Ryszard Maciejewski

Diagnostic and prognostic significance of miRNA signatures in tissues and plasma of endometrioid endometrial carcinoma patients

The aim of our study was to define tissue and plasma miRNA signatures, which could potentially serve as diagnostic and prognostic markers in endometrioid endometrial cancer (EEC) and to investigate miRNA profiles in regard to clinicopathological characteristics. Tissue and plasma samples were collected from 122 women (77 EEC and 45 controls). Expression profiling of 866 human miRNAs and 89 human viral miRNAs was performed in 24 samples and was followed by qPCR validation in 104 patients. Expression of 16 miRNAs was analyzed in 48 plasma samples. Microarray study revealed regulation of 21 miRNAs in EEC tissues comparing to normal endometrium. Altered expression of 17 miRNAs was confirmed by qPCR performed in 104 tissue samples. Seven miRNAs were upregulated and two were downregulated in EEC plasma samples. Expression of a number of miRNAs was associated with International Federation of Gynecology and Obstetrics stage, grade, relapse and nodal metastases. Two miRNA signatures: miR‐92a/miR‐410 and miR‐92a/miR‐205/miR‐410 classified tumor tissues with higher accuracy in comparison to single miRNAs (AUC: 0.977, 95% CI: 0.927–0.996 and 0.984, 95% CI: 0.938–0.999, respectively). miRNA signature composed of miR‐205 and miR‐200a predicted relapse with AUC of 0.854 (95% CI: 0.691–0.951). Tissue miRNA signatures were independent prognostic markers of overall (miR‐1228/miR‐200c/miR‐429, HR: 2.98) and progression‐free survival (miR‐1228/miR‐429, HR: 2.453). Plasma miRNA signatures: miR‐9/miR‐1228 and miR‐9/miR‐92a, classified EEC plasma samples with high accuracy yielding AUCs of 0.909 (95% CI: 0.789–973) and 0.913 (95% CI: 0.794–0.976), respectively. We conclude that miRNA signatures hold a great promise to become noninvasive biomarkers for early EEC detection and prognosis.

Deregulation of miR-100, miR-99a and miR-199b in tissues and plasma coexists with increased expression of mTOR kinase in endometrioid endometrial carcinoma

BackgroundAlterations of mTOR gene expression have been implicated in the pathogenesis of endometrioid endometrial cancer however only few studies explored the cause of increased mTOR activation in this malignancy. miRNAs are small, noncoding RNAs, which were proven to regulated gene expression at the posttranscriptional level. The study aimed to explore deregulation of miRNAs targeting mTOR kinase (miR-99a, miR-100 and miR-199b) as a possible cause of its altered expression in EEC tissues. In addition expression of the three miRNAs was investigated in plasma of EEC patients and was assessed in terms of diagnostic and prognostic utility.MethodsWe investigated expression of mTOR kinase transcripts in 46 fresh tissue samples. Expression of miR-99a, miR-100 and miR-199b was investigated in the same group of fresh samples, and in additional 58 FFPE sections as well as in 48 plasma samples using qPCR. Relative quantification was performed using experimentally validated endogenous controls.ResultsmTOR kinase expression was increased in EEC tissues and was accompanied by decreased expression of all three miRNAs. Down-regulation of the investigated miRNAs was discovered in plasma of EEC patients and miRNA signatures classified EEC tissues (miR-99a/miR-100/miR-199b) and plasma (miR-99a/miR-199b) samples with higher accuracy in comparison to single miRNAs. We also revealed that miR-100 was an independent prognostic marker of overall survival.ConclusionsWe conclude that increased expression of mTOR kinase coexists with down-regulation of its targeting miRNAs, which could suggest a new mechanism of mTOR pathway alterations in EEC. In addition, our findings implicate that miRNA signatures can be considered promising biomarkers for early detection and prognosis of endometrioid endometrial carcinoma.

