Irinotecan and its active metabolite, SN-38: review of bioanalytical methods and recent update from clinical pharmacology perspectives

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

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

Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) methods for the therapeutic drug monitoring of cytotoxic anticancer drugs: An update

In the era of precision medicine, there is increasing evidence that conventional cytotoxic agents may be suitable candidates for therapeutic drug monitoring (TDM)- guided drug dosage adjustments and patient's tailored personalization of non-selective chemotherapies. To that end, many liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) assays have been developed for the quantification of conventional cytotoxic anticancer chemotherapies, that have been comprehensively and critically reviewed. The use of stable isotopically labelled internal standards (IS) of cytotoxic drugs was strikingly uncommon, accounting for only 48 % of the methods found, although their use could possible to suitably circumvent patients' samples matrix effects variability. Furthermore, this approach would increase the reliability of cytotoxic drug quantification in highly multi-mediated cancer patients with complex fluctuating pathophysiological and clinical conditions. LC-MS/MS assays can accommodate multiplexed analyses of cytotoxic drugs with optimal selectivity and specificity as well as short analytical times and, when using stable-isotopically labelled IS for quantification, provide concentrations measurements with a high degree of certainty. However, there are still organisational, pharmacological, and medical constraints to tackle before TDM of cytotoxic drugs can be more largely adopted in the clinics for contributing to our ever-lasting quest to improve cancer treatment outcomes.

Astraoleanosides E-P, oleanane-type triterpenoid saponins from the aerial parts of Astragalus membranaceus Bunge and their β-glucuronidase inhibitory activity

Historically, Astragalus membranaceus Bunge has been used as a beneficial medicinal plant, particularly in the Asian traditional medical systems, for the treatment of various human diseases such as stomach ulcers, diarrhea, and respiratory issues associated with phlegm. In this study, a phytochemical characterization of the aerial parts of A. membranaceusled to the isolation of 29 oleanane-type triterpenoid saponins, including 11 new compounds named astraoleanosides E-P (6-9, 13, 14, 18-22), as well as 18 known ones. The structures of these compounds were elucidated using nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry. Among them, astraoleanoside H (9) and cloversaponin III (15) demonstrated the most potent β-glucuronidase inhibitory activities, with IC50 values of 21.20 ± 0.75 and 9.05 ± 0.47 µM, respectively, compared to the positive control d-saccharic acid 1,4-lactone (IC50 = 20.62 ± 1.61 µM). Enzyme kinetics studies were then conducted to investigate the type of inhibition exhibited by these active compounds. In addition, the binding mechanism, key interactions, binding stability, and dynamic behavior of protein-ligand complexes were investigated through in silico approaches, such as molecular docking and molecular dynamics simulations. These findings highlight the promising potential of triterpenoid saponins from A. membranaceus as lead compounds for β-glucuronidase inhibitors, offering new possibilities for the development of therapeutic agents targeting various diseases where β-glucuronidase plays a crucial role.

Discovering New Substrates of a UDP-Glycosyltransferase with a High-Throughput Method

UDP-glycosyltransferases (UGTs) form a large enzyme family that is found in a wide range of organisms. These enzymes are known for accepting a wide variety of substrates, and they derivatize xenobiotics and metabolites for detoxification. However, most UGT homologs have not been well characterized, and their potential for biomedical and environmental applications is underexplored. In this work, we have used a fluorescent assay for screening substrates of a plant UGT homolog by monitoring the formation of UDP. We optimized the assay such that it could be used for high-throughput screening of substrates of the Medicago truncatula UGT enzyme, UGT71G1, and our results show that 34 of the 159 screened compound samples are potential substrates. With an LC-MS/MS method, we confirmed that three of these candidates indeed were glycosylated by UGT71G1, which includes bisphenol A (BPA) and 7-Ethyl-10-hydroxycamptothecin (SN-38); derivatization of these toxic compounds can lead to new environmental and medical applications. This work suggests that UGT homologs may recognize a substrate profile that is much broader than previously anticipated. Additionally, it demonstrates that this screening method provides a new means to study UDP-glycosyltransferases, facilitating the use of these enzymes to tackle a wide range of problems.

Local administration of irinotecan using an implantable drug delivery device stops high-grade glioma tumor recurrence in a glioblastoma tumor model

The treatment for Glioblastoma is limited due to the presence of the blood brain barrier, which restricts the entry of chemotherapeutic drugs into the brain. Local delivery into the tumor resection margin has the potential to improve efficacy of chemotherapy. We developed a safe and clinically translatable irinotecan implant for local delivery to increase its efficacy while minimizing systemic side effects. Irinotecan-loaded implants were manufactured using hot melt extrusion, gamma sterilized at 25 kGy, and characterized for their irinotecan content, release, and drug diffusion. Their therapeutic efficacy was evaluated in a patient-derived xenograft mouse resection model of glioblastoma. Their safety and translatability were evaluated using histological analysis of brain tissue and serum chemistry analysis. Implants containing 30% and 40% w/w irinotecan were manufactured without plasticizer. The 30% and 40% implants showed moderate local toxicity up to 2- and 6-day post-implantation. Histopathology of the implantation site showed signs of necrosis at days 45 and 14 for the 30% and 40% implants. Hematological analysis and clinical chemistry showed no signs of serious systemic toxicity for either implant. The 30% implants had an 80% survival at day 148, with no sign of tumor recurrence. Gamma sterilization and 12-month storage had no impact on the integrity of the 30% implants. This study demonstrates that the 30% implants are a promising novel treatment for glioblastoma that could be quickly translated into the clinic.

Attenuation of Type IV pili activity by natural products

The virulence factor Type IV pili (T4P) are surface appendages used by the opportunistic pathogen Pseudomonas aeruginosa for twitching motility and adhesion in the environment and during infection. Additionally, the use of these appendages by P. aeruginosa for biofilm formation increases its virulence and drug resistance. Therefore, attenuation of the activity of T4P would be desirable to control P. aeruginosa infections. Here, a computational approach has been pursued to screen natural products that can be used for this purpose. PilB, the elongation ATPase of the T4P machinery in P. aeruginosa, has been selected as the target subunit and virtual screening of FDA-approved drugs has been conducted. Screening identified two natural compounds, ergoloid and irinotecan, as potential candidates for inhibiting this T4P-associated ATPase in P. aeruginosa. These candidate compounds underwent further rigorous evaluation through molecular dynamics (MD) simulations and then through in vitro twitching motility and biofilm inhibition assays. Notably, ergoloid emerged as a particularly promising candidate for weakening the T4P activity by inhibiting the elongation ATPases associated with T4P. This repurposing study paves the way for the timely discovery of antivirulence drugs as an alternative to classical antibiotic treatments to help combat infections caused by P. aeruginosa and related pathogens.Communicated by Ramaswamy H. Sarma.

A dual catalytic functionalized hollow mesoporous silica-based nanocarrier coated with bacteria-derived exopolysaccharides for targeted delivery of irinotecan to colorectal cancer cells

In this study, we introduced a multifunctional hollow mesoporous silica-based nanocarrier (HMSN) for the targeted delivery of irinotecan (IRT) to colorectal cancer cells. Due to their large reservoirs, hollow mesoporous silica nanoparticles are suitable platforms for loading significant amounts of drugs for sustained drug release. To respond to pH and redox, HMSNs were functionalized with cerium and iron oxides. Additionally, they were coated with bacterial-derived exopolysaccharide (EPS) as a biocompatible polymer. In vitro analyses revealed that cytotoxicity induced in cancer cells through oxidative stress, mediated by mature nanocarriers (EPS.IRT.Ce/Fe.HMSN), was surprisingly greater than that caused by free drugs. Cerium and iron ions, in synergy with the drug, were found to generate reactive oxygen species when targeting the acidic pH within lysosomes and the tumor microenvironment. This, in turn, triggered cascade reactions, leading to cell death. In vivo experiments revealed that the proposed nanocarriers had no noticeable effect on healthy tissues. These findings indicate the selective delivery of the drug to cancerous tissue and the induction of antioxidant effects due to the dual catalytic properties of cerium in normal cells. Accordingly, this hybrid drug delivery system provides a more effective treatment for colorectal cancer with the potential for cost-effective scaling up.

