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Relationship: 2204

Title

A descriptive phrase which clearly defines the two KEs being considered and the sequential relationship between them (i.e., which is upstream, and which is downstream). More help

Decrease, ATP pool leads to Decrease, Cell proliferation

Upstream event

The causing Key Event (KE) in a Key Event Relationship (KER). More help

Decrease, ATP pool

Downstream event

The responding Key Event (KE) in a Key Event Relationship (KER). More help

Decrease, Cell proliferation

Key Event Relationship Overview

The utility of AOPs for regulatory application is defined, to a large extent, by the confidence and precision with which they facilitate extrapolation of data measured at low levels of biological organisation to predicted outcomes at higher levels of organisation and the extent to which they can link biological effect measurements to their specific causes.Within the AOP framework, the predictive relationships that facilitate extrapolation are represented by the KERs. Consequently, the overall WoE for an AOP is a reflection in part, of the level of confidence in the underlying series of KERs it encompasses. Therefore, describing the KERs in an AOP involves assembling and organising the types of information and evidence that defines the scientific basis for inferring the probable change in, or state of, a downstream KE from the known or measured state of an upstream KE. More help

AOPs Referencing Relationship

AOP Name	Adjacency	Weight of Evidence	Quantitative Understanding	Point of Contact	Author Status	OECD Status
Uncoupling of oxidative phosphorylation leading to growth inhibition via decreased cell proliferation	adjacent	Moderate	Moderate	You Song (send email)	Open for citation & comment	WPHA/WNT Endorsed
Mitochondrial ATP synthase antagonism leading to growth inhibition (1)	adjacent			You Song (send email)	Under development: Not open for comment. Do not cite
Mitochondrial complex III antagonism leading to growth inhibition (1)	adjacent			You Song (send email)	Under development: Not open for comment. Do not cite
Excessive reactive oxygen species leading to growth inhibition via fatty acid oxidation and reduced cell proliferation	adjacent			You Song (send email)	Under development: Not open for comment. Do not cite
Increase in reactive oxygen species leading to growth inhibition via lipid peroxidation and decreased cell proliferation	adjacent	High	Moderate	You Song (send email)	Under development: Not open for comment. Do not cite	Under Development
Increase in reactive oxygen species leading to growth inhibition via protein oxidation and decreased cell proliferation	adjacent	High	Moderate	You Song (send email)	Under development: Not open for comment. Do not cite	Under Development

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KER.In general, this will be dictated by the more restrictive of the two KEs being linked together by the KER. More help

Term	Scientific Term	Evidence	Link
zebrafish	Danio rerio	High	NCBI
human	Homo sapiens	High	NCBI

Sex Applicability

An indication of the the relevant sex for this KER. More help

Sex	Evidence
Unspecific	High

Life Stage Applicability

An indication of the the relevant life stage(s) for this KER. More help

Term	Evidence
Embryo	High

Key Event Relationship Description

Provides a concise overview of the information given below as well as addressing details that aren’t inherent in the description of the KEs themselves. More help

This key event relationship describes reduced adenosine triphosphate (ATP) supply leading to reduced cell proliferation (cell growth, division or a combination of these).

Evidence Collection Strategy

Include a description of the approach for identification and assembly of the evidence base for the KER. For evidence identification, include, for example, a description of the sources and dates of information consulted including expert knowledge, databases searched and associated search terms/strings. Include also a description of study screening criteria and methodology, study quality assessment considerations, the data extraction strategy and links to any repositories/databases of relevant references.Tabular summaries and links to relevant supporting documentation are encouraged, wherever possible. More help

Update - non-endorsed (by You Song, 06/10/2026)

The evidence for this KER was collected through a manual review of the published literature, without the use of AI-based tools. Canonical knowledge on the ATP dependence of cell proliferation was taken from the review literature (Kingston and Narlikar, 1999; Bonora et al., 2012). Studies that measured both ATP and cell proliferation in the same experiment after exposure to chemicals that deplete ATP were identified for empirical support (Koczor et al., 2009; Kuruvilla et al., 2003; Sithara et al., 2017). Studies on the quantitative relationship between cellular ATP content and proliferation were reviewed for quantitative understanding (Ahmann et al., 1987; Crouch et al., 1993; Nieminen et al., 1994). No formal study quality assessment was performed.

Evidence Supporting this KER

Addresses the scientific evidence supporting KERs in an AOP setting the stage for overall assessment of the AOP. More help

The overall evidence supporting Relationship 2204 is considered moderate.

Biological Plausibility

Addresses the biological rationale for a connection between KEupstream and KEdownstream. This field can also incorporate additional mechanistic details that help inform the relationship between KEs, this is useful when it is not practical/pragmatic to represent these details as separate KEs due to the difficulty or relative infrequency with which it is likely to be measured. More help

The biological plausibility of Relationship 2204 is considered high.

