Should Patients Undergoing Chemotherapy and Radiotherapy Be Prescribed Antioxidants?

Oral Complications and Management Strategies for Cancer Patients: Principles of Supportive Oncology in Dentistry

PURPOSE OF REVIEW

It is recognized that patients undergoing cancer treatment experience different adverse effects depending on the type of therapy they received. The objective of this work is to provide a scientific evidence-based protocol for oral care in cancer patients. Cancer resection surgery, chemotherapy, and radiotherapy can cause important complications that impact patients' quality of life.

RECENT FINDINGS

Cancer patients, from the moment of diagnosis to the end of treatment and subsequent follow-up, have diverse care needs, both from a systemic and local point of view. The implementation of oral care protocols before, during, and after cancer therapy is essential because it helps to identify risk factors for the development of predictable oral complications. It is essential to establish that all cancer patients, before starting treatment, undergo a systematic dental check-up to avoid limitations during treatment and also alter their quality of life. Regular professional oral care maintenance and follow-up programs are essential to maintaining a patient's long-term oral health.

Vitamin C: historical perspectives and heart failure

Vitamin C (Vit C) is an ideal antioxidant as it is easily available, water soluble, very potent, least toxic, regenerates other antioxidants particularly Vit E, and acts as a cofactor for different enzymes. It has received much attention due to its ability in limiting reactive oxygen species, oxidative stress, and nitrosative stress, as well as it helps to maintain some of the normal metabolic functions of the cell. However, over 140 clinical trials using Vit C in different pathological conditions such as myocardial infarction, gastritis, diabetes, hypertension, stroke, and cancer have yielded inconsistent results. Such a divergence calls for new strategies to establish practical significance of Vit C in heart failure or even in its prevention. For a better understanding of Vit C functioning, it is important to revisit its transport across the cell membrane and subcellular interactions. In this review, we have highlighted some historical details of Vit C and its transporters in the heart with a particular focus on heart failure in cancer chemotherapy.

Radiation Induced Metabolic Alterations Associate With Tumor Aggressiveness and Poor Outcome in Glioblastoma

Glioblastoma (GBM) is uniformly fatal with a 1-year median survival, despite best available treatment, including radiotherapy (RT). Impacts of prior RT on tumor recurrence are poorly understood but may increase tumor aggressiveness. Metabolic changes have been investigated in radiation-induced brain injury; however, the tumor-promoting effect following prior radiation is lacking. Since RT is vital to GBM management, we quantified tumor-promoting effects of prior RT on patient-derived intracranial GBM xenografts and characterized metabolic alterations associated with the protumorigenic microenvironment. Human xenografts (GBM143) were implanted into nude mice 24 hrs following 20 Gy cranial radiation vs. sham animals. Tumors in pre-radiated mice were more proliferative and more infiltrative, yielding faster mortality (p < 0.0001). Histologic evaluation of tumor associated macrophage/microglia (TAMs) revealed cells with a more fully activated ameboid morphology in pre-radiated animals. Microdialyzates from radiated brain at the margin of tumor infiltration contralateral to the site of implantation were analyzed by unsupervised liquid chromatography-mass spectrometry (LC-MS). In pre-radiated animals, metabolites known to be associated with tumor progression (i.e., modified nucleotides and polyols) were identified. Whole-tissue metabolomic analysis of pre-radiated brain microenvironment for metabolic alterations in a separate cohort of nude mice using ¹H-NMR revealed a significant decrease in levels of antioxidants (glutathione (GSH) and ascorbate (ASC)), NAD⁺, Tricarboxylic acid cycle (TCA) intermediates, and rise in energy carriers (ATP, GTP). GSH and ASC showed highest Variable Importance on Projection prediction (VIPpred) (1.65) in Orthogonal Partial least square Discriminant Analysis (OPLS-DA); Ascorbate catabolism was identified by GC-MS. To assess longevity of radiation effects, we compared survival with implantation occurring 2 months vs. 24 hrs following radiation, finding worse survival in animals implanted at 2 months. These radiation-induced alterations are consistent with a chronic disease-like microenvironment characterized by reduced levels of antioxidants and NAD⁺, and elevated extracellular ATP and GTP serving as chemoattractants, promoting cell motility and vesicular secretion with decreased levels of GSH and ASC exacerbating oxidative stress. Taken together, these data suggest IR induces tumor-permissive changes in the microenvironment with metabolomic alterations that may facilitate tumor aggressiveness with important implications for recurrent glioblastoma. Harnessing these metabolomic insights may provide opportunities to attenuate RT-associated aggressiveness of recurrent GBM.

