Different HSP90 Inhibitors Exert Divergent Effect on Myxoid Liposarcoma In Vitro and In Vivo

Round 1

Reviewer 1 Report

In this manuscript, Vannas and coworkers performed in vitro and vivo studies aimed at testing 3 different HSP90 inhibitors, namely 17-DMAG, AUY922 and STA-9090, as possible therapeutic options for patients with Myxoid Liposarcoma (MLS). To perform in vitro studies, authors used 402-91, 1765-923 and 2645-94 MLS cell lines. Results showed that inhibitors induce a G2/M arrest of the cells and increase levels of cleaved-caspase 3. In these experiments, AUY922 resulted the inhibitor more effective at lowest concentration. Then authors tested the effect of the 3 inhibitors on pRTK levels on the 2 MLS cell lines carrying the most common FUS-DDIT3 variants. Results showed that levels of 4 pRTK, EGFR, ERBB3, INSR, EPHB3 are commonly down-regulated in both cell lines. In addition, authors showed that HSP90 inhibitors induce a reduction of MAPK and PI3K/AKT signaling pathways, with AUY922 showing the lowest efficacy in the down-regulation of these pathways. In the last part of the manuscript, authors performed in vivo experiment with a PDX model of MLS. Results showed that treatment with 17-DMAG reduces tumor growth, while treatment with AUY922 inhibitor induce an increase in tumor growth that could be reverted by the switch to treatment with 17-DMG. In vitro combination drug assays revealed a drug synergy between HSP90 inhibitors and trabectidin.

Data here presented are of interest, but, in my opinion, the manuscript is too descriptive and several major issues should be addressed:

-Main results of the in vitro experiments should be summarized in a table, along with molecular characterization of the MLS cell lines, and discussed for their potential clinical applications. Why did the authors tested for pRTK levels only the 2 MLS cell lines with the most common FUS-DDIT3 variants, but validate results in all 3 MLS cell lines?

-Authors should explain and discuss why they reported how HSP90 inhibitors affect MLS morphology. Are those tumor morphology features related to tumor aggressiveness or patient clinical outcome?

 

Minor issues:

-Please add statistical analysis where replicates have been tested.

-Figure 3B is not cited in the text, please add it.

-Why did the authors tested 2 doses of trabectidin in combination drug assays?

-Please verify the number of the Supplementary Figures cited in the last paragraph ‘Combination treatment of HSP90 inhibitors with Doxorubicin or Trabectidin’.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

line 314: route of administration is not reported

from line 348 through 354 before the full-stop: move to introduction

line 349-50 substitute "potency" with "activity"

une 359: omit "interestingly" since the synergy is known 

line 401 substitute "efficacy" with "activity"

line 427: substitute "instigated" with "initiated"

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have adequately addressed all my concerns and queries. I have only a minor comment: Authors should better specify the differences between the FUS-DDIT3 variants (type 1, type 2 and type 6 fusions) of the MLS cell lines of the study.