TUNAR lncRNA Encodes a Microprotein that Regulates Neural Differentiation and Neurite Formation by Modulating Calcium Dynamics

Long noncoding RNAs (lncRNAs) are regulatory molecules which have been traditionally considered as “non-coding”. Strikingly, recent evidence has demonstrated that many non-coding regions, including lncRNAs, do in fact contain small-open reading frames that code for small proteins that have been called microproteins. Only a few of them have been characterized so far, but they display key functions in a wide variety of cellular processes. Here, we show that TUNAR lncRNA encodes an evolutionarily conserved microprotein expressed in the nervous system that we have named pTUNAR. pTUNAR deficiency in mouse embryonic stem cells improves their differentiation potential towards neural lineage both in vitro and in vivo. Conversely, pTUNAR overexpression impairs neuronal differentiation by reduced neurite formation in different model systems. At the subcellular level, pTUNAR is a transmembrane protein that localizes in the endoplasmic reticulum and interacts with the calcium transporter SERCA2. pTUNAR overexpression reduces cytoplasmatic calcium, consistent with a possible role of pTUNAR as an activator of SERCA2. Altogether, our results suggest that our newly discovered microprotein has an important role in neural differentiation and neurite formation through the regulation of intracellular calcium. From a more general point of view, our results provide a proof of concept of the role of lncRNAs-encoded microproteins in neural differentiation.

Blockade of EIF5A hypusination limits colorectal cancer growth by inhibiting MYC elongation

Eukaryotic Translation Initiation Factor 5A (EIF5A) is a translation factor regulated by hypusination, a unique posttranslational modification catalyzed by deoxyhypusine synthetase (DHPS) and deoxyhypusine hydroxylase (DOHH) starting from the polyamine spermidine. Emerging data are showing that hypusinated EIF5A regulates key cellular processes such as autophagy, senescence, polyamine homeostasis, energy metabolism, and plays a role in cancer. However, the effects of EIF5A inhibition in preclinical cancer models, the mechanism of action, and specific translational targets are still poorly understood. We show here that hypusinated EIF5A promotes growth of colorectal cancer (CRC) cells by directly regulating MYC biosynthesis at specific pausing motifs. Inhibition of EIF5A hypusination with the DHPS inhibitor GC7 or through lentiviral-mediated knockdown of DHPS or EIF5A reduces the growth of various CRC cells. Multiplex gene expression analysis reveals that inhibition of hypusination impairs the expression of transcripts regulated by MYC, suggesting the involvement of this oncogene in the observed effect. Indeed, we demonstrate that EIF5A regulates MYC elongation without affecting its mRNA content or protein stability, by alleviating ribosome stalling at five distinct pausing motifs in MYC CDS. Of note, we show that blockade of the hypusination axis elicits a remarkable growth inhibitory effect in preclinical models of CRC and significantly reduces the size of polyps in APCMin/+ mice, a model of human familial adenomatous polyposis (FAP). Together, these data illustrate an unprecedented mechanism, whereby the tumor-promoting properties of hypusinated EIF5A are linked to its ability to regulate MYC elongation and provide a rationale for the use of DHPS/EIF5A inhibitors in CRC therapy.

rhVEGF and Experimental Rat Skin Flaps: Systemic or Local Administration and Morphological Characteristics

Skin flap survival is a significant problem in skin surgery; in particular, inadequate arterial or venous blood supply results in necrosis of the distalmost portion. The aim of this study was to evaluate the ability of Vascular Endothelial Growth Factor (VEGF) of modifying the morphological features of skin flaps. Bilateral epigastric skin flaps were raised in 16 Wistar male rats. The epigastric artery and vein of the left flaps were clamped and then injected with rhVEGF (8 rats) or saline (8 rats). The right flaps were not clamped and received rhVEGF or saline systemically. The rats were euthanized on the seventh day and flap skin samples collected. Tissue fragments were subject to immunohistochemical (rhVEGF, VEGFr, VIII factor, CD34 antibodies), ultrastructural and morphostructural investigations. The results showed that rhVEGF improved the condition of flaps and that systemic administration was effective in promoting the development of an adequate vascular network.

Combined use of WEB2170 and HBO therapy can reduce ischemia and reperfusion injury to the skeletal muscle in a rabbit model

Ischemia/reperfusion injury is regarded as the main cause of failure in revascularization of limbs and transfer of free flaps in the so called nonreflow phenomenon. This type of damage is caused by the production of free radicals, above all, of neutrophils that release great quantities of extracellular superoxide through the action of a membrane enzyme. In our study we used 40 white rabbits. Rabbit rectus femoris muscle is perfused by a single artery and vein and is therefore a valuable model for study of ischemia-induced reperfusion injury of skeletal muscle. The objective of this study was to individualize a valid method of protection for the muscle from damage by ischemia-induced reperfusion injury. We have tested the effectiveness of WEB2170, a PAF antagonist, of hyperbaric oxygen therapy one (HBO), and of combined employment of WEB2170 and HBO. The results show that both PAF and HBO play important protective roles against damage from ischemia/reperfusion injury, and that the combined employment of both therapies has a synergistic effect. We propose therefore a new therapeutic protocol for the prevention of damage resulting from ischemia/reperfusion injury with the simultaneous employment of this PAF and HBO.

