scholarly journals Cutting down the time to identify challenging tumor therapeutic targets and drug combinations using synthetic lethal approaches

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 308 ◽  
Author(s):  
John S. Lazo
Keyword(s):  
Drug Targets ◽  
Gene Mutations ◽  
Cancer Therapeutics ◽  
Drug Combinations ◽  
Cancer Drug ◽  
Loss Of Function ◽  
Synthetic Lethal ◽  
Optimal Drug

Cancer drug discoverers and developers are blessed and cursed with a plethora of drug targets in the tumor cells themselves and the surrounding stromal elements. This bounty of targets has, at least in part, inspired the rapid increase in the number of clinically available small-molecule, biological, and cellular therapies for solid and hematological malignancies. Among the most challenging questions in cancer therapeutics, especially for small molecules, is how to approach loss-of-function gene mutations or deletions that encode tumor suppressors. A second mounting question is what are the optimal drug combinations. This article will briefly review the recent advances in exploiting in vitro and in vivo synthetic lethal screens to expose cancer pharmacological targets with the goal of developing new drug combinations.

scholarly journals Development of A Novel Highly Selective TLR8 Agonist for Cancer Immunotherapy

2020 ◽  
Author(s):  
Yuxun Wang ◽  
Heping Yang ◽  
Huanping Li ◽  
Shuda Zhao ◽  
Yikun Zeng ◽  
...  
Keyword(s):  
Immune Responses ◽  
Drug Targets ◽  
Ex Vivo ◽  
Single Agent ◽  
Cancer Drug ◽  
Phase I Clinical Trials ◽  
Tlr Agonists ◽  
Favorable Safety

ABSTRACTToll-like receptors (TLRs) are a family of proteins that recognize pathogen associated molecular patterns (PAMPs). Their primary function is to activate innate immune responses while also involved in facilitating adaptive immune responses. Different TLRs exert distinct functions by activating varied immune cascades. Several TLRs are being pursued as cancer drug targets. We discovered a novel, highly potent and selective small molecule TLR8 agonist DN052. DN052 exhibited strong in vitro cellular activity with EC50 at 6.7 nM and was highly selective for TLR8 over other TLRs including TLR4, 7 and 9. The selectivity profile distinguished DN052 from all other TLR agonists currently in clinical development. DN052 displayed excellent in vitro ADMET and in vivo PK profiles. DN052 potently inhibited tumor growth as a single agent. Moreover, combination of DN052 with the immune checkpoint inhibitor, selected targeted therapeutics or chemotherapeutic drugs further enhanced efficacy of single agents. Mechanistically, treatment with DN052 resulted in strong induction of pro-inflammatory cytokines in ex vivo human PBMC assay and in vivo monkey study. GLP toxicity studies in rats and monkeys demonstrated favorable safety profile. This led to the advancement of DN052 into phase I clinical trials.

scholarly journals Combining CRISPR/Cas9 mutagenesis and a small-molecule inhibitor to probe the function of MELK in cancer

2017 ◽  
Author(s):  
Christopher J. Giuliano ◽  
Ann Lin ◽  
Joan C. Smith ◽  
Ann C. Palladino ◽  
Jason M. Sheltzer
Keyword(s):  
Drug Targets ◽  
Leucine Zipper ◽  
Chemotherapy Resistance ◽  
Cancer Drug ◽  
Cell Renewal ◽  
Multiple Cancer ◽  
Clinical Prognosis ◽  
Phenotype Analysis

AbstractThe Maternal Embryonic Leucine Zipper Kinase (MELK) has been identified as a promising therapeutic target in multiple cancer types. MELK over-expression is associated with aggressive disease, and MELK has been implicated in numerous cancer-related processes, including chemotherapy resistance, stem cell renewal, and tumor growth. On the basis of these findings, a MELK inhibitor is currently being tested in several clinical trials. Here, we report that cancer cell lines harboring CRISPR/Cas9-induced null mutations in MELK exhibit wild-type growthin vitro, under environmental stress, in the presence of multiple chemotherapy agents, andin vivo. By combining our MELK-knockout clones with a recently-described, highly-specific MELK inhibitor, we further demonstrate that the acute inhibition of MELK results in no specific anti-proliferative phenotype. Analysis of gene expression data from cohorts of cancer patients identifies MELK expression as a correlate of tumor mitotic activity, explaining its association with poor clinical prognosis. In total, our results demonstrate the power of CRISPR/Cas9-based genetic approaches to investigate cancer drug targets, and call into question the rationale for treating patients with anti-MELK monotherapies.

scholarly journals Synthetic lethality-based prediction of anti-SARS-CoV-2 targets

