New explanation for why sulforaphane has anti-tumor effect
In a paper published in the Journal of Nutritional Biochemistry, a team of researchers from Oregon State University and the Texas A&M Health Science Center has demonstrated that a natural compound found in certain vegetables is able to attenuate the expression of cancer-associated long noncoding RNAs (IncRNAs), a finding that will advance the understanding of how diet impacts our health.
Sulforaphane, abbreviated as SFN, is a chemical compound found in cruciferous vegetables, such as broccoli, cabbage, cauliflower, and kale. It is an antioxidant and stimulators of natural detoxifying enzymes and has anti-tumor effect. Previous studies have shown that SFN reduces the risk of breast, bladder, and prostate cancer. Now the new study adds to the growing evidence showing SFN has health benefits.
IncRNAs are a type of noncoding RNAs (ncRNAs) that exceed 200 nucleotides in length. Although most IncRNAs have not been characterized thoroughly, a significant number of them have been found to exhibit association with human diseases, including cancer.
To date, how diet influences the expression of IncRNAs remains elusive. To address this problem, Emily Ho, a professor of Oregon State University and the leader researcher of the study, and colleagues set out to investigate the impact of the dietary SFN on IncRNAs.
They analyzed whole-genome RNA-sequencing data of normal human prostate epithelial cells and prostate cancer cells treated with SFN or dimethylsulfoxide. Results showed that SFN dramatically changed the expression of about 100 IncRNAs in each cell type and normalized the levels of some IncRNAs that were differentially expressed in cancer cells.
The researchers also found that one IncRNA called LINC01116 was upregulated in several cancers and was reduced after SFN treatment. Further, LINC01116 knockdown inhibited the proliferation of prostate cancer cells and increased the expression of certain genes, including GAPDH, MAP1LC3B2, and H2AFY. When LINC01116 was disrupted through gene editing, the cancer cells were less likely to form colonies. Collectively, the findings suggest that LINC01116 may have an oncogenic function.
Research on IncRNAs is still at a preliminary stage. Given that lncRNAs are important regulators of gene expression and seem to be involved in multiple cellular activities, alterations in IncRNA expression may be associated with many diseases processes. Identifying which factors impact IncRNA expression may lead to a better understanding of disease progression and open up a new avenue of drug discovery.