Genotoxic anti-cancer agents and their relationship to DNA damage, mitosis, and checkpoint adaptation in proliferating cancer cells

Dual-targeted nanoparticulate drug delivery systems for enhancing triple-negative breast cancer treatment

The efficacy of DNA-damaging agents, such as the topoisomerase I inhibitor SN38, is often compromised by the robust DNA repair mechanisms in tumor cells, notably homologous recombination (HR) repair. Addressing this challenge, we introduce a novel nano-strategy utilizing binary tumor-killing mechanisms to enhance the therapeutic impact of DNA damage and mitochondrial dysfunction in cancer treatment. Our approach employs a synergistic drug pair comprising SN38 and the BET inhibitor JQ-1. We synthesized two prodrugs by conjugating linoleic acid (LA) to SN38 and JQ-1 via a cinnamaldehyde thioacetal (CT) bond, facilitating co-delivery. These prodrugs co-assemble into a nanostructure, referred to as SJNP, in an optimal synergistic ratio. SJNP was validated for its efficacy at both the cellular and tissue levels, where it primarily disrupts the transcription factor protein BRD4. This disruption leads to downregulation of BRCA1 and RAD51, impairing the HR process and exacerbating DNA damage. Additionally, SJNP releases cinnamaldehyde (CA) upon CT linkage cleavage, elevating intracellular ROS levels in a self-amplifying manner and inducing ROS-mediated mitochondrial dysfunction. Our results indicate that SJNP effectively targets murine triple-negative breast cancer (TNBC) with minimal adverse toxicity, showcasing its potential as a formidable opponent in the fight against cancer.

H2AX: A key player in DNA damage response and a promising target for cancer therapy

Cancer is caused by a complex interaction of factors that interrupt the normal growth and division of cells. At the center of this process is the intricate relationship between DNA damage and the cellular mechanisms responsible for maintaining genomic stability. When DNA damage is not repaired, it can cause genetic mutations that contribute to the initiation and progression of cancer. On the other hand, the DNA damage response system, which involves the phosphorylation of the histone variant H2AX (γH2AX), is crucial in preserving genomic integrity by signaling and facilitating the repair of DNA double-strand breaks. This review provides an explanation of the molecular dynamics of H2AX in the context of DNA damage response. It emphasizes the crucial role of H2AX in recruiting and localizing repair machinery at sites of chromatin damage. The review explains how H2AX phosphorylation, facilitated by the master kinases ATM and ATR, acts as a signal for DNA damage, triggering downstream pathways that govern cell cycle checkpoints, apoptosis, and the cellular fate decision between repair and cell death. The phosphorylation of H2AX is a critical regulatory point, ensuring cell survival by promoting repair or steering cells towards apoptosis in cases of catastrophic genomic damage. Moreover, we explore the therapeutic potential of targeting H2AX in cancer treatment, leveraging its dual function as a biomarker of DNA integrity and a therapeutic target. By delineating the pathways that lead to H2AX phosphorylation and its roles in apoptosis and cell cycle control, we highlight the significance of H2AX as both a prognostic tool and a focal point for therapeutic intervention, offering insights into its utility in enhancing the efficacy of cancer treatments.

Medicinal and chemosensing applications of chitosan based material: A review

Chitosan (CTS), has emerged as a highly intriguing biopolymer with widespread applications, drawing significant attention in various fields ranging from medicinal to chemosensing. Key characteristics of chitosan include solubility, biocompatibility, biodegradability and reactivity, making it versatile in numerous sectors. Several derivatives have been documented for their diverse therapeutic properties, such as antibacterial, antifungal, anti-diabetic, anti-inflammatory, anticancer and antioxidant activities. Furthermore, these compounds serve as highly sensitive and selective chemosensor for the detection of various analytes such as heavy metal ions, anions and various other species in agricultural, environmental and biological matrixes. CTS derivatives interacting with these species and give analytical signals. In this review, we embark on an exploration of the latest advancements in CTS-based materials, emphasizing their noteworthy contributions to medicinal chemistry spanning the years from 2021 to 2023. The intrinsic biological and physiological properties of CTS make it an ideal platform for designing materials that interact seamlessly with biological systems. The review also explores the utilization of chitosan-based materials for the development of colorimetric and fluorimetric chemosensors capable of detecting metal ions, anions and various other species, contributing to advancements in environmental monitoring, healthcare diagnostics, and industrial processes.

The complexity of extracellular vesicles: Bridging the gap between cellular communication and neuropathology

Brain-derived extracellular vesicles (EVs) serve a prominent role in maintaining homeostasis and contributing to pathology in health and disease. This review establishes a crucial link between physiological processes leading to EV biogenesis and their impacts on disease. EVs are involved in the clearance and transport of proteins and nucleic acids, responding to changes in cellular processes associated with neurodegeneration, including autophagic disruption, organellar dysfunction, aging, and other cell stresses. In neurodegenerative disorders (e.g., Alzheimer's disease, Parkinson's disease, etc.), EVs contribute to the spread of pathological proteins like amyloid β, tau, ɑ-synuclein, prions, and TDP-43, exacerbating neurodegeneration and accelerating disease progression. Despite evidence for both neuropathological and neuroprotective effects of EVs, the mechanistic switch between their physiological and pathological functions remains elusive, warranting further research into their involvement in neurodegenerative disease. Moreover, owing to their innate ability to traverse the blood-brain barrier and their ubiquitous nature, EVs emerge as promising candidates for novel diagnostic and therapeutic strategies. The review uniquely positions itself at the intersection of EV cell biology, neurophysiology, and neuropathology, offering insights into the diverse biological roles of EVs in health and disease.

Methylation of histone H3 lysine 36 is a barrier for therapeutic interventions of head and neck squamous cell carcinoma

Approximately 20% of head and neck squamous cell carcinomas (HNSCCs) exhibit reduced methylation on lysine 36 of histone H3 (H3K36me) due to mutations in histone methylase NSD1 or a lysine-to-methionine mutation in histone H3 (H3K36M). Whether such alterations of H3K36me can be exploited for therapeutic interventions is still unknown. Here, we show that HNSCC models expressing H3K36M can be divided into two groups: those that display aberrant accumulation of H3K27me3 and those that maintain steady levels of H3K27me3. The former group exhibits reduced proliferation, genome instability, and heightened sensitivity to genotoxic agents like PARP1/2 inhibitors. Conversely, H3K36M HNSCC models with constant H3K27me3 levels lack these characteristics unless H3K27me3 is elevated by DNA hypomethylating agents or inhibiting H3K27me3 demethylases KDM6A/B. Mechanistically, H3K36M reduces H3K36me by directly impeding the activities of the histone methyltransferase NSD3 and the histone demethylase LSD2. Notably, aberrant H3K27me3 levels induced by H3K36M expression are not a bona fide epigenetic mark because they require continuous expression of H3K36M to be inherited. Moreover, increased sensitivity to PARP1/2 inhibitors in H3K36M HNSCC models depends solely on elevated H3K27me3 levels and diminishing BRCA1- and FANCD2-dependent DNA repair. Finally, a PARP1/2 inhibitor alone reduces tumor burden in a H3K36M HNSCC xenograft model with elevated H3K27me3, whereas in a model with consistent H3K27me3, a combination of PARP1/2 inhibitors and agents that up-regulate H3K27me3 proves to be successful. These findings underscore the crucial balance between H3K36 and H3K27 methylation in maintaining genome instability, offering new therapeutic options for patients with H3K36me-deficient tumors.

