Activity of MM-398, nanoliposomal irinotecan (nal-IRI), in Ewing's family tumor xenografts is associated with high exposure of tumor to drug and high SLFN11 expression

Improved anti-breast cancer activity by doxorubicin-loaded super stealth liposomes

PEGylation is currently used for the synthesis of stealth liposomes and to enhance the pharmacokinetic and biopharmaceutical properties of payloads. PEGylated dendron phospholipids can decrease the detachment of polyethylene glycol (PEG) from the liposomal surface owing to an increased hydrophobic anchoring effect on the phospholipid bilayer of liposomes and thus generating super stealth liposomes that are suitable for the systemic delivery of anticancer drugs. Herein, doxorubicin hydrochloride-loaded super stealth liposomes were studied for the treatment of breast cancer lung metastasis in an animal model. The results demonstrated that the super stealth liposomes had suitable physicochemical properties for in vivo administration and could significantly increase the efficacy of doxorubicin in breast cancer lung metastasis tumor-bearing mice compared to the free drug. The super stealth liposomes also increased doxorubicin accumulation inside the tumor tissue. The permanence of PEG on the surface of the super stealth liposomes favored the formation of a depot of therapeutic nanocarriers inside the tumor tissue by improving their permanence after stopping treatment. The doxorubicin-loaded super stealth liposomes increased the survival of the mouse tumor model. These promising results demonstrate that the doxorubicin-loaded super stealth liposomes could be an effective nanomedicine to treat metastatic breast cancer.

Recent advances in liposome-based targeted cancer therapy

Nano-drug delivery systems have opened new pathways for tumor treatment by overcoming some of the limitations of conventional drugs, such as physiological degradation, short half-life, and rapid release. Liposomes are promising nanocarrier systems due to their biocompatibility, low toxicity, and high inclusivity, as well as their enhanced drug bioavailability. Various strategies for active targeting of liposomal formulations have been investigated to achieve the highest drug efficacy. This review aims to summarize current developments in novel liposomal formulations, particularly ligand-targeted liposomes (such as folate, transferrin, hyaluronic acid, antibodies, aptamer, and peptide, etc.) used for the therapy of various cancers and provide an insight on the challenges and future of liposomes for scientists and pharmaceutical companies.

Revitalizing Cancer Treatment: Exploring the Role of Drug Repurposing

Cancer persists as a global challenge necessitating continual innovation in treatment strategies. Despite significant advancements in comprehending the disease, cancer remains a leading cause of mortality worldwide, exerting substantial economic burdens on healthcare systems and societies. The emergence of drug resistance further complicates therapeutic efficacy, underscoring the urgent need for alternative approaches. Drug repurposing, characterized by the utilization of existing drugs for novel clinical applications, emerges as a promising avenue for addressing these challenges. Repurposed drugs, comprising FDA-approved (in other disease indications), generic, off-patent, and failed medications, offer distinct advantages including established safety profiles, cost-effectiveness, and expedited development timelines compared to novel drug discovery processes. Various methodologies, such as knowledge-based analyses, drug-centric strategies, and computational approaches, play pivotal roles in identifying potential candidates for repurposing. However, despite the promise of repurposed drugs, drug repositioning confronts formidable obstacles. Patenting issues, financial constraints associated with conducting extensive clinical trials, and the necessity for combination therapies to overcome the limitations of monotherapy pose significant challenges. This review provides an in-depth exploration of drug repurposing, covering a diverse array of approaches including experimental, re-engineering protein, nanotechnology, and computational methods. Each of these avenues presents distinct opportunities and obstacles in the pursuit of identifying novel clinical uses for established drugs. By examining the multifaceted landscape of drug repurposing, this review aims to offer comprehensive insights into its potential to transform cancer therapeutics.

Quantification of Unencapsulated Drug in Target Tissues Demonstrates Pharmacological Properties and Therapeutic Effects of Liposomal Topotecan (FF-10850)

PURPOSE

Quantifying unencapsulated drug concentrations in tissues is crucial for understanding the mechanisms underlying the efficacy and safety of liposomal drugs; however, the methodology for this has not been fully established. Herein, we aimed to investigate the enhanced therapeutic potential of a pegylated liposomal formulation of topotecan (FF-10850) by analyzing the concentrations of the unencapsulated drug in target tissues, to guide the improvement of its dosing regimen.

METHODS

We developed a method for measuring unencapsulated topotecan concentrations in tumor and bone marrow interstitial fluid (BM-ISF) and applied this method to pharmacokinetic assessments. The ratios of the area under the concentration-time curves (AUCs) between tumor and BM-ISF were calculated for total and unencapsulated topotecan. DNA damage and antitumor effects of FF-10850 or non-liposomal topotecan (TPT) were evaluated in an ES-2 mice xenograft model.

RESULTS

FF-10850 exhibited a much larger AUC ratio between tumor and BM-ISF for unencapsulated topotecan (2.96), but not for total topotecan (0.752), than TPT (0.833). FF-10850 promoted milder DNA damage in the bone marrow than TPT; however, FF-10850 and TPT elicited comparable DNA damage in the tumor. These findings highlight the greater tumor exposure to unencapsulated topotecan and lower bone marrow exposure to FF-10850 than TPT. The dosing regimen was successfully improved based on the kinetics of unencapsulated topotecan and DNA damage.

CONCLUSIONS

Tissue pharmacokinetics of unencapsulated topotecan elucidated the favorable pharmacological properties of FF-10850. Evaluation of tissue exposure to an unencapsulated drug with appropriate pharmacodynamic markers can be valuable in optimizing liposomal drugs and dosing regimens.

Unleashing the Potential of Camptothecin: Exploring Innovative Strategies for Structural Modification and Therapeutic Advancements

Camptothecin (CPT) is a potent anti-cancer agent targeting topoisomerase I (TOP1). However, CPT has poor pharmacokinetic properties, causes toxicities, and leads to drug resistance, which limit its clinical use. In this paper, to review the current state of CPT research. We first briefly explain CPT's TOP1 inhibition mechanism and the key hurdles in CPT drug development. Then we examine strategies to overcome CPT's limitations through structural modifications and advanced delivery systems. Though modifications alone seem insufficient to fully enhance CPT's therapeutic potential, structure-activity relationship analysis provides insights to guide optimization of CPT analogs. In comparison, advanced delivery systems integrating controlled release, imaging capabilities, and combination therapies via stimulus-responsive linkers and targeting moieties show great promise for improving CPT's pharmacological profile. Looking forward, multifaceted approaches combining selective CPT derivatives with advanced delivery systems, informed by emerging biological insights, hold promise for fully unleashing CPT's anti-cancer potential.

Epigenetically upregulating TROP2 and SLFN11 enhances therapeutic efficacy of TROP2 antibody drug conjugate sacitizumab govitecan

TROP2 antibody drug conjugates (ADCs) are under active development. We seek to determine whether we can enhance activity of TROP2 ADCs by increasing TROP2 expression. In metaplastic breast cancers (MpBC), there is limited expression of TROP2, and downregulating transcription factor ZEB1 upregulates E-cad and TROP2, thus sensitizing cancers to TROP2 ADC sacituzumab govitecan (SG). Demethylating agent decitabine decreases DNA methyltransferase expression and TROP2 promoter methylation and subsequently increases TROP2 expression. Decitabine treatment as well as overexpression of TROP2 significantly enhance SG antitumor activity. Decitabine also increases SLFN11, a biomarker of topoisomerase 1 inhibitor (TOP1) sensitivity and is synergistic with SG which has a TOP1 payload, in TROP2-expressing SLFN11-low BC cells. In conclusion, TROP2 and SLFN11 expression can be epigenetically modulated and the combination of demethylating agent decitabine with TROP2 ADCs may represent a novel therapeutic approach for tumors with low TROP2 or SLFN11 expression.

