Drug repurposing screen identifies lestaurtinib amplifies the ability of the poly (ADP-ribose) polymerase 1 inhibitor AG14361 to kill breast cancer associated gene-1 mutant and wild type breast cancer cells

Applying a Gene Reversal Rate Computational Methodology to Identify Drugs for a Rare Cancer: Inflammatory Breast Cancer

The aim of this study was to utilize a computational methodology based on Gene Reversal Rate (GRR) scoring to repurpose existing drugs for a rare and understudied cancer: inflammatory breast cancer (IBC). This method uses IBC-related gene expression signatures (GES) and drug-induced gene expression profiles from the LINCS database to calculate a GRR score for each candidate drug, and is based on the idea that a compound that can counteract gene expression changes of a disease may have potential therapeutic applications for that disease. Genes related to IBC with associated differential expression data (265 up-regulated and 122 down-regulated) were collated from PubMed-indexed publications. Drug-induced gene expression profiles were downloaded from the LINCS database and candidate drugs to treat IBC were predicted using their GRR scores. Thirty-two (32) drug perturbations that could potentially reverse the pre-compiled list of 297 IBC genes were obtained using the LINCS Canvas Browser (LCB) analysis. Binary combinations of the 32 perturbations were assessed computationally to identify combined perturbations with the highest GRR scores, and resulted in 131 combinations with GRR greater than 80%, that reverse up to 264 of the 297 genes in the IBC-GES. The top 35 combinations involve 20 unique individual drug perturbations, and 19 potential drug candidates. A comprehensive literature search confirmed 17 of the 19 known drugs as having either anti-cancer or anti-inflammatory activities. AZD-7545, BMS-754807, and nimesulide target known IBC relevant genes: PDK, Met, and COX, respectively. AG-14361, butalbital, and clobenpropit are known to be functionally relevant in DNA damage, cell cycle, and apoptosis, respectively. These findings support the use of the GRR approach to identify drug candidates and potential combination therapies that could be used to treat rare diseases such as IBC.

MicroRNA-Based Discovery of Biomarkers, Therapeutic Targets, and Repositioning Drugs for Breast Cancer

Breast cancer treatment can be improved with biomarkers for early detection and individualized therapy. A set of 86 microRNAs (miRNAs) were identified to separate breast cancer tumors from normal breast tissues (n = 52) with an overall accuracy of 90.4%. Six miRNAs had concordant expression in both tumors and breast cancer patient blood samples compared with the normal control samples. Twelve miRNAs showed concordant expression in tumors vs. normal breast tissues and patient survival (n = 1093), with seven as potential tumor suppressors and five as potential oncomiRs. From experimentally validated target genes of these 86 miRNAs, pan-sensitive and pan-resistant genes with concordant mRNA and protein expression associated with in-vitro drug response to 19 NCCN-recommended breast cancer drugs were selected. Combined with in-vitro proliferation assays using CRISPR-Cas9/RNAi and patient survival analysis, MEK inhibitors PD19830 and BRD-K12244279, pilocarpine, and tremorine were discovered as potential new drug options for treating breast cancer. Multi-omics biomarkers of response to the discovered drugs were identified using human breast cancer cell lines. This study presented an artificial intelligence pipeline of miRNA-based discovery of biomarkers, therapeutic targets, and repositioning drugs that can be applied to many cancer types.

PARP-1: a critical regulator in radioprotection and radiotherapy-mechanisms, challenges, and therapeutic opportunities

