Gemcitabine (Gemzar) / PKM2 Cancer Research Results

GEM, Gemcitabine (Gemzar): Click to Expand ⟱
Features: Chemo
GEM An IV antimetabolic antineoplastic used with cisplatin for inoperable non-small cell lung CA
Treats cancer of pancreas, lung, ovary and breast.

Rank Pathway / Axis Cancer Cells Normal Cells TSF Primary Effect Notes / Interpretation
1 Inhibition of DNA synthesis (antimetabolite effect) Incorporated into DNA → chain termination Normal dividing cells affected (bone marrow, GI epithelium) P, R, G Direct cytotoxicity Gemcitabine (2′,2′-difluorodeoxycytidine, dFdC) is phosphorylated to the triphosphate form (dFdCTP) which competes with dCTP, gets incorporated into DNA, and blocks DNA chain elongation.
2 Ribonucleotide reductase (RNR) inhibition dFdCDP inhibits RNR → deoxynucleotide pool depletion ↔ (normal proliferating cells also impacted) R, G Nucleotide pool imbalance Gemcitabine diphosphate (dFdCDP) inhibits RNR, reducing available dNTPs and enhancing the chain-termination effect.
3 Apoptosis induction (DNA damage response) DNA damage signaling → caspase activation Toxicity in dividing normal tissues G Execution of cell death Prolonged DNA synthesis arrest and replication stress triggers apoptosis pathways via ATR/Chk1, p53, and caspase cascades.
4 Cell-cycle arrest (S-phase accumulation) S-phase arrest steers cells into apoptosis ↔ G Cytostasis → death Accumulation of stalled replication forks enforces S-phase arrest and amplifies cytotoxicity.
5 DNA damage response signaling (ATR/Chk1/Chk2) Checkpoint activation ↔ R, G Damage signaling Replication stress activates ATR/Chk1/Chk2 and modulates cell-cycle checkpoints and repair responses.
6 NF-κB pro-survival signaling (resistance axis) NF-κB activation can reduce sensitivity ↔ R, G Resistance/modulation In some tumor models, NF-κB and other pro-survival axes mediate resistance to gemcitabine cytotoxicity; inhibition sensitizes cells.
7 Autophagy modulation (response to stress) Autophagy ↑ in some contexts (cytoprotective) ↔ G Adaptive stress response Gemcitabine can induce autophagy as a survival mechanism in some models; autophagy inhibition can sensitize cells in combination studies.
8 Reactive oxygen species (ROS) elevation (indirect) ROS ↑ (reported in some models) ↔ G Stress amplification Some preclinical studies report ROS increases secondary to replication stress; not a primary mechanism but modulates cell-death pathways.
9 Clinical resistance mechanisms (CDA, nucleoside transporters) CDA ↑; hENT1 ↓ correlates with resistance — G Resistance / exposure constraint Cytidine deaminase (CDA) inactivates gemcitabine; lower hENT1 transport reduces uptake — major clinical resistance factors.
10 Bioavailability / pharmacokinetics (IV dosing; systemic exposure) IV infusion achieves systemic levels ↔ — PK constraint Gemcitabine is given systemically (often IV) and achieves cytotoxic blood levels; rapid deamination by CDA and short half-life shape dosing.

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

  • P: 0–30 min (rapid biochemical activation / early metabolic engagement)
  • R: 30 min–3 hr (acute nucleotide pool effects / checkpoint signaling)
  • G: >3 hr (DNA damage response, cell death, 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⟱
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↓,

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 ⓘ

PDHB↓, 1,   PKM2↓, 1,  

Cell Death ⓘ

Apoptosis↑, 1,  

Transcription & Epigenetics ⓘ

tumCV↓, 1,  

Migration ⓘ

TumCI↓, 1,   TumCMig↓, 1,  

Drug Metabolism & Resistance ⓘ

eff↑, 1,  
Total Targets: 7

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

 

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