Cellular and clinical pharmacology of the taxanes docetaxel and paclitaxel--a review. Anticancer Drugs. 2014;25:488-494. [PMID: 24637579 DOI: 10.1097/cad.0000000000000093]

Establishment and characterization of a sigmoid colon cancer organoid with spinal metastasis

Background

Sigmoid colon cancer with spinal metastases is rare in distant metastasis. In addition, the prognosis of colon cancer patients with spinal metastases is extremely poor. In order to find effective therapeutic agents, we need to know the biological characteristics of such patients from related models.

Methods

We collected sigmoid colon cancer tissue from a young female subject who was diagnosed with sigmoid colon cancer with multiple spinal metastases. We successfully established a sigmoid colon cancer organoid using this tissue and investigated drug screening in the patient. HE staining, immunohistochemistry, and DNA sequencing were utilized to compare the biological characteristics between the original tumor and the organoid. Furthermore, we investigated the drug screening of the sigmoid colon cancer organoid in vitro.

Results

A colon cancer organoid from sigmoid colon cancer with spinal metastases was successfully established. The organoid culture maintained the morphological features, histological features, and genomic landscape of the corresponding sigmoid colon cancer cells. Moreover, we performed drug screening tests to evaluate the effects of chemotherapeutic drugs and targeted drugs.

Conclusion

The sigmoid colon cancer organoid with spinal metastases was a favorable preclinical model to explore the clinicopathologic characteristics of colon cancer patients with spinal metastases.

Phase I Clinical Trial on Pleural Mesothelioma Using Neoadjuvant Local Administration of Paclitaxel-Loaded Mesenchymal Stromal Cells (PACLIMES Trial): Study Rationale and Design

Background and rationale. Pleural mesothelioma (PM) is a rare and aggressive neoplasm that originates from the pleural mesothelium and whose onset is mainly linked to exposure to asbestos, which cannot be attacked with truly effective therapies with consequent poor prognosis. The rationale of this study is based on the use of mesenchymal stromal cells (MSCs) as a vehicle for chemotherapy drugs to be injected directly into the pathological site, such as the pleural cavity. Study design. The study involves the use of a conventional chemotherapeutic drug, Paclitaxel (PTX), which is widely used in the treatment of different types of solid tumors, including PM, although some limitations are related to pharmacokinetic aspects. The use of PTX-loaded MSCs to treat PM should provide several potential advantages over the systemically administered drug as reduced toxicity and increased concentration of active drug in the tumor-surrounding context. The PACLIMES trial explores the safety and toxicity of the local administration of Paclimes in chemonaive patients, candidates for pleurectomy. The secondary objective is to find the effective Paclimes dose for subsequent phase II studies and to observe and record the antitumor activity. Future direction. The experimental pre-clinical background and rationale are discussed as well.

Is Higher Docetaxel Clearance in Prostate Cancer Patients Explained by Higher CYP3A? An In Vivo Phenotyping Study with Midazolam

Patients with prostate cancer (PCa) have a lower docetaxel exposure for both intravenous (1.8-fold) and oral administration (2.4-fold) than patients with other solid cancers, which could influence efficacy and toxicity. An altered metabolism by cytochrome P450 3A (CYP3A) due to castration status might explain the observed difference in docetaxel pharmacokinetics. In this in vivo phenotyping, pharmacokinetic study, CYP3A activity defined by midazolam clearance (CL) was compared between patients with PCa and male patients with other solid tumors. All patients with solid tumors who did not use CYP3A-modulating drugs were eligible for participation. Patients received 2 mg midazolam orally and 1 mg midazolam intravenously on 2 consecutive days. Plasma concentrations were measured with a validated liquid chromatography-tandem mass spectrometry method. Genotyping was performed for CYP3A4 and CYP3A5. Nine patients were included in each group. Oral midazolam CL was 1.26-fold higher in patients with PCa compared to patients with other solid tumors (geometric mean [coefficient of variation], 94.1 [33.5%] L/h vs 74.4 [39.1%] L/h, respectively; P = .08). Intravenous midazolam CL did not significantly differ between the 2 groups (P = .93). Moreover, the metabolic ratio of midazolam to 1'-hydroxy midazolam did not differ between the 2 groups for both oral administration (P = .67) and intravenous administration (P = .26). CYP3A4 and CYP3A5 genotypes did not influence midazolam pharmacokinetics. The observed difference in docetaxel pharmacokinetics between both patient groups therefore appears to be explained neither by a difference in midazolam CL nor by a difference in metabolic conversion rate of midazolam.

Osteoclast Cancer Cell Metabolic Cross-talk Confers PARP Inhibitor Resistance in Bone Metastatic Breast Cancer

The majority of patients with late-stage breast cancer develop distal bone metastases. The bone microenvironment can affect response to therapy, and uncovering the underlying mechanisms could help identify improved strategies for treating bone metastatic breast cancer. Here, we observed that osteoclasts reduced the sensitivity of breast cancer cells to DNA damaging agents, including cisplatin and the PARP inhibitor (PARPi) olaparib. Metabolic profiling identified elevated glutamine production by osteoclasts. Glutamine supplementation enhanced the survival of breast cancer cells treated with DNA damaging agents, while blocking glutamine uptake increased sensitivity and suppressed bone metastasis. GPX4, the critical enzyme responsible for glutathione oxidation, was upregulated in cancer cells following PARPi treatment through stress-induced ATF4-dependent transcriptional programming. Increased glutamine uptake and GPX4 upregulation concertedly enhanced glutathione metabolism in cancer cells to help neutralize oxidative stress and generate PARPi resistance. Analysis of paired patient samples of primary breast tumors and bone metastases revealed significant induction of GPX4 in bone metastases. Combination therapy utilizing PARPi and zoledronate, which blocks osteoclast activity and thereby reduces the microenvironmental glutamine supply, generated a synergistic effect in reducing bone metastasis. These results identify a role for glutamine production by bone-resident cells in supporting metastatic cancer cells to overcome oxidative stress and develop resistance to DNA-damaging therapies.

SIGNIFICANCE

Metabolic interaction between osteoclasts and tumor cells contributes to resistance to DNA-damaging agents, which can be blocked by combination treatment with PARP and osteoclast inhibitors to reduce bone metastatic burden.