Background: Since its discovery, poly (ADP-ribose) polymerase 1 (PARP-1) has been extensively studied due to its regulatory role in numerous biologically crucial pathways. PARP inhibitors have opened new therapeutic avenues for cancer patients and have gained approval as standalone treatments for certain types of cancer. With continued advancements in the research of PARP inhibitors, we can fully realize their potential as therapeutic targets for various diseases. Purpose: To assess the current understanding of PARP-1 mechanisms in radioprotection and radiotherapy based on the literature. Methods: We searched the PubMed database and summarized information on PARP inhibitors, the interaction of PARP-1 with DNA, and the relationships between PARP-1 and p53/ROS, NF-κB/DNA-PK, and caspase3/AIF, respectively. Results: The enzyme PARP-1 plays a crucial role in repairing DNA damage and modifying proteins. Cells exposed to radiation can experience DNA damage, such as single-, intra-, or inter-strand damage. This damage, associated with replication fork stagnation, triggers DNA repair mechanisms, including those involving PARP-1. The activity of PARP-1 increases 500-fold on DNA binding. Studies on PARP-1-knockdown mice have shown that the protein regulates the response to radiation. A lack of PARP-1 also increases the organism's sensitivity to radiation injury. PARP-1 has been found positively or negatively regulate the expression of specific genes through its modulation of key transcription factors and other molecules, including NF-κB, p53, Caspase 3, reactive oxygen species (ROS), and apoptosis-inducing factor (AIF). Conclusion: This review provides a comprehensive analysis of the physiological and pathological roles of PARP-1 and examines the impact of PARP-1 inhibitors under conditions of ionizing radiation exposure. The review also emphasizes the challenges and opportunities for developing PARP-1 inhibitors to improve the clinical outcomes of ionizing radiation damage.

Lestaurtinib induces DNA damage that is related to estrogen receptor activation

A number of chemicals in the environment pose a threat to human health. Recent studies indicate estradiol induces DNA damage through the activation of the estrogen receptor alpha (ERα). Given that many environmental chemical compounds act like hormones once they enter the human body, it is possible that they induce DNA damage in the same way as estradiol, which is of great concern to females with the BRCA1 mutation. In this study, we developed an antibody-based high content method measuring γH2AX, a biomarker for DNA damage, to test a subset of 907 chemical compounds in MCF7 cells. The assay was optimized for a 1536 well plate format and had a satisfactory assay performance with Z-factor of 0.67. From the screening, we identified 128 compounds that induce γH2AX expression in the cells. These compounds were further examined for their γH2AX induction in the presence of an ER inhibitor, tamoxifen. After tamoxifen treatment, four compounds induced less γH2AX expression compared to those without tamoxifen treatment, suggesting these compounds induced γH2AX that is related to ERα activation. These four compounds were chosen for further studies to assess their ERα activating capability and c-MYC induction. Only lestaurtinib, a selective tyrosine kinase inhibitor, induced ERα activation, which was confirmed by both ERα beta-lactamase reporter gene assay and molecular docking analysis. Lestaurtinib also increased c-MYC expression, a target gene of ERα signaling, measured by the quantitative PCR method. This data suggests that lestaurtinib acts as a DNA damage inducer that is related to ERα activation.

Towards Drug Repurposing in Cancer Cachexia: Potential Targets and Candidates

As a multifactorial and multiorgan syndrome, cancer cachexia is associated with decreased tolerance to antitumor treatments and increased morbidity and mortality rates. The current approaches for the treatment of this syndrome are not always effective and well established. Drug repurposing or repositioning consists of the investigation of pharmacological components that are already available or in clinical trials for certain diseases and explores if they can be used for new indications. Its advantages comparing to de novo drugs development are the reduced amount of time spent and costs. In this paper, we selected drugs already available or in clinical trials for non-cachexia indications and that are related to the pathways and molecular components involved in the different phenotypes of cancer cachexia syndrome. Thus, we introduce known drugs as possible candidates for drug repurposing in the treatment of cancer-induced cachexia.

Sp1 Targeted PARP1 Inhibition Protects Cardiomyocytes From Myocardial Ischemia-Reperfusion Injury via Downregulation of Autophagy

Myocardial ischemia–reperfusion injury (MIRI), characterized by post-ischemic cardiomyocytes death and reperfusion myocardial damage, is a lethal yet unresolved complication in the treatment of acute myocardial infarction (AMI). Previous studies have demonstrated that poly(ADP-ribose) polymerase-1 (PARP1) participates in the progression of various cardiovascular diseases, and various reports have proved that PARP1 can be a therapeutic target in these diseases, but whether it plays a role in MIRI is still unknown. Therefore, in this study, we aimed to explore the role and mechanism of PARP1 in the development of MIRI. Firstly, we demonstrated that PARP1 was activated during MIRI-induced myocardial autophagy in vitro. Moreover, PARP1 inhibition protected cardiomyocytes from MIRI through the inhibition of autophagy. Next, we discovered that specificity protein1 (Sp1), as a transcription factor of PARP1, regulates its target gene PARP1 through binding to its target gene promoter during transcription. Furthermore, silencing Sp1 protected cardiomyocytes from MIRI via the inhibition of PARP1. Finally, the functions and mechanisms of PARP1 in the development of MIRI were also verified in vivo with SD rats model. Based on these findings, we concluded that PARP1 inhibition protects cardiomyocytes from MIRI through the inhibition of autophagy, which is targeted by Sp1 suppression. Therefore, the utilization of PARP1 exhibits great therapeutic potential for MIRI treatment in future.

