Lessons Learned from Two Decades of Anticancer Drugs

Study of serious adverse drug reactions using FDA-approved drug labeling and MedDRA

BACKGROUND

Adverse Drug Reactions (ADRs) are of great public health concern. FDA-approved drug labeling summarizes ADRs of a drug product mainly in three sections, i.e., Boxed Warning (BW), Warnings and Precautions (WP), and Adverse Reactions (AR), where the severity of ADRs are intended to decrease in the order of BW > WP > AR. Several reported studies have extracted ADRs from labeling documents, but most, if not all, did not discriminate the severity of the ADRs by the different labeling sections. Such a practice could overstate or underestimate the impact of certain ADRs to the public health. In this study, we applied the Medical Dictionary for Regulatory Activities (MedDRA) to drug labeling and systematically analyzed and compared the ADRs from the three labeling sections with a specific emphasis on analyzing serious ADRs presented in BW, which is of most drug safety concern.

RESULTS

This study investigated New Drug Application (NDA) labeling documents for 1164 single-ingredient drugs using Oracle Text search to extract MedDRA terms. We found that only a small portion of MedDRA Preferred Terms (PTs), 3819 out of 21,920 or 17.42%, were observed in a whole set of documents. In detail, 466/3819 (12.0%) PTs were in BW, 2023/3819 (53.0%) were in WP, and 2961/3819 (77.5%) were in AR sections. We also found a higher overlap of top 20 occurring BW PTs with WP sections compared to AR sections. Within the MedDRA System Organ Class levels, serious ADRs (sADRs) from BW were prevalent in Nervous System disorders and Vascular disorders. A Hierarchical Cluster Analysis (HCA) revealed that drugs within the same therapeutic category shared the same ADR patterns in BW (e.g., nervous system drug class is highly associated with drug abuse terms such as dependence, substance abuse, and respiratory depression).

CONCLUSIONS

This study demonstrated that combining MedDRA standard terminologies with data mining techniques facilitated computer-aided ADR analysis of drug labeling. We also highlighted the importance of labeling sections that differ in seriousness and application in drug safety. Using sADRs primarily related to BW sections, we illustrated a prototype approach for computer-aided ADR monitoring and studies which can be applied to other public health documents.

Superior proapoptotic activity of curcumin-loaded mixed block copolymer micelles with mitochondrial targeting properties

Targeting tumor cell mitochondria is a prospective strategy for highly effective anticancer therapy. Consequently, the development of potent systems for the targeted delivery of mitochondria-acting therapeutics to mitochondria has the potential to boost this sector of nanomedicine. In this study, a functional mixed micellar system based on two co-assembled triblock copolymers, poly(2-(dimethylamino)ethyl methacrylate)-b-poly(ε-caprolactone)-b-poly(2-(dimethylamino)ethyl methacrylate) bearing triphenylphosphonium ligands (PDMAEMA(TPP+)20-b-PCL70-b-PDMAEMA(TPP+)20) and poly(ethylene oxide)-b-poly(ε-caprolactone)-b-poly(ethylene oxide) (PEO113-b-PCL70-b-PEO113), was assessed for the mitochondria targeted delivery of curcumin. The high proapoptotic activity of the system and the sub-cellular mechanisms of cytotoxicity were demonstrated using a chemosensitive HL-60 cell line and its resistant alternative HL-60/DOX. Next, the successful localization of nanocarriers in mitochondria was proved by fluorescence microscopy with the aid of DAPI (4',6-diamidino-2-phenylindole) as a cellular localization tracker. The in vitro experiments revealed the great potential of the functional system developed for the targeted delivery of curcumin to mitochondria, causing programmed tumor cell death.

Induction of apoptosis by chalepin through phosphatidylserine externalisations and DNA fragmentation in breast cancer cells (MCF7)

AIMS

Chalepin, a naturally occurring compound isolated from Ruta angustifolia have been shown to exert a promising anticancer activity through various mechanisms. Hence, the need to investigate the apoptotic inducing ability of chalepin in MCF7 cells by various detection assays.

