Capsaicin / PKM2 Cancer Research Results

CAP, Capsaicin: Click to Expand ⟱

Features:

Capsaicin is a chemical compound that gives chili peppers their spicy flavor and heat.

Biological activity, capsaicin has been reported to exhibit a range of effects, including:
Pain relief: 10-50 μM
Anti-inflammatory activity: 20-50 μM
Antioxidant activity: 10-100 μM
Anti-cancer activity: 50-100 μM
Cardiovascular health: 20-50 μM

Approximate μM concentrations of capsaicin, the active compound in chili peppers, that can be achieved with different amounts of chili peppers:
1 teaspoon of dried chili pepper flakes (5g):~10-50 μM of capsaicin
1 tablespoon of dried chili pepper flakes (15g): ~30-150 μM of capsaicin
1 cup of fresh chili peppers (100g): ~100-500 μM of capsaicin
1 teaspoon of chili pepper extract (5g): ~100-500 μM of capsaicin
1 tablespoon of chili pepper extract (15g): ~300-1500 μM of capsaicin

Approximate μM concentrations of capsaicin in various foods that contain capsaicin:
Jalapeño peppers: 1 pepper (20g): ~20-100 μM of capsaicin 2–8 mg/100g of fresh Jalapeño
Serrano peppers: 1 pepper (10g): ~10-50 μM of capsaicin 5–15 mg/100g
Cayenne peppers: 1 pepper (10g): ~50-200 μM of capsaicin
Habanero peppers: 1 pepper (20g): ~100-500 μM of capsaicin 15–30 mg/100g
Ghost peppers: 1 pepper (20g): ~200-1000 μM of capsaicin
Hot sauce: 1 teaspoon (5g): ~10-50 μM of capsaicin
Chili flakes: 1 teaspoon (5g): ~10-50 μM of capsaicin
Spicy sauces and marinades: 1 tablespoon (15g): ~10-50 μM of capsaicin

Cayenne Pepper Powder – Approximate capsaicin content: roughly 5–20 mg/g (15-30g human for 100uM?)

-IC50 in Cancer Cell Lines: Approximately 50–300 µM (consume 150mg of capsaican not possible?)
-IC50 in Normal Cell Lines: Generally higher—often 2–3 times greater

Pathways:
-disrupting mitochondrial membrane potential, leading to cytochrome c release and subsequent activation of caspases
-Activation of TRPV1: resulting in increased intracellular calcium levels
-capsaicin can lead to increased production of ROS within cancer cells
-Inhibition of NF-κB
-Inhibit PI3K/AKT/mTOR signaling
-STAT3 Inhibition
-Cell Cycle Arrest
-reduce the expression of vascular endothelial growth factor (VEGF)
-COX-2
-capsaicin is a natural ADAM10 activator and shows potential to attenuate amyloid pathology and protect against AD

Capsaicin — capsaicin is a pungent vanilloid alkaloid phytochemical from Capsicum peppers and the principal TRPV1 agonist responsible for chili heat. It is best classified as a natural product / small-molecule vanilloid with approved topical analgesic use but no established anticancer indication. Standard abbreviations include CAP and CAPS. In cancer literature it is a pleiotropic stressor whose dominant preclinical effects usually converge on Ca2+ influx, mitochondrial dysfunction, ROS generation, suppression of pro-survival signaling, and apoptosis, but its biology is context- and concentration-dependent, with occasional low-dose pro-migratory / pro-metastatic signaling reported.

