Caffeic acid / NRF2 Cancer Research Results

CA, Caffeic acid: Click to Expand ⟱
Features:
Caffeic acid is a polyphenol antioxidant found in coffee, fruits, vegetables, and herbs. It may have anti-inflammatory, anticancer, anti-aging, and other health benefits.
Caffeic acid (CA) is a dietary hydroxycinnamic acid found widely in plant foods and in coffee largely as chlorogenic acids (caffeoylquinic acids). CA is generally antioxidant / anti-inflammatory and is frequently reported to modulate Nrf2 and NF-κB signaling, with downstream effects on survival pathways (PI3K/AKT), MAPKs, cell cycle, and apoptosis in preclinical cancer models. A notable mechanistic nuance is a context-dependent pro-oxidant effect described in the presence of copper (Cu), where CA can drive oxidative DNA damage in vitro (often discussed as potentially relevant to tumors with higher copper levels).

-Caffeic acid phenethyl ester, the main representative component of propolis
-Black chokeberry 141.14 mg/100 g F
-Sunflower seed, meal 8.17 mg/100 g FW
-Common sage, dried 26.40 mg/100 g FW
-Ceylan cinnamon 24.20 mg/100 g FW
-Nutmeg 16.30 mg/100 g FW

-Dual capacity of CA to act as an antioxidant during carcinogenesis and as a pro-oxidant against cancer cells, promoting their apoptosis or sensitizing them to chemotherapeutic drugs.

Pathways:
-Caffeic acid is a potent antioxidant
-Caffeic acid may also exhibit pro-oxidant behavior. At higher concentrations( 50–100 µM ?) or/and in the presence of transition metal ions (such as copper or iron), caffeic acid can participate in Fenton-like reactions, potentially leading to increased ROS generation.
-Shown to inhibit NF-κB activation
-Inhibitory effects on MAPK/ERK Pathway
-PI3K/Akt Signaling Pathway
-Activation of the Nrf2/ARE pathway
-Cell cycle arrest at various checkpoints
-Angiogenesis Inhibition

Caffeic acid typically shows low oral bioavailability (sometimes only a few percent of the ingested dose is systemically available) and a short plasma half-life (around 1–2 hours in animal models).

Caffeic acid — Caffeic acid is a dietary hydroxycinnamic acid polyphenol present in coffee, fruits, vegetables, and many herbs, and is also generated from hydrolysis of chlorogenic acids. It is formally classified as a small-molecule plant phenolic acid with redox-active, anti-inflammatory, and signal-modulating properties. Standard abbreviations include CA for caffeic acid; it should be distinguished from CAPE (caffeic acid phenethyl ester), which is a different propolis-derived ester with overlapping but not identical pharmacology. In cancer research, CA is best viewed as a pleiotropic preclinical modulator of inflammatory signaling, stress adaptation, metabolism, apoptosis, invasion, and angiogenesis, with translation limited by rapid conjugation and generally low free-aglycone systemic exposure.

Primary mechanisms (ranked):

  1. Suppression of inflammatory/pro-survival transcription, especially IL-6/JAK/STAT3 and NF-κB signaling.
  2. Redox modulation, usually antioxidant/cytoprotective in normal cells but capable of context-dependent pro-oxidant activity in cancer models, particularly with transition metals or higher in-vitro exposure.
  3. Down-modulation of ERK and PI3K/AKT survival signaling with downstream effects on proliferation and apoptosis.
  4. Induction of mitochondrial apoptosis and cell-cycle arrest in susceptible tumor models.
  5. Anti-invasive and anti-angiogenic effects, including reduced MMP/EMT outputs and suppression of STAT3-HIF-1α-VEGF signaling.
  6. Metabolic reprogramming in some models, including AMPK-linked disruption of tumor energy homeostasis and glycolytic dependence.
  7. Clinical translation constraint: extensive phase-II metabolism means circulating exposure is dominated by conjugated metabolites rather than sustained free caffeic acid.

Bioavailability / PK relevance: CA is absorbable in humans, but after oral intake much of the circulating material appears rapidly as sulfate, glucuronide, and methylated metabolites rather than persistent free aglycone. Peak plasma timing is typically early, and delivery is constrained less by gut uptake than by fast metabolic conversion and short-lived free exposure.

In-vitro vs systemic exposure relevance: Many anticancer studies use tens of micromolar CA, and some mechanistic claims depend on 50–100 µM or higher conditions that are not reliably reproduced as sustained free systemic exposure after ordinary oral intake. Accordingly, anti-inflammatory/adjuvant interpretations translate better than claims requiring strong direct tumor-cidal free-drug concentrations; metal-assisted pro-oxidant effects are especially context-dependent.

