Molecular mechanisms of etoposide

Computational Microbiome Pharmacology Analysis Elucidates the Anti-Cancer Potential of Vaginal Microbes and Metabolites

The vaginal microbiome's role in risk, progression, and treatment of female cancers has been widely explored. Yet, there remains a need to develop methods to understand the interaction of microbiome factors with host cells and to characterize their potential therapeutic functions. To address this challenge, we developed a systems biology framework we term the Pharmacobiome for microbiome pharmacology analysis. The Pharmacobiome framework evaluates similarities between microbes and microbial byproducts and known drugs based on their impact on host transcriptomic cellular signatures. Here, we apply our framework to characterization of the Anti-Gynecologic Cancer Vaginal Pharmacobiome. Using published vaginal microbiome multi-omics data from the Partners PrEP clinical trial, we constructed vaginal epithelial gene signatures associated with each profiled vaginal microbe and metabolite. We compared these microbiome-associated host gene signatures to post-drug perturbation host gene signatures associated with 35 FDA-approved anti-cancer drugs from the Library of Integrated Network-based Cellular Signatures database to identify vaginal microbes and metabolites with high statistical and functional similarity to these drugs. We found that Lactobacilli and their metabolites can regulate host gene expression in ways similar to many anti-cancer drugs. Additionally, we experimentally tested our model prediction that taurine, a metabolite produced by L. crispatus, kills cancerous breast and endometrial cancer cells. Our study shows that the Pharmacobiome is a powerful framework for characterizing the anti-cancer therapeutic potential of vaginal microbiome factors with generalizability to other cancers, microbiomes, and diseases.

Mapping multimodal phenotypes to perturbations in cells and tissue with CRISPRmap

Unlike sequencing-based methods, which require cell lysis, optical pooled genetic screens enable investigation of spatial phenotypes, including cell morphology, protein subcellular localization, cell-cell interactions and tissue organization, in response to targeted CRISPR perturbations. Here we report a multimodal optical pooled CRISPR screening method, which we call CRISPRmap. CRISPRmap combines in situ CRISPR guide-identifying barcode readout with multiplexed immunofluorescence and RNA detection. Barcodes are detected and read out through combinatorial hybridization of DNA oligos, enhancing barcode detection efficiency. CRISPRmap enables in situ barcode readout in cell types and contexts that were elusive to conventional optical pooled screening, including cultured primary cells, embryonic stem cells, induced pluripotent stem cells, derived neurons and in vivo cells in a tissue context. We conducted a screen in a breast cancer cell line of the effects of DNA damage repair gene variants on cellular responses to commonly used cancer therapies, and we show that optical phenotyping pinpoints likely pathogenic patient-derived mutations that were previously classified as variants of unknown clinical significance.

C-4 analogues of podophyllotoxin as tubulin inhibitors: synthesis, biological evaluation, and structure-activity relationship

The diversity of lignan small molecules derived from podophyllotoxin, a non-covalent tubulin inhibitor isolated from the Podophyllum family, has led to the clinical development of FDA-approved anticancer agents etoposide and teniposide. While these two compounds share the same tetracyclic core as podophyllotoxin, two subtle structural changes-4' demethylation on the aromatic ring and stereospecific glycosylation at the C-4 hydroxyl-result in an alternate biological mechanism. Given the immense pharmacological importance of altering the C-4 position, we synthesised and evaluated a systematic library of diversified esters to establish a structure-activity relationship regarding modification at C-4 on the properties of podophyllotoxin. We determined the biological activity of these esters through cell viability assays, computer docking models, tubulin polymerisation assays, and cell cycle analysis. Altogether, we demonstrate that increasing steric hindrance at C-4 leads to a loss in potency against human cancer cells but has a significantly lesser impact on cell-free tubulin inhibition.

Redox-dependent condensation and cytoplasmic granulation by human ssDNA-binding protein-1 delineate roles in oxidative stress response

Human single-stranded DNA binding protein 1 (hSSB1/NABP2/OBFC2B) plays central roles in DNA repair. Here, we show that purified hSSB1 undergoes redox-dependent liquid-liquid phase separation (LLPS) in the presence of single-stranded DNA or RNA, features that are distinct from those of LLPS by bacterial SSB. hSSB1 nucleoprotein droplets form under physiological ionic conditions in response to treatment modeling cellular oxidative stress. hSSB1's intrinsically disordered region is indispensable for LLPS, whereas all three cysteine residues of the oligonucleotide/oligosaccharide-binding fold are necessary to maintain redox-sensitive droplet formation. Proteins interacting with hSSB1 show selective enrichment inside hSSB1 droplets, suggesting tight content control and recruitment functions for the condensates. While these features appear instrumental for genome repair, we detected cytoplasmic hSSB1 condensates in various cell lines colocalizing with stress granules upon oxidative stress, implying extranuclear function in cellular stress response. Our results suggest condensation-linked roles for hSSB1, linking genome repair and cytoplasmic defense.

Live Cell Painting: image-based profiling in live cells using Acridine Orange

Image-based profiling has been used to analyze cell health, drug mechanism of action, CRISPR-edited cells, and overall cytotoxicity. Cell Painting is a broadly used image-based assay that uses morphological features to capture how cells respond to treatments. However, this method requires cell fixation for staining, which prevents examining live cells. To address this limitation, here we present Live Cell Painting (LCP), a high-content method based on Acridine orange, a metachromatic dye that labels different organelles and cellular structures. We began by showing that LCP can be applied to follow acidic vesicle redistribution of cells exposed to acidic vesicles inhibitors. Next, we show that LCP can identify subtle changes in cells exposed to silver nanoparticles that are not detected by techniques such as MTT assay. In drug treatments, LCP was helpful in assessing the dose-response relationship and creating profiles that allow clustering of drugs that cause liver injury. Here, we present an affordable and easy-to-use image-based assay capable of assessing overall cell health and showing promise for use in various applications such as assessing drugs and nanoparticles. We envisage the use of Live Cell Painting as an initial screening of overall cell health while providing insights into new biological questions.

Targeting drug resistance in glioblastoma (Review)

Glioblastoma (GBM) is the most common malignancy of the central nervous system in adults. The current standard of care includes surgery, radiation therapy, temozolomide; and tumor‑treating fields leads to dismal overall survival. There are far limited treatments upon recurrence. Therapies to date are ineffective as a result of several factors, including the presence of the blood‑brain barrier, blood tumor barrier, glioma stem‑like cells and genetic heterogeneity in GBM. In the present review, the potential mechanisms that lead to treatment resistance in GBM and the measures which have been taken so far to attempt to overcome the resistance were discussed. The complex biology of GBM and lack of comprehensive understanding of the development of therapeutic resistance in GBM demands discovery of novel antigens that are targetable and provide effective therapeutic strategies.

In Vivo and Clinical Studies of Natural Products Targeting the Hallmarks of Cancer

Despite more than 200 approved anticancer agents, cancer remains a leading cause of death worldwide due to disease complexity, tumour heterogeneity, drug toxicity, and the emergence of drug resistance. Accordingly, the development of chemotherapeutic agents with higher efficacy, a better safety profile, and the capability of bypassing drug resistance would be a cornerstone in cancer therapy. Natural products have played a pivotal role in the field of drug discovery, especially for the pharmacotherapy of cancer, infectious, and chronic diseases. Owing to their distinctive structures and multiple mechanistic activities, natural products and their derivatives have been utilized for decades in cancer treatment protocols. In this review, we delve into the potential of natural products as anticancer agents by targeting cancer's hallmarks, including sustained proliferative signalling, evading growth suppression, resisting apoptosis and cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. We highlight the molecular mechanisms of some natural products, in vivo studies, and promising clinical trials. This review emphasizes the significance of natural products in fighting cancer and the need for further studies to uncover their fully therapeutic potential.