Orally Administered Drugs and Their Complicated Relationship with Our Gastrointestinal Tract

Orally administered compounds represent the great majority of all pharmaceutical compounds produced for human use and are the most popular among patients since they are practical and easy to self-administer. Following ingestion, orally administered drugs begin a "perilous" journey down the gastrointestinal tract and their bioavailability is modulated by numerous factors. The gastrointestinal (GI) tract anatomy can modulate drug bioavailability and accounts for interpatient drug response heterogeneity. Furthermore, host genetics is a contributor to drug bioavailability modulation. Importantly, a component of the GI tract that has been gaining notoriety with regard to drug treatment interactions is the gut microbiota, which shares a two-way interaction with pharmaceutical compounds in that they can be influenced by and are able to influence administered drugs. Overall, orally administered drugs are a patient-friendly treatment option. However, during their journey down the GI tract, there are numerous host factors that can modulate drug bioavailability in a patient-specific manner.

Advances in non-radioactive PSMA-targeted small molecule-drug conjugates in the treatment of prostate cancer

Most patients with advanced prostate cancer (PCa) will develop metastatic castration-resistant prostate cancer (mCRPC) after androgen deprivation therapy, at this time the tumor enters the end stage, and the clinical treatment is very complicated, which requires rationalization of drugs to prolong the life of patients while improving their quality of life. Prostate-specific membrane antigen (PSMA) is a promising biological target for drug delivery in mCRPC due to its high level of specific expression in PCa cell membranes and low expression in normal tissues. Non-radioactive PSMA-targeted small molecule-drug conjugates (SMDCs) are gradually becoming a heat of discovery due to their good affinity and specificity; simple synthesis steps and transport management methods. Non-radioactive PSMA-targeted SMDCs under investigation can be divided into two categories: SMDCs and dual-ligand coupled drugs, among which SMDCs are the most widespread form of this type of conjugate. SMDCs have three key components: cytotoxic load, linker, and small molecule targeting ligands. SMDCs are internalized into the cell after binding to PSMA on the cell membrane and stored in endosomes and lysosomes, where they are usually enzymatically cleaved to allow precise release of cytotoxic molecules and uniform diffusion into the tumor tissue. More than a dozen non-radioactive PSMA-targeted SMDCs have been developed, many of which have shown favorable properties in both in vitro and in vivo evaluations, demonstrating more favorable results than unmodified cytotoxic drugs. Therefore, non-radioactive PSMA-targeted SMDCs have great therapeutic potential for mCRPC as a form of targeted therapy.

Replicative stress in gastroesophageal cancer is associated with chromosomal instability and sensitivity to DNA damage response inhibitors

Gastroesophageal adenocarcinoma (GEA) is an aggressive malignancy with chromosomal instability (CIN). To understand adaptive responses enabling DNA damage response (DDR) and CIN, we analyzed matched normal, premalignant, and malignant gastric lesions from human specimens and a carcinogen-induced mouse model, observing activation of replication stress, DDR, and p21 in neoplastic progression. In GEA cell lines, expression of DDR markers correlated with ploidy abnormalities, such as number of high-level focal amplifications and whole-genome duplication (WGD). Integrating TP53 status, ploidy abnormalities, and DDR markers into a compositive score helped predict GEA cell lines with enhanced sensitivity to Chk1/2 and Wee1 inhibition, either alone or combined with irinotecan (SN38). We demonstrate that Chk1/2 or Wee1 inhibition combined with SN38/irinotecan shows greater anti-tumor activity in human gastric cancer organoids and an in vivo xenograft mouse model. These findings indicate that specific DDR biomarkers and ploidy abnormalities may predict premalignant progression and response to DDR pathway inhibitors.

Pectin a multifaceted biopolymer in the management of cancer: A review

This review article focuses on the multifaceted roles of pectin in cancer management, namely as an oncotherapeutic delivery vehicle and a pharmacological agent. Over the past decades, the potential of pectin as a novel therapeutical agent for the prevention and/or management of cancer has gained increasing interest. Pectin has been found to modulate different mechanisms involved in the onset and progression of carcinogenesis, such as galectin-3 inhibition, caspase-3-induced apoptosis, and autophagy. Elucidating the structure-activity relationship provides insight into the relationship between the structure of pectin and different mechanism/s. The bioactivity of pectin, with respect to its structure, was critically discussed to give a better insight of the relationship between the structure of the extracted pectin and the observed bioactive effects. The rhamnogalacturonan I part of the pectin chain was found to bind to galectin-3, associated with several cancer hallmarks. The anti-inflammatory and antioxidant potential of pectin were also described. The roles of pectin as a treatment enhancer and a drug delivery vehicle for oncotherapeutics were critically defined. The scientific findings presented in this paper are expected to highlight the potential and role of pectin recovered from various plant sources in preventing and managing cancer.

Understanding the promising role of antibody drug conjugates in breast and ovarian cancer

A nascent category of anticancer therapeutic drugs called antibody-drug conjugates (ADCs) relate selectivity of aimed therapy using chemotherapeutic medicines with high cytotoxic power. Progressive linker technology led to the advancement of more efficacious and safer treatments. It offers neoteric as well as encouraging therapeutic strategies for treating cancer. ADCs selectively administer a medication by targeting antigens which are abundantly articulated on the membrane surface of tumor cells. Tumor-specific antigens are differently expressed in breast and ovarian cancers and can be utilized to direct ADCs. Compared to conventional chemotherapeutic drugs, this approach enables optimal tumor targeting while minimizing systemic damage. A cleavable linker improves the ADCs because it allows the toxic payload to be distributed to nearby cells that do not express the target protein, operating on assorted tumors with dissimilar cell aggregation. Presently fifteen ADCs are being studied in breast and ovarian carcinoma preclinically, and assortment of few have already undergone promising early-phase clinical trial testing. Furthermore, Phase I and II studies are investigating a wide variety of ADCs, and preliminary findings are encouraging. An expanding sum of ADCs will probably become feasible therapeutic choices as solo agents or in conjunction with chemotherapeutic agents. This review accentuates the most recent preclinical findings, pharmacodynamics, and upcoming applications of ADCs in breast and ovarian carcinoma.

Antibody drug conjugates: hitting the mark in pancreatic cancer?

Pancreatic cancer is one of the most common causes of cancer-related death, and the 5-year survival rate has only improved marginally over the last decade. Late detection of the disease means that in most cases the disease has advanced locally and/or metastasized, and curative surgery is not possible. Chemotherapy is still the first-line treatment however, this has only had a modest impact in improving survival, with associated toxicities. Therefore, there is an urgent need for targeted approaches to better treat pancreatic cancer, while minimizing treatment-induced side-effects. Antibody drug conjugates (ADCs) are one treatment option that could fill this gap. Here, a monoclonal antibody is used to deliver extremely potent drugs directly to the tumor site to improve on-target killing while reducing off-target toxicity. In this paper, we review the current literature for ADC targets that have been examined in vivo for treating pancreatic cancer, summarize current and on-going clinical trials using ADCs to treat pancreatic cancer and discuss potential strategies to improve their therapeutic window.

