scholarly journals New Synthetic Lethality Re-Sensitizing Platinum-Refractory Cancer Cells to Cisplatin In Vitro: The Rationale to Co-Use PARP and ATM Inhibitors

2021 ◽  
Vol 22 (24) ◽  
pp. 13324
Author(s):  
Watson P. Folk ◽  
Alpana Kumari ◽  
Tetsushi Iwasaki ◽  
Erica K. Cassimere ◽  
Slovénie Pyndiah ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Cancer Cells ◽  
Cisplatin Resistance ◽  
Synthetic Lethality ◽  
Lethal Effect ◽  
Parp Inhibition ◽  
Synthetic Lethal ◽  
Cisplatin Sensitivity ◽  
Platinum Refractory

The pro-apoptotic tumor suppressor BIN1 inhibits the activities of the neoplastic transcription factor MYC, poly (ADP-ribose) polymerase-1 (PARP1), and ATM Ser/Thr kinase (ATM) by separate mechanisms. Although BIN1 deficits increase cancer-cell resistance to DNA-damaging chemotherapeutics, such as cisplatin, it is not fully understood when BIN1 deficiency occurs and how it provokes cisplatin resistance. Here, we report that the coordinated actions of MYC, PARP1, and ATM assist cancer cells in acquiring cisplatin resistance by BIN1 deficits. Forced BIN1 depletion compromised cisplatin sensitivity irrespective of Ser15-phosphorylated, pro-apoptotic TP53 tumor suppressor. The BIN1 deficit facilitated ATM to phosphorylate the DNA-damage-response (DDR) effectors, including MDC1. Consequently, another DDR protein, RNF8, bound to ATM-phosphorylated MDC1 and protected MDC1 from caspase-3-dependent proteolytic cleavage to hinder cisplatin sensitivity. Of note, long-term and repeated exposure to cisplatin naturally recapitulated the BIN1 loss and accompanying RNF8-dependent cisplatin resistance. Simultaneously, endogenous MYC was remarkably activated by PARP1, thereby repressing the BIN1 promoter, whereas PARP inhibition abolished the hyperactivated MYC-dependent BIN1 suppression and restored cisplatin sensitivity. Since the BIN1 gene rarely mutates in human cancers, our results suggest that simultaneous inhibition of PARP1 and ATM provokes a new BRCAness-independent synthetic lethal effect and ultimately re-establishes cisplatin sensitivity even in platinum-refractory cancer cells.

scholarly journals RAD52 as a Potential Target for Synthetic Lethality-Based Anticancer Therapies

Cancers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1561 ◽  
Author(s):  
Toma ◽  
Sullivan-Reed ◽  
Śliwiński ◽  
Skorski
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Synthetic Lethality ◽  
Lethal Effect ◽  
Drug Induced ◽  
Synthetic Lethal ◽  
Repair Mechanisms ◽  
Cancer Tumor

Alterations in DNA repair systems play a key role in the induction and progression of cancer. Tumor-specific defects in DNA repair mechanisms and activation of alternative repair routes create the opportunity to employ a phenomenon called “synthetic lethality” to eliminate cancer cells. Targeting the backup pathways may amplify endogenous and drug-induced DNA damage and lead to specific eradication of cancer cells. So far, the synthetic lethal interaction between BRCA1/2 and PARP1 has been successfully applied as an anticancer treatment. Although PARP1 constitutes a promising target in the treatment of tumors harboring deficiencies in BRCA1/2—mediated homologous recombination (HR), some tumor cells survive, resulting in disease relapse. It has been suggested that alternative RAD52-mediated HR can protect BRCA1/2-deficient cells from the accumulation of DNA damage and the synthetic lethal effect of PARPi. Thus, simultaneous inhibition of RAD52 and PARP1 might result in a robust dual synthetic lethality, effectively eradicating BRCA1/2-deficient tumor cells. In this review, we will discuss the role of RAD52 and its potential application in synthetic lethality-based anticancer therapies.

