LXRepair aims to revolutionize personalized medicine by introducing a new approach for diagnostics and treatment selection
Overview

Our focus on function makes us unique!

Innovative method
Tumor biopsy, blood cells

Tumor biopsy
Blood cells

DNA Repair enzymes with series of lesion containing DNA on a biochip

DNA Repair enzymes contained in a biological sample in contact with series of lesion-containing DNA on a biochip.

Repair reaction measured on lesions by fluorescence analysis

Fluorescence analysis reveals the repair reaction occurring at each lesion site.

Profile of DNA Repair mechanisms for each patient

The efficiency and accuracy of the DNA Repair mechanisms is profiled for each patient.
This profiling provides insights into the  patient' ability to respond to a treatment.

Traditionnal Method
Tumor biopsy, blood cells
Tumor biopsy
Blood cells
Genomics NGS, SNPs
Genomics
NGS, SNPs
DNA repair Sequencing
 
Profile of DNA Repair mechanisms for each patient
Each patient's mutational profile determines which therapies are prescribed. Due to redundancy and complexity of pathways, treatment fails for about 20% of patients receiving the therapy.

Focusing on function rather than on genes

We focus on functional profiling rather than on genomic profiling

Why?
Genomic profiling provides oncologists with theoretical information to inform their therapeutic decision-making. However, it provides no insight into how everything works together and how each task is executed.
Image
Because DNA Repair and DDR proteins are regulated by post-translational modifications and are part of a complex kinases signalling cascade, our functional approach provides more relevant information than the genomic approach.
In addition, the result takes all possible molecular regulation into account (epigenetic, transcription, pathway reactivation, etc).
LXRepair DNA Repair Enzymatic profiling, by offering a comprehensive analysis of DDR and DNA repair mechanisms can complement genetic tools to provide a more dynamic insight into a patient's ability to respond to a treatment.

DNA Repair mechanisms, DDR and cancer treatments, an integrated view

DNA Repair and DNA Damage Response are part of a large functional network controlled by kinase cascades.
Major genes in these networks are frequently mutated in cancers.
  • Mutations in the signaling cascade have functional consequences that affect DNA Repair and DDR in different ways. 
  • The DNA Repair Enzyme Signature reflects the impact of driver mutations in the signaling cascade. 
  • Driver mutations in the signaling cascade and mutations in DNA Repair or DDR genes determine the response to cytotoxic drugs, radiotherapy, targeted therapies and DNA Repair inhibitors.
  • Pathway redundancy makes the system very complex and the functional approach highly relevant.
DNA Repair mechanisms, DDR: LXRepair expertise, image scheme

DNA Repair: a biomarker of targeted therapies (MAPK pathway)

We test how targeted therapies affect DNA Repair to reveal pathways connections. Mutations with an impact early in signaling pathways can affect DNA Repair, but sometimes cause reactivation of parallel pathway, profoundly altering the impact of targeted therapies.
Treatment should counteract pathway activation as a result of mutations in driving genes.
This type of effect is normally translated at the DNA Repair level.
By checking the DNA Repair signature before and after treatment, we can confirm the pathway's deactivation.

DNA Repair and response to immunotherapy

Tumors with disabled DNA Repair systems have better chance to respond to immunotherapy. LXRepair platform can give a real time comprehensive overview of DNA Repair defects potentially leading to increased mutant proteins recognized by the immune system.

DNA Repair inhibitors

DDR and DNA Repair proteins are potential targets for the development of potent inhibitors. The LXRepair assays can be used to check inhibitors mechanisms of action and specificity. They are suited to stratify patients response and identify compensatory mechanisms responsible for resistance to inhibitors.

Synthetic lethality and cancer

Cancer is by definition a disease of DNA repair. Mutations in DNA repair genes can cause a loss of function that in certain cases is compensated by alternative or redundant pathways.
The concept of synthetic lethality is based on the inhibition of the alternative routes leading to the loss of function essential for cell survival and consequently to tumor cell death.
PARP inhibitors effectively kill tumors defective in homologous recombination pathway through the concept of synthetic lethality.

However, PARP inhibitors also show significant clinical benefit in patients without HR deficiencies.
Although some patients have sustained response to PARPi, resistance to PARPi arises in advanced disease.

LXRepair technologies can be used to check for the effective inhibition of specific DNA Repair pathways and can control the absence of any activity restoration potentially leading to resistance.

