Auto-antibodies to β-F1-ATPase and vimentin in malignant mesothelioma

Our plain-English summary of Auto-antibodies to β-F1-ATPase and vimentin in malignant mesothelioma, by J. Creaney, I.M. Dick, D. Yeoman, et al (PloS One, 2011).

The study

• Authors: J. Creaney, I.M. Dick, D. Yeoman, S. Wong, B.W. Robinson
• Journal: PloS One
• Published: 2011;6(10):e26515
• Cited by: 14 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Patients with Malignant Mesothelioma (MM) develop unidentified auto-antibodies to MM tumour antigens. This study was conducted to identify the targets of MM patient auto-antibodies in order to try to understand more of the anti-tumour response and to determine if these antibodies might be helpful for diagnosis or prognostication. Using MM patient sera in a Western immunoblott screening strategy, no common immunoreactive proteins were identified. The sera from one long-term survivor recognised a protein band of 50-60 kDa present in cell lysates from four of five MM cell lines tested. The immunoreactive proteins in this band were identified by 2D electrophoretic separation of a MM cell line protein lysate, followed by analysis of excised immunoreactive proteins on a MALDI TOF mass spectrometer and peptide mass fingerprinting. The immunoreactive proteins identified were vimentin (accession gi55977767) and the ATP synthase (F1-ATPase) beta chain (accession gi114549 and gi47606749). ELISA assays were developed for antibodies to these proteins. Neither vimentin (median and 95% CI 0.346; 0.32-0.468 for MM patients, 0.327; 0.308-0.428 for controls) nor ß-F1-ATPase (0.257; 0.221-0.453 for MM patients, 0.263; 0.22-0.35 for controls) showed significant differences in autoantibody levels between a group of MM patients and controls. Using a dichotomized antibody level (high, low) for these targets we demonstrated that vimentin antibody levels were not associated with survival. In contrast, high ß-F1-ATPase antibody levels were significantly associated with increased median survival (18 months) compared to low ß F1 ATPase antibody levels (9 months; p = 0.049). Immunohistochemical analysis on a MM tissue microarray showed cytoplasmic staining in 28 of 33 samples for vimentin and strong cytoplasmic staining in14 and weak in 16 samples for ß-F1-ATPase. Therefore antibodies to neither vimentin nor ß-F1-ATPase are useful for differential diagnosis of MM, however high antibody levels to ß-F1-ATPase may be associated with increased survival and this warrants further investigation.

