Aspirin and its pleiotropic application

Aspirin (acetylsalicylic acid), the oldest synthetic drug, was originally used as an anti-inflammatory medication. Being an irreversible inhibitor of COX (prostaglandin-endoperoxide synthase) enzymes that produce precursors for prostaglandins and thromboxanes, it has gradually found several other applications. Sometimes these applications are unrelated to its original purpose for example its use as an anticoagulant. Applications such as these have opened opportunities for new treatments. In this case, it has been tested in patients with cardiovascular disease to reduce the risk of myocardial infarct. Its function as an anticoagulant has also been explored in the prophylaxis and treatment of pre-eclampsia, where due to its anti-inflammatory properties, aspirin intake may be used to reduce the risk of colorectal cancer. It is important to always consider both the risks and benefits of aspirin's application. This is especially important for proposed use in the prevention and treatment of neurologic ailments like Alzheimer's disease, or in the prophylaxis of myocardial infarct. In such cases, the decision if aspirin should be applied, and at what dose may be guided by specific molecular markers. In this revived paper, the pleiotropic application of aspirin is summarized.

BRCA1 promoter methylation in peripheral blood is associated with the risk of triple-negative breast cancer

Methylation of the promoter of the BRCA1 gene in DNA derived from peripheral blood cells is a possible risk factor for breast cancer. It is not clear if this association is restricted to certain types of breast cancer or is a general phenomenon. We evaluated BRCA1 methylation status in peripheral blood cells from 942 breast cancer patients and from 500 controls. We also assessed methylation status in 262 paraffin-embedded breast cancer tissues. Methylation status was assessed using methylation-sensitive high-resolution melting and was categorized as positive or negative. BRCA1 methylation in peripheral blood cells was strongly associated with the risk of triple-negative breast cancer (TNBC) (odds ratio [OR] 4.70; 95% confidence interval [CI]: 3.13-7.07; p < 0.001), but not of estrogen-receptor positive breast cancer (OR 0.80; 95% CI: 0.46-1.42; p = 0.46). Methylation was also overrepresented among patients with high-grade cancers (OR 4.53; 95% CI: 2.91-7.05; p < 0.001) and medullary cancers (OR 3.08; 95% CI: 1.38-6.88; p = 0.006). Moreover, we detected a significant concordance of BRCA1 promoter methylation in peripheral blood and paired tumor tissue (p < 0.001). We found that BRCA1 promoter methylation in peripheral blood cells is associated with approximately five times greater risk of TNBC. We propose that BRCA1 methylation in blood-derived DNA could be a novel biomarker of increased breast cancer susceptibility, in particular for triple-negative tumors.

Psoriasis Treatment Changes the Expression Profile of Selected Caspases and their Regulatory MicroRNAs

BACKGROUND/AIMS

Psoriasis, an autoimmune diseases of the skin, characterized by patches of abnormal/inflammed skin, although not usually life-threatening, it causes severe discomfort, esthetic impairments, and may lead to impaired social functions and social withdrawal. Besides UV-phototherapy, various anti-inflammatory treatments are applied, depending on the severity of symptoms. In 2008, adalimumab (fully humanized human anti-TNF antibody) was launched for the treatment of psoriasis. In the quest to better understand the pathomechanism of adalimumab's therapeutic effects, and the acquired resistance to the drug, we have investigated how its administration affect the regulation of the expression of selected caspases, including those activated by inflammosome.

METHODS

The research was initially carried out on normal human dermal fibroblasts (NHDF) treated with adalimumab for 2, 8 and 24 hours in vitro. Then, expression profile of genes encoding caspases and their regulatory micro-RNAs was determined with the use of oligonucleotide microarray. The validation of the microarray results was carried out by qRT-PCR. The in vitro study was followed by ex-vivo investigation of adalimumab's effects on the expression of caspase-6 in blood of the psoriatic patients. The samples were collected before, and 2 hours after adalimumab's administration and the analysis was determined by qRT-PCR.

RESULTS

The result of the analysis indicated that introduction of adalimumab to the NHDF culture resulted in the change of the transcription activity of genes encoding caspases and genes encoding miRNAs. The analysis revealed 5 different miRNA molecules regulating the expression of: CASP2, CASP3 and CASP6. There were no statistically significant differences in the expression of gene encoding caspase-6 in the patients' blood before and 2 hours after the anti-TNF drug administration.

CONCLUSION

We have found that adalimumab administration affects caspases expression, thus they may be used as molecular markers for monitoring the therapy with the use of an anti-TNF drugs, including adalimumab. It is likely that the mechanisms responsible for changed expression profiles of genes encoding caspase-2,-3, and -6, may be caused by the upregulation of the respective microRNA molecules. Increased expression of genes encoding specific caspases may induce inflammatory processes, as well as trigger apoptosis. Furthermore, the proapoptotic activity of caspases may be enhanced by miRNA molecules, which exhibit proapoptotic function. The overexpression of such miRNAs was observed in our study.

