Differential expression of p52 and RelB proteins in the metastatic and non-metastatic groups of uveal melanoma with patient outcome
Authors: Lata Singh
Neeru Saini
Neelam Pushker
Kunzang Chosdol
Rachna Meel
Sameer Bakhshi
Seema Kashyap
Seema Sen
Mithalesh Kumar Singh
Journal: Journal of Cancer Research and Clinical Oncology (2019)
Discipline: CLINICAL MEDICINE
Keywords: Co-expression; Metastasis; RelB; Uveal melanoma; p52.
Affiliations: Department of Ocular Pathology, Dr. R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India., Department of Biosciences, JMI, New Delhi, India., Department of Biochemistry, AIIMS, New Delhi, India., Department of Ophthalmology, Dr. R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India., Functional Genomics Unit, Institute of Genomics and Integrative Biology, New Delhi, India., Department of Medical Oncology, IRCH, AIIMS, New Delhi, India., Department of Ocular Pathology, Dr. R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. .

Abstract:  Purpose: Non-canonical NFκB (NC-NFκB) pathway plays an influential role in metastasis, which promotes cancer proliferation and progression. The aim of the study was to examine the expression of NC-NFκB proteins and their correlation with clinicopathological factors associated with metastatic cases of uveal melanoma (UM) and with the patient outcome. Method: Expression of NC-NFκB proteins (p52, RelB, and co-expression of p52/RelB) was evaluated in 75 formalin-fixed cases of uveal melanoma by immunohistochemistry. Validation of nuclear immunoreactivity was done by western blotting. Transcriptional status of NC-NFκB genes was assessed in 60 fresh tumor tissues by quantitative real-time PCR. Co-immunoprecipitation was performed to determine the presence of native p52/RelB heterodimer in UM. Prognostic relevance was determined using Cox proportional hazard and Kaplan-Meier methods. Results: Immunohistochemical expression of p52, RelB, and their co-expression was observed in 81%, 68.7%, 56.2% of metastatic cases, respectively, while their expression was seen only in 38%, 33% and 30% of non-metastatic cases. Loss of BAP-1 was correlated with expression of p52 and RelB proteins. Co-immunoprecipitation assay confirmed the putative interaction of p52 with RelB protein in metastatic cases of uveal melanoma. Co-expression of p52/RelB and expression of p52 protein was significantly correlated with decreased metastasis-free survival (MFS) (p = 0.004; p = 0.002) and overall survival (OS) (p = 0.004; p = 0.032), while the RelB expression only correlated with reduced MFS (p = 0.003). Conclusion: Our data showed that non-canonical NFκB proteins were significantly higher in metastatic cases and associated with poor outcome of the patients. Furthermore, the p52 protein could be used as a potential therapeutic biomarker for metastatic cases in uveal melanoma. 

Retracted: No

PubPeer comments:
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 #1 Dear Anonymous Commenter, Thank you for your comment. We have used the same normal choroid section to show the expression of p52 and RelB protein in immunohistochemistry (IHC). As a result, they look alike in the image because they both are the same formalin-fixed sections that are used for different proteins in IHC. , 
 #3 Dear Commenter, Thank you so much for this observation. We didn t know that we have to declare the spliced band also. We ran one metastatic sample in other blot and other 3 samples in another blot. This experiment was performed only on representative samples. This will not affect the results of this paper. We will definitely declare the spliced band in future manuscripts. Thank you for this information. Thanks , 
 #2 #1 Dear Anonymous Commenter, Thank you so much for pointing out this image. While looking into our raw data, we found the unconscious error during the revised figure preparation. The correct image is showing below. This will not alter the main outcome of our results. While we are sorry for the same and also it may be noted that the primary findings published in the manuscript remain unchanged. We will be more careful in the future. Thanks [file] ,