IK1 channel activity contributes to cisplatin sensitivity of human epidermoid cancer cells

2008 ◽  
Vol 294 (6) ◽  
pp. C1398-C1406 ◽  
Author(s):  
Elbert L. Lee ◽  
Yuichi Hasegawa ◽  
Takahiro Shimizu ◽  
Yasunobu Okada

Cisplatin, a platinum-based drug, is an important weapon against many types of cancer. It induces apoptosis by forming adducts with DNA, although many aspects of its mechanism of action remain to be clarified. Previously, we found a role for the volume-sensitive, outwardly rectifying Cl− channel in cisplatin-induced apoptosis. To investigate the possibility that cation channels also have a role in the cellular response to cisplatin, we examined the activity of cation channels in cisplatin-sensitive KB-3-1 (KB) epidermoid cancer cells by the whole cell patch-clamp method. A cation channel in KB cells, activated by hypotonic stress, was identified as the Ca2+-activated, intermediate-conductance K+ (IK1) channel on the basis of its requirement for intracellular Ca2+, its blockage by the blockers clotrimazole and triarylmethane-34, and its suppression by a dominant-negative construct. Activity of this channel was not observed in KCP-4 cells, a cisplatin-resistant cell line derived from KB cells, and its molecular expression, observed by semiquantitative RT-PCR and immunostaining, appeared much reduced. Cell volume measurements confirmed a physiological role for the IK1 channel as a component of the volume-regulatory machinery in KB cells. A possible role of the IK1 channel in cisplatin-induced apoptosis was investigated. It was found that clotrimazole and triarylmethane-34 inhibited a cisplatin-induced decrease in cell viability and increase in caspase-3/7 activity, whereas 1-ethyl-2-benzimidazolinone, an activator of the channel, had the opposite effect. Thus IK1 channel activity appears to mediate, at least in part, the response of KB cells to cisplatin treatment.

2004 ◽  
Vol 15 (7) ◽  
pp. 3266-3284 ◽  
Author(s):  
Romaine Ingrid Fernando ◽  
Jay Wimalasena

Estrogens such as 17-β estradiol (E2) play a critical role in sporadic breast cancer progression and decrease apoptosis in breast cancer cells. Our studies using estrogen receptor-positive MCF7 cells show that E2 abrogates apoptosis possibly through phosphorylation/inactivation of the proapoptotic protein BAD, which was rapidly phosphorylated at S112 and S136. Inhibition of BAD protein expression with specific antisense oligonucleotides reduced the effectiveness of tumor necrosis factor-α, H2O2, and serum starvation in causing apoptosis. Furthermore, the ability of E2 to prevent tumor necrosis factor-α-induced apoptosis was blocked by overexpression of the BAD S112A/S136A mutant but not the wild-type BAD. BAD S112A/S136A, which lacks phosphorylation sites for p90RSK1 and Akt, was not phosphorylated in response to E2 in vitro. E2 treatment rapidly activated phosphatidylinositol 3-kinase (PI-3K)/Akt and p90RSK1 to an extent similar to insulin-like growth factor-1 treatment. In agreement with p90RSK1 activation, E2 also rapidly activated extracellular signal-regulated kinase, and this activity was down-regulated by chemical and biological inhibition of PI-3K suggestive of cross talk between signaling pathways responding to E2. Dominant negative Ras blocked E2-induced BAD phosphorylation and the Raf-activator RasV12T35S induced BAD phosphorylation as well as enhanced E2-induced phosphorylation at S112. Chemical inhibition of PI-3K and mitogen-activated protein kinase kinase 1 inhibited E2-induced BAD phosphorylation at S112 and S136 and expression of dominant negative Ras-induced apoptosis in proliferating cells. Together, these data demonstrate a new nongenomic mechanism by which E2 prevents apoptosis.


