Author’s response to reviews
Title: Patients with hepatic breast cancer metastases demonstrate highly specific profiles of
matrix metalloproteinases MMP-2 and MMP-9 after SIRT treatment as compared to other prima
y and secondary liver tumours
Authors:
Olga Golubnitschaja (olga.golubnitschaja@ukb.uni-bonn.de)
Kristina Yeghiazaryan (kristina.yeghiazaryan@ukb.uni-bonn.de)
Helena Stricker (helena.stricker@t-online.de)
Daniela Trog (daniela.trog@gmx.de)
Hans Schild (schild@uni-bonn.de)
Leonard Berliner (leonardb23@aol.com)
Version: 1 Date: 10 Mar 2016
Author’s response to reviews:
Reviewer 1: The authors highly appreciate the overall comments and recommendations of the
expert. In particular, we are very glad to know that our findings have been found interesting and
valuable.
Further, we are glad to provide below summarized responses to the individual points listed in the
report.
1. The authors should explain why they pick up MMP-2 and -9 although MMP-2 and -9 are
implicated in cancer metastasis, while not others. It will be nice if the authors could also test the
expression levels/activities of the other MMPs, which on one hand will provide a more complete
picture of MMPs family profiles in hepatic breast cancer metastasis, on the other hand, would
prove the specificity of changing of MMP-2 and -9.
The authors highly appreciate the recommendation to make the choice of the molecular targets
clearer for the readers. Indeed, our working hypothesis focused on both gelatinases A and B
(MMP-2 and -9, respectively), due to their specific role which has been clearly demonstrated by
number of studies for tumour development/progression and metastatic disease. Corresponding
paragraph (marked in red colour) is included into the revised version of the manuscript now (see
“Background” pages 5-6).
In contrast, it was not the purpose of the current project to test the whole spectrum of
metalloproteinases as potential target-candidates, since according to the project’s philosophy, an
application of each target should be properly justified considering its individual function in the
relevant (patho)mechanisms. Corresponding hypothesis should be, further, created for this kind
of additional experiments. This is also an issue for the project-relevant ethical considerations.
Concretely, the responsible Ethical Commission of the University of Bonn, where the
experiments have been effectively performed, requires clear justification for any measurement to
be performed utilising human samples, in order to approve the project’s performance.
Contextually, the “protein family of proteases degrading the ECM” is not considered as targeted
enough to satisfy the ethical considerations of the research project.
2.In the current manuscript, the authors only use one assay to test the MMP-2 and -9, it would be
more convincing if the authors can combine another assay such as ELISA to further confirm at
least one time point of MMP2 and -9 levels in the serum samples.
To this end, we would like to make a note that the patterns of activities of both MMP-2 and -9
are regulated by many molecular mechanisms applied via a cascade of individual steps including
transcription, translation, several events of post-translational modification and, finally, MMPactivity inhibition by TIMPs. In this comprehensive situation, it is very difficult to expect a
linear correlation between expression rates (e.g. measured by ELISA) and levels of activity
(Zymography used in the project). From the entire regulation cascade, the “end-product”, namely
effective activity levels of both molecular targets have the highest relevance for biological
aspects of the processes and their clinical utility. This paragraph is included into the revised
manuscript now, in order to make the experimental design clearer for the readers (see
“Background” pages 5-6).
3.Could the up-regulation of MMP-2 and -9 after SIRT treatment shows any correlation with
patient outcome?
This is a very good question planned to be clarified during the extended future project.
4.The data should be reorganized to be more neat and clear. It is not suggested that one figure is
separated into different parts.
Certainly, the issue is very important, since the diagrams are crucial for the understanding of the
“Results”! However, the form of the figure presentation depends very much on the final version
of the paper design, which the journal may propose us at the stage of production. Since we fully
trust in the excellent capacity of “BMC Cancer” to support the most appropriate presentation of
our highly comprehensive diagrams, would consult the issue with the journal’s production team
accordingly.
5.There are some typos in the manuscripts. Page 5, line 83, resent publications should be
recent….; page 15, line 286, dies not should be does not.
The spelling has been corrected correspondingly.
6.Suggesting the authors shorten the discussion part.
The authors have thoroughly analysed the suggestion to shorten the “Discussion”. However, a
consensus has been built that current version reflects field’s related challenges in the most
optimal way contextually placing the reported findings, in order to support better understanding
the key-messages of the current paper.