scholarly journals Cytocidal Antitumor Effects against Human Ovarian Cancer Cells Induced by B-Lactam Steroid Alkylators with Targeted Activity against Poly (ADP-Ribose) Polymerase (PARP) Enzymes in a Cell-Free Assay

Biomedicines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1028
Author(s):  
Nikolaos Nikoleousakos ◽  
Panagiotis Dalezis ◽  
Aikaterini Polonifi ◽  
Elena G. Geromichalou ◽  
Sofia Sagredou ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Mrna Expression ◽  
Cancer Cells ◽  
Cell Lines ◽  
Synthetic Lethality ◽  
Parp Inhibitor ◽  
Positive Control ◽  
Ovarian Cancer Cells ◽  
Antitumor Effects

We evaluated three newly synthesized B-lactam hybrid homo-aza-steroidal alkylators (ASA-A, ASA-B and ASA-C) for their PARP1/2 inhibition activity and their DNA damaging effect against human ovarian carcinoma cells. These agents are conjugated with an alkylating component (POPA), which also served as a reference molecule (positive control), and were tested against four human ovarian cell lines in vitro (UWB1.289 + BRCA1, UWB1.289, SKOV-3 and OVCAR-3). The studied compounds were thereafter compared to 3-AB, a known PARP inhibitor, as well as to Olaparib, a standard third-generation PARP inhibitor, on a PARP assay investigating their inhibitory potential. Finally, a PARP1 and PARP2 mRNA expression analysis by qRT-PCR was produced in order to measure the absolute and the relative gene expression (in mRNA transcripts) between treated and untreated cells. All the investigated hybrid steroid alkylators and POPA decreased in vitro cell growth differentially, according to the sensitivity and different gene characteristics of each cell line, while ASA-A and ASA-B presented the most significant anticancer activity. Both these compounds induced PARP1/2 enzyme inhibition, DNA damage (alkylation) and upregulation of PARP mRNA expression, for all tested cell lines. However, ASA-C underperformed on average in the above tasks, while the compound ASA-B induced synthetic lethality effects on the ovarian cancer cells. Nevertheless, the overall outcome, leading to a drug-like potential, provides strong evidence toward further evaluation.

scholarly journals Geldanamycin-Derived HSP90 Inhibitors Are Synthetic Lethal with NRF2

2020 ◽  
Vol 40 (22) ◽  
Author(s):  
Liam Baird ◽  
Takafumi Suzuki ◽  
Yushi Takahashi ◽  
Eiji Hishinuma ◽  
Daisuke Saigusa ◽  
...  
Keyword(s):  
Target Genes ◽  
Synthetic Lethality ◽  
Drug Repositioning ◽  
Lethal Effect ◽  
Cancer Therapies ◽  
Dependent Manner ◽  
Hsp90 Inhibitors ◽  
Synthetic Lethal ◽  
Activating Mutations ◽  
Approved Drugs

ABSTRACT Activating mutations in KEAP1-NRF2 are frequently found in tumors of the lung, esophagus, and liver, where they are associated with aggressive growth, resistance to cancer therapies, and low overall survival. Despite the fact that NRF2 is a validated driver of tumorigenesis and chemotherapeutic resistance, there are currently no approved drugs which can inhibit its activity. Therefore, there is an urgent clinical need to identify NRF2-selective cancer therapies. To this end, we developed a novel synthetic lethal assay, based on fluorescently labeled isogenic wild-type and Keap1 knockout cell lines, in order to screen for compounds which selectively kill cells in an NRF2-dependent manner. Through this approach, we identified three compounds based on the geldanamycin scaffold which display synthetic lethality with NRF2. Mechanistically, we show that products of NRF2 target genes metabolize the quinone-containing geldanamycin compounds into more potent HSP90 inhibitors, which enhances their cytotoxicity while simultaneously restricting the synthetic lethal effect to cells with aberrant NRF2 activity. As all three of the geldanamycin-derived compounds have been used in clinical trials, they represent ideal candidates for drug repositioning to target the currently untreatable NRF2 activity in cancer.

