The MEK1/2 Inhibitor AZD6244 Sensitizes BRAF-Mutant Thyroid Cancer to Vemurafenib
Authors: Jinna Zhang
Kejun Zhang
Xuelong Jiao
Liang Ning
Honglai Zhang
Hao Song
Dong Chen
Journal: Medical Science Monitor (2018)
Discipline: CLINICAL MEDICINE
Keywords: MAP Kinase Signaling System; Proto-Oncogene Proteins B-raf; Thyroid Neoplasms.
Affiliations: Department of Radiotherapy, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China (mainland)., Department of Thyroid Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China (mainland)., Department of General Surgery, The Affiliated Hospital of Qingdao University, Qingdao, Shandong, China (mainland).

Abstract:  BACKGROUND [i]BRAF[/i]V600E mutation occurs in approximately 45% of papillary thyroid cancer (PTC) cases, and 25% of anaplastic thyroid cancer (ATC) cases. Vemurafenib/PLX4032, a selective BRAF inhibitor, suppresses extracellular signal-regulated kinase kinase/extracellular signal-regulated kinase 1/2 (MEK/ERK1/2) signaling and shows beneficial effects in patients with metastatic melanoma harboring the [i]BRAFV600E[/i] mutation. However, the response to vemurafenib is limited in BRAF-mutant thyroid cancer. The present study evaluated the effect of vemurafenib in combination with the selective MEK1/2 inhibitor AZD6244 on cell survival and explored the mechanism underlying the combined effect of vemurafenib and AZD6244 on thyroid cancer cells harboring BRAFV600E. MATERIAL AND METHODS Thyroid cancer 8505C and BCPAP cells harboring the [i]BRAFV600E[/i] mutation were exposed to vemurafenib (0.01, 0.1, and 1 ¬µM) and AZD6244 (0.01, 0.1, and 1 ¬µM) alone or in the indicated combinations for the indicated times. Cell viability was detected by the MTT assay. Cell cycle distribution and induction of apoptosis were detected by flow cytometry. The expression of cyclin D1, P27, (P)-ERK1/2 was evaluated by Western blotting. The effect of vemurafenib or AZD6244 or their combination on the growth of 8505C cells was examined in orthotopic xenograft mouse models [i]in vivo[/i]. RESULTS Vemurafenib alone did not increase cell apoptosis, whereas it decreased cell viability by promoting cell cycle arrest in BCPAP and 8505C cells. AZD6244 alone increased cell apoptosis by inducing cell cycle arrest in BCPAP and 8505C cells. Combination treatment with AZD6244 and vemurafenib significantly decreased cell viability and increased apoptosis in both BCPAP and 8505C cells compared with the effects of each drug alone. AZD6244 alone abolished phospho-ERK1/2 (pERK1/2) expression at 48 h, whereas vemurafenib alone downregulated pERK1/2 at 4-6 h, with rapid recovery of expression, reaching the highest level at 24-48 h. Combined treatment for 48 h completely inhibited pERK1/2 expression. Combination treatment with vemurafenib and AZD6244 inhibited cell growth and induced apoptosis by causing cell-cycle arrest, with the corresponding changes in the expression of the cell cycle regulators p27Kip1 and cyclin D1. Co-administration of vemurafenib and AZD6244 [i]in vivo[/i] had a significant synergistic antitumor effect in a nude mouse model. CONCLUSIONS Vemurafenib activated pERK1/2 and induced vemurafenib resistance in thyroid cancer cells. Combination treatment with vemurafenib and AZD6244 inhibited ERK signaling and caused cell cycle arrest, resulting in cell growth inhibition. Combination treatment in patients with thyroid cancer harboring the [i]BRAFV600E[/i] mutation may overcome vemurafenib resistance and enhance the therapeutic effect. 

