ overloaded, and cell death. Especially, the iron supplements significantly impaired the in vivo anti-tumor activity of AA.

CONCLUSIONS

Our study elucidated the protective roles of iron in ROS/Ca²⁺ mediated necrosis triggered by AA both in vitro and in vivo, which might shed novel insight into the anti-cancer mechanisms and provide clinical application strategies for AA in cancer treatment.

Pterostilbene downregulates BCR/ABL and induces apoptosis of T315I-mutated BCR/ABL-positive leukemic cells

In this study, we examined the antileukemic effects of pterostilbene, a natural methylated polyphenol analog of resveratrol that is predominantly found in berries and nuts, using various human and murine leukemic cells, as well as bone marrow samples obtained from patients with leukemia. Pterostilbene administration significantly induced apoptosis of leukemic cells, but not of non-malignant hematopoietic stem/progenitor cells. Interestingly, pterostilbene was highly effective in inducing apoptosis of leukemic cells harboring the BCR/ABL fusion gene, including ABL tyrosine kinase inhibitor (TKI)-resistant cells with the T315I mutation. In BCR/ABL⁺ leukemic cells, pterostilbene decreased the BCR/ABL fusion protein levels and suppressed AKT and NF-κB activation. We further demonstrated that pterostilbene along with U0126, an inhibitor of the MEK/ERK signaling pathway, synergistically induced apoptosis of BCR/ABL⁺ cells. Our results further suggest that pterostilbene-promoted downregulation of BCR/ABL involves caspase activation triggered by proteasome inhibition-induced endoplasmic reticulum stress. Moreover, oral administration of pterostilbene significantly suppressed tumor growth in mice transplanted with BCR/ABL⁺ leukemic cells. Taken together, these results suggest that pterostilbene may hold potential for the treatment of BCR/ABL⁺ leukemia, in particular for those showing ABL-dependent TKI resistance.

Polymeric Iron Chelators Enhancing Pro-Oxidant Antitumor Efficacy of Vitamin C by Inhibiting the Extracellular Fenton Reaction

Intravenously injected high-dose vitamin C (VC) induces extracellular H₂O₂, which can penetrate into the tumor cells and suppress tumor growth. However, extracellular labile iron ions in the tumor decompose H₂O₂ via the Fenton reaction, limiting the therapeutic effect. In this regard, we recently developed a polymeric iron chelator that can inactivate the intratumoral labile iron ions. Here, we examined the effect of our polymeric iron chelator on the high-dose VC therapy in in vitro and in vivo. In the in vitro study, the polymeric iron chelator could inactivate the extracellular labile iron ions and prevent the unfavorable decomposition of VC-induced H₂O₂, augmenting pro-oxidative damage to DNA and inducing apoptosis in cultured cancer cells. Even in the in vivo study, the polymeric iron chelator significantly improved the antitumor effect of VC in subcutaneous DLD-1 and CT26 tumors in mice, while conventional iron chelators could not. This work indicates the importance of modulating tumor-associated iron ions in the high-dose VC therapy and should contribute to a better understanding of its mechanism.

Effect of six weeks 1000 mg/day vitamin C supplementation and healthy training in elderly women on genes expression associated with the immune response - a randomized controlled trial

Background

In this study, we investigated the effects of supplementation and exercise on the expression of genes associated with inflammation like CCL2, CRP, IL1, IL6, IL10 mRNA in elderly women.

Methods

Twenty four participants divided randomly into two groups were subjected to 6 weeks of the same health training program (three times per week). SUP group (supplemented, n = 12, mean age 72.8 ± 5.26 years and mean body mass 68.1 ± 8.3 kg) received 1000 mg of Vitamin C/day during the training period, while CON group (control, n = 12, mean age 72.4 ± 5.5 years and body mass 67.7 ± 7.5 kg) received placebo.

Results

No significant changes in IL-1, IL-6, IL-10 and CRP mRNA were observed within and between groups. However, there was a clear tendency of a decrease in IL-6 (two-way ANOVA, significant between investigated time points) and an increase in IL-10 mRNA noted in the supplemented group. A significant decrease in CCL2 mRNA was observed only in the CON group (from 2^0.2 to 2^0.1, p = 0.01).

Conclusions

It can be concluded, that 6 weeks of supplementation and exercise was too short to obtain significant changes in gene expression in leukocytes, but supplementation of 1000 mg vitamin C positively affected IL-6 and IL-10 expression – which are key changes in the adaptation to training. However, changes in body mass, IL1 and CCL2 were positive in CON group. It is possible that Vitamin C during 6 weeks of supplementation could have different effects on the expression of individual genes involved in the immune response.

Trial registration

Retrospectively registered. 

An Iron Metabolism-Related SLC22A17 for the Prognostic Value of Gastric Cancer

Purpose

Gastric cancer (GC) is a type of malignant cancer with a poor prognosis. The iron’s metabolism plays an important role in the process of GC. The aim of this study was to evaluate the effectiveness of SLC22A17, associated with iron metabolism, in predicting the prognosis of GC patients.

Materials and Methods

We analyzed genes related to iron metabolism of gastric cancer mRNA-seq data from TCGA database. We identified an iron metabolism-related SLC22A17 as an independent prognostic factor using univariate and multivariate Cox regression analysis.

Results

Further research showed that SLC22A17 was related with many pathways involved in the process of gastric cancer, and the expression was associated with diverse cancer-infiltrating immune cells. The expression of SLC22A17 was associated with T (Topography).