Fluorescence Lifetime Nanoscopy of Liposomal Irinotecan Onivyde: From Manufacturing to Intracellular Processing

Onivyde was approved by the Food and Drug Administration (FDA) in 2015 for the treatment of solid tumors, including metastatic pancreatic cancer. It is designed to encapsulate irinotecan at high concentration, increase its blood-circulation lifetime, and deliver it to cells where it is enzymatically converted into SN-38, a metabolite with 100- to 1000-fold higher anticancer activity. Despite a rewarding clinical path, little is known about the physical state of encapsulated irinotecan within Onivyde and how this synthetic identity changes throughout the process from manufacturing to intracellular processing. Herein, we exploit irinotecan intrinsic fluorescence and fluorescence lifetime imaging microscopy (FLIM) to selectively probe the supramolecular organization of the drug. FLIM analysis on the manufacturer's formulation reveals the presence of two coexisting physical states within Onivyde liposomes: (i) gelated/precipitated irinotecan and (ii) liposome-membrane-associated irinotecan, the presence of which is not inferable from the manufacturer's indications. FLIM in combination with high-performance liquid chromatography (HPLC) and a membrane-impermeable dynamic quencher of irinotecan reveals rapid (within minutes) and complete chemical dissolution of the gelated/precipitated phase upon Onivyde dilution in standard cell-culturing medium with extensive leakage of the prodrug from liposomes. Indeed, confocal imaging and cell-proliferation assays show that encapsulated and nonencapsulated irinotecan formulations are similar in terms of cell-uptake mechanism and cell-division inhibition. Finally, 2-channel FLIM analysis discriminates the signature of irinotecan from that of its red-shifted SN-38 metabolite, demonstrating the appearance of the latter as a result of Onivyde intracellular processing. The findings presented in this study offer fresh insights into the synthetic identity of Onivyde and its transformation from production to in vitro administration. Moreover, these results serve as another validation of the effectiveness of FLIM analysis in elucidating the supramolecular organization of encapsulated fluorescent drugs. This research underscores the importance of leveraging advanced imaging techniques to deepen our understanding of drug formulations and optimize their performance in delivery applications.

Discovery of VIP236, an αvβ3-Targeted Small-Molecule-Drug Conjugate with Neutrophil Elastase-Mediated Activation of 7-Ethyl Camptothecin Payload for Treatment of Solid Tumors

The emerging field of small-molecule-drug conjugates (SMDCs) using small-molecule biomarker-targeted compounds for tumor homing may provide new perspectives for targeted delivery. Here, for the first time, we disclose the structure and the synthesis of VIP236, an SMDC designed for the treatment of metastatic solid tumors by targeting αvβ3 integrins and extracellular cleavage of the 7-ethyl camptothecin payload by neutrophil elastase in the tumor microenvironment. Imaging studies in the Lewis lung mouse model using an elastase cleavable quenched substrate showed pronounced elastase activity in the tumor. Pharmacokinetics studies of VIP236 in tumor-bearing mice demonstrated high stability of the SMDC in plasma and high tumor accumulation of the cleaved payload. Studies in bile-duct-cannulated rats showed that biliary excretion of the unmodified conjugate is the primary route of elimination. Treatment- and time-dependent phosphorylation of H2AX, a marker of DNA damage downstream of topoisomerase 1 inhibition, verified the on-target activity of the payload cleaved from VIP236 in vivo. Treatment with VIP236 resulted in long-lasting tumor regression in subcutaneous patient-derived xenograft (PDX) models from patients with non-small-cell lung, colon, and renal cancer as well as in two orthotopic metastatic triple-negative breast cancer PDX models. In these models, a significant reduction of brain and lung metastases also was observed.

Intranasal delivery of nanoliposomal SN-38 for treatment of diffuse midline glioma

OBJECTIVE

Diffuse midline gliomas, including diffuse intrinsic pontine gliomas (DIPGs), are among the most malignant and devastating childhood brain cancers. Despite aggressive treatment, nearly all children with these tumors succumb to their disease within 2 years of diagnosis. Due to the anatomical location of the tumors within the pons, surgery is not a treatment option, and distribution of most systematically administered drugs is limited by the blood-brain barrier (BBB). New drug delivery systems that bypass the BBB are desperately needed to improve outcomes of DIPG patients. Intranasal delivery (IND) is a practical and noninvasive drug delivery system that bypasses the BBB and delivers the drugs to the brain through the olfactory and trigeminal neural pathways. In this study, the authors evaluated the efficacy of nanoliposomal (LS) irinotecan (CPT-11) and an active metabolite of CPT-11, 7-ethyl-10-hydroxycamptothecin (SN-38), using IND in DIPG patient-derived xenograft models.

METHODS

In vitro responses to LS-CPT-11 and LS-SN-38 in DIPG cells were evaluated with cell viability, colony formation, and apoptosis assays. The cellular uptakes of rhodamine-PE (Rhod)-labeled LS-CPT-11 and LS-SN-38 were analyzed with fluorescence microscopy. Mice bearing DIPG patient-derived xenografts were treated with IND of LS-control (empty liposome), LS-CPT-11, or LS-SN-38 by IND for 4 weeks. In vivo responses were measured for tumor growth by serial bioluminescence imaging and animal subject survival. The concentration of SN-38 in the brainstem tumor administered by IND was determined by liquid chromatography-mass spectrometry (LC-MS). Immunohistochemical analyses of the proliferative and apoptotic responses of in vivo tumor cells were performed with Ki-67 and TUNEL staining.

RESULTS

LS-SN-38 inhibited DIPG cell growth and colony formation and increased apoptosis, outperforming LS-CPT-11. Rhod-labeled LS-SN-38 showed intracellular fluorescence signals beginning at 30 minutes and peaking at 24 hours following treatment. LC-MS analysis revealed an SN-38 concentration in the brainstem tumor of 0.66 ± 0.25 ng/ml (5.43% ± 0.31% of serum concentration). IND of LS-SN-38 delayed tumor growth and significantly prolonged animal survival compared with IND of LS-control (p < 0.0001) and LS-CPT-11 (p = 0.003). IND of LS-SN-38 increased the number of TUNEL-positive cells and decreased the Ki-67-positive cells in the brainstem tumor.

CONCLUSIONS

This study demonstrates that IND of LS-SN-38 bypasses the BBB and enables efficient and noninvasive drug delivery to the brainstem tumor, providing a promising therapeutic approach for treating DIPG.

Antibody drug conjugates as targeted cancer therapy: past development, present challenges and future opportunities

Antibody drug conjugates (ADCs) are promising cancer therapeutics with minimal toxicity as compared to small cytotoxic molecules alone and have shown the evidence to overcome resistance against tumor and prevent relapse of cancer. The ADC has a potential to change the paradigm of cancer chemotherapeutic treatment. At present, 13 ADCs have been approved by USFDA for the treatment of various types of solid tumor and haematological malignancies. This review covers the three structural components of an ADC-antibody, linker, and cytotoxic payload-along with their respective structure, chemistry, mechanism of action, and influence on the activity of ADCs. It covers comprehensive insight on structural role of linker towards efficacy, stability & toxicity of ADCs, different types of linkers & various conjugation techniques. A brief overview of various analytical techniques used for the qualitative and quantitative analysis of ADC is summarized. The current challenges of ADCs, such as heterogeneity, bystander effect, protein aggregation, inefficient internalization or poor penetration into tumor cells, narrow therapeutic index, emergence of resistance, etc., are outlined along with recent advances and future opportunities for the development of more promising next-generation ADCs.