Differential DNA damage response and cell fate in human lung cells after exposure to genotoxic compounds

DNA damage can impair normal cellular functions and result in various pathophysiological processes including cardiovascular diseases and cancer. We compared the genotoxic potential of diverse DNA damaging agents, and focused on their effects on the DNA damage response (DDR) and cell fate in human lung cells BEAS-2B. Polycyclic aromatic hydrocarbons [PAHs; benzo[a]pyrene (B[a]P), 1-nitropyrene (1-NP)] induced DNA strand breaks and oxidative damage to DNA; anticancer drugs doxorubicin (DOX) and 5-bromo-2'-deoxyuridine (BrdU) were less effective. DOX triggered the most robust p53 signaling indicating activation of DDR, followed by cell cycle arrest in the G2/M phase, induction of apoptosis and senescence, possibly due to the severe and irreparable DNA lesions. BrdU not only activated p53, but also increased the percentage of G1-phased cells and caused a massive accumulation of senescent cells. In contrast, regardless the activation of p53, both PAHs did not substantially affect the cell cycle distribution or senescence. Finally, a small fraction of cells accumulated only in the G2/M phase and exhibited increased cell death after the prolonged incubation with B[a]P. Overall, we characterized differential responses to diverse DNA damaging agents resulting in specific cell fate and highlighted the key role of DNA lesion type and the p53 signaling persistence.

Effect of Polyphenolic Composition BP-C2 on Lung Carcinogenesis Induced by Urethane in Progeny of Irradiated Male BALB/c Mice

We studied the effects of polyphenolic composition BP-C2, comprising molybdenum with lignin derivatives, on lung carcinogenesis induced by urethane in the progeny of F0 male BALB/c mice preconceptionally exposed to radiation in a dose of 1 Gy. The multiplicity of lung tumors in the progeny of irradiated mice was higher than in the progeny of non-irradiated male parents by 50% in females and 43% in males (p<0.05). In F1 mice (progeny of irradiated F0 male parents treated with BP-C2), the multiplicity of lung tumors was also higher, but this increase was less pronounced: 35% in females (p=0.3852) and 23% in males (p=0.0766). We have demonstrated that administration of BP-C2 to irradiated parents (F0) efficiently inhibits carcinogenesis in their F1 progeny. The use of BP-C2 in irradiated male parents and their progeny not only reduced the multiplicity of tumors, but also normalized body weights in the F1 progeny. Our study demonstrates potential of the polyphenolic composition BP-C2 for chemoprophylaxis of radiation-induced transgenerational carcinogenesis.

Methylation of histone H3 lysine 36 is a barrier for therapeutic interventions of head and neck squamous cell carcinoma

Approximately 20% of head and neck squamous cell carcinomas (HNSCC) exhibit reduced methylation on lysine 36 of histone H3 (H3K36me) due to mutations in histone methylase NSD1 or a lysine-to-methionine mutation in histone H3 (H3K36M). Whether such alterations of H3K36me can be exploited for therapeutic interventions is still unknown. Here, we show that HNSCC models expressing H3K36M can be divided into two groups: those that display aberrant accumulation of H3K27me3 and those that maintain steady levels of H3K27me3. The first group shows decreased proliferation, genome instability, and increased sensitivity to genotoxic agents, such as PARP1/2 inhibitors. In contrast, the H3K36M HNSCC models with steady H3K27me3 levels do not exhibit these characteristics unless H3K27me3 levels are elevated, either by DNA hypomethylating agents or by inhibiting the H3K27me3 demethylases KDM6A/B. Mechanistically, we found that H3K36M reduces H3K36me by directly impeding the activities of the histone methyltransferase NSD3 and the histone demethylase LSD2. Notably, we found that aberrant H3K27me3 levels induced by H3K36M expression is not a bona fide epigenetic mark in HNSCC since it requires continuous expression of H3K36M to be inherited. Moreover, increased sensitivity of H3K36M HNSCC models to PARP1/2 inhibitors solely depends on the increased H3K27me3 levels. Indeed, aberrantly high H3K27me3 levels decrease BRCA1 and FANCD2-dependent DNA repair, resulting in higher sensitivity to DNA breaks and replication stress. Finally, in support of our in vitro findings, a PARP1/2 inhibitor alone reduce tumor burden in a H3K36M HNSCC xenograft model with elevated H3K27me3, whereas in a H3K36M HNSCC xenograft model with consistent H3K27me3 levels, a combination of PARP1/2 inhibitors and agents that upregulate H3K27me3 proves to be successful. In conclusion, our findings underscore a delicate balance between H3K36 and H3K27 methylation, essential for maintaining genome stability. This equilibrium presents promising therapeutic opportunities for patients with H3K36me-deficient tumors.

The role of ginger's extract and N-acetylcysteine against docetaxel-induced oxidative stress and genetic disorder

Oxidative stress plays a prominent role in expanding toxicity and various diseases. This study investigated the potential protective effects of ginger (Zingiber officinale) rhizome extract and NAC on docetaxel induced genotoxicity and oxidative stress. The antioxidant power of NAC and ginger extract on the genetic toxicity induced by docetaxel was assessed by micronucleus test. The ROS test with DCFH reagent was used to assess the reactive oxygen species. The thiobarbituric acid method was used to evaluate the amount of MDA produced by docetaxel. The amounts of phenol and flavonoids in the ginger extracts were also evaluated. The amount of phenol in the ginger extract was 0.886 mg of gallic acid per gram of dry extract. The amount of flavonoids were 0.242 mg/mL of quercetin per gram of dry extract. As shown by the micronucleus results, concentrations of 100 and 500 μM NAC and all concentrations of the ginger extract significantly reduced the number of micronuclei produced by docetaxel. On the other hand, the results of oxidative stress tests (ROS and LPO) showed that docetaxel in HGF cells increased the production of ROS and LPO, and the concentrations of ginger extract and NAC decreased oxidative stress in HGF cells in a dose-dependent manner. The results indicate that using these two antioxidants helps inhibit genetic toxicity and oxidative stress caused by docetaxel.

Cellular signaling modulated by miRNA-3652 in ovarian cancer: unveiling mechanistic pathways for future therapeutic strategies

MicroRNAs (miRNAs) are small non-coding RNA molecules that play pivotal roles in regulating gene expression and have been implicated in the pathogenesis of numerous cancers. miRNA-3652, though relatively less explored, has recently emerged as a potential key player in ovarian cancer's molecular landscape. This review aims to delineate the functional significance and tumor progression role of miRNA-3652 in ovarian cancer, shedding light on its potential as both a diagnostic biomarker and therapeutic target. A comprehensive literature search was carried out using established databases, the focus was on articles that reported the role of miRNA-3652 in ovarian cancer, encompassing mechanistic insights, functional studies, and its association with clinical outcomes. This updated review highlighted that miRNA-3652 is intricately involved in ovarian cancer cell proliferation, migration, and invasion, its dysregulation was linked to altered expression of critical genes involved in tumor growth and metastasis; furthermore, miRNA-3652 expression levels were found to correlate with clinical stages, prognosis, and response to therapy in ovarian cancer patients. miRNA-3652 holds significant promise as a vital molecular player in ovarian cancer's pathophysiology. Its functional role and impact on tumor progression make it a potential candidate for diagnostic and therapeutic applications in ovarian cancer. Given the pivotal role of miRNA-3652 in ovarian cancer, future studies should emphasize in-depth mechanistic explorations, utilizing advanced genomic and proteomic tools. Collaboration between basic scientists and clinicians will be vital to translating these findings into innovative diagnostic and therapeutic strategies, ultimately benefiting ovarian cancer patients. Video Abstract.

Anticancer Potential of the Plant-Derived Saponin Gracillin: A Comprehensive Review of Mechanistic Approaches

With the increasing prevalence of cancer and the toxic side effects of synthetic drugs, natural products are being developed as promising therapeutic approaches. Gracillin is a naturally occurring triterpenoid steroidal saponin with several therapeutic activities. It is obtained as a major compound from different Dioscorea species. This review was designated to summarize the research progress on the anti-cancer activities of gracillin focusing on the underlying cellular and molecular mechanisms, as well as its pharmacokinetic features. The data were collected (up to date as of May 1, 2023) from various reliable and authentic literatures comprising PubMed, Springer Link, Scopus, Wiley Online, Web of Science, ScienceDirect, and Google Scholar. The findings demonstrated that gracillin displays promising anticancer effects through various molecular mechanisms, including anti-inflammatory effects, apoptotic cell death, induction of oxidative stress, cytotoxicity, induction of genotoxicity, cell cycle arrest, anti-proliferative effect, autophagy, inhibition of glycolysis, and blocking of cancer cell migration. Additionally, this review highlighted the pharmacokinetic features of gracillin, indicating its lower oral bioavailability. As a conclusion, it can be proposed that gracillin could serve as a hopeful chemotherapeutic agent. However, further extensive clinical research is recommended to establish its safety, efficacy, and therapeutic potential in cancer treatment.

