Antiangiogenic and hypolipidemic activity of coenzyme Q10 supplementation to breast cancer patients undergoing Tamoxifen therapy

Mechanism of ferroptosis in breast cancer and research progress of natural compounds regulating ferroptosis

Breast cancer is the most prevalent cancer worldwide and its incidence increases with age, posing a significant threat to women's health globally. Due to the clinical heterogeneity of breast cancer, the majority of patients develop drug resistance and metastasis following treatment. Ferroptosis, a form of programmed cell death dependent on iron, is characterized by the accumulation of lipid peroxides, elevated levels of iron ions and lipid peroxidation. The underlying mechanisms and signalling pathways associated with ferroptosis are intricate and interconnected, involving various proteins and enzymes such as the cystine/glutamate antiporter, glutathione peroxidase 4, ferroptosis inhibitor 1 and dihydroorotate dehydrogenase. Consequently, emerging research suggests that ferroptosis may offer a novel target for breast cancer treatment; however, the mechanisms of ferroptosis in breast cancer urgently require resolution. Additionally, certain natural compounds have been reported to induce ferroptosis, thereby interfering with breast cancer. Therefore, this review not only discusses the molecular mechanisms of multiple signalling pathways that mediate ferroptosis in breast cancer (including metastasis, invasion and proliferation) but also elaborates on the mechanisms by which natural compounds induce ferroptosis in breast cancer. Furthermore, this review summarizes potential compound types that may serve as ferroptosis inducers in future tumour cells, providing lead compounds for the development of ferroptosis-inducing agents. Last, this review proposes the potential synergy of combining natural compounds with traditional breast cancer drugs in the treatment of breast cancer, thereby suggesting future directions and offering new insights.

Emerging role of ferroptosis in breast cancer: New dawn for overcoming tumor progression

Breast cancer has become a serious threat to women's health. Cancer progression is mainly derived from resistance to apoptosis induced by procedures or therapies. Therefore, new drugs or models that can overcome apoptosis resistance should be identified. Ferroptosis is a recently identified mode of cell death characterized by excess reactive oxygen species-induced lipid peroxidation. Since ferroptosis is distinct from apoptosis, necrosis and autophagy, its induction successfully eliminates cancer cells that are resistant to other modes of cell death. Therefore, ferroptosis may become a new direction around which to design breast cancer treatment. Unfortunately, the complete appearance of ferroptosis in breast cancer has not yet been fully elucidated. Furthermore, whether ferroptosis inducers can be used in combination with traditional anti- breast cancer drugs is still unknown. Moreover, a summary of ferroptosis in breast cancer progression and therapy is currently not available. In this review, we discuss the roles of ferroptosis-associated modulators glutathione, glutathione peroxidase 4, iron, nuclear factor erythroid-2 related factor-2, superoxide dismutases, lipoxygenase and coenzyme Q in breast cancer. Furthermore, we provide evidence that traditional drugs against breast cancer induce ferroptosis, and that ferroptosis inducers eliminate breast cancer cells. Finally, we put forward prospect of using ferroptosis inducers in breast cancer therapy, and predict possible obstacles and corresponding solutions. This review will deepen our understanding of the relationship between ferroptosis and breast cancer, and provide new insights into breast cancer-related therapeutic strategies.

Effects of coenzyme Q10 supplementation on inflammation, angiogenesis, and oxidative stress in breast cancer patients: a systematic review and meta-analysis of randomized controlled- trials

BACKGROUND/OBJECTIVE

Systemic inflammation and oxidative stress (OS) are associated with breast cancer. CoQ10 as an adjuvant treatment with conventional anti-cancer chemotherapy has been demonstrated to help in the inflammatory process and OS. This systematic review and meta-analysis of randomized clinical trials (RCTs) aimed to evaluate the efficacy of CoQ10 supplementation on levels of inflammatory markers, OS parameters, and matrix metalloproteinases/tissue inhibitor of metalloproteinases (MMPs/TIMPs) in patients with breast cancer.

METHODS

A systematic literature search was carried out using electronic databases, including PubMed, Web of Science, Scopus, Google Scholar, and Embase, up to December 2020 to identify eligible RCTs evaluating the effect of CoQ10 supplementation on OS biomarkers, inflammatory cytokines, and MMPs/TIMPs. From 827 potential reports, 5 eligible studies consisting of 9 trials were finally included in the current meta-analysis. Quality assessment and heterogeneity tests of the selected trials were performed using the PRISMA checklist protocol and the I2 statistic, respectively. Fixed and random-effects models were assessed based on the heterogeneity tests, and pooled data were determined as the standardized mean difference (SMD) with a 95% confidence interval (CI).