2005 ◽  
Vol 391 (3) ◽  
pp. 503-511 ◽  
Author(s):  
Natalia V. Oleinik ◽  
Natalia I. Krupenko ◽  
David G. Priest ◽  
Sergey A. Krupenko

A folate enzyme, FDH (10-formyltetrahydrofolate dehydrogenase; EC 1.5.1.6), is not a typical tumour suppressor, but it has two basic characteristics of one, i.e. it is down-regulated in tumours and its expression is selectively cytotoxic to cancer cells. We have recently shown that ectopic expression of FDH in A549 lung cancer cells induces G1 arrest and apoptosis that was accompanied by elevation of p53 and its downstream target, p21. It was not known, however, whether FDH-induced apoptosis is p53-dependent or not. In the present study, we report that FDH-induced suppressor effects are strictly p53-dependent in A549 cells. Both knockdown of p53 using an RNAi (RNA interference) approach and disabling of p53 function by dominant-negative inhibition with R175H mutant p53 prevented FDH-induced cytotoxicity in these cells. Ablation of the FDH-suppressor effect is associated with an inability to activate apoptosis in the absence of functional p53. We have also shown that FDH elevation results in p53 phosphorylation at Ser-6 and Ser-20 in the p53 transactivation domain, and Ser-392 in the C-terminal domain, but only Ser-6 is strictly required to mediate FDH effects. Also, translocation of p53 to the nuclei and expression of the pro-apoptotic protein PUMA (Bcl2 binding component 3) was observed after induction of FDH expression. Elevation of FDH in p53 functional HCT116 cells induced strong growth inhibition, while growth of p53-deficient HCT116 cells was unaffected. This implies that activation of p53-dependent pathways is a general downstream mechanism in response to induction of FDH expression in p53 functional cancer cells.


2000 ◽  
Vol 20 (1) ◽  
pp. 205-212 ◽  
Author(s):  
Spencer B. Gibson ◽  
Ryan Oyer ◽  
Aaron C. Spalding ◽  
Steven M. Anderson ◽  
Gary L. Johnson

ABSTRACT Chemotherapeutic genotoxins induce apoptosis in epithelial-cell-derived cancer cells. The death receptor ligand TRAIL also induces apoptosis in epithelial-cell-derived cancer cells but generally fails to induce apoptosis in nontransformed cells. We show here that the treatment of four different epithelial cell lines with the topoisomerase II inhibitor etoposide in combination with TRAIL (tumor necrosis factor [TNF]-related apoptosis-inducing ligand) induces a synergistic apoptotic response. The mechanism of the synergistic effect results from the etoposide-mediated increase in the expression of the death receptors 4 (DR4) and 5 (DR5). Inhibition of NF-κB activation by expression of kinase-inactive MEK kinase 1(MEKK1) or dominant-negative IκB (ΔIκB) blocked the increase in DR4 and DR5 expression following etoposide treatment. Addition of a soluble decoy DR4 fusion protein (DR4:Fc) to cell cultures reduced the amount of etoposide-induced apoptosis in a dose-dependent manner. The addition of a soluble TNF decoy receptor (TNFR:Fc) was without effect, demonstrating the specificity of DR4 binding ligands in the etoposide-induced apoptosis response. Thus, genotoxin treatment in combination with TRAIL is an effective inducer of epithelial-cell-derived tumor cell apoptosis relative to either treatment alone.


2015 ◽  
Vol 35 (5) ◽  
pp. 1821-1830 ◽  
Author(s):  
Jianzhong Xi ◽  
Miyong Yun ◽  
Duckgue Lee ◽  
Moon-Nyeo Park ◽  
Eun-Ok Kim ◽  
...  

Background/Aims: Our group reported that cinnamaldehyde derivative, (E)-4-((2-(3-oxopop-1-enyl)phenoxy)methyl)pyridinium malonic acid (CB-PIC) induced apoptosis in hypoxic SW620 colorectal cancer cells via activation of AMP-activated protein kinase (AMPK) and extracellular signal regulated kinase (ERK). Herein, sensitizing effect of CB-PIC was investigated in resistant cancer cells such as paclitaxel (PT) resistant lung cancer cells (H460/PT), and Adriamycin (Adr) resistant breast cancer (MCF7/Adr) and colon cancer (HCT15/cos) cells. Methods: Various drug resistant cell lines were treated with CB-PIC, and the signalling pathway and functional assay were explored by Western blot, Rhodamine assay, FACS, RT-PCR and MTT assay. Results: We found that CB-PIC effectively exerted cytotoxicity, increased sub G1 population and the cleaved form of poly (ADP-ribose) polymerase (PARP) and caspase 9 in drug resistant cancer cells. Furthermore, CB-PIC sensitized resistant cancer cells to adriamycin via downregulation of survival proteins such as survivin, Bcl-xL and Bcl-2, along with MDR1 suppression leading to accumulation of drug in the intracellular region. Of note, CB-PIC transcriptionally decreased MDR1 expression via suppression of STAT3 and AKT signalling in three resistant cancer cells with highly expressed P-glycoprotein. Nonetheless, CB-PIC did not affect transport activity of P-glycoprotein in a short time efflux assay, while epigallocatechin gallate (EGCG) accumulated Rhodamine 123 into intracellular region of cell by direct inhibition of MDR1 transport activity. Conclusions: These data demonstrate that CB-PIC suppresses the P-glycoprotein expression through inhibition of STAT3 and AKT signalling to overcome drug resistance in chemo-resistant cancer cells as a potent chemotherapeutic sensitizer.