Prediction of hub genes and key pathways associated with the radiation response of human hematopoietic stem/progenitor cells using integrated bioinformatics methods

Hematopoietic stem cells (HSCs) are indispensable for the maintenance of the entire blood program through cytokine response. However, HSCs have high radiosensitivity, which is often a problem during radiation therapy and nuclear accidents. Although our previous study has reported that the combination cytokine treatment (interleukin-3, stem cell factor, and thrombopoietin) improves the survival of human hematopoietic stem/progenitor cells (HSPCs) after radiation, the mechanism by which cytokines contribute to the survival of HSPCs is largely unclear. To address this issue, the present study characterized the effect of cytokines on the radiation-induced gene expression profile of human CD34⁺ HSPCs and explored the hub genes that play key pathways associated with the radiation response using a cDNA microarray, a protein-protein interaction-MCODE module analysis and Cytohubba plugin tool in Cytoscape. This study identified 2,733 differentially expressed genes (DEGs) and five hub genes (TOP2A, EZH2, HSPA8, GART, HDAC1) in response to radiation in only the presence of cytokines. Furthermore, functional enrichment analysis found that hub genes and top DEGs based on fold change were enriched in the chromosome organization and organelle organization. The present findings may help predict the radiation response and improve our understanding of this response of human HSPCs.

MDM2 Inhibition in the Treatment of Glioblastoma: From Concept to Clinical Investigation

Inhibition of the interaction between MDM2 and p53 has emerged as a promising strategy for combating cancer, including the treatment of glioblastoma (GBM). Numerous MDM2 inhibitors have been developed and are currently undergoing rigorous testing for their potential in GBM therapy. Encouraging results from studies conducted in cell culture and animal models suggest that MDM2 inhibitors could effectively treat a specific subset of GBM patients with wild-type TP53 or functional p53. Combination therapy with clinically established treatment modalities such as radiation and chemotherapy offers the potential to achieve a more profound therapeutic response. Furthermore, an increasing array of other molecularly targeted therapies are being explored in combination with MDM2 inhibitors to increase the effects of individual treatments. While some MDM2 inhibitors have progressed to early phase clinical trials in GBM, their efficacy, alone and in combination, is yet to be confirmed. In this article, we present an overview of MDM2 inhibitors currently under preclinical and clinical investigation, with a specific focus on the drugs being assessed in ongoing clinical trials for GBM patients.

Neddylation inhibition sensitises renal medullary carcinoma tumours to platinum chemotherapy

BACKGROUND

Renal medullary carcinoma (RMC) is a highly aggressive cancer in need of new therapeutic strategies. The neddylation pathway can protect cells from DNA damage induced by the platinum-based chemotherapy used in RMC. We investigated if neddylation inhibition with pevonedistat will synergistically enhance antitumour effects of platinum-based chemotherapy in RMC.

METHODS

We evaluated the IC50 concentrations of the neddylation-activating enzyme inhibitor pevonedistat in vitro in RMC cell lines. Bliss synergy scores were calculated using growth inhibition assays following treatment with varying concentrations of pevonedistat and carboplatin. Protein expression was assessed by western blot and immunofluorescence assays. The efficacy of pevonedistat alone or in combination with platinum-based chemotherapy was evaluated in vivo in platinum-naïve and platinum-experienced patient-derived xenograft (PDX) models of RMC.

RESULTS

The RMC cell lines demonstrated IC50 concentrations of pevonedistat below the maximum tolerated dose in humans. When combined with carboplatin, pevonedistat demonstrated a significant in vitro synergistic effect. Treatment with carboplatin alone increased nuclear ERCC1 levels used to repair the interstrand crosslinks induced by platinum salts. Conversely, the addition of pevonedistat to carboplatin led to p53 upregulation resulting in FANCD2 suppression and reduced nuclear ERCC1 levels. The addition of pevonedistat to platinum-based chemotherapy significantly inhibited tumour growth in both platinum-naïve and platinum-experienced PDX models of RMC (p < .01).

CONCLUSIONS

Our results suggest that pevonedistat synergises with carboplatin to inhibit RMC cell and tumour growth through inhibition of DNA damage repair. These findings support the development of a clinical trial combining pevonedistat with platinum-based chemotherapy for RMC.

Homologous recombination suppresses transgenerational DNA end resection and chromosomal instability in fission yeast

Chromosomal instability (CIN) drives cell-to-cell heterogeneity, and the development of genetic diseases, including cancer. Impaired homologous recombination (HR) has been implicated as a major driver of CIN, however, the underlying mechanism remains unclear. Using a fission yeast model system, we establish a common role for HR genes in suppressing DNA double-strand break (DSB)-induced CIN. Further, we show that an unrepaired single-ended DSB arising from failed HR repair or telomere loss is a potent driver of widespread CIN. Inherited chromosomes carrying a single-ended DSB are subject to cycles of DNA replication and extensive end-processing across successive cell divisions. These cycles are enabled by Cullin 3-mediated Chk1 loss and checkpoint adaptation. Subsequent propagation of unstable chromosomes carrying a single-ended DSB continues until transgenerational end-resection leads to fold-back inversion of single-stranded centromeric repeats and to stable chromosomal rearrangements, typically isochromosomes, or to chromosomal loss. These findings reveal a mechanism by which HR genes suppress CIN and how DNA breaks that persist through mitotic divisions propagate cell-to-cell heterogeneity in the resultant progeny.

High concentration of γ‑H2AX correlates with a marker of apoptotic suppression and PI3K/Akt pathway upregulation in glioblastoma multiforme

Glioblastoma multiforme (GBM) is a very aggressive type of primary brain tumor in adults with a poor prognosis. DNA double-strand breaks are known to be associated with the development of numerous cancer types due to their ability to generate genomic instabilities. In GBM, the phosphatidylinositol 3-kinase (PI3K)/Akt pathway is a common pathway that can be activated by exogenous and endogenous factors. Genomic instability may be an endogenous stimulating factor for activation of the PI3K/Akt pathway, which may inhibit the apoptosis of GBM cells. Spontaneous DNA double-strand breaks play an essential role in the survival of GBM cells, and apoptosis levels may reflect survival ability. However, no study has yet been conducted to analyse the association between spontaneous DNA double-strand breaks and apoptosis in patients with GBM prior to treatment. Therefore, the present study examined the concentrations of γ-histone 2AX (γ-H2AX), a sensitive marker of spontaneous DNA double-strand breaks, and cleaved caspase-3, a marker of apoptosis, in patients with GBM. The correlation of γ-H2AX with cleaved caspase-3, PI3K and Akt was also investigated. A total of 26 pre-treatment tumor tissue specimens from patient with GBM were analyzed to determine the concentrations of γ-H2AX, PI3K, Akt and cleaved caspase-3 using sandwich enzyme-linked immunosorbent assays. The results showed a moderate positive correlation between γ-H2AX and PI3K (r=0.52; P=0.007), a moderate positive correlation between γ-H2AX and Akt (r=0.4; P=0.041) and a strong negative correlation between γ-H2AX and cleaved caspase-3 (r=-0.61; P=0.0009). These analyses were also performed in seven tumor tissue specimens from patients with grade I glioma as controls, but no significant correlations were detected. The findings of the present study suggest that a high level of γ-H2AX may affect GBM cell apoptosis via the PI3K/Akt pathway.

Amelioration of cyclophosphamide-induced DNA damage, oxidative stress, and hepato- and neurotoxicity by Piper longum extract in rats: The role of γH2AX and 8-OHdG

Background: The identification of genoprotectants is a promising strategy for improving human health. Piper longum has drawn scientific attention because of its diverse biological effects and traditional utilization. The current investigation aims to evaluate the genome-stabilizing potential of Piper longum against cyclophosphamide-associated genotoxicity.

