brusatol / HO-1 Cancer Research Results

BRU, brusatol: Click to Expand ⟱
Features:
Brusatol is a quassinoid (highly oxygenated triterpenoid derivative) isolated from Brucea javanica. It is best known in oncology research as a potent functional inhibitor of the Nrf2 pathway, which places it at the center of redox regulation, chemoresistance, and mitochondrial stress in cancer cells.


Brusatol — brusatol is a naturally occurring quassinoid, a highly oxygenated degraded triterpenoid isolated mainly from Brucea javanica. It is best characterized as a preclinical small-molecule anticancer sensitizer that suppresses stress-response and survival signaling, with the strongest historical association being transient depletion of NRF2-dependent cytoprotective signaling. Its formal classification is a plant-derived natural product and experimental anticancer chemosensitizer. Standard abbreviations include BRU and BT. Mechanistically, current evidence no longer supports treating brusatol as a clean or selective NRF2 inhibitor; rather, NRF2 suppression appears to be one important downstream consequence of broader translational and short-lived protein depletion, with additional context-dependent effects on STAT3, AKT/mTOR, EGFR-linked signaling, EMT/metastasis programs, and ferroptosis susceptibility.

Primary mechanisms (ranked):

  1. Global translational suppression with preferential depletion of short-lived stress-survival proteins, including NRF2
  2. Functional suppression of the NRF2 antioxidant program with downregulation of HO-1, NQO1, GCLC and related redox-defense outputs
  3. ROS amplification and redox-vulnerability induction, especially in combination settings
  4. Inhibition of survival signaling pathways including STAT3 and, in some models, PI3K/AKT/mTOR
  5. Promotion of mitochondrial apoptosis with caspase activation and Bcl-2-family shift
  6. Anti-invasive and anti-metastatic activity via EMT suppression and reduced MMP/ROCK-associated migratory signaling
  7. Ferroptosis sensitization or induction in selected models through NRF2-system xCT-GSH axis disruption
  8. Chemosensitization and radiosensitization through collapse of adaptive cytoprotective resistance programs

Bioavailability / PK relevance: Native brusatol has meaningful delivery constraints and limited development maturity. Published PK work is mainly preclinical, including intravenous mouse and rat studies, tissue-distribution studies, metabolite identification, and formulation work designed to improve oral exposure. Nanoparticle and self-microemulsifying systems have been explored because practical systemic delivery and therapeutic index remain limiting issues.

In-vitro vs systemic exposure relevance: Many cell studies use submicromolar to low-micromolar concentrations, which may be pharmacologically active but are not yet anchored to a validated human exposure range because there is no established clinical dosing framework. Some mechanistic claims likely reflect concentration- and model-dependent pleiotropy. Combination efficacy appears more translationally relevant than assuming selective single-target inhibition at fixed in-vitro concentrations.

Clinical evidence status: Preclinical only. Evidence includes extensive in-vitro work and multiple animal studies showing tumor-growth inhibition and sensitization to chemotherapy or targeted therapy, but no established human oncology efficacy and no identified registered interventional cancer trial establishing clinical use of purified brusatol as an anticancer drug.

Mechanistic relevance of brusatol in cancer

Rank Pathway / Axis Cancer Cells Normal Cells TSF Primary Effect Notes / Interpretation
1 Protein translation suppression ↓ short-lived survival proteins ↓ protective proteins P-R Upstream cytotoxic driver Best current high-level interpretation. Explains why NRF2 falls rapidly but also why brusatol affects multiple unrelated pathways; reduces confidence in strict target selectivity.
2 NRF2 antioxidant program ↓ NRF2, ↓ HO-1, ↓ NQO1, ↓ GCLC ↓ NRF2 defense possible P-R Redox-defense collapse Historically central mechanism and still highly relevant functionally, especially for chemosensitization, but likely not exclusive or fully specific.
3 Oxidative stress increase ↑ ROS ↑ injury risk (context-dependent) R-G Redox crisis and death sensitization Often emerges after antioxidant-program suppression; especially important in combination with cisplatin, taxanes, trastuzumab, lapatinib, or ferroptosis-linked settings.
4 Mitochondrial apoptosis ↑ Bad or Bax signaling, ↓ Bcl-2, ↑ caspase-9, ↑ caspase-3 ↔ to ↑ toxicity risk R-G Execution of tumor cell death Common endpoint across models. Frequently linked to ROS accumulation and survival-pathway shutdown.
5 STAT3 and JAK kinase signaling ↓ JAK1/2, ↓ Src, ↓ STAT3, ↓ nuclear STAT3 ↔ R-G Reduced growth, survival, EMT, metastasis Supported strongly in HNSCC and HCC systems; likely important in subsets where STAT3 is dominant.
6 PI3K AKT mTOR axis ↓ PI3K, ↓ p-AKT, ↓ mTOR ↔ R-G Proliferation and survival suppression Observed in several tumor models; may be partly direct in some contexts and partly secondary to broader stress signaling collapse in others.
7 EGFR related signaling ↓ EGFR-TK activity, ↓ HER2-AKT-ERK signaling ↔ R-G Growth inhibition and targeted-therapy sensitization Evidence includes cell-free EGFR-TK inhibition and combination activity in HER2-positive models. Relevance is plausible but not yet as established as the redox-survival axes.
8 EMT and metastasis program ↓ EMT, ↓ migration, ↓ invasion, ↓ MMP2, ↓ MMP9, ↓ ROCK1 ↔ G Anti-metastatic effect Seen in colorectal, HCC, NSCLC, ESCC and other models. Often downstream of STAT3, AKT, or redox disruption.
9 Ferroptosis susceptibility ↑ ferroptosis sensitivity, ↓ GSH defense ↔ to ↑ oxidative vulnerability R-G Non-apoptotic death facilitation Growing 2025-2026 literature suggests this is mechanistically relevant in some cancers, but still appears context-dependent rather than universal.
10 Chemosensitization and radiosensitization ↑ chemo response, ↑ radio response ↔ to ↓ tissue tolerance G Resistance reversal One of the most reproducible translational themes. Benefit likely comes from disabling adaptive antioxidant and pro-survival buffering rather than from a single receptor-like target.
11 Clinical Translation Constraint Bioavailability limits, pleiotropy, toxicity interaction risk Potential collateral stress sensitization G Restrains development No established clinical oncology deployment. Preclinical PK is limited, formulation optimization is still active, and recent work suggests brusatol can worsen cisplatin nephrotoxicity by altering cisplatin pharmacokinetics.