Clinical evidence status: Primarily preclinical. The cancer evidence base consists mainly of cell and animal studies, with some adjunct/chemosensitization signals. Human oncology evidence remains very limited; at least one registered esophageal squamous cell carcinoma trial has been reported, but caffeic acid is not an established anticancer drug or standard adjunct.

Mechanistic matrix

Rank Pathway / Axis Cancer Cells Normal Cells TSF Primary Effect Notes / Interpretation
1 IL-6 / JAK / STAT3 signaling ↓ ↔ / ↓ inflammatory tone R, G Anti-survival transcription One of the cleaner current cancer axes for CA itself; suppression links to reduced proliferation, migration, and anti-apoptotic signaling.
2 NF-κB inflammatory transcription ↓ ↓ inflammatory stress R, G Anti-inflammatory / anti-survival Consistent across reviews and multiple models, but CA is generally a weaker and less canonical NF-κB inhibitor than CAPE.
3 ROS redox modulation ↔ / ↑ (context-dependent) ↓ oxidative injury P, R Redox reprogramming CA is usually antioxidant in normal tissues, yet can become pro-oxidant in tumor or copper-rich settings; direction is strongly model- and dose-dependent.
4 ERK and PI3K / AKT survival signaling ↓ ↔ R, G Growth and resistance suppression Frequently appears upstream of reduced clonogenicity, apoptosis sensitization, and lower chemoresistance in acidic or stressed tumor states.
5 Mitochondrial apoptosis Bax ↑, caspase-3 ↑, Bcl-2 ↓ ↔ / relative sparing G Cell death execution Usually a downstream endpoint rather than the first event; strongest in susceptible cell lines and higher in-vitro exposure.
6 Cell-cycle machinery cyclin D ↓, arrest ↑ ↔ G Cytostasis Phase of arrest varies by model; best treated as a secondary phenotype following signaling and redox changes.
7 MMP / EMT / invasion programs MMP2/9 ↓, EMT ↓, migration ↓ ↔ G Anti-invasive effect Supported in several tumor models, though part of the older invasion literature is stronger for caffeic-acid derivatives than for CA itself.
8 STAT3-HIF-1α-VEGF angiogenesis axis HIF-1α ↓, VEGF ↓ ↔ G Anti-angiogenic support Includes in-vivo support in renal carcinoma xenograft work; useful mechanistically, but still preclinical.
9 AMPK and tumor energy metabolism AMPK ↑, glycolytic dependence ↓ ↔ / context-dependent R, G Metabolic stress Relevant in selected cancers rather than universally. Better framed as model-dependent metabolic rewiring than as a universal glycolysis inhibitor.
10 NRF2 antioxidant response ↔ / ↑ (context-dependent) ↑ R, G Stress adaptation Important for normal-cell protection and toxicity mitigation. In tumors, NRF2 activation may be beneficial, neutral, or counterproductive depending on context, so it is not a uniformly favorable anticancer axis.
11 Clinical Translation Constraint Free CA exposure limited Conjugated metabolites predominate — PK limitation Human absorption occurs, but circulating chemistry is dominated by rapid conjugation. Many direct in-vitro tumoricidal concentrations likely exceed sustained free systemic levels achievable by routine oral dosing.

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

  • P: 0–30 min (rapid redox/metal interactions; early signaling shifts)
  • R: 30 min–3 hr (acute stress-response + transcription signaling changes)
  • G: >3 hr (gene-regulatory adaptation and phenotype outcomes)
NRF2, nuclear factor erythroid 2-related factor 2: Click to Expand ⟱
Source: TCGA
Type: Antiapoptotic
Nrf2 is responsible for regulating an extensive panel of antioxidant enzymes involved in the detoxification and elimination of oxidative stress. Thought of as "Master Regulator" of antioxidant response.
-One way to estimate Nrf2 induction is through the expression of NQO1.
NQO1, the most potent inducer:
SFN 0.2 μM,
quercetin (2.5 μM),
curcumin (2.7 μM),
Silymarin (3.6 μM),
tamoxifen (5.9 μM),
genistein (6.2 μM ),
beta-carotene (7.2μM),
lutein (17 μM),
resveratrol (21 μM),
indol-3-carbinol (50 μM),
chlorophyll (250 μM),
alpha-cryptoxanthin (1.8 mM),
and zeaxanthin (2.2 mM)

