Caffeic Acid Phenethyl Ester (CAPE) / NRF2 Cancer Research Results

CAPE, Caffeic Acid Phenethyl Ester (CAPE): Click to Expand ⟱
Features:

Caffeic Acid Phenethyl Ester (CAPE) — CAPE is a propolis-derived phenolic ester and bioactive honeybee-hive constituent with pleiotropic anti-inflammatory and antineoplastic signaling effects. It is best classified as a natural polyphenolic small molecule and experimental adjunct candidate rather than an approved anticancer drug. Standard abbreviations include CAPE; common chemical naming includes caffeic acid phenethyl ester and phenethyl caffeate. CAPE is most strongly associated with poplar-type propolis chemistry, but it is also available as an ingredient in some dietary-supplement products. Current oncology relevance remains preclinical to early translational, with growing interest in chemosensitization and radiosensitization but no established cancer indication.

Primary mechanisms (ranked):

  1. NF-κB pathway inhibition with downstream suppression of pro-inflammatory and pro-survival transcription
  2. PI3K/Akt and p70S6K network suppression with reduced proliferation and survival signaling
  3. Wnt/β-catenin/TCF inhibition with reduced cyclin D1 and c-MYC signaling
  4. Anti-invasive / anti-metastatic modulation via reduced MMP expression and related motility programs
  5. Mitochondrial and metabolic stress reprogramming, including membrane depolarization and a shift toward glycolysis in some tumor models
  6. Chemo/radiosensitization in selected models, including autophagy inhibition and context-dependent enhancement of cytotoxic therapy
  7. Secondary redox and cytoprotective modulation, including ROS buffering or oxidative stress induction depending on model and exposure
  8. Secondary eicosanoid/inflammatory enzyme effects, including COX-2 and lipoxygenase-related signaling suppression

Bioavailability / PK relevance: Oral translation is constrained by poor aqueous solubility, limited absorption, esterase-sensitive disposition, and substantial hydrolysis to caffeic acid in vivo. Rat PK work supports measurable exposure after oral dosing, but CAPE analogues with improved permeability outperform parent CAPE. Formulation strategies are therefore mechanistically relevant for systemic use.

In-vitro vs systemic exposure relevance: Many direct anticancer studies use roughly 10–60 μM exposure, with some effects emerging near or above this range; those concentrations may exceed or stress the upper edge of practical systemic exposure with simple oral delivery. Tumor-directed claims should therefore be weighted more heavily when supported by in vivo xenograft, radiosensitization, or formulation-enabled data rather than cell culture alone.

Clinical evidence status: Predominantly preclinical with in vitro, xenograft, and ex vivo support; small translational signals exist for radiosensitization/radioprotection concepts, but there is no established oncology trial program or approved cancer use for CAPE itself.

