Synthetic Derivatives of Natural ent-Kaurane Atractyligenin Disclose Anticancer Properties in Colon Cancer Cells, Triggering Apoptotic Cell Demise

The antitumor activity of different ent-kaurane diterpenes has been extensively studied. Several investigations have demonstrated the excellent antitumor activity of synthetic derivatives of the diterpene atractyligenin. In this research, a series of new synthetic amides and their 15,19-di-oxo analogues obtained from atractyligenin by modifying the C-2, C-15, and C-19 positions were designed in order to dispose of a set of derivatives with different substitutions at the amidic nitrogen. Using different concentrations of the obtained compounds (10-300 μM) a reduction in cell viability of HCT116 colon cancer cells was observed at 48 h of treatment. All the di-oxidized compounds were more effective than their alcoholic precursors. The di-oxidized compounds had already reduced the viability of two colon cancer cells (HCT116 and Caco-2) at 24 h when used at low doses (2.5-15 μM), while they turned out to be poorly effective in differentiated Caco-2 cells, a model of polarized enterocytes. The data reported here provide evidence that di-oxidized compounds induced apoptotic cell death, as demonstrated by the appearance of condensed and fragmented DNA in treated cells, as well as the activation of caspase-3 and fragmentation of its target PARP-1.

Hesperetin may alleviate the development of doxorubicin-induced pulmonary toxicity by decreasing oxidative stress and apoptosis in male rats

Doxorubicin (DOX) is one of the most widely used chemotherapeutic agents. However, it causes pulmonary toxicity which decreases its clinical use in human cancer therapy. The present study was undertaken to obtain an insight into the potential protective effect of hesperetin (HES) against doxorubicin-induced pulmonary toxicity in rats. The animals were divided into 4 groups with 7 rats per group. The experimental treatments were as follows: Control, DOX, DOX + HES, and HES groups. DOX was administered at the dosage of 15 mg/kg i.p for a single dose. HES was administered at the dosage of 50 mg/kg by oral gavage every other day. After 28 days, biochemical parameters, oxidative stress status, histopathological changes, apoptosis-related genes and apoptotic index (AI) were examined of lung tissue. Histopathological changes, Poly [ADP-ribose] polymerase 1 (PARP-1), Caspase-3 (Casp3), Cytochrome c (Cytc), apoptosis-related genes, and AI significantly increased in the DOX group relative to the control group. Malondialdehyde (MDA) significantly increased, while superoxide dismutase (SOD) and glutathione peroxidase (GPx) decreased in the DOX group relative to the control group. However, histopathological findings, MDA, AI, and PAPR1, Casp3 protein expression, mRNA expression of Cytc significantly decreased, while SOD, GPx increased in the DOX + HES group relative to the DOX group. These results attested HES might be a potential agent for the treatment of DOX-induced pulmonary toxicity.

Role of chromatin assembly factor-1/p60 and poly [ADP-ribose] polymerase 1 in mycosis fungoides

Mycosis fungoides (MF) represents the most common type of cutaneous lymphoma. In the majority of patients, the disease has a slow evolution and a protracted course; however, a subset of patients shows poor oncologic outcomes. Unfortunately, there are no reliable prognostic markers for MF, and the currently available treatments are only effective in a minority of patients. This study aimed to evaluate the expression and clinical significance of PARP-1 and CAF-1/p60 in MF. Sixty-four MF representatives of the different stages of disease were assessed by immunohistochemistry for PARP-1 and CAF-1/p60. The association of PARP-1 and CAF-1/p60 with the MF stage and outcome was assessed by using Fisher’s exact test and Kaplan-Meier survival analysis with the Log-rank test; a p value < 0.05 was considered significant. PARP-1 was overexpressed in 57.9% of MF and was significantly associated with a MF stage > II (p = 0.034) but not with the risk of death (p = 0.237). CAF-1/p60 was overexpressed in 26.8% of MF and was significantly associated with decreased overall survival (p < 0.001) but not with the MF stage (p = 1). A significant association was found between PARP-1 overexpression and CAF-1/p60 overexpression (p = 0.0025). Simultaneous overexpression of PARP-1 and CAF-1/p60 was significantly associated with decreased overall survival (p < 0.001), although less strongly than CAF-1/p60 alone (χ² = 14.916 vs 21.729, respectively). In MF, PARP-1 is overexpressed in advanced stages, while CAF-1/p60 is overexpressed in the cases with shorter overall survival, appearing as a significant prognostic marker. A role for PARP-1 inhibitors and anti-CAF-1/p60 targeted therapy may be reasonably hypothesized in MF.

Regulation of fibrillin-1 gene expression by Sp1

Mutations in the fibrillin-1 gene (FBN1) cause Marfan Syndrome (MFS), a hereditary disorder of connective tissue. The transcription of FBN1 has been reported to be driven by a short ultraconserved region (SUPR) in the 5' untranslated exon A of FBN1, but the nature of other factors involved in FBN1 gene regulation has not been clarified. In this study, we characterized the transcription factors involved in FBN1 gene regulation. The results show that Sp1 protein binds to two putative binding sites in the promoter of FBN1. Overexpression of Sp1 resulted in a significant increase in both promoter activity and FBN1 mRNA level in HEK 293 cells, whereas inhibition or knockdown of Sp1 decreased FBN1 gene expression. In addition, we found that Poly [ADP-ribose] polymerase 1 (PARP1) binds to the palindromic sequence TCTCGCGAGA in the ultraconserved region of the FBN1 promoter and that the regulation of FBN1 expression by PARP1 is dependent on Sp1. These results indicate that both Sp1 and PARP1 contribute to FBN1 gene expression. These observations add to our understanding of the transcriptional regulation of FBN1 gene expression.