37 research outputs found
New Castanospermine Glycoside Analogues Inhibit Breast Cancer Cell Proliferation and Induce Apoptosis without Affecting Normal Cells
sp2-Iminosugar-type castanospermine analogues have been shown to exhibit anti-tumor activity. However, their effects on cell proliferation and apoptosis and the molecular mechanism at play are not fully understood. Here, we investigated the effect of two representatives, namely the pseudo-S- and C-octyl glycoside 2-oxa-3-oxocastanospermine derivatives SO-OCS and CO-OCS, on MCF-7 and MDA-MB-231 breast cancer and MCF-10A mammary normal cell lines. We found that SO-OCS and CO-OCS inhibited breast cancer cell viability in a concentration- and time-dependent manner. This effect is specific to breast cancer cells as both molecules had no impact on normal MCF-10A cell proliferation. Both drugs induced a cell cycle arrest. CO-OCS arrested cell cycle at G1 and G2/M in MCF-7 and MDA-MB-231cells respectively. In MCF-7 cells, the G1 arrest is associated with a reduction of CDK4 (cyclin-dependent kinase 4), cyclin D1 and cyclin E expression, pRb phosphorylation, and an overexpression of p21Waf1/Cip1. In MDA-MB-231 cells, CO-OCS reduced CDK1 but not cyclin B1 expression. SO-OCS accumulated cells in G2/M in both cell lines and this blockade was accompanied by a decrease of CDK1, but not cyclin B1 expression. Furthermore, both drugs induced apoptosis as demonstrated by the increased percentage of annexin V positive cells and Bax/Bcl-2 ratio. Interestingly, in normal MCF-10A cells the two drugs failed to modify cell proliferation, cell cycle progression, cyclins, or CDKs expression. These results demonstrate that the effect of CO-OCS and SO-OCS is triggered by both cell cycle arrest and apoptosis, suggesting that these castanospermine analogues may constitute potential anti-cancer agents against breast cancer. © 2013 Allan et al.Peer Reviewe
New Castanospermine Glycoside Analogues Inhibit Breast Cancer Cell Proliferation and Induce Apoptosis without Affecting Normal Cells
sp2-Iminosugar-type castanospermine analogues have been shown to exhibit anti-tumor activity. However, their effects on cell proliferation and apoptosis and the molecular mechanism at play are not fully understood. Here, we investigated the effect of two representatives, namely the pseudo-S- and C-octyl glycoside 2-oxa-3-oxocastanospermine derivatives SO-OCS and CO-OCS, on MCF-7 and MDA-MB-231 breast cancer and MCF-10A mammary normal cell lines. We found that SO-OCS and CO-OCS inhibited breast cancer cell viability in a concentration- and time-dependent manner. This effect is specific to breast cancer cells as both molecules had no impact on normal MCF-10A cell proliferation. Both drugs induced a cell cycle arrest. CO-OCS arrested cell cycle at G1 and G2/M in MCF-7 and MDA-MB-231cells respectively. In MCF-7 cells, the G1 arrest is associated with a reduction of CDK4 (cyclin-dependent kinase 4), cyclin D1 and cyclin E expression, pRb phosphorylation, and an overexpression of p21Waf1/Cip1. In MDA-MB-231 cells, CO-OCS reduced CDK1 but not cyclin B1 expression. SO-OCS accumulated cells in G2/M in both cell lines and this blockade was accompanied by a decrease of CDK1, but not cyclin B1 expression. Furthermore, both drugs induced apoptosis as demonstrated by the increased percentage of annexin V positive cells and Bax/Bcl-2 ratio. Interestingly, in normal MCF-10A cells the two drugs failed to modify cell proliferation, cell cycle progression, cyclins, or CDKs expression. These results demonstrate that the effect of CO-OCS and SO-OCS is triggered by both cell cycle arrest and apoptosis, suggesting that these castanospermine analogues may constitute potential anti-cancer agents against breast cancerMinisterio de EconomĂa y Competitividad SAF2010-15670 y CTQ2010-1584
Functional cooperation between KCa3.1 and TRPC1 channels in human breast cancer: Role in cell proliferation and patient prognosis
Intracellular Ca2+ levels are important regulators of cell cycle and proliferation. We, and others, have previously reported the role of KCa3.1 (KCNN4) channels in regulating the membrane potential and the Ca2+ entry in association with cell proliferation. However, the relevance of KC3.1 channels in cancer prognosis as well as the molecular mechanism of Ca2+ entry triggered by their activation remain undetermined. Here, we show that RNAi-mediated knockdown of KCa3.1 and/or TRPC1 leads to a significant decrease in cell proliferation due to cell cycle arrest in the G1 phase. These results are consistent with the observed upregulation of both channels in synchronized cells at the end of G1 phase. Additionally, knockdown of TRPC1 suppressed the Ca2+ entry induced by 1-EBIO-mediated KCa3.1 activation, suggesting a functional cooperation between TRPC1 and KCa3.1 in the regulation of Ca2+ entry, possibly within lipid raft microdomains where these two channels seem to co-localize. We also show significant correlations between KCa3.1 mRNA expression and poor patient prognosis and unfavorable clinical breast cancer parameters by mining large datasets in the public domain. Together, these results highlight the importance of KCa3.1 in regulating the proliferative mechanisms in breast cancer cells as well as in providing a promising novel target in prognosis and therap
