1,721,017 research outputs found
Expression and intracellular localization of Pyk2 in normal and v-src transformed chicken epiphyseal chondrocytes.
No full textThe expression and localization of prolin-rich tyrosine kinase 2 (Pyk2) were studied in chick embryo epiphyseal chondrocytes. Two immunoreactive bands were detected in chondrocytes, a major band with an apparent Mr of 123 kDa and a minor band with an apparent Mr of 68 kDa. The major band appears to migrate as a doublet with apparent Mr of 116/123 kDa. Increased levels of the three forms of Pyk2 were observed in v-src transformed chondrocytes as compared to control uninfected chondrocytes. Immunofluorescent staining shows that Pyk2 isclearly visible in the cytosol and in the perinuclear region of control and v-src-chondrocytes and displays a pattern very similar to the distributionof the mitochondrial marker Mito Tracker. More, immunofluorescent staining shows that Pyk2 is nuclear in most chondrocytes. By subcellular fractionation, the p116/123 Pyk2 doublet, was found to be accumulated mainly in the cytoplasm while the p68 Pyk2 form, was found to be accumulated exclusively in the nucleus. The differential nuclear/cytoplasmic distribution of the Pyk2 forms remains unchanged after v-Src-induced transformation. The p68 Pyk2 form could no longer be detected by using a N-terminus domain-specific anti-Pyk2 antibody. Consistently, Pyk2 immunoreactivity was restricted to the cytoplasm of control and v-src transformed chondrocytes. Thus it appears that the p68 Pyk2 form that accumulates in the nucleus has a deletion in the N-terminus region
Insights into Melanoma Fibroblast Populations and Therapeutic Strategy Perspectives: Friends or Foes?
No full text: Cutaneous melanoma (CM) is an aggressive and highly metastatic solid tumor associated with drug resistance. Before 2011, despite therapies based on cytokines or molecules inhibiting DNA synthesis, metastatic melanoma led to patient death within 18 months from diagnosis. However, recent studies on bidirectional interactions between melanoma cells and tumor microenvironment (TME) have had a significant impact on the development of new therapeutic strategies represented by targeted therapy and immunotherapy. In particular, the heterogeneous stromal fibroblast populations, including fibroblasts, fibroblast aggregates, myofibroblasts, and melanoma associated fibroblasts (MAFs), represent the most abundant cell population of TME and regulate cancer growth differently. Therefore, in this perspective article, we have highlighted the different impacts of fibroblast populations on cancer development and growth. In particular, we focused on the role of MAFs in sustaining melanoma cell survival, proliferation, migration and invasion, drug resistance, and immunoregulation. The important role of constitutively activated MAFs in promoting CM growth and immunoediting makes this cell type a promising target for cancer therapy
REARRANGEMENT LEADING TO THE EXPRESSION OF A PROMOTERLESS NEO GENE SPONTANEOUSLY OR FOLLOWING MUTAGENIC TREATMENTS IN STABLY TRANSFORMED RAT-2 FIBROBLASTS
No full textMetabolic flexibility in melanoma: A potential therapeutic target
No full textCutaneous melanoma (CM) represents one of the most metastasizing and drug resistant solid tumors. CM is characterized by a remarkable metabolic plasticity and an important connection between oncogenic activation and energetic metabolism. In fact, melanoma cells can use both cytosolic and mitochondrial compartments to produce adenosine triphosphate (ATP) during cancer progression. However, the CM energetic demand mainly depends on glycolysis, whose upregulation is strictly linked to constitutive activation of BRAF/MAPK pathway affected by BRAFV600E kinase mutant. Furthermore, the impressive metabolic plasticity of melanoma allows the development of resistance mechanisms to BRAF/MEK inhibitors (BRAFi/MEKi) and the adaptation to microenvironmental changes. The metabolic interaction between melanoma cells and tumor microenvironment affects the immune response and CM growth. In this review article, we describe the regulation of melanoma metabolic alterations and the metabolic interactions between cancer cells and microenvironment that influence melanoma progression and immune response. Finally, we summarize the hallmarks of melanoma therapies and we report BRAF/MEK pathway targeted therapy and mechanisms of metabolic resistance
Autocrine growth function of interleukin-1 and interleukin-6 molecules on human transformed B cells
No full textChondrocyte-matrix interactions and the control of cell shape and differentation in primary cultures of avian chondrocytes
No full textCytotoxic effect of diclofenac in the melanoma cell lines A2058 and SAN
No full textDiclofenac, a nonsteroidal anti-inflammatory drug (NSAID) widely used in clinical therapeutics, has cytotoxic effects and