2021 ◽  
Author(s):  
Lipika R. Pal ◽  
Kuoyuan Cheng ◽  
Nishanth U Nair ◽  
Laura Martin-Sancho ◽  
Sanju Sinha ◽  
...  
Keyword(s):  
Drug Targets ◽  
Synthetic Lethality ◽  
Host Cells ◽  
Synthetic Lethal ◽  
Viral Propagation ◽  
In Vivo Testing ◽  
Altered Gene ◽  
Host Genes

Novel strategies are needed to identify drug targets and treatments for the COVID-19 pandemic. The altered gene expression of virus-infected host cells provides an opportunity to specifically inhibit viral propagation via targeting the synthetic lethal (SL) partners of such altered host genes. Pursuing this antiviral strategy, here we comprehensively analyzed multiple in vitro and in vivo bulk and single-cell RNA-sequencing datasets of SARS-CoV-2 infection to predict clinically relevant candidate antiviral targets that are SL with altered host genes. The predicted SL-based targets are highly enriched for infected cell inhibiting genes reported in four SARS-CoV-2 CRISPR-Cas9 genome-wide genetic screens. Integrating our predictions with the results of these screens, we further selected a focused subset of 26 genes that we experimentally tested in a targeted siRNA screen using human Caco-2 cells. Notably, as predicted, knocking down these targets reduced viral replication and cell viability only under the infected condition without harming non-infected cells. Our results are made publicly available, to facilitate their in vivo testing and further validation.

scholarly journals Do alterations in gene expressions influence tumorigenesis in the transmissible venereal tumor in dogs?

2020 ◽  
Vol 50 (11) ◽  
Author(s):  
Haline Ballestero Fêo ◽  
Luis Mauricio Montoya Flórez ◽  
Ricardo Seiti Yamatogi ◽  
Anderson do Prado Duzanski ◽  
João Pessoa Araújo Junior ◽  
...  
Keyword(s):  
Cell Culture ◽  
Tumor Suppressor Genes ◽  
Primary Cell Culture ◽  
Gene Mutations ◽  
Tp53 Gene ◽  
Primary Cell ◽  
Loss Of Function ◽  
Gene Expressions

ABSTRACT: Canine transmissible venereal tumor (CTVT) is a transmissible neoplasm, which spreads naturally between dogs through the halogenic transfer of tumor cells, mainly during coitus. It is the oldest known tumoral lineage in nature and reports on gene mutations have been extended. Also, this tumor shares several genetic mutations with some cancers in humans, among them lung carcinomas, melanoma, prostate, breast, among other cancers. Thus, expression of tumor suppressor genes such as TP53, P21, and apoptosis-related genes such as BAX, BCL-2, and BCL-xL, both in vivo and in vitro (primary cell culture) were quantified. In the present study, the comparison of gene expression, the TP53 gene, in most cases, was shown to be high in the majority of tissues (65%) and primary cell culture (100%), while BCL-2, BCL-xL, and BAX presented variation among the animals analyzed. Moreover, in these situations, the results suggested that the apoptotic regulation of these genes did not occur for TP53. The P21 gene was shown to be mostly normal (70%); although, absence (6%) and underexpressions (24%) were also observed. Statistical analysis of the BCL-xL gene demonstrated significant differences between the tissues of the animals when compared to the cell cultures; however, to the other genes, no statistical difference was observed between the groups. Preliminarily, the results suggested the presence of alterations in the gene expressions of the TP53, P21, BAX, BCL-2 and BCL-xL leading to loss of function in these genes, which affect the tumorigenesis of CTVT.

scholarly journals Development of a novel TLR8 agonist for cancer immunotherapy

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Yuxun Wang ◽  
Heping Yang ◽  
Huanping Li ◽  
Shuda Zhao ◽  
Yikun Zeng ◽  
...  
Keyword(s):  
Immune Responses ◽  
Drug Targets ◽  
Ex Vivo ◽  
Phase 1 ◽  
Single Agent ◽  
Cancer Drug ◽  
Favorable Safety ◽  
Molecular Patterns

