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Phosphoinositide 3-kinase (PI3K) is one of the most frequently dysregulated signaling nodes in human cancer, controlling cell growth, proliferation, survival, and metabolism through the PI3K/AKT/mTOR pathway. While small-molecule PI3K inhibitors have advanced our understanding of this pathway, their clinical utility is constrained by dose-limiting toxicity, feedback reactivation of signaling, and the inability to eliminate the scaffolding functions of PI3K proteins. Proteolysis-targeting chimera (PROTAC) technology offers a fundamentally different strategy: rather than merely blocking kinase activity, PI3K-targeting PROTACs induce complete degradation of the PI3K protein via the ubiquitin-proteasome system (UPS), eliminating both catalytic and non-catalytic functions.
BOC Sciences provides integrated PROTAC targeting PI3K development services, covering PI3K ligand discovery, E3 ligase ligand selection, linker design, custom PROTAC synthesis, degradation assessment, ternary complex characterization, isoform selectivity profiling, and cellular functional validation. Our interdisciplinary platform supports pharmaceutical and biotechnology teams seeking to develop potent, selective, and developable PI3K degraders for oncology, metabolic disease, and PIK3CA-related overgrowth spectrum (PROS) research.
Why is PI3K a Suitable Target for PROTAC Development?
PI3Ks are a family of lipid kinases that phosphorylate the 3-hydroxyl group of phosphatidylinositol and its derivatives, playing central roles in cell growth, proliferation, survival, metabolism, and vesicular trafficking. Among them, Class I PI3Ks are the most extensively studied and are directly implicated in human cancer. These are heterodimeric lipid kinases composed of a p110 catalytic subunit (p110α, p110β, p110δ, or p110γ) and a regulatory subunit (p85, p101, or p84). The PIK3CA gene, encoding p110α, is one of the most frequently mutated oncogenes across human cancers, with hotspot mutations in breast, colorectal, endometrial, head and neck, and lung cancers. Beyond their kinase activity, PI3K proteins exert critical scaffolding functions that stabilize signaling complexes and coordinate downstream effector recruitment, functions that conventional ATP-competitive inhibitors cannot abolish.
Several factors make PI3K an exceptionally well-suited target for PROTAC-mediated degradation:
Kinase-dependent and kinase-independent functions: PI3K p110 isoforms possess scaffolding roles independent of their catalytic activity, including stabilization of the p85 regulatory subunit and facilitation of RAS-driven signaling. PROTAC-mediated degradation eliminates both functions simultaneously, an advantage unattainable by occupancy-based inhibitors.
Overcoming inhibitor resistance: Acquired resistance to PI3K inhibitors often arises from feedback activation of upstream receptor tyrosine kinases (RTKs), pathway reactivation through alternative PI3K isoforms, or kinase-domain mutations that reduce drug binding. Degrading the entire PI3K protein circumvents these resistance mechanisms.
Catalytic mechanism at substoichiometric concentrations: PROTACs act through an event-driven, catalytic mechanism, enabling sustained PI3K degradation at low drug concentrations. This contrasts with the sustained high target occupancy required by conventional inhibitors, which can exacerbate on-target toxicity in insulin-sensitive tissues.
Services
BOC Sciences' Comprehensive PI3K PROTAC Development Services
PI3K Ligand Discovery and Optimization
The selection and optimization of a PI3K-targeting warhead is the cornerstone of any PI3K PROTAC program. BOC Sciences supports PI3K ligand discovery across all isoforms using both structure-based and ligand-based approaches, ensuring high binding affinity, appropriate exit-vector geometry, and compatibility with linker conjugation.
Pan-PI3K and isoform-selective warhead screening: evaluation of known PI3K inhibitor scaffolds including 4-methylquinazoline, thienopyrimidine, and triazine derivatives against p110α, p110β, p110δ, and p110γ to identify starting points for PROTAC design
Structure-activity relationship (SAR) analysis: systematic assessment of PI3K-binding affinity (IC50/Kd), isoform selectivity, and cellular target engagement using binding affinity measurement platforms
PIK3CA mutant-specific ligand design: development of warheads targeting common oncogenic mutants including H1047R, E545K, and E542K with differentiated binding profiles
Ligand derivatization for PROTAC compatibility: chemical modification of validated PI3K ligands to introduce functional handles (amine, carboxyl, azide, alkyne) for linker conjugation while preserving target engagement
E3 Ligase Ligand Selection and Linker Design for PI3K Degraders
The choice of E3 ligase ligand and linker architecture critically influences degradation potency, isoform selectivity, ternary complex cooperativity, and drug-like properties of PI3K PROTACs. We provide integrated E3 ligase ligand selection and linker design and optimization services tailored to the unique structural features of PI3K proteins.
