Butyrate / PKM2 Cancer Research Results

Buty, Butyrate: Click to Expand ⟱
Features:

Butyrate — a four-carbon short-chain fatty acid produced mainly by gut microbial fermentation of dietary fiber, functioning as both a colonocyte energy substrate and a pleiotropic signaling metabolite. It is formally classified as an endogenous microbial metabolite and short-chain fatty acid; common research and delivery forms include sodium butyrate and the oral prodrug tributyrin. Standard abbreviations include butyrate, NaBu, SCFA, and TB for tributyrin. Its source is primarily the colonic microbiome–fiber axis, with highest physiological relevance in the colon lumen and colonic epithelium rather than in systemic circulation. In cancer biology, its effects are highly context-dependent: it is most mechanistically credible in colorectal and inflammation-linked gastrointestinal settings, while newer tumor-microbiome data indicate that intratumoral butyrate can also support progression in some non-colorectal contexts.

Butyric acid primarily exerts its anticancer properties through two mechanisms:
(i) Activation of cell-surface receptors (GPR41, GPR43 and HCAR2/GPR109A)
(ii) inhibition of HDACs in different cells.

butyrate paradox: butyrate promotes proliferation of normal colonocytes, it has the opposite effect on cancerous cells where it inhibits cell proliferation and also induces apoptosis

Primary mechanisms (ranked):

  1. HDAC inhibition with histone hyperacetylation, driving differentiation, cell-cycle arrest, apoptosis, and altered immune-regulatory transcription.
  2. Warburg-dependent metabolic partitioning (“butyrate paradox”), in which normal colonocytes oxidize butyrate as fuel whereas glycolytic colorectal cancer cells accumulate it and become more HDAC-inhibition-sensitive.
  3. GPCR signaling through HCAR2 GPR109A, FFAR2 GPR43, and FFAR3 GPR41, shaping epithelial barrier function, inflammasome and IL-18 programs, and immune tone.
  4. Secondary metabolic reprogramming, including suppression of glycolytic dependence in some colorectal cancer models.
  5. Context-dependent modulation of inflammatory signaling, autophagy, and oxidative-stress handling.

Bioavailability / PK relevance: Butyrate is rapidly absorbed and extensively metabolized, so systemic exposure is limited and transient. Physiologic and therapeutic relevance is therefore mainly local to the colon; oral strategies that matter most are colonic-release sodium butyrate, microbiome/fiber approaches, or tributyrin-type prodrugs that improve delivery.

In-vitro vs systemic exposure relevance: Many cancer-cell studies use roughly 0.5–5 mM, with some using higher concentrations. Those ranges are plausible in the colonic lumen and at the epithelial interface, where butyrate commonly reaches about 10–20 mM, but they are generally not representative of sustained plasma exposure after ordinary oral dosing.

Clinical evidence status: Preclinical for direct anticancer efficacy; small early-phase human oncology studies exist for tributyrin and other butyrate-delivery approaches, but no established antitumor standard-of-care role is supported. Human evidence is stronger for GI-supportive or radiotherapy-supportive use than for tumor control.