RESULTS

Our meta-analysis of the pooled findings for inflammatory biomarkers of OS and MMPs showed that CoQ10 supplementation (100 mg/day for 45-90 days) significantly decreased the levels of VEGF [SMD: - 1.88, 95% CI: (- 2. 62 to - 1.13); I2 = 93.1%, p < 0.001], IL-8 [SMD: - 2.24, 95% CI: (- 2.68 to - 1.8); I2 = 79.6%, p = 0.001], MMP-2 [SMD: - 1.49, 95% CI: (- 1.85 to - 1.14); I2 = 76.3%, p = 0.005] and MMP-9 [SMD: - 1.58, 95% CI: (- 1.97 to - 1.19); I2 = 79.6%, p = 0.002], but no significant difference was observed between CoQ10 supplementation and control group on TNF-α [SMD: - 2.30, 95% CI: (- 2.50 to - 2.11); I2 = 21.8%, p = 0.280], IL-6 [SMD: - 1.56, 95% CI: (- 1.73 to - 1.39); I2 = 0.0%, p = 0.683], IL-1β [SMD: - 3.34, 95% CI: (- 3.58 to - 3.11); I2 = 0.0%, p = 0.561], catalase (CAT) [SMD: 1.40, 95% CI: (1.15 to 1.65); I2 = 0.0%, p = 0.598], superoxide dismutase (SOD) [SMD: 2.42, 95% CI: (2.12 to 2.71); I2 = 0.0%, p = 0.986], glutathione peroxidase (GPx) [SMD: 2.80, 95% CI: (2.49 to 3.11); I2 = 0.0%, p = 0.543]], glutathione (GSH) [SMD: 4.71, 95% CI: (4.26 to 5.16); I2 = 6.1%, p = 0.302] and thiobarbituric acid reactive substances (TBARS) [SMD: - 3.20, 95% CI: (- 3.53 to - 2.86); I2 = 29.7%, p = 0.233].

CONCLUSION

Overall, the findings showed that CoQ10 supplementation reduced some of the important markers of inflammation and MMPs in patients with breast cancer. However, further studies with controlled trials for other types of cancer are needed to better understand and confirm the effect of CoQ10 on tumor therapy.

Coenzyme Q10 in breast cancer care

INTRODUCTION

Breast cancer (BC) is the most common type of cancers with high rates of morbidity and mortality. By now numerous medical approaches are available for treatment of BC including chemotherapies, radiation and surgery. These are accompanied by several complications like partial effectiveness, fatal adverse effects and high cost. Numerous studies in recent years tried to find safe and effective alternatives. A promising candidate is coenzyme Q10 which is an antioxidant that can target the mechanisms of BC tumor progression.

METHODS & RESULTS

In this systematic review via PubMed searching, sparse but promising findings were classified about the successful application of this compound as an adjunct in prevention and treatment of BC and its comorbidities with some contradicting data about its null effect.

DISCUSSION & CONCLUSION

According to the results, further well-designed clinical studies with dose optimization are now required to stratify the role of this supplement in current BC regimens.

Topical Coenzyme Q10 demonstrates mitochondrial-mediated neuroprotection in a rodent model of ocular hypertension

Coenzyme Q10 (CoQ10) is a mitochondrial-targeted antioxidant with known neuroprotective activity. Its ocular effects when co-solubilised with α-tocopherol polyethylene glycol succinate (TPGS) were evaluated. In vitro studies confirmed that CoQ10 was significantly protective in different retinal ganglion cell (RGC) models. In vivo studies in Adult Dark Agouti (DA) rats with unilateral surgically-induced ocular hypertension (OHT) treated with either CoQ10/TPGS micelles or TPGS vehicle twice daily for three weeks were performed, following which retinal cell health was assessed in vivo using DARC (Detection of Apoptotic Retinal Cells) and post-mortem with Brn3a histological assessment on whole retinal mounts. CoQ10/TPGS showed a significant neuroprotective effect compared to control with DARC (p<0.05) and Brn3 (p<0.01). Topical CoQ10 appears an effective therapy preventing RGC apoptosis and loss in glaucoma-related models.

