Chimeric Antigen Receptor T Cell Therapy for Hepatocellular Carcinoma: Where Do We Stand?
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsA great review on the CAR T therapies being studied for HCC. My only comments would be to go over the introduction and CAR background sections and iron out some grammatical issues and smooth some rough sections that do not have a nice flow (staccato information points back to back instead of a narrative).
I've highlighted some other minor fixes and inclusions (attached file). Additionally, please redesign some of the figure labels as they are unclear/blurred (just the labels, the diagrams are fine).
Comments for author File: 
Comments.pdf
Only very minor sentence structure fixes to improve readability.
Author Response
Reviewer 1
A great review on the CAR T therapies being studied for HCC.
Comment 1: My only comments would be to go over the introduction and CAR background sections and iron out some grammatical issues and smooth some rough sections that do not have a nice flow (staccato information points back-to-back instead of a narrative).
Response to comment 1: We have revised all the sections needed, as per suggestion.
Comment 2: I've highlighted some other minor fixes and inclusions (attached file).
Line 22: immunological mechanisms of HCC
Response to comment 2: We have revised as suggested (lines 22-23).
Comment 3: I've highlighted some other minor fixes and inclusions (attached file).
Intro: Should look over again and smooth out. Many sentences are somewhat rough and do not flow. Ie HCC remains a global health care challenge, as its incidence is estimated at more than 1 million cases by 2025. Should read HCC remains a global health care challenge with a million potential cases (insert country/region) predicted to occur by 2025.
Response to comment 3: We have revised as suggested (lines 34-37).
Comment 4: I've highlighted some other minor fixes and inclusions (attached file).
Line 108: allows circumvention of MHC restriction.
Response to comment 4: We have revised as suggested (lines 75-77).
Comment 5: I've highlighted some other minor fixes and inclusions (attached file).
Go over and smooth out. The descriptions of 1-5th generation CARs and CAR mechanics does not flow well.
Response to comment 5: We have revised this section to flow better as suggested (lines 142-175).
Comment 6: I've highlighted some other minor fixes and inclusions (attached file).
Could add the latest inducible CARs /CAR switching/ and the introduction of logic gated CARs (NOT and IF-BETTER gates), or to both antigens simultaneously (AND-gate).
Response to comment 6: We have added the information, as suggested (lines 176-233).
Comment 7: I've highlighted some other minor fixes and inclusions (attached file).
Line 277: This is a bi-specific CAR that targets GPC3 and PD1 (not really PD1:PDL1), make more clear
Response to comment 7: We have revised as suggested (line 399).
Comment 8: I've highlighted some other minor fixes and inclusions (attached file).
Line 359: Should explain how these logic gated CARs work in your general CAR synopsis (1-5th gen)
Response to comment 8: We have added information on this technology, as suggested (lines 176-233).
Comment 9: I've highlighted some other minor fixes and inclusions (attached file).
FIGURE 4 needs to be fixed, image blurry/labels blurry.
Response to comment 9: We have revised the figure 4, substituting the figure labels with bigger and bold font in order to be clearer, as suggested.
Comment 10: I've highlighted some other minor fixes and inclusions (attached file).
Line 512: Define photothermal therapy
Response to comment 10: We have added the definition of photothermal therapy, as suggested (lines 645-646).
Comment 11: Additionally, please redesign some of the figure labels as they are unclear/blurred (just the labels, the diagrams are fine).
Response to comment 11: We have revised all the figures, substituting the figure labels with bigger and bold font in order to be clearer, as suggested. Moreover, high resolution images will be submitted to the journal after acceptance.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors tried to show the development of car-T therapy in HCC immunotherapy now from a global perspective and looked forward to the ongoing research directions in light of the future challenges. But the manuscript suffers from the following issues:
#1 The logic of the article is rather confusing. The main structure of the lines does not match with the title, and the contents of 1-4 subheadings should be presented as the content of the introduction. the development history of car-T and immunotherapy are not the focus of the review. The related contents are too long and do not contribute any meaning to the main idea of the article. The review of the tumor immune microenvironment of HCC also did not serve the car-T therapy of HCC well, making the article was poorly structured.
#2 In recent years, the tertiary lymphoid structure TLS has become a research hotspot of tumor immune microenvironment, which is also significant in HCC. TLS plays a great role in the formation and development of TME and even in the late stage of clinical intervention. The car-T therapy will be affected by it as well. The authors should add to this section instead of spending a huge amount of space on what is already known in the academic community.
#3 The presentation related to car and car-T therapy lacks representation of HCC. The authors quote and summarize a lot of generalizations that deviate from the title and main idea of the article.
#4 The manuscript contains little novelty in presenting current problems and solutions, and then the language is rather general. Neither does it connect with the previous section, which describes the current status of car-t therapy for HCC by target classification, nor fulfills the goal of the manuscript, which is "to provide new ideas for car-t therapy".
#5 Not comprehensive enough, especially the section on challenging solutions for car-t. The manuscript only mentions some of the challenges in solid tumors, and common issues such as drug resistance are not addressed.
#6 The introduction for car could incorporate a bit more about the specific clinical treatment process and needs, to make the manuscript more in line with the theme of how to proceed with car-t treatment.
#7 What is the mechanism of t-cell depletion and what is its significance in the clinical practice of car-T therapy for HCC should be discussed.
Comments on the Quality of English LanguageMinor editing of English language required.