CRBN-based PROTAC development: design of PI3K degraders utilizing pomalidomide, lenalidomide, or next-generation cereblon (CRBN) ligands with optimized linker attachment points, supporting CRBN-based PROTAC development
VHL-based PROTAC development: engineering of PI3K PROTACs recruiting von Hippel-Lindau (VHL) E3 ligase, with careful optimization of VHL ligand stereochemistry and linker geometry, building on our VHL-based PROTAC development expertise
Alternative E3 ligase recruitment: exploration of IAP ligand design and MDM2 ligand design strategies for PI3K degradation, expanding the E3 ligase toolbox beyond CRBN and VHL
Linker attachment site analysis: evaluation of linker binding site selection and design on both the PI3K warhead and the E3 ligase ligand to maximize ternary complex formation and minimize steric clashes
In silico linker modeling: application of molecular dynamics simulation and 3D-QSAR to predict linker conformational preferences and guide rational design
Custom Synthesis of PI3K-Targeting PROTAC Molecules
BOC Sciences provides custom PROTAC synthesis services for PI3K-targeting degraders, from milligram-scale exploratory compounds to multi-gram quantities for advanced profiling. Our synthesis platform handles the complexity of bifunctional PROTAC molecules, including challenging linker-warhead conjugations and multi-step convergent syntheses.
Convergent and modular synthesis strategies: parallel preparation of PI3K ligand-linker and E3 ligand-linker intermediates followed by final assembly using amide coupling, click chemistry, or other bioorthogonal conjugation methods
PI3K PROTAC library synthesis: generation of focused PROTAC libraries varying PI3K warheads, E3 ligase ligands, linker types, linker lengths, and attachment vectors to enable systematic SAR exploration
Negative control synthesis: preparation of PROTAC diastereomer designs and inactive E3 ligase ligand controls to validate degradation mechanism specificity
Analytical characterization: full characterization of all PI3K PROTAC compounds by NMR, HPLC, and high-resolution mass spectrometry (HRMS) to confirm identity, purity, and structural integrity
Scale-up capability:PROTAC scale-up production from lead optimization quantities to larger batches supporting extensive in vitro and in vivo profiling
PI3K Degradation Assessment and Ternary Complex Characterization
Demonstrating that a PI3K PROTAC induces genuine ubiquitin-proteasome-dependent degradation—rather than nonspecific protein loss—requires a rigorous, multi-readout evaluation strategy. We offer comprehensive PROTAC in vitro evaluation to quantify PI3K degradation potency, kinetics, and mechanism.
Quantitative degradation analysis: determination of DC50 (concentration for 50% degradation) and Dmax (maximal degradation) values for each PI3K isoform using quantitative Western blotting and capillary-based immunoassay platforms across relevant cell lines
Degradation kinetics: time-course experiments (2 h to 48 h) measuring the rate and duration of p110α, p110β, p110δ, p110γ, and p85 protein loss following PROTAC treatment
Ternary complex characterization:PROTAC ternary complex assay using TR-FRET, bead-based luminescence proximity assays, or SPR to measure PI3K–PROTAC–E3 ligase complex formation, cooperativity (α), and the hook effect concentration range
Ubiquitination confirmation:protein ubiquitination analysis to verify UPS-dependent degradation, including rescue experiments with proteasome inhibitors (MG132, bortezomib) and neddylation inhibitors (MLN4924)
Mechanism-of-action validation: competition experiments with excess PI3K ligand or E3 ligase ligand to confirm that degradation requires both target engagement and E3 ligase recruitment
Isoform Selectivity Profiling and Off-Target Evaluation
Achieving degradation selectivity among the four class I PI3K isoforms is a central challenge in PI3K PROTAC development, given the high sequence homology of their ATP-binding pockets. BOC Sciences provides integrated isoform selectivity profiling and PROTAC off-target evaluation to characterize the degradation selectivity landscape.
