[Show abstract][Hide abstract] ABSTRACT: Treatment of advanced-stage cervical cancers with (chemo)radiation causes cytotoxicity through induction of high levels of DNA damage. Tumour cells respond to DNA damage by activation of the 'DNA damage response' (DDR), which induces DNA repair and may counteract chemoradiation efficacy. Here, we investigated DDR components as potential therapeutic targets and verified the predictive and prognostic value of DDR activation in patients with cervical cancer treated with (chemo)radiation. In a panel of cervical cancer cell lines, inactivation of ataxia telangiectasia mutated (ATM) or its substrate p53-binding protein-1 (53BP1) clearly gave rise to cell cycle defects in response to irradiation. Concordantly, clonogenic survival analysis revealed that ATM inhibition, but not 53BP1 depletion, strongly radiosensitised cervical cancer cells. In contrast, ATM inhibition did not radiosensitise non-transformed epithelial cells or non-transformed BJ fibroblasts. Interestingly, high levels of active ATM prior to irradiation were related with increased radioresistance. To test whether active ATM in tumours prior to treatment also resulted in resistance to therapy, immunohistochemistry was performed on tumour material of patients with advanced-stage cervical cancer (n = 375) treated with (chemo)radiation. High levels of phosphorylated (p-)ATM [p = 0.006, hazard ratio (HR) = 1.817] were related to poor locoregional disease-free survival. Furthermore, high levels of p-ATM predicted shorter disease-specific survival (p = 0.038, HR = 1.418). The presence of phosphorylated 53BP1 was associated with p-ATM (p = 0.001, odds ratio = 2.206) but was not related to any clinicopathological features or survival. In conclusion, both our in vitro and patient-related findings indicate a protective role for ATM in response to (chemo)radiation in cervical cancer and point at ATM inhibition as a possible means to improve the efficacy of (chemo)radiation.
Full-text · Article · Nov 2012 · International Journal of Cancer
[Show abstract][Hide abstract] ABSTRACT: Presence of pelvic lymph node metastases is the main prognostic factor in early-stage cervical cancer patients, primarily treated with surgery. Aim of this study was to identify cellular tumor pathways associated with pelvic lymph node metastasis in early-stage cervical cancer.
Gene expression profiles (Affymetrix U133 plus 2.0) of 20 patients with negative (N(0)) and 19 with positive lymph nodes (N(+)), were compared with gene sets that represent all 285 presently available pathway signatures. Validation immunostaining of tumors of 274 consecutive early-stage cervical cancer patients was performed for representatives of the identified pathways.
Analysis of 285 pathways resulted in identification of five pathways (TGF-β, NFAT, ALK, BAD, and PAR1) that were dysregulated in the N(0), and two pathways (β-catenin and Glycosphingolipid Biosynthesis Neo Lactoseries) in the N(+) group. Class comparison analysis revealed that five of 149 genes that were most significantly differentially expressed between N(0) and N(+) tumors (P < 0.001) were involved in β-catenin signaling (TCF4, CTNNAL1, CTNND1/p120, DKK3, and WNT5a). Immunohistochemical validation of two well-known cellular tumor pathways (TGF-β and β-catenin) confirmed that the TGF-β pathway (positivity of Smad4) was related to N(0) (OR: 0.20, 95% CI: 0.06-0.66) and the β-catenin pathway (p120 positivity) to N(+) (OR: 1.79, 95%CI: 1.05-3.05).
Our study provides new, validated insights in the molecular mechanism of lymph node metastasis in cervical cancer. Pathway analysis of the microarray expression profile suggested that the TGF-β and p120-associated noncanonical β-catenin pathways are important in pelvic lymph node metastasis in early-stage cervical cancer.
Full-text · Article · Mar 2011 · Clinical Cancer Research
[Show abstract][Hide abstract] ABSTRACT: The objective of this study is to correlate the expression of epidermal growth factor receptor (EGFR) components with clinical behavior of early-stage cervical cancer. Tissue samples of 336 consecutive Federation of International Gynecologists and Obstetricians stage IB-IIA cervical cancer patients all treated primarily by radical surgery were collected. Clinicopathologic and follow-up data were prospectively obtained during standard treatment and follow-up. As representatives for the EGFR pathway, expression of EGFR, pEGFR, PTEN, pAKT, and pERK was assessed by immunohistochemistry on tissue microarrays. Positive immunostaining was observed for EGFR in 32.1%, for pEGFR in 21.0%, for PTEN in 38.3%, for pAKT in 5.3%, and for pERK in 4.3% of tumor samples. Positive EGFR immunostaining was associated with squamous cell carcinoma of the cervix (odds ratio [OR], 7.41; 95% confidence interval [CI], 3.38-16.23, P < .001), negative pEGFR immunostaining with poor differentiation (OR, 0.39; 95% CI, 0.20-0.73, P = .004), and negative PTEN immunostaining with metastatic pelvic lymph nodes (OR, 0.51; 95% CI, 0.30-0.90, P = .019). In multivariate analysis, only pelvic lymph node metastasis (hazard ratio, 6.11; 95% CI, 3.46-10.77, P < .001) and poor differentiation (hazard ratio, 1.91; 95% CI, 1.12-3.26, P = .018) were related to disease-specific survival. In early-stage cervical cancer, loss of PTEN expression is associated with pelvic lymph node metastasis, suggesting PTEN to be one of the tumor suppressor genes affecting pelvic lymph node metastasis. However, expression of EGFR pathway components does not appear to have prognostic impact in surgically treated early-stage cervical cancer.