Pathological complete response after cisplatin neoadjuvant therapy is associated with the downregulation of DNA repair genes in BRCA1-associated triple-negative breast cancers

Pathologic complete response (pCR) after neoadjuvant chemotherapy is considered a suitable surrogate marker of treatment efficacy in patients with triple-negative breast cancers (TNBCs). However, the molecular mechanisms underlying pCR as a result of such treatment remain obscure. Using real-time PCR arrays we compared the expression levels of 120 genes involved in the main mechanisms of DNA repair in 43 pretreatment biopsies of BRCA1-associated TNBCs exhibiting pCR and no pathological complete response (non-pCR) after neoadjuvant chemotherapy with cisplatin. Altogether, 25 genes were significantly differentially expressed between tumors exhibiting pCR and non-pCR, and these genes were downregulated in the pCR group compared to the non-pCR group. A difference in expression level greater than 1.5-fold was detected for nine genes: MGMT, ERCC4, FANCB, UBA1, XRCC5, XPA, XPC, PARP3, and RPA1. The non-homologous end joining and nucleotide excision repair pathways of DNA repair showed the most significant relevance. Expression profile of DNA repair genes associated with pCR was different in the node-positive (20 genes with fold change >1.5) and node-negative (only 3 genes) subgroups. Although BRCA1 germline mutations are the principal defects in BRCA1-associated TNBC, our results indicate that the additional downregulation of other genes engaged in major pathways of DNA repair may play a decisive role in the pathological response of these tumors to cisplatin neoadjuvant chemotherapy. The results suggest that patients with node-positive BRCA1-associated TNBCs that do not exhibit pCR after cisplatin neoadjuvant chemotherapy may be candidates for subsequent therapy with PARP inhibitors, whereas UBA1 may be a potential therapeutic target in node-negative subgroup.

Colorectal cancers differ in respect of PARP-1 protein expression

Recent findings raise the possibility of PARP inhibitor therapy in colorectal cancers (CRCs). However, the extent of PARP-1 protein expression in clinical specimens of CRC is not known. Using immunohistochemistry we assessed PARP-1 protein expression in tissue microarrays of 151 CRCs and its association with the patient's age, sex, Astler-Coller stage, grade and site of the tumor. High PARP nuclear immunoreactivity was found in 68.2% (103/151) of all cases. In turn, 31.8% (48/151) of tumors showed low PARP expression, including 9 (6%) PARP-1 negative CRCs. There was a significant association of PARP-1 expression with the site of CRC and Astler-Coller stage. A high PARP expression was noted in 79.1% of colon vs. 53.9% of rectal tumors (p = 0.001). The mean PARP-1 score was 1.27 times higher in colon vs. rectal cancers (p = 0.009) and it was higher in stage B2 vs. stage C of CRCs (p = 0.018). In conclusion, the level of PARP-1 protein nuclear expression is associated with the tumor site and heterogeneous across clinical specimens of CRC, with the majority of CRCs expressing a high level but minority - low or no PARP-1 expression. These findings may have a clinical significance because the assessment of PARP-1 expression in tumor samples may improve selection of patients with CRC for PARP inhibitor therapy.

Potassium channels in barley: cloning, functional characterization and expression analyses in relation to leaf growth and development

It is not known how the uptake and retention of the key osmolyte K(+) in cells are mediated in growing leaf tissue. In the present study on the growing leaf 3 of barley, we have cloned the full-length coding sequence of three genes which encode putative K(+) channels (HvAKT1, HvAKT2, HvKCO1/HvTPK1), and of one gene which encodes a putative K(+) transporter (HvHAK4). The functionality of the gene products of HvAKT1 and HvAKT2 was tested through expression in Xenopus laevis oocytes. Both are inward-rectifying K(+) channels which are inhibited by Cs(+). Function of HvAKT1 in oocytes requires co-expression of a calcineurin-interacting protein kinase (AtCIPK23) and a calcineurin B-like protein (AtCBL9) from Arabidopsis, showing cross-species complementation of function. In planta, HvAKT1 is expressed primarily in roots, but is also expressed in leaf tissue. HvAKT2 is expressed particularly in leaf tissue, and HvHAK4 is expressed particularly in growing leaf tissue. Within leaves, HvAKT1 and HvAKT2 are expressed predominantly in mesophyll. Expression of genes changes little in response to low external K(+) or salinity, despite major changes in K(+) concentrations and osmolality of cells. Possible contributions of HvAKT1, HvAKT2, HvKCO1 and HvHAK4 to regulation of K(+) relations of growing barley leaf cells are discussed.