CUSP9 / P-gp/ABCB1 Cancer Research Results

CUSP9, CUSP9: Click to Expand ⟱
Features:
CUSP9 coordinated undermining of survival paths with nine repurposed drugs
-includes aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, sertraline, ritonavir

CUSP9 — CUSP9 is a coordinated multi-drug repurposing regimen for glioblastoma built around the concept of Coordinated Undermining of Survival Paths. It is a polypharmacologic adjunct oncology protocol rather than a single molecular entity, formally classified as a multi-agent drug-repurposing regimen used with low-dose metronomic temozolomide in the clinically tested CUSP9v3 version. Standard abbreviations include CUSP9, CUSP9*, and CUSP9v3. The regimen originated from the International Initiative for Accelerated Improvement of Glioblastoma Care and subsequent Ulm University clinical development.

Primary mechanisms (ranked):

  1. Multi-pathway blockade of glioblastoma survival, invasion, inflammation, redox adaptation, efflux, and compensatory resistance networks.
  2. Redox stress amplification through thioredoxin reductase inhibition, ALDH inhibition, ROS generation, and impaired detoxification capacity.
  3. Temozolomide augmentation through resistance-pathway suppression, metronomic alkylator pressure, and reduced adaptive escape rather than a single direct chemosensitizing target.
  4. Invasion and microenvironment suppression through angiotensin, MMP, COX-2, microglial, cytokine, and inflammatory axes.
  5. Drug transport and exposure modulation through P-gp, BCRP, CYP, and BBB-relevant pharmacology, with both therapeutic and toxicity implications.
  6. Apoptosis and mitochondrial stress, particularly in CUSP9v3 combinations and in vitro TTFields plus CUSP9v3 experiments.

Bioavailability / PK relevance: CUSP9 is orally administered and highly PK-constrained because it combines multiple approved drugs with different half-lives, CNS penetration, protein binding, hepatic metabolism, and CYP or transporter effects. CUSP9v3 specifically requires careful dose escalation and monitoring because ritonavir, itraconazole, aprepitant, celecoxib, sertraline, and other components create clinically meaningful interaction potential. BBB exposure is component-specific and may not scale linearly with plasma exposure.

In-vitro vs systemic exposure relevance: CUSP9 is concentration-driven, but the clinically relevant question is not the exposure of one drug alone; it is whether simultaneous low-to-moderate exposure across multiple repurposed agents can suppress glioblastoma escape pathways. Some in-vitro work used clinically oriented fixed concentrations, but sensitivity is model-dependent, and lower-order subsets may match or exceed the full nine-drug cocktail in some patient-derived cultures. Translation should therefore treat in-vitro efficacy as supportive, not definitive.

Clinical evidence status: Preclinical rationale is extensive and includes multiple in-vitro glioblastoma and glioma stem-like cell studies. Human evidence is small but real: compassionate-use experience and a phase Ib/IIa recurrent glioblastoma trial support feasibility and tolerability under careful monitoring. Efficacy remains unproven because randomized outcome data are not yet available. CUSP9/CUSP9v3 is not an approved oncology regimen; its components are approved for other indications.

