Exosomal Non-Coding RNAs: New Insights into the Biology of Hepatocellular Carcinoma

Round 1

Reviewer 1 Report

The manuscript “Exosomal non-coding RNAs: new insights into the biology of hepatocellular carcinoma” is a review manuscript on the role of exosomal non-coding RNAs as biomarkers for early diagnosis and prognosis of hepatocellular carcinoma. The authors provide a very good state-of-the-art and critical review on this topic, highlighting the most important information in the field and raising the most important concerns. However, there are some points that should be addressed to increase the quality of this work.

Major concerns:

1-      The definition of exosomes is sometimes elusive and the has been extensively and indiscriminately used in original and review articles although the isolation of vesicles in nm range is challenging. In general, the techniques used isolate a population of extracellular vesicles that include exosomes and other type of vesicles. Therefore, I strongly encourage the authors to discuss this point.

2-      The use of exosomal miRNA as diagnostic biomarkers is impeded by the method used to be extracted: plasma, serum, isolated cells. This issue should be discussed in the paper.

3-      Moreover, the authors should critically discuss the benefit of measuring exosome miRNas as a diagnostic tool, when compared with serum-free miRNAs.

4-      Critical discussion about the role of exosomal miRNAs, lncRNA and circRNAs as biomarkers and therapeutic targets used together or separately: which one is more promising, which one is more reliable, would add value to this beautiful review. I would also suggest a figure to summarize their role in HCC diagnosis.

5-      Some discussion on the most promising biomarkers and therapeutic targets should be included in conclusions. Please discuss what should be the next steps to translate some of the findings into clinics.

 Minor concerns:

1-      The metabolic liver diseases (NAFLD) is now considered a t major cause of HCC worldwide. Please include it in the introduction part

2-      Please increase the resolution of Figure 2 and try to design a white background.

There are some previous reviews on the same topic. Please mention them and discuss in the introduction what is the novelty of your story.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

In this review article, Zhang et al. have overviewed recent understanding of the noncoding RNA (ncRNA) cargoes of exosomes related to hepatocellular carcinoma (HCC) in terms of their development, diagnostics, and therapeutics for HCC. This manuscript is well written and conveys authors’ messages well. The figures and tables look organized. I have additional comments below.

Regarding Figure 1, the authors need to add what exosome-source cell was shown here.

Tables 1 and 2 indicate exosomal miRNAs as biomarkers for HCC and roles played by exosomal miRNAs in HCC, respectively. The authors need to include additional information such as the exosomal sources (cell, carcinoma tissue, or liquid biopsy).

Tables 3, 4, and 5 show lists of exosomal lncRNAs as HCC biomarkers, roles of exosomal lncRNAs in HCC, and roles of exosomal circRNAs in HCC, respectively. Related to the indication to Tables 1 and 2, the authors may wish to define the source cell/carcinoma tissue/liquid biopsy if available. In addition, if the effects of lncRNAs or circRNAs on regulating HCC via sponging specific miRNAs have been found in the previous references listed, the authors may wish to include them if necessary.

Figure 2 summarizes roles of ncRNAs in HCC and its concept sounds fine. I wonder if this Figure 2 has been cited in the text. Moreover, it looks to be better to include more explanations into the legends as well, although Figure 2 summarizes contents in the text. 

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

In this manuscript, Zhangang et al. provided a comprehensive review on the function of exosomal non-coding RNAs in hepatocellular carcinoma. As small extracellular vesicles released by the cells, exosomal vesicles contain diverse RNA molecules that play important roles in cancer progression. This review focuses on several types of non-coding RNAs, including miRNA, lncRNA, and circRNAs, covering major findings in the field. I have a few suggestions here:

 

1, Since a major focus of this review is miRNAs, I suggest a separate paragraph to provide an overview of how miRNAs function in general. Do those miRNAs have a conserved function to target cancer-associated genes’ 3’-UTR?

 

2, Although this manuscript provides many details on three types of non-coding RNAs, it does not include a few more types of non-coding RNAs that have been shown to affect cancer cells, such as piRNAs and tRNA fragments. I found a few papers here, and I hope, at least, the authors can mention them, which will make this review more inclusive:

 

Zhu, Lei, et al. "Exosomal tRNA-derived small RNA as a promising biomarker for cancer diagnosis." Molecular cancer 18.1 (2019): 1-5.

Cai, Aiting, et al. "PIWI-Interacting RNAs (piRNAs): Promising Applications as Emerging Biomarkers for Digestive System Cancer." Frontiers in Molecular Biosciences 9 (2022).

Riquelme, Ismael, et al. "The emerging role of piwi-interacting rnas (Pirnas) in gastrointestinal cancers: An updated perspective." Cancers 14.1 (2021): 202.

 

3, It would be better if the authors could include future directions or important questions for the researchers to focus on.

 

Overall, this is a well-written review with extensive knowledge and progress in the field. I suggest a minor revision before accepting it.

Author Response

Please see the attachment

Author Response File: Author Response.docx