Methods: We adopted a funnel screening with a three-tier evaluation approach, where Piper longum was investigated in an acellular medium, peripheral blood lymphocytes, and a rodent model. The genoprotective action of the Piper longum extract was initially performed with plasmid pBluescript SK(-) DNA. Furthermore, the extract and various fractions were screened against cyclophosphamide-induced genotoxicity using a cytokinesis-block micronucleus assay and a chromosomal aberration assay in human peripheral blood lymphocytes. The genome-stabilizing action of the extract and potent (hexane) fraction was further confirmed in vivo in Wistar albino rats by evaluating them using mammalian erythrocyte micronucleus tests, DNA fragmentation, oxidative stress markers, 8-hydroxy-2-deoxyguanosine (8-OHdG), γH2AX, and histopathological lesions in the liver and hippocampus. Additionally, acute and sub-acute toxicity studies were conducted following the Organization for Economic Co-operation and Development (OECD) guidelines for rats. Furthermore, the extract was quantified and characterized by high-performance thin-layer chromatography (HPTLC), ultra-high performance liquid chromatography–mass spectroscopy (UPLC-MS), and gas chromatography–mass spectrometry (GC-MS).

Results: The Piper longum ethanol extract was shown to protect plasmid pBluescript SK(-) DNA against H2O2-induced strand breaks. In human lymphocytes, the extract and hexane fraction showed a reduction in micronucleus formation (p &lt; 0.001) and chromosomal aberrations (p &lt; 0.01) against cyclophosphamide. Furthermore, the extract and fraction treatment, when administered at 200 mg/kg for 28 days in Wistar rats, restored cyclophosphamide-induced genomic instability by reducing micronucleus formation and DNA fragmentation; restoring redox homeostasis; decreasing 8-OHdG, a hallmark of oxidative DNA damage; reducing γH2AX, a DNA double-strand break (DSB) marker; and preserving the liver and hippocampus against histopathological lesions. The extract and fraction revealed no signs of systemic toxicity at the used doses. Piperine and piperlongumine are the major alkaloids quantified along with the presence of flavonoids in the ethanol extract and the presence of fatty acids and terpenoids in the hexane fraction of Piper longum.

Conclusion: Our investigation confirms the genoprotective action of Piper longum by reducing cyclophosphamide-associated cytogenotoxicity, oxidative stress, hepato- and neurotoxicity, oxidative DNA damage, and DNA double-strand breaks. The outcomes are critical for mitigating the genotoxic effects of chemotherapy recipients, requiring further attention.

Combined Inhibition of Smoothened and the DNA Damage Checkpoint WEE1 Exerts Antitumor Activity in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is characterized by resistance to chemotherapy and a poor prognosis. Therefore, treatments that can effectively suppress tumor growth are urgently needed. Aberrant activation of hedgehog (HH) signaling has been implicated in several cancers, including those of the hepatobiliary tract. However, the role of HH signaling in intrahepatic CCA (iCCA) has not been completely elucidated. In this study, we addressed the function of the main transducer Smoothened (SMO) and the transcription factors (TFs) GLI1 and GLI2 in iCCA. In addition, we evaluated the potential benefits of the combined inhibition of SMO and the DNA damage kinase WEE1. Transcriptomic analysis of 152 human iCCA samples showed increased expression of GLI1, GLI2, and Patched 1 (PTCH1) in tumor tissues compared with nontumor tissues. Genetic silencing of SMO, GLI1, and GLI2 inhibited the growth, survival, invasiveness, and self-renewal of iCCA cells. Pharmacologic inhibition of SMO reduced iCCA growth and viability in vitro, by inducing double-strand break DNA damage, leading to mitotic arrest and apoptotic cell death. Importantly, SMO inhibition resulted in the activation of the G2-M checkpoint and DNA damage kinase WEE1, increasing the vulnerability to WEE1 inhibition. Hence, the combination of MRT-92 with the WEE1 inhibitor AZD-1775 showed increased antitumor activity in vitro and in iCCA xenografts compared with single treatments. These data indicate that combined inhibition of SMO and WEE1 reduces tumor burden and may represent a strategy for the clinical development of novel therapeutic approaches in iCCA.

Genotoxicity of Novel Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine Sulfonamides in Normal and Cancer Cells In Vitro

Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides constitute a novel group of heterocyclic compounds with broad biological activities including anticancer properties. The compounds investigated in this study (MM134, -6, -7, and 9) were found to have antiproliferative activity against BxPC-3 and PC-3 cancer cell lines in micromolar concentrations (IC₅₀ 0.11-0.33 µM). Here, we studied the genotoxic potential of the tested compounds with alkaline and neutral comet assays, accompanied by immunocytochemical detection of phosphorylated γH2AX. We found that pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides induce significant levels of DNA damage in BxPC-3 and PC-3 cells without causing genotoxic effects in normal human lung fibroblasts (WI-38) when used in their respective IC₅₀ concentrations (except for MM134) and showed a dose-dependent increase in DNA damage following 24 h incubation of tested cancer cells with these agents. Furthermore, the influence of MM compounds on DNA damage response (DDR) factors was assessed using molecular docking and molecular dynamics simulation.

Computer-aided identification, synthesis, and biological evaluation of DNA polymerase η inhibitors for the treatment of cancer

In cancer cells, Pol η allows DNA replication and cell proliferation even in the presence of chemotherapeutic drug-induced damages, like in the case of platinum-containing drugs. Inhibition of Pol η thus represents a promising strategy to overcome drug resistance and preserve the effectiveness of chemotherapeutic drugs. Here, we report the discovery of a novel class of Pol ƞ inhibitors, with 35 active close analogs. Compound 21 (ARN24964) stands out as the best inhibitor, with an IC₅₀ value of 14.7 μM against Pol η and a good antiproliferative activity when used in combination with cisplatin - with a synergistic effect in three different cancer cell lines (A375, A549, OVCAR3). Moreover, it is characterized by a favorable drug-like profile in terms of its aqueous kinetic solubility, plasma and metabolic stability. Thus, ARN24964 is a promising compound for further structure-based drug design efforts toward developing drugs to solve or limit the issue of drug resistance to platinum-containing drugs in cancer patients.

Study on the Use of Ozone Water as a Chemical Decontamination Agent for Antineoplastic Drugs in Clinical Settings

The exposure of healthcare workers to antineoplastic drugs in hospitals has been recognized to be harmful. To minimize the risk of exposure, the removal of these drugs from work environments, such as compounding facilities, has been recommended. In our previous paper, the degradation and inactivation efficacy of ozone water, which is being introduced into Japanese hospitals as a chemical decontamination agent, was reported for its effects on typical antineoplastic drugs (gemcitabine, irinotecan, paclitaxel). This article aims to further investigate the efficacy of ozone water for eight antineoplastic drugs to clarify its application limitations. A small amount (medicinal ingredient: typically ca. 1.5 μmol) of formulation containing 5-fluorouracil, pemetrexed, cisplatin, oxaliplatin, cyclophosphamide, ifosfamide, doxorubicin, or docetaxel was mixed with 50 mL of ozone water (~8 mg/L), and the resulting solutions were analyzed by high-performance liquid chromatography over time to observe the degradation. Consequently, the ozonation was overall effective for the degradation of the drugs, however this varied depending on the chemical structures of the drugs and additives in their formulations. In addition, after the parent drugs were completely degraded by the ozonation, the degradation mixtures were subjected to 1H nuclear magnetic resonance spectroscopy and evaluated for mutagenicity against Salmonella typhimurium strains and cytotoxicity against human cancer cells. The degradation mixtures of cisplatin and ifosfamide were mutagenic while those of the other drugs were non-mutagenic. Further, the ozonation resulted in clear decreases of cytotoxicity for 5-fluorouracil, oxaliplatin, and doxorubicin, but increases of cytotoxicity for pemetrexed, cisplatin, cyclophosphamide, and ifosfamide. These results suggest that the ozone water should be restrictedly used according to the situation of contamination in clinical settings because the ozonation enhances toxicity depending on the drug even if degradation is achieved.