Sporadic Alzheimer’s Disease Begins as Episodes of Brain Ischemia and Ischemically Dysregulated Alzheimer’s Disease Genes

The study of sporadic Alzheimer’s disease etiology, now more than ever, needs an infusion of new concepts. Despite ongoing interest in Alzheimer’s disease, the basis of this entity is not yet clear. At present, the best-established and accepted “culprit” in Alzheimer’s disease pathology by most scientists is the amyloid, as the main molecular factor responsible for neurodegeneration in this disease. Abnormal upregulation of amyloid production or a disturbed clearance mechanism may lead to pathological accumulation of amyloid in brain according to the “amyloid hypothesis.” We will critically review these observations and highlight inconsistencies between the predictions of the “amyloid hypothesis” and the published data. There is still controversy over the role of amyloid in the pathological process. A question arises whether amyloid is responsible for the neurodegeneration or if it accumulates because of the neurodegeneration. Recent evidence suggests that the pathophysiology and neuropathology of Alzheimer’s disease comprises more than amyloid accumulation, tau protein pathology and finally brain atrophy with dementia. Nowadays, a handful of researchers share a newly emerged view that the ischemic episodes of brain best describe the pathogenic cascade, which eventually leads to neuronal loss, especially in hippocampus, with amyloid accumulation, tau protein pathology and irreversible dementia of Alzheimer type. The most persuasive evidences come from investigations of ischemically damaged brains of patients and from experimental ischemic brain studies that mimic Alzheimer-type dementia. This review attempts to depict what we know and do not know about the triggering factor of the Alzheimer’s disease, focusing on the possibility that the initial pathological trigger involves ischemic episodes and ischemia-induced gene dysregulation. The resulting brain ischemia dysregulates additionally expression of amyloid precursor protein and amyloid-processing enzyme genes that, in addition, ultimately compromise brain functions, leading over time to the complex alterations that characterize advanced sporadic Alzheimer’s disease. The identification of the genes involved in Alzheimer’s disease induced by ischemia will enable to further define the events leading to sporadic Alzheimer’s disease-related abnormalities. Additionally, knowledge gained from the above investigations should facilitate the elaboration of the effective treatment and/or prevention of Alzheimer’s disease.

Brain Ischemia Activates β- and γ-Secretase Cleavage of Amyloid Precursor Protein: Significance in Sporadic Alzheimer’s Disease

Amyloid precursor protein cleavage through β- and γ-secretases produces β-amyloid peptide, which is believed to be responsible for death of neurons and dementia in Alzheimer’s disease. Levels of β- and γ-secretase are increased in sensitive areas of the Alzheimer’s disease brain, but the mechanism of this process is unknown. In this review, we prove that brain ischemia generates expression and activity of both β- and γ-secretases. These secretases are induced in association with oxidative stress following brain ischemia. Data suggest that ischemia promotes overproduction and aggregation of β-amyloid peptide in brain, which is toxic for ischemic neuronal cells. In our review, we demonstrated the role of brain ischemia as a molecular link between the β- and the γ-secretase activities and provided a molecular explanation of the possible neuropathogenesis of sporadic Alzheimer’s disease.

Selection and validation of endogenous controls for microRNA expression studies in endometrioid endometrial cancer tissues.