DNA Repair Pathways in Cancer Therapy and Resistance

DNA repair pathways are triggered to maintain genetic stability and integrity when mammalian cells are exposed to endogenous or exogenous DNA-damaging agents. The deregulation of DNA repair pathways is associated with the initiation and progression of cancer. As the primary anti-cancer therapies, ionizing radiation and chemotherapeutic agents induce cell death by directly or indirectly causing DNA damage, dysregulation of the DNA damage response may contribute to hypersensitivity or resistance of cancer cells to genotoxic agents and targeting DNA repair pathway can increase the tumor sensitivity to cancer therapies. Therefore, targeting DNA repair pathways may be a potential therapeutic approach for cancer treatment. A better understanding of the biology and the regulatory mechanisms of DNA repair pathways has the potential to facilitate the development of inhibitors of nuclear and mitochondria DNA repair pathways for enhancing anticancer effect of DNA damage-based therapy.

Class I histone deacetylase inhibition is synthetic lethal with BRCA1 deficiency in breast cancer cells

Breast cancer susceptibility gene 1 (BRCA1) is a tumor suppressor gene, which is frequently mutated in breast and ovarian cancers. BRCA1 plays a key role in the homologous recombination directed DNA repair, allowing its deficiency to act as a therapeutic target of DNA damaging agents. In this study, we found that inhibition of the class I histone deacetylases (HDAC) exhibited synthetic lethality with BRCA1 deficiency in breast cancer cells. Transcriptome profiling and validation study showed that HDAC inhibition enhanced the expression of thioredoxin interaction protein (TXNIP), causing reactive oxygen species (ROS)-mediated DNA damage. This effect induced preferential apoptosis in BRCA1 ^-/- breast cancer cells where DNA repair system is compromised. Two animal experiments and gene expression-associated patients' survival analysis further confirmed in vivo synthetic lethality between BRCA1 and HDAC. Finally, the combination of inhibitors of HDAC and bromodomain and extra-terminal motif (BET), another BRCA1 synthetic lethality target that also works through oxidative stress-mediated DNA damage, showed a strong anticancer effect in BRCA1 ^-/- breast cancer cells. Together, this study provides a new therapeutic strategy for BRCA1-deficient breast cancer by targeting two epigenetic machineries, HDAC and BET.

BRCA1 represses DNA replication initiation through antagonizing estrogen signaling and maintains genome stability in parallel with WEE1-MCM2 signaling during pregnancy

The mammary gland undergoes fast cell proliferation during early pregnancy, yet the mechanism to ensure genome integrity during this highly proliferative stage is largely unknown. We show that pregnancy triggers replicative stresses leading to genetic instability in mice carrying a mammary specific disruption of breast cancer associated gene-1 (BRCA1). The fast cell proliferation was correlated with enhanced expression of most genes encoding replisomes, which are positively regulated by estrogen/ERα signaling but negatively regulated by BRCA1. Our further analysis revealed two parallel signaling pathways, which are mediated by ATR-CHK1 and WEE1-MCM2 and are responsible for regulating DNA replication checkpoint. Upon DNA damage, BRCA1 deficiency markedly enhances DNA replication initiation and preferably impairs DNA replication checkpoint mediated by ATR and CHK1. Meanwhile, DNA damage also activates WEE1-MCM2 signaling, which inhibits DNA replication initiation and enables BRCA1-deficient cells to avoid further genomic instability. Finally, we demonstrated that overriding this defense by WEE1 inhibition in combination with cisplatin, which causes DNA damage, serves as a promising therapeutic approach for killing BRCA1-deficient cancer cells.

The NCATS Pharmaceutical Collection: a 10-year update

The National Center for Advancing Translational Sciences (NCATS) Pharmaceutical Collection (NPC), a comprehensive collection of clinically approved drugs, was made a public resource in 2011. Over the past decade, the NPC has been systematically profiled for activity across an array of pathways and disease models, generating an unparalleled amount of data. These data have not only enabled the identification of new repurposing candidates with several in clinical trials, but also uncovered new biological insights into drug targets and disease mechanisms. This retrospective provides an update on the NPC in terms of both successes and lessons learned. We also report our efforts in bringing the NPC up-to-date with drugs approved in recent years.