Isoform-selective degradation profiling: parallel quantification of p110α, p110β, p110δ, and p110γ degradation in isogenic cell panels to establish isoform degradation selectivity ratios
PIK3CA mutant vs. wild-type selectivity: differential degradation assessment in cell lines harboring H1047R, E545K, E542K, or other hotspot mutations compared with wild-type PI3Kα models
Kinome-wide selectivity: evaluation of degradation specificity across the broader kinome using quantitative proteomics to confirm that observed biological effects are driven by PI3K degradation rather than off-target protein depletion
p85 co-degradation analysis: assessment of whether p110 degradation leads to concomitant loss of the p85 regulatory subunit, a unique consequence of PROTAC-mediated degradation that eliminates PI3K scaffolding functions
Non-target organelle and protein effects: screening for unintended degradation of structurally or functionally related lipid kinases, including PI4K and PIP5K family members
Cellular Pathway Analysis and Functional Validation of PI3K Degraders
Beyond measuring protein degradation, understanding the functional consequences of PI3K ablation on downstream signaling and cellular phenotype is essential for prioritizing PROTAC candidates. BOC Sciences offers comprehensive cellular pathway analysis and functional validation services.
PI3K/AKT/mTOR pathway suppression: quantitative analysis of p-AKT (Ser473, Thr308), p-S6 (Ser235/236), p-PRAS40, and p-GSK3β levels as pharmacodynamic markers of PI3K pathway inhibition following PROTAC treatment
Cell proliferation and viability: assessment of anti-proliferative effects across PI3K-dependent cancer cell lines (e.g., T47D, MCF7, HGC-27, DOHH2) using 2D and 3D culture models
Apoptosis and cell cycle analysis: measurement of caspase-3/7 activation, PARP cleavage, Annexin V staining, and cell cycle distribution to characterize the cellular response to PI3K degradation
Insulin signaling impact assessment: evaluation of PI3K degradation effects on insulin-stimulated AKT phosphorylation in metabolic-relevant cell models (hepatocytes, myotubes) to understand potential on-target effects in insulin-responsive tissues
Accelerate Your PI3K Degrader Program with BOC Sciences
From PI3K ligand optimization and E3 ligase selection through custom PROTAC synthesis, degradation profiling, isoform selectivity analysis, and in vivo evaluation, BOC Sciences offers end-to-end support for PI3K-targeting PROTAC development. Our integrated chemistry and biology platform is designed to reduce design–test cycles and generate decision-ready data for your PI3K degradation research.
PI3K Isoform-Specific PROTAC Development Capabilities
PI3K isoforms differ in activating inputs, regulatory subunits, tissue distribution, structural determinants, and biological dependencies. We therefore design each program around an isoform-specific target product profile rather than applying one generic degrader architecture to the entire PI3K family.
PI3Kα (PIK3CA)-Targeting PROTAC Development
PI3Kα programs commonly focus on activating PIK3CA variants such as H1047R, E545K, and E542K or on amplified PI3Kα signaling in solid-tumor models. We support mutant-aware warhead design, wild-type counter-screening, PIK3CA genotype selection, receptor-feedback analysis, and comparison of helical-domain versus kinase-domain mutant contexts. Degradation studies can be configured to determine whether mutant PI3Kα removal provides deeper or more durable pathway suppression than occupancy-based inhibition.
PI3Kβ (PIK3CB)-Targeting PROTAC Development
PI3Kβ can become an important signaling dependency in PTEN-deficient or receptor-adapted cellular systems. Our PI3Kβ degrader programs evaluate warhead selectivity against PI3Kα, define appropriate PTEN-null and PTEN-restored controls, examine GPCR- and receptor tyrosine kinase-driven signaling, and measure whether p110β removal affects both catalytic output and scaffold-associated functions. Isoform compensation is monitored during prolonged degradation experiments.
PI3Kδ (PIK3CD)-Targeting PROTAC Development
PI3Kδ is enriched in leukocytes and participates in antigen-receptor, cytokine, chemokine, and survival signaling. We develop PI3Kδ degraders for B-cell, T-cell, and other immune-cell research models, with emphasis on PI3Kγ counter-selectivity, cell-lineage-specific E3 ligase expression, pathway-stimulation conditions, and functional readouts such as AKT activation, cytokine response, migration, or survival. Primary-cell-compatible assay windows can be incorporated when appropriate for the research program.