FGF Trapping Inhibits Multiple Myeloma Growth through c-Myc Degradation-Induced Mitochondrial Oxidative Stress

Multiple myeloma, the second most common hematologic malignancy, frequently relapses because of chemotherapeutic resistance. Fibroblast growth factors (FGF) act as proangiogenic and mitogenic cytokines in multiple myeloma. Here, we demonstrate that the autocrine FGF/FGFR axis is essential for multiple myeloma cell survival and progression by protecting multiple myeloma cells from oxidative stress-induced apoptosis. In keeping with the hypothesis that the intracellular redox status can be a target for cancer therapy, FGF/FGFR blockade by FGF trapping or tyrosine kinase inhibitor impaired the growth and dissemination of multiple myeloma cells by inducing mitochondrial oxidative stress, DNA damage, and apoptotic cell death that were prevented by the antioxidant vitamin E or mitochondrial catalase overexpression. In addition, mitochondrial oxidative stress occurred as a consequence of proteasomal degradation of the c-Myc oncoprotein that led to glutathione depletion. Accordingly, expression of a proteasome-nondegradable c-Myc protein mutant was sufficient to avoid glutathione depletion and rescue the proapoptotic effects due to FGF blockade. These findings were confirmed on bortezomib-resistant multiple myeloma cells as well as on bone marrow-derived primary multiple myeloma cells from newly diagnosed and relapsed/refractory patients, including plasma cells bearing the t(4;14) translocation obtained from patients with high-risk multiple myeloma. Altogether, these findings dissect the mechanism by which the FGF/FGFR system plays a nonredundant role in multiple myeloma cell survival and disease progression, and indicate that FGF targeting may represent a therapeutic approach for patients with multiple myeloma with poor prognosis and advanced disease stage. SIGNIFICANCE: This study provides new insights into the mechanisms by which FGF antagonists promote multiple myeloma cell death. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/11/2340/F1.large.jpg.

Novel tetrahydroacridine derivatives with iodobenzoic moieties induce G0/G1 cell cycle arrest and apoptosis in A549 non-small lung cancer and HT-29 colorectal cancer cells

A series of nine tetrahydroacridine derivatives with iodobenzoic moiety were synthesized and evaluated for their cytotoxic activity against cancer cell lines—A549 (human lung adenocarcinoma), HT-29 (human colorectal adenocarcinoma) and somatic cell line—EA.hy926 (human umbilical vein cell line). All compounds displayed high cytotoxicity activity against A549 (IC₅₀ 59.12–14.87 µM) and HT-29 (IC₅₀ 17.32–5.90 µM) cell lines, higher than control agents—etoposide and 5-fluorouracil. Structure–activity relationship showed that the position of iodine in the substituent in the para position and longer linker most strongly enhanced the cytotoxic effect. Among derivatives, 1i turned out to be the most cytotoxic and displayed IC₅₀ values of 14.87 µM against A549 and 5.90 µM against HT-29 cell lines. In hyaluronidase inhibition assay, all compounds presented anti-inflammatory activity, however, slightly lower than reference compound. ADMET prediction showed that almost all compounds had good pharmacokinetic profiles. 1b, 1c and 1f compounds turned out to act against chemoresistance in cisplatin-resistant 253J B-V cells. Compounds intercalated into DNA and inhibited cell cycle in G0/G1 phase—the strongest inhibition was observed for 1i in A549 and 1c in HT-29. Among compounds, the highest apoptotic effect in both cell lines was observed after treatment with 1i. Compounds caused DNA damage and H2AX phosphorylation, which was detected in A549 and HT-29 cells. All research confirmed anticancer properties of novel tetrahydroacridine derivatives and explained a few pathways of their mechanism of cytotoxic action.