2021 ◽  
Author(s):  
Pengjun Zhou ◽  
Xiaoping Wang ◽  
Ziyao Li ◽  
Yifei Wang ◽  
Rong Zhang

Abstract Chemotherapy is one of the effective ways to treat esophageal squamous cell carcinoma (ESCC), but the development of chemoresistance during chemotherapy lowers drug efficacy. Although previous studies have shown that the ribosomal protein S15A (RPS15A) involved in the progression and overall survival of malignancies, its function in chemoresistance is unknown. This study sought to elucidate the function of RPS15A in chemoresistance in ESCC. Our results show that knocking down or overexpressing RPS15A in ESCC cell lines can significantly change the sensitivity of chemotherapeutic drugs and affect cisplatin-induced apoptosis. Moreover, an increase in chemotherapeutic drug concentration leads to increased expression of RPS15A and CD44 proteins. When we utilized the ESCC cisplatin-resistant cell line to corroborate our findings, we found that the levels of RPS15A and CD44 proteins were substantially greater in daughter than parental cells. Subsequent experiments indicated that RPS15A modulated chemoresistance by controlling the expression of CD44 and the cell stemness in ESCC. Hence, our data suggest that RPS15A participates in the chemoresistance in ESCC by controlling the expression of CD44 and regulating cell stemness. Taken together, our study provides plausible mechanisms for RPS15A-mediated chemoresistance in ESCC cells and suggests that the inhibition of the RPS15A/CD44 pathway may be a potential target for improving chemotherapy efficacy.


Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1860
Author(s):  
Sören Arlt ◽  
Vladana Petković ◽  
Gerd Ludwig ◽  
Thomas Eichhorn ◽  
Heinrich Lang ◽  
...  

Neutral [Ru(η6-arene)Cl2{Ph2P(CH2)3SPh-κP}] (arene = benzene, indane, 1,2,3,4-tetrahydronaphthalene: 2a, 2c and 2d) and cationic [Ru(η6-arene)Cl(Ph2P(CH2)3SPh-κP,κS)]X complexes (arene = mesitylene, 1,4-dihydronaphthalene; X = Cl: 3b, 3e; arene = benzene, mesitylene, indane, 1,2,3,4-tetrahydronaphthalene, and 1,4-dihydronaphthalene; X = PF6: 4a–4e) complexes were prepared and characterized by elemental analysis, IR, 1H, 13C and 31P NMR spectroscopy and also by single-crystal X-ray diffraction analyses. The stability of the complexes has been investigated in DMSO. Complexes have been assessed for their cytotoxic activity against 518A2, 8505C, A253, MCF-7 and SW480 cell lines. Generally, complexes exhibited activity in the lower micromolar range; moreover, they are found to be more active than cisplatin. For the most active ruthenium(II) complex, 4b, bearing mesitylene as ligand, the mechanism of action against 8505C cisplatin resistant cell line was determined. Complex 4b induced apoptosis accompanied by caspase activation.


2000 ◽  
Vol 113 (16) ◽  
pp. 2845-2854
Author(s):  
Z. Dastoor ◽  
J. Dreyer

Recent evidence has shown a role for the heat shock cognate protein Hsc70 in the response to oxidative stress. We have investigated the subcellular distribution of Hsc70 by means of laser scanning confocal microscopy in neuroblastoma NB41A3 cells, in fibroblasts R6 cells and in R6-Bcl-2, an apoptosis-resistant cell line, and its function in oxidative stress and in apoptosis has been evaluated. Endogenous Hsc70 is localised predominantly in the cytoplasm in unstressed cells, whereas oxidative stress but not apoptosis induces its translocation into the nucleus. In transfected cells overexpressing Hsc70 increased nuclear translocation and aggregation of Hsc70 in intracellular speckles is observed after oxidative stress and, to a lesser degree, after exposure to apoptotic agents. Bcl-2 did not influence the movement of Hsc70 nor the formation of Hsc70-containing speckles. Nuclear translocation of Hsc70 can be modulated by the expression of components from a previously described plasma membrane oxidoreductase involved in the cellular response against oxidative stress. Our data may suggest a correlation between differential translocation of Hsc70 with specific functions in apoptosis and a potential role in the protection against reactive oxygen species.


