Reviewer's report
Title:Sphere-forming cell subpopulations with cancer stem cell properties in
human hepatoma cell lines
Version: 1Date:25 January 2011
Reviewer: Nicholas barker
Reviewer's report:
Cao et al:
This study evaluates the existence of cancer stem cells in human liver cancer
cell-lines using sphere-forming and in-vivo transplantation assays.
Cancer stem cells are undoubtedly a hot topic and formal demonstration of their
existence in liver cancer would have major therapeutic implications. However, the
findings of this study are preliminary, lack mechanistic insight and do not
represent a significant advance on those already published.
Comments:
1) The authors report that different cell-lines harbor sub-populations with
sphere-forming capabilities in-vitro. However, there is no attempt to compare the
efficacies of non-tumorigenic versus highly tumorigenic (eg, HepG2 vs
MHCC97H) cell-lines, or Hep+ versus Hep- in this assay. Such information is
crucial for drawing generally applicable conclusions.
2) Related to the above point, it is also important to directly compare the
sphere-forming and in-vivo tumorigenic efficacies of at least one other cell-line in
addition to PLC/PRF/5 and relate this to CSC activity/frequency.
3) The observations on resistance to chemotherapeutic agents should be
extended to include other common drugs with different mechanisms of action, eg,
doxyrubicin (ABC transporter blocker). Is there preferential survival of candidate
CSC markers in this assay (easily tested by IHC for CD133, CD13, CD44 etc)?
4) The correlation between increased tumorigenicity and enhanced expression of
candidate cancer stem cell markers in figure 4 is highly tentative. As a minimum,
the Western blots need to be accurately quantified. However, it would be far
more informative to demonstrate by IHC analysis that populations of cells
co-expressing markers such as CD133 and CD44 etc are enriched in the
spheres. CD13 should also be included here (See Haraguchi et al., JCI 2010
120:3326).
5) The link with aberrant activation of Notch signaling, although preliminary are
potentially interesting given the current interest in defining signaling pathways
linked to maintenance of CSC function in-vivo. This could easily by functionally
evaluated by blocking the Notch pathway in the sphere colonies with
commercially-available gamma-secretase inhibitors.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Reviewer's report
Title:Sphere-forming cell subpopulations with cancer stem cell properties in
human hepatoma cell lines
Version: 1Date:25 January 2011
Reviewer: Nicholas barker
Reviewer's report:
Cao et al:
This study evaluates the existence of cancer stem cells in human liver cancer
cell-lines using sphere-forming and in-vivo transplantation assays.
Cancer stem cells are undoubtedly a hot topic and formal demonstration of their
existence in liver cancer would have major therapeutic implications. However, the
findings of this study are preliminary, lack mechanistic insight and do not
represent a significant advance on those already published.
Comments:
1) The authors report that different cell-lines harbor sub-populations with
sphere-forming capabilities in-vitro. However, there is no attempt to compare the
efficacies of non-tumorigenic versus highly tumorigenic (eg, HepG2 vs
MHCC97H) cell-lines, or Hep+ versus Hep- in this assay. Such information is
crucial for drawing generally applicable conclusions.
2) Related to the above point, it is also important to directly compare the
sphere-forming and in-vivo tumorigenic efficacies of at least one other cell-line in
addition to PLC/PRF/5 and relate this to CSC activity/frequency.
3) The observations on resistance to chemotherapeutic agents should be
extended to include other common drugs with different mechanisms of action, eg,
doxyrubicin (ABC transporter blocker). Is there preferential survival of candidate
CSC markers in this assay (easily tested by IHC for CD133, CD13, CD44 etc)?
4) The correlation between increased tumorigenicity and enhanced expression of
candidate cancer stem cell markers in figure 4 is highly tentative. As a minimum,
the Western blots need to be accurately quantified. However, it would be far
more informative to demonstrate by IHC analysis that populations of cells
co-expressing markers such as CD133 and CD44 etc are enriched in the
spheres. CD13 should also be included here (See Haraguchi et al., JCI 2010
120:3326).
5) The link with aberrant activation of Notch signaling, although preliminary are
potentially interesting given the current interest in defining signaling pathways
linked to maintenance of CSC function in-vivo. This could easily by functionally
evaluated by blocking the Notch pathway in the sphere colonies with
commercially-available gamma-secretase inhibitors.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Please review this paper.
user
Reviewer's report
Title:Sphere-forming cell subpopulations with cancer stem cell properties in
human hepatoma cell lines
Version: 1Date:25 January 2011
Reviewer: Nicholas barker
Reviewer's report:
Cao et al:
This study evaluates the existence of cancer stem cells in human liver cancer
cell-lines using sphere-forming and in-vivo transplantation assays.
Cancer stem cells are undoubtedly a hot topic and formal demonstration of their
existence in liver cancer would have major therapeutic implications. However, the
findings of this study are preliminary, lack mechanistic insight and do not
represent a significant advance on those already published.
Comments:
1) The authors report that different cell-lines harbor sub-populations with
sphere-forming capabilities in-vitro. However, there is no attempt to compare the
efficacies of non-tumorigenic versus highly tumorigenic (eg, HepG2 vs
MHCC97H) cell-lines, or Hep+ versus Hep- in this assay. Such information is
crucial for drawing generally applicable conclusions.
2) Related to the above point, it is also important to directly compare the
sphere-forming and in-vivo tumorigenic efficacies of at least one other cell-line in
addition to PLC/PRF/5 and relate this to CSC activity/frequency.
3) The observations on resistance to chemotherapeutic agents should be
extended to include other common drugs with different mechanisms of action, eg,
doxyrubicin (ABC transporter blocker). Is there preferential survival of candidate
CSC markers in this assay (easily tested by IHC for CD133, CD13, CD44 etc)?
4) The correlation between increased tumorigenicity and enhanced expression of
candidate cancer stem cell markers in figure 4 is highly tentative. As a minimum,
the Western blots need to be accurately quantified. However, it would be far
more informative to demonstrate by IHC analysis that populations of cells
co-expressing markers such as CD133 and CD44 etc are enriched in the
spheres. CD13 should also be included here (See Haraguchi et al., JCI 2010
120:3326).
5) The link with aberrant activation of Notch signaling, although preliminary are
potentially interesting given the current interest in defining signaling pathways
linked to maintenance of CSC function in-vivo. This could easily by functionally
evaluated by blocking the Notch pathway in the sphere colonies with
commercially-available gamma-secretase inhibitors.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
assistant