CUSP9 cancer mechanism table

Rank Pathway / Axis Cancer Cells Normal Cells TSF Primary Effect Notes / Interpretation
1 Multi-pathway survival network blockade Parallel GBM survival routes ↓; compensatory escape ↓; heterogeneity buffering ↓ Broad off-target burden possible; toxicity depends on cumulative dose and interactions G Resistance-network suppression Core identity of CUSP9; strongest conceptual rationale is simultaneous weak-to-moderate pressure across many GBM survival axes rather than a dominant single target.
2 Redox detoxification and thioredoxin axis Thioredoxin reductase ↓; ALDH ↓; ROS ↑; apoptotic susceptibility ↑ Redox reserve may be stressed; hepatic and hematologic monitoring relevant R/G Pro-oxidant tumor stress Auranofin and disulfiram are central contributors. This is one of the clearest mechanistic pressure points in CUSP9v3.
3 Temozolomide resistance and chemosensitization Adaptive survival pathways ↓; TMZ escape capacity ↓; alkylator pressure maintained Myelosuppression and cumulative tolerability remain limiting G Adjunct chemosensitization CUSP9v3 was clinically tested with continuous low-dose metronomic temozolomide. Some in-vitro data found limited added benefit from TMZ under specific conditions, so this row is clinically important but mechanistically model-dependent.
4 Invasion and extracellular matrix remodeling MMP-2 ↓; MMP-9 ↓; migration ↓; invasion ↓ Normal inflammatory and wound-remodeling processes may also be affected G Anti-invasive activity Captopril and minocycline in CUSP9v3 are most relevant; original and variant CUSP9 compositions differ, so component-specific interpretation is required.
5 Inflammatory COX and prostaglandin signaling COX-2 ↓; PGE2-linked proliferation and inflammatory support ↓ GI, renal, cardiovascular, and blood pressure risks are clinically relevant G Inflammatory support suppression Celecoxib contributes anti-inflammatory and possible carbonic anhydrase-linked effects, but clinical leverage depends on tolerability and patient risk profile.
6 NK-1 substance P signaling NK-1 signaling ↓; proliferation and pro-survival signaling ↓ Generally tolerable, but CYP interaction context matters G Growth signal suppression Aprepitant is included for NK-1 receptor inhibition and supportive antiemetic pharmacology; its oncology role remains adjunctive and not independently validated as a GBM therapy.
7 Drug efflux and BBB exposure P-gp/BCRP-linked efflux ↓ or altered; intracellular drug exposure may ↑ Systemic drug exposure and interaction risk may ↑ R/G Exposure modulation Itraconazole, ritonavir, and sertraline can alter transporter or CYP-linked exposure. This can be therapeutically useful but is also a major safety constraint.
8 PI3K AKT mTOR and TCTP signaling AKT/mTOR survival tone ↓; TCTP-linked survival signaling ↓ Context-dependent effects on metabolism, mood, and systemic signaling G Growth and survival suppression Sertraline and ritonavir are relevant contributors. This is a secondary but mechanistically meaningful survival-axis target.
9 Hedgehog autophagy and sterol-linked signaling Hedgehog/autophagy programs ↓; adaptive survival ↓ Hepatic toxicity and CYP3A4 interactions are important G Adaptive pathway suppression Itraconazole is a key component, but this axis is limited by drug interaction and hepatic monitoring requirements.
10 Mitochondrial apoptosis and oxidative phosphorylation MOMP ↓; caspase-3 cleavage ↑; Bcl-2/Mcl-1 ↓; OXPHOS ↓ Potential mitochondrial stress is context-dependent R/G Apoptosis promotion Especially supported by recent TTFields plus CUSP9v3 in-vitro work, where combined treatment enhanced apoptosis and reduced respiratory chain activity.
11 Glioma stem-like phenotype and tumor sphere formation Sphere formation ↓; stem-like viability ↓; migration ↓ Normal neural progenitor relevance uncertain G Stem-like compartment suppression Reported in preclinical glioblastoma stem-like models, with heterogeneous response across cultures and possible subtype dependence.
12 Clinical Translation Constraint Potential benefit depends on simultaneous pathway pressure, tumor subtype, and achievable exposure Dose limitation, hepatic enzymes, GI effects, neurologic symptoms, CYP interactions, BBB variability, and adherence burden are major constraints G Feasibility and safety limitation Human evidence supports careful monitored administration, not routine efficacy. The regimen is complex and should be treated as investigational.

TSF legend: P: 0–30 min; R: 30 min–3 hr; G: >3 hr
P-gp/ABCB1, permeability-glycoprotein: Click to Expand ⟱
Source:
Type:
P-glycoprotein (P-gp), also known as multidrug resistance protein 1 (MDR1), is a membrane protein that plays a crucial role in the transport of various substances across cellular membranes. It is part of the ATP-binding cassette (ABC) transporter family.
P-glycoprotein is often overexpressed in a variety of cancers, including breast cancer, lung cancer, leukemia, and ovarian cancer.

- The overexpression of P-glycoprotein (P-gp), is widely considered as an important reason for the MDR (multidrug resistance).