CAPE — Cancer vs Normal Cell Pathway Map

Rank Pathway / Axis Cancer Cells Normal Cells TSF Primary Effect Notes / Interpretation
1 NF-κB inflammatory transcription NF-κB ↓; inflammatory/pro-survival gene programs ↓ Inflammatory stress ↓ P/R Anti-inflammatory and anti-survival signaling suppression Most canonical CAPE axis; supported by classic mechanistic work and newer radiosensitization studies. Central for cytokine, survival, and stress-response attenuation.
2 PI3K/Akt / p70S6K / c-MYC Akt ↓; p70S6K ↓; c-MYC ↓; proliferation ↓ ↔ / protective (context-dependent) R/G Cytostatic and pro-apoptotic pressure Strong relevance in prostate and NSCLC models; appears therapeutically leveraged in combination settings.
3 Wnt / β-catenin / TCF β-catenin ↓; nuclear β-catenin ↓; cyclin D1 ↓; c-MYC ↓ R/G Growth arrest and apoptosis support Well supported in colon cancer models; helps explain antiproliferative and differentiation-related effects.
4 MMP invasion / metastasis axis MMP-2 ↓; MMP-9 ↓; MT1-MMP ↓; invasion ↓ ECM injury/inflammation ↓ (context-dependent) R/G Anti-invasive and anti-metastatic effect Useful translational axis because it links inflammatory signaling to motility and matrix remodeling.
5 Mitochondria / metabolic reprogramming Mitochondrial membrane potential ↓; respiration shift toward glycolysis Potential radioprotective anti-inflammatory support in tissue slices P/R Stress amplification and therapeutic-window modulation Recent lung data suggest CAPE can destabilize tumor bioenergetics while dampening inflammatory injury signals in normal tissue contexts.
6 Autophagy / chemosensitization Autophagy ↓; oxaliplatin sensitivity ↑ R/G Adjunct sensitization to therapy Now a meaningful secondary axis; 2024 colon-cancer work supports autophagy inhibition as one mechanism of drug sensitization.
7 Radiosensitization RadioS ↑ (adenocarcinoma-selective in some models) Radiation-associated inflammatory injury ↓ (context-dependent) R/G Potential therapeutic-window expansion Important emerging translational niche rather than a universal CAPE effect; appears histology- and context-dependent.
8 ROS / NRF2 redox modulation (secondary) ROS ↔ / ↑ / ↓ (context-dependent); NRF2 ↔ / ↑ (secondary) ROS injury ↓; cytoprotective antioxidant tone ↑ (context-dependent) P/R/G Redox buffering or oxidative stress depending on setting CAPE is not best treated as a simple antioxidant. In tumors it may contribute to stress and death signaling, while in normal tissue it may support anti-inflammatory/radioprotective responses.
9 COX-2 / lipoxygenase inflammatory eicosanoids COX-2-related signaling ↓; LOX-related signaling ↓ Inflammatory eicosanoid tone ↓ P/R Inflammation and microenvironment restraint Mechanistically plausible and historically supported, but generally more secondary than NF-κB/Akt/β-catenin in oncology framing.
10 Clinical Translation Constraint Bioavailability ↓; exposure consistency ↓ Systemic delivery limitations ↑ Formulation-limited translation Poor solubility, hydrolysis, and variable absorption limit confidence that common oral dosing reproduces stronger in vitro anticancer concentrations.

TSF legend: P: 0–30 min; R: 30 min–3 hr; G: >3 hr



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⟱
5768- CAPE,    Neuroprotective Potential of Caffeic Acid Phenethyl Ester (CAPE) in CNS Disorders: Mechanistic and Therapeutic Insights
- Review, AD, NA - Review, Park, NA - Review, Stroke, NA
*antiOx↑, *Inflam↑, *AntiCan↑, *NRF2↑, *GSK‐3β↑, *Akt↑, *PI3K↑, *ROS↓, *SOD↑, *GSH↑, *MDA↓, *tau↓, *neuroP↑, *memory↑, *AChE↓, *other↝, *lipid-P↓,
5766- CAPE,    A Nano-Liposomal Formulation of Caffeic Acid Phenethyl Ester Modulates Nrf2 and NF-κβ Signaling and Alleviates Experimentally Induced Acute Pancreatitis in a Rat Model
- in-vivo, Nor, NA
*MDA↓, *NF-kB↓, *p65↓, *TNF-α↓, *cl‑Casp3↓, *GSR↑, *GSH↑, *NRF2↑, *HO-1↑, *Bax:Bcl2↓, *antiOx↑, *Inflam↓,

Showing Research Papers: 1 to 2 of 2

* indicates research on normal cells as opposed to diseased cells
Total Research Paper Matches: 2

Pathway results for Effect on Cancer / Diseased Cells:


Total Targets: 0

Pathway results for Effect on Normal Cells:


Redox & Oxidative Stress

antiOx↑, 2,   GSH↑, 2,   GSR↑, 1,   HO-1↑, 1,   lipid-P↓, 1,   MDA↓, 2,   NRF2↑, 2,   ROS↓, 1,   SOD↑, 1,  

Cell Death

Akt↑, 1,   Bax:Bcl2↓, 1,   cl‑Casp3↓, 1,  

Transcription & Epigenetics

other↝, 1,  

Proliferation, Differentiation & Cell State

GSK‐3β↑, 1,   PI3K↑, 1,  

Immune & Inflammatory Signaling

Inflam↓, 1,   Inflam↑, 1,   NF-kB↓, 1,   p65↓, 1,   TNF-α↓, 1,  

Synaptic & Neurotransmission

AChE↓, 1,   tau↓, 1,  

Functional Outcomes

AntiCan↑, 1,   memory↑, 1,   neuroP↑, 1,  
Total Targets: 25

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#:395  Target#:226  State#:%  Dir#:%
wNotes=0 sortOrder:rid,rpid

 

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