Considering the growing number of cancer cases around the world, natural products from the diet that exhibit potential antitumor properties are of interest. Our previous research demonstrated that fortification with iodine compounds is an effective way to improve the antioxidant potential of lettuce. The purpose of the present study was to evaluate the effect of iodine-biofortified lettuce on antitumor properties in human gastrointestinal cancer cell lines, gastric AGS and colon HT-29. Our results showed that extracts from iodine-biofortified lettuce reduce the viability and proliferation of gastric and colon cancer cells. The extracts mediated cell cycle arrest which was accompanied by inactivation of anti-apoptotic Bcl-2 and activation of caspases, as assessed by flow cytometry. However, extracts from lettuce fortified with organic forms of iodine acted more effectively than extracts from control and KIO3-enriched plants. Using quantitative PCR, we detected the increase in pro-apoptotic genes BAD, BAX and BID in AGS cells whereas up-regulation of cell cycle progression inhibitor CDKN2A and downregulation of pro-proliferative MDM2 in HT-29 cells. Interestingly, lettuce extracts led to down-regulation of pro-survival AKT1 and protooncogenic MDM2, which was consistent for extracts of lettuce fortified with organic form of iodine, 5-ISA, in both cell lines. MDM2 downregulation in HT-29 colon cancer cells was associated with RB1 upregulation upon 5-ISA-fortified lettuce extracts, which provides a link to the epigenetic regulation of tumor suppressor genes by RB/MDM2 pathway. Indeed, SEMA3A tumor suppressor gene was hypomethylated and upregulated in HT-29 cells treated with 5-ISA-fortified lettuce. Control lettuce exerted similar effects on RB/MDM2 pathway and SEMA3A epigenetic activation in HT-29 cells. Our findings suggest that lettuce as well as lettuce fortified with organic form of iodine, 5-ISA, may exert epigenetic anti-cancer effects that can be cancer type-specific.

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triple-negative breast cancer (tnBc) is a subtype of breast cancer unresponsive to traditional receptortargeted treatments, leading to a disproportionate number of deaths. invasive breast cancer is believed to evolve from non-invasive ductal carcinoma in situ (DciS). Detection of triple-negative DciS (tn-DciS) is challenging, therefore strategies to study molecular events governing progression of pre-invasive tn-DciS to invasive tnBc are needed. Here, we study a canine tn-DciS progression and investigate the DnA methylation landscape of normal breast tissue, atypical ductal hyperplasia (ADH), DciS and invasive breast cancer. We report hypo-and hypermethylation of genes within functional categories related to cancer such as transcriptional regulation, apoptosis, signal transduction, and cell migration. DnA methylation changes associated with cancer-related genes become more pronounced at invasive breast cancer stage. Importantly, we identify invasive-only and DCIS-specific DNA methylation alterations that could potentially determine which lesions progress to invasive cancer and which could remain as pre-invasive DciS. changes in DnA methylation during tn-DciS progression in this canine model correspond with gene expression patterns in human breast tissues. this study provides evidence for utilizing methylation status of gene candidates to define late-stage (DCIS and invasive), invasive stage only or DciS stage only of tn-DciS progression. Breast cancer is classified into subtypes based on the expression of growth factor receptors including the estrogen receptor (ER), the progesterone receptor (PR), and the receptor for human epidermal growth factor (HER-2) 1. Growth of breast tumors expressing any of these receptors may be controlled effectively by treatment in the adjuvant setting with receptor-targeted drugs 2. However, breast tumors that do not express any of these receptors have no known effective adjuvant treatment capable of controlling tumor growth. Such tumors are referred to as triple-negative breast cancers (TNBC) and are the most aggressive and lethal of all breast malignancies 2. TNBC accounts for 15% of breast cancer cases and a disproportionate percentage of breast cancer deaths among women 3. It has been shown that patients with TNBC have poor prognosis and shorter median time to relapse compared to patients with other subtypes of breast cancer 4. Ductal carcinoma in situ (DCIS) is defined as a non-invasive overgrowth of cells characterized by high proliferation within the breast ductal system. Studies suggest that triple-negative DCIS (TN-DCIS), a rare type of DCIS, is a precursor stage of invasive breast cancer 5,6. Therefore, early detection of TN-DCIS is important in preventing breast cancer cases that may progress to triple negative invasive carcinoma. However, TN-DCIS is challenging to detect at early stage in humans 7. Despite efforts to use immunohistochemistry to measure receptor expression in scientific studies of human DCIS tissues, detection of receptor status, including ER, is not routi...

Epigenetic aberrations are linked to sporadic breast cancer. Interestingly, certain dietary polyphenols with anti-cancer effects, such as pterostilbene (PTS), have been shown to regulate gene expression by altering epigenetic patterns. Our group has proposed the involvement of DNA methylation and DNA methyltransferase 3B (DNMT3B) as vital players in PTS-mediated suppression of candidate oncogenes and suggested a role of enhancers as target regions. In the present study, we assess a genome-wide impact of PTS on epigenetic marks at enhancers in highly invasive MCF10CA1a breast cancer cells. Following chromatin immunoprecipitation (ChIP)-sequencing in MCF10CA1a cells treated with 7 μM PTS for 9 days, we discovered that PTS leads to increased binding of DNMT3B at enhancers of 77 genes, and 17 of those genes display an overlapping decrease in the occupancy of trimethylation at lysine 36 of histone 3 (H3K36me3), a mark of active enhancers. We selected two genes, PITPNC1 and LINC00910, and found that their enhancers are hypermethylated in response to PTS. These changes coincided with the downregulation of gene expression. Of importance, we showed that 6 out of 17 target enhancers, including PITPNC1 and LINC00910, are bound by an oncogenic transcription factor OCT1 in MCF10CA1a cells. Indeed, the six enhancers corresponded to genes with established or putative cancer-driving functions. PTS led to a decrease in OCT1 binding at those enhancers, and OCT1 depletion resulted in PITPNC1 and LINC00910 downregulation, further demonstrating a role for OCT1 in transcriptional regulation. Our findings provide novel evidence for the epigenetic regulation of enhancer regions by dietary polyphenols in breast cancer cells.

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