Bromelain inhibits COX-2 expression by blocking the activation of MAPK regulated NF-kappa B against skin tumor-initiation triggering mitochondrial death pathway
Authors: Jasmine George
Yogeshwer Shukla
Kulpreet Bhui
Sahdeo Prasad
Journal: Cancer letters (2009)
Discipline: CLINICAL MEDICINE
Keywords: Chemoprevention; Bromelain; Anti-inflammatory; Anti-invasive; Anti-metastatic
Affiliations: Proteomics Laboratory, Indian Institute of Toxicology Research (CSIR), P.O. Box 80, M.G. Marg, Lucknow 226 001, India.

Abstract:  Chemoprevention impels the pursuit for either single targeted or cocktail of multi-targeted agents. Bromelain, potential agent in this regard, is a pharmacologically active compound, present in stems and fruits of pineapple (Ananas cosmosus), endowed with anti-inflammatory, anti-invasive and anti-metastatic properties. Herein, we report the anti tumor-initiating effects of bromelain in 2-stage mouse skin tumorigenesis model. Pre-treatment of bromelain resulted in reduction in cumulative number of tumors (CNT) and average number of tumors per mouse. Preventive effect was also comprehended in terms of reduction in tumor volume up to a tune of approximately 65%. Components of the cell signaling pathways, connecting proteins involved in cell death were targeted. Bromelain treatment resulted in upregulation of p53 and Bax and subsequent activation of caspase 3 and caspase 9 with concomitant decrease in Bcl-2. A marked inhibition in cyclooxygenase-2 (Cox-2) expression and inactivation of nuclear factor-kappa B (NF-kappaB) was recorded, as phosphorylation and consequent degradation of I kappa B alpha was blocked by bromelain. Also, bromelain treatment curtailed extracellular signal regulated protein kinase (ERK1/2), p38 mitogen-activated protein kinase (MAPK) and Akt activity. The basis of anti tumor-initiating activity of bromelain was revealed by its time dependent reduction in DNA nick formation and increase in percentage prevention. Thus, modulation of inappropriate cell signaling cascades driven by bromelain is a coherent approach in achieving chemoprevention. 

Retracted: No

PubPeer comments:
 Image recycled between two journals. Same actin for two different treatments. doi:10.1016 j.canlet.2009.03.003, figure 5: Effect of bromelain on the expression of growth regulatory proteins doi:10.1016 j.cbi.2009.05.012 figure 4B: Effect of [6]-gingerol on apoptosis ![file] , 
  Fig. 4. Effect of bromelain on the expression of tumor suppressor, anti-apoptotic and proapoptotic proteins. Western blot analysis of wild type p53, Bax, Bcl-2; procaspases 9,3 and caspases 9,3 proteins in mouse skin tumors. ... i u2013 vehicle control, ii u2013 DMBA + TPA, iii u2013 BR + DMBA + TPA, and iv u2013 BR + ACE + TPA. Beta-actin control is a section of that used in [Kalra et al (2008)] , Fig 3(A). ![file] , 
  Fig. 4. i u2013 vehicle control, ii u2013 DMBA + TPA, iii u2013 BR + DMBA + TPA, and iv u2013 BR + ACE + TPA. Procaspase-9 band: ![file] Please, people, try harder. As noted elsewhere by Narcissus X, the same band appears in [Bhatnagar et al. (2015)] , there identified as  bcl-2 . Could the authors clarify this point? ![] , 
 Delphinium Cuneatum commented, vis-a-vis [Srivastava et al. (2012)] :  Figure 6 (caspase 9 blot) is more similar than one would expect with figure 5 (total ERK1 2) of a previous paper from this group. The same blot with two different exposures appears to have been used after changing the orientation as illustrated below. ![] , 
 Another panel from Figure 5: ![file] I am unable to discern any difference between Lanes i and iv in the IkappaBalpha band. , 
 #2 Curious band patterns. ![file] , 
 *[Above]* The p53 panel of  Fig. 4. Effect of bromelain on the expression of tumor suppressor, anti-apoptotic and proapoptotic proteins. Western blot analysis of wild type p53 . Is it irresponsible to compare the actin lanes to *[below]* Fig 3(A) from  Induction of apoptosis by tea polyphenols mediated through mitochondrial cell death pathway in mouse skin tumors [(Roy et al 2009)] ? ![file] It would be irresponsible not to compare them! , 
 Figure 4 and a panel of Figure 5 [at right]. Unexpected similarities with lanes from [at left] Fig 3 of  Inhibitory effects of tea polyphenols by targeting cyclooxygenase-2 through regulation of nuclear factor kappa B, Akt and p53 in rat mammary tumors [(Roy et al 2011)] . ![file]  Fig. 3 Western blots showing the effect of GTP and BTP on a NF-kB, b Akt, c Cox-2, d Wild type- p53, e Mutant- p53 and f u03b2-actin in mouse mammary tumors in different groups. Lanes: (a) Control, (b) (0.1%) GTP, (c) (0.1%) BTP, (d) DMBA, (e) (0.1%) GTP + DMBA, (f) (0.1%) BTP + DMBA. , 
 Here are [below] some panels from Figures 3 and 4, for comparison with [above] Bax and p53 panels from Figure 3 of  Regulation of p53, nuclear factor kappaB and cyclooxygenase-2 expression by bromelain through targeting mitogen-activated protein kinase pathway in mouse skin [(Kalra et al 2008)] : ![] Again: [below] some panels from Figs 3 and 4 (without the loading controls this time), for comparison with [above] the Bcl-2 and Activated Caspase panels of FIg 3 from Kalra et al (2008). ![] , 
 #8 For clarity, the lower panels in comment #2 ( p53 wild and matching control) were taken from Fig 3(A) of Kalra et al (2008) for comparison. https: pubpeer.com publications 4197501DBC472982247DE0AFA234E3#12 , 
 Corrigendum issued 6 February 2020: https: www.sciencedirect.com science article pii S0304383520300252  The authors regret to inform that there were unintentional errors in figures 4 and 5. The corrected figures are given below. This does not impact the scientific conclusion of the manuscript. The authors would like to apologies for any inconvenience caused. ![] It is not clear whether this is intended to replace Fig 4 or 5. Could the authors correct the correction? , 
 #11 u201cIt is not clear whether this is intended to replace Fig 4 or 5. Could the authors correct the correction?u201d As the authenticity of these figures does not u201cimpact the scientific conclusion of the manuscript,u201d does it really matter? ,