Emerging role of MYB transcription factors in cancer drug resistance

Decades ago, the viral myeloblastosis oncogene v-myb was identified as a gene responsible for the development of avian leukemia. However, the relevance of MYB proteins for human cancer diseases, in particular for solid tumors, remained basically unrecognized for a very long time. The human family of MYB transcription factors comprises MYB (c-MYB), MYBL2 (b-MYB), and MYBL1 (a-MYB), which are overexpressed in several cancers and are associated with cancer progression and resistance to anticancer drugs. In addition to overexpression, the presence of activated MYB-fusion proteins as tumor drivers was described in certain cancers. The identification of anticancer drug resistance mediated by MYB proteins and their underlying mechanisms are of great importance in understanding failures of current therapies and establishing new and more efficient therapy regimens. In addition, new drug candidates targeting MYB transcription factor activity and signaling have emerged as a promising class of potential anticancer therapeutics that could tackle MYB-dependent drug-resistant cancers in a more selective way. This review describes the correlation of MYB transcription factors with the formation and persistence of cancer resistance to various approved and investigational anticancer drugs.

CDK9-55 guides the anaphase-promoting complex/cyclosome (APC/C) in choosing the DNA repair pathway choice

DNA double-strand breaks (DSBs) contribute to genome instability, a key feature of cancer. DSBs are mainly repaired by homologous recombination (HR) and non-homologous end-joining (NHEJ). We investigated the role of an isoform of the multifunctional cyclin-dependent kinase 9, CDK9-55, in DNA repair, by generating CDK9-55-knockout HeLa clones (through CRISPR-Cas9), which showed potential HR dysfunction. A phosphoproteomic screening in these clones treated with camptothecin revealed that CDC23 (cell division cycle 23), a component of the E3-ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome), is a new substrate of CDK9-55, with S588 being its putative phosphorylation site. Mutated non-phosphorylatable CDC23(S588A) affected the repair pathway choice by impairing HR and favouring error-prone NHEJ. This CDK9 role should be considered when designing CDK-inhibitor-based cancer therapies.

Leukemogenesis occurs in a microenvironment enriched by extracellular microvesicles/exosomes: recent discoveries and questions to be answered

In single-cell organisms, extracellular microvesicles (ExMVs) were one of the first cell-cell communication platforms that emerged very early during evolution. Multicellular organisms subsequently adapted this mechanism. Evidence indicates that all types of cells secrete these small circular structures surrounded by a lipid membrane that may be encrusted by ligands and receptors interacting with target cells and harboring inside a cargo comprising RNA species, proteins, bioactive lipids, signaling nucleotides, and even entire organelles "hijacked" from the cells of origin. ExMVs are secreted by normal cells and at higher levels by malignant cells, and there are some differences in their cargo. On the one hand, ExMVs secreted from malignant cells interact with cells in the microenvironment, and in return, they are exposed by a "two-way mechanism" to ExMVs secreted by non-leukemic cells. Therefore, leukemogenesis occurs and progresses in ExMVs enriched microenvironments, and this biological fact has pathologic, diagnostic, and therapeutic implications. We are still trying to decipher this intriguing cell-cell communication language better. We will present a current point of view on this topic and review some selected most recent discoveries and papers.

Engineered Artesunate-Naphthalimide Hybrid Dual Drug for Synergistic Multimodal Therapy against Experimental Murine Lymphoma

Lymphoma can effectively be treated with a chemotherapy regimen that is associated with adverse side effects due to increasing drug resistance, so there is an emergent need for alternative small-molecule inhibitors to overcome the resistance that occurs in lymphoma management and overall increase the prognosis rate. A new series of substituted naphthalimide moieties conjugated via ester and amide linkages with artesunate were designed, synthesized, and characterized. In addition to the conjugates, to further achieve a theranostic molecule, FITC was incorporated via a multistep synthesis process. DNA binding studies of these selected derivatives by ultraviolet-visible (UV-vis), fluorescence spectroscopy, intercalating dye (EtBr, acridine orange)-DNA competitive assay, and minor groove binding dye Hoechst 33342-DNA competitive assay suggested that the synthesized novel molecules intercalated between the two strands of DNA due to its naphthalimide moiety and its counterpart artesunate binds with the minor groove of DNA. Napthalimide-artesunate conjugates inhibit the growth of lymphoma and induce apoptosis, including ready incorporation and reduction in cell viability. The remodeled drug has a significant tumoricidal effect against solid DL tumors developed in BALB/c mice in a dose-dependent manner. The novel drug appears to inhibit metastasis and increase the survival of the treated animals compared with untreated littermates.

Liver Dysfunction in Adult Hemophagocytic Lymphohistiocytosis: A Narrative Review

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition that has been increasingly recognized in adults and is characterized by a hyperinflammatory state due to immune dysregulation. Its nonspecific presentation, the lack of clinician familiarity given its rarity, and shared clinical features with sepsis and other syndromes can lead to a delay in diagnosis and a poor prognosis. Significant liver function abnormalities as the initial manifestation of HLH are uncommon and can range from mild elevation of aminotransferases to fulminant hepatic failure with high mortality rates. The authors encountered a case of adult HLH mimicking acute viral hepatitis in which a markedly elevated ferritin level led to a prompt diagnosis, early initiation of treatment, and a successful outcome. Clinicians, including gastroenterologists and hepatologists, are often called upon to evaluate patients with abnormal liver tests and may lack experience in the early diagnosis and management of liver dysfunction in the context of HLH. Thus, we expand our reporting to a narrative review of literature which explores the pathogenesis of HLH, challenges associated with its diagnosis, previous reports of liver disease associated with the syndrome, recommended treatments for the familial and adult variations including the role of liver transplantation, and the outcomes of these treatments.

Association between chemotherapy-induced myelosuppression and curative efficacy of 2-cycle chemotherapy in small cell lung cancer

BACKGROUND

The association of chemotherapy-induced myelosuppression with tumor response and overall survival remained controversial. The study was conducted to investigate the association between them in small cell lung cancer (SCLC).

METHODS

204 eligible patients with SCLC were respectively included and categorized into three groups (no, mild, and severe myelosuppression) based on myelosuppression degree after the first chemotherapy. Curative efficacy of 2-cycle chemotherapy was evaluated by the objective response rate (ORR) and disease control rate (DCR). Univariate and multivariate logistic regression analyses were conducted to investigate their association. Receiver operator characteristic (ROC) curves, net reclassification index (NRI), and integrated discrimination improvement (IDI) were used to assess the predictive ability of myelosuppression.

RESULTS

In the fully-adjusted model, mild (OR, 4.61; 95% CI, 1.35 to 18.27; P = 0.020) and severe (OR, 7.22; 95% CI, 1.30 to 72.44; P = 0.046) myelosuppression were positively associated with DCR. However, only mild myelosuppression was significantly associated with ORR (OR, 2.78; 95% CI, 1.30 to 6.14; P = 0.010). Although we observed evidence of increased ORR in severe myelosuppression, the difference was not statistically significant. Furthermore, based on the results of the ROC curve, NRI and IDI, chemotherapy-induced myelosuppression cannot be used as a accurate and independent predictor for curative efficacy, but it can improve overall prediction accuracy.

CONCLUSION

Chemotherapy-induced myelosuppression was significantly associated with curative efficacy of 2-cycle chemotherapy in SCLC, which could help predict treatment efficacy and guide chemotherapy dosage.

CRISPR/Cas9 mediated Y-chromosome elimination affects human cells transcriptome

BACKGROUND

Sexual dimorphism represents a key concept in the comprehension of molecular processes guiding several sex-specific physiological and pathological mechanisms. It has been reported that genes involved in many disorders show a sex-dependent expression pattern. Moreover, the loss of Y chromosome (LOY), found to be a physiological age-driven phenomenon, has been linked to many neurodegenerative and autoimmune disorders, and to an increased cancer risk. These findings drove us towards the consideration that LOY may cause the de-regulation of disease specific networks, involving genes located in both autosomal and sex chromosomes.

RESULTS

Exploiting the CRISPR/Cas9 and RNA-sequencing technologies, we generated a Y-deficient human cell line that has been investigated for its gene expression profile. Our results showed that LOY can influence the transcriptome displaying relevant enriched biological processes, such as cell migration regulation, angiogenesis and immune response. Interestingly, the ovarian follicle development pathway was found enriched, supporting the female-mimicking profile of male Y-depleted cells.

CONCLUSION

This study, besides proposing a novel approach to investigate sex-biased physiological and pathological conditions, highlights new roles for the Y chromosome in the sexual dimorphism characterizing human health and diseases. Moreover, this analysis paves the way for the research of new therapeutic approaches for sex dimorphic and LOY-related diseases.