Primary mechanisms (ranked):

TRPV-linked cation influx with intracellular Ca2+ dysregulation, variably via TRPV1 or other TRPV-family context such as TRPV6
Mitochondrial injury with loss of membrane potential, cytochrome c release, and intrinsic apoptotic execution
Mitochondrial and cellular ROS increase with redox stress exceeding tumor buffering capacity
Suppression of STAT3 and related survival transcription programs in multiple models
Suppression of NF-κB-centered inflammatory / survival signaling, with downstream anti-migratory and radiosensitizing implications in some settings
PI3K/Akt/mTOR attenuation and cell-cycle restraint in responsive models
Contextual induction of autophagy as a stress-adaptation program that may either accompany death or partially buffer it
Anti-migratory / anti-invasive effects in many models, but with an important low-concentration exception in some colorectal systems

Bioavailability / PK relevance: Capsaicin is lipophilic, rapidly absorbed, and rapidly metabolized, with substantial first-pass limitation after oral exposure. Human oral PK from a capsicum preparation containing 26.6 mg capsaicin produced a Cmax of about 2.47 ng/mL at ~47 minutes, while the FDA-approved 8% topical system produced transient systemic exposure usually below 5 ng/mL, with a highest detected plasma level of 4.6 ng/mL. Delivery is therefore a major translation constraint for anticancer use, and formulation-based approaches are often invoked to overcome short half-life, irritancy, and exposure limits.

In-vitro vs systemic exposure relevance: This is a major limitation. Many anticancer cell studies use roughly 10–300 µM, whereas reported human plasma exposures from oral or approved topical use are in the low ng/mL range, approximately ~0.008–0.015 µM, i.e., orders of magnitude lower than many cytotoxic in-vitro concentrations. Accordingly, direct systemic tumoricidal translation from standard dietary or approved topical exposure is weak unless local delivery, sustained-release systems, or substantially altered formulations are used.

Clinical evidence status: Anticancer evidence is predominantly preclinical, with in-vitro and some in-vivo support across several tumor types. There is no regulatory approval for cancer treatment. Human oncology use is currently much more credible as supportive care for neuropathic pain, especially chemotherapy-induced peripheral neuropathy, where topical high-concentration capsaicin patches are being studied and used off-label / investigationally, rather than as a direct antitumor therapy.

Mechanistic Table

Rank	Pathway / Axis	Cancer Cells	Normal Cells	TSF	Primary Effect	Notes / Interpretation
1	TRPV-linked Ca2+ influx	Ca2+ ↑; death signaling ↑	Sensory excitation ↑; irritancy ↑	P/R	Upstream trigger	Usually framed through TRPV1, but some tumor models show dependence on other TRPV-family context such as TRPV6; this is mechanistically central but not uniform across cancers.
2	Mitochondrial membrane potential	MMP ↓; cytochrome c release ↑	↔ / stress if exposed	R	Intrinsic apoptosis initiation	Mitochondrial dysfunction is one of the most reproducible downstream events and often links Ca2+ overload with apoptosis.
3	Mitochondrial ROS increase	ROS ↑; redox buffering overwhelmed	↔ / antioxidant response may compensate	P/R	Stress amplification	Frequently sits upstream of mitochondrial collapse, DNA damage signaling, and apoptosis; cancer selectivity is often attributed to weaker redox reserve.
4	Intrinsic apoptosis machinery	BAX/Bak ↑; Bcl-2/Bcl-xL ↓; caspase-3/9 ↑	↔ / lower sensitivity in some comparisons	R/G	Execution-phase cell death	Common endpoint across responsive models; often follows ROS and mitochondrial injury rather than acting as the primary initiating lesion.
5	STAT3 survival signaling	STAT3 ↓	↔	R/G	Reduced survival and proliferation	Well supported in multiple myeloma and other models, but not universal; note that a HepG2 context reported ROS-associated STAT3 activation coupled to autophagy.
6	NF-κB inflammatory survival axis	NF-κB ↓	Inflammatory tone ↓	R/G	Anti-survival; anti-migratory	Important for invasion restraint and likely part of observed radiosensitization in some models.
7	PI3K Akt mTOR axis	PI3K/Akt/mTOR ↓	↔	R/G	Growth suppression	Seen in several responsive systems, but this axis is also part of the cautionary low-dose pro-metastatic literature in colorectal cancer.
8	Cell-cycle control	G0/G1 or G1/S arrest ↑	↔	G	Proliferation blockade	Usually secondary to upstream stress and survival-pathway suppression rather than the earliest event.
9	Autophagy stress program	Autophagy ↑ (context-dependent)	↔	G	Adaptive buffering or co-lethal stress	In HepG2, autophagy appeared partially protective because inhibiting it enhanced capsaicin-induced apoptosis.
10	Migration invasion EMT phenotype	Migration ↓; invasion ↓; EMT ↓ (context-dependent)	↔	G	Anti-metastatic phenotype	Frequently reported at active doses, often linked to AMPK activation and NF-κB suppression.
11	Low-dose paradox flag	ROS ↑ with Akt/mTOR ↑ and STAT3 ↑ (model-dependent)	↔	G	Potential pro-metastatic signaling	Important caution: low-concentration capsaicin has been reported to enhance metastatic behavior in colorectal cancer models.
12	Radiosensitization or Chemosensitization	Sensitivity ↑ (context-dependent)	Unknown	G	Adjunct potential	Preclinical support exists, especially via NF-κB and stress-pathway modulation, but this remains non-clinically established for direct cancer treatment.
13	Clinical Translation Constraint	Required tumoricidal exposure often not reached systemically	Irritation and tolerability limit escalation	G	Translation bottleneck	Typical antitumor in-vitro concentrations greatly exceed known plasma exposure from standard oral intake or approved topical use; formulation, local delivery, and tumor heterogeneity are major constraints.