Particular case of DNA repair responses to PARP inhibition

Synthetic lethality and cancer scheme
Technology

SPOT-LX™ platform technology

Profiling DNA Repair

Series of DNA substrates containing specific lesions are immobilized on biochips. The samples to be characterized are processed and extracts are applied to the biochip. The DNA Repair enzymes present in the sample repair their different substrates and generate fluorescent changes on the biochip, yielding a specific signature for each sample.
Our quantitative functional multiplex on-chip assays mimic what happens in the cell.
SPOT-LX platform technology: profiling DNA Repair
SPOT-LX platform technology scheme
Rapid results: 1 day (blood cells) or 2 days (biopsy)

Multiple Advantages of our functional multiplex approach

  • Reflects DNA Repair in real time
    More relevant than genomic technologies
  • Characterizes the whole DNA Repair network
    More powerful than single parameter assays
  • Integrates all molecular regulations in a single read-out

Our assays cover most DNA Repair pathways

3 complementary assays to cover most DNA Repair pathways and gain insights into major DNA Repair processes

  • adapted to each therapeutic strategy
  • designed with DNA Repair complexity in mind
  • precise, complete and specific
Applications

LXRepair Assays and Clinical Diagnostics Applications

LXRepair Assays and Clinical Diagnostics Applications
BER: Base Excision Repair
NER: Nucleotide Excision Repair
ICLR: Intra-Crosslink Repair
NHEJ: Non Homologous End Joining
HR: Homologous Recombination

Glyco-SPOT applications

Radiotoxicity
Inflammation
DNA Repair inhibitor development
DNA Repair inhibitor resistance

ExSy-SPOT applications

Tumor Stratification
DNA Repair inhibitor development
DNA Repair inhibitor resistance
Response to immunotherapy
Response to chemotherapy
Response to radiotherapy
Response to targeted therapy

Next-SPOT applications

Tumor Stratification
DNA Repair inhibitor development
DNA Repair inhibitor resistance
DNA Repair

DNA Repair

Base Excision Repair illustration

Base Excision Repair

BER relies on Glycosylases to recognize and cleave "small" base lesions produced by alkylation, oxidation or deamination of normal DNA bases. The resulting abasic sites (AP sites) are then processed by an AP endonuclease. Bifunctional glycosylases display intrinsic AP lyase activity. The resulting gap is filled through the action of polymerases and finaly ligated.

Each glycosylase has a specific substrate spectrum.

LXRepair's Glyco-SPOT assay investigates repair enzymes by examining the substrates cleaved.
Lesions/paired base
8oxoG/C
A/8oxoG
U/G
U/A
Tg/A
Hx/T
EthenoA/T
AP site (THF)/T
Human Glycosylase
hOGG1
hMYH
SMUG, UNG
UNG
hNTH1, NEIL1
MPG
MPG
APE1
Nucleotide Excision Repair illustration

Nucleotide Excision Repair

NER removes a variety of DNA damage including helix-distorting lesions such as photoproducts and bulky lesions. It contributes to the removal of Inter-Strand Crosslinks.
Specific damage-sensing factors, including DDB1, DDB2, and XPC-hHR23B are involved in damage recognition (Global Genome Repair – GGR).
Depending on the structure of the lesion, different damage recognition factors and damage recognition factor enhancers are involved. Transcription-Coupled Repair (TCR) is initiated when RNA polymerase II stalls at a lesion. CSA and CSB are additional factors required for effective TCR. Transcription factor IIH (TFIIH) is recruited to the damaged site. XPA-RPA verifies whether the NER complex is correctly assembled, and helicases XPB and XPD unwind the double-helix. A short single-stranded DNA segment containing the lesion is then removed after incision by the endonucleases XPG and XPF-ERCC1. DNA polymerases fill the gap using the complementary sequence as a template. Finally, a DNA Ligase performs ligation.
Double Strand Breaks Repair illustration

Double-Strand Break Repair

DNA double-strand breaks (DSBs) are generated by ionizing radiations or endogenously during the replication process. They are among the most severe kinds of DNA damage.

DSBs are repaired through 2 main mechanisms that can operate in parallel or in competition, with various kinetics and outcomes: Homologous Recombination (HR) and Non-Homologous End Joining (NHEJ). NHEJ which is active through the whole cell cycle, is the predominant repair pathway. Alternative pathways such as Single-Strand Annealing (SSA) and alternative end joining pathways are also described. HR requires long homologous sequences and is predominantly error-free, while NHEJ tends to operate faster in a template-independent manner, at the cost of sequence alterations. SSA requires homologies flanking the DSB for operation and is a highly mutagenic process generating large deletions.