Identification of anti-metastatic drug and natural compound targets in isogenic colorectal cancer cells.

Therapeutic strategies for cancer treatment often remain challenging due to the cumulative risk derived from metastasis, which has been described as an aggressive state of cancer cell proliferation often resulting in failure of clinical therapy. In the current study, anti-metastatic properties of three chemotherapeutic drugs and three compounds from natural sources were investigated by comparative proteomic analysis. Proteomic profile comparison of the isogenic primary and metastatic colon cancer cell lines SW480 and SW620 identified two potential metastasis related molecular targets: fatty acid synthase and histone H4. To demonstrate their biological roles in cancer metastasis, the expression of these target genes was suppressed by siRNA transfection. Subsequent cell migration assays demonstrated reduced migratory effects. SW620 cells were treated with six anti-cancerous components. Through comprehensive proteomic analysis, three of the tested compounds, oxaliplatin, ginsenoside 20(S)-Rg3 and curcumin, were revealed to have a suppressive effect on FASN and histone H4 expression. SW620 cells treated with these drugs showed significantly reduced migratory activity, which suggests that drug-induced targeted suppression of these genes may affect cell migration. The validity of the proteomic datasets was verified by knowledgebase pathway analysis and immunoblotting assays. The anti-metastatic components revealed by the current proteomic analysis represent promising chemotherapeutic candidates for the treatment of colorectal adenocarcinoma. BIOLOGICAL SIGNIFICANCE: The current study demonstrates anti-metastatic activity of chemotherapeutics and natural components by the suppression of target molecules, fatty acid synthase and histone H4 identified by a comparative proteomic analysis employing the isogenic primary and metastatic colon cancer cell lines, SW480 and SW620. Three tested drugs, namely, oxaliplatin, ginsenoside 20(S)-Rg3 and curcumin were revealed to possess suppressive effects on fatty acid synthase and histone H4 and reduce metastasis as determined by cell migration assay. Data were confirmed by the correlation between spectral counts from proteomic data and Western blot analysis, which were in good agreement with immunohistochemistry.