Pre-Clinical Insights into the Iron and Breast Cancer Hypothesis

Population studies, systematic reviews, and meta-analyses have revealed no relationship between iron status and breast cancer, a weak positive association, or a small protective effect of low iron status. However, in those studies, the authors concluded that further investigation was merited. The set of experiments reported here used preclinical models to assess the likely value of further investigation. The effects of iron status on the initiation and promotion stage of mammary carcinogenesis are reported. Using the classical model of cancer initiation in the mammary gland, 7,12 dimethyl-benz[α]anthracene-induced carcinogenesis was unaffected by iron status. Similarly, excess iron intake showed no effect on the promotion stage of 1-methyl-1-nitrosurea-induced mammary carcinogenesis, though iron deficiency exerted a specific inhibitory effect on the carcinogenic process. Though iron-mediated cellular oxidation is frequently cited as a potential mechanism for effects on breast cancer, no evidence of increased oxidative damage to DNA attributable to excess iron intake was found. The reported preclinical data fail to provide convincing evidence that the further evaluation of the iron–breast cancer risk hypotheses is warranted and underscore the value of redefining the referent group in population-based studies of iron–cancer hypotheses in other tissues.

Capsaicin Encapsulated Chitosan Nanoparticles Augments Anticarcinogenic and Antiproliferative Competency Against 7,12 Dimethylbenz(a)anthracene Induced Experimental Rat Mammary Carcinogenesis

Background: Capsaicin is a powerful phytochemical spotted in chilies, starkly tied up with a bunch of health benefits but its clinical applications in cancer therapy are limited due to its poor solubility, and low bioavailability. Nanotechnology offers a strategy to discover new formulations for hydrophobic agent. Aim: The main intent of the current research was to investigate the effect of Capsaicin encapsulated chitosan nanoparticles (CAP@CS-NP) on 7,12-Dimethylbenz(a)anthracene (DMBA) induced mammary carcinogenesis in rats. Methodology: Mammary tumor was induced in female rats by injecting DMBA (25mg/kg b.wt) at the first week of the experiment. After 7 weeks, CAP@CS-NP (4mg/kg b.wt) was administered orally to DMBA induced tumor bearing rats for 21 days (thrice per week). The experiment was terminated at the end of the 14th week and their plasma and tissue sections were analyzed. Results: We found that significantly elevated levels of lipid peroxidation and diminished levels of antioxidant status in plasma, liver and mammary tissues. Increased levels of detoxification phase I enzymes and dropped levels of phase II enzymes in liver and mammary tissues in DMBA induced tumor bearing rats. As a result, oral administration of CAP@CS-NP suppressed the tumor growth, significantly raised body weight and restored abnormal enzymatic levels to near normal ranges. Additionally, histopathological and immunohistochemical analysis were also confirmed that CAP@CS-NP protects DMBA mediated cellular disruption and also inhibits abnormal cell proliferation. Conclusion: These findings suggest that nano encapsulation of CAP@CS-NP could be useful in targeted drug delivery and act as a promising chemotherapeutic agent to treat mammary carcinogenesis.

Development of mammary cancer in γ-irradiated F1 hybrids of susceptible Sprague-Dawley and resistant Copenhagen rats, with copy-number losses that pinpoint potential tumor suppressors

Copenhagen rats are highly resistant to mammary carcinogenesis, even after treatment with chemical carcinogens and hormones; most studies indicate that this is a dominant genetic trait. To test whether this trait is also dominant after radiation exposure, we characterized the susceptibility of irradiated Copenhagen rats to mammary carcinogenesis, as well as its inheritance, and identified tumor-suppressor genes that, when inactivated or mutated, may contribute to carcinogenesis. To this end, mammary cancer–susceptible Sprague-Dawley rats, resistant Copenhagen rats, and their F1 hybrids were irradiated with 4 Gy of γ-rays, and tumor development was monitored. Copy-number variations and allelic imbalances of genomic DNA were studied using microarrays and PCR analysis of polymorphic markers. Gene expression was assessed by quantitative PCR in normal tissues and induced mammary cancers of F1 rats. Irradiated Copenhagen rats exhibited a very low incidence of mammary cancer. Unexpectedly, this resistance trait did not show dominant inheritance in F1 rats; rather, they exhibited intermediate susceptibility levels (i.e., between those of their parent strains). The susceptibility of irradiated F1 rats to the development of benign mammary tumors (i.e., fibroadenoma and adenoma) was also intermediate. Copy-number losses were frequently observed in chromosome regions 1q52–54 (24%), 2q12–15 (33%), and 3q31–42 (24%), as were focal (38%) and whole (29%) losses of chromosome 5. Some of these chromosomal regions exhibited allelic imbalances. Many cancer-related genes within these regions were downregulated in mammary tumors as compared with normal mammary tissue. Some of the chromosomal losses identified have not been reported previously in chemically induced models, implying a novel mechanism inherent to the irradiated model. Based on these findings, Sprague-Dawley × Copenhagen F1 rats offer a useful model for exploring genes responsible for radiation-induced mammary cancer, which apparently are mainly located in specific regions of chromosomes 1, 2, 3 and 5.

Strategic Developments & Future Perspective on Gene Therapy for Breast Cancer: Role of mTOR and Brk/ PTK6 as Molecular Targets

Breast cancer is a serious health issue and a major concern in biomedical research. Alteration in major signaling (viz. PI3K-AKT-mTOR, Ras-Raf-MEK-Erk, NF-kB, cyclin D1, JAK-STAT, Wnt, Notch, Hedgehog signaling and apoptotic pathway) contributes to the development of major subtypes of mammary carcinoma such as HER2 positive, TNBC, luminal A and B and normal-like breast cancer. Further, mutation and expression parameters of different genes involved in the growth and development of cells play an important role in the progress of different types of carcinoma, making gene therapy an emerging new therapeutic approach for the management of life-threatening diseases like cancer. The genetic targets (oncogenes and tumor suppressor genes) play a major role in the formation of a tumor. Brk/PTK6 and mTOR are two central molecules that are involved in the regulation of numerous signaling related to cell growth, proliferation, angiogenesis, survival, invasion, metastasis, apoptosis, and autophagy. Since these two proteins are highly upregulated in mammary carcinogenesis, this can be used as targeted genes for the treatment of breast cancer. However, not much work has been done on them. This review highlights the therapeutic significance of Brk and mTOR and their associated signaling in mammary carcinogenesis, which may provide a strategy to develop gene therapy for breast cancer management.