Metformin / PARP Cancer Research Results

MET, Metformin: Click to Expand ⟱
Features: oral antidiabetic agent,
Metformin is a pleiotropic drug: attributed to its action on AMPK
Metformin is a biguanide drug used primarily for type 2 diabetes. Mechanistically, it is best described as a bioenergetic modulator: partial inhibition of mitochondrial respiration can raise AMP/ADP, engage AMPK, and suppress mTORC1 signaling; systemically it reduces hepatic gluconeogenesis and can lower insulin/IGF-1 growth signaling. In oncology, observational studies suggested improved outcomes in some settings, but randomized trial data are mixed (e.g., large adjuvant breast cancer data did not show broad benefit overall). Long-term use can be associated with vitamin B12 deficiency, and prescribing requires attention to renal function due to rare lactic acidosis risk in predisposed states.
Metformin directly(partially) inhibits Complex I of the electron transport chain (ETC) in mitochondria. This inhibition decreases mitochondrial ATP production and forces cells to rely more on glycolysis for energy.
Cancer cells, especially those with high energy demands, may be particularly sensitive to a drop in ATP levels. The inhibition of Complex I also increases the AMP/ATP ratio, setting the stage for the activation of downstream energy stress pathways.
AMPK activation results in the inhibition of the mammalian target of rapamycin (mTOR) pathway, a central regulator of protein synthesis and cellular growth. mTOR inhibition reduces cell proliferation and limits tissue growth, which can slow tumor progression.

Metformin reduces circulating insulin levels, which in turn can decrease the activation of the insulin and insulin-like growth factor-1 (IGF-1) receptor pathways.

ETC Inhibitors: Drugs that directly inhibit specific ETC complexes (e.g., Complex I inhibitors like metformin or phenformin) can increase electron leakage and ROS production.(dose- and context-dependent, and not consistent)

-known as mild OXPHOS inhibitor(Complex I modulator)

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.

Time-Scale Flag (TSF): P / R / G

  • P: 0–30 min (rapid bioenergetic effects)
  • R: 30 min–3 hr (acute signaling shifts: AMPK/mTOR)
  • G: >3 hr (gene-regulatory adaptation and phenotype outcomes)
PARP, poly ADP-ribose polymerase (PARP) cleavage: Click to Expand ⟱
Source:
Type:
Poly (ADP-ribose) polymerase (PARP) cleavage is a hallmark of caspase activation. PARP (Poly (ADP-ribose) polymerase) is a family of proteins involved in a variety of cellular processes, including DNA repair, genomic stability, and programmed cell death. PARP enzymes play a crucial role in repairing single-strand breaks in DNA.
PARP has gained significant attention, particularly in the treatment of certain types of tumors, such as those with BRCA1 or BRCA2 mutations. These mutations impair the cell's ability to repair double-strand breaks in DNA through homologous recombination. Cancer cells with these mutations can become reliant on PARP for survival, making them particularly sensitive to PARP inhibitors.
PARP inhibitors, such as olaparib, rucaparib, and niraparib, have been developed as targeted therapies for cancers associated with BRCA mutations.

PARP Family:
The poly (ADP-ribose) polymerases (PARPs) are a family of enzymes involved in a number of cellular processes, including DNA repair, genomic stability, and programmed cell death.
PARP1 is the predominant family member responsible for detecting DNA strand breaks and initiating repair processes, especially through base excision repair (BER).

