scholarly journals Silencing of the Insulin Receptor Isoform A Favors Formation of Type 1 Insulin-Like Growth Factor Receptor (IGF-IR) Homodimers and Enhances Ligand-Induced IGF-IR Activation and Viability of Human Colon Carcinoma Cells

Endocrinology ◽  
2010 ◽  
Vol 151 (4) ◽  
pp. 1418-1427 ◽  
Author(s):  
G. V. Brierley ◽  
S. L. Macaulay ◽  
B. E. Forbes ◽  
J. C. Wallace ◽  
L. J. Cosgrove ◽  
...  

Insulin receptor (IR) overexpression is common in cancers, with expression of the A isoform (IR-A, exon 11−) predominating over the B isoform. The IR-A signals a proliferative, antiapoptotic response to IGF-II, which itself can be secreted by tumors to establish an autocrine proliferative loop. Therefore, IGF-II signaling via the IR-A could mediate resistance to type 1 IGF receptor (IGF-IR) inhibitory drugs that are currently in development. This study addressed the role of the IR-A, using a small interfering RNA-based approach in SW480 human colon adenocarcinoma cells that coexpress the IGF-IR. Clonogenic survival was inhibited by depletion of the IGF-IR but not the IR-A, and dual receptor depletion had no greater effect than IGF-IR knockdown alone, suggesting that the IR-A could not compensate for IGF-IR loss. IGF-IR knockdown also resulted in a decrease in viability, whereas IR-A depletion resulted in increased viability. Consistent with this, upon IR-A depletion, we found a concomitant enhancement of IGF-IR activation by IGF-I and IGF-II, reduced formation of IGF-IR:IR-A hybrid receptors and increased IGF-IR homodimer formation. Together, these results suggest that IGF bioactivity is mediated more effectively by the IGF-IR than by the IR-A or receptor hybrids and that signaling via the IGF-IR is dominant to the IR-A in colon cancer cells that express both receptors.

2012 ◽  
Vol 393 (5) ◽  
pp. 413-420 ◽  
Author(s):  
Hyunjae Chung ◽  
Magda Hamza ◽  
Katerina Oikonomopoulou ◽  
Valérie Gratio ◽  
Mahmoud Saifeddine ◽  
...  

AbstractWe hypothesized that kallikrein-related peptidase 14 (KLK14) is produced by colonic tumors and can promote tumorigenesis by activating proteinase-activated receptors (PARs). We found that KLK14 is expressed in human colon adenocarcinoma cells but not in adjacent cancer-free tissue; KLK14 mRNA, present in colon cancer, leads to KLK14 protein expression and secretion; and KLK14 signals viaPAR-2 in HT-29 cells to cause (1) receptor activation/internalization, (2) increases in intracellular calcium, (3) stimulation of ERK1/2/MAP kinase phosphorylation, and (4) cell proliferation. We suggest that KLK14, acting via PAR-2, represents an autocrine/paracrine regulator of colon tumorigenesis.


Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 564
Author(s):  
Nayara Simas Frauches ◽  
Júlia Montenegro ◽  
Thuane Amaral ◽  
Joel Pimentel Abreu ◽  
Gabriela Laiber ◽  
...  

There is a significant indication of the beneficial health effects of fruit rich diets. Fruits of native plant species have noticeably different phytochemicals and bioactive effects. The aim of this work was to characterize and compare the constituents of jabuticaba (Myrciaria jaboticaba, MJ), jamun-berry (Syzygium cumini, SC), and malay-apple (Syzygium malaccense, SM) extracts and their influence on antioxidant activity in vitro and antiproliferative effects on human colon adenocarcinoma cells. According to the results, dried peel powders (DP) have a high anthocyanin content, phenolic compounds, and antioxidant activity when compared to freeze dried extracts (FD). M. jaboticaba dried peel powder extract had a higher total anthocyanin and phenolic compounds content (802.90 ± 1.93 and 2152.92 ± 43.95 mg/100 g, respectively). A reduction in cell viability of HT-29 cells after treatment with M. jaboticaba extracts (DP-MJ and FD-MJ) was observed via MTT assay. Flow cytometry showed that the treatment with the anthocyanin-rich extracts from MJ, SC, and SM had an inhibitory impact on cell development due to G2/M arrest and caused a rise in apoptotic cells in relation to the control group. The findings of this study highlight the potential of peel powders from Myrtaceae fruits as an important source of natural antioxidants and a protective effect against colon adenocarcinoma.


2008 ◽  
Vol 102 (2) ◽  
pp. 207-214 ◽  
Author(s):  
Paola Palozza ◽  
Diana Bellovino ◽  
Rossella Simone ◽  
Alma Boninsegna ◽  
Francesco Cellini ◽  
...  

Lycopene β-cyclase (tlcy-b) tomatoes, obtained by modulating carotenogenesis via genetic engineering, contain a large amount of β-carotene, as clearly visible by their intense orange colour. In the present study we have subjected tlcy-b tomatoes to an in vitro simulated digestion and analysed the effects of digestate on cell proliferation. To this aim we used HT-29 human colon adenocarcinoma cells, grown in monolayers, as a model. Digested tomatoes were diluted (20 ml, 50 ml and 100 ml/l) in culture medium and added to the cells for different incubation times (24 h, 48 h and 72 h). Inhibition of cell growth by tomato digestate was dose-dependent and resulted from an arrest of cell cycle progression at the G0/G1 and G2/M phase and by apoptosis induction. A down-regulation of cyclin D1, Bcl-2 and Bcl-xl expression was observed. We also found that heat treatment of samples before digestion enhanced β-carotene release and therefore cell growth inhibition. To induce with purified β-carotene solubilised in tetrahydrofuran the same cell growth inhibition obtained with the tomato digestate, a higher amount of the carotenoid was necessary, suggesting that β-carotene micellarised during digestion is utilised more efficiently by the cells, but also that other tomato molecules, reasonably made available during digestion, may be present and cooperate with β-carotene in promoting cell growth arrest.


Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2569 ◽  
Author(s):  
Lana Rosa ◽  
Nathállia Jordão ◽  
Nathália da Costa Pereira Soares ◽  
Joelma deMesquita ◽  
Mariana Monteiro ◽  
...  

Colon cancer is the second most common cause of cancer deaths in the USA and Europe. Despite aggressive therapies, many tumors are resistant to current treatment protocols and epidemiological data suggest that diet is a major factor in the etiology of colon cancer. This study aimed to evaluate the antioxidant activity and the influence of 3,4-dihydroxyphenylacetic (3,4-DHPAA), p-coumaric (p-CoA), vanillic (VA) and ferulic (FA) acids on cell viability, cell cycle progression, and rate of apoptosis in human colon adenocarcinoma cells (HT-29). The results showed that all compounds tested reduce cell viability in human colon cancer cells. 3,4-DHPAA promoted the highest effect antiproliferative with an increase in the percentage of cells in G0/G1 phase, accompanied by a reduction of cells in G2/M phase. Cell cycle analysis of VA and FA showed a decrease in the proportion of cells in G0/G1 phase (10.0 µM and 100.0 µM). p-CoA and FA acids increased the percentage of apoptotic cells and non-apoptotic cells. 3,4-DHPAA seems to be the substance with the greatest potential for in vivo studies, opening thus a series of perspectives on the use of these compounds in the prevention and treatment of colon cancer.


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