Molecular, cellular and physiological characterization of the cancer cachexia-inducing C26 colon carcinoma in mouse

BACKGROUND: The majority of cancer patients experience dramatic weight loss, due to cachexia and consisting of skeletal muscle and fat tissue wasting. Cachexia is a negative prognostic factor, interferes with therapy and worsens the patients' quality of life by affecting muscle function. Mice bearing ectopically-implanted C26 colon carcinoma are widely used as an experimental model of cancer cachexia. As part of the search for novel clinical and basic research applications for this experimental model, we characterized novel cellular and molecular features of C26-bearing mice. METHODS: A fragment of C26 tumor was subcutaneously grafted in isogenic BALB/c mice. The mass growth and proliferation rate of the tumor were analyzed. Histological and cytofluorometric analyses were used to assess cell death, ploidy and differentiation of the tumor cells. The main features of skeletal muscle atrophy, which were highlighted by immunohistochemical and electron microscopy analyses, correlated with biochemical alterations. Muscle force and resistance to fatigue were measured and analyzed as major functional deficits of the cachectic musculature. RESULTS: We found that the C26 tumor, ectopically implanted in mice, is an undifferentiated carcinoma, which should be referred to as such and not as adenocarcinoma, a common misconception. The C26 tumor displays aneuploidy and histological features typical of transformed cells, incorporates BrdU and induces severe weight loss in the host, which is largely caused by muscle wasting. The latter appears to be due to proteasome-mediated protein degradation, which disrupts the sarcomeric structure and muscle fiber-extracellular matrix interactions. A pivotal functional deficit of cachectic muscle consists in increased fatigability, while the reported loss of tetanic force is not statistically significant following normalization for decreased muscle fiber size. CONCLUSIONS: We conclude, on the basis of the definition of cachexia, that ectopically-implanted C26 carcinoma represents a well standardized experimental model for research on cancer cachexia. We wish to point out that scientists using the C26 model to study cancer and those using the same model to study cachexia may be unaware of each other's works because they use different keywords; we present strategies to eliminate this gap and discuss the benefits of such an exchange of knowledge

Different expression of Pp-LTP1 and accumulation of Pru p 3 in fruits of two Prunus persica L. Batsch genotypes

The full-length cDNAs of Pp-LTP1 and Pp-LTP2, two members of the lipid transfer protein (LTP) multigene family in peach (Prunus persica L. Batsch), have been isolated along with the proximal promoter and the complete genomic sequence of Pp-LTP1. As observed in other plant species, Pp-LTP1 is organized in two exons and, according to the deduced amino acid sequence of the secreted protein, it encodes the 9 kDa allergenic protein Pru p 3. Pp-LTP1 transcripts and Pru p 3 protein markedly accumulate in epicarp of ripe fruit in all of the peach and nectarine varieties examined (including 'Royal Gem') with the exception of 'Rita Star' that shows weak specific mRNA hybridization signal and no Pru p 3 accumulation. SDS-PAGE clearly displays a different banding pattern in correspondence of 9 kDa between 'Rita Star' and 'Royal Gem'. In immunoblotting analysis, performed using sera of eight LTP pos+ patients, a strong band is present when using 'Royal Gem' epicarp extract but not in the case of 'Rita Star'. According to these data, 'Rita Star' appears an interesting model to better elucidate the role of LTP in fruit development and allergenic reactions

Evolution of the allergenic potential in peach and nectarine fruits during ripening

According to recent epidemiological studies, in many countries food allergies increased strongly during recent decades. Allergies to fruits represent also an emerging problem and studies should be addressed to identify allergens, evaluate the allergenic potential of different species and varieties and, possibly, produce hypoallergenic fruits. In peach, the major allergen has been identified as a Lipid Transfer Protein (LTP) and in the present research the evolution of the allergenic potential of different peach and nectarine varieties has been monitored throughout ripening and in relation to postharvest treatments. Fruits of peach cv. \u2018Royal Gemm\u2019, \u2018Zorzi\u2019, of nectarine cv. \u2018Rita Star\u2019, \u2018Early Giant\u2019 and \u2018Maria Dorata\u2019, and of flat type (Platicarpa) were harvested in correspondence of commercial ripeness and allowed to ripen at room temperature or stored at 4\ub0C for 3 weeks. Northern blot analyses were carried out on total RNA extracted from epicarp and mesocarp to study Pp-LTP1 gene expression. Immunological studies were performed by means of a polyclonal antibody raised against the purified protein. Expression analysis showed that Pp-LTP1 transcripts accumulated only in the epicarp. With the exception of cv. \u2018Rita Star\u2019 the strongest accumulations have been detected in epicarp of all varieties at harvest. With the exception of Platicarpa, a decreasing trend of expression was observed in fruits kept in air and at 4\ub0C. Western blots revealed the presence of LTP only in epicarp of all studied varieties, but not in \u2018Rita Star\u2019, and showed that the protein markedly increased in full ripe fruits maintained in air. This might indicate the presence of a lag between gene transcription and accumulation of secreted functional LTP. According to these results, cv. \u2018Rita Star\u2019 appears to be a variety with a reduced allergenic potential