Retinol palmitate and ascorbic acid: Role in oncological prevention and therapy

Cancer development has been directly related to oxidative stress. During chemotherapy, some cancer patients use dietary antioxidants to avoid nutritional deficiencies due to cancer treatment. Among the antioxidants consumed, there are vitamins, including retinyl palmitate (PR) and ascorbic acid (AA), which have the capacity to reduce free radicals formation, protect cellular structures and maintain the cellular homeostasis. This systematic review evaluated the antioxidant and antitumor mechanisms of retinol palmitate (a derivative of vitamin A) and/or ascorbic acid (vitamin C) in cancer-related studies. Ninety-seven (97) indexed articles in the databases PubMed and Science Direct, published between 2013 and 2017, including 23 clinical studies (5 for every single compound while 13 in interaction) and 74 non-clinical studies (37 for retinol palmitate, 36 for ascorbic acid and 1 in interaction) were considered. Antioxidant and antitumor effects, with controversies over dosage and route of administration, were observed for the test compounds in their isolated form or associated in clinical studies. Prevention of cancer risks against oxidative damage was seen in lower doses of retinol palmitate and/or vitamin C. However, at high doses, they can generate reactive oxygen species, cytotoxicity and apoptosis in test systems. Non-clinical studies using cell lines have allowed understanding the mechanisms related to antioxidants and antitumor effects of the isolated compounds, however, studies on vitamin interactions, acting as antioxidants and/or antitumor are still rare and controversial. More studies, mainly related to modulation of antineoplastic drugs are needed for understanding the risks and benefits of their use during treatment in order to achieve effectiveness in cancer therapy and patient's quality of life.

Effect of ursodeoxycholic acid and vitamin E in the prevention of liver injury from methotrexate in pediatric leukemia

BACKGROUND/AIMS

Ursodeoxycholic acid (UDCA) and antioxidants such as vitamin E are considered to have a protective role in preventing chemotherapy-induced liver damage. The aim of this study was to assess the efficacy of these agents for hepatoprotection in pediatric patients with B-cell acute lymphoblastic leukemia (ALL), who were treated with methotrexate in their maintenance phase of treatment.

MATERIALS AND METHODS

Eighty children with B-cell ALL were randomly divided into four groups. Group 1 was administered oral vitamin E (400 mg/day); group 2 was administered oral UDCA (15 mg/kg/day); group 3 was administered a combination of the two drugs; and group 4 served as a control group and was administered no drug except their chemotherapy drugs. Complete blood count, liver function test, liver ultrasonography, and liver fibroscan were requested, and the results were compared.

RESULTS

Group 1 showed a slight increase in total bilirubin levels compared to baseline levels during the study (P=0.036). Group 2 showed a decline in aspartate aminotransferase and alanine aminotransferase levels during the study and at 6 months after discontinuing the drug; however, these differences were not statistically significant (P=0.051 and 0.083, respectively). None of the patients showed the evidence of significant fibrosis on liver fibroscan. Eight patients showed some evidence of mild-to-moderate fibrosis (F1, F2), but the results were not different between the groups as well as between pre- and post-study periods in each group.

CONCLUSION

Low-dose methotrexate does not cause significant liver fibrosis in pediatric leukemia. UDCA and vitamin E have minimal roles in hepatoprotection among pediatric patients with ALL.

Low-dose doxorubicin with carotenoids selectively alters redox status and upregulates oxidative stress-mediated apoptosis in breast cancer cells

The combination of carotenoids and doxorubicin (DOX) selectively alters oxidative stress-mediated apoptosis in breast cancer cells. Primarily, cytotoxic efficiency of carotenoids (β-carotene, BC; lutein, LUT; astaxanthin, AST; or fucoxanthin, FUCO) either with or without a minimal cytotoxic dose of DOX was evaluated in MCF-7 (0.12 μM) and MDA-MB-231 cells (0.28 μM). The higher cell growth inhibition of BC and/or LUT with DOX was selected for testing in further cell-based assays. Low-dose DOX significantly enhanced cytotoxicity in carotenoid (<5 μM)-treated cells compared to high-dose DOX (>1 μM) or carotenoid (20 μM) treatment alone. Depleted glutathione, increased lipid peroxides and increased ROS levels in cells confirmed the cytotoxic effect. Furthermore, mitochondrial dysfunction, cell growth arrest at G0/G1 phase and caspase cascades as well as up- and down-regulated expression levels of related proteins (p21, p27, Bax, p53, Bcl-2, and cyclin D1) revealed the synergistic effect of carotenoid and DOX treatment on ROS-mediated apoptosis. These observations demonstrated increased apoptosis in BC + DOX/LUT + DOX-treated cells due to the pronounced pro-oxidant action. Interestingly, normal breast epithelial cells (MCF 10A) exposed to similar treatments resulted in non-significant cytotoxicity. These newly observed mechanistic differences of anticancer drugs on the mitigation of toxicity with carotenoids may provide insight into the targeting of cancer therapy.