Retracted: Yes

PubPeer comments:
 Retraction, March 7 2022, found here: https: www.medscimonit.com abstract full idArt 936571  This publication has been retracted by the Editor due to the identification of falsified figure images and manuscript content that raise concerns regarding the credibility of the study and the manuscript. , 
 Dear sir, Who tell you the falsified figure images and manuscript content that raise concerns regarding the credibility of the study and the manuscript? It was our author who requested the retraction, not the journal . Why doesn t your system display the questions raised by the author? You should show our authors own reasons for retracting the manuscript. Some experimental results cannot be repeated by us, which is the main reason for our retraction. Thanks , 
 #2 Dr. Chen: It sounds as if you have comments or concerns about the retraction that should be directed to the editors of the journal. I just confirmed that the text of the retraction notice is exactly as quoted above by Dr. Bik. , 
 Dear sir, It is our own request to retract the article.This is the notice given by theJournal Dear Author, We are pleased to notify you that your manuscript #936571 titled  Retracted: The MEK1 2 Inhibitor AZD6244 Sensitizes BRAF-Mutant Thyroid Cancer to Vemurafenib , has now been published online . , 
 #4 Thank you for clarifying that the authors requested the retraction. If you feel the retraction notice does not make that clear, you should contact the journal. This website is not affiliated with the journal. , 
 In a recent study of chemosensitivity of cells, we found that different cells or cell extracts were reversed and thus repeated experiments were inconsistent. The 8505C cells we used were probably SW1736. Further detection of pERK in 8505C cells showed that 8505C cells contained poor endogenous pERK, and repeated experiments could not be established. We repeated the experiment of 8505C with SW1736, and the experimental results were consistent with 8505C. We therefore reasoned that the cells might be confused. The cell cycle test is carried out by a third-party institution, which does not explain the abnormality of the test results. There is a high chance that the cells are making mistakes, and it may also be related to cell contamination. For the above reasons, we request the retraction of this article. , 
 Agreed, it s the editors that said they retracted it and they did so because of  the identification of falsified figure images and manuscript content that raise concerns regarding the credibility of the study and the manuscript . It s their words in the abstract, so if you are upset with the wording, speak to the journal, because that was what was published. , 
 In a recent study of chemosensitivity of cells, we found that different cells or cell extracts were reversed and thus repeated experiments were inconsistent. The 8505C cells we used were probably SW1736 cells. Further detection of pERK in 8505C cells showed that 8505C cells contained poor endogenous pERK, and repeated experiments could not be established. We repeated the experiment of 8505C with SW1736, and the experimental results were consistent with 8505C. We therefore reasoned that the cells might be confused. The cell cycle test is carried out by a third-party institution, which does not explain the abnormality of the test results. There is a high chance that the cells are making mistakes, and it may also be related to cell contamination. For the above reasons, we request the retraction of this article. , 
 Dear sir, I am very sorry for the negative impact on you due to the retraction of the manuscript. There must be a misunderstandinguff0cHere s how things gouff1a 1. I stumbled across this information by browsing the pubpeer website on my mobile phone, and I didn t find which reader posted it, nor did I see Dr. Bik s comment. I thought it was the journal Medical Science Monitor. 2.Since I have not received the correction information for the retracted article, I do not know that the journal has retract the article, and I do not know that the pubpeer website and the journal retraction information are linked to each other. So I communicated with the Journal: why was the author not notified of the retraction issue? The retraction content was inconsistent with the author s retraction content.Therefore, I made the above reply to the Journal. 3.I then pasted the journal s information on the pubpeer website.I thought it was the Journal themself published the information on pubpeer. When I replied to the comment, the author s name was partly displayed with  pinyin of the Chinese name. Anyway, it is not Dr. Bik, and I forgot the details. 4 Later, I pasted the content of the exchange with the Journal on pubpeer. I forgot which day we asked the Journal to retract the article. This is our comment to the Journal:  In a recent study of chemosensitivity of cells, we found that different cells or cell extracts were reversed and thus repeated experiments were inconsistent. The 8505C cells we used were probably SW1736. Further detection of pERK in 8505C cells showed that 8505C cells contained poor endogenous pERK, and repeated experiments could not be established. We repeated the experiment of 8505C with SW1736, and the experimental results were consistent with 8505C. We therefore reasoned that the cells might be confused. The cell cycle test is carried out by a third-party institution, which does not explain the abnormality of the test results. There is a high chance that the cells are making mistakes, and it may also be related to cell contamination. For the above reasons, we request the retraction of this article. This is the comment the Journal sent us: Dear Author, We are pleased to notify you that your manuscript #936571 titled  Retracted: The MEK1 2 Inhibitor AZD6244 Sensitizes BRAF-Mutant Thyroid Cancer to Vemurafenib , has now been published online at https: www.medscimonit.com, along with the following Digital Object Identifier (DOI): #10.12659 MSM.936571 . The article will be forwarded to PubMed nad PubMed Central PMC for archive in their repository. Please note, that their publication process, which is beyond our control, usually takes approximately two weeks. Medical Science Monitor publishes noteworthy articles from all around the world. Please feel free to explore other articles related to your interests at https: www.medscimonit.com. Sincerely yours, Editorial Team Medical Science Monitor , 
 After browsing the website, we found the article retraction and retraction content the identification of falsified figure images and manuscript content that raise concerns regarding the credibility of the study and the manuscript . ,