Serum coenzyme Q₁₀, α-tocopherol, γ-tocopherol, and C-reactive protein levels and body mass index in adolescent and premenopausal females

OBJECTIVE

Lipid-soluble antioxidants are associated with a lower incidence for many chronic diseases of aging, possibly by preventing damage from chronic inflammation. In the current study, we compared serum levels of coenzyme Q₁₀ (CoQ₁₀), α-tocopherol, γ-tocopherol, and C-reactive protein (CRP) between adolescent girls and premenopausal women to assess changes from childhood to midlife.

METHODS

Baseline serum CoQ₁₀, α-tocopherol, γ-tocopherol, and CRP levels were measured in 207 girls (13-19 years) and 183 premenopausal women (34-47 years) using standard methods and the 2 age groups were compared by t test. The influence of age, body mass index (BMI), and race/ethnicity and interaction effects on serum values were assessed using analysis of covariance. Pearson correlation coefficients were used to assess associations between pairs of lipid micronutrients.

RESULTS

Overall, adolescent girls had significantly lower mean serum CoQ₁₀, α-tocopherol, γ-tocopherol, and CRP levels relative to premenopausal women (CoQ10: 376 vs 544 ng/mL, p < 0.0001; α-tocopherol: 6.9 vs 13.5 μg/mL, p < 0.0001; γ-tocopherol: 1.3 vs 1.7 μg/mL, p < 0.0001; CRP: 1.29 vs 2.13 mg/L, p < 0.0001). The differences in CoQ₁₀ and tocopherols remained significant after adjustment for BMI and race/ethnicity. CoQ₁₀ was significantly and positively correlated to α- and γ-tocopherol, and BMI was positively associated with CRP and γ-tocopherol in both groups.

CONCLUSIONS

Lower serum CoQ₁₀, α-tocopherol, γ-tocopherol, and CRP levels in adolescent girls compared to women suggests that adolescents may have a reduced need for antioxidants possibly due to their lower BMI and inflammatory status as indicated by CRP.

Low plasma coenzyme Q(10) levels and breast cancer risk in Chinese women

BACKGROUND

Low circulating levels of coenzyme Q(10) (CoQ(10)) have been associated with increased cancer incidence and poor prognosis for a number of cancer types, while a recent prospective study observed a positive association for CoQ(10) with breast cancer risk.

METHODS

We prospectively examined the association of plasma CoQ(10) with breast cancer risk in a nested case-control study of Chinese women within the Shanghai Women's Health Study (SWHS). Prediagnostic plasma samples were obtained from 340 cases and 653 age-matched controls and analyzed for total CoQ(10).

RESULTS

A borderline significant inverse association for breast cancer incidence with plasma CoQ(10) level was observed by a conditional logistic regression model adjusted for age and age at first live birth, which became significant after elimination of cases diagnosed within 1 year of blood draw (P(trend) = 0.03). This association was independent of menopausal status. Plasma CoQ(10) levels were also observed to be significantly associated with circulating γ-tocopherol (r = 0.50; P < 0.0001) and α-tocopherol (r = 0.38; P < 0.0001) levels.

CONCLUSIONS

Circulating levels of CoQ(10) were generally low in this population and the observed association with breast cancer risk may be limited to those women with exceptionally low values.

IMPACT

This study reports an inverse relationship between circulating CoQ(10) and breast cancer risk, while the only other prospective study of CoQ(10) and breast cancer to date found a positive association. Lower levels of CoQ(10) in the SWHS population suggest that the 2 studies may not be contradictory and indicate a possible nonlinear (U-shaped) association of CoQ(10) with risk.

Coenzyme Q10: Clinical Update and Bioavailability

Coenzyme Q10 (CoQ 10) supplementation has been reported to be beneficial in treating a variety of health conditions and diseases, with more than 200 clinical trials investigating its use as a drug or dietary supplement. Numerous reviews of the safety and clinical potential of CoQ10 have been published. Successful treatment and efficacy is dependent on the bioavailability of CoQ 10, which is well known to be poor because of its lipophilic nature and large molecular weight. A number of recent clinical trials on CoQ 10 have investigated new formulations of CoQ10 for improvements in absorption and bioavailability. This review provides an update of clinical efficacy trials using CoQ10 and describes recent advances in formulation technology to improve the bioavailability of CoQ10. The authors also discuss a new method to improve the standards of reporting the bioavailability results of such advanced CoQ10 formulations to help clinicians and consumers make informed decisions.