scholarly journals Advances and perspectives of PARP inhibitors

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Ming Yi ◽  
Bing Dong ◽  
Shuang Qin ◽  
Qian Chu ◽  
Kongming Wu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Cancer Cells ◽  
Genome Instability ◽  
Single Gene ◽  
High Sensitivity ◽  
Lethal Effect ◽  
Single Strand Break ◽  
Synthetic Lethal ◽  
Increased Risk

Abstract DNA damage repair deficiency leads to the increased risk of genome instability and oncogenic transformation. In the meanwhile, this deficiency could be exploited for cancer treatment by inducing excessive genome instability and catastrophic DNA damage. Continuous DNA replication in cancer cells leads to higher demand of DNA repair components. Due to the oncogenic loss of some DNA repair effectors (e.g. BRCA) and incomplete DNA repair repertoire, some cancer cells are addicted to certain DNA repair pathways such as Poly (ADP-ribose) polymerase (PARP)-related single-strand break repair pathway. The interaction between BRCA and PARP is a form of synthetic lethal effect which means the simultaneously functional loss of two genes lead to cell death, while defect in any single gene has a slight effect on cell viability. Based on synthetic lethal theory, Poly (ADP-ribose) polymerase inhibitor (PARPi) was developed aiming to selectively target cancer cells harboring BRCA1/2 mutations. Recently, a growing body of evidence indicated that a broader population of patients could benefit from PARPi therapy far beyond those with germline BRCA1/2 mutated tumors. Numerous biomarkers including homologous recombination deficiency and high level of replication pressure also herald high sensitivity to PARPi treatment. Besides, a series of studies indicated that PARPi-involved combination therapy such as PARPi with additional chemotherapy therapy, immune checkpoint inhibitor, as well as targeted agent had a great advantage in overcoming PARPi resistance and enhancing PARPi efficacy. In this review, we summarized the advances of PARPi in clinical application. Besides, we highlighted multiple promising PARPi-based combination strategies in preclinical and clinical studies.

scholarly journals Mortaparib, a novel dual inhibitor of mortalin and PARP1, is a potential drug candidate for ovarian and cervical cancers

2019 ◽  
Vol 38 (1) ◽  
Author(s):  
Jayarani F. Putri ◽  
Priyanshu Bhargava ◽  
Jaspreet Kaur Dhanjal ◽  
Tomoko Yaguchi ◽  
Durai Sundar ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Growth Arrest ◽  
Suppressor Activity ◽  
Dual Inhibitor ◽  
Tumor Suppressor Activity ◽  
And Migration

Abstract Background Mortalin is enriched in a large variety of cancers and has been shown to contribute to proliferation and migration of cancer cells in multiple ways. It has been shown to bind to p53 protein in cell cytoplasm and nucleus causing inactivation of its tumor suppressor activity in cancer cells. Several other activities of mortalin including mitochondrial biogenesis, ATP production, chaperoning, anti-apoptosis contribute to pro-proliferative and migration characteristics of cancer cells. Mortalin-compromised cancer cells have been shown to undergo apoptosis in in vitro and in vivo implying that it could be a potential target for cancer therapy. Methods We implemented a screening of a chemical library for compounds with potential to abrogate cancer cell specific mortalin-p53 interactions, and identified a new compound (named it as Mortaparib) that caused nuclear enrichment of p53 and shift in mortalin from perinuclear (typical of cancer cells) to pancytoplasmic (typical of normal cells). Biochemical and molecular assays were used to demonstrate the effect of Mortaparib on mortalin, p53 and PARP1 activities. Results Molecular homology search revealed that Mortaparib is a novel compound that showed strong cytotoxicity to ovarian, cervical and breast cancer cells. Bioinformatics analysis revealed that although Mortaparib could interact with mortalin, its binding with p53 interaction site was not stable. Instead, it caused transcriptional repression of mortalin leading to activation of p53 and growth arrest/apoptosis of cancer cells. By extensive computational and experimental analyses, we demonstrate that Mortaparib is a dual inhibitor of mortalin and PARP1. It targets mortalin, PARP1 and mortalin-PARP1 interactions leading to inactivation of PARP1 that triggers growth arrest/apoptosis signaling. Consistent with the role of mortalin and PARP1 in cancer cell migration, metastasis and angiogenesis, Mortaparib-treated cells showed inhibition of these phenotypes. In vivo tumor suppression assays showed that Mortaparib is a potent tumor suppressor small molecule and awaits clinical trials. Conclusion These findings report (i) the discovery of Mortaparib as a first dual inhibitor of mortalin and PARP1 (both frequently enriched in cancers), (ii) its molecular mechanism of action, and (iii) in vitro and in vivo tumor suppressor activity that emphasize its potential as an anticancer drug.

