No abstract

A genetic background has been implicated in the development of prostate cancer. Protein microarrays have enabled the identification of proteins, some of which associated with apoptosis, that may play a role in the development of such a tumor. Inhibition of apoptosis is a co-factor that contributes to the onset and progression of prostate cancer, though the molecular mechanisms are not entirely understood. Poly (ADP-ribose) polymerase 1 (PARP-1) gene is required for translocation of the apoptosis-inducing factor (AIF) from the mitochondria to the nucleus. Hence, it is involved in programmed cell death. Different PARP-1 gene expression has been observed in various tumors such as glioblastoma, lung, ovarian, endometrial, and skin cancers. We evaluated the expression of PARP-1 protein in prostatic cancer and normal prostate tissues by immunohistochemistry in 40 men with prostate cancer and in 37 normal men. Positive nuclear PARP-1 staining was found in all samples (normal prostate and prostate cancer tissues). No cytoplasmic staining was observed in any sample. PARP-1-positive cells resulted significantly higher in patients with prostate carcinoma compared with controls (P<0.001). PARP-1 over-expression in prostate cancer tissue compared with normal prostate suggests a greater activity of PARP-1 in these tumors. These findings suggest that PARP-1 expression in prostate cancer is an attempt to trigger apoptosis in this type of tumor similarly to what reported in other cancers.

Background An understanding of the activated protein signaling architecture in non–small-cell lung cancer (NSCLC) is of critical importance to the development of new therapeutic approaches and identification of predictive and prognostic biomarkers for patient stratification. Methods We used reverse-phase protein microarrays to map the activated protein signaling networks of 47 NSCLC tumors, 28 of which were node negative, which were subjected to tumor cellular enrichment using laser capture microdissection. The phosphorylation/cleavage levels of 111 key signaling proteins and total levels of 17 proteins were measured for broadscale signaling analysis. Results Pathway activation mapping of NSCLC revealed distinct subgroups composed of epidermal growth factor receptor (ERBB1), v-erb-b2 erythroblastic leukemia viral oncogene homolog 2 (ERBB2), v-erb-b2 erythroblastic leukemia viral oncogene homolog 3 (ERBB3), v-erb-a erythroblastic leukemia viral oncogene homolog 4 (ERBB4), v-akt murine thymoma viral oncogene homolog 1- mammalian target of rapamycin (AKT-mTOR), protein kinase, AMP-activated, alpha 2 catalytic subunit (AMPK), and autophagy-related signaling, along with transforming growth factor-beta-signaling protein 1 (SMAD), insulin-line growth factor receptor (IGFR), rearranged during transfection proto-oncogene (RET), and activated CDC42-associated kinase (ACK) activation. Investigation of epidermal growth factor receptor (EGFR)-driven signaling identified a unique cohort of tumors with low EGFR protein expression yet high relative levels of phosphorylated EGFR and high EGFR total protein with low relative levels of phosphorylation. Last, mapping analysis of patients with NSCLC with N0 disease revealed a pilot pathway activation signature composed of linked epidermal growth factor receptor family (HER)-AMPK-AKT-mTOR signaling network along with focal adhesion kinase- LIM domain kinase-1 (FAK-LIMK) and janus kinase (JAK)-signal transducers and activators of transcription (STAT) pathways that correlated with short-term survival and aggressive disease. Conclusions Functional protein pathway activation mapping of NSCLC reveals distinct activation subgroups that are underpinned by important therapeutic targets and that patients with early-stage node negative disease and poor prognosis may be identified by activation of defined, biochemically linked protein signaling events. Such findings, if confirmed in larger study sets, could help select and stratify patients for personalized targeted therapies.