Cardioprotective mechanisms of phytochemicals against doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is an anthracycline antibiotic, which is effectively used in the treatment of different malignancies, such as leukemias and lymphomas. Its most serious side effect is dose-dependent cardiotoxicity, which occurs through inducing oxidative stress apoptosis. Due to the myelosuppressive effect of dexrazoxane, a commonly-used drug to alleviate DOX-induced cardiotoxicity, researchers investigated the potential of phytochemicals for prophylaxis and treatment of this condition. Phytochemicals are plant chemicals that have protective or disease preventive properties. Preclinical trials have shown antioxidant properties for several plant extracts, such as those of Aerva lanata, Aronia melanocarpa, Astragalus polysaccharide, and Bombyx mori plants. Other plant extracts showed an ability to inhibit apoptosis, such as those of Astragalus polysaccharide, Azadirachta indica, Bombyx mori, and Allium stavium plants. Unlike synthetic agents, phytochemicals do not impair the clinical activity of DOX and they are particularly safe for long-term use. In this review, we summarized the results of preclinical trials that investigated the cardioprotective effects of phytochemicals against DOX-induced cardiotoxicity. Future human trials are required to translate these cardioprotective mechanisms into practical clinical implications.

Protective Role of Silymarin on Hepatic and Renal Toxicity Induced by MTX Based Chemotherapy in Children with Acute Lymphoblastic Leukemia

BACKGROUND

ALL is the most common childhood malignancy. The children with ALL are treated with methotrexate (MTX) based chemotherapy protocols. MTX causes unpredictable serious hepatic and renal side effects. Silymarin has antioxidant and anti-inflammatory activities and stimulates tissue regeneration. This study aims to evaluate the protective effects of Silymarin on MTX-based chemotherapy-induced Hepatic and renal toxicity in children with ALL.

PATIENTS AND METHODS

80 children with newly diagnosed ALL were enrolled in the study. They were randomly divided into two groups. Group I included 40 children with ages ranging from 4-13 years and the mean age of 6.85± 2.89 years, who received Silymarin 420 mg/day in 3 divided doses for one week after each MTX dose. Group II included 40 children, with ages ranging from 4-12 years and the mean age of 7.30±2.6 years, who received placebo for one week after MTX therapy. For all patients liver functions including serum bilirubin, total proteins, albumin, globulin and albumin-globulin ratio, alkaline phosphatase, ALT and AST, prothrombin time and activity and renal functions including blood urea and serum creatinine, serum cystatin C and urinary N-acetyl-beta-D-glucosaminidase were done to assess hepatic and renal toxicity before and after chemotherapy.

RESULTS

There were no significant differences between group I and II as regard liver and renal functions before chemotherapy. After chemotherapy, there were significantly higher values of ALT and AST and alkaline phosphatase, and significantly lower Prothrombin activity in group II compared with group I. No significant differences between group I and II were found in total bilirubin, serum protein, and albumin levels. There was significantly lower blood urea, serum creatinine, and cystatin C and urinary N-acetyl-beta-D-glucosaminidase in group I compared with group II.

CONCLUSION

Silymarin improved some hepatic and renal functions in children with ALL who received MTX-based chemotherapy protocols.

RECOMMENDATIONS

Extensive multicenter studies could be recommended to prove the hepatic and renal protective effects of Silymarin in patients with ALL who received MTX-based chemotherapy protocols.

The Use of Complementary and Alternative Medicine Supplements of Potential Concern during Breast Cancer Chemotherapy

Objective. While many Complementary and Alternative Medicines (CAM) are unlikely to interact negatively with conventional oncology treatment, some ingestible CAM substances have biological activities that may reduce the effectiveness of chemotherapy or radiation. This study surveyed women with breast cancer in order to document the extent to which women with breast cancer use these CAM substances of concern concurrently with conventional treatments. Methods. A total of 398 women completed a survey describing their use of CAM at various time points in their cancer treatment. This report focuses on a subsample of 250 women receiving chemotherapy or radiation who reported using specific one or more of several chemotherapies. Results. Of those participating, 104 (43.7%) of those receiving chemotherapy (n = 238) and 45 (32.3%) of those receiving radiation (139; 58.4% of all patients) reported using one or more CAM substances that could be cause for concern when taken concurrently. Conclusion. Research is needed to understand the real risks associated with CAM and conventional polypharmacy. If risks associated with CAM conventional polypharmacy use prove to be substantial then improved systems to assure all women get advice regarding herb and supplement use during breast cancer treatment appear to be needed.

