Auranofin / ER Stress 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
ER Stress, endoplasmic reticulum (ER) stress signaling pathway: Click to Expand ⟱
Source:
Type:
Protein expression of ATF, GRP78, and GADD153 which is a hall marker of ER stress.
The endoplasmic reticulum (ER) stress signaling pathway plays a crucial role in maintaining cellular homeostasis and responding to various stressors, including those encountered in cancer. When cells experience stress, such as the accumulation of misfolded proteins, they activate a series of signaling pathways collectively known as the unfolded protein response (UPR). The UPR aims to restore normal function by enhancing the protein-folding capacity of the ER, degrading misfolded proteins, and, if the stress is unresolved, triggering apoptosis.
The activation of ER stress pathways can contribute to resistance against chemotherapy and targeted therapies. Cancer cells may utilize the UPR to survive treatment-induced stress, making it challenging to achieve effective therapeutic outcomes.

-ER stress-associated proteins include: phosphorylation of PERK, eIF2α, ATF4, CHOP and cleaved-caspase 12
Scientific Papers found: Click to Expand⟱
5461- AF,    Dual inhibition of thioredoxin reductase and proteasome is required for auranofin-induced paraptosis in breast cancer cells
- in-vitro, BC, MDA-MB-231 - in-vitro, Nor, MCF10
Paraptosis↑, ER Stress↑, TrxR↓, selectivity↑, toxicity↝, ROS↑, mt-TrxR1↓, mt-TrxR2↓,

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:


Redox & Oxidative Stress ⓘ

ROS↑, 1,   TrxR↓, 1,   mt-TrxR1↓, 1,   mt-TrxR2↓, 1,  

Cell Death ⓘ

Paraptosis↑, 1,  

Protein Folding & ER Stress ⓘ

ER Stress↑, 1,  

Drug Metabolism & Resistance ⓘ

selectivity↑, 1,  

Functional Outcomes ⓘ

toxicity↝, 1,  
Total Targets: 8

Pathway results for Effect on Normal Cells:


Total Targets: 0

Scientific Paper Hit Count for: ER Stress, endoplasmic reticulum (ER) stress signaling pathway
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#:103  State#:%  Dir#:2
  wNotes=0  sortOrder:rid,rpid

 

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