scholarly journals A CRISPR Interference of CBP and p300 Selectively Induced Synthetic Lethality in Bladder Cancer Cells In Vitro

2019 ◽  
Vol 15 (6) ◽  
pp. 1276-1286 ◽  
Author(s):  
Jianfa Li ◽  
ChenChen Huang ◽  
Tiefu Xiong ◽  
Changshui Zhuang ◽  
Chengle Zhuang ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Cancer Cells ◽  
Synthetic Lethality ◽  
Crispr Interference ◽  
Bladder Cancer Cells

scholarly journals The m6A RNA demethylase FTO is a HIF-independent synthetic lethal partner with the VHL tumor suppressor

2020 ◽  
Vol 117 (35) ◽  
pp. 21441-21449 ◽  
Author(s):  
Yiren Xiao ◽  
Kaushik N. Thakkar ◽  
Hongjuan Zhao ◽  
James Broughton ◽  
Yang Li ◽  
...  
Keyword(s):  
Renal Cell Carcinoma ◽  
Tumor Suppressor ◽  
Cell Carcinoma ◽  
Renal Cell ◽  
Metabolic Reprogramming ◽  
Integrated Analysis ◽  
Antiangiogenic Agents ◽  
Synthetic Lethal

Loss of the von Hippel–Lindau (VHL) tumor suppressor is a hallmark feature of renal clear cell carcinoma. VHL inactivation results in the constitutive activation of the hypoxia-inducible factors (HIFs) HIF-1 and HIF-2 and their downstream targets, including the proangiogenic factors VEGF and PDGF. However, antiangiogenic agents and HIF-2 inhibitors have limited efficacy in cancer therapy due to the development of resistance. Here we employed an innovative computational platform, Mining of Synthetic Lethals (MiSL), to identify synthetic lethal interactions with the loss of VHL through analysis of primary tumor genomic and transcriptomic data. Using this approach, we identified a synthetic lethal interaction between VHL and the m6A RNA demethylase FTO in renal cell carcinoma. MiSL identified FTO as a synthetic lethal partner of VHL because deletions of FTO are mutually exclusive with VHL loss in pan cancer datasets. Moreover, FTO expression is increased in VHL-deficient ccRCC tumors compared to normal adjacent tissue. Genetic inactivation of FTO using multiple orthogonal approaches revealed that FTO inhibition selectively reduces the growth and survival of VHL-deficient cells in vitro and in vivo. Notably, FTO inhibition reduced the survival of both HIF wild type and HIF-deficient tumors, identifying FTO as an HIF-independent vulnerability of VHL-deficient cancers. Integrated analysis of transcriptome-wide m6A-seq and mRNA-seq analysis identified the glutamine transporter SLC1A5 as an FTO target that promotes metabolic reprogramming and survival of VHL-deficient ccRCC cells. These findings identify FTO as a potential HIF-independent therapeutic target for the treatment of VHL-deficient renal cell carcinoma.

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