The current study was designed to investigate the effect of crocetin on the proliferation inhibition of colon cancer cells and the underlying mechanism. MTT assay showed inhibition of proliferation of colon cancer cells in a dose based manner by crocetin treatment. At 30 µM concentration of crocetin proliferation rate of colon cancer cells was reduced to 14% after 24 h.

Flow cytometry and fluorescence microscopy revealed induction of apoptosis in colon cancer cells on treatment with crocetin. The tube formation was suppressed significantly in the cultures of HUVEC treated with 30 µM concentration of crocetin compared to the control cultures.

The results from transwell assay revealed a significant reduction in the population of DU-145 cells passing through filters of transwell on treatment with crocetin compared to the control cells. Treatment of the DU-145 cells with crocetin caused a significant reduction in the expression levels of NF-κB, VEGF, and MMP-9.

The results from RT-PCR analysis revealed a significant reduction in the expression of genes involved in inflammation including, HMGB1, IL-6, and IL-8 on the treatment of DU-145 cells with crocetin. However, the expression of NAG-1 gene was increased by crocetin treatment in DU-145 cells significantly compared to the control cells.

Colon cancer cells

Crocetin inhibits the growth of colon cancer cells and prevents tube formation through induction of apoptosis. Therefore, crocetin can be used efficiently for the treatment of colon cancer.

Colon cancer, malignant tumor in the lining of the colon is the leading cause of deaths arising due to cancer and a challenge to clinicians throughout the world. Among the colon cancer patients around 15% have been found to possess liver metastases even at the time of diagnosis.

Thus the development of novel treatment strategies for colon cancer demands the identification of new molecules. In the current study effect of crocetin on proliferation, invasion and metastasis potential of colon cancer cells was investigated.

The results demonstrated that crocetin treatment inhibits colon cancer cell proliferation through downregulation of inflammatory gene expression. There are reports that crocetin treatment causes inhibition of cell proliferation in various types of carcinoma cells including, breast, gastric and colon cancer cells.

In the current study, crocetin treatment of colon cancer cells inhibited proliferation significantly (p < 0.05) at 10 µM concentration. The processes like carcinoma cell angiogenesis and invasion are major factors contributing to the metastasis of cancer cells to the distant organs.

The current study demonstrated that tube formation was suppressed significantly in the cultures of HUVEC treated with 30 µM concentration of crocetin compared to the control cultures.

The results from trans good assay revealed a significant reduction in the population of DU-145 cells passing through filters of trans well on treatment with crocetin compared to the control cells. Hereditary as well as environmental factors lead to chronic inflammation and contribute towards the carcinoma progression.

Crocetin is a potent antioxidant and anti-inflammatory agent. The results revealed a significant reduction in the expression of genes associated with inflammation like HMGB1, interleukin-6, and interleukin-8 on the treatment of colon cancer cells with crocetin. The expression of NAG-1 gene was increased by crocetin treatment in DU-145 cells significantly compared to the control cells.