In plain English

This was a laboratory study from Western Australia that looked for antibodies mesothelioma patients make against proteins in their own tumours. The authors tested blood serum from approximately 150 malignant mesothelioma (MM) patients, collected within two months of diagnosis, against proteins from mesothelioma cell lines. They found no antibody reaction common to the patients. Serum from one patient strongly recognised proteins later identified as vimentin and the beta chain of ATP synthase (beta-F1-ATPase). This patient was a 73-year-old woman with pleural epithelial MM who was alive 45 months after diagnosis. In a smaller group (22 MM patients and 20 controls in the article's table), antibody levels to neither protein differed significantly between patients and controls. Patients with beta-F1-ATPase antibody levels above the median had a median survival of 18 months, against 9 months for those below it (p = 0.049). Vimentin antibody levels showed no survival advantage. Both proteins were detected in many mesothelioma tissue samples. The authors concluded that neither antibody was useful for differential diagnosis, but that high beta-F1-ATPase antibody levels may be associated with longer survival and warrant further investigation.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory study: Western immunoblotting of patient sera, protein identification by 2D electrophoresis and mass spectrometry, ELISA antibody measurement in patients and controls with survival analysis, and immunohistochemistry on tumour tissue and effusions
• Who was studied: About 150 malignant mesothelioma patients (sera taken within two months of diagnosis) from Sir Charles Gairdner Hospital and Hollywood Specialist Centre, Perth, Western Australia, screened by immunoblot. The ELISA group in Table 1 was 11 short-term survivors (under 12 months) and 11 long-term survivors (over 12 months) with MM, plus 20 controls described as healthy laboratory volunteers. The index patient (#145) was a 73-year-old woman with pleural epithelial MM.
• Exposure: Asbestos exposure was not analysed. The study measured serum antibody levels to vimentin and beta-F1-ATPase. Table 1 lists asbestos exposure history: short-term survivors 7 yes, 4 unknown; long-term survivors 8 yes, 3 unknown; controls 1 yes, 8 no, 11 unknown.
• Main results:
  • Western immunoblotting showed no antibody reactivity common to the MM patients.
  • Serum from one patient (#145, a 73-year-old woman with pleural epithelial MM) showed strong reactivity to protein(s) of 50 to 60 kDa. Mass spectrometry identified these as vimentin and the mitochondrial ATP synthase beta chain.
  • Anti-vimentin antibody levels, excluding one control with high levels: MM patients had a median of 0.346 (95% CI 0.32 to 0.468) and controls 0.327 (0.308 to 0.428). The difference was not statistically significant. Two MM patients, including the index patient, were above the control-defined threshold.
  • Anti-beta-F1-ATPase antibody levels: MM patients had a median of 0.257 (95% CI 0.221 to 0.453) and controls 0.263 (0.22 to 0.35). There was no significant difference. Four patients were more than 2 standard deviations above the control mean.
  • MM patients with anti-beta-F1-ATPase levels above the median had a median survival of 18 months. Those with low levels had a median survival of 9 months (p = 0.049).
  • No survival advantage was found when MM patients were split into high or low anti-vimentin antibody levels.
  • Vimentin in tissue: of 34 MM tissues, 24 stained intensely positive, 4 weakly or equivocally, and 6 were negative. Vimentin in effusions: of 24 MM effusions, 19 were positive, 1 weakly stained and 4 negative.
  • Beta-F1-ATPase in tissue: of 34 MM tissues, 14 stained positive, 16 weakly or equivocally, and 4 were negative. Beta-F1-ATPase in effusions: of 21 MM effusions, 14 were weakly positive and 7 negative.
• The authors' conclusion: The authors concluded that antibodies to neither vimentin nor beta-F1-ATPase are useful for differential diagnosis of MM. They also concluded that high beta-F1-ATPase antibody levels may be associated with increased survival, which warrants further investigation.
• Limitations the authors state:
  • The autoimmune status of the MM patients, which may have contributed to anti-vimentin antibody production, was not known.
  • The authors noted that the identification of antibodies to vimentin may have been an epiphenomenon.
  • Validation experiments did not confirm the reactivity. The index patient's serum did not recognise recombinant vimentin or the recombinant beta-F1-ATPase fragment on Western immunoblotting. The authors attributed this to denaturing conditions.
  • It was unclear whether strong beta-F1-ATPase staining in macrophages reflected the macrophages' own mitochondria or material they had engulfed.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Median Overall Survival, Differential Diagnosis.

Related studies

• p53 autoantibodies in patients with malignant mesothelioma: stability through disease progression — J. Creaney, B.M. McLaren, et al. (2001)
• The distribution of vimentin and keratin in epithelial and nonepithelial neoplasms. A comprehensive immunohistochemical study on formalin- and alcohol-fixed tumors — N. Azumi, H. Battifora (1987)
• Vimentin regulates activation of the NLRP3 inflammasome — G. dos Santos, M.R. Rogel, et al. (2015)
• Immunohistochemical staining for vimentin and keratin in malignant mesothelioma — A. Churg (1985)
• Unusual primary lung neoplasms: spindle cell and undifferentiated lung carcinomas expressing only vimentin — S.P. Hammar, K.O. Hallman (1990)
• Gender comparisons in human lung cancer: analysis of p53 mutations, anti-p53 serum antibodies and C-erbB-2 expression — D.G. Guinee, W.D. Travis, et al. (1995)

Browse more research in PloS One, or return to medical research.