Bax/Bak LOF abolishes FOXO4-DRI kill like navitoclax
STATUS_LABEL: NEGATIVE
Claim
On a matched senescent culture, Bax/Bak loss-of-function (or BAX-channel blockade) abolishes FOXO4-DRI senescent-cell kill at least as much as it abolishes navitoclax kill — pre-registered relative kill loss_FOXO4 ≥ relative kill loss_navitoclax, with each arm showing a pre-registered ≥20% relative kill loss vs the same senolytic on control genotype / vehicle.
Why it matters
P5 hoped distinct FOXO4–p53 entry would spare FOXO4-DRI from MOMP-gated interference. P6 asked HN equal-blunt plus optional Bax epistasis; it left Bax/Bak necessity UNKNOWN and is not proof of this gate. Soft-claims: discussion — matched Bax/Bak LOF FOXO4-DRI vs navitoclax epistasis remains UNKNOWN (soft-complete 0).
Mechanism sketch
FOXO4-DRI enters via FOXO4–p53; navitoclax via Bcl-2/Bcl-xL/Bcl-w; both may still require Bax/Bak MOMP for execution. Endothelial FOXO4-DRI work frames a p53 / BCL-2 / Caspase-3 cascade — Bcl-2-family nodes can sit downstream without proving Bax/Bak necessity. Humanin–Bax MOMP block is mechanism prior for pharmacologic BAX-channel interference, not a FOXO4-DRI epistasis result. Assumption-kill: if FOXO4-DRI still needs Bax/Bak, distinct entry does not spare MOMP-gated interference; ≥ equal abolish is stronger than “both use mitochondria.”
Prior art
- PMID 28340339 / DOI 10.1016/j.cell.2017.02.031 / PMC5556182 — FOXO4-DRI perturbs FOXO4–p53 → senescent-cell apoptosis (Baar 2017); not Bcl-xL occupancy; no Bax/Bak LOF arm.
- PMID 41625068 / DOI 10.3389/fbioe.2025.1729166 / PMC12852416 — endothelial FOXO4-DRI framed via p53 / BCL-2 / Caspase-3 (2025); not Bax/Bak DKO epistasis.
- PMID 26711051 / DOI 10.1111/acel.12445 / PMC4854923 — navitoclax senolytic via Bcl-2 / Bcl-xL / Bcl-w; cell-type restricted (Zhu 2016).
- PMID 12732850 / DOI 10.1038/nature01627 — humanin binds Bax; blocks mitochondrial translocation / cytochrome c release (Guo 2003) — MOMP-block prior, not FOXO4-DRI epistasis.
Baseline claimed
Distinct FOXO4–p53 entry means FOXO4-DRI SC kill need not share Bax/Bak necessity with navitoclax, or P6’s shared-MOMP caveat already settles the epistasis.
Baseline measured
FOXO4–p53 entry LITERATURE (PMID 28340339). Downstream BCL-2/caspase framing LITERATURE without Bax/Bak LOF (PMID 41625068). Navitoclax Bcl-2-family senolytic LITERATURE (PMID 26711051). HN–Bax MOMP block LITERATURE as mechanism prior (PMID 12732850). FOXO4-DRI∩Bax/Bak knockout/epistasis soft-complete 0; FOXO4-DRI∩(cytochrome c|MOMP) soft-complete 0; matched Bax/Bak LOF × FOXO4-DRI vs navitoclax UNKNOWN. ≥ equal abolish (loss_FOXO4 ≥ loss_nav; each ≥20% relative) PREDICTION. P6 does not already prove this epistasis.
Actionable limitations
- Do not treat P6 as proving P7 — P6 left Bax epistasis UNKNOWN and used HN equal-blunt as a separate PREDICTION; it did not run Bax/Bak LOF.
- BCL-2 cascade language ≠ Bax requirement — 41625068 is not a Bax/Bak LOF kill of FOXO4-DRI.
- ≥ equal abolish is stronger than shared mitochondrial involvement — FOXO4-DRI could keep partial Bax-independent death routes; navitoclax-insensitive SC types confound matched culture choice.
Method
propose-assay
Prediction variables
| name | kind | assay | threshold |
|---|---|---|---|
| FOXO4_DRI_p53_entry | LITERATURE | FOXO4 peptide disrupts FOXO4–p53 in senescent cells → apoptosis (Baar 2017) | FOXO4–p53 axis entry, not Bcl-xL occupancy (PMID 28340339) |
| FOXO4_DRI_p53_BCL2_Caspase3_framing | LITERATURE | Senescent endothelium FOXO4-DRI via p53/BCL-2/Caspase-3 (2025) | mitochondrial Bcl-2-family nodes may sit downstream (PMID 41625068) — not Bax/Bak epistasis |
| navitoclax_Bcl2_family_senolytic | LITERATURE | ABT-263 senolysis in restricted SC panels (Zhu 2016) | Bcl-2/Bcl-xL/Bcl-w dependent; cell-type restricted (PMID 26711051) |
| HN_Bax_MOMP_block_mechanism_prior | LITERATURE | HN–Bax binding; blocks Bax mitochondrial translocation / cytochrome c (Guo 2003) | MOMP / cytochrome c suppression (PMID 12732850) — prior for BAX-channel tools; not FOXO4-DRI epistasis; no KD invented |
| matched_BaxBak_LOF_FOXO4_vs_navitoclax_panel | UNKNOWN | Same senescent culture — FOXO4-DRI vs navitoclax under Bax/Bak LOF or BAX-channel block vs control; viability + cytochrome-c/MOMP marker | dedicated matched epistasis panel not found (soft-complete 0) — UNKNOWN |
| FOXO4_abolish_ge_navitoclax_under_BaxBak_LOF | PREDICTION | Pre-registered matched culture; relative kill loss under Bax/Bak LOF or BAX-channel block for each senolytic vs control | relative kill loss_FOXO4 ≥ relative kill loss_navitoclax AND each arm ≥20% relative kill loss (α/N pre-specified) — do not invent observed % or dosing |
Ablate
- remove matched Bax/Bak LOF (or BAX-channel block) contrast of FOXO4-DRI vs navitoclax on the same culture: Without the H2H epistasis panel, separate LITERATURE legs cannot show FOXO4-DRI kill is abolished ≥ navitoclax under Bax/Bak LOF.
- remove ≥ equal-abolish quantitative contrast (loss_FOXO4 ≥ loss_nav): Showing both need mitochondria is weaker than the claim; FOXO4-DRI could retain partial Bax-independent routes while still “using MOMP.”
- remove P6≠proof + BCL-2-framing≠Bax-requirement discipline: Treating P6 or 41625068 cascade language as already deciding Bax epistasis would invent a LOF result left UNKNOWN.
Refute if
On the pre-registered matched panel, FOXO4-DRI kill largely survives Bax/Bak LOF / BAX-channel block while navitoclax kill is abolished, or relative kill loss_FOXO4 is below relative kill loss_navitoclax outside the pre-registered ≥ equal band — pathway-sparing / Bax-independent FOXO4-DRI execution survives.
Ask a human
Lock one senescent system sensitive to both senolytics, Bax/Bak LOF vs BAX-channel-block tool, and viability + cytochrome-c readout before claiming ≥ equal abolish; do not treat P6 as proof; no dosing.
Cheap IP
kill_cost_tier=1 · time_to_refute=4w · ip_class=momp-execution-gate · vault_hold=no
Execution
execution_status=NOT_RUN · fto_status=UNKNOWN · related_prior=P6 (not proof of Bax/Bak epistasis)