PARP1 Overexpression:
In several cancer types—including breast, ovarian, prostate, and lung cancers—elevated PARP1 expression and/or activity has been reported.
High PARP1 expression in certain cancers has been associated with aggressive tumor behavior and resistance to therapies (especially those that induce DNA damage).
Increased PARP1 activity may correlate with poorer overall survival in tumors that rely on DNA repair for survival.
Scientific Papers found: Click to Expand⟱
1563- Api,  MET,    Metformin-induced ROS upregulation as amplified by apigenin causes profound anticancer activity while sparing normal cells
- in-vitro, Nor, HDFa - in-vitro, PC, AsPC-1 - in-vitro, PC, MIA PaCa-2 - in-vitro, Pca, DU145 - in-vitro, Pca, LNCaP - in-vivo, NA, NA
selectivity↑, selectivity↑, selectivity↓, ROS↑, eff↑, tumCV↓, MMP↓, Dose∅, eff↓, DNAdam↑, Apoptosis↑, TumAuto↑, Necroptosis↑, p‑P53↑, BIM↑, BAX↑, p‑PARP↑, Casp3↑, Casp8↑, Casp9↑, Cyt‑c↑, Bcl-2↓, AIF↑, p62↑, LC3B↑, MLKL↑, p‑MLKL↓, RIP3↑, p‑RIP3↑, TumCG↑, TumW↓,
1864- DCA,  MET,    Dichloroacetate Enhances Apoptotic Cell Death via Oxidative Damage and Attenuates Lactate Production in Metformin-Treated Breast Cancer Cells
- in-vitro, BC, MCF-7 - in-vitro, BC, T47D - in-vitro, Nor, MCF10
PDKs↓, eff↑, ROS↑, PDK1↓, lactateProd↓, p‑PDH↑, Dose∅, OCR↑, DNA-PK↑, γH2AX↑, cl‑PARP↑, selectivity↑, *toxicity∅,
1154- HNK,  MET,    Honokiol inhibits the growth of hormone-resistant breast cancer cells: its promising effect in combination with metformin
- in-vitro, BC, MCF-7 - in-vitro, BC, SkBr3 - in-vitro, BC, MDA-MB-231
cl‑PARP↑, Bcl-2↓, ERα/ESR1↓,
2375- MET,    Metformin inhibits gastric cancer via the inhibition of HIF1α/PKM2 signaling
- in-vitro, GC, SGC-7901
tumCV↓, TumCI↓, TumCMig↓, Apoptosis↑, PARP↓, PI3K↓, Akt↓, Hif1a↓, PKM2↓, COX2↓,
2374- MET,    Metformin Induces Apoptosis and Downregulates Pyruvate Kinase M2 in Breast Cancer Cells Only When Grown in Nutrient-Poor Conditions
- in-vitro, BC, MCF-7 - in-vitro, BC, SkBr3 - in-vitro, BC, MDA-MB-231
eff↑, Apoptosis↑, Glycolysis↓, PKM2↓, mTOR↓, PARP↓,

Showing Research Papers: 1 to 5 of 5

* indicates research on normal cells as opposed to diseased cells
Total Research Paper Matches: 5

Pathway results for Effect on Cancer / Diseased Cells:


Redox & Oxidative Stress ⓘ

ROS↑, 2,  

Mitochondria & Bioenergetics ⓘ

AIF↑, 1,   MMP↓, 1,   OCR↑, 1,  

Core Metabolism/Glycolysis ⓘ

Glycolysis↓, 1,   lactateProd↓, 1,   p‑PDH↑, 1,   PDK1↓, 1,   PDKs↓, 1,   PKM2↓, 2,  

Cell Death ⓘ

Akt↓, 1,   Apoptosis↑, 3,   BAX↑, 1,   Bcl-2↓, 2,   BIM↑, 1,   Casp3↑, 1,   Casp8↑, 1,   Casp9↑, 1,   Cyt‑c↑, 1,   MLKL↑, 1,   p‑MLKL↓, 1,   Necroptosis↑, 1,  

Transcription & Epigenetics ⓘ

tumCV↓, 2,  

Autophagy & Lysosomes ⓘ

LC3B↑, 1,   p62↑, 1,   TumAuto↑, 1,  

DNA Damage & Repair ⓘ

DNA-PK↑, 1,   DNAdam↑, 1,   p‑P53↑, 1,   PARP↓, 2,   p‑PARP↑, 1,   cl‑PARP↑, 2,   γH2AX↑, 1,  

Proliferation, Differentiation & Cell State ⓘ

mTOR↓, 1,   PI3K↓, 1,   TumCG↑, 1,  

Migration ⓘ

RIP3↑, 1,   p‑RIP3↑, 1,   TumCI↓, 1,   TumCMig↓, 1,  

Angiogenesis & Vasculature ⓘ

Hif1a↓, 1,  

Immune & Inflammatory Signaling ⓘ

COX2↓, 1,  

Hormonal & Nuclear Receptors ⓘ

ERα/ESR1↓, 1,  

Drug Metabolism & Resistance ⓘ

Dose∅, 2,   eff↓, 1,   eff↑, 3,   selectivity↓, 1,   selectivity↑, 3,  

Clinical Biomarkers ⓘ

ERα/ESR1↓, 1,  

Functional Outcomes ⓘ

TumW↓, 1,  
Total Targets: 50

Pathway results for Effect on Normal Cells:


Functional Outcomes ⓘ

toxicity∅, 1,  
Total Targets: 1

Scientific Paper Hit Count for: PARP, poly ADP-ribose polymerase (PARP) cleavage
5 Metformin
1 Apigenin (mainly Parsley)
1 Dichloroacetate
1 Honokiol
Query results interpretion may depend on "conditions" listed in the research papers.
Such Conditions may include : 
  -low or high Dose
  -format for product, such as nano of lipid formations
  -different cell line effects
  -synergies with other products 
  -if effect was for normal or cancerous cells

Filter Conditions: Pro/AntiFlg:%  IllCat:%  CanType:%  Cells:%  prod#:11  Target#:239  State#:%  Dir#:%
  wNotes=0  sortOrder:rid,rpid

 

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