The SOCS1 (Suppressor Of Cytokine Signalling 1) protein is considered a tumour suppressor. Notably, the SOCS1 gene is frequently silenced in cancer by hypermethylation of its promoter. Besides ...blocking inflammation, SOCS1 tumour suppressor activity involves Met receptor inhibition and enhancement of p53 tumour suppressor activity. However, the role of SOCS1 in colorectal cancer (CRC) remains understudied and controversial. Here, we investigated SOCS1 relevance for CRC by querying gene expression datasets of human CRC specimens from The Cancer Genome Atlas (TCGA), and by SOCS1 gain/loss-of-function analyses in murine and human colon carcinoma cells. Our results show that SOCS1 mRNA levels in tumours were more often elevated than reduced with respect to matched adjacent normal tissue of CRC specimens (n = 41). The analysis of TCGA dataset of 431 CRC patients revealed no correlation between SOCS1 expression and overall survival. Overexpression of SOCS1 in CRC cells triggered cell growth enhancement, anchorage-independent growth and resistance to death stimuli, whereas knockdown of SOCS1 reduced these oncogenic features. Moreover, SOCS1 overexpression in mouse CT26 cells increased tumourigenesis in vivo. Biochemical analyses showed that SOCS1 pro-oncogenic activity correlated with the down-modulation of STAT1 expression. Collectively, these results suggest that SOCS1 may work as an oncogene in CRC.
A novel carbon composite was prepared from a mixture of coffee waste and clay with inorganic:organic ratio of 1.3 (CC-1.3). The mixture was pyrolysed at 700 °C. Considering the application of this ...adsorbent for removal of anionic dyes, the CC-1.3 was treated with a 6 mol L-1 HCl for 24 h to obtain ACC-1.3. Fourier transform infrared (FTIR), N2 adsorption/desorption curves, scanning electron microscope (SEM) and powder X-ray diffractometry (XRD) were used for characterisation of CC-1.3 and ACC-1.3 carbon adsorbents. The adsorbents were effectively utilised for removal of reactive blue 19 (RB-19) and reactive violet 5 (RV-5) textile dyes from aqueous solutions. The maximum amounts of RB-19 dye adsorbed at 25 °C are 63.59 (CC-1.3) and 110.6 mg g-1 (ACC-1.3), and 54.34 (CC-1.3) and 94.32 mg g-1 (ACC-1.3) for RV-5 dye. Four simulated dye-house effluents were used to test the application of the adsorbents for treatment of effluents.
Deregulation of receptor tyrosine kinases (RTK) contributes to the initiation and progression of intestinal-derived epithelial cancers, including colorectal cancer (CRC). However, the roles of the ...proximal signaling molecules engaged by RTKs in different oncogenic functions of CRC remain unclear.
Herein, the functional impact of expressing variant forms of the oncogenic Met receptor (Tpr-Met) that selectively recruit the adaptor proteins Grb2 or Shc was investigated in a model derived from normal intestinal epithelial cells (IEC-6). An RNA interference (RNAi) approach was used to define the requirement of Grb2 or Shc in Tpr-Met-transformed IEC-6 cells. Since Grb2 and Shc couple RTKs to the activation of the Ras/MEK/Erk and PI3K/Akt pathways, Erk and Akt phosphorylation/activation states were monitored in transformed IEC-6 cells, and a pharmacological approach was employed to provide insights into the roles of these pathways in oncogenic processes evoked by activated Met, and downstream of Grb2 and Shc.
We show, for the first time, that constitutive activation of either Grb2 or Shc signals in IEC-6 cells, promotes morphological transformation associated with down-regulation of E-cadherin, as well as increased cell growth, loss of growth contact inhibition, anchorage-independent growth, and resistance to serum deprivation and anoikis. Oncogenic activation of Met was revealed to induce morphological transformation, E-cadherin down-regulation, and protection against anoikis by mechanisms dependent on Grb2, while Shc was shown to be partly required for enhanced cell growth. The coupling of activated Met to the Ras/MEK/Erk and PI3K/Akt pathways, and the sustained engagement of Grb2 or Shc in IECs, was shown to trigger negative feedback, limiting the extent of activation of these pathways. Nonetheless, morphological alterations and E-cadherin down-regulation induced by the oncogenic Tpr-Met, and by Grb2 or Shc signals, were blocked by MEK, but not PI3K, inhibitors while the enhanced growth and resistance to anoikis induced by Tpr-Met were nearly abolished by co-treatment with both inhibitors.