1. Raising Nrf2 enhances the cell's antioxidant defenses and ↓ROS. This strategy is used to decrease chemo-radio side effects.
2. Downregulating Nrf2 lowers antioxidant defenses and ↑ROS. In cancer cells this leads to DNA damage, and cell death.
3. However there are some cases where increasing Nrf2 paradoxically causes an increase in ROS (cancer cells). Such as cases of Mitochondial overload, signal crosstalk, reductive stress

-In some cases, Nrf2 is overexpressed in cancer cells, which can lead to the activation of genes involved in cell proliferation, angiogenesis, and metastasis. This can contribute to the development of resistance to chemotherapy and targeted therapies.
-Increased Nrf2 expression: Lung, Breast, Colorectal, Prostrate.
Decreased Nrf2 expression: Skine, Liver, Pancreatic.
-Nrf2 is a cytoprotective transcription factor which demonstrated both a negative effect as well as a positive effect on cancer
- "promotes Nrf2 translocation from the cytoplasm to the nucleus," means facilitates the movement of Nrf2 into the nucleus, thereby enhancing the cell's antioxidant and cytoprotective responses. -Major regulator of Nrf2 activity in cells is the cytosolic inhibitor Keap1.

Nrf2 Inhibitors and Activators
Nrf2 Inhibitors: Brusatol, Luteolin, Trigonelline, VitC, Retinoic acid, Chrysin
Nrf2 Activators: SFN, OPZ EGCG, Resveratrol, DATS, CUR, CDDO, Api
- potent Nrf2 inducers from plants include sulforaphane, curcumin, EGCG, resveratrol, caffeic acid phenethyl ester, wasabi, cafestol and kahweol (coffee), cinnamon, ginger, garlic, lycopene, rosemany

Nrf2 plays dual roles in that it can protect normal tissues against oxidative damage and can act as an oncogenic protein in tumor tissue.
– In healthy tissues, NRF2 activation helps protect cells from oxidative damage and maintains cellular homeostasis.
– In many cancers, constitutive activation of NRF2 (often through mutations in NRF2 itself or loss-of-function mutations in KEAP1) leads to an enhanced antioxidant capacity.
– This upregulation can promote tumor cell survival by enabling cancer cells to thrive under oxidative stress, resist chemotherapeutic agents, and sustain metabolic reprogramming.
– Elevated NRF2 levels have been implicated in promoting tumor growth, metastasis, and resistance to therapy in various malignancies.
– High or sustained NRF2 activity is frequently associated with aggressive tumor phenotypes, poorer prognosis, and decreased overall survival in several cancer types.
– While its activation is essential for protecting normal cells from oxidative stress, aberrant or sustained NRF2 activation in tumor cells can lead to enhanced survival, therapeutic resistance, and tumor progression.

NRF2 inhibitors: (to decrease antioxidant defenses and increase cell death from ROS).
-Brusatol: most cited natural inhibitors of Nrf2.
-Luteolin: luteolin can reduce Nrf2 activity in specific cancer models and may enhance cell sensitivity to chemotherapy. However, luteolin is also known as an antioxidant, and its influence on Nrf2 can sometimes be context dependent.
-Apigenin: certain studies to down‑regulate Nrf2 in cancer cells: Dose and context dependent .
-Oridonin:
-Wogonin: although its effects might be cell‑ and dose‑specific.
- Withaferin A

Scientific Papers found: Click to Expand⟱
7516- CA,    Caffeic Acid, a Polyphenolic Micronutrient Rescues Mice Brains against Aβ-Induced Neurodegeneration and Memory Impairment
- in-vivo, AD, NA
*neuroP↑, *antiOx↑, *memory↑, *Learn↑, *cognitive↑, *ROS↓, *lipid-P↓, *NRF2↑, *HO-1↑, *Aβ↓, *BACE/β-secretase↓,

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:


Total Targets: 0

Pathway results for Effect on Normal Cells:


NA, unassigned(tgid=0) ⓘ

Learn↑, 1,  

Redox & Oxidative Stress(tgid=1) ⓘ

antiOx↑, 1,   HO-1↑, 1,   lipid-P↓, 1,   NRF2↑, 1,   ROS↓, 1,  

Protein Aggregation(tgid=19) ⓘ

Aβ↓, 1,   BACE/β-secretase↓, 1,  

Functional Outcomes(tgid=23) ⓘ

cognitive↑, 1,   memory↑, 1,   neuroP↑, 1,  
Total Targets: 11

Scientific Paper Hit Count for: NRF2, nuclear factor erythroid 2-related factor 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#:51  Target#:226  State#:%  Dir#:%
  wNotes=0  sortOrder:rid,rpid

 

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