Base-Promoted Glycosylation Allows Protecting Group-Free and Stereoselective O-Glycosylation of Carboxylic Acids

Here we report a simple and general method to achieve fully unprotected, stereoselective glycosylation of carboxylic acids, employing bench-stable allyl glycosyl sulfones as donors. Running the glycosylation reaction under basic conditions was crucial for the efficiencies and selectivities. Both the donor activation stage and the glycosidic bond forming stage of the process are compatible with free hydroxyl groups, thereby allowing for the use of fully unprotected glycosyl donors. This transformation is stereoconvergent, occurs under mild and metal-free conditions at ambient temperature with visible light (455 nm) irradiation, and displays remarkable scope with respect to both reaction partners. Many natural products and commercial drugs, including an acid derived from the complex anticancer agent taxol, were efficiently glycosylated. Experimental studies provide insights into the origin of the stereochemical outcome.

Photodynamic therapy induced cell cycle arrest and cancer cell synchronization: review

Cell cycle arrest (CCA) is seen as a prime candidate for effective cancer therapy. This mechanism can help researchers to create new treatments to target cancer cells at particular stages of the cell cycle (CC). The CCA is a characteristic of various therapeutic modalities, including radiation (RT) and chemotherapy (CT), which synchronizes the cells and facilitates the standardization of radio-chemotherapy protocols. Although it was discovered that photodynamic treatment (PDT) had a biological effect on CCA in cancer cells, the mechanism remains unclear. Furthermore, besides conventional forms of cell death such as apoptosis, autophagy, and necrosis, various unconventional types of cell death including pyroptosis, mitotic catastrophe, paraptosis, ferroptosis, necroptosis, and parthanatos after PDT have been reported. Thus, a variety of elements, such as oxygen, the tumor's microenvironment, the characteristics of light, and photosensitizer (PS), influence the effectiveness of the PDT treatment, which have not yet been studied clearly. This review focuses on CCA induced by PDT for a variety of PSs agents on various cell lines. The CCA by PDT can be viewed as a remarkable effect and instructive for the management of the PDT protocol. Regarding the relationship between the quantity of reactive oxygen species (ROS) and its biological consequences, we have proposed two mathematical models in PDT. Finally, we have gathered recent in vitro and in vivo studies about CCA post-PDT at various stages and made suggestions about how it can standardize, potentiate, and customize the PDT methodology.

The inhibitory and inducing effects of ritonavir on hepatic and intestinal CYP3A and other drug-handling proteins

Ritonavir, originally developed as HIV protease inhibitor, is widely used as a booster in several HIV pharmacotherapy regimens and more recently in Covid-19 treatment (e.g., Paxlovid). Its boosting capacity is due to the highly potent irreversible inhibition of the cytochrome P450 (CYP) 3 A enzyme, thereby enhancing the plasma exposure to coadministered drugs metabolized by CYP3A. Typically used booster doses of ritonavir are 100-200 mg once or twice daily. This review aims to address several aspects of this booster drug, including the possibility to use lower ritonavir doses, 20 mg for instance, resulting in partial CYP3A inactivation in patients. If complete CYP3A inhibition is not needed, lower ritonavir doses could be used, thereby reducing unwanted side effects. In this context, there are contradictory reports on the actual recovery time of CYP3A activity after ritonavir discontinuation, but probably this will take at least one day. In addition to ritonavir's CYP3A inhibitory effect, it can also induce and/or inhibit other CYP enzymes and drug transporters, albeit to a lesser extent. Although ritonavir thus exhibits gene induction capacities, with respect to CYP3A activity the inhibition capacity clearly predominates. Another potent CYP3A inhibitor, the ritonavir analog cobicistat, has been reported to lack the ability to induce enzyme and transporter genes. This might result in a more favorable drug-drug interaction profile compared to ritonavir, although the actual benefit appears to be limited. Indeed, ritonavir is still the clinically most used pharmacokinetic enhancer, indicating that its side effects are well manageable, even in chronic administration regimens.

PROTAC'ing oncoproteins: targeted protein degradation for cancer therapy

Molecularly targeted cancer therapies substantially improve patient outcomes, although the durability of their effectiveness can be limited. Resistance to these therapies is often related to adaptive changes in the target oncoprotein which reduce binding affinity. The arsenal of targeted cancer therapies, moreover, lacks coverage of several notorious oncoproteins with challenging features for inhibitor development. Degraders are a relatively new therapeutic modality which deplete the target protein by hijacking the cellular protein destruction machinery. Degraders offer several advantages for cancer therapy including resiliency to acquired mutations in the target protein, enhanced selectivity, lower dosing requirements, and the potential to abrogate oncogenic transcription factors and scaffolding proteins. Herein, we review the development of proteolysis targeting chimeras (PROTACs) for selected cancer therapy targets and their reported biological activities. The medicinal chemistry of PROTAC design has been a challenging area of active research, but the recent advances in the field will usher in an era of rational degrader design.

Nanoparticles loaded with pharmacologically active plant-derived natural products: Biomedical applications and toxicity

Pharmacologically active natural products have played a significant role in the history of drug development. They have acted as sources of therapeutic drugs for various diseases such as cancer and infectious diseases. However, most natural products suffer from poor water solubility and low bioavailability, limiting their clinical applications. The rapid development of nanotechnology has opened up new directions for applying natural products and numerous studies have explored the biomedical applications of nanomaterials loaded with natural products. This review covers the recent research on applying plant-derived natural products (PDNPs) nanomaterials, including nanomedicines loaded with flavonoids, non-flavonoid polyphenols, alkaloids, and quinones, especially their use in treating various diseases. Furthermore, some drugs derived from natural products can be toxic to the body, so the toxicity of them is discussed. This comprehensive review includes fundamental discoveries and exploratory advances in natural product-loaded nanomaterials that may be helpful for future clinical development.