Exogenous coenzyme Q10 modulates MMP-2 activity in MCF-7 cell line as a breast cancer cellular model

Background/Aims

Matrix Metalloproteinases 2 is a key molecule in cellular invasion and metastasis. Mitochondrial ROS has been established as a mediator of MMP activity. Coenzyme Q₁₀ contributes to intracellular ROS regulation. Coenzyme Q₁₀ beneficial effects on cancer are still in controversy but there are indications of Coenzyme Q₁₀ complementing effect on tamoxifen receiving breast cancer patients.

Methods

In this study we aimed to investigate the correlation of the effects of co-incubation of coenzyme Q10 and N-acetyl-L-cysteine (NAC) on intracellular H2O2 content and Matrix Metalloproteinase 2 (MMP-2) activity in MCF-7 cell line.

Results and Discussion

Our experiment was designed to assess the effect in a time and dose related manner. Gelatin zymography and Flowcytometric measurement of H2O2 by 2'7',-dichlorofluorescin-diacetate probe were employed. The results showed that both coenzyme Q10 and N-acetyl-L-cysteine reduce MMP-2 activity along with the pro-oxidant capacity of the MCF-7 cell in a dose proportionate manner.

Conclusions

Collectively, the present study highlights the significance of Coenzyme Q₁₀ effect on the cell invasion/metastasis effecter molecules.

[Complementary medicine in oncology]

In cancer therapy vastly different kinds of treatment regimens, but as a rule scientifically validated and reviewed, play a central role dependent on the tumor entity. Besides the options of schoolbook medicine complementary, alternative and supportive treatment options are becoming more frequently used in routine clinical practice. Numerous concepts and agents, partly verified in studies and partly based on empirical experiences are being applied. It is our intention to give a survey of the most common agents and concepts and to point out the risks and capabilities.

Improved survival in patients with end-stage cancer treated with coenzyme Q(10) and other antioxidants: a pilot study

This pilot study evaluated the survival of patients with end-stage cancer who received supplements of coenzyme Q(10) and a mixture of other antioxidants (e.g. vitamin C, selenium, folic acid and beta-carotene). During a period of 9 years, 41 patients who had end-stage cancer were included. Forty patients were followed until death and one patient was lost to follow-up and presumed dead. Primary cancers were located in the breast, brain, lungs, kidneys, pancreas, oesophagus, stomach, colon, prostate, ovaries and skin. The median predicted survival time was calculated from Kaplan-Meier curves for each patient at inclusion. Median predicted survival was 12 months (range 3 - 29 months), whereas median actual survival was 17 months (1 - 120 months), which is > 40% longer than the median predicted survival. Mean actual survival was 28.8 months versus 11.9 months for mean predicted survival. Ten patients (24%) survived for less time than predicted, whereas 31 (76%) survived for longer. Treatments were very well tolerated with few adverse effects.

Clinical aspects of coenzyme Q10: an update

The fundamental role of coenzyme Q(10) (CoQ(10)) in mitochondrial bioenergetics and its well-acknowledged antioxidant properties constitute the basis for its clinical applications, although some of its effects may be related to a gene induction mechanism. Cardiovascular disease is still the main field of study and the latest findings confirm a role of CoQ(10) in improving endothelial function. The possible relation between CoQ(10) deficiency and statin side effects is highly debated, particularly the key issue of whether CoQ(10) supplementation counteracts statin myalgias. Furthermore, in cardiac patients, plasma CoQ(10) was found to be an independent predictor of mortality. Studies on CoQ(10) and physical exercise have confirmed its effect in improving subjective fatigue sensation and physical performance and in opposing exercise-related damage. In the field of mitochondrial myopathies, primary CoQ(10) deficiencies have been identified, involving different genes of the CoQ(10) biosynthetic pathway; some of these conditions were found to be highly responsive to CoQ(10) administration. The initial observations of CoQ(10) effects in Parkinson's and Huntington's diseases have been extended to Friedreich's ataxia, where CoQ(10) and other quinones have been tested. CoQ(10) is presently being used in a large phase III trial in Parkinson's disease. CoQ(10) has been found to improve sperm count and motility on asthenozoospermia. Moreover, for the first time CoQ(10) was found to decrease the incidence of preeclampsia in pregnancy. The ability of CoQ(10) to mitigate headache symptoms in adults was also verified in pediatric and adolescent populations.