DNA-PKcs as an upstream mediator of OCT4-induced MYC activation in small cell lung cancer

Small cell lung cancer (SCLC) is a neuroendocrine tumor noted for the rapid development of both metastases and resistance to chemotherapy. High mutation burden, ubiquitous loss of TP53 and RB1, and a mutually exclusive amplification of MYC gene family members contribute to genomic instability and make the development of new targeted agents a challenge. Previously, we reported a novel OCT4-induced MYC transcriptional activation pathway involving c-MYC, pOCT4^S111, and MAPKAPK2 in progressive neuroblastoma, also a neuroendocrine tumor. Using tumor microarray analysis of clinical samples and preclinical models, we now report a correlation in expression between these proteins in SCLC. In correlating c-MYC protein expression with genomic amplification, we determined that some SCLC cell lines exhibited high c-MYC without genomic amplification, implying amplification-independent MYC activation. We then confirmed direct interaction between OCT4 and DNA-PKcs and identified specific OCT4 and DNA-PKcs binding sites. Knock-down of both POU5F1 (encoding OCT4) and PRKDC (encoding DNA-PKcs) resulted in decreased c-MYC expression. Further, we confirmed binding of OCT4 to the promoter/enhancer region of MYC. Together, these data establish the presence of a DNA-PKcs/OCT4/c-MYC pathway in SCLCs. We then disruptively targeted this pathway and demonstrated anticancer activity in SCLC cell lines and xenografts using both DNA-PKcs inhibitors and a protein-protein interaction inhibitor of DNA-PKcs and OCT4. In conclusion, we demonstrate here that DNA-PKcs can mediate high c-MYC expression in SCLCs, and that this pathway may represent a new therapeutic target for SCLCs with high c-MYC expression.

Role of Gut Microbiota in Breast Cancer and Drug Resistance

Breast cancer is the most common malignancy in women worldwide. The cause of cancer is multifactorial. An early diagnosis and the appropriate treatment of cancer can improve the chances of survival. Recent studies have shown that breast cancer is influenced by the microbiota. Different microbial signatures have been identified in the breast microbiota, which have different patterns depending on the stage and biological subgroups. The human digestive system contains approximately 100 trillion bacteria. The gut microbiota is an emerging field of research that is associated with specific biological processes in many diseases, including cardiovascular disease, obesity, diabetes, brain disease, rheumatoid arthritis, and cancer. In this review article, we discuss the impact of the microbiota on breast cancer, with a primary focus on the gut microbiota’s regulation of the breast cancer microenvironment. Ultimately, updates on how immunotherapy can affect the breast cancer-based microbiome and further clinical trials on the breast and microbiome axis may be an important piece of the puzzle in better predicting breast cancer risk and prognosis.

Liposomal Irinotecan Shows a Larger Therapeutic Index than Non-liposomal Irinotecan in Patient-Derived Xenograft Models of Pancreatic Cancer

INTRODUCTION

Liposomal irinotecan promotes controlled sustained release of irinotecan (CPT-11), therefore, we hypothesize that the therapeutic index (quantitative measurement of the relative efficacy/safety ratio of a drug) will be higher for liposomal than non-liposomal irinotecan.

METHODS

We compared the therapeutic indexes of liposomal and non-liposomal irinotecan in mice bearing subcutaneous patient-derived xenograft (PDX) pancreatic tumors under dosing regimens approximating the clinical setting. Following preliminary drug sensitivity/antitumor activity analyses on three PDX tumor models, one model was selected for analyses of efficacy, biomarker, toxicology, pharmacokinetics in mice receiving liposomal irinotecan (2.5, 10, 50 mg/kg/week) or non-liposomal irinotecan (10, 25, 50 mg/kg/week). The maximum tolerated dose (MTD) for each treatment was 50 mg/kg/week.

RESULTS

Using the selected IM-PAN-001 model at the MTD (both treatments, 50 mg/kg/week), antitumor activity, phospho-histone gamma-H2AX protein staining in cancer cell nuclei, histological tumor regression, and plasma levels of CPT-11 and its active metabolite SN-38 after 24 h were greater with liposomal than non-liposomal irinotecan, but tumor SN-38 levels were similar. At the lowest doses assessed, antitumor activity, histological tumor regression, and jejunum and bone marrow toxicity were similar. Based on these findings, liposomal and non-liposomal irinotecan had therapeutic indexes of 20 and 5, respectively.

CONCLUSION

This non-clinical study showed a fourfold broader therapeutic index with liposomal than non-liposomal irinotecan in mice bearing IM-PAN-001 PDX pancreatic tumors, even at optimal dosing for the two drugs. These findings support the clinical benefit observed with liposomal irinotecan in patients with pancreatic cancer.

Drug Stability and Minimized Acid-/Drug-Catalyzed Phospholipid Degradation in Liposomal Irinotecan

Therapeutics at or close to the nanoscale, such as liposomal irinotecan, offer significant promise for the treatment of solid tumors. Their potential advantage over the unencapsulated or free form of the drug is due in part to their altered biodistribution. For slow and sustained release, significant optimization of formulation is needed to achieve the required level of stability and allow long-term storage of the drug product. Gradient-based liposomal formulation of camptothecins such as irinotecan poses unique challenges owing to the camptothecin- and acid-catalyzed hydrolysis of phospholipid esters in the inner monolayer of the liposomal membrane. We demonstrated that a narrow set of conditions related to the external pH, temperature, intraliposomal concentration, identity of the drug-trapping agent, physical form of the drug inside the liposomes, and final drug load have a marked impact on the stability of the liposome phospholipid membrane. The physical form of the drug inside the liposome was shown to be an insoluble gel with an irinotecan-to-sulfate ratio approximating 1:1, reducing the potential for irinotecan-catalyzed phospholipid hydrolysis in the internal phospholipid monolayer. As a result of this work, a stable and active liposome formulation has been developed that maintains phospholipid chemical stability following long-term storage at 2-8°C.

Ewing Sarcoma Meets Epigenetics, Immunology and Nanomedicine: Moving Forward into Novel Therapeutic Strategies

Simple Summary

Ewing Sarcoma treatment is traditionally based on chemotherapy, surgery, and radiotherapy. Although these standard of care regimens are efficient at early disease stages, many patients fail to respond appropriately, which has prompted the search for more efficacious and specific treatments. A deeper understanding of the basic molecular mechanisms underlying the biology of both tumor cells and the tumor microenvironment, as well as advances in drug delivery, has led to the development of different approaches to improve the treatment in Ewing Sarcoma patients. Thus, epigenetic, and immunotherapy-based drugs, along with nanotechnology delivery strategies, represent novel preclinical and clinical studies in the treatment of Ewing Sarcoma. In this review, we provide a comprehensive overview of these emerging therapeutic strategies and summarize the potential of the latest preclinical and clinical trials in Ewing Sarcoma research. Finally, we underline the value and future directions of these new treatments.

Abstract

Ewing Sarcoma (EWS) is an aggressive bone and soft tissue tumor that mainly affects children, adolescents, and young adults. The standard therapy, including chemotherapy, surgery, and radiotherapy, has substantially improved the survival of EWS patients with localized disease. Unfortunately, this multimodal treatment remains elusive in clinics for those patients with recurrent or metastatic disease who have an unfavorable prognosis. Consistently, there is an urgent need to find new strategies for patients that fail to respond to standard therapies. In this regard, in the last decade, treatments targeting epigenetic dependencies in tumor cells and the immune system have emerged into the clinical scenario. Additionally, recent advances in nanomedicine provide novel delivery drug systems, which may address challenges such as side effects and toxicity. Therefore, therapeutic strategies stemming from epigenetics, immunology, and nanomedicine yield promising alternatives for treating these patients. In this review, we highlight the most relevant EWS preclinical and clinical studies in epigenetics, immunotherapy, and nanotherapy conducted in the last five years.

Challenging the fundamental conjectures in nanoparticle drug delivery for chemotherapy treatment of solid cancers

Nanomedicines for cancer treatment have been studied extensively over the last few decades. Yet, only five anticancer nanomedicines have received approvals from the United States Food and Drug Administration (FDA) for treating solid tumors. This drastic mismatch between effort and return calls into question the basic understanding of this field. Various viewpoints on nanomedicines have been presented regarding their potentials and inefficiencies. However, the underlying logics of nanomedicine research and its inadequate translation to the successful use in the clinic have not been thoroughly examined. Tumor-targeted drug delivery was used to understand the shortfalls of the nanomedicine field in general. The concept of tumor-targeted drug delivery by nanomedicine has been based on two conjectures: (i) increased drug delivery to tumors provides better efficacy, and (ii) decreased drug delivery to healthy organs results in fewer side effects. The clinical evidence gathered from the literature indicates that nanomedicines bearing classic chemotherapeutic drugs, such as Dox, cis-Pt, CPT and PTX, have already reached the maximum drug delivery limit to solid tumors in humans. Still, the anticancer efficacy and safety remain unchanged despite the increased tumor accumulation. Thus, it is understandable to see few nanomedicine-based formulations approved by the FDA. The examination of FDA-approved nanomedicine formulations indicates that their approvals were not based on the improved delivery to tumors but mostly on changes in dose-limiting toxicity unique to each drug. This comprehensive analysis of the fundamentals of anticancer nanomedicines is designed to provide an accurate picture of the field's underlying false conjectures, hopefully, thereby accelerating the future clinical translations of many formulations under research.