Expression of TRPC6 channels in human epithelial breast cancer cells
<p>Abstract</p> <p>Background</p> <p>TRP channels have been shown to be involved in tumour generation and malignant growth. However, the expression of these channels in breast cancer remains unclear. Here we studied the expression and function of endogenous TRPC6 channels in a breast cancer cell line (MCF-7), a human breast cancer epithelial primary culture (hBCE) and in normal and tumour breast tissues.</p> <p>Methods</p> <p>Molecular (Western blot and RT-PCR), and immunohistochemical techniques were used to investigate TRPC6 expression. To investigate the channel activity in both MCF-7 cells and hBCE we used electrophysiological technique (whole cell patch clamp configuration).</p> <p>Results</p> <p>A non selective cationic current was activated by the oleoyl-2-acetyl-sn-glycerol (OAG) in both hBCE and MCF-7 cells. OAG-inward current was inhibited by 2-APB, SK&F 96365 and La<sup>3+</sup>. TRPC6, but not TRPC7, was expressed both in hBCE and in MCF-7 cells. TRPC3 was only expressed in hBCE. Clinically, TRPC6 mRNA and protein were elevated in breast carcinoma specimens in comparison to normal breast tissue. Furthermore, we found that the overexpression of TRPC6 protein levels were not correlated with tumour grades, estrogen receptor expression or lymph node positive tumours.</p> <p>Conclusion</p> <p>Our results indicate that TRPC6 channels are strongly expressed and functional in breast cancer epithelial cells. Moreover, the overexpression of these channels appears without any correlation with tumour grade, ER expression and lymph node metastasis. Our findings support the idea that TRPC6 may have a role in breast carcinogenesis.</p
Crosstalk between Ca(2+) Signaling and Cancer Stemness: The Link to Cisplatin Resistance.
International audienceIn the fight against cancer, therapeutic strategies using cisplatin are severely limited by the appearance of a resistant phenotype. While cisplatin is usually efficient at the beginning of the treatment, several patients endure resistance to this agent and face relapse. One of the reasons for this resistant phenotype is the emergence of a cell subpopulation known as cancer stem cells (CSCs). Due to their quiescent phenotype and self-renewal abilities, these cells have recently been recognized as a crucial field of investigation in cancer and treatment resistance. Changes in intracellular calcium (Ca(2+)) through Ca(2+) channel activity are essential for many cellular processes such as proliferation, migration, differentiation, and survival in various cell types. It is now proved that altered Ca(2+) signaling is a hallmark of cancer, and several Ca(2+) channels have been linked to CSC functions and therapy resistance. Moreover, cisplatin was shown to interfere with Ca(2+) homeostasis; thus, it is considered likely that cisplatin-induced aberrant Ca(2+) signaling is linked to CSCs biology and, therefore, therapy failure. The molecular signature defining the resistant phenotype varies between tumors, and the number of resistance mechanisms activated in response to a range of pressures dictates the global degree of cisplatin resistance. However, if we can understand the molecular mechanisms linking Ca(2+) to cisplatin-induced resistance and CSC behaviors, alternative and novel therapeutic strategies could be considered. In this review, we examine how cisplatin interferes with Ca(2+) homeostasis in tumor cells. We also summarize how cisplatin induces CSC markers in cancer. Finally, we highlight the role of Ca(2+) in cancer stemness and focus on how they are involved in cisplatin-induced resistance through the increase of cancer stem cell populations and via specific pathways
Activation of the calcium-sensing receptor by high calcium induced breast cancer cell proliferation and TRPC1 cation channel over-expression potentially through EGFR pathways
International audienceThe calcium sensing receptor (CaR) is a G-protein-coupled receptor that is activated by extracellular calcium ([Ca(2+)](o)). In MCF-7 human breast cancer cells, we previously reported that treatment with [Ca(2+)](o) for 24h leads to an over-expression of the Transient Receptor Potential Canonical 1 (TRPC1) cation channel and cell proliferation. Both involve the extracellular signal-regulated Kinases 1 & 2 (ERK1/2). MCF-7 also expressed epidermal growth factor receptor (EGFR) which is involved in cell proliferation through ERK1/2. Therefore, we investigated the cross-talk between CaR and EGFR in mediating ERK1/2 phosphorylation, TRPC1 over-expression and cell proliferation. Our data show that both high [Ca(2+)](o) and EGF phosphorylate ERK1/2. Furthermore, inhibition of EGFR kinase and matrix metalloproteinases (MMPs) reduced the overall effects mediated by [Ca(2+)](o) such as activation of ERK1/2, expression of TRPC1 and cell proliferation. They indicate the important role of the CaR-EGFR-ERK axis in transmitting mitogenic signals generated by high [Ca(2+)](o) in MCF-7 cells
