Search results for "Synthetic lethality"

Individualized Tumor Therapy: Biomarkers and Possibilities for Targeted Therapy with Natural Products

2014

Although many tumors respond to chemotherapy, not all patients benefit from anticancer drugs. Tumors often develop resistance to drugs and concentrations sufficient to eradicate the cancer cannot be used due to the severe side effects of chemotherapy. In the present chapter, we give an overview of research on biomarkers with prognostic and predictive value and summarize our own efforts in this context. With a battery of biomarkers and corresponding synthetic and natural targeted drugs, it is likely that custom-tailored combination treatments will soon become a reality and that each individual cancer patient will be treated based on his or her individual molecular tumor architecture.

Pharmacological targeting of the novel β-catenin chromatin-associated kinase p38α in colorectal cancer stem cell tumorspheres and organoids

2021

AbstractThe prognosis of locally advanced colorectal cancer (CRC) is currently unsatisfactory. This is mainly due to drug resistance, recurrence, and subsequent metastatic dissemination, which are sustained by the cancer stem cell (CSC) population. The main driver of the CSC gene expression program is Wnt signaling, and previous reports indicate that Wnt3a can activate p38 MAPK. Besides, p38 was shown to feed into the canonical Wnt/β-catenin pathway. Here we show that patient-derived locally advanced CRC stem cells (CRC-SCs) are characterized by increased expression of p38α and are “addicted” to its kinase activity. Of note, we found that stage III CRC patients with high p38α levels display…

Dual targeting of higher-order DNA structures by azacryptands induces DNA junction-mediated DNA damage in cancer cells

2021

Abstract DNA is intrinsically dynamic and folds transiently into alternative higher-order structures such as G-quadruplexes (G4s) and three-way DNA junctions (TWJs). G4s and TWJs can be stabilised by small molecules (ligands) that have high chemotherapeutic potential, either as standalone DNA damaging agents or combined in synthetic lethality strategies. While previous approaches have claimed to use ligands that specifically target either G4s or TWJs, we report here on a new approach in which ligands targeting both TWJs and G4s in vitro demonstrate cellular effects distinct from that of G4 ligands, and attributable to TWJ targeting. The DNA binding modes of these new, dual TWJ-/G4-ligands w…

Genetic determinants of ATR inhibitor sensitivity and resistance in Gastric Cancer

2019

Synthetic lethal approaches in identifying genetic determinants of drug response is a powerful method in selecting patents for targeted cancer therapies. Ataxia-Telangiectasia Mutated (ATM) and Rad3-related protein kinase (ATR) is a valuable target to inhibit the DNA damage repair (DDR) pathway, that has been shown to be particularly effective in cancer cells harbouring other DDR defects, including truncating mutations in ARID1A, found in the 20% of gastric cancer (GC) patients. Although ATR inhibitors (ATRi) are emerging as promising cancer therapies, resistance mechanisms inevitably arise from these drugs as monotherapy, emphasising the importance of identifying genetic determinants of re…

“Back to a false normality”: new intriguing mechanisms of resistance to PARP inhibitors

2017

Several evidences have shown that BRCA mutations increased tumor-cells sensitivity to PARP inhibitors by synthetic lethality leading to an accelerated development of several compounds targeting the PARP enzymes system as anticancer agents for clinical setting. Most of such compounds have been investigated in ovarian and breast cancer, showing promising efficacy in BRCA-mutated patients. Recently clinical studies of PARP-inhibitors have been extended across different tumor types harboring BRCA-mutations, including also "BRCA-like" sporadic tumors with homologous recombination deficiency (HRD). This review summarizes the biological background underlying PARP-inhibition, reporting the results …

DNA folds threaten genetic stability and can be leveraged for chemotherapy

2020

International audience; Damaging DNA is a current and efficient strategy to fight against cancer cell proliferation. Numerous mechanisms exist to counteract DNA damage, collectively referred to as the DNA damage response (DDR) and which are commonly dysregulated in cancer cells. Precise knowledge of these mechanisms is necessary to optimise chemotherapeutic DNA targeting. New research on DDR has uncovered a series of promising therapeutic targets, proteins and nucleic acids, with application notably via an approach referred to as combination therapy or combinatorial synthetic lethality. In this review, we summarise the cornerstone discoveries which gave way to the DNA being considered as an…

DNA Junction Ligands Trigger DNA Damage and Are Synthetic Lethal with DNA Repair Inhibitors in Cancer Cells.

2019

International audience; Translocation of DNA and RNA polymerases along their duplex substrates results in DNA supercoiling. This torsional stress promotes the formation of plectonemic structures, including three-way DNA junction (TWJ), which can block DNA transactions and lead to DNA damage. While cells have evolved multiple mechanisms to prevent the accumulation of such structures, stabilizing TWJ through ad hoc ligands offer an opportunity to trigger DNA damage in cells with high level of transcription and replication, such as cancer cells. Here, we develop a series of azacryptand-based TWJ ligands, we thoroughly characterize their TWJ-interacting properties in vitro and demonstrate their…

Network pharmacology of cancer: From understanding of complex interactomes to the design of multi-target specific therapeutics from nature

2015

Despite massive investments in drug research and development, the significant decline in the number of new drugs approved or translated to clinical use raises the question, whether single targeted drug discovery is the right approach. To combat complex systemic diseases that harbour robust biological networks such as cancer, single target intervention is proved to be ineffective. In such cases, network pharmacology approaches are highly useful, because they differ from conventional drug discovery by addressing the ability of drugs to target numerous proteins or networks involved in a disease. Pleiotropic natural products are one of the promising strategies due to their multi-targeting and d…

2018

AbstractThe cell adhesion glycoprotein E-cadherin (CDH1) is commonly inactivated in breast tumors. Precision medicine approaches that exploit this characteristic are not available. Using perturbation screens in breast tumor cells with CRISPR/Cas9-engineered CDH1 mutations, we identified synthetic lethality between E-cadherin deficiency and inhibition of the tyrosine kinase ROS1. Data from large-scale genetic screens in molecularly diverse breast tumor cell lines established that the E-cadherin/ROS1 synthetic lethality was not only robust in the face of considerable molecular heterogeneity but was also elicited with clinical ROS1 inhibitors, including foretinib and crizotinib. ROS1 inhibitor…

Targeting MYCN in Pediatric and Adult Cancers

2021

The deregulation of theMYCfamily of oncogenes, includingc-MYC,MYCNandMYCLoccurs in many types of cancers, and is frequently associated with a poor prognosis. The majority of functional studies have focused onc-MYCdue to its broad expression profile in human cancers. The existence of highly conserved functional domains betweenMYCNandc-MYCsuggests thatMYCNparticipates in similar activities.MYCencodes a basic helix-loop-helix-leucine zipper (bHLH-LZ) transcription factor (TF) whose central oncogenic role in many human cancers makes it a highly desirable therapeutic target. Historically, as a TF, MYC has been regarded as “undruggable”. Thus, recent efforts focus on investigating methods to indi…