Augmenting Experimental Gastric Cancer Activity of Irinotecan through Liposomal Formulation and Antiangiogenic Combination Therapy

Gastric adenocarcinoma (GAC) is the third most common cause of cancer-related deaths worldwide. Combination chemotherapy remains the standard treatment for advanced GAC. Liposomal irinotecan (nal-IRI) has improved pharmacokinetics (PK) and drug biodistribution compared with irinotecan (IRI, CPT-11). Angiogenesis plays a crucial role in the progression and metastasis of GAC. We evaluated the antitumor efficacy of nal-IRI in combination with novel antiangiogenic agents in GAC mouse models. Animal survival studies were performed in peritoneal dissemination xenografts. Tumor growth and PK studies were performed in subcutaneous xenografts. Compared with controls, extension in animal survival by nal-IRI and IRI was >156% and >94%, respectively. The addition of nintedanib or DC101 extended nal-IRI response by 13% and 15%, and IRI response by 37% and 31% (MKN-45 xenografts); nal-IRI response by 11% and 3%, and IRI response by 16% and 40% (KATO-III xenografts). Retardation of tumor growth was greater with nal-IRI (92%) than IRI (71%). Nintedanib and DC101 addition tend to augment nal-IRI or IRI response in this model. The addition of antiangiogenic agents enhanced tumor cell proliferation inhibition effects of nal-IRI or IRI. The tumor vasculature was decreased by nintedanib (65%) and DC101 (58%), while nal-IRI and IRI alone showed no effect. PK characterization in GAC xenografts demonstrated that compared with IRI, nal-IRI treatment groups had higher retention, circulation time, and tumor levels of CPT-11 and its active metabolite SN-38. These findings indicate that nal-IRI, alone and in combination with antiangiogenic agents, has the potential for improving clinical GAC therapy.

Enzymatic drug release cascade from polymeric prodrug nanoassemblies enables targeted chemotherapy

Cancer drug delivery systems often suffer from premature drug leakage during transportation and/or inefficient drug release within cancer cells. We present here a polymeric prodrug nanoassembly that addresses these problems simultaneously. This nanoassembly comprises a polymeric prodrug with novel trivalent phenylboronate moieties for drug conjugation via ether linkages, as well as β-lapachone (Lapa). While the ether linkage enables nearly no drug release under physiological conditions, the Lapa molecules can induce the reactive oxygen species (ROS) burst specifically in cancer cells via NAD(P)H: quinone oxidoreductase-1 catalysis, which triggers the cleavage of the ether bonds and thus cascade amplification drug release in cancer cells. As a result, the nanoassemblies exhibit much higher cytotoxicity against cancer cells than normal cells, and also increased therapeutic efficacy and reduced side effects compared to the clinically used irinotecan. We anticipate that this strategy can be applied to other drug delivery platforms to enable more precise drug release.

Structural, molecular, and functional insights into Schlafen proteins

Schlafen (SLFN) genes belong to a vertebrate gene family encoding proteins with high sequence homology. However, each SLFN is functionally divergent and differentially expressed in various tissues and species, showing a wide range of expression in cancer and normal cells. SLFNs are involved in various cellular and tissue-specific processes, including DNA replication, proliferation, immune and interferon responses, viral infections, and sensitivity to DNA-targeted anticancer agents. The fundamental molecular characteristics of SLFNs and their structures are beginning to be elucidated. Here, we review recent structural insights into the N-terminal, middle and C-terminal domains (N-, M-, and C-domains, respectively) of human SLFNs and discuss the current understanding of their biological roles. We review the distinct molecular activities of SLFN11, SLFN5, and SLFN12 and the relevance of SLFN11 as a predictive biomarker in oncology.

The diverse roles that Schlafen family proteins play in cell proliferation, immune modulation, and other biological processes make them promising targets for treating and tracking diseases, especially cancer. Ukhyun Jo and Yves Pommier from the National Cancer Institute in Bethesda, USA, review the molecular characteristics and structural features of Schlafen proteins. These proteins take their name from the German word for “sleep”, as the first described Schlafen proteins caused cells to stop dividing, although later reports found that related members of the same protein family serve myriad cellular functions, including in the regulation of DNA replication. A better understanding of Schlafen proteins could open up new avenues in cancer management, for instance, diagnostics that monitor activity levels of one such protein, SLFN11, could help oncologists predict how well patients might respond to anti-cancer therapies.

Can Schlafen 11 Help to Stratify Ovarian Cancer Patients Treated with DNA-Damaging Agents?

Platinum-based chemotherapy has been the cornerstone of systemic treatment in ovarian cancer. Since no validated molecular predictive markers have been identified yet, the response to platinum-based chemotherapy has been evaluated clinically, based on platinum-free interval. The new promising marker Schlafen 11 seems to correlate with sensitivity or resistance to DNA-damaging agents, including platinum compounds or PARP inhibitors in various types of cancer. We provide background information about the function of Schlafen 11, its evaluation in tumor tissue, and its prevalence in ovarian cancer. We discuss the current evidence of the correlation of Schlafen 11 expression in ovarian cancer with treatment outcomes and the potential use of Schlafen 11 as the key predictive and prognostic marker that could help to better stratify ovarian cancer patients treated with platinum-based chemotherapy or PARP inhibitors. We also provide perspectives on future directions in the research on this promising marker.

Single-treatment tumor ablation with photodynamic liposomal irinotecan sucrosulfate

Irinotecan (IRI) loaded actively into PEGylated liposomes via a sucrosulfate gradient has been approved recently to treat advanced pancreatic cancer. In this study, a similar liposomal composition was developed that includes a low mole fraction (1 mol.%) of porphyrin-phospholipid (PoP), a photosensitizer that stably incorporates into liposomes, to confer light-triggered IRI release. IRI-loaded PoP liposomes containing ammonium sucrosulfate (ASOS) as a complexing agent were more stable in serum compared to liposomes employing the more conventional ammonium sulfate. Without irradiation, PoP IRI liposomes released less than 5% IRI during 8 h of incubation in bovine serum at 37 °C, but released over 90% of the drug within minutes of exposure to red light (665 nm) irradiation. A single treatment with IRI-PoP liposomes and light exposure (15 mg/kg IRI with 250 J/cm2) resulted in tumor eradication in mice bearing either MIA PaCa-2 tumors or low-passage patient-derived tumor xenografts that recapitulate characteristics of the clinical disease. Analogous monotherapies of IRI or photodynamic therapy were ineffective in controlling tumor growth. Enhanced drug uptake could be visualized within laser-treated tumors by direct in situ imaging of irinotecan. Biodistribution analysis of IRI, its active metabolite (SN-38), and major metabolite (SN-38 G) showed that laser treatment significantly increased tumor accumulation of all IRI-derived molecular species. A pharmacokinetic model that hypothesized tumor vasculature permeabilization as the primary reason underlying the increased drug deposition accounted for the enhanced drug influx into tumors.

Structural and biochemical characterization of human Schlafen 5

The Schlafen family belongs to the interferon-stimulated genes and its members are involved in cell cycle regulation, T cell quiescence, inhibition of viral replication, DNA-repair and tRNA processing. Here, we present the cryo-EM structure of full-length human Schlafen 5 (SLFN5) and the high-resolution crystal structure of the highly conserved N-terminal core domain. We show that the core domain does not resemble an ATPase-like fold and neither binds nor hydrolyzes ATP. SLFN5 binds tRNA as well as single- and double-stranded DNA, suggesting a potential role in transcriptional regulation. Unlike rat Slfn13 or human SLFN11, human SLFN5 did not cleave tRNA. Based on the structure, we identified two residues in proximity to the zinc finger motif that decreased DNA binding when mutated. These results indicate that Schlafen proteins have divergent enzymatic functions and provide a structural platform for future biochemical and genetic studies.

SLFN11 biomarker status predicts response to lurbinectedin as a single agent and in combination with ATR inhibition in small cell lung cancer

Background

Lurbinectedin recently received FDA accelerated approval as a second line treatment option for metastatic small cell lung cancer (SCLC). However, there are currently no established biomarkers to predict SCLC sensitivity or resistance to lurbinectedin or preclinical studies to guide rational combinations.

