title: PAC down-regulates estrogen receptor alpha and suppresses epithelial-to-mesenchymal transition in breast cancer cells.
abstract: Triple-negative breast cancer (TNBC) is an aggressive histological subtype with limited treatment options and very poor prognosis following progression after standard chemotherapeutic regimens. Therefore, novel molecules and therapeutic options are urgently needed for this category of patients. Recently, we have identified PAC as a curcumin analogue with potent anti-cancer features.
  
  
  
  HPLC was used to evaluate the stability of PAC and curcumin in PBS and also in circulating blood. Cytotoxicity/apoptosis was assessed in different breast cancer cell lines using propidium iodide/annexinV associated with flow cytometry. Furthermore, immunoblotting analysis determined the effects of PAC on different oncogenic proteins and pathways. Additionally, the real time xCELLigence RTCA technology was applied to investigate the effect of PAC on the cellular proliferation, migration and invasion capacities.
  
  
  
  PAC is more stable than curcumin in PBS and in circulating blood. Furthermore, we have shown differential sensitivity of estrogen receptor-alfa positive (ERα(+)) and estrogen receptor alfa negative (ERα(-)) breast cancer cells to PAC, which down-regulated ERα in both cell types. This led to complete disappearance of ERα in ERα(-) cells, which express very low level of this receptor. Interestingly, specific down-regulation of ERα in receptor positive cells increased the apoptotic response of these cells to PAC, confirming that ERα inhibits PAC-dependent induction of apoptosis, which could be mediated through ERα down-regulation. Additionally, PAC inhibited the proliferation and suppressed the epithelial-to-mesenchymal transition process in breast cancer cells, with higher efficiency on the TNBC subtype. This effect was also observed in vivo on tumor xenografts. Additionally, PAC suppressed the expression/secretion of 2 important cytokines IL-6 and MCP-1, and consequently inhibited the paracrine procarcinogenic effects of breast cancer cells on breast stromal fibroblasts.
  
  
  
  These results indicate that PAC could be considered as important candidate for future therapeutic options against the devastating TNBC subtype.
authors.affiliation: Department of Molecular Oncology, King Faisal Specialist Hospital and Research Center, MBC # 03, PO BOX 3354, Riyadh, 11211, Kingdom of Saudi Arabia.
authors.forename: Huda A
authors.initials: HA
authors.lastname: Al-Howail
authors.affiliation: Department of Molecular Oncology, King Faisal Specialist Hospital and Research Center, MBC # 03, PO BOX 3354, Riyadh, 11211, Kingdom of Saudi Arabia.|Department of Zoology, College of Science, King Saud University, Riyadh, 11451, Kingdom of Saudi Arabia.|Present Address: McGill University Health Center, Montreal, QC, Canada.
authors.forename: Hana A
authors.initials: HA
authors.lastname: Hakami
authors.affiliation: Department of Cyclotron and Radiopharmaceuticals, King Faisal Specialist Hospital and Research Center, Riyadh, 11211, Kingdom of Saudi Arabia.
authors.forename: Basem
authors.initials: B
authors.lastname: Al-Otaibi
authors.affiliation: Stem Cell Therapy Program, King Faisal Specialist Hospital and Research Center, Riyadh, 11211, Kingdom of Saudi Arabia.
authors.forename: Amer
authors.initials: A
authors.lastname: Al-Mazrou
authors.affiliation: Department of Zoology, College of Science, King Saud University, Riyadh, 11451, Kingdom of Saudi Arabia.
authors.forename: Maha H
authors.initials: MH
authors.lastname: Daghestani
authors.affiliation: Department of Cyclotron and Radiopharmaceuticals, King Faisal Specialist Hospital and Research Center, Riyadh, 11211, Kingdom of Saudi Arabia.
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Al-Jammaz
authors.affiliation: Department of Molecular Oncology, King Faisal Specialist Hospital and Research Center, MBC # 03, PO BOX 3354, Riyadh, 11211, Kingdom of Saudi Arabia.|The National Center for Genomics Research, King Abdulaziz City for Science and Technology, Riyadh, 11211, Kingdom of Saudi Arabia.
authors.forename: Huda H
authors.initials: HH
authors.lastname: Al-Khalaf
authors.affiliation: Department of Molecular Oncology, King Faisal Specialist Hospital and Research Center, MBC # 03, PO BOX 3354, Riyadh, 11211, Kingdom of Saudi Arabia. aboussekhra@kfshrc.edu.sa.
authors.forename: Abdelilah
authors.initials: A
authors.lastname: Aboussekhra
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000494:pharmacology; D001597:Benzylidene Compounds / Q000008:administration & dosage* / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018932:Chemokine CCL2 / Q000378:metabolism; D003474:Curcumin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D004355:Drug Stability; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D051379:Mice; D010881:Piperidones / Q000008:administration & dosage* / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D064726:Triple Negative Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: C568297:5-bis(4-hydroxy-3-methoxybenzylidene)-N-methyl-4-piperidone; D000970:Antineoplastic Agents; D001597:Benzylidene Compounds; C111835:CCL2 protein, human; D018932:Chemokine CCL2; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; C508600:IL6 protein, human; D015850:Interleukin-6; D010881:Piperidones; D003474:Curcumin
keywords: Breast cancer; EMT; ERα; PAC