## 4 Discussion
Nrf2-mediated antioxidant response was also promoted by H\({}_{2}\)O\({}_{2}\) evidenced by upregulation of _MGST3_ and _GSTA4/A2/M4_ involved in glutathione metabolism indicating disrupted redox status and promoted defense against oxidative stress. On the other hand, cellular cytoskeleton and integrity were disturbed by H\({}_{2}\)O\({}_{2}\) as cell adhesion molecules, adherens/tight junction, and focal adhesion pathways were downregulated. This is consistent with previous studies reported Caco-2 cells' injury and barrier dysfunction in response to oxidative stress, which contributes to IBD [139, 140]. In addition, intestinal crypt cells have the ability to initiate tumors if exposed to oxidative stress [113]. We demonstrated that H\({}_{2}\)O\({}_{2}\) treatment upregulated lipid uptake and metabolism as we observed upregulation of _FABP1_, _MTTP_, and _DGAT2_. We also observed that H\({}_{2}\)O\({}_{2}\) induced steroid hormone and steroid biosynthesis, which has been observed in studies of liver cells treated with H\({}_{2}\)O\({}_{2}\)[59, 141]. _LSS_, _DHCR24_, and _MSMO1_ involved in steroid biosynthesis were upregulated in H\({}_{2}\)O\({}_{2}\)-treated cells. Upregulation of steroid biosynthesis might suggest sustained tumorigenicity as cholesterol synthesis is considered a hallmark feature of cancer [142]. Steroid biosynthesis was not affected by 13-HPODE treatment; in fact, it has been previously reported that oxidized lipids could inhibit cholesterol synthesis by binding to SREBPs and suppressing their nuclear localization [143]. We observed that H\({}_{2}\)O\({}_{2}\) caused alteration of amino acids metabolism including upregulation of valine, leucine and isoleucine degradation pathway, which have also shown to be upregulated in MCF-7 cells treated with H\({}_{2}\)O\({}_{2}\); this pathway has been linked to volatile organic compounds, which are biomarkers for cancer [144]. Our findings suggest that H\({}_{2}\)O\({}_{2}\) might have a significant impact on intestinal tumor or crypt cells, which alters redox status and modifieslipid and amino acid metabolism as well as cell cytoskeleton affecting cellular physiology, integrity, and survival fates. Table 4 demonstrates comparative differential expression of selected genes between the three treatment groups. Collectively, our results indicated that 13-HPODE, LA and H2O2 upregulated the peroxisomal pathway and peroxisome-related genes including _PEX6_ and _CROT_. Although we observed upregulation of genes involved in PPAR signaling in both 13-HPODE- and LA-treated cells including _PLIN2_ and _HMGCS2_, the upregulation effect was more pronounced in 13-HPODE-treated cells. This may suggest that 13-HPODE is a more potent activator of PPAR signaling than LA although both oxidized and unoxidized LA have previously shown to activate PPARs [34; 76]. Moreover, gene expression and pathway analysis indicated that 13-HPODE and H2O2 promoted a powerful antioxidant response in PDiff cells compared to LA treatment. This was evidenced by upregulation of genes involved in cytochrome P450, Nrf2-mediated response, and glutathione metabolism, including _CAT_ and _GSTA2_, which might promote adaptive response. In addition, amino acid metabolism upregulation observed in 13-HPODE- and H2O2-treated cells, but not in LA-treated cells, might suggest that these two treatments could promote a tumorigenic environment as amino acid metabolism including serine biosynthesis has a role in cell survival [112]. 13-HPODE caused significant downregulation of oxidative phosphorylation, which was not seen in LA or H2O2 treatments indicating the damaging effect might be caused by 13-HPODE on mitochondrial function as reported by previous studies [123; 124]. As we mentioned earlier, all three treatments caused downregulation of ribosome biogenesis, spliceosome, and pyrimidine synthesis.