Micronutrients in Oncological Intervention

Nutritional supplements are widely used among patients with cancer who perceive them to be anticancer and antitoxicity agents. Depending on the type of malignancy and the gender 30%-90% of the cancer patients supplement their diets with antioxidant and immuno-stabilizing micronutrients, such as selenium, vitamin C, and vitamin D, often without the knowledge of the treating physician. From the oncological viewpoint, there are justifiable concerns that dietary supplements decrease the effectiveness of chemotherapy and radiotherapy. Recent studies, however, have provided increasing evidence that treatment is tolerated better-with an increase in patient compliance and a lower rate of treatment discontinuations-when micronutrients, such as selenium, are added as appropriate to the patient's medication. Nutritional supplementation tailored to an individual's background diet, genetics, tumor histology, and treatments may yield benefits in subsets of patients. Clinicians should have an open dialogue with patients about nutritional supplements. Supplement advice needs to be individualized and come from a credible source, and it is best communicated by the physician.

Vitamin E neuroprotection against cisplatin ototoxicity: Preliminary results from a randomized, placebo-controlled trial

BACKGROUND

Few studies have investigated the effect of vitamin E in reducing the cisplatin (CDDP)-induced ototoxicity. This study evaluated vitamin E supplementation as a protecting agent against CDDP-induced ototoxicity.

METHODS

Patients who started CDDP were randomly assigned to receive vitamin E supplementation at 400 mg per day (group 1) or placebo (group 2). Audiograms and evoked brainstem responses were obtained at baseline, and after 1, 2, and 3 months.

RESULTS

Twenty-three patients affected by solid malignancies were enrolled (13 in group 1 and 10 in group 2). At 1 month, a significant hearing loss in group 2 at both 2000 HZ (right ear: p = .05; left ear: p = .04) and 8000 HZ (right ear: p = .04; left ear: p = .03) was detected when compared to baseline values. Audiograms did not show significant changes. At 1 month, evoked brainstem responses remained unchanged in both arms without significant differences between groups.

CONCLUSION

These preliminary findings confirm the neuroprotective properties of vitamin E against the CDDP-induced ototoxicity. © 2016 Wiley Periodicals, Inc. Head Neck 38: E2118-E2121, 2016.

Survey of Policies and Guidelines on Antioxidant Use for Cancer Prevention, Treatment, and Survivorship in North American Cancer Centers: What Do Institutions Perceive as Evidence?

BACKGROUND

Health care policies and guidelines that are clear and consistent with research evidence are important for maximizing clinical outcomes. To determine whether cancer centers in Canada and the United States had policies and/or guidelines about antioxidant use, and whether policies were aligned with the evidence base, we reviewed current research evidence in the field, and we undertook a survey of the policies and guidelines on antioxidant use at cancer institutions across North America.

METHODS

A survey of policies and guidelines on antioxidant use and the development and communication of the policies and guidelines was conducted by contacting cancer institutions in North America. We also conducted a Website search for each institution to explore any online resources.

RESULTS

Policies and guidelines on antioxidant use were collected from 78 cancer institutions. Few cancer institutions had policies (5%) but most provided guidelines (69%). Antioxidants from diet were generally encouraged at cancer institutions, consistent with the current research evidence. In contrast, specific antioxidant supplements were generally not recommended at cancer institutions. Policies and guidelines were developed using evidence-based methods (53%), by consulting another source (35%), or through discussions/conference (26%), and communicated mainly through online resources (65%) or written handouts (42%). For cancer institutions that had no policy or guideline on antioxidants, lack of information and lack of time were the most frequently cited reasons.

