Antitumor, antioxidant, and anti-inflammatory activity of spirulina against 7,12-dimethylbenzanthracene-induced mammary cancer

Background
Breast cancer is the most abundant malignancies worldwide; however, its current therapies encounter drug resistance or exhibit numerous side effects. Marine and freshwater algal biomasses, such as spirulina, are rich with many biological active components.
Objective
The main objective of the current study was to investigate the therapeutic, antioxidant, and immune-modulating efficiency of spirulina on breast tumor modelled female rats, especially through the inhibition of the phosphoinositide 3-kinases/Akt/mammalian target of rapamycin pathway.
Materials and methods
7,12-dimethylbenzanthracene (DMBA)-induced mammary cancer rats were ingested with spirulina (500 mg/kg/day) for 6 weeks, then blood and tissue samples of normal and spirulina-treated cancer rats were obtained and tested for biochemical, immunological, and histopathological assessments.
Results
The results showed that spirulina is rich in phenolic compounds that have high scavenger activity and reducing power reflecting the antioxidant potential of spirulina. Treatment of DMBA-induced mammary cancer rats with spirulina resulted in improvement in mammary oxidative stress status that was distorted due to DMBA administration; meanwhile, superoxide dismutase, glutathione peroxidase, and reduced glutathione values were elevated significantly coupled with a marked drop in nitric oxide and malondialdehyde levels. In addition, spirulina boosts the immune-modulating response against tumor as the serum proinflammatory cytokines (tumor necrosis factor alpha, interlukin-1 beta, and interlukin-6) were markedly downregulated, and associated with inhibition of Akt and mammalian target of rapamycin pathway; this in turn suppress the tumor proliferation and progression. Furthermore, the prognosis of the treatment was indicated by the clear reduction of serum cancer antigen 15.3 level accompanied by elevation in serum level of the apoptotic biomarkers (caspase-3 and CD4) inferring the upregulation of tumor suppressor genes. Similarly, spirulina ameliorated lipid profile and the biochemical markers of hepatorenal functions (alanine transaminase, aspartate transaminase, urea, and creatinine) that were disturbed by DMBA; therefore, it has a positive impact on the body health. These biochemical improvements were associated with a notable improvement in the histological architecture of the mammary tissue.
Conclusion
In conclusion, spirulina has proved considerable antitumor, antioxidant, and anti-inflammatory activities against DMBA-induced mammary cancer.