Severe carbohydrate restriction augments the antiproliferative effect of hormonal therapy in a murine model of Ehrlich breast adenocarcinoma: histological and immunohistochemical investigations

Background

Malignant tumors of the breast are the most diagnosed cancers in females globally. Recent evidence suggests that carbohydrate restriction (CR), especially ketogenic diets, has become a potential treatment approach for many malignancies, including breast cancer. Tamoxifen (TAX) is a selective estrogen receptor modulator (ERM) that can reduce the risk of cancer recurrence. The current work was designed to assess the impact of CR on the proliferation of breast adenocarcinoma cells and to compare this impact with that of TAX. Study groups included: group 1: vehicle-treated mice; group 2: the Ehrlich group: injected Ehrlich ascites carcinoma (EAC) cells (2.5 × 10⁶) in 0.25 ml isotonic saline; group 3: CR group: mice were supplied with a diet regimen of severe CR throughout the study and injected EAC at week 7; group 4: hormonal therapy (HT) group: mice in this group injected with EAC at week 7 and then received TAX at a dose of 20 mg/kg 3 times/week orally for 3 weeks; and lastly group 5: the group of combined intervention. The mice in the CR, HT, and the combined groups received Ehrlich cancer cells at the same dose and route as the Ehrlich group.

Results

CR and HT groups demonstrated a significant decrease in levels of insulin-like growth factor (IGF-1), carbohydrate antigen (CA 15–3), hexokinase 2 (HK2), hypoxia-inducible factor-1 (HIF-1) α, and malondialdehyde (MDA) compared to the Ehrlich group. Additionally, the mean area % of caspase-3 was significantly increased, and the mean area % of Ki67 and estrogen receptor (ER)α was significantly decreased.

Conclusions

The combined treatment demonstrated the most advantageous outcome, as evidenced by reduced CA 15–3 levels, tumor size, and the mean area % of Ki67. This suggests that the addition of severe CR to the conventional therapy of breast cancer has a beneficial effect.