Overall, these results identify Grb2 and Shc as central signaling effectors of Met-driven progression of intestinal epithelial-derived cancers. Notably, they suggest that Grb2 may represent a promising target for the design of novel CRC therapies.
The deregulation of Met/hepatocyte growth factor (HGF) receptor tyrosine kinase signaling constitutes a common event in colorectal cancers. However, the physiopathological functions of such a ...deregulation remain poorly understood. In the present study, we investigated the role of the deregulation of Met receptor in the neoplastic transformation of intestinal epithelial cells. To do so, the normal, well-established and characterized rat intestinal epithelial IEC-6 cells were transduced with a retrovirus carrying the oncogenic constitutive active form of Met receptor, Tpr-Met. Herein, we show that compared with control IEC-6 cells, Tpr-Met-IEC-6 cells exhibit enhanced proliferation, loss of growth-contact inhibition, cell morphological alterations, actin cytoskeletal reorganization, loss of E-cadherin expression and anchorage-independent growth. Moreover, Tpr-Met-IEC-6 cells are conferred the capacity to produce the proangiogenic factor VEGF and to reduce the potent antiangiogenic factor thrombospondin-1. Of significance, Tpr-Met-IEC-6 cells are endowed with the ability to elicit angiogenic responses and to form tumors and metastases in vivo. Hence, our study demonstrates for the first time that the sole oncogenic engagement of Met receptor in normal intestinal epithelial cells is sufficient to induce a wide array of cancerous biological processes that are fundamental to the initiation and malignant progression of colorectal cancers.
•The first use of GCxGC/qMS for the characterization of volatile compounds of artichoke leaves.•A total of 130 compounds were tentatively identified in the studied sample, 109 of which are reported ...for the first time in Cynara scolymus L.•Artichoke leaves are a potential source of volatile bioactive compounds.
Artichoke (Cynara scolymus L.) is well known due to its medicinal properties and, as a result, a large number of studies have been conducted to determine the chemical constituents produced by the plant. However, investigations were mainly focused on the non-volatile compounds, while the volatile constituents remained largely neglected. This study was aimed at obtaining a deeper understanding of the volatile composition of artichoke. For this propose, comprehensive two-dimensional gas chromatography coupled to a rapid scanning quadrupole mass spectrometer (GC×GC/qMS) and retention indices were used to improve the chemical characterization of volatiles from leaves. A total of 130 compounds were found, 109 of which are reported for the first time in C. scolymus L., including oxygenated monoterpenes, sesquiterpenes, oxygenated sesquiterpenes, norisoprenoids, lactones, alcohols, ketones and aldehydes. The major compounds were 1-octen-3-one (3.85%), (E)-2-hexenal (3.75%), benzene acetaldehyde (2.90%), 2,2-dimethyl-4-pentenal (2.81%), β-ionone (1.94%), furfural (1.65%), (E)-β-damescenone (1.59%), α-methyl-γ-butirolactone (1.53%), benzaldehyde (1.47%) and dihydroactinidiolide (1.44%). The comprehensive GC×GC/qMS approach enabled a greater number of analytes to be identified, approximately four times higher than that obtained for GC/qMS. Additionally, the results imply that artichoke leaves are a potential source of volatile bioactive compounds.
Caspases play in traffic Duclos, Catherine M; Champagne, Audrey; Carrier, Julie C ...
Cell death & disease,
03/2017, Volume:
8, Issue:
3
Journal Article
Peer reviewed
Open access
The unfolding of apoptosis involves the orchestrated proteolysis of hundreds of proteins,1 and to achieve efficacy the cell has evolved a three-step activation cascade. First, initiator caspases ...(caspases 8, 9, 10) are activated either by external death ligands triggering the formation of the death-inducing signaling complex (DISC; caspases 8 and10) or by the release of cytochrome c from mitochondria provoking the assembly of the apoptosome (caspase-9).2 Once activated, the initiator caspases directly cleave executioner caspases 3 and 7, leading to their activation. The third step is the caspase-3-mediated activation of the executioner caspase-6, a peptidase with a substrate preference similar to that of initiator caspases. In this manner, the cell amplifies the proteolytic activity of caspases to swiftly cause cell demise.