Rationale: Cell proliferation is a well-known ATP-dependent process. Cell division processes, such as the mitotic cell cycle uses ATP for chromosome movements and DNA replication (Kingston 1999). The synthetic processes of major cellular components that are necessary for cell structure and growth, such as proteins and lipids, also require sufficient ATP supply (Bonora 2012). Depletion of ATP therefore has a negative impact on these processes.

Empirical Evidence

Provides specific (citable) evidence that supports the idea of a change in the upstream KE (KEupstream) leading to, or being associated with, a subsequent change in the downstream KE (KEdownstream), assuming the perturbation of KEupstream is sufficient. More help

The empirical support of Relationship 2204 is considered moderate.

Evidence:

Incidence concordance: Exposure of human HeLa cells to 50 µM of the uncoupler CCCP for 1h led to 25% reduction in ATP, whereas a non-significant reduction in cell proliferation (Koczor 2009).
Incidence concordance: Exposure of human RD cells to 20 µM of the uncoupler CCCP for 2h led to 20% ATP depletion, whereas a non-significant decrease in cell proliferation (Kuruvilla 2003).
Incidence concordance: Exposure of human SE480 cells to 150 µM of the uncoupler flavanoid morin for 48h led to 35% ATP depletion and 35% reduction in cell proliferation (Sithara 2017).

Uncertainties and Inconsistencies

Addresses inconsistencies or uncertainties in the relationship including the identification of experimental details that may explain apparent deviations from the expected patterns of concordance. More help

There are currently no inconsistencies based on the supporting literature.

Known modulating factors

This table captures specific information on the MF, its properties, how it affects the KER and respective references.1.) What is the modulating factor? Name the factor for which solid evidence exists that it influences this KER. Examples: age, sex, genotype, diet 2.) Details of this modulating factor. Specify which features of this MF are relevant for this KER. Examples: a specific age range or a specific biological age (defined by...); a specific gene mutation or variant, a specific nutrient (deficit or surplus); a sex-specific homone; a certain threshold value (e.g. serum levels of a chemical above...) 3.) Description of how this modulating factor affects this KER. Describe the provable modification of the KER (also quantitatively, if known). Examples: increase or decrease of the magnitude of effect (by a factor of...); change of the time-course of the effect (onset delay by...); alteration of the probability of the effect; increase or decrease of the sensitivity of the downstream effect (by a factor of...) 4.) Provision of supporting scientific evidence for an effect of this MF on this KER. Give a list of references. More help

Update - non-endorsed (by You Song, 06/10/2026)

No modulating factors with quantified effects on this KER have been identified. The factors below are indicated by the literature cited in this KER.

Modulating factor	Details	Effects on the KER	References
Cell type and species	Cell types and species in which ATP and proliferation are measured	The quantitative relationship between cellular ATP and cell proliferation varies across biological systems.	Ahmann et al., 1987; Crouch et al., 1993
Severity of ATP depletion	Degree of ATP depletion relative to the normal ATP level	In mammalian cells, ATP depletion beyond a threshold of about 85–90% of normal is associated with cell death rather than proliferation arrest.	Nieminen et al., 1994

Quantitative Understanding of the Linkage

Captures information that helps to define how much change in the upstream KE, and/or for how long, is needed to elicit a detectable and defined change in the downstream KE. More help

The quantitative understanding of Relationship 2204 is moderate.

Rationale: Quantitative relationships between total ATP and cell proliferation have been extensively investigated (Ahmann 1987; Crouch 1993). In general, a monotonic positive relationship can be assumed for the two events, albeit the actual quantitative relationship can vary across biological systems (e.g. cell types and species). It has also been suggested that a threshold of ATP depletion (85-90% compared to normal status) may exist to determine whether proliferation arrest (<85-90%) or cell death (>85-90%) will be triggered in mammals (Nieminen 1994).

Response-response Relationship

Provides sources of data that define the response-response relationships between the KEs. More help

Update - non-endorsed (by You Song, 06/10/2026)

A monotonic positive relationship between total cellular ATP and cell proliferation can be assumed (Ahmann et al., 1987; Crouch et al., 1993). The available studies that measured both events in the same experiment suggest that small decreases in ATP are not sufficient to reduce proliferation. In human HeLa and RD cells, ATP reductions of 25% (50 µM CCCP, 1 h) and 20% (20 µM CCCP, 2 h) were accompanied by non-significant decreases in proliferation (Koczor et al., 2009; Kuruvilla et al., 2003). In human SW480 cells, a 35% ATP depletion after 48 h of exposure to 150 µM morin was accompanied by a 35% reduction in proliferation (Sithara et al., 2017). These data points come from different stressors, cell types, and exposure durations, so they cannot be combined into a single response-response function, and the general form of the relationship (linear, threshold, or sigmoidal) has not been defined. In mammalian cells, a threshold of ATP depletion of about 85–90% relative to normal has been suggested to separate proliferation arrest (depletion below the threshold) from cell death (depletion above it) (Nieminen et al., 1994). The precision with which a measured decrease in ATP predicts a decrease in proliferation has not been quantified.