Cancer occurrence after SLE: effects of medication-related factors, disease-related factors and survival from an observational study

OBJECTIVES

To explore the survival and risk factors for cancer occurrence after SLE (SLE-CA).

METHODS

Patients with cancer diagnosed after SLE in Peking Union Medical College Hospital between January 2006 and September 2017 were recruited and followed. Data regarding medication-related and disease-related factors and survival were collected and compared with matched controls. Logistic regressions were applied to identify risk factors. The Kaplan-Meier method with a log-rank test was performed to evaluate survival.

RESULTS

Forty-five SLE-CA patients and 128 controls were included, with the most common cancer site being the female genital system. SLE-CA patients were exposed to a higher cumulative dosage of CYC, with less mucocutaneous and haematologic involvement and higher anti-dsDNA positivity. At the time of cancer diagnosis, SLE-CA patients had lower SLEDAI 2000 (SLEDAI-2K), tended to achieve Definitions of Remission in SLE remission and minimal disease activity, but had higher SLICC/ACR Damage Index. Multivariable analysis identified high dosage of CYC [odds ratio (OR) 1.027, 95% CI 1.008, 1.046; P = 0.005] and low SLEDAI-2K at cancer diagnosis (OR 0.756, 95% CI 0.579, 0.986; P = 0.039) as risk factors. Mucocutaneous (OR 0.330, 95% CI 0.110, 0.991; P = 0.048) and haematologic involvement (OR 0.304, 95% CI 0.103, 0.902; P = 0.032) were negatively associated with cancer occurrence after SLE. The 5- and 10-year survival rates in SLE-CA patients were 95.2% and 92.1%, respectively. No significant difference of survival was observed between SLE-CA patients and controls (P = 0.177).

CONCLUSION

High dosage of CYC and disease-related factors (low SLEDAI-2K, less mucocutaneous and haematologic involvement) were related factors for cancer occurrence after SLE, while no survival difference was observed.

Genotoxicity and apoptotic effect of silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine on malignant melanoma cells, SK-MEL-28

Complexes of coinage metals can potentially be used as alternatives to platinum-based chemotherapeutic drugs. Silver is a coinage metal that can potentially improve the spectrum of efficacy in various cancers treatment, such as malignant melanoma. Melanoma is the most aggressive form of skin cancer that is often diagnosed in young and middle-aged adults. Silver has high reactivity with skin proteins and can be developed as a malignant melanoma treatment modality. Therefore, this study aims to identify the anti-proliferative and genotoxic effects of silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine ligands in the human melanoma SK-MEL-28 cell line. The anti-proliferative effects of a series of silver(I) complex compounds labelled as OHBT, DOHBT, BrOHBT, OHMBT, and BrOHMBT were evaluated on SK-MEL-28 cells by using the Sulforhodamine B assay. Then, DNA damage analysis was performed in a time-dependent manner (30 min, 1 h and 4 h) by using alkaline comet assay to investigate the genotoxicity of OHBT and BrOHMBT at their respective IC₅₀ values. The mode of cell death was studied using Annexin V-FITC/PI flow cytometry assay. Our current findings demonstrated that all silver(I) complex compounds showed good anti-proliferative activity. The IC₅₀ values of OHBT, DOHBT, BrOHBT, OHMBT, and BrOHMBT were 2.38 ± 0.3 μM, 2.70 ± 0.17 μM, 1.34 ± 0.22 μM, 2.82 ± 0.45 μM, and 0.64 ± 0.04 μM respectively. Then, DNA damage analysis showed that OHBT and BrOHMBT could induce DNA strand breaks in a time-dependent manner, with OHBT being more prominent than BrOHMBT. This effect was accompanied by apoptosis induction in SK-MEL-28, as evaluated using Annexin V-FITC/PI assay. In conclusion, silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine exerted anti-proliferative activities by inhibiting cancer cell growth, inducing significant DNA damage and ultimately resulting in apoptosis.

Ultrastructural and Morphological Effects in T-Lymphoblastic Leukemia CEM-SS Cells Following Treatment with Nordamnacanthal and Damnacanthal from Roots of Morinda elliptica

Background: Morinda elliptica (family Rubiaceae), locally known as ‘mengkudu kecil’, has been used by the Malays for medicinal purposes. Anthraquinones isolated from the roots of Morinda elliptica, namely nordamnacanthal and damnacanthal, have been widely reported to exhibit anticancer and antioxidant properties in various cancer models in vitro and in vivo. Aim: This study analyzed the morphological and ultrastructural effects of damnacanthal and nordamnacanthal on T-lymphoblastic leukemia CEM-SS cells. Method: Light microscopy, Giemsa staining, Wright’s staining, scanning electron microscopy, and transmission electron microscopy were carried out to determine apoptosis, necrosis, and ultrastructural changes that occurred within the cells. Results: The outcomes showed that these compounds induced cell death by apoptosis and necrosis, specifically at higher doses of 10 and 30 μg/mL. Condensation and fragmentation of the nuclear chromatin, which further separated into small, membrane-bound vesicles known as apoptotic bodies, were observed in the nuclei and cytoplasm. The plasma membranes and cytoskeletons also showed marked morphological changes upon treatment with damnacanthal and nordamnacanthal, indicating apoptosis. Conclusion: Therefore, we report that damnacanthal and nordamnacanthal exhibit anticancer properties by inducing apoptosis and necrosis in CEM-SS cells, and they have potential as a drug for the treatment of T-lymphoblastic leukemia.

Effects of folate-conjugated Fe2O3@Au core-shell nanoparticles on oxidative stress markers, DNA damage, and histopathological characteristics: evidence from in vitro and in vivo studies

The aim of this work was to assess the cytotoxicity, genotoxicity, and histopathological effects of Fe2O3@Au-FA NPs using in vitro and in vivo models. Cytotoxicity and cellular uptake of nanoparticles (NPs) by HUVECs were examined via 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and inductively coupled plasma-mass-spectrometry (ICP-MS). This safe dose was then used for cytotoxicity assays, including total protein, total antioxidant capacity, lipid peroxidation, cell membrane integrity, reactive oxygen species, enzyme activity, and DNA damage. In the animal model, 32 Wistar rats were randomly categorized into 4 groups and received intraperitoneal injections of NPs. Blood samples for biochemical properties and histopathological changes were investigated. MTT results indicated 20 μg/ml as the safe dose for NPs. According to ICP-MS, treated cells showed significantly higher levels of the intracellular content of Fe (p < 0.001) and Au (p < 0.01) compared with the control group. In vitro tests did not show any significant cytotoxicity or genotoxicity at the safe dose of NPs. We found no significant elevation in intracellular γ-H2AX levels after treatment of HUVEC cells with Fe2O3@Au core-shell NPs (P > 0.05). As for the in vivo analysis, we observed no marked difference in serum biochemical parameters of rats treated with 50 mg/kg and 100 mg/kg doses of our NPs. Histopathological assessments indicated that liver, kidney, and testis tissues were not significantly affected at 50 mg/kg (liver), 50 mg/kg, and 100 mg/kg (kidney and testis) on NPs administration. These findings imply that the nanotoxicity of Fe2O3@Au-FA NPs in HUVECs and animals depends largely on the administrated dose. Our study suggests that Fe2O3@Au-FA NPs at a safe dose could be considered as new candidates in nanobiomedicine.

Updated Understanding of the Causes of Cancer, and a New Theoretical Perspective of Combinational Cancer Therapies, a Hypothesis

We present an integrative understanding of cancer as a metabolic multifactorial, multistage disease. We focus on underlying genetics-environmental interactions, evidenced by telomere changes. A range of genetic and epigenetic factors, including physical agents and predisposing factors such as diet and lifestyle are included. We present a structured model of the causes of cancer, methods of investigations, approaches to cancer prevention, and polypharmaceutical multidisciplinary complex treatment within a framework of personalized medicine. We searched PubMed, National Cancer Institute online, and other databases for publications regarding causes of cancer, reports of novel mitochondrial reprogramming, epigenetic, and telomerase therapies and state-of-the-art investigations. We focused on multistep treatment protocols to enhance early detection of cancer, and elimination or neutralization of the causes and factors associated with cancer formation and progression.Our aim is to suggest a model therapeutic protocol that incorporates the patient's genome, metabolism, and immune system status; stage of tumor development; and comorbidity(ies), if any. Investigation and treatment of cancer is a challenge that requires further holistic studies that improve the quality of life and survival rates, but are most likely to aid prevention.