This work combines the analytical capability of GC×GC/TOFMS, the use of retention indices and adequate software tools for the study of essential oils of Piper regnellii (Miq.) C. DC. (pariparoba) ...growing wild in “cerrado” landscape, Central-West region, Brazil. The leaves, stems and flowers of P. regnellii generated essential oils with 163, 119 and 110 compounds tentatively identified, respectively. The major compounds in each essential oil were approximately the same, except dill apiole, which was concentrated more highly in the stems. The major compounds were: myrcene, anethole E and bicyclogermacrene (22%, 19% and 5%, respectively) in leaves, anethole E, dill apiole and myrcene (20%, 19% and 16%, respectively) in stems and anethole E, myrcene and bicyclogermacrene (24%, 18% and 9%, respectively) in flowers. This is the first time that this plant was analyzed by GC×GC/TOFMS and this technique allows identification of a higher number of compounds when compared to traditional one-dimensional chromatography.
•First use of GC × GC for analysis of essential oils from parts of Piper regnellii(Miq.) C. DC.•163, 119 and 110 compounds were tentatively identified in the studied essential oils.•The oils from different parts of the plant showed similar profiles only for the major compounds.
Hepatocyte growth factor receptor (Met) plays an important role in the progression of multiple cancer types. The overexpression of Met in DLD-1 colon carcinoma cells with kirsten rat sarcoma oncogene ...homolog (KRAS) oncogene activation resulted in enhanced subcutaneous and orthotopic tumor growth rate and increased metastatic potential. To elucidate the mechanism of this effect, we stably expressed kinase-inactive MetK1110A, Src homology 2 (SH2)-binding domain-inactive MetY1349/1356F, growth factor receptor-bound protein 2 (Grb2) non-binding MetN1358H and mutant receptors with ability to selectively recruit signaling proteins Grb2, src homology domain c-terminal adaptor homolog (Shc), phospholipase c-gamma (PLCγ) and p85 phosphatidyl inositol 3 kinase. As subcutaneous implants, DLD-1 cells that expressed the majority of these receptor constructs failed to recapitulate the tumor growth-enhancing effect of the wild-type Met receptor. The Grb2- and Shc-recruiting Met mutants demonstrated slight but consistent tumor-suppressive activity, whereas the expression of N1358H mutant stimulated tumor growth rate comparable with the wild-type receptor. This suggests that direct Grb2/Shc binding does not contribute to the tumor progression activity of Met receptor. The tumors expressing Grb2- and Shc-recruiting Met receptors demonstrated a marked loss in Grb2-associated adaptor protein 1 (Gab1) protein levels, which was not observed in the cell lines, consistent with a post-translationally regulated process. Moreover, a moderate level of Gab1 overexpression stimulated tumor growth. The findings suggest a delicate balance for intact Y1349/1356 SH2-binding domain to mediate the tumor progression activity of the coactivated Met–rat sarcoma oncogene homolog (RAS) pathways. Selectivity for specific adaptor protein involvement may be the key that determines the tissue- and cell-type specificity of Met-mediated tumorigenicity in human cancers.
The unfolding of apoptosis involves the cleavage of hundreds of proteins by the caspase family of cysteinyl peptidases. Among those substrates are proteins involved in intracellular vesicle ...trafficking with a net outcome of shutting down the crucial processes governing protein transport to organelles and to the plasma membrane. However, because of the intertwining of receptor trafficking and signaling, cleavage of specific proteins may lead to unintended consequences. Here we show that in apoptosis, sorting nexin 1 and 2 (SNX1 and SNX2), two proteins involved in endosomal sorting, are cleaved by initiator caspases and also by executioner caspase-6 in the case of SNX2. Moreover, SNX1 is cleaved at multiple sites, including following glutamate residues. Cleavage of SNX2 results in a loss of association with the endosome-to-
-Golgi network transport protein Vps35 and in a delocalization from endosomes of its associated partner Vps26. We also demonstrate that SNX2 depletion causes an increase in hepatocyte growth factor receptor tyrosine phosphorylation and Erk1/2 signaling in cells. Finally, we show that SNX2 mRNA and protein levels are decreased in colorectal carcinoma and that lower
gene expression correlates with an increase in cancer patient mortality. Our study reveals the importance to characterize the cleavage fragments produced by caspases of specific death substrates given their potential implication in the mechanism of regulation of physiological (signaling/trafficking) pathways or in the dysfunction leading to pathogenesis.