IDDF2022-ABS-0078 Baitouweng decoction ameliorates colitis-associated colorectal cancer by inhibiting hedgehog signaling cascade

Background

Baitouweng Decoction (BD), prescribed by a medical saint named Zhang Zhongjing, is a famous Chinese medicinal formula composed of Pulsatillae Radix, Phellodendri Chinensis Cortex, Coptidis Rhizoma and Fraxini Cortex, for the treatment of dysentery. Emerging evidence reveals that BD exhibits strong potency against colitis-associated colorectal cancer (CAC), with the underlying mechanisms elusive. Deregulated Hedgehog signaling pathway is implicated in the initiation and progression of many cancers, including CAC. Herein, we trove to explore the pharmacological effects of BD on CAC and its in-depth mechanisms on the basis of the Hedgehog signaling cascade.

Methods

Following the establishment of the mouse model of CAC with AOM (azoxymethane)/DSS (dextran sulfate sodium), BD was administered to the mice by intragastrical gavage, followed by an assessment of the efficacies of BD on the oncogenesis, DAI (disease activity index), apoptosis and Hedgehog signaling pathway activity in CAC tissue. In HCT116 colonic cancer cells, the effects of BD on the proliferation, migration, apoptosis and Hedgehog signaling axis were also examined.

Results

BD drastically ameliorated AOM/DSS-incurred CAC in mice, with more body weight gain and lowered DAI. TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assay indicated that BD significantly induced apoptosis in mouse CAC tissue, with decreased expression of anti-apoptotic BCL-2 (B-cell lymphoma 2) and increased level of pro-apoptotic BAX (BCL-2-associated X). Additionally, BD mitigated the levels of SHH (sonic Hedgehog), smoothened, Gli1 (glioma-associated oncogene 1) and c-Myc, but augmented SUFU (suppressor of fused homolog) expression in CAC tissue, evidenced by the analyses of qRT-PCR, western blot and immunohistochemistry. In HCT116 cells, BD sharply restrained the proliferation and migration. Flow cytometric analysis and Hoechst 33342/Propidium Iodide staining showed that BD caused apoptosis of HCT116 cells, with enhanced expression of BAX and attenuated level of BCL-2. Furthermore, compared with the control, BD strikingly lessened the mRNA and protein levels of SHH, smoothened, Gli1 and c-Myc, and raised those of SUFU in HCT116 cells.

Conclusions

BD inhibits CAC by suppressing Hedgehog signaling cascade, paving an approach for the application of BD to the treatment of CAC in the clinical setting.