Metformin / PKM2 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)
PKM2, Pyruvate Kinase, Muscle 2: Click to Expand ⟱
Source:
Type: enzyme
PKM2 (Pyruvate Kinase, Muscle 2) is an enzyme that plays a crucial role in glycolysis, the process by which cells convert glucose into energy. PKM2 is a key regulatory enzyme in the glycolytic pathway, and it is primarily expressed in various tissues, including muscle, brain, and cancer cells.
-C-myc is a common oncogene that enhances aerobic glycolysis in the cancer cells by transcriptionally activating GLUT1, HK2, PKM2 and LDH-A
-PKM2 has been shown to be overexpressed in many types of tumors, including breast, lung, and colon cancer. This overexpression may contribute to the development and progression of cancer by promoting glycolysis and energy production in cancer cells.
-inhibition of PKM2 may cause ATP depletion and inhibiting glycolysis.
-PK exists in four isoforms: PKM1, PKM2, PKR, and PKL
-PKM2 plays a role in the regulation of glucose metabolism in diabetes.
-PKM2 is involved in the regulation of cell proliferation, apoptosis, and autophagy.
– Pyruvate kinase catalyzes the final, rate-limiting step of glycolysis, converting phosphoenolpyruvate (PEP) to pyruvate with the production of ATP.
– The PKM2 isoform is uniquely regulated and can exist in both highly active tetrameric and less active dimeric forms.
– Cancer cells often favor the dimeric form of PKM2 to slow pyruvate production, thereby accumulating upstream glycolytic intermediates that can be diverted into anabolic pathways to support cell growth and proliferation.
– Under low oxygen conditions, cancer cells rely on altered metabolic pathways in which PKM2 is a key player. – The shift to aerobic glycolysis (Warburg effect) orchestrated in part by PKM2 helps tumor cells survive and grow in hypoxic conditions.

– Elevated expression of PKM2 is frequently observed in many cancer types, including lung, breast, colorectal, and pancreatic cancers.
– High levels of PKM2 are often correlated with enhanced tumor aggressiveness, poor differentiation, and advanced clinical stage.

PKM2 in carcinogenesis and oncotherapy

Inhibitors of PKM2:
-Shikonin, Resveratrol, Baicalein, EGCG, Apigenin, Curcumin, Ursolic Acid, Citrate (best known as an allosteric inhibitor of phosphofructokinase-1 (PFK-1), a key rate-limiting enzyme in glycolysis) potential to directly inhibit or modulate PKM2 is less well established

Full List of PKM2 inhibitors from Database
-key connected observations: Glycolysis↓, lactateProd↓, ROS↑ in cancer cell, while some result for opposite effect on normal cells.
Tumor pyruvate kinase M2 modulators

Flavonoids effect on PKM2
Compounds name IC50/AC50uM Effect
Flavonols
1. Fisetin 0.90uM Inhibition
2. Rutin 7.80uM Inhibition
3. Galangin 8.27uM Inhibition
4. Quercetin 9.24uM Inhibition
5. Kaempferol 9.88uM Inhibition
6. Morin hydrate 37.20uM Inhibition
7. Myricetin 0.51uM Activation
8. Quercetin 3-b- D-glucoside 1.34uM Activation
9. Quercetin 3-D -galactoside 27-107uM Ineffective
Flavanons
10. Neoeriocitrin 0.65uM Inhibition
11. Neohesperidin 14.20uM Inhibition
12. Naringin 16.60uM Inhibition
13. Hesperidin 17.30uM Inhibition
14. Hesperitin 29.10uM Inhibition
15. Naringenin 70.80uM Activation
Flavanonols
16. (-)-Catechin gallateuM 0.85 Inhibition
17. (±)-Taxifolin 1.16uM Inhibition
18. (-)-Epicatechin 1.33uM Inhibition
19. (+)-Gallocatechin 4-16uM Ineffective
Phenolic acids
20. Ferulic 11.4uM Inhibition
21. Syringic and 13.8uM Inhibition
22. Caffeic acid 36.3uM Inhibition
23. 3,4-Dihydroxybenzoic acid 78.7uM Inhibition
24. Gallic acid 332.6uM Inhibition
25. Shikimic acid 990uM Inhibition
26. p-Coumaric acid 22.2uM Activation
27. Sinapinic acids 26.2uM Activation
28. Vanillic 607.9uM Activation


