Molecular mechanisms of hemostasis impairment in oncology

Malignant neoplasms are characterized by the presence of the hemostasis system pathology, predisposing cancer patients to thrombohemorrhagic complications. The pathogenesis of cancer-associated coagulopathy is complex and involves a variety of mechanisms. Tumor cells have the ability to activate the host’s hemostasis system, and this phenomenon is controlled by the same oncogenes that are responsible for neoplastic transformation. In addition to predisposing factors to impaired hemostasis from the side of the disease, the anticancer drugs themselves carry risks of developing coagulation disorders. The pathophysiological basis of this kind of disorders caused by chemotherapy is associated with damage to the endothelium, imbalance of coagulation and anticoagulant proteins, platelet dysfunction and their deficiency. In this article, the authors set themselves the goal of generalizing and updating the current knowledge of the molecular mechanisms that cause thrombohemorrhagic risk in cancer.

A Histopathology Model of Astrocytoma

Neoplastic transformation occurs in all glial cell types of the human nervous system, producing a wide variety of clinic-pathological entities and morphological variants. As the molecular events responsible for astrocytoma formation and progression are being clarified, it is becoming possible to correlate these alterations with the specific histopathological and biological features of astrocytoma, anaplastic astrocytoma and glioblastoma multiforme. Diagnosis, treatment, and prognostication in brain stem astrocytoma’s have been hindered by the occurrence in the same site of two distinct pathological entities-fibrillary and pilocytic astrocytoma. The small size of the specimens from this region adds an additional confounding factor in tumor classification. Nevertheless, histological assignment to either of these two prognostically different categories is often possible, especially if the importance of this distinction is recognized. In the face of a nonspecific histological diagnosis, e.g. "low-grade astrocytoma', certain radiographic and clinical features may, in combination with the pathological findings, be useful in tumor subclassification.

Priming, Triggering, Adaptation and Senescence (PTAS): A Hypothesis for a Common Damage Mechanism of Steatohepatitis

Understanding the pathomechanism of steatohepatitis (SH) is hampered by the difficulty of distinguishing between causes and consequences, by the broad spectrum of aetiologies that can produce the phenotype, and by the long time-span during which SH develops, often without clinical symptoms. We propose that SH develops in four phases with transitions: (i) priming lowers stress defence; (ii) triggering leads to acute damage; (iii) adaptation, possibly associated with cellular senescence, mitigates tissue damage, leads to the phenotype, and preserves liver function at a lower level; (iv) finally, senescence prevents neoplastic transformation but favours fibrosis (cirrhosis) and inflammation and further reduction in liver function. Escape from senescence eventually leads to hepatocellular carcinoma. This hypothesis for a pathomechanism of SH is supported by clinical and experimental observations. It allows organizing the various findings to uncover remaining gaps in our knowledge and, finally, to provide possible diagnostic and intervention strategies for each stage of SH development.

BK Polyomavirus Activates HSF1 Stimulating Human Kidney Hek293 Cell Proliferation

Objectives. Some DNA viruses, such as BKPyV, are capable of inducing neoplastic transformation in human tissues through still unclear mechanisms. The goal of this study is to investigate the carcinogenic potential of BK polyomavirus (BKPyV) in human embryonic kidney 293 (Hek293) cells, dissecting the molecular mechanism that determines the neoplastic transformation. Materials and Methods. BKPyV, isolated from urine samples of infected patients, was used to infect monolayers of Hek293 cells. Subsequently, intracellular redox changes, GSH/GSSH concentration by HPLC, and reactive oxygen/nitrogen species (ROS/RNS) production were monitored. Moreover, to understand the signaling pathway underlying the neoplastic transformation, the redox-sensitive HFS1-Hsp27 molecular axis was examined using the flavonoid quercetin and polishort hairpin RNA technologies. Results. The data obtained show that while BKPyV replication is closely linked to the transcription factor p53, the increase in Hek293 cell proliferation is due to the activation of the signaling pathway mediated by HSF1-Hsp27. In fact, its inhibition blocks viral replication and cell growth, respectively. Conclusions. The HSF1-Hsp27 signaling pathway is involved in BKPyV infection and cellular replication and its activation, which could be involved in cell transformation.