CONCLUSIONS

Policies and guidelines on antioxidants from diet were largely consistent with the research evidence. Policies and guidelines on antioxidant supplements during treatment were generally more restrictive than the research evidence might suggest, perhaps due to the specificity of results and the inability to generalize findings across antioxidants, adding to the complexity of their optimal and safe use. Improved communication of comprehensive research evidence to cancer institutions may aid in the development of more evidence-based policies and guidelines.

Reduction of oxidative stress in liver cancer patients by oral green tea polyphenol tablets during hepatic arterial infusion chemotherapy

Hepatic arterial infusion chemotherapy (HAI) using an implanted port system is the standard regimen for primary and metastatic liver cancers (MLCs). However, there have been few studies concerning HAI-induced oxidative stress and damage to the liver or other organs. The aim of the present study was to investigate the ability of green tea polyphenols (GTPs) to reduce the oxidative stress or increase the biological antioxidative potential in HAI-treated patients. A total of 19 patients with inoperable hepatocellular carcinoma (HCC) or MLC from colorectal malignancy were eligible for HAI with cisplatin (CDDP) and 5-fluorouracil (5FU). The study subjects were randomly assigned to either a 3 or a 6 oral GTP tablets per day group. Each tablet had a GTP content equivalent to 79 mg of epigallocatechin-3-gallate. The oxidative stress was assessed by measuring the levels of derivatives of reactive oxygen metabolites (d-ROMs) and the biological antioxidative potential (BAP) values in patient plasma using the Free Radical Analytical System 4 (FRAS4), and correlating the results with clinical laboratory data for the patients. The levels of d-ROMs were significantly reduced by the oral intake of 6 GTP tablets for 6–9 months (P=0.0463) but were not significantly reduced by the oral intake of 3 GTP tablets daily. BAP values remained constant in the 3 and 6 tablet groups for 6–9 months during the follow-up study. The total serum bilirubin (T-bil) levels increased significantly at 3 (P=0.028) and 9 (P=0.0151) months and the red blood cell (RBC) count decreased at 6 months (P=0.0458) after intake for the 6 GTP tablet group. Alkaline phosphatase (ALP) levels increased significantly at 9 months (P=0.0298). Cholinesterase (ChE) decreased significantly at 9 (P= 0.0127) and 12 (P= 0.0207) months after intake for the 3 GTP tablet group. The results indicate that the daily intake of 6 GTP tablets containing 474 mg polyphenols significantly reduces HAI-induced oxidative stress in HCC or MLC patients while the antioxidative potentials of the patients remain constant.

Repercussões da radioterapia na região orofacial e seu tratamento

A radioterapia em região de cabeça e pescoço provoca inúmeras sequelas ao paciente irradiado, afetando o sistema estomatognático e com repercussões sistêmicas importantes. As sequelas da radiação ionizante podem ser extensas e, algumas vezes, permanentes, em especial nas glândulas salivares e no tecido ósseo. É relevante que o cirurgião dentista tenha conhecimento das reações adversas e das formas adequadas de prevenção e tratamento para amenizar o desconforto e melhorar a condição de vida do paciente irradiado. Portanto, a conscientização e motivação deste paciente, com a promoção de saúde oral através da adequação do meio bucal e orientações sobre ações preventivas, são essenciais para se obter o melhor prognóstico.

Vitamin e and N-acetylcysteine as antioxidant adjuvant therapy in children with acute lymphoblastic leukemia

Although cancer therapies have experienced great success nowadays, yet the associated toxic response and free radicals formation have resulted in significant number of treatment-induced deaths rather than disease-induced fatalities. Complications of chemotherapy have forced physicians to study antioxidant use as adjunctive treatment in cancer. This study aimed to evaluate the antioxidant role of vitamin E and N-acetyl cysteine (NAC) in overcoming treatment-induced toxicity in acute lymphoblastic leukaemia (ALL) during the intensive period of chemo-/radiotherapy, almost the first two months of treatment. Forty children newly diagnosed with ALL were enrolled in this study. Twenty children (group I) have taken vitamin E and NAC supplementations with chemotherapy and the other twenty children (group II) have not taken any adjuvant antioxidant therapy. They were evaluated clinically for the occurrence of complications and by the laboratory parameters (blood levels of glutathione peroxidase (Glu.PX) antioxidant enzyme, malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), liver enzymes, and bone marrow picture). Results revealed reduced chemotherapy and radiotherapy toxicity as evidenced by decreasing level of MDA, increasing level of Glu.Px and decreased occurrence of toxic hepatitis, haematological complications, and need for blood and platelet transfusions in group I compared to group II. We can conclude that vitamin E and NAC have been shown to be effective as antioxidant adjuvant therapy in children with ALL to reduce chemo-/radiotherapy-related toxicities during the initial period of treatment.