Butyrate mechanistic matrix

Rank Pathway / Axis Cancer Cells Normal Cells TSF Primary Effect Notes / Interpretation
1 HDAC inhibition and histone acetylation programs ↑ histone acetylation; ↓ proliferation; ↑ differentiation; ↑ apoptosis ↑ histone acetylation with predominantly homeostatic and anti-inflammatory effects R→G Epigenetic reprogramming Most central direct mechanism, especially when intracellular butyrate accumulates beyond oxidative disposal capacity.
2 Warburg-dependent fuel versus accumulation axis ↓ butyrate oxidation in glycolytic CRC models → ↑ intracellular butyrate → stronger HDACi phenotype ↑ butyrate oxidation as mitochondrial fuel in differentiated colonocytes R Context-selective anticancer leverage This “butyrate paradox” is the key framework explaining why butyrate can support normal colon epithelium yet inhibit many colorectal cancer cells.
3 HCAR2 GPR109A and FFAR2 FFAR3 receptor signaling ↓ pro-tumor inflammation; ↑ apoptosis in receptor-competent contexts ↑ barrier support; ↑ epithelial repair signaling; ↑ immune homeostasis P→R Receptor-mediated epithelial and immune regulation Mechanistically meaningful but usually secondary to HDAC biology in direct cancer-cell systems; more important in mucosal and microenvironmental settings.
4 IL-18 inflammasome-linked mucosal defense axis ↔ or ↓ inflammation-associated carcinogenic signaling ↑ IL-18 and mucosal defense programs R→G Barrier and immune surveillance support Most relevant to inflammation-linked colorectal carcinogenesis rather than broad pan-cancer cytotoxicity.
5 Glycolysis and glucose-use reprogramming ↓ glycolytic dependence; ↓ Warburg phenotype (model-dependent) ↔ or ↑ oxidative utilization of butyrate R→G Metabolic normalization in subset models Best supported in colorectal systems; not a universal butyrate effect across all tumors.
6 NF-κB and inflammatory signaling ↓ inflammatory and immunosuppressive signaling (context-dependent) ↓ inflammatory tone P→R Microenvironmental anti-inflammatory effect Often relevant in IBD-CRC and GI-supportive settings; should not be overinterpreted as a stand-alone tumoricidal mechanism.
7 Mitochondrial ROS increase (secondary) ↔ or ↑ ROS and apoptosis signaling (high concentration only; model-dependent) ↔ or ↓ oxidative stress indirectly via barrier and inflammatory control R Stress-amplified apoptosis in subset models ROS is usually downstream and secondary, not a core primary mechanism of butyrate action.
8 NRF2 adaptive antioxidant signaling (secondary) ↔ (context-dependent) ↔ or ↑ cytoprotective adaptation G Stress adaptation NRF2 is not a canonical primary axis for butyrate and should remain secondary unless a model directly demonstrates it.
9 Autophagy and apoptosis coupling ↑ autophagy or apoptosis depending on model and dose ↔ R→G Cell-fate modulation Seen in some bladder and colorectal systems, but not central enough to outrank HDAC and metabolic axes.
10 Metastatic microenvironment context dependence ↔ or ↑ progression in some intratumoral-microbiome settings ↔ G Context-dependent risk constraint Recent evidence shows intratumor microbiome-derived butyrate can promote metastasis in some lung cancer settings, so butyrate should not be treated as uniformly antitumor.
11 Clinical Translation Constraint Rapid absorption and metabolism limit sustained systemic exposure; strongest rationale is colon-local delivery, microbiome/fiber modulation, or prodrug approaches. Human oncology evidence remains early-phase or supportive-care oriented rather than definitive for tumor control. — PK / Delivery / Evidence Important final constraint row because many in-vitro concentrations are colon-local rather than systemically achievable.

TSF legend: P: 0–30 min (primary/rapid effects) | R: 30 min–3 hr (acute signaling + stress responses) | G: >3 hr (gene-regulatory adaptation; 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⟱
5737- Buty,    Butyrate Suppresses the Proliferation of Colorectal Cancer Cells via Targeting Pyruvate Kinase M2 and Metabolic Reprogramming
- in-vitro, CRC, HCT116
HDAC↓, TumCP↓, PKM2↑, Warburg↓,

Showing Research Papers: 1 to 1 of 1

* indicates research on normal cells as opposed to diseased cells
Total Research Paper Matches: 1

Pathway results for Effect on Cancer / Diseased Cells:


Core Metabolism/Glycolysis ⓘ

PKM2↑, 1,   Warburg↓, 1,  

Proliferation, Differentiation & Cell State ⓘ

HDAC↓, 1,  

Migration ⓘ

TumCP↓, 1,  
Total Targets: 4

Pathway results for Effect on Normal Cells:


Total Targets: 0

Scientific Paper Hit Count for: PKM2, Pyruvate Kinase, Muscle 2
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#:50  Target#:772  State#:%  Dir#:%
  wNotes=0  sortOrder:rid,rpid

 

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