P: 0–30 min

R: 30 min–3 hr

G: >3 hr

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⟱

2347-

CAP,

Capsaicin ameliorates inflammation in a TRPV1-independent mechanism by inhibiting PKM2-LDHA-mediated Warburg effect in sepsis

in-vivo,

Nor,

in-vitro,

Nor,

RAW264.7

*PKM2↓, *LDHA↓, *Warburg↓, *COX2↓, *Sepsis↓, *Inflam↓, *ECAR↓, *OCR↑,

2394-

CAP,

Capsaicin acts as a novel NRF2 agonist to suppress ethanol induced gastric mucosa oxidative damage by directly disrupting the KEAP1-NRF2 interaction

in-vitro,

Nor,

GES-1

(0, 2, and 8 μM)

*mtDam↓, *NRF2↑, *HO-1↑, *Trx↑, *GSS↑, *NQO1↑, *Keap1↓, *ROS↓, *PKM2↓, *LDHA↓, *Inflam↓,

2349-

CAP,

The TRPV1-PKM2-SREBP1 axis maintains microglial lipid homeostasis in Alzheimer’s disease

in-vivo,

AD,

mouse brain

*TRPV1↑, *PKM2↓, *SREBP2↑, *memory↑,

2348-

CAP,

Recent advances in analysis of capsaicin and its effects on metabolic pathways by mass spectrometry

Analysis,

Nor,

Warburg↓, *PKM2↓, *COX2↓, *Inflam↓, *Sepsis↓, *AMPK↑, *PKA↑, *mitResp↑, *FAO↑, *FASN↓, *PGM1?, *ATP↑, *ROS↓,

Showing Research Papers: 1 to 4 of 4

* indicates research on normal cells as opposed to diseased cells
Total Research Paper Matches: 4

Pathway results for Effect on Cancer / Diseased Cells:

Core Metabolism/Glycolysis ⓘ

Warburg↓, 1,
Total Targets: 1

Pathway results for Effect on Normal Cells:

Infection & Microbiome ⓘ

Sepsis↓, 2,
Total Targets: 26

Scientific Paper Hit Count for: PKM2, Pyruvate Kinase, Muscle 2

4 Capsaicin

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

Capsaicin / PKM2 Cancer Research Results

Mechanistic Table

Pathway results for Effect on Cancer / Diseased Cells:

Core Metabolism/Glycolysis ⓘ

Pathway results for Effect on Normal Cells:

Redox & Oxidative Stress ⓘ

Mitochondria & Bioenergetics ⓘ

Core Metabolism/Glycolysis ⓘ

Cell Death ⓘ

Migration ⓘ

Immune & Inflammatory Signaling ⓘ

Functional Outcomes ⓘ

Infection & Microbiome ⓘ

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