Methods

Drug sensitivity was assayed in proliferation assays and xenograft models. Baseline proteomic profiling was performed by reverse-phase protein array. Lurbinectedin-induced changes in intracellular signaling pathways were assayed by Western blot.

Results

Among 21 human SCLC cell lines, cytotoxicity was observed following lurbinectedin treatment at a low dose (median IC50 0.46 nM, range, 0.06–1.83 nM). Notably, cell lines with high expression of Schlafen-11 (SLFN11) protein, a promising biomarker of response to other DNA damaging agents (e.g., chemotherapy, PARP inhibitors), were more sensitive to single-agent lurbinectedin (FC =3.2, P=0.005). SLFN11 was validated as a biomarker of sensitivity to lurbinectedin using siRNA knockdown and in xenografts representing SLFN11 high and low SCLC. Replication stress and DNA damage markers (e.g., γH2AX, phosphorylated CHK1, phosphorylated RPA32) increased in SCLC cell lines following treatment with lurbinectedin. Lurbinectedin also induced PD-L1 expression via cGAS-STING pathway activation. Finally, the combination of lurbinectedin with the ataxia telangiectasia and Rad3-related protein (ATR) inhibitors ceralasertib and berzosertib showed a greater than additive effect in SLFN11-low models.

Conclusions

Together our data confirm the activity of lurbinectedin across a large cohort of SCLC models and identify SLFN11 as a top candidate biomarker for lurbinectedin sensitivity. In SLFN11-low SCLC cell lines which are relatively resistance to lurbinectedin, the addition of an ATR inhibitor to lurbinectedin re-sensitized otherwise resistant cells, confirming previous observations that SLFN11 is a master regulator of DNA damage response independent of ATR, and the absence of SLFN11 leads to synthetic lethality with ATR inhibition. This study provides a rationale for lurbinectedin in combination with ATR inhibitors to overcome resistance in SCLC with low SLFN11 expression.

A wake-up call for cancer DNA damage: the role of Schlafen 11 (SLFN11) across multiple cancers

DNA-damaging agents exploit increased genomic instability, a hallmark of cancer. Recently, inhibitors targeting the DNA damage response (DDR) pathways, such as PARP inhibitors, have also shown promising therapeutic potential. However, not all tumors respond well to these treatments, suggesting additional determinants of response are required. Schlafen 11 (SLFN11), a putative DNA/RNA helicase that induces irreversible replication block, is emerging as an important regulator of cellular response to DNA damage. Preclinical and emerging clinical trial data suggest that SLFN11 is a predictive biomarker of response to a wide range of therapeutics that cause DNA damage including platinum salts and topoisomerase I/II inhibitors, as well as PARP inhibitors, which has raised exciting possibilities for its clinical application. In this article, we review the function, prevalence, and clinical testing of SLFN11 in tumor biopsy samples and circulating tumor cells. We discuss mounting evidence of SLFN11 as a key predictive biomarker for a wide range of cancer therapeutics and as a prognostic marker across several cancer types. Furthermore, we discuss emerging areas of investigation such as epigenetic reactivation of SLFN11 and its role in activating immune response. We then provide perspectives on open questions and future directions in studying this important biomarker.

BRCAness, SLFN11, and RB1 loss predict response to topoisomerase I inhibitors in triple-negative breast cancers

Topoisomerase I (TOP1) inhibitors trap TOP1 cleavage complexes resulting in DNA double-strand breaks (DSBs) during replication, which are repaired by homologous recombination (HR). Triple-negative breast cancer (TNBC) could be eligible for TOP1 inhibitors given the considerable proportion of tumors with a defect in HR-mediated repair (BRCAness). The TOP1 inhibitor irinotecan was tested in 40 patient-derived xenografts (PDXs) of TNBC. BRCAness was determined with a single-nucleotide polymorphism (SNP) assay, and expression of Schlafen family member 11 (SLFN11) and retinoblastoma transcriptional corepressor 1 (RB1) was evaluated by real-time polymerase chain reaction (RT-PCR) and immunohistochemistry analyses. In addition, the combination of irinotecan and the ataxia telangiectasia and Rad3-related protein (ATR) inhibitor VE-822 was tested in SLFN11-negative PDXs, and two clinical non-camptothecin TOP1 inhibitors (LMP400 and LMP776) were tested. Thirty-eight percent of the TNBC models responded to irinotecan. BRCAness combined with high SLFN11 expression and RB1 loss identified highly sensitive tumors, consistent with the notion that deficiencies in cell cycle checkpoints and DNA repair result in high sensitivity to TOP1 inhibitors. Treatment by the ATR inhibitor VE-822 increased sensitivity to irinotecan in SLFN11-negative PDXs and abolished irinotecan-induced phosphorylation of checkpoint kinase 1 (CHK1). LMP400 (indotecan) and LMP776 (indimitecan) showed high antitumor activity in BRCA1-mutated or BRCAness-positive PDXs. Last, low SLFN11 expression was associated with poor survival in 250 patients with TNBC treated with anthracycline-based chemotherapy. In conclusion, a substantial proportion of TNBC respond to irinotecan. BRCAness, high SLFN11 expression, and RB1 loss are highly predictive of response to irinotecan and the clinical indenoisoquinoline TOP1 inhibitors.

Ewing sarcoma: investigational mono- and combination therapies in clinical trials

INTRODUCTION

Over the last decades, multi-institutional clinical trials have resulted in significant improvements in the outcomes of patients with localized Ewing sarcoma; however, those with metastatic and recurrent diseases continue to fare poorly. More recently, advancements made in understanding the biology of the disease and mechanisms of response to therapy have opened the door for the incorporation of targeted therapies. Here we review the current state of treatment for Ewing sarcoma and the most recent preclinical advancements that have the potential to translate to improved care.

AREAS COVERED

This review provides a general overview of the most recent clinical trials completed in Ewing sarcoma, as well as the preclinical and translational data that has the potential to be incorporated into clinical trials. A PubMed review as well as a review of published meeting abstracts was used to compose this review.

EXPERT OPINION

While dose-intenstifying strategies have failed to lead to improvements in outcomes for patients with the highest-risk disease, recent preclinical advancements have shed light on potential new targeted strategies. The lack of early-phase clinical trial responses should not deter us from further developing these agents, but instead should guide us in designing novel combination strategies.

Longitudinal PET Imaging to Monitor Treatment Efficacy by Liposomal Irinotecan in Orthotopic Patient-Derived Pancreatic Tumor Models of High and Low Hypoxia

Purpose

Hypoxia is linked to aggressiveness, resistance to therapy, and poor prognosis of pancreatic tumors. Liposomal irinotecan (nal-IRI, ONIVYDE®) has shown potential in reducing hypoxia in the HT29 colorectal cancer model, and here, we investigate its therapeutic activity and ability to modulate hypoxia in patient-derived orthotopic tumor models of pancreatic cancer.

Procedures

Mice were randomized into nal-IRI treated and untreated controls. Magnetic resonance imaging was used for monitoring treatment efficacy, positron emission tomography (PET) imaging with F-18-labelled fluoroazomycinarabinoside ([¹⁸F]FAZA) for tumor hypoxia quantification, and F-18-labelled fluorothymidine ([¹⁸F]FLT) for tumor cell proliferation.

Results

The highly hypoxic OCIP51 tumors showed significant response following nal-IRI treatment compared with the less hypoxic OCIP19 tumors. [¹⁸F]FAZA-PET detected significant hypoxia reduction in treated OCIP51 tumors, 8 days before significant changes in tumor volume. OCIP19 tumors also responded to therapy, although tumor volume control was not accompanied by any reduction in [¹⁸F]FAZA uptake. In both models, no differences were observable in [¹⁸F]FLT uptake in treated tumors compared with control mice.

Conclusions

Hypoxia modulation may play a role in nal-IRI’s mechanism of action. Nal-IRI demonstrated greater anti-tumor activity in the more aggressive and hypoxic tumor model. Furthermore, hypoxia imaging provided early prediction of treatment response.

Electronic supplementary material

The online version of this article (10.1007/s11307-019-01374-x) contains supplementary material, which is available to authorized users.

