Review papers with raw data transparency

Summary of the manuscript

Authors performed a focused literature review (PubMed queries described) and used circAtlas to retrieve circRNA IDs, TargetScan to inspect miRNA 3'UTR targeting, and Cytoscape/ClueGO to build GO networks linking circRNAs and KLF4; they report specific circRNA/miRNA axes (e.g., ciRS-7/miR-7, circPRMT5/miR-7-5p, circLECRC/miR-135b-5p, circPLEKHM3/miR-9) and highlight that circRNAs can relieve miRNA-mediated inhibition of KLF4, shifting KLF4 to act as tumor promoter or suppressor depending on tissue and disease stage Primary review circRNA miRNA KLF4

What the paper does well

• Systematic capture of reported circRNA/miRNA axes acting on KLF4 across multiple tumor types and clear table/figures summarizing axes and contexts Table and network figures
• Appropriate emphasis on context dependence (tumor type and disease stage) for KLF4 function, matching prior literature that KLF4 is often epigenetically regulated and context dependent KLF4 epigenetic review

Main limitations and critical concerns

1. Over-reliance on ceRNA inference and predictive tools. The review often equates predicted MRE presence or correlation with functional repression/relief, but predictive binding (TargetScan/circAtlas) does not prove functional sponging or causal regulation in vivo; many axes cited lack orthogonal validation such as Ago2 IP, luciferase 3'UTR reporters, rescue experiments, or in vivo modulation Limits of validation in review
2. Heterogeneous quality of primary evidence. The axes drawn together come from diverse study types (cell lines, small patient cohorts, single animal models) with variable sample sizes and controls — pooling them into a single mechanistic narrative risks over-generalization; the manuscript acknowledges stage dependence but does not systematically grade evidence by study type or strength Heterogeneous evidence base
3. Missing raw data and reproducibility details. As a review, original experimental data are not deposited; the bioinformatic network reconstruction (CircAtlas queries, ClueGO settings) lacks fully reproducible parameters and downloadable files, which hinders reproducibility of the network analysis and re-use by others Data availability and methods gaps

Key biological points supported by the literature

• Multiple circRNAs have been reported to act as miRNA sponges that affect KLF4 expression in specific cancers (examples: ciRS-7/miR-7-5p in CRC/HCC; circPRMT5/miR-7-5p in Wilms tumor; circLECRC/miR-135b-5p in CRC; circPLEKHM3/miR-9 in ovarian cancer) — these are collected in the review and referenced to original studies where available circRNA miRNA KLF4 axes list
• KLF4 itself is a context dependent transcription factor with established epigenetic regulation (promoter methylation, histone marks, ncRNA control) and pleiotropic roles in stemness, EMT, immune interactions and chemoresistance across tumors; the review aligns with prior KLF4-focused reviews KLF4 epigenetic regulation review

Where the field should go next (concrete suggestions)

1. Standardize evidence tiers for ceRNA axes: require at minimum (a) circRNA differential expression in tumor versus control; (b) miRNA correlation and predicted MRE; (c) biochemical Ago2 coimmunoprecipitation showing circRNA–miRNA interaction; (d) 3'UTR reporter showing miRNA targeting of KLF4; (e) rescue experiments (circRNA overexpression or knockdown alters KLF4 protein and phenotype, reversible by miRNA mimic/inhibitor). When these five steps are present the axis is high-confidence.
2. Provide reproducible bioinformatics: publish circAtlas query exports, Cytoscape session files, ClueGO parameters, and code notebooks so readers can re-run network and GO analyses (the reviewed paper used these tools but did not supply the underlying files) Reproducibility gap
3. Systematic functional atlas: a coordinated multi-tumor experimental effort (cell lines, organoids, PDXs) perturbing top-ranked circRNAs (e.g., ciRS-7, circPRMT5) and measuring KLF4 RNA/protein, downstream transcriptome, stemness markers, EMT, and drug response would clarify tissue-specific roles.

Practical takeaways for researchers

• Treat circRNA->miRNA->mRNA axes as working hypotheses until they pass biochemical and rescue validation; do not assume sponging from sequence alone Caveat about predictions
• When designing therapeutic strategies, consider tumor type and stage because KLF4 can be tumor promoting or suppressive depending on context; modulating a circRNA that raises KLF4 in one cancer could be deleterious in another KLF4 context dependence

Confidence and evidence grading

The review is a useful synthesis and hypothesis generator (confidence moderate) but many specific claims about causal regulatory axes require stronger, orthogonal experimental validation (confidence low to moderate per axis). The global concept that circRNAs can relieve miRNA repression of KLF4 is biologically plausible and supported by specific validated cases (e.g., ciRS-7/miR-7 family interactions have strong experimental backing in multiple contexts) but mapping from interaction to phenotype (stemness, chemoresistance) is unevenly validated across tumor types Review evidence heterogeneity

Selected citations to anchor main claims

• Primary review: circRNA/miRNA networks and KLF4 (the paper under analysis) Primary circRNA/miRNA KLF4 review
• KLF4 epigenetic regulation and context dependence review (supports context claims) KLF4 epigenetics review

Actionable next steps and resources

1. Re-run circAtlas queries and export circIDs used in the paper; request authors to share the Cytoscape session/ClueGO outputs for reproducibility (authors used these tools but did not provide session files) CircAtlas Cytoscape usage
2. Prioritize experimental validation of highest-confidence axes (e.g., ciRS-7/miR-7/KLF4 in HCC/CRC; circLECRC/miR-135b-5p/KLF4 in CRC) with the five-step evidence ladder described above.