Lestaurtinib is a potent inhibitor of anaplastic thyroid cancer cell line models

Anaplastic thyroid cancer (ATC) is a rare and lethal human malignancy with no known effective therapies in the majority of cases. Despite the use of conventional treatments such as chemotherapy, radiation and surgical resection, this disease remains almost universally fatal. In the present study, we identified the JAK2 inhibitor Lestaurtinib as a potent compound when testing against 13 ATC cell lines. Lestaurtinib demonstrated a potent antiproliferative effect in vitro at nanomolar concentrations. Furthermore, Lestaurtinib impeded cell migration and the ability to form colonies from single cells using scratch-wound and colony formation assays, respectively. Flow cytometry was used for cell cycle analysis following drug treatment and demonstrated arrest at the G2/M phase of the cell cycle, indicative of a cytostatic effect. In vivo studies using the chick chorioallantoic membrane xenograft models demonstrated that treatment with Lestaurtinib resulted in a significant decrease in endpoint tumor volume and vascularity using power Doppler ultrasound imaging. Overall, this study provides evidence that Lestaurtinib is a potent antiproliferative agent with potential antiangiogenic activity that warrants further investigation as a targeted therapy for ATC.

BRCA1 deficiency sensitizes breast cancer cells to bromodomain and extra-terminal domain (BET) inhibition

BRCA1 is a tumor suppressor frequently mutated in breast and ovarian cancer, serving it as a target for therapeutic exploitation. Here, we show that BRCA1 has a synthetic lethality interaction with an epigenetics regulator, bromodomain and extra-terminal domain (BET). BET inhibition led to gene expression changes reversing MYC-dependent transcription repression of a redox regulator, thioredoxin-interacting protein (TXNIP), via switching the promoter occupant from MYC to MondoA:MLX complex. Reversing the MYC-TXNIP axis inhibited thioredoxin activity and elevated cellular oxidative stress, causing DNA damages that are detrimental to BRCA1-deficient breast cancer cells. Tumor xenograft models and breast cancer clinical data analyses further demonstrated an in vivo synthetic lethality interaction and clinical association between BET/TXNIP and BRCA1 deficiency in the survival of breast cancer patients.

Bioactive Indolocarbazoles from the Marine-Derived Streptomyces sp. DT-A61

Nine new indolocarbazoles (1-9) were isolated from the marine-derived Streptomyces sp. DT-A61. Among them compounds 1-8 featured a hydroxy group at the C-3 or C-9 position. All purified compounds were identified by 1D and 2D NMR and HRESIMS data. The absolute configurations of 4-6, 8, and 9 were determined by electronic circular dichroism spectroscopic data. Compound 7 exhibited significant activity against human prostate PC-3 cancer cells with an IC₅₀ value of 0.16 μM. Compounds 1, 5, 6, and 9 showed moderate inhibition against the same cell line with IC₅₀ values of 8.0, 3.6, 3.1, and 5.6 μM. Compound 2 displayed a notable inhibitory effect against Rho-associated protein kinase (ROCK2) with an IC₅₀ value of 5.7 nM, which was similar to the positive control staurosporine (IC₅₀ 7.8 nM).

Investigating the mechanism of hepatocellular carcinoma progression by constructing genetic and epigenetic networks using NGS data identification and big database mining method

The mechanisms leading to the development and progression of hepatocellular carcinoma (HCC) are complicated and regulated genetically and epigenetically. The recent advancement in high-throughput sequencing has facilitated investigations into the role of genetic and epigenetic regulations in hepatocarcinogenesis. Therefore, we used systems biology and big database mining to construct genetic and epigenetic networks (GENs) using the information about mRNA, miRNA, and methylation profiles of HCC patients. Our approach involves analyzing gene regulatory networks (GRNs), protein-protein networks (PPINs), and epigenetic networks at different stages of hepatocarcinogenesis. The core GENs, influencing each stage of HCC, were extracted via principal network projection (PNP). The pathways during different stages of HCC were compared. We observed that extracellular signals were further transduced to transcription factors (TFs), resulting in the aberrant regulation of their target genes, in turn inducing mechanisms that are responsible for HCC progression, including cell proliferation, anti-apoptosis, aberrant cell cycle, cell survival, and metastasis. We also selected potential multiple drugs specific to prominent epigenetic network markers of each stage of HCC: lestaurtinib, dinaciclib, and perifosine against the NTRK2, MYC, and AKT1 markers influencing HCC progression from stage I to stage II; celecoxib, axitinib, and vinblastine against the DDIT3, PDGFB, and JUN markers influencing HCC progression from stage II to stage III; and atiprimod, celastrol, and bortezomib against STAT3, IL1B, and NFKB1 markers influencing HCC progression from stage III to stage IV.