P: 0–30 min

R: 30 min–3 hr

G: >3 hr
HO-1, HMOX1: Click to Expand ⟱
Source:
Type:
(Also known as Hsp32 and HMOX1)
HO-1 is the common abbreviation for the protein (heme oxygenase‑1) produced by the HMOX1 gene.
HO-1 is an enzyme that plays a crucial role in various cellular processes, including the breakdown of heme, a toxic molecule. Research has shown that HO-1 is involved in the development and progression of cancer.
-widely regarded as having antioxidant and cytoprotective effects
-The overall activity of HO‑1 helps to reduce the pro‐oxidant load (by degrading free heme, a pro‑oxidant) and to generate molecules (like bilirubin) that can protect cells from oxidative damage

Studies have found that HO-1 is overexpressed in various types of cancer, including lung, breast, colon, and prostate cancer. The overexpression of HO-1 in cancer cells can contribute to their survival and proliferation by:
  Reducing oxidative stress and inflammation
  Promoting angiogenesis (the formation of new blood vessels)
  Inhibiting apoptosis (programmed cell death)
  Enhancing cell migration and invasion
When HO-1 is at a normal level, it mainly exerts an antioxidant effect, and when it is excessively elevated, it causes an accumulation of iron ions.

A proper cellular level of HMOX1 plays an antioxidative function to protect cells from ROS toxicity. However, its overexpression has pro-oxidant effects to induce ferroptosis of cells, which is dependent on intracellular iron accumulation and increased ROS content upon excessive activation of HMOX1.

-Curcumin   Activates the Nrf2 pathway leading to HO‑1 induction; known for its anti‑inflammatory and antioxidant effects.
-Resveratrol  Induces HO‑1 via activation of SIRT1/Nrf2 signaling; exhibits antioxidant and cardioprotective properties.
-Quercetin   Activates Nrf2 and related antioxidant pathways; contributes to anti‑oxidative and anti‑inflammatory responses.
-EGCG     Promotes HO‑1 expression through activation of the Nrf2/ARE pathway; also exhibits anti‑inflammatory and anticancer properties.
-Sulforaphane One of the most potent natural HO‑1 inducers; triggers Nrf2 nuclear translocation and upregulates a battery of phase II detoxifying enzymes.
-Luteolin    Induces HO‑1 via Nrf2 activation; may also exert anti‑inflammatory and neuroprotective effects in various cell models.
-Apigenin   Has been reported to induce HO‑1 expression partly via the MAPK and Nrf2 pathways; also known for anti‑inflammatory and anticancer activities.
Scientific Papers found: Click to Expand⟱
5690- BJ,  BRU,    Brusatol: A potential sensitizing agent for cancer therapy from Brucea javanica
- Review, Var, NA
NRF2↓, TumCG↓, ChemoSen↑, ROS↑, NF-kB↓, Akt↓, mTOR↓, TumCCA↑, Apoptosis↑, PARP↑, Casp↑, P53↓, Bcl-2↓, PI3K↓, JAK2↓, EMT↓, p27↑, ROCK1↓, MMP2↓, MMP9↓, NRF2↓, AntiTum↑, HO-1↓, NQO1↓, VEGF↓, MRP1↓, RadioS↑, PhotoS↑, toxicity↝,

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 ⓘ

HO-1↓, 1,   NQO1↓, 1,   NRF2↓, 2,   ROS↑, 1,  

Cell Death ⓘ

Akt↓, 1,   Apoptosis↑, 1,   Bcl-2↓, 1,   Casp↑, 1,   p27↑, 1,  

Transcription & Epigenetics ⓘ

PhotoS↑, 1,  

DNA Damage & Repair ⓘ

P53↓, 1,   PARP↑, 1,  

Cell Cycle & Senescence ⓘ

TumCCA↑, 1,  

Proliferation, Differentiation & Cell State ⓘ

EMT↓, 1,   mTOR↓, 1,   PI3K↓, 1,   TumCG↓, 1,  

Migration ⓘ

MMP2↓, 1,   MMP9↓, 1,   ROCK1↓, 1,  

Angiogenesis & Vasculature ⓘ

VEGF↓, 1,  

Immune & Inflammatory Signaling ⓘ

JAK2↓, 1,   NF-kB↓, 1,  

Drug Metabolism & Resistance ⓘ

ChemoSen↑, 1,   MRP1↓, 1,   RadioS↑, 1,  

Functional Outcomes ⓘ

AntiTum↑, 1,   toxicity↝, 1,  
Total Targets: 28

Pathway results for Effect on Normal Cells:


Total Targets: 0

Scientific Paper Hit Count for: HO-1, HMOX1
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#:385  Target#:597  State#:%  Dir#:1
  wNotes=0  sortOrder:rid,rpid

 

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