Drugs That Changed Society: Microtubule-Targeting Agents Belonging to Taxanoids, Macrolides and Non-Ribosomal Peptides

During a screening performed by the National Cancer Institute in the 1960s, the terpenoid paclitaxel was discovered. Paclitaxel expanded the treatment options for breast, lung, prostate and ovarian cancer. Paclitaxel is only present in minute amounts in the bark of Taxia brevifolia. A sustainable supply was ensured with a culture developed from Taxus chinensis, or with semi-synthesis from other taxanes. Paclitaxel is marketed under the name Taxol. An intermediate from the semi-synthesis docetaxel is also used as a drug and marketed as Taxotere. O-Methylated docetaxel is used for treatment of some paclitaxel-resistant cancer forms as cabazitaxel. The solubility problems of paclitaxel have been overcome by formulation of a nanoparticle albumin-bound paclitaxel (NAB-paclitaxel, Abraxane). The mechanism of action is affinity towards microtubules, which prevents proliferation and consequently the drug would be expected primarily to be active towards cancer cells proliferating faster than benign cells. The activity against slowly growing tumors such as solid tumors suggests that other effects such as oncogenic signaling or cellular trafficking are involved. In addition to terpenoids, recently discovered microtubule-targeting polyketide macrolides and non-ribosomal peptides have been discovered and marketed as drugs. The revolutionary improvements for treatment of cancer diseases targeting microtubules have led to an intensive search for other compounds with the same target. Several polyketide macrolides, terpenoids and non-ribosomal peptides have been investigated and a few marketed.

Cellular and molecular insights into the roles of visfatin in breast cancer cells plasticity programs

Obesity has reached a pandemic proportion and is responsible for the augmentation of multimorbidity including certain cancers. With the rise in obesity amongst the female population globally, a concomitant increase in breast cancer (BC) incidence and related mortality has been observed. In the present review, we have elucidated the cellular and molecular insight into the visfatin-mediated cellular plasticity programs such as Epithelial to mesenchymal transition (EMT) and Endothelial to mesenchymal transition (EndoMT), and stemness-associated changes in BC cells. EMT and EndoMT are responsible for inducing metastasis in cancer cells and conferring chemotherapy resistance, immune escape, and infinite growth potential. Visfatin, an obesity-associated adipokine implicated in metabolic syndrome, has emerged as a central player in BC pathogenesis. Several studies have indicated the presence of visfatin in the tumor microenvironment (TME) where it augments EMT and EndoMT of BC cells. Further, Visfatin also modulates the TME by acting on the tumor stroma cells such as adipocytes, infiltrated immune cells, and adipose-associated stem cells that secrete factors such as cytokines, and extracellular vesicles responsible for augmenting cellular plasticity program. Visfatin induced altered metabolism of the cancer cells and molecular determinants such as non-coding RNAs involved in EMT and EndoMT have been discussed. We have also highlighted specific therapeutic targets that can be exploited for the development of effective BC treatment. Taken together, these advanced understandings of cellular and molecular insight into the visfatin-mediated cellular plasticity programs may stimulate the development of better approaches for the prevention and therapy of BC, especially in obese patients.

Nanoparticles Loaded with Docetaxel and Resveratrol as an Advanced Tool for Cancer Therapy

A growing interest in the use of a combination of chemosensitizers and cytostatics for overcoming cancer resistance to treatment and the development of their delivery systems has been observed. Resveratrol (Res) presents antioxidant, anti-inflammatory and chemopreventive properties but also limits multidrug resistance against docetaxel (Dtx), which is one of the main causes of failure in cancer therapy with this drug. However, the use of both drugs presents challenges, including poor bioavailability, the unfavourable pharmacokinetics and chemical instability of Res and the poor water solubility and dose-limiting toxicity of Dtx. In order to overcome these difficulties, attempts have been made to create different forms of delivery for both agents. This review is focused on the latest developments in nanoparticles for the delivery of Dtx, Res and for the combined delivery of those two drugs. The aim of this review was also to summarize the synergistic mechanism of action of Dtx and Res on cancer cells. According to recent reports, Dtx and Res loaded in a nano-delivery system exhibit better efficiency in cancer treatment compared to free drugs. Also, the co-delivery of Dtx and Res in one actively targeted delivery system providing the simultaneous release of both drugs in cancer cells has a chance to fulfil the requirements of effective anticancer therapy and reduce limitations in therapy caused by multidrug resistance (MDR).

Selective delivery of clinically approved tubulin binding agents through covalent conjugation to an active targeting moiety

Abstract:

The efficacy and tolerability of tubulin binding agents are hampered by their low specificity for cancer cells, like most clinically used anticancer agents. To improve specificity, tubulin binding agents have been covalently conjugated to agents which target cancer cells to give actively targeted drug conjugates. These conjugates are designed to increase uptake of the drug by cancer cells, while having limited uptake by normal cells thereby improving efficacy and tolerability. Approaches used include attachment to small molecules, polysaccharides, peptides, proteins and antibodies that exploit the overexpression of receptors for these substances. Antibody targeted strategies have been the most successful to date with six such examples having gained clinical approval. Many other conjugate types, especially those targeting the folate receptor, have shown promising efficacy and toxicity profiles in pre-clinical models and in early-stage clinical studies. Presented herein is a discussion of the success or otherwise of the recent strategies used to form these actively targeted conjugates.

Current status of therapeutic drug monitoring for methotrexate, imatinib, paclitaxel in China

BACKGROUND

Accurate TDMs of plasma methotrexate, imatinib and paclitaxel assist in the development of optimal therapeutic regimes. This study aims to investigate the current status of methotrexate, imatinib and paclitaxel measurements in China and explore the suitable EQA materials for those drugs.

METHODS

4 processed plasma samples including 2 levels of frozen pooled plasma samples and 2 levels of lyophilized pooled plasma samples were measured in different laboratories using different measurement systems. The inter-laboratory %CV and intra-measurement-system %CV of laboratories were calculated to assess the status of methotrexate, imatinib and paclitaxel measurements. The short-term stability and homogeneity of those processed samples were studied and compared. The relative differences (%) between the results of those two kinds of processed samples were also calculated to determine whether there were significant differences in their matrix effects for various measurement systems.

RESULTS

The mean inter-laboratory %CVs ranged from 12.8% to 15.3%, 14.7% to 19.6% and 56.8% to 81.6% for methotrexate, imatinib and paclitaxel, respectively. The intra-measurement %CV of homogeneous commercial measurement systems was better than other measurement systems. The lyophilized samples were more stable than frozen samples and there were no obvious differences in their matrix effects for most measurement systems.

CONCLUSIONS

The agreement among the results of methotrexate, imatinib, and especially paclitaxel from different laboratories was not satisfactory. Currently, the lyophilized samples were the more suitable EQA material for methotrexate, imatinib and paclitaxel than frozen samples.