WEE1 inhibition targets cell cycle checkpoints for triple negative breast cancers to overcome cisplatin resistance

Cisplatin is one of the most commonly used therapeutic drugs for cancer therapy, yet prolonged cisplatin treatment frequently results in drug resistance. To enhance therapeutic effect of cisplatin, we conducted a high throughput screening using a kinase library containing 704 kinases against triple negative breast cancer (TNBC) cells. We demonstrated that cisplatin activates ATR, CHK1 and WEE1, which shut down DNA replication and attenuate cisplatin induced-lethality. WEE1 inhibition sensitizes TNBCs and cisplatin resistant cancer cells to cisplatin-induced lethality, because it not only impairs DNA replication checkpoint more profoundly than inhibition of ATR or CHK1, but also defects G2-M cell cycle checkpoint. Finally, we demonstrated that combined cisplatin treatment and WEE1 inhibition synergistically inhibits xenograft cancer growth accompanied by markedly reduced expression of TNBC signature genes. Thus targeting DNA replication and G2-M cell cycle checkpoint simultaneously by cisplatin and WEE1 inhibition is promising for TNBCs treatment, and for overcoming their cisplatin resistance.

Tropomyosin-related kinase B/brain derived-neurotrophic factor signaling pathway as a potential therapeutic target for colorectal cancer

Colorectal cancer (CRC) is the second most common cause of cancer-related death in western countries. Approximately one-quarter of newly diagnosed patients for CRC have metastases, and a further 40%-50% experience disease recurrence or develop metastases after all standard therapies. Therefore, understanding the molecular mechanisms involved in the progression of CRC and subsequently developing novel therapeutic targets is crucial to improve management of CRC and patients’ long-term survival. Several tyrosine kinase receptors have been implicated in CRC development, progression and metastasis, including epidermal growth factor receptor (EGFR) and vascular EGFR. Recently, tropomyosin-related kinase B (TrkB), a tyrosine kinase receptor, has been reported in CRC and found to clearly exert several biological and clinical features, such as tumor cell growth and survival in vitro and in vivo, metastasis formation and poor prognosis. Here we review the significance of TrkB and its ligand brain derived-neurotrophic factor in CRC. We focus on their expression in CRC tumor samples, and their functional roles in CRC cell lines and in in vivo models. Finally we discuss therapeutic approaches that can lead to the development of novel therapeutic agents for treating TrkB-expressing CRC tumors.

Small PARP inhibitor PJ-34 induces cell cycle arrest and apoptosis of adult T-cell leukemia cells

Background

HTLV-I is associated with the development of an aggressive form of lymphocytic leukemia known as adult T-cell leukemia/lymphoma (ATLL). A major obstacle for effective treatment of ATLL resides in the genetic diversity of tumor cells and their ability to acquire resistance to chemotherapy regimens. As a result, most patients relapse and current therapeutic approaches still have limited long-term survival benefits. Hence, the development of novel approaches is greatly needed.

Methods

In this study, we found that a small molecule inhibitor of poly (ADP-ribose) polymerase (PARP), PJ-34, is very effective in activating S/G2M cell cycle checkpoints, resulting in permanent cell cycle arrest and reactivation of p53 transcription functions and caspase-3-dependent apoptosis of HTLV-I-transformed and patient-derived ATLL tumor cells. We also found that HTLV-I-transformed MT-2 cells are resistant to PJ-34 therapy associated with reduced cleaved caspase-3 activation and increased expression of RelA/p65.

Conclusion

Since PJ-34 has been tested in clinical trials for the treatment of solid tumors, our results suggest that some ATLL patients may be good candidates to benefit from PJ-34 therapy.