Metnase and EEPD1: DNA Repair Functions and Potential Targets in Cancer Therapy

Cells respond to DNA damage by activating signaling and DNA repair systems, described as the DNA damage response (DDR). Clarifying DDR pathways and their dysregulation in cancer are important for understanding cancer etiology, how cancer cells exploit the DDR to survive endogenous and treatment-related stress, and to identify DDR targets as therapeutic targets. Cancer is often treated with genotoxic chemicals and/or ionizing radiation. These agents are cytotoxic because they induce DNA double-strand breaks (DSBs) directly, or indirectly by inducing replication stress which causes replication fork collapse to DSBs. EEPD1 and Metnase are structure-specific nucleases, and Metnase is also a protein methyl transferase that methylates histone H3 and itself. EEPD1 and Metnase promote repair of frank, two-ended DSBs, and both promote the timely and accurate restart of replication forks that have collapsed to single-ended DSBs. In addition to its roles in HR, Metnase also promotes DSB repair by classical non-homologous recombination, and chromosome decatenation mediated by TopoIIα. Although mutations in Metnase and EEPD1 are not common in cancer, both proteins are frequently overexpressed, which may help tumor cells manage oncogenic stress or confer resistance to therapeutics. Here we focus on Metnase and EEPD1 DNA repair pathways, and discuss opportunities for targeting these pathways to enhance cancer therapy.

Inhibition of EZH2 transactivation function sensitizes solid tumors to genotoxic stress

Drugs that block the activity of the methyltransferase EZH2 are in clinical development for the treatment of non-Hodgkin lymphomas harboring EZH2 gain-of-function mutations that enhance its polycomb repressive function. We have previously reported that EZH2 can act as a transcriptional activator in castration-resistant prostate cancer (CRPC). Now we show that EZH2 inhibitors can also block the transactivation activity of EZH2 and inhibit the growth of CRPC cells. Gene expression and epigenomics profiling of cells treated with EZH2 inhibitors demonstrated that in addition to derepressing gene expression, these compounds also robustly down-regulate a set of DNA damage repair (DDR) genes, especially those involved in the base excision repair (BER) pathway. Methylation of the pioneer factor FOXA1 by EZH2 contributes to the activation of these genes, and interaction with the transcriptional coactivator P300 via the transactivation domain on EZH2 directly turns on the transcription. In addition, CRISPR-Cas9-mediated knockout screens in the presence of EZH2 inhibitors identified these BER genes as the determinants that underlie the growth-inhibitory effect of EZH2 inhibitors. Interrogation of public data from diverse types of solid tumors expressing wild-type EZH2 demonstrated that expression of DDR genes is significantly correlated with EZH2 dependency and cellular sensitivity to EZH2 inhibitors. Consistent with these findings, treatment of CRPC cells with EZH2 inhibitors dramatically enhances their sensitivity to genotoxic stress. These studies reveal a previously unappreciated mechanism of action of EZH2 inhibitors and provide a mechanistic basis for potential combination cancer therapies.

HPV-induced cancers: preclinical therapeutic advancements

INTRODUCTION

High-risk HPV infections are related to several epithelial cancers. Despite the availability of prophylactic vaccines, HPV infections are still responsible for about 5% of all human malignancies worldwide. While therapeutic vaccines are ongoing clinical trials, genotoxic agents and surgical interventions represent current clinical treatments, with no specific anti-HPV drugs yet available in the clinics.

AREAS COVERED

We offer a comprehensive report of small molecules in preclinical studies proposed as potential anticancer agents against HPV-driven tumors. Given the importance of HPV oncoproteins for cancer maintenance, particularly E6 and E7, we present a classification of both non-targeted and targeted agents, with a further subdivision of the latter into two categories according to their either direct or indirect activity against viral protein functions.

EXPERT OPINION

Prophylactic vaccines can prevent the insurgence of HPV-related cancers, but have no effect against pre-existing infections. Moreover, their high cost, genotype-restricted effect and the growing worldwide distrust for vaccines make the availability of a specific drug an unmet medical need. Different viral early proteins emerge as ideal candidates for drug development. We highlight the most promising strategies and address future challenges in this field to herald the prospect of a specific therapeutic regimen against HPV-related cancers.

MicroRNAs in Pancreatic Cancer and Chemoresistance

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading malignancies affecting human health, largely because of the development of resistance to chemotherapy/radiotherapy. There are many mechanisms that mediate the development of drug resistance, such as the transport of antineoplastic agents into cells, shifts in energy metabolism and environment, antineoplastic agent-induced DNA damage, and genetic mutations. MicroRNAs are short, noncoding RNAs that are 20 to 24 nucleotides in length and serve several biological functions. They bind to the 3'-untranslated regions of target genes and induce target degradation or translational inhibition. MicroRNAs can regulate several target genes and mediate PDAC chemotherapy/radiotherapy resistance. The detection of novel microRNAs would not only reveal the molecular mechanisms of PDAC and resistance to chemotherapy/radiotherapy but also provide new approaches to PDAC therapy. MicroRNAs are thus potential therapeutic targets for PDAC and might be essential in uncovering new mechanisms of the disease.

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

DNA is intrinsically dynamic and folds transiently into alternative higher-order structures such as G-quadruplexes (G4s) and three-way DNA junctions (TWJs). G4s and TWJs can be stabilised by small molecules (ligands) that have high chemotherapeutic potential, either as standalone DNA damaging agents or combined in synthetic lethality strategies. While previous approaches have claimed to use ligands that specifically target either G4s or TWJs, we report here on a new approach in which ligands targeting both TWJs and G4s in vitro demonstrate cellular effects distinct from that of G4 ligands, and attributable to TWJ targeting. The DNA binding modes of these new, dual TWJ-/G4-ligands were studied by a panel of in vitro methods and theoretical simulations, and their cellular properties by extensive cell-based assays. We show here that cytotoxic activity of TWJ-/G4-ligands is mitigated by the DNA damage response (DDR) and DNA topoisomerase 2 (TOP2), making them different from typical G4-ligands, and implying a pivotal role of TWJs in cells. We designed and used a clickable ligand, TrisNP-α, to provide unique insights into the TWJ landscape in cells and its modulation upon co-treatments. This wealth of data was exploited to design an efficient synthetic lethality strategy combining dual ligands with clinically relevant DDR inhibitors.

In silico, in vitro, and ex vivo studies of the toxicological and pharmacological properties of the flavonoid 5,7-dihydroxy-3,8,4'-trimethoxy

Phytochemical studies of the species Pavonia glazioviana were performed. Quercetin, kaempferol, acacetin, and trimethoxylated flavonoid compounds (which present biological activity) were isolated. We aimed to evaluate the in silico, in vitro, and ex vivo toxicity of flavonoid 5,7-dihydroxy-3,8,4'-trimethoxy (Pg-1) obtained from P. glazioviana through chemical structure analyses, toxicity assessment, and predictive bioactive properties, using human samples in in vitro tests. In silico analysis suggested that Pg-1 presents a good absorption index for penetrating biological membranes (for oral bioavailability), while also suggesting potential antimutagenic, anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic, and apoptosis agonist bioactivities. Assessment of hemolytic and genotoxic effects revealed low hemolysis rates in red blood cells with no cellular toxicity in oral mucosa cells. The reduced cytotoxic activity suggested the safety of the concentrations used (500-1000 µg/mL), and demonstrated the varied interactions of Pg-1 with the analyzed cells. The data obtained in the present study suggested potential therapeutic application, and the non-toxic profile indicated viability for future studies.

