Auranofin / NRF2 Cancer Research Results

AF, Auranofin: Click to Expand ⟱
Features:

Auranofin — an orally administered gold(I) coordination complex (gold–phosphine–thiolate “thiosugar” drug) originally approved as a disease-modifying antirheumatic drug (DMARD) for rheumatoid arthritis and widely studied for repurposing as a redox-targeted anticancer and anti-infective agent. It is a small-molecule metallodrug whose pharmacology is typically tracked via blood/plasma gold concentrations because intact auranofin is rapidly transformed and not reliably detected in blood. Standard abbreviation(s): AF (auranofin); primary target shorthand: TrxR/TxNRD (thioredoxin reductase).

Primary mechanisms (ranked):

  1. Thioredoxin reductase (TXNRD1/TXNRD2; TrxR) inhibition by gold(I) → thioredoxin system suppression and loss of redox-buffering capacity
  2. ROS and redox stress escalation (secondary to TrxR blockade; often NAC-reversible in models) → apoptosis and other regulated death programs
  3. Mitochondrial dysfunction (Δψm collapse, bioenergetic stress) coupled to redox imbalance
  4. Proteostasis stress (ER stress/UPR; proteasome involvement in selected contexts) → non-apoptotic death phenotypes (model-dependent)
  5. Ferroptosis contribution in subsets of models (lipid peroxidation–dependent; context-dependent)
  6. Radiosensitization / chemosensitization via impaired antioxidant recovery and enhanced oxidative injury (context-dependent)
  7. Stress-response transcription (e.g., NRF2 activation as an adaptive resistance program in some settings; protective in normal cells)

Bioavailability / PK relevance: Oral absorption is incomplete; clinical PK is commonly described as ~25% of the gold content absorbed. Gold is highly protein-bound and exhibits prolonged retention/long terminal half-life, so effective exposure depends strongly on dose and dosing duration. Because “gold levels” are the main measurable surrogate, cross-study comparisons should specify matrix (whole blood vs plasma) and timing (steady-state vs short course).

In-vitro vs systemic exposure relevance: Many oncology cell studies use ~0.5–5 µM AF. Human short-course data at 6 mg/day for 7 days report plasma gold on the order of ~0.1–0.3 µg/mL (roughly sub-µM to ~1–1.5 µM range when expressed as gold equivalents), meaning lower in-vitro ranges can overlap clinically observed exposure surrogates, while higher µM regimens may exceed typical oral exposures unless higher doses/longer courses or formulation changes are used.

Clinical evidence status: Approved for rheumatoid arthritis (historical DMARD use) but oncology use remains investigational. Multiple early-phase repurposing trials exist across hematologic and solid tumors; several completed studies have limited publicly posted outcomes, and there is no established standard-of-care anticancer indication.


Pathways:
1.Thioredoxin Reductase (TrxR) Inhibition.
- Most widely recognized for potently inhibiting TrxR.
2.Induction of Reactive Oxygen Species (ROS) and Oxidative Stress.
3.MMP depolarization, release of cytochrome c
4.Endoplasmic Reticulum (ER) Stress and Unfolded Protein Response (UPR)
5.Inhibition of Pro-survival Pathways (e.g., NF-κB Signaling)

-ic50 for cancer typically 1-3uM, normal cell 5-10uM or higher.
-Several studies animal testing antitumor efficacy have used doses in the region of 5–8 mg/kg via intraperitoneal injection or oral administration.

-Auranofin’s anticancer activity is often linked to its inhibition of thioredoxin reductase, leading to increased oxidative stress.

