Eduardo A. Parra

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The p21Waf1/Cip1 protein (hereafter, p21) and the c‑Jun N-terminal kinase (JNK) are two well-characterized cell modulators that play a crucial role in cell differentiation, senescence and apoptosis. Here, we report that transcription of the p21Waf1/Cip1 and JNK-1 genes is affected by inhibition of the early growth response-1 (Egr-1) in response to a small(More)
Protein phosphatase 4 (PP4) is a protein phosphatase 2A (PP2A)-related, okadaic acid-sensitive, serine/threonine protein phosphatase that shares 65% amino acid identity with PP2A. Numerous studies have shown that protein phosphatase is involved in the regulation of T cell signaling and activation. In this study, we investigated the effect of overexpression(More)
To address elements that might uniquely characterize EGR-1 mediated signaling, the expression of two transcription factors, namely, nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1) were studied. PC-3 and LNCaP prostate carcinoma cell lines were transiently transfected with wild-type Egr-1 expression plasmid (pCMV-Egr-1) and treated with(More)
The specific signaling connections between the mitogen-activated protein kinases (MAPK) such as c-Jun N-terminal kinase (JNK-1) and phosphatases PP4 and M3/6, affecting the family of early nuclear factors, is complex and remains poorly understood. JNK-1 regulates cellular differentiation, apoptosis and stress responsiveness by up-regulating early nuclear(More)
Previous studies have shown that c-Jun-N-terminal kinase-1 (JNK-1) is involved in the transformation of primary fibroblasts and plays a role in tumor cell growth. A number of observations suggest that JNK-1 is a growth promoting factor in prostate cancer cells and blocking its function may induce apoptosis. To test this(More)
The inhibitory effect of a specific small EGR-1 interfering RNA (siRNA) on cell proliferation and the expression of EGR-1 in human prostate carcinoma cell lines PC-3 and LNCaP was investigated. To knockdown Egr-1 expression, a siRNA targeting against Egr-1 was synthesized and transfected into PC-3 and LNCaP cells. The down-regulation of Egr-1 expression at(More)
We have examined the effects of a siRNA targeting the Egr-1, alone or in combination with the breast cancer therapeutic camptothecin (Cpt), in suppressing breast cancer cell survival and anchorage-independent growth in the breast cancer cell lines SK-BR3 and MCF-7. In mammary and lung tumors, as well as most normal tissues, Egr-1 expression is low,(More)
Previous studies suggest that the effects of Egr-1 on tumorigenesis are critically dependent on the levels of Egr-1 and the cellular context. For this reason, we examined the effects of blocking the Egr-1 activity by a short interfering RNA (siRNA) against Egr-1 on the expression of nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) signaling in the(More)