| Rank |
Pathway / Axis |
Cancer / Tumor Context |
Normal Tissue Context |
TSF |
Primary Effect |
Notes / Interpretation |
| 1 |
Mitochondrial Complex I (OXPHOS) inhibition |
Energetic stress ↑; proliferation pressure ↓ (context) |
Hepatic energy shift; gluconeogenesis ↓ |
P, R |
Bioenergetic modulation |
Metformin partially inhibits mitochondrial Complex I (OXPHOS), increasing AMP/ADP ratio and triggering downstream AMPK activation. ROS changes are dose- and context-dependent. |
| 2 |
AMPK activation (LKB1/AMPK axis) |
Growth programs ↓ (context-dependent) |
Metabolic homeostasis ↑ |
R |
Energy-sensor activation |
AMPK activation is frequently invoked downstream of respiratory inhibition, though some hepatic effects can be AMPK-independent. |
| 3 |
mTORC1 inhibition (via AMPK→TSC2/Raptor; also AMPK-independent routes reported) |
Protein synthesis / growth signaling ↓ (reported) |
Reduced anabolic signaling in liver (context) |
R, G |
Anti-anabolic signaling |
Mechanistically supported: AMPK regulation of TSC2 and Raptor contributes to metformin-mediated mTORC1 inhibition; AMPK-independent mTORC1 inhibition has also been described. |
| 4 |
Hepatic gluconeogenesis suppression |
Indirect tumor support via insulin/IGF-1 lowering (systemic) |
Liver glucose production ↓ (core clinical effect) |
R, G |
Systemic metabolic effect |
Metformin reduces hepatic glucose output through multiple mechanisms (energy state shifts, cAMP pathways, and other proposed nodes). |
| 5 |
Insulin / IGF-1 axis (systemic growth signaling) |
Mitogenic tone ↓ (context; strongest in hyperinsulinemic settings) |
Insulin sensitivity ↑; insulin levels ↓ (context) |
G |
Systemic growth-factor modulation |
Many “anti-cancer” hypotheses depend on lowering insulin/IGF-1 signaling rather than direct tumor cytotoxicity. |
| 6 |
Cell-cycle & apoptosis (secondary, model-dependent) |
Proliferation ↓; apoptosis ↑ (reported in some models) |
↔ |
G |
Conditional cytostasis |
Often downstream of mTORC1 suppression/energy stress; not a universal direct cytotoxin signature. |
| 7 |
Inflammation signaling (NF-κB and related programs) |
Inflammatory pro-survival transcription ↓ (reported) |
Anti-inflammatory trends in metabolic disease contexts |
R, G |
Inflammation modulation |
Frequently reported as downstream of improved metabolic/oxidative stress tone; avoid presenting as a primary direct target. |
| 8 |
Autophagy / stress adaptation |
Autophagy ↑ or ↓ depending on context; can affect therapy response |
↔ |
G |
Adaptive stress response |
Autophagy findings are heterogeneous across tumor models and combinations. |
| 9 |
Clinical oncology evidence (adjunct use) |
Observational signals exist; randomized data are mixed |
— |
— |
Translation constraint |
Epidemiology/meta-analyses suggested potential benefit in some cancers, but large randomized trials (e.g., adjuvant breast cancer MA.32) did not show broad benefit across the overall population. |
| 10 |
Safety / monitoring constraints (B12, lactic acidosis risk in predisposed states) |
— |
Vitamin B12 deficiency risk with long-term use; rare lactic acidosis risk increases with renal impairment and other conditions |
— |
Clinical risk management |
Long-term B12 monitoring is commonly advised; prescribing requires renal function assessment due to lactic acidosis risk in predisposed settings. |