OBJECTIVES microRNAs comprise a family of small, non-coding RNAs, which regulate gene expression at the posttranscriptional level. Multiple studies implicated important roles of microRNAs in various malignancies including endometrioid endometrial carcinoma (EEC). qPCR is widely used in the studies investigating microRNA expression. Relative quantification of microRNA expression requires proper normalization methods and endogenous controls are widely used for this purpose. The aim of this study was experimental identification of stable endogenous controls for normalization of microRNA qPCR expression studies in EEC. METHODS Expression of twelve candidate endogenous controls (miR-16, miR-26b, miR-92a, RNU44, RNU48, U75, U54, U6, U49, RNU6B, RNU38B, U18A) was investigated in tissue samples obtained from 45 patients (30 EEC, 15 normal endometrium) using qPCR. Stability of candidate endogenous controls was evaluated using NormFinder, geNorm, BestKeeper and equivalency test. The results were then validated using larger group of samples. RESULTS RNU48, U75 and RNU44 were identified as stably and equivalently expressed between malignant and normal tissues. Both NormFinder and geNorm indicated that those three snRNAs were optimal for qPCR data normalization in EEC tissues. CONCLUSIONS In conclusion, we suggest that average expression of those snoRNAs could be used as a reliable endogenous control in microRNA qPCR studies in endometrioid endometrial cancer. In addition to identifying suitable endogenous controls in EEC, our study presents an appropriate strategy for validation of candidate reference genes for any microRNA qPCR study.

Major regulators of microRNAs biogenesis Dicer and Drosha are down-regulated in endometrial cancer

Alterations in microRNAs expression have been proposed to play role in endometrial cancer pathogenesis. Dicer and Drosha are main regulators of microRNA biogenesis and deregulation of their expression has been indicated as a possible cause of microRNAs alterations observed in various cancers. The objective of this study was to investigate Dicer and Drosha genes expression in endometrial cancer and to analyze the impact of clinicopathological characteristics on their expression. Fresh tissue samples were collected from 44 patients (26 endometroid endometrial carcinoma and 18 controls). Clinical and pathological data were acquired from medical documentation. Dicer and Drosha genes expressions were assessed by qRT-PCR using validated reference genes. Dicer and Drosha expression levels were significantly lower in endometrial cancer samples comparing to controls. Dicer was down-regulated by the factor of 1.54 (p = 0.009) and Drosha gene mean expression value was 1.4 times lower in endometrial cancer group versus control group (p = 0.008). Down-regulation of Dicer significantly correlated with decreased expression of Drosha (coefficient value 0.75). Decreased expression of Drosha correlated with higher histological grade and was influenced by BMI. Lower Dicer expression was found in nulli- and uniparous females comparing to multiparous individuals (p = 0.002). Neither the FIGO stage nor the menstrual status had significant influence on the expression of studied genes. This study revealed for the first time that expression alterations of main regulators of microRNAs biogenesis are present in endometrial cancer tissue and could be potentially responsible for altered microRNAs profiles observed in this malignancy.

The COX-2 promoter polymorphism -765 G > C is associated with early-onset, conventional and stump gastric cancers

COX-2 overexpression is known to be an important mechanism in gastric carcinogenesis. Previously we have found that early-onset gastric cancer has a unique COX-2 low-expressing phenotype that differs significantly from that of the frequent overexpression seen in conventional gastric cancers. To investigate whether the COX-2 –765 G>C promoter polymorphism (known to lead to a reduction of COX-2 promoter activity in the colon) may explain this difference in expression, we carried out single-nucleotide polymorphism (SNP) analysis of 241 gastric cancers, including early-onset gastric cancer, conventional gastric cancers and gastric stump cancers, as well as in 100 control patients, using real-time PCR and sequence analysis, and correlated these findings with COX-2 expression using immunohistochemistry. We found that the C allele was present in 30% of early-onset gastric cancers, 24% of conventional gastric cancer, 23% of stump cancers, in contrast to 41% in the control group. There was a statistically significant difference in the presence of the C allele in patients with gastric cancer compared with the control group (P=0.007), with the C allele being associated with protection against gastric cancer. However, there was no significant difference between the early-onset, conventional and stump gastric cancer groups. Interestingly, there was no correlation between the presence of the C allele and a difference in COX-2 expression. In summary, we show that the COX-2 –765 G allele promoter polymorphism is significantly associated with gastric cancer when compared with the normal control group, but does not appear to be related directly to COX-2 expression pattern in gastric cancer. Although early-onset gastric cancers appear to have a unique COX-2 expression pattern when compared with conventional gastric cancer, the exact mechanism by which this occurs is yet to be elucidated.

