Phenylbutyrate / PKM2 Cancer Research Results

PB, Phenylbutyrate: Click to Expand ⟱
Features:
Used to treat urea cycle disorders
Sodium phenylbutyrate helps remove ammonia from the body.
-Phenyl-butyrate (PB)4 is an aromatic fatty acid that is converted in vivo to phenylacetate (PA) by β-oxidation in liver and kidney mitochondria.
-In human body, phenylbutyrate is oxidized to phenylacetate, which is in turn conjugated with glutamine and eliminated in urine as phenylacetylglutamine, thereby mediating elimination of waste nitrogen
-Phenylbutyrate is one of the first drugs encountered in cancer therapy as a histone deacetylase inhibitor (HDACI) (relatively weak compared to vorinostat (SAHA), romidepsin, etc.).
-Butyric acid is one of the short-chain fatty acids produced by the gut microbiota through the fermentation of dietary fiber. Butyrate is primarily recognized for its beneficial effects in the colon and is tightly linked to gut health.
-Phenylbutyrate is a derivative of butyrate that has been chemically modified by the addition of a phenyl group. This structural change increases its lipophilicity (fat solubility) and alters its metabolic fate and biological activity. This allows it to be used as a systemic drug, in contrast to the locally produced butyrate in the gut, which is rapidly metabolized by colonocytes

Pathways:
-Histone deacetylase (HDAC) inhibitor
-ER stress inhibitor (at least in normal cell)
-Can act as a chemical chaperone, helping to reduce ER stress by facilitating proper protein folding.
-Modulation of NF-κB Signaling
-Changes in pathways such as PI3K/Akt/mTOR and MAPK.
-Some preclinical investigations have reported that treatment with phenylbutyrate leads to mitochondrial dysfunction and endoplasmic reticulum (ER) stress, both of which can result in an increase of ROS within cancer cells.

Note: Sodium butyrate (NaBu) vs Sodium phenylbutyrate
-Sodium butyrate is primarily a research tool with limited clinical application, whereas phenylbutyrate is used clinically
-Phenylbutyrate typically exhibits improved pharmacokinetics and is more amenable to systemic use compared to sodium butyrate.
-Both compounds act as HDAC inhibitors, phenylbutyrate additionally modulates ER stress and mitochondrial function, leading to potentially greater ROS production in certain cancer cells.

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Rank Pathway / Axis Cancer Context Normal Tissue Context TSF Primary Effect Notes
1 Histone Deacetylase (HDAC) inhibition Histone acetylation ↑; p21 ↑; differentiation ↑; proliferation ↓ Gene-expression modulation R, G Epigenetic reprogramming Core anticancer mechanism; early-generation, relatively weak HDAC inhibitor.
2 Cell-cycle arrest G1 arrest ↑; Cyclin D1 ↓ (reported) G Cytostasis Common downstream effect of HDAC inhibition.
3 Apoptosis Caspase activation ↑ (reported; model-dependent) G Cell death execution Often secondary to transcriptional changes and stress modulation.
4 ER stress / Chemical chaperone activity Context-dependent: ER stress ↑ or ↓ ER stress ↓ (protein misfolding disorders) R, G Protein-folding modulation Acts as chemical chaperone; effect depends on cell type and dose.
5 NF-κB signaling NF-κB modulation (reported) Inflammatory tone modulation R, G Transcriptional regulation Likely secondary to epigenetic changes.
6 PI3K → AKT / MAPK pathways Survival pathway modulation (reported; model-dependent) R, G Growth signaling modulation Downstream transcriptional effects rather than primary kinase inhibition.
7 Mitochondrial stress / ROS ROS modulation (context-dependent) P, R, G Metabolic adaptation Not a primary ROS-inducing agent; effects vary by tumor model.
8 Urea-cycle nitrogen scavenging (approved indication) Ammonia elimination ↑ (phenylacetylglutamine formation) Clinical metabolic role Primary approved medical use.


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⟱
2429- PB,    Impact of butyrate on PKM2 and HSP90β expression in human colon tissues of different transformation stages: a comparison of gene and protein data
- in-vitro, Colon, NA
PKM2↓, *HSP90↑, HSP90∅,

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,  

Protein Folding & ER Stress

HSP90∅, 1,  
Total Targets: 2

Pathway results for Effect on Normal Cells:


Protein Folding & ER Stress

HSP90↑, 1,  
Total Targets: 1

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#:15  Target#:772  State#:%  Dir#:1
wNotes=0 sortOrder:rid,rpid

 

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