Antioxidants and Other Micronutrients in Complementary Oncology

Many patients being treated for cancer use micronutrient supplements, with the intention to complement their cancer treatment or help them cope with the therapy- and disease-associated side effects. The majority are adding antioxidants without the knowledge of the treating physician. There are many concerns that antioxidants might decrease the effectiveness of chemotherapy, but increasing evidence suggests a benefit when antioxidants are added to conventional cytotoxic therapies. However, it is imperative that physicians explore the use of antioxidant and other micronutrient supplements with their cancer patients and educate them about potentially negative as well as potentially beneficial effects.

Dietary supplement use in cancer care: help or harm

Conventional wisdom generally recommends complete avoidance of all dietary supplements, especially during chemotherapy and radiation. This interdiction persists, in spite of high rates of dietary supplement use by patients throughout all phases of cancer care, and can result in patients' perceptions of physicians as negative, thus leading to widespread nondisclosure of use. A review of the clinical literature shows that some evidence for harm does exist; however, data also exist that show benefit from using certain well-qualified supplements. Physicians should increase their knowledge base about dietary supplement use in cancer and consider all of the data when advising patients. Strategies that are patient-centered and reflect the complete array of available evidence lead to more nuanced messages about dietary supplement use in cancer. This should encourage greater disclosure of use by patients and ultimately increase safety and efficacy for patients choosing to use dietary supplements during cancer care.

Oxidative stress in ulcerative colitis-associated carcinogenesis

Oxidative stress is defined as an imbalance between generation of reactive oxygen species (ROS) and decreased antioxidant defense systems. Oxidative stress develops particularly in inflammatory reactions because the inflammatory cells, neutrophils, and macrophages produce large amounts of ROS. It has been known for a long time that oxidative stress in inflamed tissue can pave the way for malignant tumors, and that it is a major pathogenetic factor for the well-established correlation between inflammatory diseases and cancer. Oxidative stress has long been associated with the pathogenesis of chronic inflammatory bowel disease (IBD)-related colorectal cancer. This article provides an overview of the pathology of ROS and presents recent advances concerning the role of ROS in IBD-related colorectal carcinogenesis (Fig. 1).

Complementary and alternative therapies in pediatric oncology

Evidence on the science of complementary and alternative medicine (CAM) in children with cancer is slowly evolving. Most parents of children with cancer want their children to receive state-of-the-art therapy, which generally includes chemotherapy, radiation, and surgery. Increasingly, they also want the concomitant use of CAM therapies to help effect a cure or to alleviate symptoms. The ideal model of integrative pediatric oncology offers safe and effective CAM therapies in a pediatric hospital or medical center setting which participates in the clinical trials network of a pediatric oncology cooperative group setting.

Oxidative stress and apoptosis: impact on cancer therapy

It is well established that some chemotherapeutic agents and radiation therapy generate reactive oxygen species (ROS) in patients during cancer therapy. Free radicals, particularly ROS have been proposed as common mediators for apoptosis. Recent studies have demonstrated that the mode of cell death depends on the severity of the oxidative damage. This review will address some of the current paradigms of oxidative stress, and antioxidants on apoptosis, and discuss the potential mechanisms by which oxidants can regulate apoptotic pathways. It will also review new developments in eliminating cancer cells by selectively inducing apoptosis.

Do antioxidants interfere with radiation therapy for cancer?