Replicative stress in gastroesophageal adenocarcinoma is associated with chromosomal instability and sensitivity to DNA damage response inhibitors

Gastroesophageal adenocarcinoma (GEA) is an aggressive, often lethal, malignancy that displays marked chromosomal instability (CIN). To understand adaptive responses that enable CIN, we analyzed paired normal, premalignant, and malignant gastric lesions from human specimens and a carcinogen-induced mouse model, observing activation of replication stress, DNA damage response (DDR), and cell cycle regulator p21 in neoplastic progression. In GEA cell lines, expression of DDR markers correlated with ploidy abnormalities, including high-level focal amplifications and whole-genome duplication (WGD). Moreover, high expression of DNA damage marker H2AX correlated with CIN, WGD, and inferior patient survival. By developing and implementing a composite diagnostic score that incorporates TP53 mutation status, ploidy abnormalities, and H2AX expression, among other genomic information, we can identify GEA cell lines with enhanced sensitivity to DDR pathway inhibitors targeting Chk1/2 and Wee1. Anti-tumor properties were further augmented in combination with irinotecan (SN38) but not gemcitabine chemotherapy. These results implicate specific DDR biomarkers and ploidy abnormalities as diagnostic proxy that may predict premalignant progression and response to DDR pathway inhibitors.

Targeting efficacy and anticancer activity of polymeric nanoparticles of SN-38 on colon cancer cell lines

Background

Colorectal cancer is the third most prevailing cancer in the whole world. Chemotherapeutic agents which are used for treatment have severe side effects and also have unwanted exposure to healthy cells. In the present study, polymeric nanoparticles of SN-38 were prepared (using cationic and anionic polymers). They were optimized by Box Behnken design and characterized for its physicochemical properties and in vitro drug release. Optimized formulation (CsENP) was evaluated for its targeting efficacy by Gamma Scintigraphy studies on Swiss Albino mice and in vitro Cytotoxic assay against colon cancer cell line, viz. HT-29.

Results

The images of Whole body gamma scintigraphy imaging of Swiss Albino mice show that CsENP remained intact till 2 h and after that at 4 h imaging it started dispersing and releasing drug which continued till 20 h. In Organ distribution studies, no radioactivity was traced in heart from the formulation. Even in liver, spleen, kidney and lung trace radioactivity was seen after 6 h. In case of CsENP radioactivity was seen in small intestine after 2 h and maximum (87.8% radioactivity) is seen in colon and rectum area after 4 h. At equivalent concentrations, the in vitro cell viability of HT-29 cells after 72 h incubation time showed that CsENP have enhanced cytotoxicity.

Conclusions

The results obtained of Whole body gamma scintigraphy imaging and organ distribution of Swiss Albino mice show that CsENP is Colon targeting and was found to be effective against colon cancer cell lines.

Cerebrolysin Alleviating Effect on Glutamate-Mediated Neuroinflammation Via Glutamate Transporters and Oxidative Stress

Glutamate, one of the most important excitatory neurotransmitters, acts as a signal transducer in peripheral tissues and endocrine cells. Excessive glutamate secretion has been shown to cause excitotoxicity and neurodegenerative disease. Cerebrolysin is a mixture of enzymatically treated peptides derived from pig brain including neurotrophic factors, like brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), and ciliary neurotrophic factor (CNTF). The present study investigated the protective effects of cerebrolysin on glutamate transporters (EAAT 1, EAAT 2) and cytokines (IL-1β and IL-10) activity in glutamate-mediated neurotoxicity. Primary cortex neuron culture was exposed to glutamate and successively treated with various cerebrolysin concentrations for 24 and 48 h. Our data showed that cerebrolysin primarily protects neurons by decreasing glutamate concentration in the synaptic cleft. In addition, Cerebrolysin can decrease oxidative stress and neuron cell damage by increasing antioxidant activity and decreasing inflammation cytokine levels.

Dual-Functionalized Nanoliposomes Achieve a Synergistic Chemo-Phototherapeutic Effect

The enhancement of photodynamic therapy (PDT) effectiveness by combining it with other treatment modalities and improved drug delivery has become an interesting field in cancer research. We have prepared and characterized nanoliposomes containing the chemotherapeutic drug irinotecan (CPT11_lip), the photodynamic agent protoporphyrin IX (PpIX_lip), or their combination (CPT11-PpIX_lip). The effects of individual and bimodal (chemo-phototherapeutic) treatments on HeLa cells have been studied by a combination of biological and photophysical studies. Bimodal treatments show synergistic cytotoxic effects on HeLa cells at relatively low doses of PpIX/PDT and CPT11. Mechanistic cell inactivation studies revealed mitotic catastrophe, apoptosis, and senescence contributions. The enhanced anticancer activity is due to a sustained generation of reactive oxygen species, which increases the number of double-strand DNA breaks. Bimodal chemo-phototherapeutic liposomes may have a very promising future in oncological therapy, potentially allowing a reduction in the CPT11 concentration required to achieve a therapeutic effect and overcoming resistance to individual cancer treatments.

SN-38 Sensitizes BRCA-Proficient Ovarian Cancers to PARP Inhibitors through Inhibiting Homologous Recombination Repair

As a multifunctional protein posttranslational modification enzyme in eukaryotic cells, Poly-ADP-ribose polymerase (PARP) acts as a DNA damage sensor, which helps to repair DNA damage through recruiting repair proteins to the DNA break sites. PARP inhibitors offer a significant clinical benefit for ovarian cancer with BRCA1/2 mutations. However, the majority of ovarian cancer patients harbor wild-type (WT) BRCA1/2 status, which narrows its clinical application. Here, we identified a small compound, SN-38, a CPT analog, which sensitizes BRCA-proficient ovarian cancer cells to PARP inhibitor treatment by inhibiting homologous recombination (HR) repair. SN-38 treatment greatly enhanced PARP inhibitor olaparib induced DNA double-strand breaks (DSBs) and DNA replication stress. Meanwhile, the combination of SN-38 and olaparib synergistically induced apoptosis in ovarian cancer. Furthermore, combination administration of SN-38 and olaparib induced synergistic antitumor efficacy in an ovarian cancer xenograft model in vivo. Therefore, our study provides a novel therapeutic strategy to optimize PARP inhibitor therapy for patients with BRCA-proficient ovarian cancer.

Actively targeted delivery of SN38 by ultrafine iron oxide nanoparticle for treating pancreatic cancer

Pancreatic cancer remains one of the most lethal cancers largely due to the inefficient delivery of therapeutics. Nanomaterials have been extensively investigated as drug delivery platforms, showing improved drug pharmacodynamics and pharmacokinetics. However, their applications in pancreatic cancer have not yet been successful due to limited tumor delivery caused by dense tumor stroma and distorted tumor vasculatures. Meanwhile, smaller-sized nanomaterials have shown improved tumor delivery and retention in various tumors, including pancreatic tumors, suggesting their potential in enhancing drug delivery. An ultrafine iron oxide nanoparticle (uIONP) was used to encapsulate 7-ethyl-10-hydroxyl camptothecin (SN38), the water-insoluble active metabolite of pancreatic cancer chemotherapy drug irinotecan. Insulin-like growth factor 1 (IGF-1) was conjugated to uIONP as a ligand for targeting pancreatic cancer cells overexpressing IGF-1 receptor (IGF1R). The SN38 loading and release profile were characterized. The pancreatic cancer cell targeting using IGF1-uIONP/SN38 and subsequently induced cell apoptosis were also investigated. IGF1-uIONP/SN38 demonstrated a stable drug loading in physiological pH with the loading efficiency of 68.2 ± 3.5% (SN38/Fe, wt%) and < 7% release for 24 h. In tumor-interstitial- and lysosomal-mimicking pH (6.5 and 5.5), 52.2 and 91.3% of encapsulated SN38 were released over 24 h. The IGF1-uIONP/SN38 exhibited specific receptor-mediated cell targeting and cytotoxicity Ato MiaPaCa-2 and Panc02 pancreatic cancer cells with IC50 of 11.8 ± 2.3 and 20.8 ± 3.5 nM, respectively, but not to HEK293 human embryonic kidney cells. IGF1-uIONP significantly improved the targeted SN38 delivery to pancreatic cancer cells, holding the potential for in vivo theranostic applications.