Microarray data analysis of antileukemic action of Cinnamoylated benzaldehyde LQB-461 in Jurkat cell line

BACKGROUND

Leukemias stand out for being the main type of childhood cancer in the world. Current treatments have strong side effects for patients, and there is still a high rate of development of resistance to multidrug therapy. Previously, our research group developed a structure-activity study with novel synthetic molecules analogous to LQB-278, described as an essential molecule with in vitro antileukemic action. Among these analogs, LQB-461 stood out, presenting more significant antileukemic action compared to its derivative LQB-278, with cytostatic and cytotoxicity effect by apoptosis, inducing caspase-3, and increased sub-G1 phase on cell cycle analysis.

METHODS AND RESULTS

Deepening the study of the mechanism of action of LQB-461 in Jurkat cells in vitro, a microarray assay was carried out, which confirmed the importance of the apoptosis pathway in the LQB-461 activity. Through real-time PCR, we validated an increased expression of CDKN1A and BAX genes, essential mediators of the apoptosis intrinsic pathway. Through the extrinsic apoptosis pathway, we found an increased expression of the Fas receptor by flow cytometry, showing the presence of a more sensitive population and another more resistant to death. Considering the importance of autophagy in cellular resistance, it was demonstrated by western blotting that LQB-461 decreased LC-3 protein expression, an autophagic marker.

CONCLUSIONS

These results suggest that this synthetic molecule LQB-461 induces cell death by apoptosis in Jurkat cells through intrinsic and extrinsic pathways and inhibits autophagy, overcoming some mechanisms of cell resistance related to this process, which differentiates LQB-461 of other drugs used for the leukemia treatment.

PSIP1/LEDGF reduces R-loops at transcription sites to maintain genome integrity

R-loops that accumulate at transcription sites pose a persistent threat to genome integrity. PSIP1 is a chromatin protein associated with transcriptional elongation complex, possesses histone chaperone activity, and is implicated in recruiting RNA processing and DNA repair factors to transcription sites. Here, we show that PSIP1 interacts with R-loops and other proteins involved in R-loop homeostasis, including PARP1. Genome-wide mapping of PSIP1, R-loops and γ-H2AX in PSIP1-depleted human and mouse cell lines revealed an accumulation of R-loops and DNA damage at gene promoters in the absence of PSIP1. R-loop accumulation causes local transcriptional arrest and transcription-replication conflict, leading to DNA damage. PSIP1 depletion increases 53BP1 foci and reduces RAD51 foci, suggesting altered DNA repair choice. Furthermore, PSIP1 depletion increases the sensitivity of cancer cells to PARP1 inhibitors and DNA-damaging agents that induce R-loop-induced DNA damage. These findings provide insights into the mechanism through which PSIP1 maintains genome integrity at the site of transcription.

Polarity-Driven Two-Photon Fluorescent Probe for Monitoring the Perturbation in Lipid Droplet Levels during Mitochondrial Dysfunction and Acute Pancreatitis

Lipid droplets (LDs) act as an energy reservoir in cancer cells; on the other hand, mitochondria are hyperactive to fulfill the energy demand to accelerate cell proliferation. We are interested in unfolding the relationship between the cellular energy reservoir and energy producer through fluorescence labeling. Thus, a dual organelle-targeted fluorescent probe MLD-1 has been rationally developed. It visualized the crosstalk between mitochondrial dysfunction and the fluctuation of LDs in live cells. Its two-photon ability allowed us to acquire deep tissue images. For the first time, we have shown that the probe has the ability to track the accumulation of LDs in different mouse organs during pancreatic inflammation. MLD-1, being a selectively polarity-driven, chemo- and photostable LD probe, may offer great possibilities for studying LD-associated biology in due course.

Non-chemotherapy adjuvant agents in TP53 mutant Ewing sarcoma

Ewing sarcoma (EWS) is a malignant tumor arising in bone or soft tissue that occurs in adolescent and young adult patients as well as adults later in life. Although non-metastatic EWS is typically responsive to treatment when newly diagnosed, relapsed cases have an unmet need for which no standard treatment approach exists. Recent phase III clinical trials for EWS comparing 7 vs 5 chemotherapy drugs have failed to improve survival. To extend the durability of remission for EWS, we investigated 3 non-chemotherapy adjuvant therapy drug candidates to be combined with chemotherapy. The efficacy of these adjuvant drugs was investigated via anchorage-dependent growth assays, anchorage-independent soft-agar colony formation assays and EWS xenograft mouse models. Enoxacin and entinostat were the most effective adjuvant drug in both long-term in vitro and in vivo adjuvant studies. In the context that enoxacin is an FDA-approved antibiotic, and that entinostat is an investigational agent not yet FDA-approved, we propose enoxacin as an adjuvant drug for further preclinical and clinical investigation in EWS patients.

Revisiting treatment-related cardiotoxicity in patients with malignant lymphoma-a review and prospects for the future

Treatment of malignant lymphoma has for years been represented by many cardiotoxic agents especially anthracyclines, cyclophosphamide, and thoracic irradiation. Although they are in clinical practice for decades, the precise mechanism of cardiotoxicity and effective prevention is still part of the research. At this article we discuss most routinely used anti-cancer drugs in chemotherapeutic regiments for malignant lymphoma with the focus on novel insight on molecular mechanisms of cardiotoxicity. Understanding toxicity at molecular levels may unveil possible targets of cardioprotective supportive therapy or optimization of current therapeutic protocols. Additionally, we review novel specific targeted therapy and its challenges in cardio-oncology.

Exploration of potential molecular mechanisms and genotoxicity of anti-cancer drugs using next generation knowledge discovery methods

Background & Objectives

Accurate identification of molecular and toxicological functions of potential drug candidates is crucial for drug discovery and development. This may aid in the evaluation of the risks of genotoxicity and carcinogenesis. In addition, in silico characterization of existing and new drugs might offer clues for future investigations and aid in the development of anticancer treatments. Using next-generation knowledge discovery (NGKD) methodology, we endeavored to establish a risk assessment of anticancer drugs for their molecular mechanism(s) and genotoxicity.

Methods

This study was performed at the Faculty of Applied Medical Sciences, King Abdulaziz University (KAU), Jeddah, Saudi Arabia, in November 2022. Using innovative in silico model systems, we assessed the molecular mechanism of action and toxicity of around 20 distinct substances such as Deguelin, Etoposide, Camptothecin, Cytarabine (Ara-C), Cisplatin, Hydroxyurea, Trichostain A, Antimycin, Colchicine, 2-deoxyglucose, Tunicamycin, Thapsigargin, Vinblastin, Docetaxel, Oxaliplatin, Methotrexate, 5-flurouracil, Bleomycin, Taxol (Paclitaxel), and Apicidin. Using the Ingenuity Pathway Analysis (IPA) knowledge base, the number of targets for each compound was determined in silico. Subsequently, they were examined using Fisher's exact test and Benjamini Hochberg Multiple Testing Correction (P<0.05) and submitted to core analysis with IPA to decode the biological and toxicological activities differently controlled by these drugs. In addition, a multiple comparison module in IPA was used to compare the core analyses of each molecule. In addition, we obtained the top 100 protein targets of Etoposide, Camptothecin, and Ara-C using SwissTargetPrediction, as well as the key pathways and gene ontologies affected by these drugs and disease associations using the WebGestalt tool.

Results

We identified distinct toxicological signatures and canonical signaling pathways in tumor cell lines regulated by these 20 anticancer drugs. These signaling pathways included cell death and apoptosis in addition to molecular processes, p53 signaling, and aryl hydrocarbon receptor signaling. The TP53 signaling pathway is utilized by these agents to effectively trigger cell death and apoptosis, and p53 functions as a master regulator in a variety of cellular stress responses, including genotoxic stress.

Conclusion

Our research has laid the groundwork for the discovery of additional biomarkers that assess both the safety and effectiveness of treatment. Our mechanism based "NGKD" tools have more relevance for the identification of safer therapies and has the potential to lead to the rational screening of drug candidates targeting specific molecular networks and canonical pathways implicated in cancer and genotoxicity. In addition, the combination of protein, microRNA and metabolome profiles may be essential for the development of translatable biomarkers for the safety and efficacy of pharmacotherapeutic agents.Our research has laid the groundwork for the discovery of additional biomarkers that assess both the safety and the effectiveness of a treatment.