Abstract Toll-like receptors (TLRs) are a family of proteins that recognize pathogen associated molecular patterns (PAMPs). Their primary function is to activate innate immune responses while also involved in facilitating adaptive immune responses. Different TLRs exert distinct functions by activating varied immune cascades. Several TLRs are being pursued as cancer drug targets. We discovered a novel, highly potent and selective small molecule TLR8 agonist DN052. DN052 exhibited strong in vitro cellular activity with EC50 at 6.7 nM and was highly selective for TLR8 over other TLRs including TLR4, 7 and 9. DN052 displayed excellent in vitro ADMET and in vivo PK profiles. DN052 potently inhibited tumor growth as a single agent. Moreover, combination of DN052 with the immune checkpoint inhibitor, selected targeted therapeutics or chemotherapeutic drugs further enhanced efficacy of single agents. Mechanistically, treatment with DN052 resulted in strong induction of pro-inflammatory cytokines in ex vivo human PBMC assay and in vivo monkey study. GLP toxicity studies in rats and monkeys demonstrated favorable safety profile. This led to the advancement of DN052 into phase 1 clinical trials.

scholarly journals Current Status of the Use of Multifunctional Enzymes as Anti-Cancer Drug Targets

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 10
Author(s):  
Carla S. S. Teixeira ◽  
Sérgio F. Sousa
Keyword(s):  
Posttranslational Modifications ◽  
Drug Targets ◽  
Current Status ◽  
Cancer Drug ◽  
Cancer Cell Growth ◽  
Anti Cancer ◽  
Multifunctional Enzymes ◽  
Potential Inhibitors

Fighting cancer is one of the major challenges of the 21st century. Among recently proposed treatments, molecular-targeted therapies are attracting particular attention. The potential targets of such therapies include a group of enzymes that possess the capability to catalyze at least two different reactions, so-called multifunctional enzymes. The features of such enzymes can be used to good advantage in the development of potent selective inhibitors. This review discusses the potential of multifunctional enzymes as anti-cancer drug targets along with the current status of research into four enzymes which by their inhibition have already demonstrated promising anti-cancer effects in vivo, in vitro, or both. These are PFK-2/FBPase-2 (involved in glucose homeostasis), ATIC (involved in purine biosynthesis), LTA4H (involved in the inflammation process) and Jmjd6 (involved in histone and non-histone posttranslational modifications). Currently, only LTA4H and PFK-2/FBPase-2 have inhibitors in active clinical development. However, there are several studies proposing potential inhibitors targeting these four enzymes that, when used alone or in association with other drugs, may provide new alternatives for preventing cancer cell growth and proliferation and increasing the life expectancy of patients.

scholarly journals CRISPR screens uncover protective effect of PSTK as a regulator of chemotherapy-induced ferroptosis in hepatocellular carcinoma

2022 ◽  
Vol 21 (1) ◽  
Author(s):  
Yiran Chen ◽  
Li Li ◽  
Jie Lan ◽  
Yang Cui ◽  
Xiaosong Rao ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Synthetic Lethality ◽  
Synergistic Effects ◽  
Loss Of Function ◽  
Protein Coding ◽  
Synthetic Lethal ◽  
Chemotherapeutic Treatment ◽  
Hcc Cells

Abstract Background Hepatocellular carcinoma (HCC) is among the most common forms of cancer and is associated with poor patient outcomes. The emergence of therapeutic resistance has hampered the efficacy of targeted treatments employed to treat HCC patients to date. In this study, we conducted a series of CRISPR/Cas9 screens to identify genes associated with synthetic lethality capable of improving HCC patient clinical responses. Methods CRISPR-based loss-of-function genetic screens were used to target 18,053 protein-coding genes in HCC cells to identify chemotherapy-related synthetic lethal genes in these cells. Synergistic effects were analyzed through in vitro and in vivo analyses, while related mechanisms were explored through RNA-seq and metabolomics analyses. Potential inhibitors of identified genetic targets were selected through high-throughput virtual screening. Results The inhibition of phosphoseryl-tRNA kinase (PSTK) was found to increase HCC cell sensitivity to chemotherapeutic treatment. PSTK was associated with the suppression of chemotherapy-induced ferroptosis in HCC cells, and the depletion of PSTK resulted in the inactivation of glutathione peroxidative 4 (GPX4) and the disruption of glutathione (GSH) metabolism owing to the inhibition of selenocysteine and cysteine synthesis, thus enhancing the induction of ferroptosis upon targeted chemotherapeutic treatment. Punicalin, an agent used to treat hepatitis B virus (HBV), was identified as a possible PSTK inhibitor that exhibited synergistic efficacy when applied together with Sorafenib to treat HCC in vitro and in vivo. Conclusions These results highlight a key role for PSTK as a mediator of resistance to targeted therapeutic treatment in HCC cells that functions by suppressing ferroptotic induction. PSTK inhibitors may thus represent ideal candidates for overcoming drug resistance in HCC.

scholarly journals Cross-Species Complementation of Nonessential Yeast Genes Establishes Platforms for Testing Inhibitors of Human Proteins