Identification of environmental chemicals that activate p53 signaling after in vitro metabolic activation

Currently, approximately 80,000 chemicals are used in commerce. Most have little-to-no toxicity information. The U.S. Toxicology in the 21st Century (Tox21) program has conducted a battery of in vitro assays using a quantitative high-throughput screening (qHTS) platform to gain toxicity information on environmental chemicals. Due to technical challenges, standard methods for providing xenobiotic metabolism could not be applied to qHTS assays. To address this limitation, we screened the Tox21 10,000-compound (10K) library, with concentrations ranging from 2.8 nM to 92 µM, using a p53 beta-lactamase reporter gene assay (p53-bla) alone or with rat liver microsomes (RLM) or human liver microsomes (HLM) supplemented with NADPH, to identify compounds that induce p53 signaling after biotransformation. Two hundred and seventy-eight compounds were identified as active under any of these three conditions. Of these 278 compounds, 73 gave more potent responses in the p53-bla assay with RLM, and 2 were more potent in the p53-bla assay with HLM compared with the responses they generated in the p53-bla assay without microsomes. To confirm the role of metabolism in the differential responses, we re-tested these 75 compounds in the absence of NADPH or with heat-attenuated microsomes. Forty-four compounds treated with RLM, but none with HLM, became less potent under these conditions, confirming the role of RLM in metabolic activation. Further evidence of biotransformation was obtained by measuring the half-life of the parent compounds in the presence of microsomes. Together, the data support the use of RLM in qHTS for identifying chemicals requiring biotransformation to induce biological responses.

Tackling metastatic triple-negative breast cancer with sacituzumab govitecan

Introduction Metastatic triple-negative breast cancer (TNBC) is an aggressive cancer with poor survival that is difficult to treat due to a lack of targeted options. Conventional therapies targeting hormone receptors (HR) and human epidermal growth factor 2 (HER2) are ineffective and often chemotherapy is standard-of-care. Sacituzumab govitecan is an antibody drug conjugate (ADC) comprised of an active metabolite of irinotecan, SN-38, bound to a humanized monoclonal antibody targeting trophoblastic cell-surface antigen 2 (Trop-2). Trop-2 is highly expressed on the surface of TNBC cells, making it an attractive target. Areas covered We explore the mechanism, pharmacology, efficacy, safety, and tolerability of sacituzumab govitecan. A literature search was conducted via PubMed using keywords such as 'sacituzumab govitecan,' and 'metastatic TNBC.' Expert opinion Sacituzumab govitecan has promising survival benefits in patients with previously treated mTNBC based on data from the ASCENT trial. Common adverse effects were neutropenia, diarrhea, and nausea, however these effects were manageable with supportive care. Sacituzumab govitecan has shown promise in cancers outside of TNBC, such as urothelial and lung and is being evaluated in HR-positive breast cancers. It is likely we will see this therapy used in combination with other novel targeted agents as current clinical trials mature.

Dimeric Artesunate-Phosphatidylcholine-Based Liposomes for Irinotecan Delivery as a Combination Therapy Approach

In this work, dimeric artesunate-phosphatidylcholine conjugate (dARTPC)-based liposomes encapsulated with irinotecan (Ir) were developed for anticancer combination therapy. First, dARTPC featured with unique amphipathic properties formed liposomes by classical thin-film methods. After that, Ir was encapsulated into dARTPC-based liposomes (Ir/dARTPC-LP) by the triethylammonium sucrose octasulfate gradient method. Physicochemical characterization indicated that Ir/dARTPC-LP had a mean size of around 140 nm and a negative ζ potential of approximately -30 mV. Most noticeably, liposomes displayed an encapsulation efficiency of greater than 98% with a controllable drug loading of 4-22%. The in vitro release of dihydroartemisinin (DHA) and Ir from Ir/dARTPC-LP was investigated by dialysis in different media. It was found that effective release of both DHA (65.42%) and Ir (77.28%) in a weakly acidic medium (pH 5.0) after 48 h was achieved in comparison to very slow release under a neutral environment (DHA 9.90% and Ir 8.72%), indicating the controllable release of both drugs. Confocal laser scanning microscopy confirmed the improved cellular internalization of Ir/dARTPC-LP. The cytotoxicity of Ir/dARTPC-LP was evaluated in the MCF-7, A549, and HepG2 cell lines. The results showed that Ir/dARTPC-LP had significant synergistic efficacy in the loss of cell growth. In vivo anticancer evaluation was performed using a 4T1 xenograft tumor model. Ir/dARTPC-LP had a high tumor inhibition rate of 62.7% without significant toxicity in comparison with the injection of Ir solution. Taken together, dARTPC encapsulated with Ir has great potential for anticancer combination therapy.

Thermally induced silane dehydrocoupling on porous silicon nanoparticles for ultra-long-acting drug release

Here, we report an ultra-long-acting drug release nano-formulation based on porous silicon nanoparticles (pSiNPs) that are prepared by thermally induced silane dehydrocoupling and lipid-coating. This robust formulation offers the ability to release an anticancer drug, for up to 2 weeks, in various biological environments; pH 7.4 buffer, cancer cells, and tumor xenograft model.

UGT1A1 regulatory variant with potential effect on efficacy of HIV and cancer drugs commonly prescribed in South Africa

Aim: Despite the high disease burden of human immunodeficiency virus (HIV) infection and colorectal cancer (CRC) in South Africa (SA), treatment-relevant pharmacogenetic variants are understudied. Materials & methods: Using publicly available genotype and gene expression data, a bioinformatic pipeline was developed to identify liver expression quantitative trait loci (eQTLs). Results: A novel cis-eQTL, rs28967009, was identified for UGT1A1, which is predicted to upregulate UGT1A1 expression thereby potentially affecting the metabolism of dolutegravir and irinotecan, which are extensively prescribed in SA for HIV and colorectal cancer treatment, respectively. Conclusion: As increased UGT1A1 expression could affect the clinical outcome of dolutegravir and irinotecan treatment by increasing drug clearance, patients with the rs28967009A variant may require increased drug doses to reach therapeutic levels or should be prescribed alternative drugs.

SN38 loaded nanostructured lipid carriers (NLCs); preparation and in vitro evaluations against glioblastoma

SN38 is the active metabolite of irinotecan with 1000-fold greater cytotoxicity compared to the parent drug. Despite the potential, its application as a drug is still seriously limited due to its stability concerns and low solubility in acceptable pharmaceutical solvents. To address these drawbacks here nanostructured lipid carrier (NLC) containing SN38 was prepared and its cytotoxicity against U87MG glioblastoma cell line was investigated. The formulations were prepared using hot ultrasonication and solvent evaporation/emulsification methods. NLCs with a mean size of 140 nm and particle size distribution (PDI) of 0.25 were obtained. The average loading efficiency was 9.5% and its entrapment efficiency was 81%. In order to obtain an accurate determination of released amount of SN38 a novel medium and extraction method was designed, which lead to an appropriate in vitro release profile of the drug from the prepared NLCs. The MTT test results revealed the significant higher cytotoxicity of NLCs on U87MG human glioblastoma cell line compared with the free drug. The confocal microscopy images confirmed the proper penetration of the nanostructures into the cells within the first 4 h. Consequently, the results indicated promising potentials of the prepared NLCs as a novel treatment for glioblastoma.