Bismuth lipophilic nanoparticles (BisBAL NP) inhibit the growth of tumor cells in a mouse melanoma model

AIM

The objective of this study was to analyze the antitumor effect of BisBAL NP in a mouse melanoma model.

MATERIAL AND METHODS

The antitumor activity of BisBAL NP on murine B16-F10 melanoma cells was determined both in vitro (PrestoBlue cell viability assay and Live/Dead fluorescence) and in vivo, in a mouse model, with the following 15-day treatments: BisBAL NP, negative control (PBS), and cell-death control (docetaxel; DTX). Mouse survival and weight, as well as the tumor volume were recorded daily during the in vivo study.

RESULTS

BisBAL NP were homogeneous in size (mean diameter, 14.7 nm) and bismuth content. In vitro, 0.1 mg/mL BisBAL NP inhibited B16-F10 cell growth stronger (88%) than 0.1 mg/mL DTX (82%) (p<0.0001). In vivo, tumors in mice treated with BisBAL NP (50 mg/kg/day) or DTX (10 mg/kg/day) were 76% and 85% smaller than the tumors of negative control mice (p<0.0001). The average weight of mice was 18.1 g and no statistically significant difference was detected among groups during the study. Alopecia was only observed in all DTX-treated mice. The survival rate was 100% for the control and BisBAL NP groups, but one DTX- treated mouse died at the end of the treatment period. The histopathological analysis revealed that exposure to BisBAL NP was cytotoxic for tumor tissue only, without affecting the liver or kidney.

CONCLUSION

BisBAL NP decreased the tumor growing in a mouse melanoma model without secondary effects, constituting an innovative low-cost alternative to treat melanoma.

Albumin-Bound Paclitaxel: Worthy of Further Study in Sarcomas

Taxanes (paclitaxel and docetaxel) play an important role in the treatment of advanced sarcomas. Albumin-bound paclitaxel (nab-paclitaxel) is a new kind of taxane and has many advantages compared with paclitaxel and docetaxel. Nab-paclitaxel is currently approved for the treatment of advanced breast, non-small cell lung, and pancreatic cancers. However, the efficacy of nab-paclitaxel in sarcomas has not been reviewed. In this review, we first compare the similarities and differences among nab-paclitaxel, paclitaxel, and docetaxel and then summarize the efficacy of nab-paclitaxel against various non-sarcoma malignancies based on clinical trials with reported results. The efficacy and clinical research progress on nab-paclitaxel in sarcomas are also summarized. This review will serve as a good reference for the application of nab-paclitaxel in clinical sarcoma treatment studies and the design of clinical trials.

Controlled release nanoplatforms for three commonly used chemotherapeutics

In order to combat an evolving, multidimensional disease such as cancer, research has been aimed at synthesizing more efficient and effective versions of popular chemotherapeutic drugs. Despite these efforts, there remains a necessity for the development of suitable delivery vehicles that can both harness the chemotherapeutic effects meanwhile reducing some of the known issues when using these drugs such as unwanted side-effects, acquired drug resistance, and associated difficulties with drug delivery. Synthetic drug discovery approaches focusing on modification of the native structure of these chemotherapeutic drugs often face challenges such as loss of efficacy, as well as a potential worsening of side-effects. Synthetic chemists are then left with increasingly narrow choices for possible chemistry they could implement to achieve the desired therapy. The emergence of targeted therapies using controlled-release nanomaterials can provide many opportunities for conventional chemotherapeutic drugs to be delivered to specific target sites, ultimately leading to reduced side-effects and improved efficacy. Logically, it may prove advantageous to consider nano-delivery systems as a likely candidate for circumventing some of the barriers associated with creating viable drug therapies. In this review, we summarize controlled release nanoformulations of the three most widely used and approved chemotherapeutics, doxorubicin, paclitaxel, and cisplatin as an alternative therapeutic approach against different cancer types.

Paclitaxel-Induced Epidermal Alterations: An In Vitro Preclinical Assessment in Primary Keratinocytes and in a 3D Epidermis Model

Paclitaxel is a microtubule-stabilizing chemotherapeutic agent approved for the treatment of ovarian, non-small cell lung, head, neck, and breast cancers. Despite its beneficial effects on cancer and widespread use, paclitaxel also damages healthy tissues, including the skin. However, the mechanisms that drive these skin adverse events are not clearly understood. In the present study, we demonstrated, by using both primary epidermal keratinocytes (NHEK) and a 3D epidermis model, that paclitaxel impairs different cellular processes: paclitaxel increased the release of IL-1α, IL-6, and IL-8 inflammatory cytokines, produced reactive oxygen species (ROS) release and apoptosis, and reduced the endothelial tube formation in the dermal microvascular endothelial cells (HDMEC). Some of the mechanisms driving these adverse skin events in vitro are mediated by the activation of toll-like receptor 4 (TLR-4), which phosphorylate transcription of nuclear factor kappa B (NF-κb). This is the first study analyzing paclitaxel effects on healthy human epidermal cells with an epidermis 3D model, and will help in understanding paclitaxel's effects on the skin.

Multi-CpG linear regression models to accurately predict paclitaxel and docetaxel activity in cancer cell lines

The microtubule-targeting paclitaxel (PTX) and docetaxel (DTX) are widely used chemotherapeutic agents. However, the dysregulation of apoptotic processes, microtubule-binding proteins, and multi-drug resistance efflux and influx proteins can alter the efficacy of taxane drugs. In this review, we have created multi-CpG linear regression models to predict the activities of PTX and DTX drugs through the integration of publicly available pharmacological and genome-wide molecular profiling datasets generated using hundreds of cancer cell lines of diverse tissue of origin. Our findings indicate that linear regression models based on CpG methylation levels can predict PTX and DTX activities (log-fold change in viability relative to DMSO) with high precision. For example, a 287-CpG model predicts PTX activity at R² of 0.985 among 399 cell lines. Just as precise (R²=0.996) is a 342-CpG model for predicting DTX activity in 390 cell lines. However, our predictive models, which employ a combination of mRNA expression and mutation as input variables, are less accurate compared to the CpG-based models. While a 290 mRNA/mutation model was able to predict PTX activity with R² of 0.830 (for 546 cell lines), a 236 mRNA/mutation model could calculate DTX activity at R² of 0.751 (for 531 cell lines). The CpG-based models restricted to lung cancer cell lines were also highly predictive (R²≥0.980) for PTX (74 CpGs, 88 cell lines) and DTX (58 CpGs, 83 cell lines). The underlying molecular biology behind taxane activity/resistance is evident in these models. Indeed, many of the genes represented in PTX or DTX CpG-based models have functionalities related to apoptosis (e.g., ACIN1, TP73, TNFRSF10B, DNASE1, DFFB, CREB1, BNIP3), and mitosis/microtubules (e.g., MAD1L1, ANAPC2, EML4, PARP3, CCT6A, JAKMIP1). Also represented are genes involved in epigenetic regulation (HDAC4, DNMT3B, and histone demethylases KDM4B, KDM4C, KDM2B, and KDM7A), and those that have never been previously linked to taxane activity (DIP2C, PTPRN2, TTC23, SHANK2). In summary, it is possible to accurately predict taxane activity in cell lines based entirely on methylation at multiple CpG sites.