Combinatorial drug screening on 3D Ewing sarcoma spheroids using droplet-based microfluidics

Culturing and screening cells in microfluidics, particularly in three-dimensional formats, has the potential to impact diverse areas from fundamental biology to cancer precision medicine. Here, we use a platform based on anchored droplets for drug screening. The response of spheroids of Ewing sarcoma (EwS) A673 cells to simultaneous or sequential combinations of etoposide and cisplatin was evaluated. This was done by culturing spheroids of EwS cells inside 500 nL droplets then merging them with secondary droplets containing fluorescent-barcoded drugs at different concentrations. Differences in EwS spheroid growth and viability were measured by microscopy. After drug exposure such measurements enabled estimation of their IC50 values, which were in agreement with values obtained in standard multiwell plates. Then, synergistic drug combination was evaluated. Sequential combination treatment of EwS with etoposide applied 24 h before cisplatin resulted in amplified synergistic effect. As such, droplet-based microfluidics offers the modularity required for evaluation of drug combinations.

Effect of metformin alone and in combination with etoposide and epirubicin on proliferation, apoptosis, necrosis, and migration of B-CPAP and SW cells as thyroid cancer cell lines

Background and purpose

There has not been a comprehensive study on the simultaneous effects of metformin, etoposide, and epirubicin on thyroid cancer cells. Hence, the current research proposed the in vitro study on the effect of metformin alone and in combination with etoposide and epirubicin on the rate of proliferation, apoptosis, necrosis, and migration against B-CPAP and SW-1736 cells as thyroid cancer cell lines.

Experimental approach

MTT-based proliferation assay, combination index method, flow cytometry, and scratch wound healing assays were used to evaluate the simultaneous effects of the three approved drugs against thyroid cancer cells.

Findings/Results

This study showed that the toxic concentration of metformin on normal Hu02 cells was more than 10 folds higher than B-CPAP and SW cancerous cells. Metformin in combination with epirubicin and etoposide could increase percentages of B-CPAP and SW cells in early and late apoptosis and necrosis phases in comparison with their single concentrations, significantly. Metformin in combination with epirubicin and etoposide could arrest the S phase in B-CPAP and SW cells, significantly. Metformin in combination with epirubicin and etoposide could reduce ~100% migration rate, whereas single concentrations of epirubicin and etoposide could reduce ~50% migration rate.

Conclusion and implication

Combined treatment of metformin with anticancer drugs epirubicin and etoposide can increase the mortality in thyroid cancer cell lines and reduce the toxicity of these drugs on the normal cell line, which could be the starting point for proposing a new combination strategy in the therapy of thyroid cancer to induce more potency and reduce acute toxicity.

Sex specific regulation of TSPY-Like 2 in the DNA damage response of cancer cells

Females have a lower probability to develop somatic cancers and a better response to chemotherapy than males. However, the reasons for these differences are still not well understood. The X-linked gene TSPY-Like 2 (TSPYL2) encodes for a putative tumor suppressor protein involved in cell cycle regulation and DNA damage response (DDR) pathways. Here, we demonstrate that in unstressed conditions TSPYL2 is maintained at low levels by MDM2-dependent ubiquitination and proteasome degradation. Upon genotoxic stress, E2F1 promotes TSPYL2 expression and protein accumulation in non-transformed cell lines. Conversely, in cancer cells, TSPYL2 accumulates only in females or in those male cancer cells that lost the Y-chromosome during the oncogenic process. Hence, we demonstrate that while TSPYL2 mRNA is induced in all the tested tumor cell lines after DNA damage, TSPYL2 protein stability is increased only in female cancer cells. Indeed, we found that TSPYL2 accumulation, in male cancer cells, is prevented by the Y-encoded protein SRY, which modulates MDM2 protein levels. In addition, we demonstrated that TSPYL2 accumulation is required to sustain cell growth arrest after DNA damage, possibly contributing to protect normal and female cancer cells from tumor progression. Accordingly, TSPYL2 has been found more frequently mutated in female-specific cancers. These findings demonstrate for the first time a sex-specific regulation of TSPYL2 in the DDR of cancer cells and confirm the existence of sexual dimorphism in DNA surveillance pathways.

The protective effect of taurine, piracetam and vinpocetine on etoposide-induced inflammation and brain injury in the serum of female albino rats

Etoposide (ETP) is one of the leading antitumour agents in cancer chemotherapy. Many studies have reported on ETP-induced peripheral neuropathy; however, few reports have focused on its brain toxicity. The current research investigates the protective potential of taurine, piracetam and vinpocetine on serum biomarkers associated with inflammation and brain injury induced by ETP in a rodent model. A total of 30 female albino rats were equally divided into five groups; the 1^st and 2^nd groups were the control and ETP-treated groups, respectively, while the 3^rd, 4^th and 5^th groups were ETP-treated rats cotreated with taurine, piracetam and vinpocetine, respectively. Administration of ETP reduced body weight significantly, enhanced production of serum proinflammatory cytokines including tumour necrosis factor-alpha, interleukin-1 beta (IL-1β) and IL-6 and decreased glutathione serum levels. Moreover, ETP treatment resulted in upregulation of glial fibrillary acidic protein expression and histopathological alterations in the rats' brain compared to the control group. Co-treatment with taurine, piracetam and vinpocetine counteracted ETP-induced brain injury and altered serum biomarkers levels. We concluded that co-treatment with vinpocetine could serve as a complementary therapeutic agent in reducing brain injury and toxicity induced by ETP.

Application of a new approach methodology (NAM)-based strategy for genotoxicity assessment of data-poor compounds

The conventional battery for genotoxicity testing is not well suited to assessing the large number of chemicals needing evaluation. Traditional in vitro tests lack throughput, provide little mechanistic information, and have poor specificity in predicting in vivo genotoxicity. New Approach Methodologies (NAMs) aim to accelerate the pace of hazard assessment and reduce reliance on in vivo tests that are time-consuming and resource-intensive. As such, high-throughput transcriptomic and flow cytometry-based assays have been developed for modernized in vitro genotoxicity assessment. This includes: the TGx-DDI transcriptomic biomarker (i.e., 64-gene expression signature to identify DNA damage-inducing (DDI) substances), the MicroFlow^® assay (i.e., a flow cytometry-based micronucleus (MN) test), and the MultiFlow^® assay (i.e., a multiplexed flow cytometry-based reporter assay that yields mode of action (MoA) information). The objective of this study was to investigate the utility of the TGx-DDI transcriptomic biomarker, multiplexed with the MicroFlow^® and MultiFlow^® assays, as an integrated NAM-based testing strategy for screening data-poor compounds prioritized by Health Canada's New Substances Assessment and Control Bureau. Human lymphoblastoid TK6 cells were exposed to 3 control and 10 data-poor substances, using a 6-point concentration range. Gene expression profiling was conducted using the targeted TempO-Seq™ assay, and the TGx-DDI classifier was applied to the dataset. Classifications were compared with those based on the MicroFlow^® and MultiFlow^® assays. Benchmark Concentration (BMC) modeling was used for potency ranking. The results of the integrated hazard calls indicate that five of the data-poor compounds were genotoxic in vitro, causing DNA damage via a clastogenic MoA, and one via a pan-genotoxic MoA. Two compounds were likely irrelevant positives in the MN test; two are considered possibly genotoxic causing DNA damage via an ambiguous MoA. BMC modeling revealed nearly identical potency rankings for each assay. This ranking was maintained when all endpoint BMCs were converted into a single score using the Toxicological Prioritization (ToxPi) approach. Overall, this study contributes to the establishment of a modernized approach for effective genotoxicity assessment and chemical prioritization for further regulatory scrutiny. We conclude that the integration of TGx-DDI, MicroFlow^®, and MultiFlow^® endpoints is an effective NAM-based strategy for genotoxicity assessment of data-poor compounds.