Heterogenous chemosensitivity of a panel of organoid lines derived from small cell neuroendocrine carcinoma of the uterine cervix

Small cell neuroendocrine carcinoma (SCNEC) of the uterine cervix is a rare disease with a poor prognosis. The lack of established disease models has hampered therapy development. We generated a panel of cancer tissue-originated spheroid (CTOS) lines derived from SCNEC of the uterine cervix using a method based upon cell-cell contact throughout the preparation and culturing processes. Using 11 CTOS lines, we assessed the sensitivity of various drugs used in clinical practice. Drug sensitivity assays revealed significant heterogeneous inter-CTOS chemosensitivity. Microarray analyses were then performed to identify sensitivity-related gene signatures. Specific gene sets were identified which likely contribute to the sensitivity to the tested drugs. We identified a line (Cerv54) that was exceptionally sensitive to irinotecan. Cerv54 had increased levels of CES1, which catalyzes the conversion of irinotecan to the active form, SN38, although in Cerv54 cells, SN38 was undetectable, CES1 expression and activity were markedly low compared to the liver, and a CES1 inhibitor had no effect on irinotecan sensitivity. These results suggested a novel irinotecan mode of action in Cerv54. Our CTOS lines may be useful for understanding the variation and mechanism of drug sensitivity, contributing to the understanding and development of chemotherapeutic drugs.

A simple, rapid and low-cost spectrophotometric method for irinotecan quantification in human plasma and in pharmaceutical dosage forms

Irinotecan is an anticancer drug for which significant benefits from personalised dosing are expected. Quick procedures are therefore essential for monitoring irinotecan in treated patients. The objective of this work was to develop and validate a rapid and simple visible spectrophotometric method for quantitative determination of irinotecan in pharmaceutical dosage forms and to further investigate its usefulness for irinotecan analysis in plasma. Based on the shift of the irinotecan 355/368 nm-peak at very low pH (0.2) to 400 nm, we established a linear relationship between absorbance at 400 nm and irinotecan concentration in dilutions of an irinotecan solution for injection (R2 ≥ 0.999) and in plasma containing irinotecan (R2 ≥ 0.995). Background absorbance correction at 455 nm was essential to minimise background interference, solely in plasma samples. We fully validated the assay for quality control of the irinotecan solution in the injection dosage form: the standard curve was linear over the concentration range of 0.90 to at least 37.00 μg ml-1. The CV% on all quality control levels was determined to be ≤5.81% for repeatability and ≤6.62% for intermediate precision. Recovery was between 96.5% and 101.9%. Upon comparison with the LC/UV method, we demonstrated very good agreement and acceptable bias between the two methods (slope 0.973, y-intercept 0.0064). Similarly, the technical parameters of the assay in plasma satisfied international guidelines for method validation: the useful analytical range was determined to be between 0.93 and at least 10.00 μg ml-1. This is suitable for quantifying irinotecan in the plasma of treated patients, in the upper region of its therapeutic window, to decide whether dose adjustment is required. Repeatability and intermediate precision (CV%) were within 4.49% and 9.91%, respectively. Recovery was between 96.3% and 103.8%. There was a lack of significant interference by mild hemolysis or by icterus. Irinotecan extraction efficiency from plasma was within 77.9-68.5%. Our results indicated that the proposed method allows quantitative determination of irinotecan plasma levels with acceptable analytical characteristics. The advantages of the proposed method in both matrices, in terms of specificity, rapidity, simplicity, environmental impact and cost effectiveness, are discussed.

Computational estimation of potential inhibitors from known drugs against the main protease of SARS-CoV-2

The coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread worldwide recently, leading to global social and economic disruption. Although the emergently approved vaccine programs against SARS-CoV-2 have been rolled out globally, the number of COVID-19 daily cases and deaths has remained significantly high. Here, we attempt to computationally screen for possible medications for COVID-19 via rapidly estimating the highly potential inhibitors from an FDA-approved drug database against the main protease (Mpro) of SARS-CoV-2. The approach combined molecular docking and fast pulling of ligand (FPL) simulations that were demonstrated to be accurate and suitable for quick prediction of SARS-CoV-2 Mpro inhibitors. The results suggested that twenty-seven compounds were capable of strongly associating with SARS-CoV-2 Mpro. Among them, the seven top leads are daclatasvir, teniposide, etoposide, levoleucovorin, naldemedine, cabozantinib, and irinotecan. The potential application of these drugs in COVID-19 therapy has thus been discussed.

Approved drugs predicted to interact with critical residues in the substrate-binding site of SARS-CoV-2 Mpro can be promising inhibitors.

Synthesis and Biological Evaluation of 10-Substituted Camptothecin Derivatives with Improved Water Solubility and Activity

Despite remarkable clinical achievements, camptothecin (CPT) still suffers from poor solubility and severe toxicity. Therefore, it is necessary to redevelop CPT derivatives as supplementary antitumor agents with good water solubility and small side effects. In this work, 27 camptothecin derivatives were synthesized and screened for their cytotoxicity against A549 (lung) and HCT-116 (colon) cancer cell lines. Among them, compound B7, 7-ethyl-10-(2-oxo-2-(4-methylpiperidin-1-yl)ethoxy)camptothecin,was demonstrated in vitro to be a more potent antitumor agent than SN-38 by comparison of their inhibitory activities against cell proliferation and colony formation and interference effect on process of cell cycle and cell apoptosis. Additionally, a molecular docking model revealed that B7 can interact with the topoisomerase I-DNA complex, and that the solubility of B7 reached 5.73 μg/mL in water. Moreover, B7 significantly inhibited tumor growth in an A549 xenograft model at dosages of 0.4 and 2.0 mg/kg, and exhibited minimum lethal doses comparable to those of irinotecan. These results indicated that B7, with improved solubility, enhanced activity and acceptable acute toxicity, can be used as a lead compound for the development of novel anticancer agents.

One-pot synthesis of acid-degradable polyphosphazene prodrugs for efficient tumor chemotherapy

In order to improve the therapeutic efficacy and reduce the side effects of anticancer drugs, stimuli-responsive and biodegradable drug-delivery systems have attracted significant attention in the past three decades. Herein, we report acid-responsive and degradable polyphosphazene nano-prodrugs synthesized via a one-pot cross-linking reaction of 4-hydroxybenzhydrazide-modified doxorubicin (BMD) with hexachlorocyclotriphosphazene (HCCP). The phenol groups in the as-synthesized BMD exhibited a high reactivity towards HCCP and in the presence of a basic catalyst the determined drug loading ratio of the nanoparticles, denoted as HCCP-BMD, was up to 85.64%. Interestingly, the hydrazone bonds in BMD and the skeleton of polyphosphazene tended to break down in acidic environments, and the antitumor active drug DOX was found to be released in an acidic tumor microenvironment (pH ∼ 6.8 for extracellular, and pH ∼ 5.0 for endosomes and lysosomes). The resulting HCCP-BMD prodrug exhibited high cytotoxicity to HeLa cells and could effectively suppress tumor growth, with negligible damage to normal tissues. We therefore believe that this acid- degradable polyphosphazene prodrug may offer great potential in various biomedical fields.

DNA topoisomerases as molecular targets for anticancer drugs

The significant role of topoisomerases in the control of DNA chain topology has been confirmed in numerous research conducted worldwide. The prevalence of these enzymes, as well as the key importance of topoisomerase in the proper functioning of cells, have made them the target of many scientific studies conducted all over the world. This article is a comprehensive review of knowledge about topoisomerases and their inhibitors collected over the years. Studies on the structure-activity relationship and molecular docking are one of the key elements driving drug development. In addition to information on molecular targets, this article contains details on the structure-activity relationship of described classes of compounds. Moreover, the work also includes details about the structure of the compounds that drive the mode of action of topoisomerase inhibitors. Finally, selected topoisomerases inhibitors at the stage of clinical trials and their potential application in the chemotherapy of various cancers are described.

