Established Liver Cell Lines: Are You Sure to Have the Right Ones?
Round 1
Reviewer 1 Report
This is a very informative and well-written commentary on important considerations that liver researchers should have in mind when designing experiments with liver cell lines. I would definitely recommend it not only to young researchers, but also to experienced ones, as an important knowledge resource. I only have some small suggestions for Dr. Weiskirchen to improve his already very good commentary.
- 'Introduction' should be deleted because there are no other sections in this commentary.
- Line 24: ‘ differentiation or … cells’. The sentence does not make sense and should be revised.
- Line 25: ‘permit’ should be replaced with ‘limit’ or ‘does not permit’.
- Lines 50-51: It should be written ‘continuously proliferating’ or ‘continuously growing’.
- Line 78: ‘proof’ should be replaced with ‘prove the’.
- Line 80: It would be good to make a clear statement at the end of this paragraph or after mentioning the examples of Chang liver cells and L-02 cells that all these misidentified cell lines should not be used under any circumstances for research purposes.
- Table 3: I am not sure if the aim of Dr. Weiskirchen was to discuss all 5 steps of the TOVEC concept. While he provides a detailed description in the text for the verificational step, not much is mentioned for the other steps. I think that table 3 provides enough details for step 2 and 4, but I find that some of the questions he poses in theoretical step 1 are not very straightforward to be answered in the beginning of a study. For instance: 'Which cell line is the most suitable for my experiments?' Let’s say one is interested to study the role of a pathway in liver tumor growth. Which of the multiple hepatoma cell lines should he/she choose? Also, how should one proceed if there is no previous literature using cell lines in similar experiments? In case such considerations fall in the scope of this commentary, it would be great if Dr. Weiskirchen add some more recommendations/answers to the questions he posed. I believe this would be very helpful in particular for young liver researchers.
- Table 3_Row 5: ‘Conformational’ should read ‘Confirmational’.
- Lines 152-156: I think it would also be useful to add 1-2 sentences at the end for the cases where the findings in cell lines do not match the primary cells or the in vivo data. Should one trash the cell line data? Does it mean that the cell line system is not reflecting the in vivo situation but it does not necessarily mean that the results are meaningless? Do we need to perform our experiments in multiple cell lines to judge if the obtained data are a peculiarity of a particular cell line?
- Suppl. Table S1 and S2: Is there a particular reason that the featured cell lines are mentioned? Are these the most commonly used? If yes, this should be mentioned in the title of the Tables. Although most of liver cells lines that I have access to are included in the tables, I would maybe add PH5CH8, HCC-M and HCC-T (Table S1) and JS1 (Table S2).
Author Response
Dear reviewer,
many thanks for your time in reading my comment. Please find in the attached pdf-file response to your suggestions.
Regards
Ralf Weiskirchen
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Established liver cell lines are widely used in liver research field and using correct cell lines are important for the reproducibility of research and the reliability of the results. Thus, this commentary is significant for liver research. The paper was well written and provided sufficient information for all researchers.
Author Response
Dear reviewer,
many thanks for your time in reading my comment.
Regards
Ralf Weiskirchen
Author Response File: Author Response.pdf
Reviewer 3 Report
Cell-line misidentification and contamination continue to be a scourge that professional researchers/cell biologists must avoid. This problem affects the quality of research and potentially leads to erroneous conclusions/publications. Therefore, it is important to highlight and insist on this matter to the scientific community. In this commentary Prof. Weiskirchen focuses on liver cells lines. He provides several tables with the information of misidentified and contaminated liver cell lines, information of most commonly used liver cell lines, and guidelines to follow when acquiring a new cell line for experiments.
My comments and suggestions below:
Major:
Double-check carefully the references; do not match the reported information (e.g., Table 1 Ref 16, Table S1 Ref 11…). In addition, several references are repeated (8/68, 17/100, 20/45, 23/58, 25/48, 26/49)
Consider including Fao-derived Can cells in Table S1 (see report by Peng et al. Cell Tissue Res. 2006 Fig. 1. PMID: 16231191). Include a supplementary Table with information of bile duct/cholangiocyte cell lines (e.g., NRC; PMID: 8569194, MMNK-1; PMID: 14966424…)
Lines 24-25; … Review the following sentences:
… prolonged culturing might lead to “differentiation” or growth promote of contaminating cells. => prolonged culturing might lead to dedifferentiation and/or cell culture contamination. It is considered that ordinary culture conditions lead to dedifferentiation of primary hepatocytes (see PMID: 26272144).
...their fragility and slow growth rate “permit” the efficient transfer of foreign nucleic acids... in vitro gene delivery to differentiated primary cells is significantly more difficult to achieve than in cell lines
Minor:
Line 44; …the Simian virus 40 large T antigen (SV40) => the simian virus-40 large tumor antigen (SV40T)
Line 48; …liver cells were immortalized by transfection with oncogenes (e.g., HPV E6E7, c-myc)… Include the reference/s
Line 52; …hepatic diseases. Redundant, mentioned in line 42
Ref 8; Hela => HeLa
Author Response
Dear reviewer,
many thanks for your time in reading my comment. Please find in the attached pdf-file response to your suggestions.
Regards
Ralf Weiskirchen
Author Response File: Author Response.pdf
