Anticancer role of mango (Mangifera indica L.) peel and seed kernel extracts against 7,12- dimethylbenz[a]anthracene-induced mammary carcinogenesis in female rats

Abstract

Breast cancer is the second leading cause of cancer death among women. The present study is an effort to reveal the antiproliferative and antioxidant actions of mango seed kernel extract (KE), peel extract (PE), and their combination (KEPE) on mammary tumors induced by 7,12 dimethylbenz[a]anthracene (DMBA). Seven groups of adult female Sprague-Dawley rats were prepared, including C: (control), DMBA: (rats were administered with DMBA), (DMBA-KE), (DMBA-PE), and (DMBA-KEPE): rats were administered with DMBA and then treated with KE, PE, and (both KE and PE), respectively, (KE) and (PE): rats were administered with KE and PE, separately. The study focused on the assessment of markers of endocrine derangement [serum 17-β estradiol (E2)], apoptosis [caspase-3 and deoxyribonucleic acid fragmentation (DNAF)], and oxidative stress [lipid peroxidation and antioxidants (glutathione, glutathione-S-transferase, glutathione reductase, glutathione peroxidase, and superoxide dismutase)]. Histopathological examination and immunohistochemical expression of caspase-3 and estrogen receptor-α (ER-α) in mammary gland tissues (MGTs) were determined, as well as the characterization of mango extracts. The results showed that DMBA administration induced mammary tumors by increasing cell proliferation and evading apoptosis. In addition, DMBA administration caused oxidative stress by the production of reactive oxygen species, which increased lipid peroxidation and decreased cellular antioxidants, allowing cancer to progress. In contrast, treatment with DMBA-KE, DMBA-PE, or DMBA-KEPE diminished mammary tumors induced by DMBA, where they reduced oxidative stress via increased antioxidant parameters including reduced glutathione, superoxide dismutase, total glutathione peroxidase, glutathione reductase, and glutathione S-transferase. Also, different treatments decreased proliferation through the reduction of E2, and ER-α expression levels. However, these treatments increased the apoptosis of unwanted cells as they increased caspase-3 activity and DNAF. All these changes led to the prevention of breast injuries and the reduction of mammary tumors. This demonstrates that the contents of mango extracts, especially phenolics and flavonoids, have an important role in mammary tumor treatment through their potential antioxidant, antiproliferative, proapoptotic, and anti-estrogenic effects. KE and PE administration for 4 weeks had no adverse effects. Conclusion: Each of KE, PE, and KEPE has a therapeutic effect against DMBA-induced mammary tumors via induction of apoptosis and reduction of each of the OS, proliferation, and estrogenic effects. So, they can play an important role in the pharmacological tole.

Figure 1

HPLC analysis of polyphenolic compounds in PE and KE (a & b).

Figure 2

Effect of 7, 12- Dimethyl-benz[a]anthracene (DMBA), KE, PE, and (KEPE) on the total body weight and weight of mammary glands. (A): total body weight; (B): weight of right MGT and (C): weight of left MGT. Where group C-control: rats were administered orally with a single dose of 4 ml sesame oil/kg bm; group (DMBA): rats were administered orally with (80 mg/kg) of DMBA as a single dose; group (DMBA-KE): rats treated with KE for 4 weeks after the 9th week of DMBA administration; group (DMBA-PE): rats treated with PE for 4 weeks after the 9th week of DMBA administration; group (DMBA-KEPE): rats treated with both KE and PE for 4 weeks after the 9th week of DMBA administration; group (KE): rats treated with KE only for 4 weeks; group (PE): rats treated with PE only for 4 weeks. Results are given as means ± S. D. for seven rats. Values with different letters are significantly different at p ≤ 0.05 (a: Significant with C group; b: Significant with DMBA group; c: Significant with DMBA-KE group; d: Significant with DMBA-PE group; e: Significant with DMBA-KEPE group; f: Significant with KE group).

Figure 3

Effect of 7, 12- Dimethyl-benz[a]anthracene (D), KE, PE, and (KEPE) on the markers of apoptosis and oxidative stress. Caspase-3 activity (a); percentage of DNA fragmentation (b); MDA (c); GSH (d); SOD activity (e); t-GPx activity (f); GSR activity (g) and GST activity (h) in rat mammary gland tissues. Where group C-control: rats were administered orally with a single dose of 4 ml sesame oil/kg bm; group (DMBA): rats were administered orally with (80 mg/kg) of DMBA as a single dose; group (DMBA-KE): rats treated with KE for 4 weeks after the 9th week of DMBA administration; group (DMBA-PE): rats treated with PE for 4 weeks after the 9th week of DMBA administration; group (DMBA-KEPE): rats treated with both KE and PE for 4 weeks after the 9th week of DMBA administration; group (KE): rats treated with KE only for 4 weeks; group (PE): rats treated with PE only for 4 weeks. Results are given as means ± S.D. for seven rats. Values with different letters are significantly different at p ≤ 0.05 (a: Significant with C group; b: Significant with DMBA group; c: Significant with DMBA-KE group; d: Significant with DMBA-PE group; e: Significant with DMBA-KEPE group; f: Significant with KE group).

Figure 4

Histopathological examination of mammary gland tissues in different studied groups. The C group (A) shows normal mammary gland tissue. DMBA group (B) shows dilated duct containing inspissated secretions (arrow) and atypical epithelial cells. DMBA-KE group (C) reveals proliferated dilated breast ducts (arrows) embedded into fat tissue with no residual tumor tissue. DMBA-PE group (D1) shows lobular architecture with a ductal carcinoma focus (arrow), and (D2) reveals lymph nodes showing reactive changes. DMBA-KEPE group (E) revealed breast tissue with a focus showing atypical cells (arrow). KE group (F) and PE group (G) show normal branched breast ducts within fat tissue (arrows). Figure 4A,B,C,D2,F,G: H & E stain × 100. Figure 4D1,E: H & E stain × 400.

Figure 5

Photomicrographs of ER-ir in mammary gland tissues of different studied groups. The immunohistochemical expression of ER-α in MGTs sections showed a varying degree of positive and negative reactions for ER-α (Fig. 5a1–a8).

Figure 6

Photomicrographs of Caspase-3-ir in mammary gland tissues of different studied groups. The immunohistochemical expression of caspase-3 in mammary gland tissue sections revealed a varying degree of positive and negative reactions for caspase-3 (Fig. 6a1–a7).

Figure 7

Presents the research's conclusions as a whole.

Figure 8

Experimental design and animal groups. The rats were divided into seven groups of twelve rats each. Sham control group (C): the rats were administered a single oral dose of 4 ml sesame oil/kg bm using oral gavage. DMBA group: the rats were administered with DMBA to induce mammary gland carcinoma. (DMBA-KE), (DMBA-PE) and (DMBA-KEPE) groups: the rats were administered with DMBA. Then after the ninth week of induction of mammary gland carcinoma, the rats were treated with KE, PE, and (KE and PE), respectively, for 4 weeks. KE and PE groups: the healthy rats were administered orally KE and PE, respectively, for 4 weeks.