Pharmacovigilance of herb-drug interactions: A pharmacokinetic study on the combination administration of herbal Kang'ai injection and chemotherapy irinotecan hydrochloride injection by LC-MS/MS

Chinese herbal drugs are often combined with chemotherapy drugs for the treatment of cancers. However, the combination administrations often do not have scientifically sound bases established on full preclinical and clinical investigations. A commonly used anti-colon-cancer herb-drug pair, irinotecan (CPT-11) hydrochloride injection and Kang'ai (KA) injection was taken as an example to investigate the possible pharmacokinetic interactions between Chinese herbal drugs and chemotherapy injections to determine the potential adverse drug reactions (ADRs). Rats were randomly divided into three groups and received 20 mg/kg CPT-11 injection 15 min after administration of 4 mL/kg saline for the CPT-11 single administration group and 4 mL/kg KA injection for the separated co-administration group, respectively. In the pre-mixed co-administration group, rats received a mixture of 20 mg/kg CPT-11 injection and 4 mL/kg KA injection. Blood samples were collected at 10 pre-determined time points between 0 and 24 h. The tissue samples were collected at 5 and 8 min after the injections, respectively. A reliable LC-MS/MS method was established for the simultaneous determination of CPT-11 and its metabolites, SN-38, SN-38 G and APC in the rat plasma and tissue samples, after full confirmation of two injections chemical and stability compatibilities. Compared to the C₀ (5129 ± 757 ng/mL) and AUC_0-t (7858 ± 1307 ng h/mL) of CPT-11 in the CPT-11 single administration group, the C₀ (4574 ± 371 ng/mL) and AUC_0-t (8779 ± 601 ng h/mL) after the separated co-administration remained unchanged, but the pre-mixed co-administration resulted with a significant increased C₀ (29,454 ± 12,080 ng/mL) and AUC_0-t (15,539 ± 5165 ng h/mL) (p < 0.05). Since the exposures of CPT-11 in most tissues in the pre-mixed co-administration group were dramatically lower than the separated co-administration group, the increased CPT-11 plasma concentration may be produced by the delayed tissue distribution because of the encapsulation by the components contained in KA injection, such as polysaccharides. Similar differences were also found in its metabolite, SN-38 G. There are obvious herb-drug interactions between CPT-11 injection and KA injection after the pre-mixed co-administration. The resulting excessive CPT-11 in the plasma may lead to many serious ADRs. Therefore, the full evaluation of herb-drug interactions is necessary and inappropriate combinations should be avoided.

Role of gut microbiota in identification of novel TCM-derived active metabolites

Traditional Chinese Medicine (TCM) has been extensively used to ameliorate diseases in Asia for over thousands of years. However, owing to a lack of formal scientific validation, the absence of information regarding the mechanisms underlying TCMs restricts their application. After oral administration, TCM herbal ingredients frequently are not directly absorbed by the host, but rather enter the intestine to be transformed by gut microbiota. The gut microbiota is a microbial community living in animal intestines, and functions to maintain host homeostasis and health. Increasing evidences indicate that TCM herbs closely affect gut microbiota composition, which is associated with the conversion of herbal components into active metabolites. These may significantly affect the therapeutic activity of TCMs. Microbiota analyses, in conjunction with modern multiomics platforms, can together identify novel functional metabolites and form the basis of future TCM research.

Ultrasound-triggered therapeutic microbubbles enhance the efficacy of cytotoxic drugs by increasing circulation and tumor drug accumulation and limiting bioavailability and toxicity in normal tissues

Most cancer patients receive chemotherapy at some stage of their treatment which makes improving the efficacy of cytotoxic drugs an ongoing and important goal. Despite large numbers of potent anti-cancer agents being developed, a major obstacle to clinical translation remains the inability to deliver therapeutic doses to a tumor without causing intolerable side effects. To address this problem, there has been intense interest in nanoformulations and targeted delivery to improve cancer outcomes. The aim of this work was to demonstrate how vascular endothelial growth factor receptor 2 (VEGFR2)-targeted, ultrasound-triggered delivery with therapeutic microbubbles (thMBs) could improve the therapeutic range of cytotoxic drugs. Methods: Using a microfluidic microbubble production platform, we generated thMBs comprising VEGFR2-targeted microbubbles with attached liposomal payloads for localised ultrasound-triggered delivery of irinotecan and SN38 in mouse models of colorectal cancer. Intravenous injection into tumor-bearing mice was used to examine targeting efficiency and tumor pharmacodynamics. High-frequency ultrasound and bioluminescent imaging were used to visualise microbubbles in real-time. Tandem mass spectrometry (LC-MS/MS) was used to quantitate intratumoral drug delivery and tissue biodistribution. Finally, 89Zr PET radiotracing was used to compare biodistribution and tumor accumulation of ultrasound-triggered SN38 thMBs with VEGFR2-targeted SN38 liposomes alone. Results: ThMBs specifically bound VEGFR2 in vitro and significantly improved tumor responses to low dose irinotecan and SN38 in human colorectal cancer xenografts. An ultrasound trigger was essential to achieve the selective effects of thMBs as without it, thMBs failed to extend intratumoral drug delivery or demonstrate enhanced tumor responses. Sensitive LC-MS/MS quantification of drugs and their metabolites demonstrated that thMBs extended drug exposure in tumors but limited exposure in healthy tissues, not exposed to ultrasound, by persistent encapsulation of drug prior to elimination. 89Zr PET radiotracing showed that the percentage injected dose in tumors achieved with thMBs was twice that of VEGFR2-targeted SN38 liposomes alone. Conclusions: thMBs provide a generic platform for the targeted, ultrasound-triggered delivery of cytotoxic drugs by enhancing tumor responses to low dose drug delivery via combined effects on circulation, tumor drug accumulation and exposure and altered metabolism in normal tissues.

A brain tumor-homing tetra-peptide delivers a nano-therapeutic for more effective treatment of a mouse model of glioblastoma

Organ-specific cell-penetrating peptides (CPPs) are a class of molecules that can be highly effective at delivering therapeutic cargoes, and they are currently of great interest in cancer treatment strategies. Herein, we describe a new CPP (amino acid sequence serine-isoleucine-tyrosine-valine, or SIWV) that homes to glioblastoma multiforme (GBM) brain tumor tissues with remarkable specificity in vitro and in vivo. The SIWV sequence was identified from an isoform of annexin-A3 (AA3H), a membrane-interacting human protein. The mechanism of intracellular permeation is proposed to follow a caveolin-mediated endocytotic pathway, based on in vitro and in vivo receptor inhibition and genetic knockdown studies. Feasibility as a targeting agent for therapeutics is demonstrated in a GBM xenograft mouse model, where porous silicon nanoparticles (pSiNPs) containing the clinically relevant anticancer drug SN-38 are grafted with SIWV via a poly-(ethylene glycol) (PEG) linker. The formulation shows enhanced in vivo targeting ability relative to a formulation employing a scrambled control peptide, and significant (P < 0.05) therapeutic efficacy relative to free SN-38 in the GBM xenograft animal model.