Loss of SORCS2 is Associated with Neuronal DNA Double-Strand Breaks

SORCS2 is one of five proteins that constitute the Vps10p-domain receptor family. Members of this family play important roles in cellular processes linked to neuronal survival, differentiation and function. Genetic and functional studies implicate SORCS2 in cognitive function, as well as in neurodegenerative and psychiatric disorders. DNA damage and DNA repair deficits are linked to ageing and neurodegeneration, and transient neuronal DNA double-strand breaks (DSBs) also occur as a result of neuronal activity. Here, we report a novel role for SORCS2 in DSB formation. We show that SorCS2 loss is associated with elevated DSB levels in the mouse dentate gyrus and that knocking out SORCS2 in a human neuronal cell line increased Topoisomerase IIβ-dependent DSB formation and reduced neuronal viability. Neuronal stimulation had no impact on levels of DNA breaks in vitro, suggesting that the observed differences may not be the result of aberrant neuronal activity in these cells. Our findings are consistent with studies linking the VPS10 receptors and DNA damage to neurodegenerative conditions.

IND-2, a Quinoline Derivative, Inhibits the Proliferation of Prostate Cancer Cells by Inducing Oxidative Stress, Apoptosis and Inhibiting Topoisomerase II

In men, prostate cancer (PC) is the most frequently diagnosed cancer, causing an estimated 375,000 deaths globally. Currently, existing therapies for the treatment of PC, notably metastatic cases, have limited efficacy due to drug resistance and problematic adverse effects. Therefore, it is imperative to discover and develop novel drugs for treating PC that are efficacious and do not produce intolerable adverse or toxic effects. Condensed quinolines are naturally occurring anticancer compounds. In this study, we determined the in vitro efficacy of IND-2 (4-chloro-2-methylpyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinolone) in the PC lines, PC-3 and DU-145. IND-2 significantly inhibited the proliferation of PC-3 and DU-145, with IC₅₀ values of 3 µM and 3.5 µM, respectively. The incubation of PC-3 cells with 5 and 10 µM of IND-2 caused the loss of the mitochondrial membrane potential in PC-3 cells. Furthermore, IND-2, at 5 µM, increased the expression of cleaved caspase-3, cleaved caspase-7 and cleaved poly (ADP-ribose) polymerase (PARP). The incubation of PC-3 cells with 5 µM of IND-2 significantly decreased the expression of the apoptotic protein, B-cell lymphoma 2 (Bcl-2). Furthermore, 5 and 10 µM of IND-2 produced morphological changes in PC-3 cells characteristic of apoptosis. Interestingly, IND-2 (2.5, 5 and 10 µM) also induced mitotic catastrophe in PC-3 cells, characterized by the accumulation of multinuclei. The incubation of DU-145 cells with 1.25 and 5 μM of IND-2 significantly increased the levels of reactive oxygen species (ROS). Finally, IND-2, at 10 μM, inhibited the catalytic activity of topoisomerase IIα. Overall, our findings suggest that IND-2 could be a potential lead compound for the development of more efficacious compounds for the treatment of PC.

Molecular determinants of etoposide resistance in HL60 cells

Chemotherapy resistance is the main reason for treatment failure in acute myeloid leukemia (AML) and the major cause of its mortality. Etoposide is a DNA topoisomerase-II inhibitor that is used either as a single agent or in combination with cytarabine, azacytidine, vinca alkaloids, and anthracyclines for the treatment of relapsed /refractory AML. In this study, we sought to determine and understand the mechanism of etoposide resistance in AML using the HL60 cell line.HL60 cells were treated with incremental doses of etoposide and resistant colonies were isolated by culturing the resistant cells in semi-solid culture media. Three clones were selected for etoposide resistance namely, HL60-EtopR H1A, HL60-EtopR H1B, and HL60-EtopR H1C which demonstrated 4.78, 2.39, and 4.42-fold higher resistance to etoposide compared with the parental cells. To determine molecular differences between the etoposide-resistant HL60-EtopR cells and the parental cells, microarray-based gene expression profiling was performed. We found up regulation of members of the src tyrosine kinase family genes in the etoposide resistant cells. Further studies are required to evaluate the role of Src inhibitors in targeting etoposide resistant cells.

Drug Repurposing, a Fast-Track Approach to Develop Effective Treatments for Glioblastoma

Glioblastoma (GBM) remains one of the most difficult tumors to treat. The mean overall survival rate of 15 months and the 5-year survival rate of 5% have not significantly changed for almost 2 decades. Despite progress in understanding the pathophysiology of the disease, no new effective treatments to combine with radiation therapy after surgical tumor debulking have become available since the introduction of temozolomide in 1999. One of the main reasons for this is the scarcity of compounds that cross the blood-brain barrier (BBB) and reach the brain tumor tissue in therapeutically effective concentrations. In this review, we focus on the role of the BBB and its importance in developing brain tumor treatments. Moreover, we discuss drug repurposing, a drug discovery approach to identify potential effective candidates with optimal pharmacokinetic profiles for central nervous system (CNS) penetration and that allows rapid implementation in clinical trials. Additionally, we provide an overview of repurposed candidate drug currently being investigated in GBM at the preclinical and clinical levels. Finally, we highlight the importance of phase 0 trials to confirm tumor drug exposure and we discuss emerging drug delivery technologies as an alternative route to maximize therapeutic efficacy of repurposed candidate drug.

An Adaptive Role for DNA Double-Strand Breaks in Hippocampus-Dependent Learning and Memory

DNA double-strand breaks (DSBs), classified as the most harmful type of DNA damage based on the complexity of repair, lead to apoptosis or tumorigenesis. In aging, DNA damage increases and DNA repair decreases. This is exacerbated in disease, as post-mortem tissue from patients diagnosed with mild cognitive impairment (MCI) or Alzheimer's disease (AD) show increased DSBs. A novel role for DSBs in immediate early gene (IEG) expression, learning, and memory has been suggested. Inducing neuronal activity leads to increases in DSBs and upregulation of IEGs, while increasing DSBs and inhibiting DSB repair impairs long-term memory and alters IEG expression. Consistent with this pattern, mice carrying dominant AD mutations have increased baseline DSBs, and impaired DSB repair is observed. These data suggest an adaptive role for DSBs in the central nervous system and dysregulation of DSBs and/or repair might drive age-related cognitive decline (ACD), MCI, and AD. In this review, we discuss the adaptive role of DSBs in hippocampus-dependent learning, memory, and IEG expression. We summarize IEGs, the history of DSBs, and DSBs in synaptic plasticity, aging, and AD. DSBs likely have adaptive functions in the brain, and even subtle alterations in their formation and repair could alter IEGs, learning, and memory.

Infusion of etoposide in the CA1 disrupts hippocampal immediate early gene expression and hippocampus-dependent learning

Tight regulation of immediate early gene (IEG) expression is important for synaptic plasticity, learning, and memory. Recent work has suggested that DNA double strand breaks (DSBs) may have an adaptive role in post-mitotic cells to induce IEG expression. Physiological activity in cultured neurons as well as behavioral training leads to increased DSBs and subsequent IEG expression. Additionally, infusion of etoposide-a common cancer treatment that induces DSBs-impairs trace fear memory. Here, we assessed the effects of hippocampal infusion of 60 ng of etoposide on IEG expression, learning, and memory in 3-4 month-old C57Bl/6J mice. Etoposide altered expression of the immediate early genes cFos and Arc in the hippocampus and impaired hippocampus-dependent contextual fear memory. These data add to the growing evidence that DSBs play an important role in IEG expression, learning, and memory, opening avenues for developing novel treatment strategies for memory-related disorders.