Cytokine response in the postoperative period after surgical treatment of benign adnexal masses : comparison between laparoscopy and laparotomy

BackgroundCytokines are the main mediators of the inflammation and the response to trauma. The purpose of the present study was the comparative assessment in sera of patients with benign adnexal masses treated by laparoscopy or laparotomy of the following proinflammatory and anti-inflammatory cytokines: interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor-alpha (TNF-α), and IL-10 in the early postoperative period.MethodsA total of 40 patients with benign adnexal masses were studied; 25 of whom underwent laparoscopy and 15, laparotomy. Blood serum concentration of IL-1β, IL-6, IL-8, TNF-α, and IL-10 were measured by commercially available ELISA assays before and 4 h, 24 h, and 48 h after the operation.ResultsConcentrations of IL-6 were significantly increased in both groups at 4 h, 24 h, and 48 h after the surgery; levels of IL-10 showed a significant increase 4 h and 24 h after the operation; an increase in IL-1β levels was observed only after laparotomy; no significant variations were observed in serum levels of IL-8; the postoperative increase of IL-1β, IL-6, and IL-10 levels was more pronounced in patients undergoing laparotomy than in those treated laparoscopically; length of the surgical procedure, amount of CO2 used, tumor diameter, age, and body mass index (BMI) of the patients did not influence the postoperative patterns of the studied cytokines.ConclusionsSystemic cytokine response after operations for benign adnexal masses depends on the degree of the surgical trauma, and is less pronounced in patients undergoing laparoscopy.

Retigabine: the newer potential antiepileptic drug

Retigabine represents an antiepileptic drug possessing a completely different mechanism of action when compared to the existing classical and newer antiepileptic drugs. In the therapeutic range, retigabine enhances potassium currents, very likely via destabilization of a closed conformation or stabilization of the open conformation of the potassium Kv7.2-7.3 channels. There are also data indicating that this drug may be a GABA enhancer. Kainate-induced status epilepticus in rats resulted in massive apoptosis in the pyriform cortex and hippocampal area - retigabine inhibited neurodegeneration only in the former brain structure. The metabolism of retigabine has nothing to do with cytochrome P450 enzymes and the drug undergoes glucuronidation and acetylation. Randomized, placebo-controlled multicenter studies have shown that retigabine produced a considerable improvement as an add-on drug in patients with partial drug-resistant epilepsy. The most prominent adverse effects due to retigabine combined with the existing antiepileptic treatment were dizziness, somnolence and fatigue. The preclinical data indicate that this antiepileptic drug may possibly be applied in patients with neuropathic pain and affective disorders. Initial clinical data suggest that retigabine may be also effective in Alzheimers disease or stroke.

MicroRNAs and their role in gynecological tumors

There have been only few events in the history of molecular biology that could be compared to the discovery of microRNAs and their role in cell physiology and pathology. MicroRNAs are small, single‐stranded, noncoding RNAs composed of 19–25 nucleotides (∼22 nt), which have been proven to regulate gene expression at the posttranscriptional level. The regulatory function of microRNAs was demonstrated in normal and diseased conditions. In particular, it has been linked to cell cycle regulation, cell proliferation and differentiation, inflammatory response, and apoptosis. Altered expression profiles of microRNA have been observed in many pathologies, including diabetes, rheumatoid arthritis, and several cancers. To date, more than 700 human microRNAs have been identified and in silico‐based analyses estimate at least 500 more to be identified. The purpose of this review is to present the current perspective on microRNAs structure and biogenesis as well as their contribution to the etiopathogenesis of gynecological tumors. We discuss results of the recent publications that indicate possibilities of microRNAs use as novel markers for tumors screening, early diagnosis, and treatment monitoring. The possible utilization of microRNAs as prognostic factors and specific therapy targets is also reviewed.