Time-scale

Information regarding the approximate time-scale of the changes in KEdownstream relative to changes in KEupstream (i.e., do effects on KEdownstream lag those on KEupstream by seconds, minutes, hours, or days?). More help

Update - non-endorsed (by You Song, 06/10/2026)

The time-scale of this KER has not been quantified. In the available studies, ATP was reduced by 20–25% after 1–2 h of exposure to CCCP without a significant decrease in proliferation, whereas a 35% reduction in ATP after 48 h of exposure to morin was accompanied by a 35% reduction in proliferation (Koczor et al., 2009; Kuruvilla et al., 2003; Sithara et al., 2017). This is consistent with a lag between ATP depletion and measurable effects on proliferation, but because the studies used different stressors and cell types, the length of the lag cannot be estimated.

Known Feedforward/Feedback loops influencing this KER

Define whether there are known positive or negative feedback mechanisms involved and what is understood about their time-course and homeostatic limits. More help

Update - non-endorsed (by You Song, 06/10/2026)

No feedforward or feedback loops have been characterized for this KER in the studies cited here. Cells can maintain ATP by increasing ATP production or by reducing ATP consumption, which would influence how much ATP depletion is needed to reduce proliferation, but the extent, time course, and homeostatic limits of these compensatory responses have not been quantified for this KER. They are therefore described here and not represented as separate KEs.

Domain of Applicability

A free-text section of the KER description that the developers can use to explain their rationale for the taxonomic, life stage, or sex applicability structured terms. More help

Taxonomic applicability

Relationship 2204 is considered applicable to all eukaryotes, as ATP and cell proliferation are known to be tightly coupled in animals, plants and some microorganisms.

Sex applicability

Relationship 2204 is considered applicable to all sexes, as ATP-dependent cell proliferation are used by both males and females in eukaryotes.

Life-stage applicability

Relationship 2204 is considered applicable to all life stages, as ATP-dependent cell proliferation is an essential process for an organism throughout the entire life.

References

List of the literature that was cited for this KER description. More help

Ahmann FR, Garewal HS, Schifman R, Celniker A, Rodney S. 1987. Intracellular adenosine triphosphate as a measure of human tumor cell viability and drug modulated growth. In Vitro Cellular & Developmental Biology 23:474-480. DOI: 10.1007/BF02628417.

Bonora M, Patergnani S, Rimessi A, De Marchi E, Suski JM, Bononi A, Giorgi C, Marchi S, Missiroli S, Poletti F, Wieckowski MR, Pinton P. 2012. ATP synthesis and storage. Purinergic Signalling 8:343-357. DOI: 10.1007/s11302-012-9305-8.

Crouch SPM, Kozlowski R, Slater KJ, Fletcher J. 1993. The use of ATP bioluminescence as a measure of cell proliferation and cytotoxicity. Journal of Immunological Methods 160:81-88. DOI: https://doi.org/10.1016/0022-1759(93)90011-U.

Kingston RE, Narlikar GJ. 1999. ATP-dependent remodeling and acetylation as regulators of chromatin fluidity. Genes Dev 13:2339-2352. DOI: 10.1101/gad.13.18.2339.

Koczor CA, Shokolenko IN, Boyd AK, Balk SP, Wilson GL, Ledoux SP. 2009. Mitochondrial DNA damage initiates a cell cycle arrest by a Chk2-associated mechanism in mammalian cells. J Biol Chem 284:36191-36201. DOI: 10.1074/jbc.M109.036020.

Kuruvilla S, Qualls CW, Jr., Tyler RD, Witherspoon SM, Benavides GR, Yoon LW, Dold K, Brown RH, Sangiah S, Morgan KT. 2003. Effects of minimally toxic levels of carbonyl cyanide P-(trifluoromethoxy) phenylhydrazone (FCCP), elucidated through differential gene expression with biochemical and morphological correlations. Toxicol Sci 73:348-361. DOI: 10.1093/toxsci/kfg084.

Nieminen AL, Saylor AK, Herman B, Lemasters JJ. 1994. ATP depletion rather than mitochondrial depolarization mediates hepatocyte killing after metabolic inhibition. Am J Physiol 267:C67-74. DOI: 10.1152/ajpcell.1994.267.1.C67.

Sithara T, Arun KB, Syama HP, Reshmitha TR, Nisha P. 2017. Morin inhibits proliferation of SW480 colorectal cancer cells by inducing apoptosis mediated by reactive oxygen species formation and uncoupling of Warburg effect. Frontiers in Pharmacology 8. DOI: 10.3389/fphar.2017.00640.