Human papillomaviruses sensitize cells to DNA damage induced apoptosis by targeting the innate immune sensor cGAS

The cyclic GMP-AMP synthase (cGAS) is a critical regulator of the innate immune response acting as a sensor of double-strand DNAs from pathogens or damaged host DNA. Upon activation, cGAS signals through the STING/TBK1/IRF3 pathway to induce interferon expression. Double stranded DNA viruses target the cGAS pathway to facilitate infection. In HPV positive cells that stably maintain viral episomes, the levels of cGAS were found to be significantly increased over those seen in normal human keratinocytes. Furthermore the downstream effectors of the cGAS pathway, STING and IRF3, were fully active in response to signaling from the secondary messenger cGAMP or poly (dA:dT). In HPV positive cells cGAS was detected in both cytoplasmic puncta as well as in DNA damage induced micronuclei. E6 was responsible for increased levels of cGAS that was dependent on inhibition of p53. CRISPR-Cas9 mediated knockout of cGAS prevented activation of STING and IRF3 but had a minimal effect on viral replication. A primary function of cGAS in HPV positive cells was in response to treatment with etoposide or cisplatin which lead to increased levels of H2AX phosphorylation and activation of caspase 3/7 cleavage while having only a minimal effect on activation of homologous recombination repair factors ATM, ATR or CHK2. In HPV positive cells cGAS was found to regulate the levels of the phosphorylated non-homologous end-joining kinase, DNA-PK, which may contribute to H2AX phosphorylation along with other factors. Importantly cGAS was also responsible for increased levels of DNA breaks along with enhanced apoptosis in HPV positive cells but not in HFKs. This study identifies an important and novel role for cGAS in mediating the response of HPV positive cells to chemotherapeutic drugs.

Persistent infection by human papillomaviruses (HPV) is the major risk factor for development of cervical as well as other anogenital and oropharyngeal cancers. Innate immune surveillance pathways are important in determining whether HPV infections will be cleared or persist. The role and activity of cGAS, an innate immune DNA sensor, during HPV infection is still not well understood. In this study we characterized the activity of cGAS-STING pathway in cells that stably maintain high-risk HPV episomes and found it was fully active. Furthermore, our studies indicate that cGAS helps regulate the response to DNA damage causing drugs such as etoposide and cisplatin. Treatment with both drugs further increased the levels of cGAS in HPV positive cells and this was critical for causing DNA breaks along with apoptotic cell death. These findings identify a novel role of cGAS in HPV positive cells in regulating the response to chemotherapeutic DNA damaging agents.

Bioinformatics and System Biology Approach to Reveal the Interaction Network and the Therapeutic Implications for Non-Small Cell Lung Cancer Patients With COVID-19

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the leading cause of coronavirus disease-2019 (COVID-19), is an emerging global health crisis. Lung cancer patients are at a higher risk of COVID-19 infection. With the increasing number of non-small-cell lung cancer (NSCLC) patients with COVID-19, there is an urgent need of efficacious drugs for the treatment of COVID-19/NSCLC.

Methods: Based on a comprehensive bioinformatic and systemic biological analysis, this study investigated COVID-19/NSCLC interactional hub genes, detected common pathways and molecular biomarkers, and predicted potential agents for COVID-19 and NSCLC.

Results: A total of 122 COVID-19/NSCLC interactional genes and 21 interactional hub genes were identified. The enrichment analysis indicated that COVID-19 and NSCLC shared common signaling pathways, including cell cycle, viral carcinogenesis, and p53 signaling pathway. In total, 10 important transcription factors (TFs) and 44 microRNAs (miRNAs) participated in regulations of 21 interactional hub genes. In addition, 23 potential candidates were predicted for the treatment of COVID-19 and NSCLC.

Conclusion: This study increased our understanding of pathophysiology and screened potential drugs for COVID-19 and NSCLC.

Tight association of autophagy and cell cycle in leukemia cells

Background

Autophagy plays an essential role in maintaining cellular homeostasis and in the response to cellular stress. Autophagy is also involved in cell cycle progression, yet the relationship between these processes is not clearly defined.

Results

In exploring this relationship, we observed that the inhibition of autophagy impaired the G2/M phase-arresting activity of etoposide but enhanced the G1 phase-arresting activity of palbociclib. We further investigated the connection of basal autophagy and cell cycle by utilizing the autophagosome tracer dye Cyto-ID in two ways. First, we established a double-labeling flow-cytometric procedure with Cyto-ID and the DNA probe DRAQ5, permitting the cell cycle phase-specific determination of autophagy in live cells. This approach demonstrated that different cell cycle phases were associated with different autophagy levels: G1-phase cells had the lowest level, and G2/M-phase cells had the highest one. Second, we developed a flow-cytometric cell-sorting procedure based on Cyto-ID that separates cell populations into fractions with low, medium, and high autophagy. Cell cycle analysis of Cyto-ID-sorted cells confirmed that the high-autophagy fraction contained a much higher percentage of G2/M-phase cells than the low-autophagy fraction. In addition, Cyto-ID-based cell sorting also proved to be useful for assessing other autophagy-related processes: extracellular flux analysis revealed metabolic differences between the cell populations, with higher autophagy being associated with higher respiration, higher mitochondrial ATP production, and higher glycolysis.

Conclusion

This work provides clear evidence of high autophagy in G2/M-phase cells by establishing a novel cell sorting technique based on Cyto-ID.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00334-8.

An In Vitro Anticancer, Antioxidant, and Phytochemical Study on Water Extract of Kalanchoe daigremontiana Raym.-Hamet and H. Perrier

Kalanchoe species are succulents with anti-inflammatory, antioxidant, and analgesic properties, as well as cytotoxic activity. One of the most popular species cultivated in Europe is Kalanchoe daigremontiana Raym.-Hamet and H. Perrier. In our study, we analyzed the phytochemical composition of K. daigremontiana water extract using UHPLC-QTOF-MS and estimated the cytotoxic activity of the extract on human ovarian cancer SKOV-3 cells by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, flow cytometry, luminometric, and fluorescent microscopy techniques. The expression levels of 92 genes associated with cell death were estimated via real-time PCR. The antioxidant activity was assessed via flow cytometry on human keratinocyte HaCaT cell line. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical and FRAP (ferric-reducing antioxidant power) assays were also applied. We identified twenty bufadienolide compounds in the water extract and quantified eleven. Bersaldegenin-1,3,5-orthoacetate and bryophyllin A were present in the highest amounts (757.4 ± 18.7 and 573.5 ± 27.2 ng/mg dry weight, respectively). The extract showed significant antiproliferative and cytotoxic activity, induced depolarization of the mitochondrial membrane, and significantly arrested cell cycle in the S and G2/M phases of SKOV-3 cells. Caspases-3, 7, 8, and 9 were not activated during the treatment, which indicated non-apoptotic cell death triggered by the extract. Additionally, the extract increased the level of oxidative stress in the cancer cell line. In keratinocytes treated with menadione, the extract moderately reduced the level of oxidative stress. This antioxidant activity was confirmed by the DPPH and FRAP assays, where the obtained IC₅₀ values were 1750 ± 140 and 1271.82 ± 53.25 μg/mL, respectively. The real-time PCR analysis revealed that the extract may induce cell death via TNF receptor (tumor necrosis factor receptor) superfamily members 6 and 10.

Targeting the DNA Damage Response to Increase Anthracycline-Based Chemotherapy Cytotoxicity in T-Cell Lymphoma

Mature T-cell lymphomas (MTCLs) represent a heterogeneous group of aggressive non-Hodgkin lymphomas comprising different entities. Anthracycline-based regimens are considered the standard of care in the front-line treatment. However, responses to these approaches have been neither adequate nor durable, and new treatment strategies are urgently needed to improve survival. Genomic instability is a common feature of cancer cells and can be caused by aberrations in the DNA damage response (DDR) and DNA repair mechanisms. Consistently, molecules involved in DDR are being targeted to successfully sensitize cancer cells to chemotherapy. Recent studies showed that some hematological malignancies display constitutive DNA damage and intrinsic DDR activation, but these features have not been investigated yet in MTCLs. In this study, we employed a panel of malignant T cell lines, and we report for the first time the characterization of intrinsic DNA damage and basal DDR activation in preclinical models in T-cell lymphoma. Moreover, we report the efficacy of targeting the apical kinase ATM using the inhibitor AZD0156, in combination with standard chemotherapy to promote apoptotic cell death. These findings suggest that DDR is an attractive pathway to be pharmacologically targeted when developing novel therapies and improving MTCL patients’ outcomes.