Docetaxel-triggered SIDT2/NOX4/JNK/HuR signaling axis is associated with TNF-α-mediated apoptosis of cancer cells

Previous studies have confirmed that docetaxel (DTX) treatment increases TNF-α production in cancer cells, but its mechanism of action remains unclear. Therefore, this study aimed to determine the signaling axis by which DTX induced the expression of TNF-α in U937 leukemia and MCF-7 breast carcinoma cells. DTX treatment promoted Ca²⁺-controlled autophagy and SIDT2 expression, resulting in lysosomal degradation of miR-25 in U937 cells. Downregulation of miR-25 increased NOX4 mRNA stability and protein expression. NOX4-stimulated ROS generation led to JNK-mediated phosphorylation of cytosolic HuR at Ser221, thereby increasing TNF-α protein expression by stabilizing TNF-α mRNA. Consequently, DTX induced TNF-α-dependent death in U937 cells. Depletion of HuR using siRNA or abolishment of JNK activation reduced TNF-α expression and eliminated DTX-mediated cytotoxicity. Knockdown of SIDT2 or pretreatment with chloroquine (a lysosome inhibitor) reduced DTX-induced NOX4 and TNF-α expression and mitigated JNK-mediated HuR phosphorylation. Altogether, our data indicate that DTX triggers HuR-mediated TNF-α mRNA stabilization through the Ca²⁺/SIDT2/NOX4/ROS/JNK axis, thereby inducing TNF-α-dependent apoptosis in U937 cells. In addition, DTX induces apoptosis in MCF-7 cells through SIDT2/NOX4/JNK/HuR axis-mediated TNF-α expression.

Antineoplastics Encapsulated in Nanostructured Lipid Carriers

Ideally, antineoplastic treatment aims to selectively eradicate cancer cells without causing systemic toxicity. A great number of antineoplastic agents (AAs) are available nowadays, with well-defined therapeutic protocols. The poor bioavailability, non-selective action, high systemic toxicity, and lack of effectiveness of most AAs have stimulated the search for novel chemotherapy protocols, including technological approaches that provide drug delivery systems (DDS) for gold standard medicines. Nanostructured lipid carriers (NLC) are DDS that contain a core of solid and lipid liquids stabilised by surfactants. NLC have high upload capacity for lipophilic drugs, such as the majority of AAs. These nanoparticles can be prepared with a diversity of biocompatible (synthetic or natural) lipid blends, administered by different routes and functionalised for targeting purposes. This review focused on the research carried out from 2000 to now, regarding NLC formulations for AAs (antimetabolites, antimitotics, alkylating agents, and antibiotics) encapsulation, with special emphasis on studies carried out in vivo. NLC systems for codelivery of AAs were also considered, as well as those for non-classical drugs and therapies (natural products and photosensitisers). NLC have emerged as powerful DDS to improve the bioavailability, targeting and efficacy of antineoplastics, while decreasing their toxic effect in the treatment of different types of cancer.

Personalized medicine of non-gene-specific chemotherapies for non-small cell lung cancer

Non-small cell lung cancer is recognized as the deadliest cancer across the globe. In some areas, it is more common in women than even breast and cervical cancer. Its rise, vaulted by smoking habits and increasing air pollution, has garnered much attention and resource in the medical field. The first lung cancer treatments were developed more than half a century ago. Unfortunately, many of the earlier chemotherapies often did more harm than good, especially when they were used to treat genetically unsuitable patients. With the introduction of personalized medicine, physicians are increasingly aware of when, how, and in whom, to use certain anti-cancer agents. Drugs such as tyrosine kinase inhibitors, anaplastic lymphoma kinase inhibitors, and monoclonal antibodies possess limited utility because they target specific oncogenic mutations, but other drugs that target mechanisms universal to all cancers do not. In this review, we discuss many of these non-oncogene-targeting anti-cancer agents including DNA replication inhibitors (i.e., alkylating agents and topoisomerase inhibitors) and cytoskeletal function inhibitors to highlight their application in the setting of personalized medicine as well as their limitations and resistance factors.

A Review on Drug Delivery System for Tumor Therapy

In recent years, with the development of nanomaterials, the research of drug delivery systems has become a new field of cancer therapy. Compared with conventional antitumor drugs, drug delivery systems such as drug nanoparticles (NPs) are expected to have more advantages in antineoplastic effects, including easy preparation, high efficiency, low toxicity, especially active tumor-targeting ability. Drug delivery systems are usually composed of delivery carriers, antitumor drugs, and even target molecules. At present, there are few comprehensive reports on a summary of drug delivery systems applied for tumor therapy. This review introduces the preparation, characteristics, and applications of several common delivery carriers and expounds the antitumor mechanism of different antitumor drugs in delivery carriers in detail which provides a more theoretical basis for clinical application of personalized cancer nanomedicine in the future.