Scientific Papers found: Click to Expand⟱
1640- CA,  MET,    Caffeic Acid Targets AMPK Signaling and Regulates Tricarboxylic Acid Cycle Anaplerosis while Metformin Downregulates HIF-1α-Induced Glycolytic Enzymes in Human Cervical Squamous Cell Carcinoma Lines
- in-vitro, Cerv, SiHa
GLS↓, NADPH↓, ROS↑, TumCD↑, AMPK↑, Hif1a↓, GLUT1↓, GLUT3↓, HK2↓, PFK↓, PKM2↓, LDH↓, cMyc↓, BAX↓, cycD1/CCND1↓, PDH↓, ROS↑, Apoptosis↑, eff↑, ACLY↓, FASN↓, Bcl-2↓, Glycolysis↓,
2387- MET,  GEM,    Metformin Increases the Response of Cholangiocarcinoma Cells to Gemcitabine by Suppressing Pyruvate Kinase M2 to Activate Mitochondrial Apoptosis
- in-vitro, CCA, HCC9810
eff↑, tumCV↓, TumCMig↓, TumCI↓, Apoptosis↑, PKM2↓, PDHB↓,
2386- MET,    Mechanisms of metformin inhibiting cancer invasion and migration
- Review, Var, NA
OS↑, AMPK↑, EMT↓, TGF-β↓, mTOR↓, P70S6K↓, PKM2↓, Hif1a↓, ChemoSen↑,
2385- MET,    Metformin activates chaperone-mediated autophagy and improves disease pathologies in an Alzheimer disease mouse model
- in-vitro, AD, H4 - in-vitro, NA, HEK293 - in-vivo, NA, NA - in-vitro, NA, SH-SY5Y
*HK2↓, *PKM2↓, *Dose↝, IKKα↑, memory↑, p‑Hsc70↑, APP↓,
2384- MET,    Integration of metabolomics and transcriptomics reveals metformin suppresses thyroid cancer progression via inhibiting glycolysis and restraining DNA replication
- in-vitro, Thyroid, BCPAP - in-vivo, NA, NA - in-vitro, Thyroid, TPC-1
Glycolysis↓, OXPHOS↑, tumCV↓, TumCI↓, TumCMig↓, EMT↓, Apoptosis↑, TumCCA↑, LDHA↓, PKM2↓, IDH1↑, TumCG↓,
2379- MET,    Down‐regulation of PKM2 enhances anticancer efficiency of THP on bladder cancer
- in-vitro, Bladder, T24/HTB-9 - in-vitro, BC, UMUC3
PKM2↓, p‑STAT3↓, TumCG↓, eff↑, chemoP↑, AMPK↑,
2378- MET,    Metformin inhibits epithelial-mesenchymal transition of oral squamous cell carcinoma via the mTOR/HIF-1α/PKM2/STAT3 pathway
- in-vitro, SCC, CAL27 - in-vivo, NA, NA
TumCP↓, TumCMig↓, TumCI↓, EMT↓, mTOR↓, Hif1a↓, PKM2↓, STAT3↓, E-cadherin↑, Vim↓, Snail↓, STAT3↓,
2377- MET,    Metformin Inhibits TGF-β1-Induced Epithelial-to-Mesenchymal Transition via PKM2 Relative-mTOR/p70s6k Signaling Pathway in Cervical Carcinoma Cells
- in-vitro, Cerv, HeLa - in-vitro, Cerv, SiHa
EMT↓, P70S6K↓, mTOR↓, PKM2↓, Warburg↓, AMPK↑,
2376- MET,    Metformin Inhibits Epithelial-to-Mesenchymal Transition of Keloid Fibroblasts via the HIF-1α/PKM2 Signaling Pathway
- in-vitro, Nor, NA
*Hif1a↓, *EMT↓, *p‑P70S6K↓, *PKM2↓,
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↓,
2371- MET,    The role of pyruvate kinase M2 in anticancer therapeutic treatments
- Review, Var, NA
ChemoSen↑, PKM2↓, Hif1a↓, EMT↓,

Showing Research Papers: 1 to 12 of 12

* indicates research on normal cells as opposed to diseased cells
Total Research Paper Matches: 12

Pathway results for Effect on Cancer / Diseased Cells:


Redox & Oxidative Stress ⓘ

OXPHOS↑, 1,   ROS↑, 2,  

Core Metabolism/Glycolysis ⓘ

ACLY↓, 1,   AMPK↑, 4,   cMyc↓, 1,   FASN↓, 1,   GLS↓, 1,   Glycolysis↓, 3,   HK2↓, 1,   IDH1↑, 1,   LDH↓, 1,   LDHA↓, 1,   NADPH↓, 1,   PDH↓, 1,   PDHB↓, 1,   PFK↓, 1,   PKM2↓, 10,   Warburg↓, 1,  

Cell Death ⓘ

Akt↓, 1,   Apoptosis↑, 5,   BAX↓, 1,   Bcl-2↓, 1,   TumCD↑, 1,  

Transcription & Epigenetics ⓘ

tumCV↓, 3,  

Protein Folding & ER Stress ⓘ

p‑Hsc70↑, 1,  

DNA Damage & Repair ⓘ

PARP↓, 2,  

Cell Cycle & Senescence ⓘ

cycD1/CCND1↓, 1,   TumCCA↑, 1,  

Proliferation, Differentiation & Cell State ⓘ

EMT↓, 5,   mTOR↓, 4,   P70S6K↓, 2,   PI3K↓, 1,   STAT3↓, 2,   p‑STAT3↓, 1,   TumCG↓, 2,  

Migration ⓘ

APP↓, 1,   E-cadherin↑, 1,   Snail↓, 1,   TGF-β↓, 1,   TumCI↓, 4,   TumCMig↓, 4,   TumCP↓, 1,   Vim↓, 1,  

Angiogenesis & Vasculature ⓘ

Hif1a↓, 5,  

Barriers & Transport ⓘ

GLUT1↓, 1,   GLUT3↓, 1,  

Immune & Inflammatory Signaling ⓘ

COX2↓, 1,   IKKα↑, 1,  

Drug Metabolism & Resistance ⓘ

ChemoSen↑, 2,   eff↑, 4,  

Clinical Biomarkers ⓘ

LDH↓, 1,  

Functional Outcomes ⓘ

chemoP↑, 1,   memory↑, 1,   OS↑, 1,  
Total Targets: 54

Pathway results for Effect on Normal Cells:


Core Metabolism/Glycolysis ⓘ

HK2↓, 1,   PKM2↓, 2,  

Proliferation, Differentiation & Cell State ⓘ

EMT↓, 1,   p‑P70S6K↓, 1,  

Angiogenesis & Vasculature ⓘ

Hif1a↓, 1,  

Drug Metabolism & Resistance ⓘ

Dose↝, 1,  
Total Targets: 6

Scientific Paper Hit Count for: PKM2, Pyruvate Kinase, Muscle 2
12 Metformin
1 Caffeic acid
1 Gemcitabine (Gemzar)
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#:772  State#:%  Dir#:1
  wNotes=0  sortOrder:rid,rpid

 

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