PI3Kγ (PIK3CG)-Targeting PROTAC Development
PI3Kγ integrates G protein-coupled receptor signals and has context-dependent kinase and non-catalytic functions in myeloid and hematopoietic systems. Our PI3Kγ programs address p110γ complex composition, p101 or p84 regulatory context, PI3Kδ cross-reactivity, lineage-specific degradation, and downstream AKT signaling. The platform supports research into whether complete PI3Kγ removal produces phenotypes not reproduced by kinase-domain occupancy alone.
Have You Encountered Following Challenges in PI3K PROTAC Development?
Difficulty achieving degradation selectivity among highly homologous p110 isoforms despite using isoform-selective warheads
PI3K PROTAC molecules with strong target binding but weak or undetectable degradation activity
PI3K PROTAC Development Challenges and Our Integrated Solutions
PI3K PROTAC programs encounter multifaceted challenges that span chemistry, biology, and data interpretation. Our integrated solutions address each challenge through coordinated molecular design, rigorous mechanistic evaluation, and iterative optimization.
Balancing Degradation Potency, Linker Architecture, and Physicochemical Properties
The bifunctional nature of PI3K PROTACs creates inherent tension between degradation potency and drug-like properties. Long, flexible linkers may promote ternary complex formation but often increase molecular weight beyond 900 Da, reduce cellular permeability, and elevate cLogP. Our solution is to generate systematic linker matrices—varying length (4 to 22 atoms), composition (PEG, alkyl, rigid aromatic, heterocyclic, peptidomimetic), and attachment vectors—and evaluate each candidate for degradation potency, PROTAC cellular permeability, solubility and stability, and ternary complex cooperativity. This multi-parameter approach identifies linker designs that achieve an acceptable balance between degradation efficiency and developability, avoiding the common pitfall of optimizing for DC50 alone.
Distinguishing Target Degradation from Nonspecific Cytotoxicity
PI3K PROTACs, particularly those incorporating hydrophobic E3 ligase ligands and extended linkers, may exhibit nonspecific cytotoxicity unrelated to target degradation. We implement a systematic mechanism-validation cascade: (1) proteasome-dependence confirmed by MG132 or bortezomib rescue; (2) neddylation-dependence confirmed by MLN4924 co-treatment; (3) competition with excess PI3K warhead or E3 ligase ligand; (4) comparison with an inactive diastereomer negative control; and (5) correlation analysis between degradation Dmax and anti-proliferative IC50 across a panel of PI3K-dependent and PI3K-independent cell lines. This multi-layered approach reliably separates PI3K-specific degradation activity from off-target cytotoxicity.
Addressing the Hook Effect and Optimizing the Therapeutic Window
The hook effect—where excessive PROTAC concentrations saturate binary complexes (PI3K–PROTAC and PROTAC–E3 ligase) at the expense of productive ternary complexes—can narrow the effective concentration range of PI3K degraders. Our approach is to characterize the hook effect early through ternary complex assays (TR-FRET or AlphaLISA) and degradation concentration–response curves spanning at least 4 log units. We then apply rational design strategies to mitigate the hook effect: optimizing binding cooperativity through linker geometry, tuning binary binding affinities, and exploring bivalent or trivalent PROTAC architectures. For each lead series, we define the degradation window—the concentration range between DC50 and the hook-effect onset—as a key optimization parameter.
Overcoming Poor Cellular Permeability of Bifunctional PI3K Degraders
PI3K PROTACs frequently violate Lipinski's Rule of Five due to their high molecular weight (typically 800–1,200 Da), extensive hydrogen-bond donors/acceptors, and large polar surface area. Our solution integrates permeability-aware design from the outset: (1) computational prediction of passive permeability using in-house models calibrated against PROTAC-specific datasets; (2) incorporation of intramolecular hydrogen bonds or N-methylation strategies to reduce exposed polarity; (3) evaluation of linker rigidity to minimize solvent-exposed rotatable bonds; and (4) experimental permeability measurement using Caco-2 or PAMPA assays in parallel with degradation assessment. This concurrent optimization ensures that promising degradation activity is not nullified by poor intracellular exposure.
