Hydroxyl safflower yellow A regulates the tumor immune microenvironment to produce an anticancer effect in a mouse model of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a serious threat to human health. Chemotherapy drugs such as cisplatin are widely used in cancer treatment, but can cause severe side effects. Hydroxyl safflower yellow A (HSYA) is a water-soluble chalcone glycoside substance extracted from safflowers (Carthamus tinctorius L.) that has been reported to inhibit tumor growth with few side effects. The tumor immune microenvironment is crucial for the proliferation and invasiveness of tumor cells, and it is mediated by forkhead box P3-positive (FOXP3+) regulatory T cells (Tregs) and retinoic acid receptor-related orphan receptor-gamma (ROR gamma)-expressing Th17 cells. FOXP3+ Tregs inhibit immunoreaction and FOXP3 is a key indicator of Tregs. ROR gamma isoform 2, also known as ROR gamma t, is an important transcription factor in Th17 cells that may promote cancer progression. In the present study, the antitumor effect of HSYA on HCC was investigated, as well as its impact on the tumor immune microenvironment. Following the establishment of a mouse model for HCC, hematoxylin and eosin staining were performed to observe histological changes in liver tumors, and the spleen and thymus were weighed to calculate the spleen and thymus indexes. The proportion of FOXP3+ Tregs in the spleen was determined by flow cytometry, and expression levels of Foxp3 and Ror gamma t were examined by reverse transcription-quantitative polymerase chain reaction and western blot analysis. The results of the present study showed that cisplatin inhibited tumor growth, caused weight loss and reduced the immunoreactivity of the mice. HSYA inhibited tumor growth without causing significant weight loss. The proportion of FOXP3-expressing Tregs in the spleen and the expression of Foxp3 and Ror gamma t mRNA decreased following treatment with certain doses of HSYA. In conclusion, HSYA inhibited tumor growth without detrimental effects on the weight of the mice, indicating that HSYA may be suitable as a novel therapy for HCC patients.