Single nucleotide polymorphisms to predict taxanes toxicities and effectiveness in cancer patients

Taxanes are used in the treatment of several solid tumours. Adverse events (AEs) might be influenced by single nucleotide polymorphisms (SNPs) in genes encoding proteins responsible for pharmacokinetic and pharmacodynamic. In this prospective, monocentric, observational study we explored the effect of SNPs in the main genes involved in taxanes metabolism and transport, on toxicity and efficacy in 125 patients (pts) treated with paclitaxel, nab-paclitaxel, or docetaxel for neoplasms. There was no statistically significant association between the investigated SNPs and AEs. The heterozygous genotype of CYP3A4*22 showed a trend of association with skin reactions in pts treated with paclitaxel and nab-paclitaxel (RR = 6.92; 95% CI 0.47, 99.8; p = 0.0766). CYP2C8*3/*4 variant carriers showed a trend of association with overall AEs in pts treated with paclitaxel and nab-paclitaxel (RR = 1.28; 95% CI 0.96, 1.67; p = 0.0898). No statistically significant relationship with treatment efficacy was found. ABCB1 3435TT showed a trend of association with a higher treatment response (RR = 0.22; 95% CI 0.03, 1.51; p = 0.0876). Despite the population was heterogeneous, CYP3A4*22 and CYP2C8 SNPs may influence paclitaxel and nab-paclitaxel toxicity and ABCB1 c.3435 may affect taxanes effectiveness, even if any statistically significant was found.

Imidazoles as Potential Anticancer Agents: An Update on Recent Studies

Nitrogen-containing heterocyclic rings are common structural components of marketed drugs. Among these heterocycles, imidazole/fused imidazole rings are present in a wide range of bioactive compounds. The unique properties of such structures, including high polarity and the ability to participate in hydrogen bonding and coordination chemistry, allow them to interact with a wide range of biomolecules, and imidazole-/fused imidazole-containing compounds are reported to have a broad spectrum of biological activities. This review summarizes recent reports of imidazole/fused imidazole derivatives as anticancer agents appearing in the peer-reviewed literature from 2018 through 2020. Such molecules have been shown to modulate various targets, including microtubules, tyrosine and serine-threonine kinases, histone deacetylases, p53-Murine Double Minute 2 (MDM2) protein, poly (ADP-ribose) polymerase (PARP), G-quadraplexes, and other targets. Imidazole-containing compounds that display anticancer activity by unknown/undefined mechanisms are also described, as well as key features of structure-activity relationships. This review is intended to provide an overview of recent advances in imidazole-based anticancer drug discovery and development, as well as inspire the design and synthesis of new anticancer molecules.

Geminal Diheteroatomic Motifs: Some Applications of Acetals, Ketals, and Their Sulfur and Nitrogen Homologues in Medicinal Chemistry and Drug Design

Acetals and ketals and their nitrogen and sulfur homologues are often considered to be unconventional and potentially problematic scaffolding elements or pharmacophores for the design of orally bioavailable drugs. This opinion is largely a function of the perception that such motifs might be chemically unstable under the acidic conditions of the stomach and upper gastrointestinal tract. However, even simple acetals and ketals, including acyclic molecules, can be sufficiently robust under acidic conditions to be fashioned into orally bioavailable drugs, and these structural elements are embedded in many effective therapeutic agents. The chemical stability of molecules incorporating geminal diheteroatomic motifs can be modulated by physicochemical design principles that include the judicious deployment of proximal electron-withdrawing substituents and conformational restriction. In this Perspective, we exemplify geminal diheteroatomic motifs that have been utilized in the discovery of orally bioavailable drugs or drug candidates against the backdrop of understanding their potential for chemical lability.

Current opinion on the pharmacogenomics of paclitaxel-induced toxicity

Introduction: Paclitaxel is a microtubule stabilizer that is currently one of the most utilized chemotherapeutic agents. Its efficacy in breast, uterine, lung and other neoplasms made its safety profile enhancement a subject of great interest. Neurotoxicity is the most common paclitaxel-associated toxicities. In addition, hypersensitivity reactions, hematological, gastrointestinal, and cardiac toxicities are all encountered.Areas covered: The current review explores paclitaxel-induced toxicities mechanisms and risk factors. Studies investigating these toxicities pharmacogenomic biomarkers are reviewed and summarized. There is a limited margin of consistency between the retrieved associations. Variants in genes related to neuro-sensitivity are the most promising candidates for future studies.Expert opinion: Genome-wide association studies highlighted multiple-candidate biomarkers relevant to neuro-sensitivity. Most of the identified paclitaxel-neurotoxicity candidate genes are derived from congenital neuropathy and diabetic-induced neurotoxicity pathways. Future studies should explore these sets of genes while considering the multifactorial nature of paclitaxel-induced neurotoxicity. In the absence of certain paclitaxel-toxicity biomarkers, future research should avoid earlier studies' caveats. Genes in paclitaxel's pharmacokinetic pathways could not provide consistent results in any of its associated toxicities. There is a need to dig deeper into toxicity-development mechanisms and personal vulnerability factors, rather than targeting only the genes suspected to affect drug exposure.

Breast cancer: Muscarinic receptors as new targets for tumor therapy

The development of breast cancer is a complex process that involves the participation of different factors. Several authors have demonstrated the overexpression of muscarinic acetylcholine receptors (mAChRs) in different tumor tissues and their role in the modulation of tumor biology, positioning them as therapeutic targets in cancer. The conventional treatment for breast cancer involves surgery, radiotherapy, and/or chemotherapy. The latter presents disadvantages such as limited specificity, the appearance of resistance to treatment and other side effects. To prevent these side effects, several schedules of drug administration, like metronomic therapy, have been developed. Metronomic therapy is a type of chemotherapy in which one or more drugs are administered at low concentrations repetitively. Recently, two chemotherapeutic agents usually used to treat breast cancer have been considered able to activate mAChRs. The combination of low concentrations of these chemotherapeutic agents with muscarinic agonists could be a useful option to be applied in breast cancer treatment, since this combination not only reduces tumor cell survival without affecting normal cells, but also decreases pathological neo-angiogenesis, the expression of drug extrusion proteins and the cancer stem cell fraction. In this review, we focus on the previous evidences that have positioned mAChRs as relevant therapeutic targets in breast cancer and analyze the effects of administering muscarinic agonists in combination with conventional chemotherapeutic agents in a metronomic schedule.

Establishment of the tandem mass spectrometric fingerprints of taxane-based anticancer compounds

RATIONALE

Compounds in the taxane drug family are among the most successful and effective chemotherapeutic agents used in the treatment of solid tumors, such as breast, ovarian, and prostate cancers. The tandem mass spectrometric (MS/MS) fragmentation behavior of these compounds is described in detail, and a generalized MS/MS fingerprint is established for the first time.