Anabolic Steroids-Driven Regulation of Porcine Ovarian Putative Stem Cells Favors the Onset of Their Neoplastic Transformation

Nandrolone (Ndn) and boldenone (Bdn), the synthetic testosterone analogues with strong anabolic effects, despite being recognized as potentially carcinogenic compounds, are commonly abused by athletes and bodybuilders, which includes women, worldwide. This study tested the hypothesis that different doses of Ndn and Bdn can initiate neoplastic transformation of porcine ovarian putative stem cells (poPSCs). Immunomagnetically isolated poPSCs were expanded ex vivo in the presence of Ndn or Bdn, for 7 and 14 days. Results show that pharmacological doses of both Ndn and Bdn, already after 7 days of poPSCs culture, caused a significant increase of selected, stemness-related markers of cancer cells: CD44 and CD133. Notably, Ndn also negatively affected poPSCs growth not only by suppressing their proliferation and mitochondrial respiration but also by inducing apoptosis. This observation shows, for the first time, that chronic exposure to Ndn or Bdn represents a precondition that might enhance risk of poPSCs neoplastic transformation. These studies carried out to accomplish detailed molecular characterization of the ex vivo expanded poPSCs and their potentially cancerous derivatives (PCDs) might be helpful to determine their suitability as nuclear donor cells (NDCs) for further investigations focused on cloning by somatic cell nuclear transfer (SCNT). Such investigations might also be indispensable to estimate the capabilities of nuclear genomes inherited from poPSCs and their PCDs to be epigenetically reprogrammed (dedifferentiated) in cloned pig embryos generated by SCNT. This might open up new possibilities for biomedical research aimed at more comprehensively recognizing genetic and epigenetic mechanisms underlying not only tumorigenesis but also reversal/retardation of pro-tumorigenic intracellular events.

PROBLEMATIC ISSUES IN THE EVALUATION OF MOLECULAR CHARACTERISTICS AND POTENTIAL NEOPLASTIC TRANSFORMATION OF CERVICAL METAPLASIA

Metaplasia represents the replacement of one differentiated cell type with another differentiated cell type, which is frequently seen in uterine cervix, particularly in endocervical epithelium. There are many different types of metaplasia in endocervix. It is suggested that metaplasia represents the fertile soil for the development of neoplasia. However, which cases of metaplasia transform into neoplasia, which type of metaplasia is more realted to neoplastic transformation or if there are some molecular markers which can predict the potential of neoplastic transformation, are nowadays less known. Current review represents the critical discussion of the available literature with regards to the evaluation of molecular markers and the potential of neoplastic transformation in cervical metaplasia.

Fine-tuned repression of Drp1 driven mitochondrial fission primes a 'stem/progenitor-like state' to support neoplastic transformation

Gene knockout of the master regulator of mitochondrial fission, Drp1, prevents neoplastic transformation. Also, mitochondrial fission and its opposing process of mitochondrial fusion are emerging as crucial regulators of stemness. Intriguingly, stem/progenitor cells maintaining repressed mitochondrial fission are primed for self-renewal and proliferation. Using our newly derived carcinogen transformed human cell model we demonstrate that fine-tuned Drp1 repression primes a slow cycling 'stem/progenitor-like state', which is characterized by small networks of fused mitochondria and a gene-expression profile with elevated functional stem/progenitor markers (Krt15, Sox2 etc) and their regulators (Cyclin E). Fine tuning Drp1 protein by reducing its activating phosphorylation sustains the neoplastic stem cell markers. Whereas, fine-tuned reduction of Drp1 protein maintains the characteristic mitochondrial shape and gene-expression of the primed 'stem/progenitor-like state' to accelerate neoplastic transformation, and more complete reduction of Drp1 protein prevents it. Therefore, our data highlights a 'goldilocks'; level of Drp1 repression supporting stem/progenitor state dependent neoplastic transformation.