induces apoptosis in many cultured cell lines. Many studies suggest that NSAIDs, and in particular the highly selective cyclooxigenase-2 inhibitors, could act as anticancer. We have investigated the involvement of mitochondrial dysfunction in the mechanism of diclofenac-induced apoptosis in the melanoma cell lines, A2058 and SAN, and in the human fibroblasts immortalized cell line BJ5ta. The analysis by phase contrast microscopy of diclofenac-treated cells showed the typical morphologic changes related to apoptosis only in A2058 and SAN cell lines. These effects appeared after a treatment with 150 lM diclofenac suggesting a preferential cytotoxic effect in the two melanoma cell lines. Propidium iodide incorporation followed by cytometric analysis showed an increase of apoptosis during diclofenac treatment. Since the caspase 3 represents the final effector of the caspase dependent apoptotic process we have also analysed its activity following diclofenac treatment. A marked increase of caspase 3 activity in the cell extracts of A2058 and SAN cells was evidenced by spectrofluorimetric analysis as well as the analysis of intracellular levels of bcl-2 confirmed the pro-apoptotic effect of diclofenac only in the melanoma cell lines. Furthermore, the cytotoxic effect of diclofenac in the melanoma cell lines was associated to a decrease of the antioxidant SOD2 protein levels. These preliminary data suggest that mitochondria could represent a diclofenac target and in particular the reduction of SOD2 protein contributes to the mitochondria dysfunction
A chimeric elongation factor containing the putative guanine nucleotide binding domain of archaeal EF-1 alpha and the M and C domains of eubacterial EF-Tu
No full textA recombinant chimeric elongation factor containing the region of EF-1 alpha from Sulfolobus solfataricus harboring the site for GDP and GTP binding and GTP hydrolysis (SsG) and domains M and C of Escherichia coli EF-Tu (EcMC) was studied. SsG-EcMC did not sustain poly(Phe) synthesis in either S. solfataricus or E. coli assay system. This was probably due to the inability of the chimera to interact with aa-tRNA. The three-dimensional modeling of SsG-EcMC indicated only small structural differences compared to the Thermus aquaticus EF-Tu in the ternary complex with aa-tRNA and GppNHp, which did not account for the observed inability to interact with aa-tRNA. The addition of the nucleotide exchange factor SsEF-1 beta was not required for poly(Phe) synthesis since the chimera was already able to exchange [(3)H]GDP for GTP at very high rate even at 0 degrees C. Compared to that of SsEF-1 alpha, the affinity of the chimera for guanine nucleotides was increased and the k(cat) of the intrinsic GTPase was 2-fold higher. The heat stability of SsG-EcMC was 3 and 13 degrees C lower than that displayed by SsG and SsEF-1alpha, respectively, but 30 degrees C higher than that of EcEF-Tu. This pattern remained almost the same if the melting curves of the proteins being investigated were considered instead. The chimeric elongation factor was more thermophilic than SsG and SsEF-1 alpha up to 70 degrees C; at higher temperatures, inactivation occurred
Markers of mitochondrial dysfunction during the diclofenac-induced apoptosis in melanoma cell lines
No full textMelanoma is an aggressive cutaneous cancer, whose incidence is growing in recent years, especially in
the younger population. The favorable therapy for this neoplasm consists in its early surgical excision;
otherwise, in case of late diagnosis, melanoma becomes very refractory to any conventional therapy.
Nevertheless, the acute inflammatory response occurring after excision of the primary melanoma can
affect the activation and/or regulation of melanoma invasion and metastasis. Nonsteroidal antiinflammatory
drugs (NSAIDs), widely employed in clinical therapy as cyclooxygenase inhibitors, also
display a cytotoxic effect on some cancer cell lines; therefore, their possible usage in combination with
conventional chemo- and radio-therapies of tumors is being considered. In particular, diclofenac, one of
the most common NSAIDs, displays its anti-proliferative effect in many tumor lines, through an alteration
of the cellular redox state. In this study, the possible anti-neoplastic potential of diclofenac on the human
melanoma cell lines A2058 and SAN was investigated, and a comparison was made with the results
obtained from the nonmalignant fibroblast cell line BJ-5ta. Either in A2058 or SAN, the diclofenac
treatment caused typical apoptotic morphological changes, as well as an increase of the number of subdiploid
nuclei; conversely, the same treatment on BJ-5ta had only a marginal effect. The observed
decrease of Bcl-2/Bax ratio and a parallel increase of caspase-3 activity confirmed the pro-apoptotic role
exerted by diclofenac in melanoma cells; furthermore, the drug provoked an increase of the ROS levels,
a decrease of mitochondrial superoxide dismutase (SOD2), the cytosolic translocation of both SOD2 and
cytochrome c, and an increase of caspase-9 activity. Finally, the cytotoxic effect of diclofenac was
amplified, in melanoma cells, by the silencing of SOD2. These data improve the knowledge on the effects
of diclofenac and suggest that new anti-neoplastic treatments should be based on the central role of
mitochondrion in cancer development; under this concern, the possible involvement of SOD2 as a novel
target could be considered
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