Genetics ◽  
2020 ◽  
Vol 214 (3) ◽  
pp. 735-747 ◽  
Author(s):  
Akil Hamza ◽  
Maureen R. M. Driessen ◽  
Erik Tammpere ◽  
Nigel J. O’Neil ◽  
Philip Hieter
Keyword(s):  
Drug Targets ◽  
Chromosome Instability ◽  
Yeast Complementation ◽  
Synthetic Lethal ◽  
Link Type ◽  
Human Proteins ◽  
Species Specific ◽  
Yeast Genes

Cross-species complementation can be used to generate humanized yeast, which is a valuable resource with which to model and study human biology. Humanized yeast can be used as an in vivo platform to screen for chemical inhibition of human protein drug targets. To this end, we report the systematic complementation of nonessential yeast genes implicated in chromosome instability (CIN) with their human homologs. We identified 20 human–yeast complementation pairs that are replaceable in 44 assays that test rescue of chemical sensitivity and/or CIN defects. We selected a human–yeast pair (hFEN1/yRAD27), which is frequently overexpressed in cancer and is an anticancer therapeutic target, to perform in vivo inhibitor assays using a humanized yeast cell-based platform. In agreement with published in vitro assays, we demonstrate that HU-based PTPD is a species-specific hFEN1 inhibitor. In contrast, another reported hFEN1 inhibitor, the arylstibonic acid derivative NSC-13755, was determined to have off-target effects resulting in a synthetic lethal phenotype with yRAD27-deficient strains. Our study expands the list of human–yeast complementation pairs to nonessential genes by defining novel cell-based assays that can be utilized as a broad resource to study human drug targets.

scholarly journals Advancements in 3D Cell Culture Systems for Personalizing Anti-Cancer Therapies

2021 ◽  
Vol 11 ◽  
Author(s):  
Andrew M. K. Law ◽  
Laura Rodriguez de la Fuente ◽  
Thomas J. Grundy ◽  
Guocheng Fang ◽  
Fatima Valdes-Mora ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
3D Culture ◽  
3D Cell Culture ◽  
Cancer Therapeutics ◽  
Drug Efficacy ◽  
Cancer Drug ◽  
Cancer Therapies ◽  
Anti Cancer

Over 90% of potential anti-cancer drug candidates results in translational failures in clinical trials. The main reason for this failure can be attributed to the non-accurate pre-clinical models that are being currently used for drug development and in personalised therapies. To ensure that the assessment of drug efficacy and their mechanism of action have clinical translatability, the complexity of the tumor microenvironment needs to be properly modelled. 3D culture models are emerging as a powerful research tool that recapitulates in vivo characteristics. Technological advancements in this field show promising application in improving drug discovery, pre-clinical validation, and precision medicine. In this review, we discuss the significance of the tumor microenvironment and its impact on therapy success, the current developments of 3D culture, and the opportunities that advancements that in vitro technologies can provide to improve cancer therapeutics.

An RNAi-based system for loss-of-function analysis identifies Raf1 as a crucial mediator of BCR-ABL–driven leukemogenesis

Blood ◽  
2011 ◽  
Vol 118 (8) ◽  
pp. 2200-2210 ◽  
Author(s):  
Corinna Albers ◽  
Anna L. Illert ◽  
Cornelius Miething ◽  
Hannes Leischner ◽  
Melanie Thiede ◽  
...  
Keyword(s):  
Drug Targets ◽  
Function Analysis ◽  
Expression System ◽  
Hematopoietic Cells ◽  
Mouse Strains ◽  
Loss Of Function ◽  
Tumor Models ◽  
Murine Tumor

Abstract Genetic loss-of-function studies in murine tumor models have been essential in the analysis of downstream mediators of oncogenic transformation. Unfortunately, these studies are frequently limited by the availability of genetically modified mouse strains. Here we describe a versatile method allowing the efficient expression of an oncogene and simultaneous knockdown of targets of interest (TOI) from a single retroviral vector. Both oncogene and TOI-specific miR30-based shRNA are under the control of the strong viral long terminal repeat promoter, resulting in a single shared RNA transcript. Using this vector in a murine syngeneic BM transplantation model for BCR-ABL–induced chronic myeloid leukemia, we find that oncogene expression and target knockdown in primary hematopoietic cells with this vector is efficient both in vitro and in vivo, and demonstrate that Raf1, but not BRAF, modulates BCR-ABL–dependent ERK activation and transformation of hematopoietic cells. This expression system could facilitate genetic loss-of-function studies and allow the rapid validation of potential drug targets in a broad range of oncogene-driven murine tumor models.

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