Chromatin Remodeling and Immediate Early Gene Activation by SLFN11 in Response to Replication Stress

Schlafen 11 (SLFN11) was recently discovered as a cellular restriction factor against replication stress. Here, we show that SLFN11 increases chromatin accessibility genome wide, prominently at active promoters in response to replication stress induced by the checkpoint kinase 1 (CHK1) inhibitor prexasertib or the topoisomerase I (TOP1) inhibitor camptothecin. Concomitantly, SLFN11 selectively activates cellular stress response pathways by inducing the transcription of the immediate early genes (IEGs), including JUN, FOS, EGR1, NFKB2, and ATF3, together with the cell cycle arrest genes CDKN1A (p21^WAF1) and GADD45. Both chromatin remodeling and IEG activation require the putative ATPase and helicase activity of SLFN11, whereas canonical extrinsic IEG activation is SLFN11 independent. SLFN11-dependent IEG activation by camptothecin is also observed across 55 non-isogenic NCI-60 cell lines. We conclude that SLFN11 acts as a global regulator of chromatin structure and an intrinsic IEG activator with the potential to engage the innate immune activation in response to replicative stress.

Nano-Encapsulation of Mithramycin in Transfersomes and Polymeric Micelles for the Treatment of Sarcomas

Sarcomas are aggressive tumors which often show a poor response to current treatments. As a promising therapeutic alternative, we focused on mithramycin (MTM), a natural antibiotic with a promising anti-tumor activity but also a relevant systemic toxicity. Therefore, the encapsulation of MTM in nano-delivery systems may represent a way to increase its therapeutic window. Here, we designed novel transfersomes and PLGA polymeric micelles by combining different membrane components (phosphatidylcholine, Span 60, Tween 20 and cholesterol) to optimize the nanoparticle size, polydispersity index (PDI) and encapsulation efficiency (EE). Using both thin film hydration and the ethanol injection methods we obtained MTM-loaded transferosomes displaying an optimal hydrodynamic diameter of 100–130 nm and EE values higher than 50%. Additionally, we used the emulsion/solvent evaporation method to synthesize polymeric micelles with a mean size of 228 nm and a narrow PDI, capable of encapsulating MTM with EE values up to 87%. These MTM nano-delivery systems mimicked the potent anti-tumor activity of free MTM, both in adherent and cancer stem cell-enriched tumorsphere cultures of myxoid liposarcoma and chondrosarcoma models. Similarly to free MTM, nanocarrier-delivered MTM efficiently inhibits the signaling mediated by the pro-oncogenic factor SP1. In summary, we provide new formulations for the efficient encapsulation of MTM which may constitute a safer delivering alternative to be explored in future clinical uses.

Vorinostat and fenretinide synergize in preclinical models of T-cell lymphoid malignancies

T-cell lymphoid malignancies (TCLMs) are in need of novel and more effective therapies. The histone deacetylase (HDAC) inhibitors and the synthetic cytotoxic retinoid fenretinide have achieved durable clinical responses in T-cell lymphomas as single agents, and patients who failed prior HDAC inhibitor treatment have responded to fenretinide. We have previously shown fenretinide synergized with the class I HDAC inhibitor romidepsin in preclinical models of TCLMs. There exist some key differences between HDAC inhibitors. Therefore, we determined if the pan-HDAC inhibitor vorinostat synergizes with fenretinide. We demonstrated cytotoxic synergy between vorinostat and fenretinide in nine TCLM cell lines at clinically achievable concentrations that lacked cytotoxicity for non-malignant cells (fibroblasts and blood mononuclear cells). In vivo, vorinostat + fenretinide + ketoconazole (enhances fenretinide exposures by inhibiting fenretinide metabolism) showed greater activity in subcutaneous TCLM xenograft models than other groups. Fenretinide + vorinostat increased reactive oxygen species (ROS, measured by 2',7'-dichlorodihydrofluorescein diacetate dye), resulting in increased apoptosis (via transferase dUTP nick end labeling assay) and histone acetylation (by immunoblotting). The synergistic cytotoxicity, apoptosis, and histone acetylation of fenretinide + vorinostat was abrogated by the antioxidant vitamin C. Like romidepsin, vorinostat combined with fenretinide achieved synergistic cytotoxic activity and increased histone acetylation in preclinical models of TCLMs, but not in non-malignant cells. As vorinostat is an oral agent and not a P-glycoprotein substrate it may have advantages in such combination therapy. These data support conducting a clinical trial of vorinostat combined with fenretinide in relapsed and refractory TCLMs.

Drugs in development for small cell lung cancer

Small cell lung cancer (SCLC) is a particularly lethal subtype of lung cancer whose treatment landscape has been relatively devoid of advance. The recent integration of immunotherapy in the first-line treatment of SCLC has improved overall survival (OS), prompting the first major paradigm shift for this disease in decades. Despite this improvement in outcomes, most patients with SCLC will relapse after initial response. Standard salvage systemic therapy for SCLC remains disappointing, with few approved agents and consistently poor outcomes. The need for novel agents to combat this disease remains pressing. Fortunately, there are several agents in various stages of development that hold potential as novel treatments for advanced SCLC. Lurbinectedin, which targets active transcription, has shown activity in platinum-sensitive and platinum-resistant SCLC as monotherapy and in combination with doxorubicin. Aurora A kinase (AAK) inhibitors showed initial activity when given with paclitaxel but in randomized studies, failed to improve outcomes over paclitaxel plus placebo. However, in the subset of patients with MYC expression, targeting AAK was effective. Similarly, agents targeting poly-ADP ribose (PARP) pair well with other DNA damaging drugs but in the subset of patients whose tumors express Schlafen-11 (SLFN-11), efficacy appeared greater. CDK 4/6 inhibition is being explored, primarily as a means to protect myeloid cells during cytotoxic chemotherapy in a strategy expected to be uniquely effective in SCLC. Ongoing trials are also studying are novel formulations of established cytotoxic agents. Delta-like protein 3 (DLL3) is an appealing therapeutic target given its selective expression on SCLC cells, but after initial exciting results, the antibody-drug conjugate (ADC) Rovalpituzumab tesirine (Rova-T) did not have a favorable efficacy to toxicity profile in randomized trials. Other agents targeting DLL3 are under study. Targeting angiogenesis has yielded modest improvements in the past but newer agents such as anlotinib are renewing interest. While the current therapeutic landscape beyond chemo-immunotherapy remains the same as it was decades ago, drug development for SCLC is rapidly moving forward and promises to deliver the needed novel agents in the very near future.

A phase II study of liposomal irinotecan with 5-fluorouracil, leucovorin and oxaliplatin in patients with resectable pancreatic cancer: the nITRO trial

Background:

Up-front surgery followed by postoperative chemotherapy remains the standard paradigm for the treatment of patients with resectable pancreatic cancer. However, the risk for positive surgical margins, the poor recovery after surgery that often impairs postoperative treatment, and the common metastatic relapse limit the overall clinical outcomes achieved with this strategy. Polychemotherapeutic combinations are valid options for postoperative treatment in patients with good performance status. liposomal irinotecan (Nal-IRI) is a novel nanoliposome formulation of irinotecan that accumulates in tumor-associated macrophages improving the therapeutic index of irinotecan and has been approved for the treatment of patients with metastatic pancreatic cancer after progression under gemcitabine-based therapy. Thus, it remains of the outmost urgency to investigate introduction of the most novel agents, such as nal-IRI, in perioperative approaches aimed at increasing the long-term effectiveness of surgery.

Methods:

The nITRO trial is a phase II, single-arm, open-label study to assess the safety and the activity of nal-IRI with fluorouracil/leucovorin (5-FU/LV) and oxaliplatin in the perioperative treatment of patients with resectable pancreatic cancer. The primary tumor must be resectable with no involvement of the major arteries and no involvement or <180° interface between tumor and vessel wall of the major veins. A total of 72 patients will be enrolled to receive a perioperative treatment of three cycles before and three cycles after surgical resection with nal-IRI 50 mg/m², oxaliplatin 60 mg/m², leucovorin 200 mg/m², and 5-fluorouracil 2400 mg/m2, days 1 and 15 of a 28-day cycle. The primary objective is to improve from 40% to 55% the proportion of patients achieving R0 resection after preoperative treatment.

Discussion:

The nITRO trial will contribute to strengthen the clinical evidence supporting perioperative strategies in resectable pancreatic cancer patients. Moreover, this study represents a unique opportunity for translational analyses aimed to identify novel immune-related prognostic and predictive factors in this setting.