Workflow
End-to-End Workflow for PI3K-Targeting PROTAC Development
01
Target and Model Definition
Define the PI3K isoform(s) of interest, relevant mutations (e.g., PIK3CA H1047R, E545K), cellular context, desired degradation selectivity profile, and key biological endpoints with the client. Establish PI3K-dependent and PI3K-independent cell line panels for subsequent profiling.
02
Warhead and Exit-Vector Design
Screen or design PI3K-targeting warheads with appropriate affinity, selectivity, and solvent-exposed conjugation positions. Map exit vectors through co-crystal structure analysis and protein structure modeling to identify linker attachment points compatible with ternary complex geometry.
03
Recruiter-Linker Matrix Construction
Build a design matrix combining selected E3 ligase ligands (CRBN, VHL, IAP, MDM2) with linkers of varying length, composition, and rigidity. Prioritize linker designs informed by ternary complex modeling and developability considerations.
04
Compound Synthesis and Analytical Characterization
Synthesize PI3K PROTAC molecules and corresponding negative controls using convergent or modular synthetic routes. Characterize all compounds by NMR, HPLC, and HRMS to confirm identity and purity.
05
Degradation Screening and Mechanism Confirmation
Screen compounds for PI3K degradation across relevant cell lines at multiple concentrations and time points. Confirm ubiquitin-proteasome dependence through inhibitor rescue, competition, and negative control experiments. Perform PROTAC ternary complex assay characterization.
06
Lead Optimization and Candidate Prioritization
Iterate on warhead structure, E3 ligase ligand choice, linker architecture, and physicochemical properties based on degradation potency (DC50, Dmax), isoform selectivity, ternary complex cooperativity, cellular permeability, metabolic stability, and functional pathway suppression data.
PI3K-targeting PROTACs hold significant promise in oncology research, where PI3K pathway hyperactivation is among the most common oncogenic events. Key application areas include:
The central role of PI3Kα in insulin signaling creates both challenges and opportunities for metabolic disease research. PI3K-targeting PROTAC applications in this area include:
Investigation of tissue-selective PI3K degradation strategies that spare insulin-sensitive tissues
Differentiation of PI3K kinase-dependent and scaffolding functions in hepatic glucose production and lipid metabolism
Exploration of isoform-specific degradation (e.g., PI3Kα vs. PI3Kβ) in adipose tissue biology and insulin sensitivity
Use of PI3K degraders as tool compounds to dissect the metabolic vs. mitogenic arms of PI3K signaling
PIK3CA-Related Overgrowth Spectrum Therapeutic Development
PIK3CA-Related Overgrowth Spectrum (PROS) encompasses a group of disorders caused by somatic activating PIK3CA mutations leading to asymmetric tissue overgrowth. PI3K-targeting PROTACs may offer a unique research approach for these conditions:
Design of PROTACs preferentially degrading mutant p110α over wild-type protein in mosaic tissues
Exploration of whether catalytic degradation provides more durable pathway suppression than kinase inhibition in PROS-relevant cell models
Evaluation of PI3Kα PROTAC effects on AKT/mTOR signaling in fibroblast and vascular cell models relevant to PROS pathology
Investigation of degradation-based strategies that address both kinase activity and scaffolding-driven growth signals
Drug Resistance and Precision Targeting
PI3K-targeting PROTACs represent a powerful research tool for addressing drug resistance and enabling precision degradation strategies:
Overcoming acquired resistance to ATP-competitive PI3K inhibitors arising from kinase-domain mutations or feedback RTK activation
Targeting PI3K scaffolding functions that persist during inhibitor treatment and contribute to residual signaling
Development of mutant-selective PROTACs that preferentially degrade oncogenic PI3K variants while sparing wild-type protein in normal tissues
Advantages of PI3K-Targeting PROTACs over Conventional Inhibitors
Event-Driven Catalytic Degradation at Low Concentrations
Unlike occupancy-driven inhibitors, PI3K PROTACs use an event-driven mechanism in which one molecule can trigger degradation of multiple PI3K proteins. This enables sustained pathway suppression at substoichiometric concentrations and may reduce the exposure associated with on-target effects such as hyperglycemia and insulin resistance.
Potential to Overcome Multiple PI3K Inhibitor Resistance Mechanisms
PI3K inhibitor resistance may involve kinase mutations, receptor tyrosine kinase feedback, alternative isoform signaling, or PTEN loss. By removing the entire PI3K protein, PROTACs can eliminate both catalytic and scaffolding functions, helping address residual signaling and adaptive resistance that may persist during kinase inhibition.