HDAC Inhibitor Sodium Butyrate Attenuates the DNA Repair in Transformed but Not in Normal Fibroblasts

Many cancer therapy strategies cause DNA damage leading to the death of tumor cells. The DNA damage response (DDR) modulators are considered as promising candidates for use in combination therapy to enhance the efficacy of DNA-damage-mediated cancer treatment. The inhibitors of histone deacetylases (HDACis) exhibit selective antiproliferative effects against transformed and tumor cells and could enhance tumor cell sensitivity to genotoxic agents, which is partly attributed to their ability to interfere with DDR. Using the comet assay and host-cell reactivation of transcription, as well as γH2AX staining, we have shown that sodium butyrate inhibited DNA double-strand break (DSB) repair of both endo- and exogenous DNA in transformed but not in normal cells. According to our data, the dysregulation of the key repair proteins, especially the phosphorylated Mre11 pool decrease, is the cause of DNA repair impairment in transformed cells. The inability of HDACis to obstruct DSB repair in normal cells shown in this work demonstrates the advantages of HDACis in combination therapy with genotoxic agents to selectively enhance their cytotoxic activity in cancer cells.

Gamma-tocotrienol Synergistically Promotes the Anti-proliferative and Pro-apoptotic Effects of Etoposide on Breast Cancer Cell Lines

BACKGROUND

Breast Cancer is one of the most commonly diagnosed cancers worldwide and a major cause of death among women. Although chemotherapeutic agents remain the keystones in cancer therapy, significant side effects have failed to provide a safe and tolerable treatment for cancer patients. Dietary antioxidant vitamins were extensively investigated over the past years and their relevance in cancer chemotherapy remains to be elucidated.

OBJECTIVE

In the current study, we aimed to investigate the anti-proliferative and apoptotic effects of combining γ-tocotrienol, a member of the vitamin E family, with the chemotherapeutic drug etoposide in MCF-7 and MDA-MB-231 breast cancer cell lines.

METHODS

The antiproliferative effect of etoposide combined with γ-tocotrienol was measured using MTS viability reagent. The pro-apoptotic effect was elucidated through Cell Death ELISA and dual Annexin V/PI staining followed by flow cytometric analysis.

RESULTS

Our results showed that etoposide significantly decreased the cell growth of both cell lines with MDA-MB-231 cells being more sensitive to etoposide treatment than MCF-7. Moreover, the simultaneous treatment of both breast cancer cell lines with low doses of γ-tocotrienol and etoposide induced a synergistic antiproliferative effect (CI<1). Furthermore, the combination therapy significantly increased the percentage of total apoptotic cells in the MDA-MB-231 cell line and the degree of DNA fragmentation as compared to treatment with either compound alone.

CONCLUSION

In conclusion, our results provide evidence for the profound anti-tumorigenic effect of combined etoposide and γ-tocotrienol in the breast cancer cell lines.

CAMSAP1 Mutation Correlates With Improved Prognosis in Small Cell Lung Cancer Patients Treated With Platinum-Based Chemotherapy

Platinum-based chemotherapy is the first-line treatment for small cell lung cancer (SCLC). However, due to patients developing a resistance to the drug, most experience relapse and their cancer can become untreatable. A large number of recent studies have found that platinum drug sensitivity of various cancers is affected by specific gene mutations, and so with this study, we attempted to find an effective genetic biomarker in SCLC patients that indicates their sensitivity to platinum-based drugs. To do this, we first analyzed whole exome sequencing (WES) and clinical data from two cohorts to find gene mutations related to the prognosis and to the platinum drug sensitivity of SCLC patients. The cohorts used were the Zhujiang cohort (N = 138) and the cohort reported by George et al. (N = 101). We then carried out gene set variation analysis (GSVA) and gene set enrichment analysis (GSEA) to investigate possible molecular mechanisms through which these gene mutations affect patient prognosis and platinum drug sensitivity. We found that for SCLC patients, CAMSAP1 mutation can activate anti-tumor immunity, mediate tumor cell apoptosis, inhibit epithelial-mesenchymal transition (EMT), improve prognosis, and improve platinum drug sensitivity, suggesting that CAMSAP1 mutation may be a potential biomarker indicating platinum drug sensitivity and patient prognosis in SCLC.

Repurposing the Antibacterial Activity of Etoposide─A Chemotherapeutic Drug in Combination with Eggshell-Derived Hydroxyapatite

Drug repurposing has been gaining increasing interest recently due to the reduction in development cost and reduced development timelines. Here, we report the antibacterial activity of the anticancer drug etoposide investigated in combination with the eggshell-derived hydroxyapatite (EHA). Hydroxyapatite (HA) is a well-known bioactive material with enhanced osteoconductivity and possesses superior drug delivery properties. In the present work, we have synthesized etoposide-loaded EHA by the wet precipitation method. The physicochemical characterization of the samples confirmed the composition and amount of drug encapsulation. Screening for antibacterial activity confirmed the antibacterial effect of etoposide against Staphylococcus aureus. Biofilm formation test on pristine and etoposide-loaded samples showed the inhibition of biofilm formation on etoposide loading, which was further studied by confocal laser scanning microscopy (CLSM) and colony forming units (CFUs). It has been found that etoposide-loaded HA exhibited a sustained release of the drug upto 168 h. Analysis of the inhibition mechanism of etoposide against S. aureus revealed damage to the cell membrane and has been quantified using flow cytometry by the uptake of propidium iodide. Etoposide-loaded eggshell-derived HA (EHA-ET) exhibited excellent bioactivity and cytocompatibility against mouse fibroblast cells (L929) and supressed the growth of osteosarcoma cells (MG-63). Our studies reveal that the EHA-ET has a great potential for treating osteosarcoma and osteomyelitis.

Transcription Factor Activation Profiles (TFAP) identify compounds promoting differentiation of Acute Myeloid Leukemia cell lines

Repurposing of drugs for new therapeutic use has received considerable attention for its potential to limit time and cost of drug development. Here we present a new strategy to identify chemicals that are likely to promote a desired phenotype. We used data from the Connectivity Map (CMap) to produce a ranked list of drugs according to their potential to activate transcription factors that mediate myeloid differentiation of leukemic progenitor cells. To validate our strategy, we tested the in vitro differentiation potential of candidate compounds using the HL-60 human cell line as a myeloid differentiation model. Ten out of 22 compounds, which were ranked high in the inferred list, were confirmed to promote significant differentiation of HL-60. These compounds may be considered candidate for differentiation therapy. The method that we have developed is versatile and it can be adapted to different drug repurposing projects.

Mitochondrial glutamine metabolism regulates sensitivity of cancer cells after chemotherapy via amphiregulin

The DNA damage response is essential for sustaining genomic stability and preventing tumorigenesis. However, the fundamental question about the cellular metabolic response to DNA damage remains largely unknown, impeding the development of metabolic interventions that might prevent or treat cancer. Recently, it has been reported that there is a link between cell metabolism and DNA damage response, by repression of glutamine (Gln) entry into mitochondria to support cell cycle arrest and DNA repair. Here, we show that mitochondrial Gln metabolism is a crucial regulator of DNA damage-induced cell death. Mechanistically, inhibition of glutaminase (GLS), the first enzyme for Gln anaplerosis, sensitizes cancer cells to DNA damage by inducing amphiregulin (AREG) that promotes apoptotic cell death. GLS inhibition increases reactive oxygen species production, leading to transcriptional activation of AREG through Max-like protein X (MLX) transcription factor. Moreover, suppression of mitochondrial Gln metabolism results in markedly increased cell death after chemotherapy in vitro and in vivo. The essentiality of this molecular pathway in DNA damage-induced cell death may provide novel metabolic interventions for cancer therapy.

Cell survival after DNA damage in the comet assay

The comet assay is widely used in basic research, genotoxicity testing, and human biomonitoring. However, interpretation of the comet assay data might benefit from a better understanding of the future fate of a cell with DNA damage. DNA damage is in principle repairable, or if extensive, can lead to cell death. Here, we have correlated the maximally induced DNA damage with three test substances in TK6 cells with the survival of the cells. For this, we selected hydrogen peroxide (H2O2) as an oxidizing agent, methyl methanesulfonate (MMS) as an alkylating agent and etoposide as a topoisomerase II inhibitor. We measured cell viability, cell proliferation, apoptosis, and micronucleus frequency on the following day, in the same cell culture, which had been analyzed in the comet assay. After treatment, a concentration dependent increase in DNA damage and in the percentage of non-vital and apoptotic cells was found for each substance. Values greater than 20-30% DNA in tail caused the death of more than 50% of the cells, with etoposide causing slightly more cell death than H2O2 or MMS. Despite that, cells seemed to repair of at least some DNA damage within few hours after substance removal. Overall, the reduction of DNA damage over time is due to both DNA repair and death of heavily damaged cells. We recommend that in experiments with induction of DNA damage of more than 20% DNA in tail, survival data for the cells are provided.

