Poly(ADP-ribose) polymerase-1 polymorphisms, expression and activity in selected human tumour cell lines

Abstract

BACKGROUND: Poly(ADP-ribose) polymerase-1 (PARP-1) is a DNA-binding enzyme activated by DNA breaks and involved in DNA repair and other cellular processes. Poly(ADP-ribose) polymerase activity can be higher in cancer than in adjacent normal tissue, but cancer predisposition is reported to be greater in individuals with a single-nucleotide polymorphism (SNP) V762A (T2444C) in the catalytic domain that reduces PARP-1 activity. METHODS: To resolve these divergent observations, we determined PARP-1 polymorphisms, PARP-1 protein expression and activity in a panel of 19 solid and haematological, adult and paediatric human cancer cell lines. RESULTS: There was a wide variation in PARP activity in the cell line panel (coefficient of variation, CV ¼ 103%), with the lowest and the highest activity being 2460 pmol PAR/10 6 (HS-5 cells) and 85 750 pmol PAR/10 6 (NGP cells). Lower variation (CV ¼ 32%) was observed in PARP-1 protein expression with the lowest expression being 2.0 ng mg À1 (HS-5 cells) and the highest being 7.1 ng mg À1 (ML-1 cells). The mean activity in the cancer cells was 45-fold higher than the mean activity in normal human lymphocytes and the PARP-1 protein levels were 23-fold higher. CONCLUSIONS: Surprisingly, there was no significant correlation between PARP activity and PARP-1 protein level or the investigated polymorphisms, T2444C and CA.

Variations in the mRNA expression of poly(ADP‐ribose) polymerases, poly(ADP‐ribose) glycohydrolase and ADP‐ribosylhydrolase 3 in breast tumors and impact on clinical outcome

“…protein levels was found in a panel of human tumor cell lines, 30 while a weak correlation was reported in peripheral blood mononuclear cells (PBMCs) from cancer patients (R 2 5 0.06, p 5 0.01) and a stronger correlation (R 2 5 0.19, p 5 0.003) in PBMCs from cancer patients. 31 In the small subset of 31 tumors for which frozen tissues were available in this present study, no correlation was noted between PARP1 mRNA and the level of full length PARP-1 protein but unfortunately suitable samples were not available from this retrospective series to assess PARP activity.…”

Evaluation of the radiosensitizing potency of chemotherapeutic agents in prostate cancer cells

“…The activity of the DNA repair enzyme, poly(ADP-ribose)-polymerase [PARP], is generally greater in cancer cells than in normal cells (Zaremba et al 2009). Inhibitors of PARP improve the efficiency and selectivity of DNA-damaging agents (Calabrese et al 2004).…”

Biomarkers of PARP inhibitor sensitivity

“…PARP1 protein levels do not differ between isogenic pairs of HR deficient and proficient cancers [22], and moreover there is in vitro evidence that PARP1 levels do not correlate with PARP1 activity [23]. In contrast, PARP activity is substantially increased in HR deficient cancers; In vitro PARP1 is hyperactive in HR deficient cell lines [22].…”