ABCB1 - ATP-Binding Cassette Subfamily B Member 1 / P-Glycoprotein

Abbreviation: ABCB1, P-gp, P-glycoprotein, MDR1

Type: ATP-dependent membrane efflux transporter / multidrug resistance protein

Function: ABCB1 encodes P-glycoprotein, an ATP-binding cassette transporter that exports a broad range of drugs, xenobiotics, lipids, and other substrates across cellular membranes. It is highly expressed in barrier tissues including the intestine, liver, kidney, placenta, and blood-brain barrier, where it limits tissue accumulation of potentially harmful compounds.

Cancer: ↑ Frequently overexpressed or functionally activated in drug-resistant tumors. Increased ABCB1 lowers intracellular concentrations of many anticancer agents by actively transporting them out of cancer cells, producing multidrug resistance and reducing chemotherapy effectiveness.

Alzheimer's Disease: ↓ Reduced ABCB1/P-glycoprotein expression or transport activity at the blood-brain barrier is associated with impaired amyloid-β clearance from the brain. Lower P-gp function correlates with increased cerebral Aβ accumulation and may contribute to Alzheimer's disease progression.
Scientific Papers found: Click to Expand⟱
6237- CUSP9,    CUSP9* treatment protocol for recurrent glioblastoma: aprepitant, artesunate, auranofin, captopril, celecoxib, disulfiram, itraconazole, ritonavir, sertraline augmenting continuous low dose temozolomide
- NA, GBM, NA
PI3K↓, Akt↓, ROS↑, NF-kB↓, TNF-α↓, TLR2↓, other↓, TrxR↓, STAT3↓, MMPs↓, COX1↓, COX2/PTGS2↓, CA↓, ALDH↓, P-gp/ABCB1↓, HH↓, 5LO↓, mTOR↓, CycD3↓, Proteasome↓, other↓, MMP2↓, MMP9↓, ALDH↓, Copper↓,
6238- CUSP9,    A phase Ib/IIa trial of 9 repurposed drugs combined with temozolomide for the treatment of recurrent glioblastoma: CUSP9v3
- Trial, GBM, NA
toxicity↓, TrxR↓, ROS↓, TumCI↓, TumCMig↓, TumCA↓, MMP2↓, MMP9↓, COX2/PTGS2↓, ALDH↓, TumAuto↑, P-gp/ABCB1↓, eff↑,

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(tgid=1) ⓘ

Copper↓, 1,   ROS↓, 1,   ROS↑, 1,   TrxR↓, 2,  

Cell Death(tgid=5) ⓘ

Akt↓, 1,   Proteasome↓, 1,  

Transcription & Epigenetics(tgid=7) ⓘ

other↓, 2,  

Autophagy & Lysosomes(tgid=9) ⓘ

TumAuto↑, 1,  

Cell Cycle & Senescence(tgid=11) ⓘ

CycD3↓, 1,  

Proliferation, Differentiation & Cell State(tgid=12) ⓘ

ALDH↓, 3,   HH↓, 1,   mTOR↓, 1,   PI3K↓, 1,   STAT3↓, 1,  

Migration(tgid=13) ⓘ

5LO↓, 1,   CA↓, 1,   MMP2↓, 2,   MMP9↓, 2,   MMPs↓, 1,   TumCA↓, 1,   TumCI↓, 1,   TumCMig↓, 1,  

Barriers & Transport(tgid=15) ⓘ

P-gp/ABCB1↓, 2,  

Immune & Inflammatory Signaling(tgid=16) ⓘ

COX1↓, 1,   COX2/PTGS2↓, 2,   NF-kB↓, 1,   TLR2↓, 1,   TNF-α↓, 1,  

Drug Metabolism & Resistance(tgid=21) ⓘ

eff↑, 1,  

Functional Outcomes(tgid=23) ⓘ

toxicity↓, 1,  
Total Targets: 30

Pathway results for Effect on Normal Cells:


Total Targets: 0

Scientific Paper Hit Count for: P-gp/ABCB1, permeability-glycoprotein
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#:296  Target#:232  State#:%  Dir#:%
  wNotes=0  sortOrder:rid,rpid

 

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