Review for 10.1186/1471-230X-12-34 (2012)

Reviewer's report
Title:Gastric cancer cell supernatant causes apoptosis and fibrosis in the
peritoneal tissues and results in an environment favorable to peritoneal
metastases, in vitro and in vivo
Version: 3Date:21 December 2011
Reviewer: Masakazu Yashiro
Reviewer's report:
The study by Na and colleagues investigates the effect of soluble factors
secreted by gastric carcinoma cells on morphology and apoptosis of peritoneal
mesothelial cells. Serum free conditioned media (SF-CM) from gastric carcinoma
cells induced the morphological change and apoptosis bodies in transmission
electron microscopy. In vitro study, SF-CM treatment caused the increased
cytotoxicity of human peritoneal mesothelial cells. SF-CM also promoted the
apoptosis, which was closely correlated with Bcl-2, Bax, caspase-3 and
caspase-8. In vivo study, after SF-CM inoculation into peritoneal cavity,
mesothelial fibrosis and submesothelial extracellular matrix products were
induced.
The findings presented in this study are potentially interesting, but there are
several concerns that impact the validity of the conclusions. Several changes
should be done to make it clearer and some additional data should be presented.
Major comments:
1. The main criticizm is the results of morphological evaluation, including electron
microscopy in the Results Section. The author described that they prepared
several SF-CM from gastric carcinoma cell lines in the Methods, only the
phenomenon of one cell line was shown in this manuscript. To really substantiate
their claims, in study shown in Figure 1and 2, at least one more gastric cancer
cell line should be examined for confirming the responses to soluble factors are
common in gastric cancer cells.
2. The purpose to do the MTT assay shown in Figure 3A is unclear. There was
no describing data indicating the cytotoxicity in the cells treated with SF-CM.
Thus the authors should show the necessity to examine the cytotoxic effect of
SF-CM. Otherwise, these data should be eliminated.
3. The order of section is not in accordance with “Instruction for authors”.
Minor comments:
Background
Page 4 Line 2; It would be better to reword as follows: "Peritoneal metastasis
results in a metastatic cascade”.
Page 4 Line 23; It would be better to add the sentences as follows: "morphology
and biological activity of peritoneal mesothelial cells-”.
Methods
Page 5 Line 19: reduce the space.
Results
Page 9 Lines 14-16:Figure 4A is low resolution. The image showing stromal
components and sesothelial cells should be recommented.
Discussion
Discussion is too long and descriptive.
At the end of the Discussion, the authors should provide the specific conclusions
of the work, like they have done in the abstract, referring to the data obtained.
Now these specific conclusions are lacking at the end of the paper.
Figures
Figure 2B is unclear. Some kinds of denotation, such as arrows should be
necessary.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests' below.