Despite recent comprehensive review articles concluding that supplemental antioxidants do not undermine the effectiveness of cytotoxic therapies, the use of antioxidants during cancer treatment remains controversial. Many oncologists take the position that antioxidants by their nature undermine the free radical mechanism of chemotherapy and radiotherapy and should therefore generally be avoided during treatment. For their part, many integrative practitioners believe that antioxidants taken during cancer treatment not only alleviate some of the adverse effects of that treatment but also enhance the efficacy of cancer therapy. Until recently, research attention has focused primarily on the interaction of antioxidants with chemotherapy; relatively little attention has been paid to the interaction of antioxidants with radiotherapy. This article reviews the clinical literature that has addressed whether antioxidants do in fact interfere with radiation therapy. Studies have variously investigated the use of alpha-tocopherol for the amelioration of radiation-induced mucositis; pentoxifylline and vitamin E to correct the adverse effects of radiotherapy; melatonin alongside radiotherapy in the treatment of brain cancer; retinol palmitate as a treatment for radiation-induced proctopathy; a combination of antioxidants (and other naturopathic treatments) and external beam radiation therapy as definitive treatment for prostate cancer; and the use of synthetic antioxidants, amifostine, dexrazoxane, and mesna as radioprotectants. With few exceptions, most of the studies draw positive conclusions about the interaction of antioxidants and radiotherapy. Although further studies are needed, the preponderance of evidence supports a provisional conclusion that dietary antioxidants do not conflict with the use of radiotherapy in the treatment of a wide variety of cancers and may significantly mitigate the adverse effects of that treatment.

New developments and novel therapeutic perspectives for vitamin C

Vitamin C is required for collagen synthesis and biosynthesis of certain hormones and recommended dietary intake levels are largely based these requirements. However, to function effectively as an antioxidant (or a pro-oxidant), relatively high levels of this vitamin must be maintained in the body. The instability of vitamin C combined with its relatively poor intestinal absorption and ready excretion from the body reduce physiological availability of this vitamin. This inability to maintain high serum levels of vitamin C may have serious health implications and is particularly relevant in the onset and progression of degenerative disease, such as cancer and cardiovascular disease (CVD), which have a strong contributing oxidative damage factor. In this review, we examine recent studies on the regulation of transport mechanisms for vitamin C, related clinical ramifications, and potential implications in high-dose vitamin C therapy. We also evaluate recent clinical and scientific evidence on the effects of this vitamin on cancer and CVD, with focus on the key mechanisms of action that may contribute to the therapeutic potential of this vitamin in these diseases. Several animal models that could be utilized to address unresolved questions regarding the feasibility of vitamin C therapy are also discussed.

Hydroxyl radical scavenger ameliorates cisplatin-induced nephrotoxicity by preventing oxidative stress, redox state unbalance, impairment of energetic metabolism and apoptosis in rat kidney mitochondria

Nephrotoxicity is the major dose-limiting factor of cisplatin chemotherapy. Reactive oxygen species generated in mitochondria are thought to be the main cause of cellular damage in such injury. The present study examined, in vivo, the protective potential of the hydroxyl radical scavenger dimethylthiourea (DMTU) against cisplatin-induced effects on renal mitochondrial bioenergetics, redox state and oxidative stress. Adult male Wistar rats (200 to 220 g) were divided into four groups of eight animals each. The control group was treated only with an intraperitoneal (i.p.) injection of saline solution (1 ml/100 g body weight). The second group was given only DMTU (500 mg/kg body weight, i.p, followed by 125 mg/Kg, i.p., twice a day until they were killed). The third group was given a single injection of cisplatin (10 mg/kg body weight, i.p.). The fourth group was given DMTU (500 mg/kg body weight, i.p.), just before the cisplatin injection (10 mg/kg body weight, i.p.), followed by injections of DMTU (125 mg/kg body weight, i.p.) twice a day until they were killed. Animals were killed 72 h after the treatment. Besides not presenting any direct effect on mitochondria, DMTU substantially inhibited cisplatin-induced mitochondrial injury and cellular death by apoptosis, suppressing the occurrence of acute renal failure. All the following cisplatin-induced effects were prevented by DMTU: (1) increased plasmatic levels of creatinine and blood urea nitrogen (BUN); (2) decreased ATP content, calcium uptake and electrochemical potential; (3) oxidation of lipids, including cardiolipin; and oxidation of proteins, including sulfhydryl, and aconitase enzyme, as well as accumulation of carbonyl proteins; (4) depletion of the antioxidant defense (NADPH and GSH) and (5) increased activity of the apoptosis executioner caspase-3. Our findings show the important role played by mitochondria and hydroxyl radicals in cisplatin-induced nephrotoxicity, as well as the effectiveness of DMTU in preventing the renal mitochondrial damage caused by cisplatin. These results strongly suggest that protection of mitochondria by hydroxyl radical scavengers may be an interesting approach to prevent the kidney tissue damage caused by cisplatin-chemotherapy.