Chuanpit Ninsontia,Varisa Pongrakhananon,Chatchai Chaotham, Pithi Chanvorachote

Cell-based Drug and Health Products Development Research Unit,Faculty of Pharmaceutical Sciences, Chulalongkorn University,Bangkok,Thailand

Ouabain inhibits anchorage-independent growth in human lung cancer cells via integrin αvβ3 reduction

Chuanpit Ninsontia,Varisa Pongrakhananon,Chatchai Chaotham, Pithi Chanvorachote*

Cell-based Drug and Health Products Development Research Unit,Faculty of Pharmaceutical Sciences, Chulalongkorn University,Bangkok,Thailand

A R T I C L E I N F O

Article history:

Available online 25 November 2015

Ouabain

Anchorage-independent growth

Lung cancer cells

Integrin αvβ3reduction

Physiological effects of ouabain(Fig.1A),a human endogenous hormone,have been intensively investigated nowadays. Recent studies demonstrate anticancer activity of ouabain in sensitization of apoptosis and suppression of migration in lung cancer cells[1,2].Focusing on metastatic process,the ability of cancer cells to grow in an anchorage-independent condition determines the success of cancer metastasis[3]. Thus,this study aimed to evaluate the effect of ouabain on anchorage-independent growth in human lung cancer cells.

The proliferative effect of physiological concentrations of ouabain in human lung cancer H460 cells was frstly evaluated.H460 cells were cultured in the absence or presence of ouabain(5–20 pM)for various time points.Cell viability was determined by the MTT assay at 24,48 and 72 h,respectively. The results show that treatment with ouabain at concentrations ranging from 2.5 to 20 pM caused no alteration on proliferation of H460 cells at 24 and 48 h,while 10 and 20 pM of ouabain signifcantly inhibited such effect at 72 h(Fig.1B). Soft agar colony formation assay reveals that the colony size was reduced in response to ouabain treatment(Fig.1C).Meanwhile,there was no signifcant difference in terms of colony number,suggesting that the effect of ouabain against an anchorage-independent growth mainly caused the inhibition of cell growth without changing cell survival.Since integrin αvβ3was shown to potentiate metastasis,our data also demonstrated that ouabain was able to suppress the anchorageindependent growth through the inhibition of integrin αvβ3expressions.This fnding may help fulfll the knowledge regarding the role of ouabain in the regulation of cancer behaviorsand encourage the development of this compound against cancer metastasis.

Fig.1–Structure of ouabain(A),Cell proliferation(B),Anchorage-independent growth(C),and Anchorage-independent growth regulatory proteins(D).

Acknowledgements

This research has been supported by The Thailand Research Fund through The Royal Golden Jubilee Ph.D.program(Grant No.PHD/0004/2556)andThe Ratchadaphiseksomphot Endowment Fund 2013 of Chulalongkorn University(CU-56-384-HR).

R E F E R E N C E S

[1]Chanvorachote P,Pongrakhananon V.Ouabain downregulates Mcl-1 and sensitizes lung cancer cells to TRAIL-induced apoptosis.Am J Physiol Cell Physiol 2013;304(3):C263–C272.

[2]Pongrakhananon V,Chunhacha P,Chanvorachote P.Ouabain suppresses the migratory behavior of lung cancer cells.PLoS ONE 2013;8(7):e68623.

[3]Desgrosellier JS,Barnes LA,Shields DJ,et al.Integrin αvβ3/csrc“oncogenic unit”promotes anchorage-independence and tumor progression.Nat Med 2009;15(10):1163–1169.

*E-mail address:pithi_chan@yahoo.com.

Peer review under responsibility of Shenyang Pharmaceutical University.

http://dx.doi.org/10.1016/j.ajps.2015.11.043

1818-0876/?2016 Production and hosting by Elsevier B.V.on behalf of Shenyang Pharmaceutical University.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).