Erythropoietin receptor expression in canine mammary tumor: an immunohistochemical study

Erythropoietin (EPO) is a cytokine primarily involved in the regulation of the erythropoiesis. Recently, it has been demonstrated that EPO and its receptor (EPOR) are expressed in several neoplastic cell lines and solid tumors. Furthermore, in vitro and in vivo studies have shown that EPO could promote human breast carcinoma growth by means of the binding with its receptor, although a clear function for EPO in this setting has not been yet established. While the human medical literature has been accumulating strong evidence on EPO's role in oncogenesis, to date, there are no veterinary reports focusing on such an issue. The aim of the present study was to investigate the immunohistochemical expression of EPOR in canine mammary gland dysplastic and neoplastic lesions. Our results show a weak to moderate EPOR expression in dysplastic glands, being immunoreactivity enhanced as the lesion shows an increasing malignant pattern. On the basis of these findings, this study describes, for the first time, the evidence for EPOR expression in canine mammary gland tumor and suggests a feasible EPO's role for canine mammary tumor progression.

Cyclin D1 expression in pre-cancerous and cancerous lesions of the canine mammary gland

Overexpression of cyclin D1, the regulatory subunit of cyclin-dependent kinases (cdk4 and cdk6) involved in cell cycle control, has often been found in breast cancer and other types of human cancer. Increased expression, or stability, of cyclin D1 molecules may cause sufficient cdk4 activation to produce retinoblastoma protein phosphorylation independently of mitogenic signals; this results in commitment of cells to the G1 phase at mitosis. In the present study, cyclin D1 expression was investigated in pre-cancerous and cancerous lesions of the canine mammary gland by a complex experimental approach, which included Western blot and immunohistochemical analysis of cyclin D1 and the related molecular system. Furthermore, to define relationships between cell growth and expression of cyclin D1, proliferative activity was studied by the AgNOR technique. The study provided the following information. Cyclin D1 overexpression was largely independent of the type of proliferative anomaly. Indeed, cyclin D1 was expressed in 60% of the pre-cancerous lesions and in 44% of cancerous lesions. Mitotic activity and cyclin D1 expression were related: mammary lesions that expressed cyclin D1 showed a high proliferative ratio, the opposite being true of cyclin D1-negative cell populations. This study may contribute to the establishment of an animal model for anti-cancer research based on cyclin D1 suppression or cdk inactivation, or both.

[Update on animal models for testing innovative antineoplastic strategies: the mammary tumor in dogs]

In this study, the authors describe a new possible animal model to test new anticancer therapies. The selected animals are domestic animals such as dogs, which develop spontaneous tumours very similar in morphology and biology to human ones, also in relation to similar environmental oncogenic pressures. Cycline D1 overexpression, which has both a prognostic and pathogenetic value, is usually detected in human tumours. Thus, the use of cycline-dependent kinases inhibitors could be of value in anticancer therapy. We studied spontaneous canine mammary tumours in order to test the above hypothesis. Immunohistochemistry, AgNOR and western blotting analysis were performed, and the results revealed that cycline D1 is associated with metabolic, morphological and protein expression patterns typical of proliferating cells. The same protein expression pattern, the use of human antibodies for detecting canine proteins and the availability of neoplastic tissue make these spontaneous canine tumours a reliable model.

rhVEGF and experimental rat skin flaps: systemic or local administration and morphological characteristics

Skin flap survival is a significant problem in skin surgery; in particular, inadequate arterial or venous blood supply results in necrosis of the distalmost portion. The aim of this study was to evaluate the ability of Vascular Endothelial Growth Factor (VEGF) of modifying the morphological features of skin flaps. Bilateral epigastric skin flaps were raised in 16 Wistar male rats. The epigastric artery and vein of the left flaps were clamped and then injected with rhVEGF (8 rats) or saline (8 rats). The right flaps were not clamped and received rhVEGF or saline systemically. The rats were euthanized on the seventh day and flap skin samples collected. Tissue fragments were subject to immunohistochemical (rhVEGF, VEGFr, VIII factor, CD34 antibodies), ultrastructural and morphostructural investigations. The results showed that rhVEGF improved the condition of flaps and that systemic administration was effective in promoting the development of an adequate vascular network.

Fecal neutral steroids in normal conditions and in patients with polyps or cancer of the large bowel

There is evidence suggesting that the excretion and conversion of neutral sterols in the human large bowel might be somewhat related to the development of colorectal cancer. Therefore, our objectives were: to characterize the excretion and the major pattern of sterol degradation in normal conditions, both in children and in adults; and to investigate if abnormalities of these parameters are frequent in patients with colorectal cancer or polyps. The study has been carried out in: 38 adult volunteers; 29 children divided into 4 age groups; 22 patients with colorectal cancer; 16 members of 6 families with adenomatosis coli; 15 members of 2 families with a high prevalence of multiple polyps or cancer of the large bowel; 12 subjects with colorectal polyps without familiality. With the subjects kept under metabolic control, fecal samples were collected for at least 3 days and analyzed by thin layer chromatography and gas-liquid chromatography. Total neutral steroid excretion was lower in children than in adult volunteers; in contrast, there was no significant difference between the latter and the other investigated group of patients with cancer or polyps, with values ranging between 230 and 680 mg/day. All the adult volunteers were "high converters" of cholesterol to its intestinal metabolites coprostanol and coprostanone [89 +/- 10% (SE) of degradation]. Children less than 1 year old degraded little or no cholesterol (10.4 +/- 6% of total neutral sterols), whereas with increasing age the fraction of conversion became more similar to that of adults. In patients with colorectal tumors 2 populations could be defined, one characterized by a large degradation of cholesterol and the other by little or no conversion. Low degradation of cholesterol was found in 3 of 6 families with adenomatosis coli. In conclusion, we did not find any significant difference in total neutral sterol excretion among controls, colorectal cancer patients, or subjects at risk. In adult volunteers the normal pattern of cholesterol degradation is characterized by a large conversion of cholesterol to its intestinal metabolites. In children this process changes with increasing age from an absolute "nonconverter" state (after birth) to the pattern typical of adults. Finally, in a minority of patients with either polyps or cancer of the large bowel and of their first-degree relatives, cholesterol is poorly degraded and represents the most abundant fecal sterol.