Author Response
The authors tried to show the development of car-T therapy in HCC immunotherapy now from a global perspective and looked forward to the ongoing research directions in light of the future challenges. But the manuscript suffers from the following issues.
Comment 1: The logic of the article is rather confusing. The main structure of the lines does not match with the title, and the contents of 1-4 subheadings should be presented as the content of the introduction. the development history of car-T and immunotherapy are not the focus of the review. The related contents are too long and do not contribute any meaning to the main idea of the article. The review of the tumor immune microenvironment of HCC also did not serve the car-T therapy of HCC well, making the article was poorly structured.
Response to comment 1: We would like to thank the reviewer for this comment. We have revised as suggested. We have drastically reduced the first 4 subheadings, and we have incorporated only the related data to the introduction section.
Comment 2: In recent years, the tertiary lymphoid structure TLS has become a research hotspot of tumor immune microenvironment, which is also significant in HCC. TLS plays a great role in the formation and development of TME and even in the late stage of clinical intervention. The car-T therapy will be affected by it as well. The authors should add to this section instead of spending a huge amount of space on what is already known in the academic community.
Response to comment 2: We appreciate this comment. In the revised manuscript, we have added a section describing the role of TLS in the tumor microenvironment and its potential contribution to the CAR-T cell therapy, as suggested (lines 272-308).
Comment 3: The presentation related to car and car-T therapy lacks representation of HCC. The authors quote and summarize a lot of generalizations that deviate from the title and main idea of the article.
Response to comment 3: The section 2 titled “CAR-T cell structure” is indeed not focused to HCC. It actually presents an overview of CAR structure, the main mechanisms by which this technology works and lastly the progression from the first to the fifth generation of CARs. An addition to this section is a brief description of the latest inducible CARs /CAR switching/ and the introduction of logic gated CARs, as requested by reviewer 1 (lines 176-233). Although, these data do not focus on hepatocellular carcinoma per se, we believe that provide a solid introduction for readers to grasp the underlying principles of how CAR-T cell technology operates in readers not so familiar with this technology. Regarding, sections “Immunotherapy for HCC management” and “Immunological mechanisms of HCC development”, we consort with your assessment that they contain redundant information in relation to the manuscript's aims, and we have subsequently removed them.
Comment 4: The manuscript contains little novelty in presenting current problems and solutions, and then the language is rather general. Neither does it connect with the previous section, which describes the current status of car-t therapy for HCC by target classification, nor fulfills the goal of the manuscript, which is "to provide new ideas for car-t therapy".
Response to comment 4: The aim of the current review was to describe the adoptive immunotherapy for HCC, with a special focus on CAR-T cells and the biological rationale behind this process. In the section, “CAR-T cell therapy targets for HCC”, we describe the latest evidence based on clinical trials and preclinical animal models utilizing CAR-T cells in the setting of HCC. Moreover, we have compiled and visualized all data into a single figure (figure 3) for better understanding by the readers. The discussion of promising strategies to ameliorate CAR-mediated T cell efficacy constituted the secondary aim of this review. In the section “Strategies to improve the efficacy of CAR-T cell therapy for HCC” we have discussed the approaches and strategies which have been utilized or have been under investigation to overcome the emerged challenges. In the fourth figure, we have also depicted these strategies. As this section did not constitute the primary focus of our study, it was intentionally more concise and briefer. However, in the revised manuscript, we have added crucial information such as the prominent role of TLS and of T-cell depletion on CAR T cell therapy per your suggestion, and the latest research on the novel CAR T cells design and optimization, as reviewer 1 suggested, and we hope that these changes will improve our manuscript and meet your requirements.
Comment 5: Not comprehensive enough, especially the section on challenging solutions for car-t. The manuscript only mentions some of the challenges in solid tumors, and common issues such as drug resistance are not addressed.
Response to comment 5: In the revised manuscript, we have added information on the drug resistance and how we can overcome this challenge, as suggested (lines 661-688).
Comment 6: The introduction for car could incorporate a bit more about the specific clinical treatment process and needs, to make the manuscript more in line with the theme of how to proceed with car-t treatment.
Response to comment 6: We have added a section describing the manufacturing process of CAR T-cells and discussing challenges and alternatives to enhance the therapeutic potency of CAR therapy (lines 235-271).
Comment 7: What is the mechanism of t-cell depletion and what is its significance in the clinical practice of car-T therapy for HCC should be discussed.
Response to comment 7: We have added a section describing the role of T-cell depletion in overcoming the challenges raised during CAR T-cell therapy (lines 309-345).
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsAuthors addressed most of issues put forward by referees. Small typos and mis-editing remains to be corrected. Such as full spelling of CRS presents twice in line 339 and 584. Line 604 "and eradicate tumor cells" the 1st "and" should be replaced by ",". Authors need to go over the MS to avoid such problems.
Comments on the Quality of English LanguageMinor editing of English language required.
Author Response
Reviewer 2
Authors addressed most of issues put forward by referees.
Comment 1: Small typos and mis-editing remains to be corrected. Such as full spelling of CRS presents twice in line 339 and 584.
Response to comment 1: We have revised as suggested.
Comment 2: Line 604 "and eradicate tumor cells" the 1st "and" should be replaced by ",".
Response to comment 2: We believe that the use of “by” instead of “and” will modify the meaning of the sentence.
Comment 3: Authors need to go over the MS to avoid such problems.
Response to comment 3: Following your suggestions, we have completed the English editing throughout the entire document.
