Profiling of CYP4Z1 and CYP1B1 expression in bladder cancers.

Bladder cancer is the tenth most common cancer worldwide, where its burden remains a challenge and needs new novel therapies. Several reports indicate expression of CYP4Z1 and CYP1B1 in many tumours. Their expressions are associated with a poor prognosis, and therefore proposed as promising biomarkers or targets for anticancer therapy. By using immunohistochemistry, expression of CYP4Z1 and CYP1B1 was evaluated in a panel of different types of bladder cancer, and the enzymes' relation to histopathological features were assessed. Results showed an increased expression of CYP4Z1 (54.3%) and CYP1B1 (76.9%) in the majority of bladder cancers compared to weak or lack of expression of both enzymes in normal tissues. CYP4Z1expression was significantly associated with tumour grade and stage where the expression was markedly increased in a high grade and advanced stage of the disease (p < 0.05). Additionally, CYP1B1 expression was also associated with TNM staging (p < 0.05) and its expression was increased in patients with lymph node metastasis. The expression profiles of CYP4Z1 and CYP1B1 suggest that both enzymes have the potential to be biomarkers or targets for novel anticancer therapy for bladder cancer. Nevertheless, further studies are needed to better delineate whether these enzymes are druggable targets.

Regulation of cytochrome P450 4F11 expression by liver X receptor alpha.

Cytochrome P450 4F (CYP4F) enzymes are responsible for the metabolism of eicosanoids, which play important roles in inflammation. Nuclear receptor liver X receptor alpha (LXRα) is a critical signal node connecting inflammation and lipid metabolism. Studies revealed that the release of cytokines and nuclear factor-κB (NF-κB) can change the CYP4F11 expression in HepG2 cells. However, the effect of LXRα on the CYP4F family and the underlying mechanism remain unclear. This study found that CYP4F11 is a target gene of LXRα. Luciferase assays and siRNA transfection showed that LXRα increased the transcription of CYP4F11 and LXRα agonist GW3965 could induce the expression of CYP4F11 by activating the LXRα-CYP4F11 pathway. Besides, overexpression of CYP4F11 could decrease TNF-α and IL-1ß in lipopolysaccharide (LPS)-induced THP-1 cells. The finding of the regulation of CYP4F11 may contribute to the anti-inflammatory activity of LXRα agonists.

Transcriptional factor six2 promotes the competitive endogenous RNA network between CYP4Z1 and pseudogene CYP4Z2P responsible for maintaining the stemness of breast cancer cells.

BACKGROUND: The expression of CYP4Z1 and the pseudogene CYP4Z2P has been shown to be specifically increased in breast cancer by our group and others. Additionally, we previously revealed the roles of the competitive endogenous RNA (ceRNA) network mediated by these genes (ceRNET_CC) in breast cancer angiogenesis, apoptosis, and tamoxifen resistance. However, the roles of ceRNET_CC in regulating the stemness of breast cancer cells and the mechanisms through which ceRNET_CC is regulated remain unclear. METHODS: Transcriptional factor six2, CYP4Z1-3'UTR, and CYP4Z2P-3'UTR were stably overexpressed or knocked down in breast cancer cells via lentivirus infection. ChIP-sequencing and RNA-sequencing analysis were performed to reveal the mechanism through which ceRNET_CC is regulated and the transcriptome change mediated by ceRNET_CC. Clinical samples were used to validate the correlation between six2 and ceRNET_CC. Finally, the effects of the six2/ceRNET_CC axis on the stemness of breast cancer cells and chemotherapy sensitivity were evaluated by in vitro and in vivo experiments. RESULTS: We revealed that ceRNET_CC promoted the stemness of breast cancer cells. Mechanistically, six2 activated ceRNET_CC by directly binding to their promoters, thus activating the downstream PI3K/Akt and ERK1/2 pathways. Finally, we demonstrated that the six2/ceRNET_CC axis was involved in chemoresistance. CONCLUSIONS: Our results uncover the mechanism through which ceRNET_CC is regulated, identify novel roles for the six2/ceRNET_CC axis in regulating the stemness of breast cancer cells, and propose the possibility of targeting the six2/ceRNET_CC axis to inhibit breast cancer stem cell (CSC) traits.

Arachidonic acid metabolites of CYP4A and CYP4F are altered in women with preeclampsia.

Few studies exist on cytochrome P450 (CYP450) metabolites of arachidonic acid (AA) pertaining to the pathophysiological events in pregnancy. We hypothesized that metabolism of AA via the CYP450 pathways is altered within the placenta in women with preeclampsia (PE) and contributes to the pathophysiology of the disease. Thus, placental vascular CYP450 enzyme expression and activity were measured in normal pregnant (NP) and preeclamptic (PE) patients. CYP450 isoform expression (CYP4A11, CYP4A22, CYP4F2, and CYP4F3) was found to be elevated within the placenta of women with PE compared to normal pregnant (NP) women and chronic hypertensive (CHTN) pregnant women. In addition, placental production of 20-HETE was significantly increased in PE women compared to both NP and CHTN women. Moreover, there was an imbalance in circulating 20-HETE:EETs in PE women. To examine whether alterations in CYP450 AA metabolism contribute to the altered placentation in PE, trophoblast function, proliferation and migration were assessed in the presence of exogenous 20-HETE and a 20-HETE specific synthesis inhibitor, HET0016. Trophoblast proliferation was significantly increased in the presence of 20-HETE (1 µM) and reduced with 20-HETE blockade by HET0016 (1 mM, 5 mM, and 10 mM). On the contrary, administration of exogenous 20-HETE (1 µM) significantly reduced trophoblast migration. In conclusion, metabolism of AA via CYP450 is altered in PE, and increased placental production of 20-HETE may contribute to the pathophysiology of the disease.

Expression of CYP4V2 in human THP1 macrophages and its transcriptional regulation by peroxisome proliferator-activated receptor gamma.

Because macrophages respond to a variety of pathological and pharmacological reagents, understanding the role of P450s in macrophages is important for therapeutic intervention. There has been a lack of research on CYP4 in macrophages, but fatty acid accumulation and lipid trafficking in macrophages have been suggested to be a main cause of atherosclerosis. All human CYP4 genes (n=12) were screened in THP1 macrophages by gene-specific reverse transcriptase-polymerase chain reaction (RT-PCR). Only CYP4V2 exhibited strong expression of both mRNA and protein. Expression levels of both CYP4V2 mRNA and protein were significantly reduced after treatment with peroxisome proliferator-activated receptor gamma (PPARγ) antagonist GW9662. However, the expression levels of CYP4V2 were not changed by PPARα antagonist (GW6471) and liver X receptor alpha antagonist (22-S hydroxycholesterol). A metabolite of the CYP4V2 enzyme, 12-hydroxydodecanoic acid, was detected in THP1 macrophages, and this metabolite was significantly decreased after treatment with the PPARγ inhibitor GW9662 (>80% decreased, p<0.05). In summary, fatty acid metabolizing protein CYP4V2 was identified in human THP1 macrophages, and its expression was regulated by PPARγ. Further study is required to understand the role of CYP4V2 with regard to fat accumulation in the activated macrophage and atherosclerotic plaque development.