One oncogene, several vulnerabilities: EWS/FLI targeted therapies for Ewing sarcoma

EWS/FLI is the defining mutation of Ewing sarcoma. This oncogene drives malignant transformation and progression and occurs in a genetic background characterized by few other recurrent cooperating mutations. In addition, the tumor is absolutely dependent on the continued expression of EWS/FLI to maintain the malignant phenotype. However, EWS/FLI is a transcription factor and therefore a challenging drug target. The difficulty of directly targeting EWS/FLI stems from unique features of this fusion protein as well as the network of interacting proteins required to execute the transcriptional program. This network includes interacting proteins as well as upstream and downstream effectors that together reprogram the epigenome and transcriptome. While the vast number of proteins involved in this process challenge the development of a highly specific inhibitors, they also yield numerous therapeutic opportunities. In this report, we will review how this vast EWS-FLI transcriptional network has been exploited over the last two decades to identify compounds that directly target EWS/FLI and/or associated vulnerabilities.

Involvement of classic and alternative non-homologous end joining pathways in hematologic malignancies: targeting strategies for treatment

Chromosomal translocations are the main etiological factor of hematologic malignancies. These translocations are generally the consequence of aberrant DNA double-strand break (DSB) repair. DSBs arise either exogenously or endogenously in cells and are repaired by major pathways, including non-homologous end-joining (NHEJ), homologous recombination (HR), and other minor pathways such as alternative end-joining (A-EJ). Therefore, defective NHEJ, HR, or A-EJ pathways force hematopoietic cells toward tumorigenesis. As some components of these repair pathways are overactivated in various tumor entities, targeting these pathways in cancer cells can sensitize them, especially resistant clones, to radiation or chemotherapy agents. However, targeted therapy-based studies are currently underway in this area, and furtherly there are some biological pitfalls, clinical issues, and limitations related to these targeted therapies, which need to be considered. This review aimed to investigate the alteration of DNA repair elements of C-NHEJ and A-EJ in hematologic malignancies and evaluate the potential targeted therapies against these pathways.

Nucleolar translocation of human DNA topoisomerase II by ATP depletion and its disruption by the RNA polymerase I inhibitor BMH-21

DNA topoisomerase II (TOP2) is a nuclear protein that resolves DNA topological problems and plays critical roles in multiple nuclear processes. Human cells have two TOP2 proteins, TOP2A and TOP2B, that are localized in both the nucleoplasm and nucleolus. Previously, ATP depletion was shown to augment the nucleolar localization of TOP2B, but the molecular details of subnuclear distributions, particularly of TOP2A, remained to be fully elucidated in relation to the status of cellular ATP. Here, we analyzed the nuclear dynamics of human TOP2A and TOP2B in ATP-depleted cells. Both proteins rapidly translocated from the nucleoplasm to the nucleolus in response to ATP depletion. FRAP analysis demonstrated that they were highly mobile in the nucleoplasm and nucleolus. The nucleolar retention of both proteins was sensitive to the RNA polymerase I inhibitor BMH-21, and the TOP2 proteins in the nucleolus were immediately dispersed into the nucleoplasm by BMH-21. Under ATP-depleted conditions, the TOP2 poison etoposide was less effective, indicating the therapeutic relevance of TOP2 subnuclear distributions. These results give novel insights into the subnuclear dynamics of TOP2 in relation to cellular ATP levels and also provide discussions about its possible mechanisms and biological significance.

Unravelling the Anticancer Mechanisms of Traditional Herbal Medicines with Metabolomics

Metabolite profiling of cancer cells presents many opportunities for anticancer drug discovery. The Chinese, Indian, and African flora, in particular, offers a diverse source of anticancer therapeutics as documented in traditional folklores. In-depth scientific information relating to mechanisms of action, quality control, and safety profile will promote their extensive usage in cancer therapy. Metabolomics may be a more holistic strategy to gain valuable insights into the anticancer mechanisms of action of plants but this has remained largely unexplored. This review, therefore, presents the available metabolomics studies on the anticancer effects of herbal medicines commonly used in Africa and Asia. In addition, we present some scientifically understudied ‘candidate plants’ for cancer metabolomics studies and highlight the relevance of metabolomics in addressing other challenges facing the drug development of anticancer herbs. Finally, we discussed the challenges of using metabolomics to uncover the underlying mechanisms of potential anticancer herbs and the progress made in this regard.

Molecular events in neuroendocrine prostate cancer development

Neuroendocrine prostate cancer (NEPC) is a lethal subtype of prostate cancer. NEPC arises de novo only rarely; the disease predominantly develops from adenocarcinoma in response to drug-induced androgen receptor signalling inhibition, although the mechanisms behind this transdifferentiation are a subject of debate. The survival of patients with NEPC is poor, and few effective treatment options are available. To improve clinical outcomes, understanding of the biology and molecular mechanisms regulating NEPC development is crucial. Various NEPC molecular drivers make temporal contributions during NEPC development, and despite the limited treatment options available, several novel targeted therapeutics are currently under research.

Quantifying Cytosolic Cytochrome c Concentration Using Carbon Quantum Dots as a Powerful Method for Apoptosis Detection

BACKGROUND

Cytochrome c (Cyt c) is a key biomarker for early apoptosis, and many methods were designed to detect its release from mitochondria. For a proper evaluation of these programed cell death mechanisms, fluorescent nanoparticles are excellent candidates due to their valuable optical properties. Among all classes of nanoparticles developed thus far, carbon-based quantum dots bring qualitative and efficient imaging strategies for biomedical applications as a consequence of their biocompatibility and low cytotoxicity.

METHODS

In this study, we synthesized carbon quantum dots smaller than 5 nm from sodium citrate and polyethylene imine. These nanoparticles were rigorously characterized, and their quenching capacity in apoptotic events was assessed in A549 cells treated with staurosporine and etoposide. For the evaluation of Cyt c release, a phenomenon directly correlated with apoptotic events, we ran a semiquantitative analysis using confocal laser scanning microscopy.

RESULTS

Carbon quantum dots were synthesized and were successfully employed for Cyt c detection by means of fluorescence microscopy. Significant drops in fluorescence intensity were observed in the case of cells treated with apoptosis-inducing therapeutic compounds compared to untreated cells, confirming Cyt c release from mitochondria to cytosol.

CONCLUSION

Considering these results, we strongly believe this method can contribute to an indirect in vitro evaluation of apoptosis.

Synergistic Effect of Simultaneous versus Sequential Combined Treatment of Histone Deacetylase Inhibitor Valproic Acid with Etoposide on Melanoma Cells

Melanoma is the most lethal form of skin cancer, which is intrinsically resistant to conventional chemotherapy. Combination therapy has been developed to overcome this challenge and show synergistic anticancer effects on melanoma. Notably, the histone deacetylase inhibitor, valproic acid (VPA), has been indicated as a potential sensitizer of chemotherapy drugs on various metastatic cancers, including advanced melanoma. In this study, we explored whether VPA could serve as an effective sensitizer of chemotherapy drug etoposide (ETO) on B16-F10 and SK-MEL-2-Luc melanoma cell lines in response to drug-induced DNA damages. Our results demonstrated that the VPA-ETO simultaneous combined treatment and ETO pretreated sequential combined treatment generated higher inhibitory effectivities than the individual treatment of each drug. We found the VPA-ETO simultaneous combined treatment contributed to the synergistic inhibitory effect by the augmented DNA double-strand breaks, accompanied by a compromised homologous recombination activity. In comparison, the ETO pretreated sequential combined treatment led to synergistic inhibitory effect via enhanced apoptosis. Surprisingly, the enhanced homologous recombination activity and G2/M phase arrest resulted in the antagonistic effect in both cells under VPA pretreated sequential combined treatment. In summary, our findings suggested that sequential order and effective dose of drug administration in VPA-ETO combination therapy could induce different cellular responses in melanoma cells. Such understanding might help potentiate the effectiveness of melanoma treatment and highlight the importance of sequential order and effective dose in combination therapy.