K+ channels and cell cycle progression in tumor cells
K+ ions play a major role in many cellular processes. The deregulation of K+ signaling is associated with a variety of diseases such as hypertension, atherosclerosis, or diabetes. K+ ions are important for setting the membrane potential, the driving force for Ca2+ influx, and regulate volume of growing cells. Moreover, it is increasingly recognized that K+ channels control cell proliferation through a novel signaling mechanisms triggered and modulated independently of ion fluxes. In cancer, aberrant expression, regulation and/or sublocalization of K+ channels can alter the downstream signals that converge on the cell cycle machinery. Various K+ channels are involved in cell cycle progression and are needed only at particular stages of the cell cycle. Consistent with this idea, the expression of Eag1 and HERG channels fluctuate along the cell cycle. Despite of acquired knowledge, our understanding of K+ channels functioning in cancer cells requires further studies. These include identifying the molecular mechanisms controling the cell cycle machinery. By understanding how K+ channels regulate cell cycle progression in cancer cells, we will gain insights into how cancer cells subvert the need for K+ signal and its downstream targets to proliferate
Synthesis of N-, S-, and C-glycoside castanospermine analogues with selective neutral α-glucosidase inhibitory activity as antitumour agents
3 páginas, 2 figuras, 1 tabla, 1 esquemasp2-Iminosugar-type castanospermine analogues bearing an α-configured N-, S-, or C-linked pseudoanomeric group have been designed as selective inhibitors of the neutral α-glucosidases involved in N-glycoprotein processing; evaluation in breast cancer cell growth indicated a significant antiproliferative potential that was dependent on the nature of the pseudoanomeric group.This work was supported by the Spanish Ministerio de EducaciĂłn y Ciencia (contract numbers CTQ2006-15515-C02-01/BQU, CTQ2009-14551-C02-01/BQU and TQ2007-61180/PPQ) and the Junta de AndalucĂa.Peer reviewe
Intermediate conductance Ca2+ activated K+ channels are expressed and functional in breast adenocarcinomas: correlation with tumour grade and metastasis status
K+ channels are key molecules in the
progression of several cancer types and are considered to
be potential targets for cancer therapy.
In this study, we investigated the intermediateconductance
Ca2+-activated K+ channels (hKCa3.1)
expression in both breast carcinoma (BC) specimens and
human breast cancer epithelial primary cell cultures
(hBCE) using immuno-histochemistry (60 samples),
quantitative Real-Time RT-PCR (30 samples) and
Western blot assay (30 samples). We also looked at
whether or not the expression of these channels is
correlated with breast carcinomas grade tumours and
metastasis status. Furthermore, we characterized the
hKCa3.1 channel activity in hBCE cells by using the
Whole Cell Patch Clamp Technique.
We found that hKCa3.1 transcripts and proteins were
expressed in both BC samples and hBCE cells.
Clinicopathologic evaluation indicated a significant
correlation between hKCa3.1-expression and tumour
grade. hKCa3.1 mRNA and protein were more highly
expressed in grade III tumours than in both grades I and
II. However, the hKCa3.1 expression-increase according
to grade was only observed in tumours with negative
metastasis status. Moreover, the hKCa3.1 channels
expressed in hBCE cells are functional. This was
attested by patch-clamp recordings showing typical
hKCa3.1-mediated currents in these cells. In conclusion,
these data suggest that hKCa3.1 might contribute to
breast tumour-progression and can serve as a useful prognostic marker for breast cance
Voltage-gated ion channels, new targets in anti-cancer research.
International audienceCancer is one of the leading causes of mortality in the world. This is a complex disease involving many steps with proper signalling pathways. Early detection and treatment of cancers have increased survival and improved clinical outcome. However, novel strategies based on new interesting targets are needed to improve the conventional treatments. A few years ago, it appeared that some particular transmembrane proteins, ion channels, may be involved in the development of the disease. Since then, their role in cancer cell properties such as proliferation, migration and invasion begins to be unravelled. These proteins have been widely studied in non cancerous cells as well as in pathologies involving excitable cells and thus, their pharmacology are quite well known. In this review, we summarize the present knowledge about the role of different ion channels in some aspects of the development of tumours, mainly proliferation, migration and invasion. A particular emphasis is done on promising new patents