Xihuang Pill enhances anticancer effect of anlotinib by regulating gut microbiota composition and tumor angiogenesis pathway.

Lung cancer poses a serious threat to human health. Although targeted therapies have led to breakthroughs in the treatment of lung cancer, drug resistance and side effects limit their clinical applications. Xihuang pill (XHW), a classical anti-cancer traditional Chinese medicine formula, has been clinically proven to be an effective complementary therapy in the treatment of various of cancers. However, the underlying mechanism for its use in combination with anti-cancer drugs remains unclear. Here, we explored the anti-lung cancer effect of XHW combined with anlotinib in mice bearing Lewis lung cancer (LLC). We used gut microbiota and transcriptomics to elucidate the regulatory properties of XHW in improving anti-lung cancer effect of anlotinib. The results showed that combination treatment of XHW with Anlotinib significantly inhibited tumor growth in LLC-bearing mice. We found that XHW played a key role in the regulation of gut microbiota using 16 s rRNA sequencing analysis. Specifically, XHW increased the proportion of the beneficial bacteria Bacteroides and g_norank_f_Muribaculaceae. Based on transcriptomic analysis of tumor tissues, differentially expressed genes in the combination therapy group were related to biological processes concerning angiogenesis, such as regulation of blood vessel diameter, regulation of tube diameter, and regulation of tube size. Our data suggest that XWH enhances the anticancer effect of anlotinib by regulating gut microbiota composition and tumor angiogenesis pathway. Combination therapy with anlotinib and XHW may be a novel therapeutic strategy for lung cancer patients.