MATERIALS AND METHODS

Cytotoxicity screening of chalepin against MCF7 cells was conducted using SRB assay. Apoptosis induction was examined by established morphological and biochemical assays including phase contrast and Hoechst/PI staining fluorescence microscope. Similarly, Annexin-V/FITC and TUNEL assays were conducted using flow cytometry whereas caspase-3 activity was evaluated using microplate reader.

KEY FINDINGS

The result indicates remarkable cytotoxic activity against MCF7 cells, whereas it shows moderate cytotoxic activity against MDA-MB231 cells. Interestingly, chalepin did not present any toxicity against MRC5 normal cell line. Morphological examination using both phase contrast and fluorescence microscope displays typical apoptotic features such as membrane blebbing, DNA fragmentation, chromatin condensation and apoptotic bodies' formation following chalepin treatment against MCF7 cells at different concentration for 48 h. Apoptosis induction is significantly associated with externalisation of phosphatidylserine, and DNA fragmentation in MCF7 cells chalepin treated cells when compared with control. The protein expressions of caspase-8, 9 and cleaved PARP1 were upregulated which correlated well with increased caspase-3 activity.

SIGNIFICANCE

From our recent findings, chalepin was able to induced apoptosis in MCF7 cells and therefore, could be evaluated further as a potential source of anticancer agent for cancer treatment such as breast cancer.

Induction of apoptosis via proteasome inhibition in leukemia/lymphoma cells by two potent piperidones

PURPOSE

Previously, compounds containing a piperidone structure have been shown to be highly cytotoxic to cancer cells. Recently, we found that the piperidone compound P2 exhibits a potent anti-neoplastic activity against human breast cancer-derived cells. Here, we aimed to evaluate two piperidone compounds, P1 and P2, for their potential anti-neoplastic activity against human leukemia/lymphoma-derived cells.

METHODS

Cytotoxicity and apoptosis induction were evaluated using MTS, annexin V-FITC/PI and mitochondrial membrane potential polychromatic assays to confirm the mode of action of the piperidone compounds. The effects of compound P1 and P2 treatment on gene expression were assessed using AmpliSeq analysis and, subsequently, confirmed by RT-qPCR and Western blotting.

RESULTS

We found that the two related piperidone compounds P1 and P2 selectively killed the leukemia/lymphoma cells tested at nanomolar concentrations through induction of the intrinsic apoptotic pathway, as demonstrated by mitochondrial depolarization and caspase-3 activation. AmpliSeq-based transcriptome analyses of the effects of compounds P1 and P2 on HL-60 acute leukemia cells revealed a differential expression of hundreds of genes, 358 of which were found to be affected by both. Additional pathway analyses revealed that a significant number of the common genes were related to the unfolded protein response, implying a possible role of the two compounds in the induction of proteotoxic stress. Subsequent analyses of the transcriptome data revealed that P1 and P2 induced similar gene expression alterations as other well-known proteasome inhibitors. Finally, we found that Noxa, an important mediator of the activity of proteasome inhibitors, was significantly upregulated at both the mRNA and protein levels, indicating a possible role in the cytotoxic mechanism induced by P1 and P2.

CONCLUSIONS

Our data indicate that the cytotoxic activity of P1 and P2 on leukemia/lymphoma cells is mediated by proteasome inhibition, leading to activation of pro-apoptotic pathways.