Determination of O6-Methylguanine in dried blood spot of breast cancer patients after cyclophosphamide administration

Cyclophosphamide is a nitrogen mustard class of drugs that are often used in cancer chemotherapy. However, the use of Cyclophosphamide in high doses over a long period has been shown to increase the risk of developing secondary cancer. This can be indicated by the formation of mutagenic DNA adducts, such as O⁶-Methylguanine. Therefore, this adduct can be used as a biomarker for secondary cancer in patients receiving Cyclophosphamide. Bio sampling was carried out by using the Dried Blood Spot (DBS) method, followed by DNA extraction by using QIAamp DNA mini kit, and acid hydrolysis to obtain O⁶-Methylguanine. Analysis of O⁶-Methylguanine was performed by using the UPLC-MS/MS instrument with the conditions developed by Vianney, Harahap, & Suryadi (2021). Partial validation was carried out before the analysis. The results obtained from the calibration curve, accuracy, and precision validation test met the FDA requirements. The analysis method was then implemented in 16 breast cancer patients who received the Cyclophosphamide regimen. The O⁶-Methylguanine was successfully detected and quantified in all of the samples in the range of 0.55–6.66 ng/mL. It shows that the O⁶-Methylguanine accumulation in cancer patients receiving Cyclophosphamide is very likely to occur and the analysis method proposed by Vianney, Harahap, & Suryadi (2021) is potential to be used for Therapeutic Drug Monitoring in this group of patients.

Detecting Attomolar DNA-Damaging Anticancer Drug Activity in Cell Lysates with Electrochemical DNA Devices

Here, we utilize electrochemical DNA devices to quantify and understand the cancer-specific DNA-damaging activity of an emerging drug in cellular lysates at femtomolar and attomolar concentrations. Isobutyl-deoxynyboquinone (IB-DNQ), a potent and tumor-selective NAD(P)H quinone oxidoreductase 1 (NQO1) bioactivatable drug, was prepared and biochemically verified in cancer cells highly expressing NQO1 (NQO1+) and knockdowns with low NQO1 expression (NQO1-) by Western blot, NQO1 activity analysis, survival assays, oxygen consumption rate, extracellular acidification rate, and peroxide production. Lysates from these cells and the IB-DNQ drug were then introduced to a chip system bearing an array of DNA-modified electrodes, and their DNA-damaging activity was quantified by changes in DNA-mediated electrochemistry arising from base-excision repair. Device-level controls of NQO1 activity and kinetic analysis were used to verify and further understand the IB-DNQ activity. A 380 aM IB-DNQ limit of detection and a 1.3 fM midpoint of damage were observed in NQO1+ lysates, both metrics 2 orders of magnitude lower than NQO1- lysates, indicating the high IB-DNQ potency and selectivity for NQO1+ cancers. The device-level damage midpoint concentration in NQO1+ lysates was over 8 orders of magnitude lower than cell survival benchmarks, likely due to poor IB-DNQ cellular uptake, demonstrating that these devices can identify promising drugs requiring improved cell permeability. Ultimately, these results indicate the noteworthy potency and selectivity of IB-DNQ and the high sensitivity and precision of electrochemical DNA devices to analyze agents/drugs involved in DNA-damaging chemotherapies.

Complete response to neoadjuvant chemoradiotherapy in rectal cancer is associated with RAS/AKT mutations and high tumour mutational burden

BACKGROUND

Pathological complete response (pathCR) in rectal cancer is beneficial, as up to 75% of patients do not experience regrowth of the primary tumour, but it is poorly understood. We hypothesised that the changes seen in the pre-treatment biopsies of pathCR but not seen in residual tumour after chemoradiotherapy were the determinants of responsiveness.

METHODS

Two groups of patients with either complete response (pathCR group, N = 24) or no response (poor response group, N = 24) were retrieved. Pre-treatment biopsies of cancers from these patients underwent high read depth amplicon sequencing for a targeted panel, exome sequencing, methylation profiling and immunohistochemistry for DNA repair pathway proteins.

RESULTS

Twenty four patients who underwent pathCR and twenty-four who underwent poor response underwent molecular characterisation. Patients in the pathCR group had significantly higher tumour mutational burden and neoantigen load, frequent copy number alterations but fewer structural variants and enrichment for driver mutations in the PI3K/AKT/mTOR signalling pathway. There were no significant differences in tumour heterogeneity as measured by MATH score. Methylation analysis demonstrated enrichment for hypomethyation in the PI3K/AKT/mTOR signalling pathway.

DISCUSSION

The phenomenon of pathCR in rectal cancer may be related to immunovisibility caused by a high tumour mutational burden phenotype. Potential therapy resistance mechanisms involve the PI3K/AKT/mTOR signalling pathway, but tumour heterogeneity does not seem to play a role in resistance.

Analysis of the toxicological and pharmacokinetic profile of Kaempferol-3-O-β-D-(6"-E-p-coumaryl) glucopyranoside - Tiliroside: in silico, in vitro and ex vivo assay

Tiliroside is a glycosidic flavonoid present in many plants species including Helicteres velutina K. Schum (Malvaceae sensu lato), commonly known in Brazil as "pitó". This molecule has been shown to have many biological activities, however no study has been carried out to investigate the toxicity of this substance. The present work aimed to evaluate the possible cellular toxicity in silico, in vitro and ex-vivo of the kaempferol-3-O-β-D-(6"-E-p-coumaroyl) glucopyranoside (tiliroside), through chemical structure analysis, toxicity assessment and predictive bioactive properties, using human samples for in vitro and ex-vivo tests. The in silico analysis suggests that tiliroside exhibited great absorption index when penetrating biological membranes. In addition, it also displayed considerable potential for cellular protection against free radicals, and anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and antithrombotic activities. The assessment of the hemolytic and genotoxic effects of tiliroside showed low hemolysis rates in red blood cells and absence of cellular toxicity in the oral mucosa cells. The data obtained indicate that this molecule could be a promising therapeutic approach as a possible new drug with biotechnological potential.

Shining light on single-strand lesions caused by the chemotherapy drug bleomycin

Quantification of the DNA damage induced by chemotherapy in patient cells may aid in personalization of the dose used. However, assays to evaluate individual patient response to chemotherapy are not available today. Here, we present an assay that quantifies single-stranded lesions caused by the chemotherapeutic drug Bleomycin (BLM) in peripheral blood mononuclear cells (PBMCs) isolated from healthy individuals. We use base excision repair (BER) enzymes to process the DNA damage induced by BLM and then extend the processed sites with fluorescent nucleotides using a DNA polymerase. The fluorescent patches are quantified on single DNA molecules using fluorescence microscopy. Using the assay, we observe a significant variation in the in vitro induced BLM damage and its repair for different individuals. Treatment of the cells with the BER inhibitor CRT0044876 leads to a lower level of repair of BLM-induced damage, indicating the ability of the assay to detect a compromised DNA repair in patients. Overall, the data suggest that our assay could be used to sensitively detect the variation in BLM-induced DNA damage and repair in patients and can potentially be able to aid in personalizing patient doses.

Metabolites from halophilic bacterial isolates Bacillus VITPS16 are cytotoxic against HeLa cells

The present study was aimed at evaluating the cytotoxic potential of selected halophilic bacterial metabolites. The use of the metabolomics approach in identifying the unexplored bioactive metabolites from halophilic bacterial isolate reduces time and complex experiments. In our study, we used UV/Visible spectroscopy, LC-MS/MS, and NMR to identify the metabolites present in the methanolic extract of the halophilic bacterium Bacillus VITPS16. MTT assay revealed that metabolite fractions (S1-79.61% and S2-85.74%) possess cytotoxic activity. Colonogenic assay confirmed the cytotoxic potential of the fractions and apoptosis assays showed that 83.37% of the cells undergo apoptosis at 10 mg/mL concentration (MF-S2). The DNA binding studies revealed the metabolite fraction interacts with DNA resulting in cytotoxicity. The study states that MF- S2 induced an antiproliferative effect that led to apoptosis through DNA binding as one of the possible pathways. The toxicity analysis using zebrafish indicated that the metabolite fractions are non-toxic even at 10 mg/mL concentration. Fraction MF-S2 is found to contain phosphoethanolamines, glycerophospholipids, sphingolipids, apocarotenoid, enigmol and its analogue, ankaflavin and flavonoid type of metabolites, which have been previously reported to have anti-cancer activity.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02724-9.