Enhanced PI3K Isoform and Mutant Selectivity
Degradation selectivity may exceed binding selectivity because ternary complex formation depends on E3 ligase orientation, protein-surface geometry, and lysine accessibility. These differences can support selective degradation of specific PI3K isoforms or mutants even when the warhead has broader binding activity.
Potential to Reduce Toxicity and Expand the Therapeutic Window
Catalytic degradation and improved isoform selectivity may enable effective pathway suppression at lower concentrations. Selective removal of oncogenic PI3K variants could reduce exposure in non-target tissues and potentially widen the therapeutic window compared with continuously occupied inhibitors.
Case Study
Client Success Stories: PI3K-Targeting PROTAC Development
Project Background
A pharmaceutical discovery team had identified a 4-methylquinazoline pan-PI3K inhibitor with single-digit nanomolar IC50 values against all four Class I isoforms. They aimed to convert it into a PI3Kα-selective PROTAC that preferentially degraded H1047R mutant p110α over wild-type protein. Their initial CRBN-based designs degraded multiple isoforms, prompting them to seek a more selective strategy.
Our Support
Co-crystal analysis of the warhead bound to p110α identified two solvent-exposed exit vectors near the solvent front and hinge-binding region. We designed 28 PROTACs combining these vectors with CRBN or VHL ligands and PEG, alkyl, or semi-rigid propargyl-PEG linkers.
Screening in T47D cells carrying heterozygous PIK3CA H1047R showed that a solvent-front, VHL-recruiting PROTAC with an 8-unit PEG linker preferentially degraded p110α with a DC50 of 0.12 μM and Dmax of 87%, while p110β and p110δ degradation remained below 15% at 1 μM. Shortening the linker to six PEG units and adding a propargyl spacer improved the DC50 to 0.048 μM and maintained more than 30-fold isoform selectivity.
In an isogenic MCF10A panel, the lead showed approximately threefold preferential degradation of H1047R mutant p110α over wild-type protein. Surface plasmon resonance analysis indicated positive cooperativity for the mutant ternary complex (α = 4.2), compared with near-neutral cooperativity for wild-type p110α (α = 1.3). The client received a selective lead series, structure–degradation relationships, and a mechanistic explanation for mutant preference.
Client Testimonial
BOC Sciences transformed our pan-PI3K inhibitor into a PI3Kα-selective degrader with mutant preference. Their co-crystal-guided design and ternary complex analysis provided both optimized molecules and a clear mechanistic rationale.
Project Background
A biotechnology company had developed a CRBN-based PI3Kδ PROTAC using a duvelisib-derived warhead. Although the series showed strong p110δ degradation in Raji cell lysate with a DC50 of 0.035 μM, activity in intact SU-DHL-4 and DOHH2 cells remained weak, with Dmax below 30% at 1 μM. Poor cellular permeability was suspected despite confirmed target engagement.
Our Support
PAMPA analysis confirmed low permeability, with a Papp of 0.8 × 10−6 cm/s. The lead also had a molecular weight of 1,047 Da and a topological polar surface area of 218 Å2. Nuclear magnetic resonance analysis showed extensive solvent exposure of the PEG linker.
We designed 19 analogs incorporating a shorter semi-rigid piperazine-triazole linker, an intramolecular hydrogen bond to shield polarity, and N-methylation of a solvent-exposed amide. These changes reduced polar surface area and linker flexibility while preserving CRBN binding.
The optimized analog improved PAMPA permeability to 4.6 × 10−6 cm/s. In intact SU-DHL-4 cells, it achieved a DC50 of 0.062 μM and Dmax of 91% at 0.3 μM, together with more than 70% suppression of p-AKT Ser473 and more than 80% inhibition of B-cell receptor-stimulated proliferation at 0.1 μM. Mouse liver microsomal half-life also increased from 12 to 48 minutes. The client received a redesigned PI3Kδ PROTAC series and transferable linker optimization principles.
Client Testimonial
BOC Sciences identified the permeability limitation and developed a practical linker redesign strategy that restored cellular degradation without compromising target engagement. The resulting design framework was also applicable to our other PROTAC programs.