METHODS

Five compounds, namely paclitaxel, docetaxel, cabazitaxel, cephalomannine, and baccatin III, were evaluated. A hybrid quadrupole orthogonal time-of-flight (Q-TOF) mass spectrometer was used to obtain accurate mass measurements, whereas MS/MS and second-generation MS/MS (MS³ ) analyses were performed using a triple quadrupole-linear ion trap mass spectrometer. Both instruments were equipped with an electrospray ionization source operated in the positive ion mode.

RESULTS

All taxanes showed an abundant singly charged [M + H]⁺ species in the single-stage analysis with mass accuracies less than 3 ppm. The evaluated compounds exhibited common fragmentation behavior in their MS/MS analysis, which allowed for the production of a universal fragmentation pattern. MS³ experiments confirmed the genesis of the various product ions proposed in the fragmentation pathway. In addition, diagnostic product ions were originated from a cleavage in the ester bond between the core diterpene ring structure and the side chain.

CONCLUSIONS

Varying functional groups present in these compounds resulted in unique product ions that are specific to each structure. The established MS/MS fingerprints will be used in the near future for identification and for the development of multiple reaction monitoring liquid chromatography-MS/MS quantification methods.

Population Pharmacokinetics and Exposure-Safety Relationship of Paclitaxel Liposome in Patients With Non-small Cell Lung Cancer

Purpose

Paclitaxel liposome (Lipusu) is the first commercialized liposomal formulation of paclitaxel. There has been little data collected on the pharmacokinetics (PK) of paclitaxel liposome, especially in relation to patient use. This study aimed to build a population pharmacokinetic (PopPK) model and further explore the exposure–safety relationship for paclitaxel liposome in patients with non-small cell lung cancer (NSCLC).

Methods

Data from 45 patients with a total of 349 plasma concentrations were analyzed. The PopPK model was built using the non-linear mixed effect modeling technique.

Results

The PK of paclitaxel liposome were well described by a three-compartment model with first-order elimination. For a dose of 175 mg m^–2, the estimated clearance of total plasma paclitaxel was 21.55 L h^–1. Age, sex, body weight, total bilirubin, albumin, serum creatinine, and creatinine clearance did not influence the paclitaxel PK. Exposure to paclitaxel had no significant change in the presence of the traditional Chinese medicine, aidi injection. The exploratory exposure–safety relationship was well described by a generalized linear regression model. Higher probabilities of grade >1 neutropenia were observed in patients with higher exposure to paclitaxel.

Conclusion

This PopPK model adequately described the PK of paclitaxel liposome in patients with NSCLC. Predicted exposure of paclitaxel did not change in the presence of the traditional Chinese medicine, aidi injection. The exposure–safety analysis suggested that a higher risk of neutropenia was correlated with higher exposure to paclitaxel.

Click activated protodrugs against cancer increase the therapeutic potential of chemotherapy through local capture and activation

A desired goal of targeted cancer treatments is to achieve high tumor specificity with minimal side effects. Despite recent advances, this remains difficult to achieve in practice as most approaches rely on biomarkers or physiological differences between malignant and healthy tissue, and thus benefit only a subset of patients in need of treatment. To address this unmet need, we introduced a Click Activated Protodrugs Against Cancer (CAPAC) platform that enables targeted activation of drugs at a specific site in the body, i.e., a tumor. In contrast to antibodies (mAbs, ADCs) and other targeted approaches, the mechanism of action is based on in vivo click chemistry, and is thus independent of tumor biomarker expression or factors such as enzymatic activity, pH, or oxygen levels. The CAPAC platform consists of a tetrazine-modified sodium hyaluronate-based biopolymer injected at a tumor site, followed by one or more doses of a trans-cyclooctene (TCO)-modified cytotoxic protodrug with attenuated activity administered systemically. The protodrug is captured locally by the biopolymer through an inverse electron-demand Diels–Alder reaction between tetrazine and TCO, followed by conversion to the active drug directly at the tumor site, thereby overcoming the systemic limitations of conventional chemotherapy or the need for specific biomarkers of traditional targeted therapies. Here, TCO-modified protodrugs of four prominent cytotoxics (doxorubicin, paclitaxel, etoposide and gemcitabine) are used, highlighting the modularity of the CAPAC platform. In vitro evaluation of cytotoxicity, solubility, stability and activation rendered the protodrug of doxorubicin, SQP33, as the most promising candidate for in vivo studies. In mice, the maximum tolerated dose (MTD) of SQP33 in combination with locally injected tetrazine-modified biopolymer (SQL70) was determined to be 19.1-times the MTD of conventional doxorubicin. Pharmacokinetics studies in rats show that a single injection of SQL70 efficiently captures multiple SQP33 protodrug doses given cumulatively at 10.8-times the MTD of conventional doxorubicin with greatly reduced systemic toxicity. Finally, combined treatment with SQL70 and SQP33 (together called SQ3370) showed antitumor activity in a syngeneic tumor model in mice.

The Click Activated Protodrugs Against Cancer (CAPAC) platform uses click chemistry to activate cytotoxic drugs directly at a target site with minimal toxicity, overcoming limitations of conventional chemotherapy and traditional targeted therapies.

Small molecule drug conjugates (SMDCs): an emerging strategy for anticancer drug design and discovery

Mechanisms of how SMDCs work. Small molecule drugs are conjugated with the targeted ligand using pH sensitive linkers which allow the drug molecule to get released at lower lysosomal pH. It helps to accumulate the chemotherapeutic agents to be localized in the tumor environment upon cleaving of the pH-labile bonds.