Trial registration

Clinicaltrial.gov: NCT03528785. Trial registration data: 1 January 2018

Protocol number: CRC 2017_01

EudraCT Number: 2017-000345-46

Structural Optimization and Enhanced Prodrug-Mediated Delivery Overcomes Camptothecin Resistance in High-Risk Solid Tumors

Camptothecins are potent topoisomerase I inhibitors used to treat high-risk pediatric solid tumors, but they often show poor efficacy due to intrinsic or acquired chemoresistance. Here, we developed a multivalent, polymer-based prodrug of a structurally optimized camptothecin (SN22) designed to overcome key chemoresistance mechanisms. The ability of SN22 vs. SN38 (the active form of irinotecan/CPT-11) to overcome efflux pump-driven drug resistance was tested. Tumor uptake and biodistribution of SN22 as a polymer-based prodrug (PEG-[SN22]₄) compared with SN38 was determined. The therapeutic efficacy of PEG-[SN22]₄ to CPT-11 was compared in: (i) spontaneous neuroblastomas (NB) in transgenic TH-MYCN mice; (ii) orthotopic xenografts of a drug-resistant NB line SK-N-BE(2)C (mutated TP53); (iii) flank xenografts of a drug-resistant NB-PDX; and (iv) xenografts of Ewing sarcoma and rhabdomyosarcoma. Unlike SN38, SN22 inhibited NB cell growth regardless of ABCG2 expression levels. SN22 prodrug delivery resulted in sustained intratumoral drug concentrations, dramatically higher than those of SN38 at all time points. CPT-11/SN38 treatment had only marginal effects on tumors in transgenic mice, but PEG-[SN22]₄ treatment caused complete tumor regression lasting over 6 months (tumor free at necropsy). PEG-[SN22]₄ also markedly extended survival of mice with drug-resistant, orthotopic NB and it caused long-term (6+ months) remissions in 80% to 100% of NB and sarcoma xenografts. SN22 administered as a multivalent polymeric prodrug resulted in increased and protracted tumor drug exposure compared with CPT-11, leading to long-term "cures" in NB models of intrinsic or acquired drug resistance, and models of high-risk sarcomas, warranting its further development for clinical trials. SIGNIFICANCE: SN22 is an effective and curative multivalent macromolecular agent in multiple solid tumor mouse models, overcoming common mechanisms of drug resistance with the potential to elicit fewer toxicities than most cancer therapeutics.

A phase I trial of talazoparib and irinotecan with and without temozolomide in children and young adults with recurrent or refractory solid malignancies

BACKGROUND

Talazoparib combined with irinotecan and temozolomide demonstrated efficacy in a murine Ewing sarcoma model. Based on these data, we conducted a phase I trial of talazoparib and irinotecan with/without temozolomide in paediatric patients with recurrent/refractory solid malignancies.

PATIENTS AND METHODS

Cohorts of 3-6 patients with recurrent/refractory solid malignancies received escalating doses of oral talazoparib and intravenous irinotecan (arm A) and oral talazoparib, oral temozolomide and intravenous irinotecan (arm B) in a 3 + 3 design. Talazoparib was administered on days 1-6, and intravenous irinotecan and oral temozolomide were administered on days 2-6, of a 21-day course. Serum for talazoparib and irinotecan pharmacokinetics was obtained during course 1. UGT1A1 polymorphism and Schlafen family member 11 (SLFN11) immunohistochemical staining were performed.

RESULTS

Forty-one patients (20 males; median age, 14.6 years; 24 with recurrent disease) were evaluable for dose escalation. Twenty-nine and 12 patients were treated on arm A and arm B, respectively, for a total of 208 courses. The most common diagnosis was Ewing sarcoma (53%). The most common ≥grade III haematologic toxicities in arms A and B included neutropenia (78% and 31%, respectively) and thrombocytopenia (42% and 31%, respectively). In arms A and B, febrile neutropenia (24% and 14%, respectively) and diarrhoea (21% and 7%, respectively) were the most common ≥grade III non-hematologic toxicities. Six patients (Ewing sarcoma [5 patients] and synovial sarcoma [1 patient]) had a response (1 with a complete response, 5 with a partial response). The objective response rates were 10.3% (arm A) and 25% (arm B). Pharmacokinetic testing demonstrated no evidence of drug-drug interaction between talazoparib and irinotecan. UGT1A1 was not related to response. SLFN11 positivity was associated with best response to therapy.

CONCLUSIONS

The combination of talazoparib and irinotecan with/without temozolomide is feasible and active in Ewing sarcoma, and further investigation is warranted.

Nanoparticle-Based Drug Delivery System: A Patient-Friendly Chemotherapy for Oncology

Chemotherapy is widely used to treat cancer. The toxic effect of conventional chemotherapeutic drugs on healthy cells leads to serious toxic and side effects of conventional chemotherapy. The application of nanotechnology in tumor chemotherapy can increase the specificity of anticancer agents, increase the killing effect of tumors, and reduce toxic and side effects. Currently, a variety of formulations based on nanoparticles (NPs) for delivering chemotherapeutic drugs have been put into clinical use, and several others are in the stage of development or clinical trials. In this review, after briefly introducing current cancer chemotherapeutic methods and their limitations, we describe the clinical applications and advantages and disadvantages of several different types of NPs-based chemotherapeutic agents. We have summarized a lot of information in tables and figures related to the delivery of chemotherapeutic drugs based on NPs and the design of NPs with active targeting capabilities.

Immunohistochemical analysis of SLFN11 expression uncovers potential non-responders to DNA-damaging agents overlooked by tissue RNA-seq

DNA-damaging agents include first-line drugs such as platinum (cisplatin, carboplatin), topoisomerase inhibitors (etoposide, doxorubicin), and replication inhibitors (cytarabine, gemcitabine). Despite their wide and long usage, there is no clinically available biomarker to predict responses to these drugs. Schlafen 11 (SLFN11), a putative DNA/RNA helicase, recently emerged as a dominant determinant of sensitivity to these drugs by enforcing the replication block in response to DNA damage. Since the clinical importance of SLFN11 is implicated, a comprehensive analysis of SLFN11 expression across human organs will provide a practical resource to develop the utility of SLFN11 in the clinic. In this study, we established a scoring system of SLFN11 expression by immunohistochemistry (IHC) and assessed SLFN11 expression in ~ 700 malignant as well as the adjacent non-tumor tissues across 16 major human adult organs. We found that the SLFN11 expression is tissue specific and varies during tumorigenesis. Although The Cancer Genome Atlas (TCGA) is a prevailing tool to assess gene expression in various malignant and normal tissues, our IHC data exhibited obvious discrepancy from the TCGA data in several organs. Importantly, SLFN11-negative tumors, potentially non-responders to DNA-damaging agents, were largely overrated in TCGA because TCGA samples are a mixture of infiltrating immune cells, including T cells, B cells, and macrophages, which have strong SLFN11 expression. Thus, our study reveals the significance of immunohistochemical procedures for evaluating expression of SLFN11 in patient samples and provides a robust resource of SLFN11 expression across adult human organs.

Sarcoma as Second Cancer in a Childhood Cancer Survivor: Case Report, Large Population Analysis and Literature Review

The majority of pediatric patients are cured of their primary cancer with current advanced developments in pediatric cancer therapy. However, survivors often experience long-term complications from therapies for primary cancer. The delayed mortality rate has been decreasing with the effort to reduce the therapeutic exposure of patients with pediatric cancers. Our study investigates the incidence of sarcoma as second cancer in pediatric cancer survivors. We present a 9-year-old male who survived embryonal hepatoblastoma diagnosed at 22 months of age. At 4.5 years of age, he presented with a non-metastatic primitive neuroectodermal tumor (PNET) of the left submandibular area. He has no evidence of recurrence of either cancer for 51 months after finishing all chemotherapy and radiotherapy. We used the Surveillance, Epidemiology, and End Results (SEER) database to identify the current rate of second sarcomas in pediatric cancer survivors. Our literature review and large population analysis emphasize the impact of sarcoma as a second malignancy and provide help to physicians caring for pediatric cancer survivors.