Targeting the stress support network regulated by autophagy and senescence for cancer treatment

Autophagy and cellular senescence are two potent tumor suppressive mechanisms activated by various cellular stresses, including the expression of activated oncogenes. However, emerging evidence has also indicated their pro-tumorigenic activities, strengthening the case for the complexity of tumorigenesis. More specifically, tumorigenesis is a systemic process emanating from the combined accumulation of changes in the tumor support pathways, many of which cannot cause cancer on their own but might still provide excellent therapeutic targets for cancer treatment. In this review, we discuss the dual roles of autophagy and senescence during tumorigenesis, with a specific focus on the stress support networks in cancer cells modulated by these processes. A deeper understanding of such context-dependent roles may help to enhance the effectiveness of cancer therapies targeting autophagy and senescence, while limiting their potential side effects. This will steer and accelerate the pace of research and drug development for cancer treatment.

Rhamnusalaternus Plant: Extraction of Bioactive Fractions and Evaluation of Their Pharmacological and Phytochemical Properties

Rhamnus alaternus, is a wild-growing shrub, belonging to the Rhamnaceae family. Widely distributed in the Mediterranean basin, R. alaternus is used in the usual medicine in numerous countries, mostly Tunisia, Algeria, Morocco, Spain, France, Italy, and Croatia. A large number of disorders-including dermatological complications, diabetes, hepatitis, and goiter problems-can be treated by the various parts of R. alaternus (i.e., roots, bark, berries, and leaves). Several bioactive compounds were isolated from R. alaternus, including flavonoids, anthocyanins, and anthraquinones, and showed several effects such as antioxidant, antihyperlipidemic, antigenotoxic, antimutagenic, antimicrobial, and antiproliferative. This review summarizes the updated information concerning the botanical description, distribution, extraction processes applied on R. alaternus, and its ethnopharmacology, toxicity, phytochemistry, and pharmacological effects.

Natural Killer Cells and Anti-Cancer Therapies: Reciprocal Effects on Immune Function and Therapeutic Response

Simple Summary

Natural Killer (NK) cells are innate lymphocytes that play an important role in the immune response against cancer. Their activity is controlled by a balance of inhibitory and activating receptors, which in cancer can be skewed to favor their suppression in support of immune escape. It is therefore imperative to find ways to optimize their antitumor functionality. In this review, we explore and discuss how their activity influences, or even mediates, the efficacy of various anti-cancer therapies and, vice versa, how their activity can be affected by these therapies. Knowledge of the mechanisms underlying these observations could provide rationales for combining anti-cancer treatments with strategies enhancing NK cell function in order to improve their therapeutic efficacy.

Abstract

Natural Killer (NK) cells are innate immune cells with the unique ability to recognize and kill virus-infected and cancer cells without prior immune sensitization. Due to their expression of the Fc receptor CD16, effector NK cells can kill tumor cells through antibody-dependent cytotoxicity, making them relevant players in antibody-based cancer therapies. The role of NK cells in other approved and experimental anti-cancer therapies is more elusive. Here, we review the possible role of NK cells in the efficacy of various anti-tumor therapies, including radiotherapy, chemotherapy, and immunotherapy, as well as the impact of these therapies on NK cell function.

Combined RNA/tissue profiling identifies novel Cancer/testis genes

Cancer/Testis (CT) genes are induced in germ cells, repressed in somatic cells, and derepressed in somatic tumors, where these genes can contribute to cancer progression. CT gene identification requires data obtained using standardized protocols and technologies. This is a challenge because data for germ cells, gonads, normal somatic tissues, and a wide range of cancer samples stem from multiple sources and were generated over substantial periods of time. We carried out a GeneChip‐based RNA profiling analysis using our own data for testis and enriched germ cells, data for somatic cancers from the Expression Project for Oncology, and data for normal somatic tissues from the Gene Omnibus Repository. We identified 478 candidate loci that include known CT genes, numerous genes associated with oncogenic processes, and novel candidates that are not referenced in the Cancer/Testis Database (www.cta.lncc.br). We complemented RNA expression data at the protein level for SPESP1, GALNTL5, PDCL2, and C11orf42 using cancer tissue microarrays covering malignant tumors of breast, uterus, thyroid, and kidney, as well as published RNA profiling and immunohistochemical data provided by the Human Protein Atlas (www.proteinatlas.org). We report that combined RNA/tissue profiling identifies novel CT genes that may be of clinical interest as therapeutical targets or biomarkers. Our findings also highlight the challenges of detecting truly germ cell‐specific mRNAs and the proteins they encode in highly heterogenous testicular, somatic, and tumor tissues.

A combined experimental and theoretical rationalization of an unusual zinc(ii)-mediated conversion of 18-membered Schiff-base macrocycles to 18-membered imine–amine macrocycles with imidazolidine side rings: an investigation of their bio-relevant catalytic activities

Macrocyclic Zn(ii)-based Schiff base complexes exhibit significant phosphatase-like activity as well as high potential anticancer activity against breast cancer cells.

Targeting non-canonical activation of GLI1 by the SOX2-BRD4 transcriptional complex improves the efficacy of HEDGEHOG pathway inhibition in melanoma

Despite the development of new targeted and immune therapies, the prognosis of metastatic melanoma remains bleak. Therefore, it is critical to better understand the mechanisms controlling advanced melanoma to develop more effective treatment regimens. Hedgehog/GLI (HH/GLI) signaling inhibitors targeting the central pathway transducer Smoothened (SMO) have shown to be clinical efficacious in skin cancer; however, several mechanisms of non-canonical HH/GLI pathway activation limit their efficacy. Here, we identify a novel SOX2-BRD4 transcriptional complex driving the expression of GLI1, the final effector of the HH/GLI pathway, providing a novel mechanism of non-canonical SMO-independent activation of HH/GLI signaling in melanoma. Consistently, we find a positive correlation between the expression of GLI1 and SOX2 in human melanoma samples and cell lines. Further, we show that combined targeting of canonical HH/GLI pathway with the SMO inhibitor MRT-92 and of the SOX2-BRD4 complex using a potent Proteolysis Targeted Chimeras (PROTACs)-derived BRD4 degrader (MZ1), yields a synergistic anti-proliferative effect in melanoma cells independently of their BRAF, NRAS, and NF1 mutational status, with complete abrogation of GLI1 expression. Combination of MRT-92 and MZ1 strongly potentiates the antitumor effect of either drug as single agents in an orthotopic melanoma model. Together, our data provide evidence of a novel mechanism of non-canonical activation of GLI1 by the SOX2-BRD4 transcriptional complex, and describe the efficacy of a new combinatorial treatment for a subset of melanomas with an active SOX2-BRD4-GLI1 axis.

Mitotic entry upon Topo II catalytic inhibition is controlled by Chk1 and Plk1

Catalytic inhibition of topoisomerase II during G2 phase delays onset of mitosis due to the activation of the so-called decatenation checkpoint. This checkpoint is less known compared with the extensively studied G2 DNA damage checkpoint and is partially compromised in many tumor cells. We recently identified MCPH1 as a key regulator that confers cells with the capacity to adapt to the decatenation checkpoint. In the present work, we have explored the contributions of checkpoint kinase 1 (Chk1) and polo-like kinase 1 (Plk1), in order to better understand the molecular basis of decatenation checkpoint. Our results demonstrate that Chk1 function is required to sustain the G2 arrest induced by catalytic inhibition of Topo II. Interestingly, Chk1 loss of function restores adaptation in cells lacking MCPH1. Furthermore, we demonstrate that Plk1 function is required to bypass the decatenation checkpoint arrest in cells following Chk1 inhibition. Taken together, our data suggest that MCPH1 is critical to allow checkpoint adaptation by counteracting Chk1-mediated inactivation of Plk1. Importantly, we also provide evidence that MCPH1 function is not required to allow recovery from this checkpoint, which lends support to the notion that checkpoint adaptation and recovery are different mechanisms distinguished in part by specific effectors.