Abstract A65: Caspase 14 is a target of black-raspberry-mediated inhibition of human cervical cancer cell proliferation

Abstract

Abstract Cervical cancer is the second most common female cancer worldwide and the seventh leading cause of cancer death in women. While significant advances have been made in early detection, it remains a challenge to manage pre-invasive and invasive cervical lesions. However, the long latency of cervical cancer development allows for the investigation and utilization of preventive and therapeutic interventions, including chemopreventive approaches. Phytochemical-based cancer chemoprevention and the role of bioactive food components have attracted significant interest due to their dramatic anti-proliferative and anti-tumorigenesis effects observed in preclinical studies. We have previously demonstrated that an extract of lyophilized black raspberries (LBR, Rubus occidentalis) inhibited the proliferation of human cervical cancer cell lines: HeLa (HPV16−/HPV18+, adenocarcinoma), SiHa (HPV16+/HPV18−, squamous cell carcinoma) and C-33A (HPV16−/HPV18−, squamous cell carcinoma) in a dose- and time-dependent manner. Here we investigate the modulation of apoptotic pathways as a potential mechanism. Expression profiling of 93 apoptosis-related genes was performed with the Applied Biosystems' TaqMan Gene Signature Human Apoptosis Array in HeLa, SiHa and C-33A human cervical cancer cells treated with vehicle control (0.02% DMSO) or LBR (200µg/mL) for 1 and 3 days. The following genes were differentially expressed (≥2-fold change) in a manner favorable to cancer prevention following LBR treatment: CARD9 (+4.4) and BCL2L10 (−4.0) in HeLa cells; BIRC1 (−2.3) and CASP14 (+4.2) in SiHa cells; CARD15 (+3.4), TNFRSF1B (+2.8), TNFRSF1A (+2.3), FADD (+2.3), BBC3 (+2.1), BOK (+2.1), RELB (+2.1), IKBKG (+2.0), HTRA2 (+2.0), DEDD2 (+2.0), BAD (+2.0) and BAX (+2.0) in C-33A cells. Two candidate genes from each cell line were chosen for subsequent validation: CARD9 and BCL2L10 in HeLa cells, BIRC1 and CASP14 in SiHa cells, FADD and BAX in C-33A cells. From these selected candidate genes, only CASP14 was validated as a >2-fold expression change (+5.1) following LBR exposure in SiHa cells. CASP14 mRNA expression was undetectable (>40 Ct values) in both HeLa and C-33A cells. Caspase 14, a cysteine-aspartic proteases, is directly involved in epithelial cell differentiation, and only indirectly with canonical apoptotic pathways. Caspase 14 plays a role in epithelial cell malignant transformation, and is progressive loss during cervical cancer progression. Consequently, up-regulation of CASP14 expression by LBR in cervical cancer cells may provide a potential mechanism for attenuating cervical carcinogenesis and progression. Further studies will define the contribution of CASP14 mRNA and protein up-regulation following LBR exposure in cervical cancer cells. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A65.