Anticancer effect of dentatin and dentatin-hydroxypropyl-β-cyclodextrin complex on human colon cancer (HT-29) cell line

Ashwaq Shakir AL-Abboodi,1,2 Abdullah Rasedee,3 Ahmad Bustamam Abdul,1,4 Yun Hin Taufiq-Yap,5 Wafaa Abd Alwahed Alkaby,6 Mostafa Saddam Ghaji,7 Peter M Waziri,1,8 Mothanna Sadiq Al-Qubaisi1 1MAKNA-UPM, Cancer Research Laboratory, Institute of Bioscience, University Putra Malaysia, Serdang, Malaysia; 2Basic Science Branch, Faculty of Dentistry, University of Al-Qadisiyah, Al Diwaniyah, Iraq; 3Department of Veterinary Laboratory Diagnosis, Faculty of Veterinary Medicine, University Putra Malaysia, Serdang, Malaysia; 4Department of Biomedical Science, Faculty of Medicine and Health Science, University Putra Malaysia, Serdang, Malaysia; 5Department of Chemistry, Faculty of Science, University Putra Malaysia, Serdang, Malaysia; 6Department of Biomedical, Faculty of Biotechnology, University of AL-Qadisiyah, Al Diwaniyah, Iraq; 7Department of Anatomy and Histology, Faculty of Veterinary Medicine, University of Basrah, Basrah, Iraq; 8Department of Biochemistry, Kaduna State University, Main Campus,  Kaduna, Nigeria Introduction: Dentatin (DEN) (5-methoxy-2, 2-dimethyl-10-(1, 1-dimethyl-2propenyl) dipyran-2-one), a natural compound present in the roots of Clausena excavata Burm f, possesses pro-apoptotic and antiproliferative effects in various cancer cells. Because of its hydrophobicity, it is believed that its complexation with hydroxy-β-cyclodextrin (HPβCD) will make it a potent inhibitor of cancer cell growth. In the current work, the molecular mechanisms of apoptosis induced by DEN and DEN-HPβCD complex were demonstrated in human colon HT-29 cancer cells.Materials and methods: After the human colon HT-29 cancer cells were treated with DEN and DEN-HPβCD complex, their effects on the expression of apoptotic-regulated gene markers in mitochondria-mediated apoptotic and death receptor pathways were detected by Western blot analysis and reverse transcription polymerase chain reaction. These markers included caspases-9, 3, and 8, cytochrome c, poly (ADP-ribose) polymerase, p53, p21, cyclin A as well as the Bcl-2 family of proteins.Results: At 3, 6, 12, and 24 µg/mL exposure, DEN and DEN-HPβCD complex significantly affected apoptosis in HT-29 cells through the down-regulation of Bcl-2 and cyclin A in turn, and up-regulation of Bax, p53, p21, cytochrome c at both protein and mRNA levels. DEN and DEN-HPβCD complex also decreased cleaved poly (ADP-ribose) polymerase and induced caspases-3, -8, and -9.Conclusion: Results of this study indicate that the apoptotic pathway caused by DEN and DEN-HPβCD complex are mediated by the regulation of caspases and Bcl-2 families in human colon HT-29 cancer cells. The results also suggest that DEN-HPβCD complex may have chemotherapeutic benefits for colon cancer patients. Keywords: natural products, HPβCD, apoptosis, pro-apoptotic proteins, anti-apoptotic protein