A pharmacokinetic-pharmacodynamic model based on multi-organ-on-a-chip for drug-drug interaction studies

In drug discovery, the emergence of unexpected toxicity is often a problem resulting from a poor understanding of the pharmacokinetics of drug-drug interactions (DDI). Organ-on-a-chip (OoC) has been proposed as an in vitro model to evaluate drug efficacy and toxicity in pharmacology, but it has not been applied to DDI studies yet. In this study, we aim to evaluate whether organ-on-a-chip technologies can be applied to DDI studies. To assess the usefulness of OoC for DDI studies, we proposed a multi-organ-on-a-chip (MOoC) with a liver part as the metabolic model and a cancer part as the drug target model, and a pharmacokinetic-pharmacodynamic (PK-PD) model describing the MOoC. An anticancer prodrug, CPT-11, was used to evaluate the drug efficacy of the metabolite in the liver part of the MOoC. To evaluate DDI using the MOoC, the inhibitory effect of simvastatin and ritonavir on the metabolism of CPT-11 was tested. The DDI estimation method was evaluated by comparing the results of the concomitant administration experiment using the MOoC and the results of simulation using the proposed PK-PD model with the estimated parameters. The results were similar, suggesting that the combination of the PK-PD model and the MOoC is a useful way to predict DDI. We conclude that OoC technologies could facilitate a better understanding of pharmacokinetic mechanisms with DDI.

Development and in vivo evaluation of Irinotecan-loaded Drug Eluting Seeds (iDES) for the localised treatment of recurrent glioblastoma multiforme

Glioblastoma multiforme (GBM) is impossible to fully remove surgically and almost always recurs at the borders of the resection cavity, while systemic delivery of therapeutic drug levels to the brain tumour is limited by the blood-brain barrier. This research describes the development of a novel formulation of Irinotecan-loaded Drug Eluting Seeds (iDES) for insertion into the margin of the GBM resection cavity to provide a sustained high local dose with reduced systemic toxicities. We used primary GBM cells from both the tumour core and Brain Around the Tumour tissue from recurrent GBM patients to demonstrate that irinotecan is more effective than temozolomide. Irinotecan had a 75% response rate, while only 50% responded to temozolomide. With temozolomide the cell viability was never below 80% whereas irinotecan achieved cell viabilities of less than 44%. The iDES were manufactured using a hot melt extrusion process with accurate irinotecan drug loadings and the same cytotoxicity as unformulated irinotecan. The iDES released irinotecan in a sustained fashion for up to 7 days. However, only the 30, 40 and 50% w/w loaded iDES formulations released the 300 to 1000 μg of irinotecan needed to be effective in vivo. The 30 and 40% w/w iDES formulations containing 10% plasticizer and either 60 or 50% PLGA prolonged survival from 27 to 70 days in a GBM xenograft mouse resection model with no sign of tumour recurrence. The 30% w/w iDES formulations showed equivalent toxicity to a placebo in non-tumour bearing mice. This innovative drug delivery approach could transform the treatment of recurrent GBM patients by improving survival and reducing toxicity.

Comparison of Cell and Organoid-Level Analysis of Patient-Derived 3D Organoids to Evaluate Tumor Cell Growth Dynamics and Drug Response

3D cell culture models have been developed to better mimic the physiological environments that exist in human diseases. As such, these models are advantageous over traditional 2D cultures for screening drug compounds. However, the practicalities of transitioning from 2D to 3D drug treatment studies pose challenges with respect to analysis methods. Patient-derived tumor organoids (PDTOs) possess unique features given their heterogeneity in size, shape, and growth patterns. A detailed assessment of the length scale at which PDTOs should be evaluated (i.e., individual cell or organoid-level analysis) has not been done to our knowledge. Therefore, using dynamic confocal live cell imaging and data analysis methods we examined tumor cell growth rates and drug response behaviors in colorectal cancer (CRC) PDTOs. High-resolution imaging of H2B-GFP-labeled organoids with DRAQ7 vital dye permitted tracking of cellular changes, such as cell birth and death events, in individual organoids. From these same images, we measured morphological features of the 3D objects, including volume, sphericity, and ellipticity. Sphericity and ellipticity were used to evaluate intra- and interpatient tumor organoid heterogeneity. We found a strong correlation between organoid live cell number and volume. Linear growth rate calculations based on volume or live cell counts were used to determine differential responses to therapeutic interventions. We showed that this approach can detect different types of drug effects (cytotoxic vs cytostatic) in PDTO cultures. Overall, our imaging-based quantification workflow results in multiple parameters that can provide patient- and drug-specific information for screening applications.

Xanthohumol, a Prenylated Flavonoid from Hops, Induces DNA Damages in Colorectal Cancer Cells and Sensitizes SW480 Cells to the SN38 Chemotherapeutic Agent

In spite of chemotherapy and systematic screening for people at risk, the mortality rate of colorectal cancer (CRC) remains consistently high, with 600,000 deaths per year. This low success rate in the treatment of CRC results from many failures associated with high resistance and the risk of metastasis. Therefore, in response to these therapeutic failures, new strategies have been under development for several years aimed at increasing the effect of anticancer compounds and/or at reducing their secondary effects on normal cells, thus enabling the host to better withstand chemotherapy. This study highlights that xanthohumol (Xn) concentrations under the IC50 values were able to induce apoptosis and to enhance the DNA-damage response (DDR). We demonstrate for the first time that Xn exerts its anticancer activity in models of colon cancer through activation of the ataxia telangiectasia mutated (ATM) pathway. Subsequently, the ability of Xn to restore DNA damage in CRC cells can sensitize them to anticancer agents such as SN38 (7-ethyl-10-hydroxycamptothecin) used in chemotherapy.

The Personalisation of Glioblastoma Treatment Using Whole Exome Sequencing: A Pilot Study

The molecular heterogeneity of glioblastoma has been linked to differences in survival and treatment response, while the development of personalised treatments may be a novel way of combatting this disease. Here we show for the first time that low passage number cells derived from primary tumours are greater than an 86% match genetically to the tumour tissue. We used these cells to identify eight genes that could be used for the personalisation of glioblastoma treatment and discovered a number of personalised drug combinations that were significantly more effective at killing glioblastoma cells and reducing recurrence than the individual drugs as well as the control and non-personalised combinations. This pilot study demonstrates for the first time that whole exome sequencing has the potential be used to improve the treatment of glioblastoma patients by personalising treatment. This novel approach could potentially offer a new avenue for treatment for this terrible disease.

Synergistic action of doxorubicin and 7-Ethyl-10-hydroxycamptothecin polyphosphorylcholine polymer prodrug

There are opportunities for improvements to the efficiency and toxicity of widely used cancer chemotherapy agents such as doxorubicin (DOX·HCl) and 7-Ethyl-10-hydroxycamptothecin (SN38). We developed a safe and effective combination therapy by encapsulating DOX into micelles of a zwitterionic polymer prodrug, SN38 conjugate of poly (α-azide caprolactone-co-caprolactone)-b-poly (2-methacryloyloxyethyl phosphorylcholine [P(CL/CL-g-SN38)-b-PMPC)] which was described in our previous work. The polymer prodrug micelles displayed a higher loading capacity of DOX due to the π-π stacking effect between DOX and SN38 in comparison with the micelles self-assembled by prodrug's precursor, poly(α-azide caprolactone-co-caprolactone)-b-poly(2-methacryloyloxyethyl phosphorylcholine (P(ACL/CL)-b-PMPC). The DOX loaded prodrug micelles decelerated the release of DOX, and also prolonged its circulation. The micelles showed favorable cellular internalization by 4T1 cells. DOX loaded SN38 prodrug micelles displayed good in vitro anticancer effects owing to the synergistic action of doxorubicin and SN38 and were as effective as DOX·HCl, but with lower toxicity than DOX·HCl. Given the synergetic effects of free drug and polymer prodrug, this nanomedicine may offer a safe and effective drug delivery methodology for conventional drug formations.