Axial pharmaceutical properties of liposome in cancer therapy: Recent advances and perspectives

Evaluation of axial properties including preparation, surface functionalization, and pharmacokinetics for delivery of pharmacologically active molecules and genes lead to pharmaceutical development of liposome in cancer therapy. Here, analysis of effects of the axial properties of liposome based on cancer treatment modalities as individually and coherently is vital and shows deserving further investigation for the future. In this review, recent progress in the analysis of preparation approaches, optimizing pharmacokinetic parameters, functionalization and targeting improvement and modulation of biological factors and components resulting in a better function of liposome in cancer for drug/gene delivery and immunotherapy are discussed. Here, recent developments on liposome with vaccines and immunoadjuvant carriers, and antigen-carrier system to cancer immunotherapy are introduced.

Anti-Metastatic Effects on Melanoma via Intravenous Administration of Anti-NF-κB siRNA Complexed with Functional Peptide-Modified Nano-Micelles

Controlling metastasis is an important strategy in cancer treatment. Nanotechnology and nucleic acids with novel modalities are promising regulators of cancer metastasis. We aimed to develop a small interfering RNA (siRNA) systemic delivery and anti-metastasis system using nanotechnology. We previously reported that polyethylene glycol-polycaprolactone (PEG-PCL) and functional peptide CH2R4H2C nano-micelle (MPEG-PCL-CH2R4H2C) has high siRNA silencing effects, indicated by increased drug accumulation in tumor-bearing mice, and has an anti-tumor effect on solid tumors upon systemic injection. In this study, we aimed to apply our micelles to inhibit metastasis and evaluated the inhibitory effect of anti-RelA siRNA (siRelA), which is a subunit of NF-κB conjugated with MPEG-PCL-CH2R4H2C, via systemic administration. We report that siRelA/MPEG-PCL-CH2R4H2C had a high cellular uptake and suppressed the migration/invasion of cells in B16F10 cells without toxicity. In addition, in a lung metastasis mouse model using intravenous administration of B16F10 cells treated with siRelA/MPEG-PCL-CH2R4H2C, the number of lung nodules in lung tissue significantly decreased compared to naked siRelA and siControl/MPEG-PCL-CH2R4H2C micelle treatments. Hence, we show that RelA expression can reduce cancer metastasis, and MPEG-PCL-CH2R4H2C is an effective siRNA carrier for anti-metastasis cancer therapies.

Topoisomerase inhibitors: Pharmacology and emerging nanoscale delivery systems

Topoisomerase enzymes have shown unique roles in replication and transcription. These enzymes which were initially found in Escherichia coli have attracted considerable attention as target molecules for cancer therapy. Nowadays, there are several topoisomerase inhibitors in the market to treat or at least control the progression of cancer. However, significant toxicity, low solubility and poor pharmacokinetic properties have limited their wide application and these characteristics need to be improved. Nano-delivery systems have provided an opportunity to modify the intrinsic properties of molecules and also to transfer the toxic agent to the target tissues. These delivery systems leads to the re-introduction of existing molecules present in the market as novel therapeutic agents with different physicochemical and pharmacokinetic properties. This review focusses on a variety of nano-delivery vehicles used for the improvement of pharmacological properties of topoisomerase inhibitors and thus enabling their potential application as novel drugs in the market.

Nal-IRI with 5-fluorouracil (5-FU) and leucovorin or gemcitabine plus cisplatin in advanced biliary tract cancer - the NIFE trial (AIO-YMO HEP-0315) an open label, non-comparative, randomized, multicenter phase II study

Background

Biliary tract cancer (BTC) has a high mortality. Primary diagnosis is frequently delayed due to mostly unspecific symptoms, resulting in a high number of advanced cases at the time of diagnosis. Advanced BTCs are in principle chemotherapy sensitive as determined by improved disease control, survival and quality of life (QoL). However, median OS does not exceed 11.7 months with the current standard of care gemcitabine plus cisplatin. Thereby, novel drug formulations like nanoliposomal-irinotecan (nal-IRI) in combination with 5- fluorouracil (5-FU)/leucovorin may have the potential to improve therapeutic outcomes in this disease.

Methods

NIFE is an interventional, prospective, randomized, controlled, open label, two-sided phase II study. Within the study, 2 × 46 patients with locally advanced, non-resectable or metastatic BTC are to be enrolled by two stage design of Simon. Data analysis will be done unconnected for both arms. Patients are allocated in two arms: Arm A (experimental intervention) nal-IRI mg/m², 46 h infusion)/5-FU (2400 mg/m², 46 h infusion)/leucovorin (400 mg/m², 0.5 h infusion) d1 on 14 day-cycles; Arm B (standard of care) cisplatin (25 mg/m², 1 h infusion)/gemcitabine (1000 mg/m², 0.5 h infusion) d1 and d8 on 21 day-cycles. The randomization (1:1) is stratified for tumor site (intrahepatic vs. extrahepatic biliary tract), disease stage (advanced vs. metastatic), age (≤70 vs. > 70 years), sex (male vs. female) and WHO performance score (ECOG 0 vs. ECOG 1). Primary endpoint of the study is the progression free survival (PFS) rate at 4 months after randomization by an intention-to-treat analysis in each of the groups. Secondary endpoints are the overall PFS rate, the 3-year overall survival rate, the disease control rate after 2 months, safety and patient related outcome with quality of life. The initial assessment of tumor resectability for locally advanced BTCs is planned to be reviewed retrospectively by a central surgical board. Exploratory objectives aim at establishing novel biomarkers and molecular signatures to predict response. The study was initiated January 2018 in Germany.

Discussion

The NIFE trial evaluates the potential of a nanoliposomal-irinotecan/5-FU/leucovorin combination in the first line therapy of advanced BTCs and additionally offers a unique chance for translational research.

Trial registration

Clinicaltrials.gov NCT03044587. Registration Date February 7th 2017.

An update on treatment options for pancreatic adenocarcinoma

Pancreatic cancer is one of the most lethal solid organ tumors. Due to the rising incidence, late diagnosis, and limited treatment options, it is expected to be the second leading cause of cancer deaths in high income countries in the next decade. The multidisciplinary treatment of this disease depends on the stage of cancer at diagnosis (resectable, borderline, locally advanced, and metastatic disease), and combines surgery, chemotherapy, chemoradiotherapy, and supportive care. The landscape of multidisciplinary pancreatic cancer treatment is changing rapidly, especially in locally advanced disease, and the number of treatment options in metastatic disease, including personalized medicine, innovative targets, immunotherapy, therapeutic vaccines, adoptive T-cell transfer, or stemness inhibitors, will probably expand in the near future. This review summarizes the current literature and provides an overview of how new therapies or new therapeutic strategies (neoadjuvant therapies, conversion surgery) will guide multidisciplinary disease management, future clinical trials, and, hopefully, will increase overall survival.

Soy Lecithin-Derived Liposomal Delivery Systems: Surface Modification and Current Applications

The development of natural phospholipids for nanostructured drug delivery systems has attracted much attention in the past decades. Lecithin that was derived from naturally occurring in soybeans (SL) has introduced some auspicious accomplishments to the drug carrying aspect, like effectual encapsulation, controlled release, and successful delivery of the curative factors to intracellular regions in which they procure these properties from their flexible physicochemical and biophysical properties, such as large aqueous center and biocompatible lipid, self-assembly, tunable properties, and high loading capacity. Despite the almost perfect properties as a drug carrier, liposome is known to be quite quickly eliminated from the body systems. The surface modification of liposomes has been investigated in many studies to overcome this drawback. In this review, we intensively discussed the surface-modified liposomes that enhancing the targeting, cellular uptake, and therapeutic response. Moreover, the recent applications of soy lecithin-derived liposome, focusing on cancer treatment, brain targeting, and vaccinology, are also summarized.

Schlafen 11 (SLFN11), a restriction factor for replicative stress induced by DNA-targeting anti-cancer therapies

Schlafen 11 (SLFN11) sensitizes cells to a broad range of anti-cancer drugs including platinum derivatives (cisplatin and carboplatin), inhibitors of topoisomerases (irinotecan, topotecan, doxorubicin, daunorubicin, mitoxantrone and etoposide), DNA synthesis inhibitors (gemcitabine, cytarabine, hydroxyurea and nucleoside analogues), and poly(ADPribose) polymerase (PARP) inhibitors (olaparib, rucaparib, niraparib and talazoparib). In spite of their different primary mechanisms of action, all these drugs damage DNA during S-phase, activate the intra-S-phase checkpoint and induce replication fork slowing and stalling with single-stranded DNA segments coated with replication protein A. Such situation with abnormal replication forks is known as replication stress. SLFN11 irreversibly blocks replication in cells under replication stress, explaining why SLFN11-positive cells are markedly more efficiently killed by DNA-targeting drugs than SLFN11-negative cells. SLFN11 is inactivated in ~50% of cancer cell lines and in a large fraction of tumors, and is linked with the native immune, interferon and T-cells responses, implying the translational relevance of measuring SLFN11 expression as a predictive biomarker of response and resistance in patients. SLFN11 is also a plausible epigenetic target for reactivation by inhibitors of histone deacetylases (HDAC), DNA methyltransferases (DNMT) and EZH2 histone methyltransferase and for combination of these epigenetic inhibitors with DNA-targeting drugs in cells lacking SLFN11 expression. In addition, resistance due to lack of SLFN11 expression in tumors is a potential indication for cell-cycle checkpoint inhibitors in combination with DNA-targeting therapies.