Tailoring a lead-like compound targeting multiple G-quadruplex structures

A focused library of analogs of a lead-like G-quadruplex (G4) targeting compound (4), sharing a furobenzoxazine naphthoquinone core and differing for the pendant groups on the N-atom of the oxazine ring, has been here analyzed with the aim of developing more potent and selective ligands. These molecules have been tested vs. topologically different G4s by the G4-CPG assay, an affinity chromatography-based method for screening putative G4 ligands. The obtained results showed that all these compounds were able to bind several G4 structures, both telomeric and extra-telomeric, thus behaving as multi-target ligands, and two of them fully discriminated G4 vs. duplex DNA. Biological assays proved that almost all the compounds produced effective DNA damage, showing marked antiproliferative effects on tumor cells in the low μM range. Combined analysis of the G4-CPG binding assays and biological data led us to focus on compound S4-5, proved to be less cytotoxic than the parent compound 4 on normal cells. An in-depth biophysical characterization of the binding of S4-5 to different G4s showed that the here identified ligand has higher affinity for the G4s and higher ability to discriminate G4 vs. duplex DNA than 4. Molecular docking studies, in agreement with the NMR data, suggest that S4-5 interacts with the accessible grooves of the target G4 structures, giving clues for its increased G4 vs. duplex selectivity.

The fruit fly Drosophila melanogaster as an innovative preclinical ADME model for solute carrier membrane transporters, with consequences for pharmacology and drug therapy

Solute carrier membrane transporters (SLCs) control cell exposure to small-molecule drugs, thereby contributing to drug efficacy and failure and/or adverse effects. Moreover, SLCs are genetically linked to various diseases. Hence, in-depth knowledge of SLC function is fundamental for a better understanding of disease pathophysiology and the drug development process. Given that the model organism Drosophila melanogaster (fruit fly) expresses SLCs, such as for the excretion of endogenous and toxic compounds by the hindgut and Malpighian tubules, equivalent to human intestine and kidney, this system appears to be a promising preclinical model to use to study human SLCs. Here, we systematically compare current knowledge of SLCs in Drosophila and humans and describe the Drosophila model as an innovative tool for drug development.

Controlled Pore Glass-based oligonucleotide affinity support: towards High Throughput Screening methods for the identification of conformation-selective G-quadruplex ligands

Target selectivity is one of the main challenges in the search for small molecules able to act as effective and non-toxic anticancer and/or antiviral drugs. To achieve this goal, handy, rapid and reliable High Throughput Screening methodologies are needed. We here describe a novel functionalization for the solid phase synthesis of oligonucleotides on Controlled Pore Glass, including a flexible hexaethylene glycol spacer linking the first nucleoside through the nucleobase via a covalent bond stable to the final deprotection step. This allowed us preparing fully deprotected oligonucleotides still covalently attached to their supports. In detail, on this support we performed both the on-line synthesis of different secondary structure-forming oligonucleotides and the affinity chromatography-based screenings of conformation-selective G-quadruplex ligands. By using a fluorescent core-extended naphthalene diimide with different emitting response upon binding to sequences folding into G-quadruplexes of different topologies, we have been able to discriminate not only G-quadruplex vs. duplex DNA structures, but also different G-quadruplex conformations on the glass beads by confocal microscopy.

Tumor-targeting delivery of herb-based drugs with cell-penetrating/tumor-targeting peptide-modified nanocarriers

Cancer has become one of the leading causes of mortality globally. The major challenges of conventional cancer therapy are the failure of most chemotherapeutic agents to accumulate selectively in tumor cells and their severe systemic side effects. In the past three decades, a number of drug delivery approaches have been discovered to overwhelm the obstacles. Among these, nanocarriers have gained much attention for their excellent and efficient drug delivery systems to improve specific tissue/organ/cell targeting. In order to enhance targeting efficiency further and reduce limitations of nanocarriers, nanoparticle surfaces are functionalized with different ligands. Several kinds of ligand-modified nanomedicines have been reported. Cell-penetrating peptides (CPPs) are promising ligands, attracting the attention of researchers due to their efficiency to transport bioactive molecules intracellularly. However, their lack of specificity and in vivo degradation led to the development of newer types of CPP. Currently, activable CPP and tumor-targeting peptide (TTP)-modified nanocarriers have shown dramatically superior cellular specific uptake, cytotoxicity, and tumor growth inhibition. In this review, we discuss recent advances in tumor-targeting strategies using CPPs and their limitations in tumor delivery systems. Special emphasis is given to activable CPPs and TTPs. Finally, we address the application of CPPs and/or TTPs in the delivery of plant-derived chemotherapeutic agents.

