Adverse Outcome Pathway 298: Increase in Reactive Oxygen Species Leading to Human Treatment-Resistant Gastric Cancer

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This AOP Report addresses a highly important area of cancer biology, seeking to connect the environmental stress of chronic reactive oxygen species (ROS) accumulation with the critical clinical outcome of treatment resistance in gastric cancer. The manuscript is well-written and the overall argument for a mechanistic link is compelling and supported by existing literature (as evidenced by the reference list). The work is suitable for publication in Cancers pending the clarification and strengthening of the specific pathway details outlined in the major comments below.

Major comments:

1. As an AOP (Adverse Outcome Pathway) report, the pathway must be defined with clear, distinct steps. The current description is broad ("The pathway flow starting..."). The authors should explicitly define the Key Events (KEs) and the Key Event Relationships (KERs) that constitute this pathway. For the MIE, is this "increase in ROS" or a specific molecular target (e.g., oxidation of a specific protein/lipid)?  What are the key cellular changes (e.g., specific transcription factor activation, EMT, cancer stem cell induction) that bridge chronic ROS to resistance? Clearly define the "treatment resistance." Is it resistance to 5-FU, platinum-based therapy, radiation (as suggested by Ref 41), or a general multi-drug resistance phenotype?
2. The concept of "chronic ROS" is central to the hypothesis, distinguishing it from acute oxidative stress. This distinction needs a robust definition and justification. How is the level of ROS characterized as 'chronic' vs. 'acute'? Please discuss the specific cellular adaptations (e.g., upregulation of antioxidant systems like Nrf2 or changes in mitochondrial function) that maintain this chronic state.

3. The manuscript should expand on how chronic ROS in the cancer cells transforms the surrounding TME (e.g., induction of immunosuppression, promotion of angiogenesis, activation of fibroblasts). Clarifying this intercellular signaling mechanism would significantly strengthen the pathway model.

4. Are there specific ROS-sensitive targets or signaling nodes unique to gastric cancer that are not seen in, say, colorectal or pancreatic cancer? If so, highlight these unique features to justify the focus. If not, the authors should temper the title/abstract to reflect a pathway applicable to gastrointestinal cancers or solid tumors in general, before detailing its application to gastric cancer.  

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript presents a well-structured and conceptually valuable Adverse Outcome Pathway (AOP) titled “Increase in Reactive Oxygen Species (ROS) and Chronic ROS Leading to Human Treatment-Resistant Gastric Cancer (GC)”. The AOP delineates a mechanistic sequence from molecular initiating events (MIEs)—namely acute and sustained increases in ROS—through a series of biologically plausible key events (KEs), culminating in the adverse outcome of therapy-resistant gastric cancer. But I have several following concerns:

 

1. In the Introduction section, the statement "The NRF2-mediated oxidative stress response network included molecules related to the Regulation of EMT by growth factors pathway and Production of nitric oxide and reactive oxygen species in macrophages, such as PI3K and AKT" should be supported by relevant literature describing the processes involved in the NRF2-mediated oxidative stress response.
2. Should the Introduction section provide references discussing the regulatory relationship between NRF2 and EMT in gastric cancer?
3. In Table 2, the "Biological Plausibility" is rated as "moderate". Are there quantitative or systematic evaluation criteria for this rating?
4. In Section 2.2.4, specifically the "beta-catenin activation" part, does the discussion consider the role of its non-canonical pathways in EMT?
5. The text emphasizes the role of the Wnt/β-catenin pathway in EMT. Have other pathways with synergistic or antagonistic effects in gastric cancer been considered?
6. In Section 2.2.2, "Chronic ROS", its specific role or effects in gastric cancer models are not described.
7. For the statement in Section 2.2.5, "EMT plays an important role in therapeutic resistance and drug responses in human gastric cancer," can references providing in vivo evidence (e.g., from mouse models) supporting this conclusion in the context of gastric cancer be added?
8. Regarding the conclusion that this can be used for the "risk assessment of anti-cancer drugs," are there any specific application cases or examples?
9. The table in the text should be presented in a standard three-line format and should be avoided from spanning pages as much as possible.
10. Please unify the format of references in the article, including the author's name, the case of words in the title of the article, the writing of the name of the journal, and the page number.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript describes the adverse outcome pathway connecting chronic ROS accumulation, Wnt/β-catenin signaling, EMT and the development of therapy resistance in gastric cancer. Overall, the topic is quite relevant and the manuscript is clearly structured, fitting within the AOP communication format. I think the paper is suitable for publication after minor revisions.

Comments:

1. The discussion could be slightly more balanced. At the moment it focuses mainly on EMT, while other aspects of ROS-mediated tumor adaptation, like immune evasion or inflammatory feedback) could be briefly mentioned to give a more complete picture.
2.  It might be good to cite some newer studies discussing the link between oxidative stress and immune modulation in gastric cancer. For example, the review https://doi.org/10.3390/ijms26031156 could be introduced.

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Well addressed.

Reviewer 2 Report

Comments and Suggestions for Authors

The author have addressed all my concerns, I recommend accepting it in current form.