Wnt/β-Catenin Signaling: The Culprit in Pancreatic Carcinogenesis and Therapeutic Resistance

Pancreatic ductal adenocarcinoma (PDAC) is responsible for 7.3% of all cancer deaths. Even though there is a steady increase in patient survival for most cancers over the decades, the patient survival rate for pancreatic cancer remains low with current therapeutic strategies. The Wnt/β-catenin pathway controls the maintenance of somatic stem cells in many tissues and organs and is implicated in pancreatic carcinogenesis by regulating cell cycle progression, apoptosis, epithelial-mesenchymal transition (EMT), angiogenesis, stemness, tumor immune microenvironment, etc. Further, dysregulated Wnt has been shown to cause drug resistance in pancreatic cancer. Although different Wnt antagonists are effective in pancreatic patients, limitations remain that must be overcome to increase the survival benefits associated with this emerging therapy. In this review, we have summarized the role of Wnt signaling in pancreatic cancer and suggested future directions to enhance the survival of pancreatic cancer patients.

SLFN11 is a general target for enhancing the sensitivity of cancer to chemotherapy (DNA-damaging agents)

In patients with cancer, drug tolerance often occurs during the use of chemotherapy drugs, seriously affecting patient prognosis and survival. Therefore, scientists began to study the factors that affect chemotherapy drug sensitivity, and the high correlation between Schlafen-11 (SLFN11) and sensitivity to chemical drugs (mainly DNA-damaging agents, DDAs) has received increasing attention since it was discovered through bioinformatics analyses. Regarding the mechanism, SLFN11 may sensitise cells to chemotherapy drugs by preventing DNA damage repair. In recent years, SLFN11 has gradually become a hot research topic, and the results are enriching our understanding of this molecule. Indeed, the biological functions of SLFN11 under normal physiological conditions and in cancer, changes in its expression levels and mechanisms promoting apoptosis within the context of chemotherapeutic interventions have gradually been uncovered. Studies to date provide knowledge and the experimental and theoretical bases underlying SLFN11 and its effects on sensitivity to chemotherapy drugs. This review summarises the existing research on SLFN11 with the aim of achieving a more comprehensive understanding and furthering the development of strategies to target SLFN11 in the treatment of cancer.

Diagnostic Clinical Trials in Breast Cancer Brain Metastases: Barriers and Innovations

Optimal treatment of breast cancer brain metastases (BCBM) is often hampered by limitations in diagnostic abilities. Developing innovative tools for BCBM diagnosis is vital for early detection and effective treatment. In this study we explored the advances in trial for the diagnosis of BCBM, with review of the literature. On May 8, 2019, we searched ClinicalTrials.gov for interventional and diagnostic clinical trials involving BCBM, without limiting for date or location. Information on trial characteristics, experimental interventions, results, and publications were collected and analyzed. In addition, a systematic review of the literature was conducted to explore published studies related to BCBM diagnosis. Only 9 diagnostic trials explored BCBM. Of these, 1 trial was withdrawn because of low accrual numbers. Three trials were completed; however, none had published results. Modalities in trial for BCBM diagnosis entailed magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), PET-CT, nanobodies, and circulating tumor cells (CTCs), along with a collection of novel tracers and imaging biomarkers. MRI continues to be the diagnostic modality of choice, whereas CT is best suited for acute settings. Advances in PET and PET-CT allow the collection of metabolic and functional information related to BCBM. CTC characterization can help reflect on the molecular foundations of BCBM, whereas cell-free DNA offers new genetic material for further exploration in trials. The integration of machine learning in BCBM diagnosis seems inevitable as we continue to aim for rapid and accurate detection and better patient outcomes.

Complement therapeutics meets nanomedicine: overcoming human complement activation and leukocyte uptake of nanomedicines with soluble domains of CD55

Complement activation plays an important role in pharmacokinetic and performance of intravenously administered nanomedicines. Significant efforts have been directed toward engineering of nanosurfaces with low complement activation, but due to promiscuity of complement factors and redundancy of pathways, it is still a major challenge. Cell membrane-anchored Decay Accelerating Factor (DAF, a.k.a. CD55) is an efficient membrane bound complement regulator that inhibits both classical and alternative C3 convertases by accelerating their spontaneous decay. Here we tested the effect of various short consensus repeats (SCRs, "sushi" domains) of human CD55 on nanoparticle-mediated complement activation in human sera and plasma. Structural modeling suggested that SCR-2, SCR-3 and SCR-4 are critical for binding to the alternative pathway C3bBb convertase, whereas SCR-1 is dispensable. Various domains were expressed in E.coli and purified by an affinity column. SCRs were added to lepirudin plasma or sera from different healthy subjects, to monitor nanoparticle-mediated complement activation as well as C3 opsonization. Using superparamagnetic iron oxide nanoworms (SPIO NWs), we found that SCR-2-3-4 was the most effective inhibitor (IC50 ~0.24 μM for C3 opsonization in sera), followed by SCR-1-2-3-4 (IC50 ~0.6 μM), whereas shorter domains (SCR-3, SCR-2-3, SCR-3-4) were ineffective. SCR-2-3-4 also inhibited C5a generation (IC50 ~0.16 μM in sera). In addition to SPIO NWs, SCR-2-3-4 effectively inhibited C3 opsonisation and C5a production by clinically approved nanoparticles (Feraheme, LipoDox and Onivyde). SCR-2-3-4 inhibited both lectin and alternative pathway activation by nanoparticles. When added to lepirudin-anticoagulated blood from healthy donors, it significantly reduced the uptake of SPIO NWs by neutrophils and monocytes. These results suggest that soluble domains of membrane-bound complement inhibitors are potential candidates for preventing nanomedicine-mediated complement activation in human subjects.

Management of recurrent Ewing sarcoma: challenges and approaches

Although many patients with newly diagnosed Ewing sarcoma can become long-term survivors, relapse remains an important clinical problem for which there is no standard approach. Several prognostic factors have been identified, and these may help guide patient counseling and therapy decisions. A variety of chemotherapy regimens have produced responses in patients with recurrent Ewing sarcoma, but no comparative studies have been completed to show superiority of any one particular approach. In addition, the optimum length of therapy for salvage regimens and use of local control measures remains unknown. The likelihood of cure remains low and the gaps in our knowledge are great, and so enrollment on clinical trials should be strongly encouraged for these patients when feasible. Because Ewing sarcoma is relatively rare, some pediatric and adult oncologists may be less familiar with the management of relapsed patients. In this review, we address common questions facing the clinician and patient, and provide an update on new strategies for therapy.

Immunoglobulin deposition on biomolecule corona determines complement opsonization efficiency of preclinical and clinical nanoparticles

Deposition of complement factors (opsonization) on nanoparticles may promote clearance from the blood by macrophages and trigger proinflammatory responses, but the mechanisms regulating the efficiency of complement activation are poorly understood. We previously demonstrated that opsonization of superparamagnetic iron oxide (SPIO) nanoworms with the third complement protein (C3) was dependent on the biomolecule corona of the nanoparticles. Here we show that natural antibodies play a critical role in C3 opsonization of SPIO nanoworms and a range of clinically approved nanopharmaceuticals. The dependency of C3 opsonization on immunoglobulin binding is almost universal and is observed regardless of the complement activation pathway. Only a few surface-bound immunoglobulin molecules are needed to trigger complement activation and opsonization. Although the total amount of plasma proteins adsorbed on nanoparticles does not determine C3 deposition efficiency, the biomolecule corona per se enhances immunoglobulin binding to all nanoparticle types. We therefore show that natural antibodies represent a link between biomolecule corona and C3 opsonization, and may determine individual complement responses to nanomedicines.