3D-3-culture: A tool to unveil macrophage plasticity in the tumour microenvironment

The tumour microenvironment (TME) shapes disease progression and influences therapeutic response. Most aggressive solid tumours have high levels of myeloid cell infiltration, namely tumour associated macrophages (TAM). Recapitulation of the interaction between the different cellular players of the TME, along with the extracellular matrix (ECM), is critical for understanding the mechanisms underlying disease progression. This particularly holds true for prediction of therapeutic response(s) to standard therapies and interrogation of efficacy of TME-targeting agents. In this work, we explored a culture platform based on alginate microencapsulation and stirred culture systems to develop the 3D-3-culture, which entails the co-culture of tumour cell spheroids of non-small cell lung carcinoma (NSCLC), cancer associated fibroblasts (CAF) and monocytes. We demonstrate that the 3D-3-culture recreates an invasive and immunosuppressive TME, with accumulation of cytokines/chemokines (IL4, IL10, IL13, CCL22, CCL24, CXCL1), ECM elements (collagen type I, IV and fibronectin) and matrix metalloproteinases (MMP1/9), supporting cell migration and promoting cell-cell interactions within the alginate microcapsules. Importantly, we show that both the monocytic cell line THP-1 and peripheral blood-derived monocytes infiltrate the tumour tissue and transpolarize into an M2-like macrophage phenotype expressing CD68, CD163 and CD206, resembling the TAM phenotype in NSCLC. The 3D-3-culture was challenged with chemo- and immunotherapeutic agents and the response to therapy was assessed in each cellular component. Specifically, the macrophage phenotype was modulated upon treatment with the CSF1R inhibitor BLZ945, resulting in a decrease of the M2-like macrophages. In conclusion, the crosstalk between the ECM and tumour, stromal and immune cells in microencapsulated 3D-3-culture promotes the activation of monocytes into TAM, mimicking aggressive tumour stages. The 3D-3-culture constitutes a novel tool to study tumour-immune interaction and macrophage plasticity in response to external stimuli, such as chemotherapeutic and immunomodulatory drugs.

Organoids: An intermediate modeling platform in precision oncology

Cancer harbors variable heterogeneity and plasticity. Thus far, our comprehension is greatly based on cell lines, organoids, and patient-derived tumor xenografts (PDTXs). Organoids are a three-dimensional in vitro culture platform constructed from self-organizing stem cells. They can almost accurately recapitulate tumor heterogeneity and microenvironment "in a dish," which surpass established cell lines and are not as expensive and time-consuming as PDTXs. As an intermediate model, tumor organoids are also used to study the fundamental issues of tumorigenesis and metastasis. They are specifically applied for drug testing and stored as "living biobanks." In this review, we highlight the translational applications of organoid technologies in tumor research and precision medicine, discuss the advantages and limitations compared with other mentioned methods, and provide our outlook on its future.

Combining 2D angiogenesis and 3D osteosarcoma microtissues to improve vascularization

Angiogenesis is now well known for being involved in tumor progression, aggressiveness, emergence of metastases, and also resistance to cancer therapies. In this study, to better mimic tumor angiogenesis encountered in vivo, we used 3D culture of osteosarcoma cells (MG-63) that we deposited on 2D endothelial cells (HUVEC) grown in monolayer. We report that endothelial cells combined with tumor cells were able to form a well-organized network, and that tubule-like structures corresponding to new vessels infiltrate tumor spheroids. These vessels presented a lumen and expressed specific markers as CD31 and collagen IV. The combination of 2D endothelial cells and 3D microtissues of tumor cells also increased expression of angiogenic factors as VEGF, CXCR4 and ICAM1. The cell environment is the key point to develop tumor vascularization in vitro and to be closer to tumor encountered in vivo.