Conclusion

We validated that SLC22A17 associated with iron metabolism could serve as a prognostic biomarker for GC patients.

Exercise Training and Vitamin C Supplementation Affects Ferritin mRNA in Leukocytes without Affecting Prooxidative/Antioxidative Balance in Elderly Women

Physical training and antioxidant supplementation may influence iron metabolism through reduced oxidative stress and subsequent lowering of mRNA levels of genes that are easily induced by this stress, including those responsible for iron homeostasis. Fifteen elderly women participated in our 12-week experiment, involving six weeks of training without supplementation and six weeks of training supported by oral supplementation of 1000 mg of vitamin C daily. The participants were divided into two groups (n = 7 in group 1 and n = 8 in group 2). In group 1, we applied vitamin C supplementation in the first six weeks of training, while in group 2 during the remaining six weeks of training. In both phases, the health-related training occurred three times per week. Training accompanied by vitamin C supplementation did not affect prooxidative/antioxidative balance but significantly decreased ferritin heavy chain (FTH) and ferritin light chain (FTL) mRNA in leukocytes (for FTH mRNA from 2^64.24 to 2^11.06, p = 0.03 in group 1 and from 2^60.54 to 2^16.03, p = 0.01 in group 2, for FTL mRNA from 2^20.22 to 2^4.53, p = 0.01 in group 2). We concluded that vitamin C supplementation might have caused a decrease in gene expression of two important antioxidative genes (FTH, FTL) and had no effect on plasma prooxidative/antioxidative balance.

Pro- and Antioxidant Effects of Vitamin C in Cancer in correspondence to Its Dietary and Pharmacological Concentrations

Vitamin C is an antioxidant that may scavenge reactive oxygen species preventing DNA damage and other effects important in cancer transformation. Dietary vitamin C from natural sources is taken with other compounds affecting its bioavailability and biological effects. High pharmacological doses of vitamin C may induce prooxidant effects, detrimental for cancer cells. An oxidized form of vitamin C, dehydroascorbate, is transported through glucose transporters, and cancer cells switch from oxidative phosphorylation to glycolysis in energy production so an excess of vitamin C may limit glucose transport and ATP production resulting in energetic crisis and cell death. Vitamin C may change the metabolomic and epigenetic profiles of cancer cells, and activation of ten-eleven translocation (TET) proteins and downregulation of pluripotency factors by the vitamin may eradicate cancer stem cells. Metastasis, the main reason of cancer-related deaths, requires breakage of anatomical barriers containing collagen, whose synthesis is promoted by vitamin C. Vitamin C induces degradation of hypoxia-inducible factor, HIF-1, essential for the survival of tumor cells in hypoxic conditions. Dietary vitamin C may stimulate the immune system through activation of NK and T cells and monocytes. Pharmacological doses of vitamin C may inhibit cancer transformation in several pathways, but further studies are needed to address both mechanistic and clinical aspects of this effect.

Fenton Reaction-Assisted Photodynamic Therapy for Cancer with Multifunctional Magnetic Nanoparticles

Tumor hypoxia and the short half-life of reactive oxygen species (ROS) with small diffusion distance have greatly limited the therapeutic effect of photodynamic therapy (PDT). Here, a multifunctional nanoplatform is developed to enhance the PDT effect through increasing the oxygen concentration in tumor cells by the Fenton reaction and reducing the distance between the ROS and the target site by mitochondrial targeting. Fe₃O₄@Dex-TPP nanoparticles are first prepared by coprecipitation in the presence of triphenylphosphine (TPP)-grafted dextran (Dex-TPP) and Fe²⁺/Fe³⁺, which have a magnetic resonance imaging effect. Next, the photosensitizers of protoporphyrin IX (PpIX) and glutathione-responsive mPEG-ss-COOH are grafted on Fe₃O₄@Dex-TPP to form Fe₃O₄@Dex/TPP/PpIX/ss-mPEG nanoparticles. After the nanoparticles are internalized, part of Fe₃O₄ are decomposed into Fe²⁺/Fe³⁺ in the acidic lysosome and then Fe²⁺/Fe³⁺ diffused into the cytoplasm, and subsequently, Fe²⁺ reacted with the overproduced H₂O₂ to produce O₂ and ^•OH. The undecomposed nanoparticles enter the cytoplasm by photoinduced internalization and targeted to the mitochondria, leading to ROS direct generation around the mitochondria. Simultaneously, the produced O₂ by the Fenton reaction can serve as a raw material for PDT to continuously exert PDT effect. As a result, the Fenton reaction-assisted PDT can significantly improve the therapeutic efficacy of tumors.

Anticancer activity of a novel methylated analogue of L-mimosine against an in vitro model of human malignant melanoma

The anticancer activity of a series of novel synthesized, hydroxypyridone-based metal chelators (analogues of L-mimosine) was evaluated in an in vitro model of melanoma consisting of malignant melanoma (A375), non-melanoma epidermoid carcinoma (A431) and immortalized non-malignant keratinocyte (HaCaT) cells. More specifically, we have demonstrated that the L-enantiomer of a methylated analogue of L-mimosine (compound 22) can exert a potent anticancer effect in A375 cells when compared to either A431 or HaCaT cells. Moreover, we have demonstrated that this analogue has the ability to i) promote increased generation of reactive oxygen species (ROS), ii) activate both intrinsic and extrinsic apoptosis and iii) induce perturbations in cell cycle growth arrest. Our data highlights the potential of compound 22 to act as a promising therapeutic agent against an in vitro model of human malignant melanoma.