2020 ◽  
Vol 10 ◽  
Author(s):  
Marie-Pierre Courageot ◽  
Laurent Duca ◽  
Laurent Martiny ◽  
Emmanuelle Devarenne-Charpentier ◽  
Hamid Morjani ◽  
...  

It is now admitted that in addition to acquired resistance, the tumor microenvironment contributes to the development of chemo-resistance and malignant progression. In a previous study, we showed that Dox induced apoptosis in FTC-133 cells by trigging JNK pathway. This process was accompanied by a decrease of thrombospondin-1 (TSP-1) expression. Moreover, exogenous TSP-1 or its C-terminal-derived peptide interact with receptor CD47 and are able to protect FTC-133 cells against Dox-induced apoptosis. Here, we investigated the involvement of TSP-1/CD47 interaction in a context of acquired multidrug resistance in FTC-133 cells. To that end, we established a Dox-resistant cell line (FTC-133R cells) which developed a resistance against Dox-induced apoptosis. Cell viability was evaluated by Uptiblue assay, nuclear Dox was measured by microspectrofluorimetry, caspase activity was measured by fluorescence of cleaved caspase-3 substrate, gene expression was evaluated by RT-PCR and protein expression was examined by western-blot. Our results showed that FTC-133R overexpressed the P-gp and were 15-fold resistant to Dox. JNK phosphorylation and Dox-induced apoptosis were reduced in FTC-133R cells. Expression of CD47 was increased in FTC-133R cells but TSP-1 expression presented similar levels in two cell lines. VPL restored Dox nuclear uptake and FTC-133R cell sensitivity to apoptosis and induced a decrease in CD47 mRNA expression. Moreover, knockdown of CD47 in FTC-133R cells induced an increase in JNK activation and sensitized FTC-133R cells to Dox. Our data suggest that CD47 is able to contribute to the protection of FTC-133R cells against Dox-induced apoptosis and/or to potentiate the acquired Dox resistance.


Pancreas ◽  
2003 ◽  
Vol 27 (3) ◽  
pp. 220-224 ◽  
Author(s):  
Akira Togawa ◽  
Hiroshi Ito ◽  
Fumio Kimura ◽  
Hiroaki Shimizu ◽  
Masayuki Ohtsuka ◽  
...  

2006 ◽  
Vol 395 (2) ◽  
pp. 311-318 ◽  
Author(s):  
Alessandro Prinetti ◽  
Danilo Millimaggi ◽  
Sandra D'Ascenzo ◽  
Matilda Clarkson ◽  
Arianna Bettiga ◽  
...  

PTX (Paclitaxel®) is an antimitotic agent used in the treatment of a number of major solid tumours, particularly in breast and ovarian cancer. This study was undertaken to gain insight into the molecular alterations producing PTX resistance in ovarian cancer. PTX treatment is able to induce apoptosis in the human ovarian carcinoma cell line, CABA I. PTX-induced apoptosis in CABA I cells was accompanied by an increase in the cellular Cer (ceramide) levels and a decrease in the sphingomyelin levels, due to the activation of sphingomyelinases. The inhibition of acid sphingomyelinase decreased PTX-induced apoptosis. Under the same experimental conditions, PTX had no effect on Cer and sphingomyelin levels in the stable PTX-resistant ovarian carcinoma cell line, CABA-PTX. The acquisition of the PTX-resistant phenotype is accompanied by unique alterations in the complex sphingolipid pattern found on lipid extraction. In the drug-resistant cell line, the levels of sphingomyelin and neutral glycosphingolipids were unchanged compared with the drug-sensitive cell line. The ganglioside pattern in CABA I cells is more complex compared with that of CABA-PTX cells. Specifically, we found that the total ganglioside content in CABA-PTX cells was approximately half of that in CABA I cells, and GM3 ganglioside content was remarkably higher in the drug-resistant cell line. Taken together our findings indicate that: i) Cer generated by acid sphingomyelinase is involved in PTX-induced apoptosis in ovarian carcinoma cells, and PTX-resistant cells are characterized by their lack of increased Cer upon drug treatment, ii) PTX resistance might be correlated with an alteration in metabolic Cer patterns specifically affecting cellular ganglioside composition.


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