V1a AVP receptor is required for neurohypophyseal hormonedependent differentiation in C2C12 cells

Vasopressin (AVP), oxytocin (OT) and related peptides induce differentiation and hypertrophy in myogenic cells expressing the V1a-vasopressin receptor (V1aR) or the oxytocin receptor (OTR). Either receptor can transduce both ligand signals. Binding of AVP and OT to the V1aR the target cells activates phosphatidylinositol hydrolysis, which in turn releases Ca2+ from internal stores. The AVP-dependent increase in cytosolic Ca2+ induces the activation of calcium/calmodulin-dependent kinase (CaMK) and calcineurin signaling, two pathways required for the full expression of the differentiated phenotype. Here we investigate the role of V1aR in myogenesis and hypertrophy by ectopically restoring V1aR expression and function using the C2C12 cell line, which is an experimental model of satellite cells that do not respond to AVP treatment. Our results show that AVP treatment enhances myogenic differentiation in V1aR-transfected C2C12 cultures alone. Moreover, calcium imaging analyses performed in individual control and V1aR-transfected C2C12 cells demonstrated that the presence of V1aR is sufficient to make C2C12 cells responsive to neurohypophyseal hormones stimulation, as demonstrated by the rapid and sustained release of calcium from internal stores observed in V1aR-transfected cells. These data demonstrate that, despite the high levels of OTR expressed by C2C12 cells, both AVP and OT failed to stimulate the differentiation program, thereby indicating that the presence of V1aR is essential to mediate the effects of neurohypophyseal hormones on myogenic differentiation in C2C12 cells

Molecular, cellular and physiological characterization of the cancer cachexia-inducing C26 colon carcinoma in mouse

Abstract Background The majority of cancer patients experience dramatic weight loss, due to cachexia and consisting of skeletal muscle and fat tissue wasting. Cachexia is a negative prognostic factor, interferes with therapy and worsens the patients' quality of life by affecting muscle function. Mice bearing ectopically-implanted C26 colon carcinoma are widely used as an experimental model of cancer cachexia. As part of the search for novel clinical and basic research applications for this experimental model, we characterized novel cellular and molecular features of C26-bearing mice. Methods A fragment of C26 tumor was subcutaneously grafted in isogenic BALB/c mice. The mass growth and proliferation rate of the tumor were analyzed. Histological and cytofluorometric analyses were used to assess cell death, ploidy and differentiation of the tumor cells. The main features of skeletal muscle atrophy, which were highlighted by immunohistochemical and electron microscopy analyses, correlated with biochemical alterations. Muscle force and resistance to fatigue were measured and analyzed as major functional deficits of the cachectic musculature. Results We found that the C26 tumor, ectopically implanted in mice, is an undifferentiated carcinoma, which should be referred to as such and not as adenocarcinoma, a common misconception. The C26 tumor displays aneuploidy and histological features typical of transformed cells, incorporates BrdU and induces severe weight loss in the host, which is largely caused by muscle wasting. The latter appears to be due to proteasome-mediated protein degradation, which disrupts the sarcomeric structure and muscle fiber-extracellular matrix interactions. A pivotal functional deficit of cachectic muscle consists in increased fatigability, while the reported loss of tetanic force is not statistically significant following normalization for decreased muscle fiber size. Conclusions We conclude, on the basis of the definition of cachexia, that ectopically-implanted C26 carcinoma represents a well standardized experimental model for research on cancer cachexia. We wish to point out that scientists using the C26 model to study cancer and those using the same model to study cachexia may be unaware of each other's works because they use different keywords; we present strategies to eliminate this gap and discuss the benefits of such an exchange of knowledge.</p