Why Us
Why Choose BOC Sciences for PI3K-Targeting PROTAC Development?
Specialized Expertise Across PI3K Isoforms and Mutant Variants
We design programs around PI3Kα, PI3Kβ, PI3Kδ, or PI3Kγ biology and incorporate PIK3CA mutation status, PTEN background, regulatory partners, cell lineage, and pathway stimulus into assay selection.
Integrated End-to-End PROTAC Development Platform
Our platform coordinates target assessment, design, synthesis, biophysical testing, degradation assays, pathway analysis, and lead optimization within one project framework.
Customized PI3K Ligand, E3 Ligase, and Linker Design
Focused design matrices are tailored to the selected PI3K ligand and cellular context rather than generated through indiscriminate linker enumeration. Each analog is connected to a testable structural hypothesis.
Coordinated Chemistry and Biological Evaluation Capabilities
Chemists and assay scientists review data together, allowing synthetic changes to respond directly to target engagement, permeability, degradation, selectivity, and pathway findings.
Comprehensive Degradation, Selectivity, and Mechanistic Analysis
We assess more than endpoint protein reduction. Ternary complex formation, E3 dependence, proteasome dependence, ubiquitination, isoform selectivity, off-target effects, downstream signaling, and functional rescue are incorporated as needed.
Flexible Project Models and Dedicated Scientific Support
Clients may request a single module, such as warhead optimization or degradation profiling, or an end-to-end program. Experimental plans, decision criteria, and next-cycle recommendations are communicated clearly throughout the project.
Which PI3K isoform should a PROTAC program target?
Isoform selection should be guided by target biology, genetic background, cell type, and the desired functional readouts. PI3Kα is commonly prioritized in PIK3CA-mutant models, whereas PI3Kβ may be relevant to PTEN-deficient or receptor-adapted systems. PI3Kδ and PI3Kγ are frequently investigated in immune, hematopoietic, and myeloid signaling models. BOC Sciences integrates isoform expression, mutation status, regulatory partners, E3 ligase availability, and control models to define an appropriate degradation strategy.
Can PI3K PROTACs distinguish mutant and wild-type proteins?
PI3K PROTACs may achieve mutant-selective degradation, but selectivity cannot be predicted from warhead affinity alone. Degradation also depends on protein-surface topology, accessible lysine residues, E3 ligase orientation, linker conformation, and ternary complex cooperativity. Mutant and wild-type proteins should therefore be compared in matched or isogenic cellular models. Target engagement, protein loss, degradation kinetics, and downstream PI3K–AKT pathway responses should all be evaluated before mutant selectivity is assigned.
How is genuine PI3K degradation experimentally confirmed?
Genuine degradation requires more than observing reduced PI3K protein abundance. BOC Sciences can combine concentration- and time-dependent degradation measurements with rescue experiments using proteasome or neddylation inhibitors, competition with excess PI3K or E3 ligase ligands, inactive stereoisomer controls, ubiquitination analysis, and ternary complex characterization. These experiments help demonstrate that protein loss depends on target engagement, E3 ligase recruitment, ubiquitination, and the ubiquitin–proteasome system rather than nonspecific toxicity or assay interference.
Why do PI3K PROTACs show poor cellular permeability?
PI3K PROTACs contain a target-binding ligand, a linker, and an E3 ligase recruiter, which often produce high molecular weight, large exposed polar surface area, multiple hydrogen-bonding groups, and substantial conformational flexibility. Long polyethylene glycol linkers may further increase solvent-exposed polarity. Permeability can be improved through shorter or semi-rigid linkers, heterocyclic spacers, amide N-methylation, and intramolecular hydrogen-bond design, followed by PAMPA, Caco-2, and intracellular target-engagement testing.
How are linker and E3 ligase choices optimized?
Linkers and E3 ligase recruiters should be optimized as an integrated design matrix rather than selected independently. BOC Sciences systematically varies CRBN, VHL, or alternative recruiter modules together with linker length, rigidity, polarity, attachment position, and chemical composition. Compounds are then ranked using ternary complex formation, DC50, Dmax, degradation kinetics, hook-effect behavior, PI3K isoform selectivity, cellular permeability, and pathway suppression. This iterative process connects each structural change with a measurable degradation outcome.
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Event-Driven Catalytic Degradation at Low Concentrations