Mechanistic axes for Auranofin (Cancer vs Normal)

Rank Pathway / Axis Cancer Cells Normal Cells TSF Primary Effect Notes / Interpretation
1 TXNRD1 TXNRD2 Thioredoxin system ↓ (primary) ↓ (primary) P→R Collapse of thioredoxin redox buffering Core, proximal target of AF; downstream effects track with redox reserve and compensatory antioxidant capacity rather than tumor lineage alone.
2 ROS redox stress ↑ (often primary downstream) ↑ (dose-dependent) P→R Oxidative injury signaling and death pathway engagement Frequently reversible with thiol antioxidants (e.g., NAC) in models, supporting causality; magnitude depends on baseline redox fragility.
3 Mitochondria bioenergetics Δψm ↓, ATP stress ↑ (context-dependent) Δψm ↓ (dose-dependent) R Energetic crisis and intrinsic death susceptibility Often coupled to redox imbalance; can amplify apoptosis/regulated necrosis depending on cellular checkpoints.
4 Proteostasis ER stress UPR ↑ (model-dependent) ↔/↑ (high exposure only) R→G Protein-folding overload and non-apoptotic death phenotypes Some reports implicate proteasome participation and paraptosis-like outcomes; not universal across tumor types.
5 NRF2 antioxidant response ↑ (adaptive; resistance role) ↑ (cytoprotective) R→G Transcriptional compensation to redox stress NRF2 induction can blunt AF efficacy in tumors yet protect normal tissues; net effect is (context-dependent).
6 Ferroptosis lipid peroxidation ↑ (model-dependent) ↔/↑ (stress-prone contexts) R→G Regulated death component in subsets Most consistent when AF-driven redox stress converges on lipid ROS handling; requires model-specific validation.
7 Radiosensitization chemosensitization ↑ sensitivity (context-dependent) ↑ toxicity risk (context-dependent) R→G Impaired antioxidant recovery increases treatment injury Mechanistically coherent with TrxR blockade; best supported where oxidative damage markers and combination indices are shown.
8 Ca²⁺ stress coupling ↑/↔ (secondary) ↑/↔ (secondary) R Amplifies ER mitochondrial death signaling Usually downstream of redox + organelle perturbation; include when Ca²⁺-dependent apoptosis/ER stress is explicitly demonstrated.
9 Glycolysis ATP production ↓ (context-dependent) ↔/↓ (high exposure only) R Metabolic stress that can reduce proliferative fitness Reported in some models; may be secondary to mitochondrial/redox disruption rather than a primary binding target.
10 HIF-1α hypoxia programs ↔ (model-dependent) G Context marker rather than core axis Evaluate case-by-case; AF’s primary leverage is redox enzyme inhibition, with HIF effects emerging indirectly in some systems.
11 Clinical Translation Constraint Exposure, tolerability, and selectivity limit window Oral absorption is incomplete and gold is long-retained/protein-bound; many oncology studies rely on µM in-vitro dosing that may exceed typical oral exposure surrogates. Oncology trials exist but anticancer efficacy is not established as standard-of-care.

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⟱
5471- AF,    Anti-Tumoral Treatment with Thioredoxin Reductase 1 Inhibitor Auranofin Fosters Regulatory T Cell and B16F10 Expansion in Mice
- vitro+vivo, Melanoma, B16-F10
TrxR1↓, AntiTum↑, ROS↑, NRF2↑, TumCD↑,
5470- AF,    Exploring a Therapeutic Gold Mine: The Antifungal Potential of the Gold-Based Antirheumatic Drug Auranofin
- Review, Var, NA
TrxR↓, other↝, IL6↑, IL8↑, NK cell⇅, COX2↓, NOS2↓, NRF2↑, Prx↑, Half-Life↑, Dose↝, ROS↑, NF-kB↓,

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:


Redox & Oxidative Stress

NRF2↑, 2,   Prx↑, 1,   ROS↑, 2,   TrxR↓, 1,   TrxR1↓, 1,  

Cell Death

TumCD↑, 1,  

Transcription & Epigenetics

other↝, 1,  

Immune & Inflammatory Signaling

COX2↓, 1,   IL6↑, 1,   IL8↑, 1,   NF-kB↓, 1,   NK cell⇅, 1,  

Drug Metabolism & Resistance

Dose↝, 1,   Half-Life↑, 1,  

Clinical Biomarkers

IL6↑, 1,   NOS2↓, 1,  

Functional Outcomes

AntiTum↑, 1,  
Total Targets: 17

Pathway results for Effect on Normal Cells:


Total Targets: 0

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#:273  Target#:226  State#:%  Dir#:2
wNotes=0 sortOrder:rid,rpid

 

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