Evaluation of the Physicochemical Properties, Pharmacokinetics, and In Vitro Anticancer Effects of Docetaxel and Osthol Encapsulated in Methoxy Poly(ethylene glycol)-b-Poly(caprolactone) Polymeric Micelles

Docetaxel (DTX), a taxane-based anticancer drug, and osthol (OTH), a coumarin-derivative compound, have shown anticancer effects against different types of cancers through various mechanisms. However, these drugs have low solubility in water and low oral bioavailability, and thus their clinical application is difficult. To overcome these problems, we encapsulated DTX and OTH in methoxy poly(ethylene glycol)-b-poly(caprolactone) (mPEG-b-PCL) and conducted studies in vitro and in vivo. We selected a 1:4 ratio as the optimal ratio of DTX and OTH, through combination index analysis in A549 cancer cells, and prepared micelles to evaluate the encapsulation efficiency, drug loading, particle size, and zeta potential. The in vitro drug-release profile showed that DTX/OTH-loaded mPEG-b-PCL micelles could slowly release DTX and OTH. In the clonogenic assay, DTX/OTH-loaded mPEG-b-PCL micelles showed 3.7 times higher inhibitory effect than the DTX/OTH solution. Pharmacokinetic studies demonstrated that micelles in combination with DTX and OTH exhibited increased area under curve and decreased clearance values, as compared with single micelles.

Fluorescence Anisotropy-Based Tethering for Discovery of Protein-Protein Interaction Stabilizers

Protein-protein interaction (PPI) networks are fundamental for cellular processes. Small-molecule PPI enhancers have been shown to be powerful tools to fundamentally study PPIs and as starting points for potential new therapeutics. Yet, systematic approaches for their discovery are not widely available, and the design prerequisites of "molecular glues" are poorly understood. Covalent fragment-based screening can identify chemical starting points for these enhancers at specific sites in PPI interfaces. We recently reported a mass spectrometry-based disulfide-trapping (tethering) approach for a cysteine residue in the hub protein 14-3-3, an important regulator of phosphorylated client proteins. Here, we invert the strategy and report the development of a functional read-out for systematic identification of PPI enhancers based on fluorescence anisotropy (FA-tethering) with the reactive handle now on a client-derived peptide. Using the DNA-binding domain of the nuclear receptor Estrogen Related Receptor gamma (ERRγ), we target a native cysteine positioned at the 14-3-3 PPI interface and identify several fragments that form a disulfide bond to ERRγ and stabilize the complex up to 5-fold. Crystallography indicates that fragments bind in a pocket comprised of 14-3-3 and the ERRγ phosphopeptide. FA-tethering presents a streamlined methodology to discover molecular glues for protein complexes.

Ganoderma triterpenoids attenuate tumour angiogenesis in lung cancer tumour-bearing nude mice

CONTEXT

Ganoderma lucidum (Leyss. ex Fr.) Karst. (Polyporaceae) triterpenoids (GLTs), the main components and bioactive metabolites of G. lucidum, have antitumour activity.

OBJECTIVE

We investigated the effects of GLTs in lung cancer tumour-bearing nude mice and their potential mechanism.

MATERIALS AND METHODS

Forty BALB/c nude mice were randomly divided into four groups: saline control, GLT (1 g/kg/day), gefitinib (GEF, 15 mg/kg/day), and GLT (1 g/kg/day) + GEF (15 mg/kg/day) for 14 days. Cell viability was conducted using the Cell Counting Kit-8 assay. The tumour volume, inhibition rate, histopathological, microvessel density (MVD), mRNAs, and proteins were determined.

RESULTS

GLTs inhibited the cell viability of A549 cells with an IC₅₀ value of 14.38 ± 0.29 mg/L, while the IC₅₀ value of GEF was 10.26 ± 0.47 μmol/L. The tumour inhibition rate in the GLT + GEF group (51.54%) was significantly decreased relative to the saline control… group (p < 0.05). The MVD in the GLT + GEF group (2.9 ± 0.7) was significantly decreased than that in the saline control group (12.8 ± 1.4, p < 0.05). The angiostatin, endostatin, and Bax protein expression in the GLT, GEF, and GLT + GEF groups were significantly increased compared to those in the saline control group, while the VEGFR2 and Bcl-2 protein expression were decreased.

DISCUSSION AND CONCLUSIONS

Our study provided evidence that GLT and GEF combination therapy may be a promising candidate for the treatment of lung cancer and as an experimental basis for clinical treatment.

Ophthalmic adverse effects of taxanes: The Mayo Clinic experience

PURPOSE

To investigate ophthalmic side effects of taxanes and compare side effect frequency, requirement for cessation of taxane therapy, visual acuity outcome, and concurrent systemic effects between paclitaxel and docetaxel.

METHODS

Patients taking taxanes at a single center from 1/1/2010 to 2/29/2020 were retrospectively reviewed for clinical characteristics, treatments, and concurrent systemic adverse effects.

RESULTS

Of 1918 patients, 22 (1.1%) experienced an ophthalmic side effect that came to the attention of an eye care provider. Mean age at presentation of the side effect was 62 years (median 66, range 23-82). The most common side effect was meibomian gland dysfunction in 5 (23%) patients, followed by cystoid macular edema in 4 (18%) patients and canalicular obstruction in 4 (18%) patients, followed by diplopia in 2 (9%) patients, and singular cases of lash alopecia, and blepharitis, among others. Lids/lashes as well as nasolacrimal duct adverse effects occurred more frequently with docetaxel therapy than with paclitaxel therapy. Follow-up was available in 10 (45%) patients, with mean duration of 5 months (median 4, range 0-12 months). Of these patients, the ophthalmic side effects were resolved or controlled without discontinuing therapy in 8 (80%) patients. Taxane cessation was required in one patient with docetaxel-related canalicular obstruction and one patient with paclitaxel-related cystoid macular edema.

CONCLUSION

Ophthalmic taxane-related adverse events are rare with estimated frequency of ophthalmic side effects of about 1%. Nevertheless, it is important that ophthalmologists recognize the range of side effects for optimal management. Most ophthalmic events can be treated with targeted therapy without discontinuation of life-prolonging taxane therapy.

Ototoxicity in patients with invasive ductal breast cancer who were treated with docetaxel: report of two cases

Docetaxel is an important anti-microtubule agent used to treat a variety of solid tumors, including breast cancer; notably, docetaxel-containing regimens improve outcomes for patients in metastatic, adjuvant, and neoadjuvant settings. However, the effectiveness of docetaxel in clinical practice can be compromised by suboptimal management of side effects. Here, we report two cases of docetaxel-based chemotherapy regimens in patients who exhibited invasive ductal breast cancer and underwent two different clinical treatment approaches. A 58-year-old postmenopausal female received salvage treatment with 8 cycles of docetaxel (67 mg/m²), and a 74-year-old female received 1 cycle of docetaxel (100 mg/m²). The two patients exhibited considerable hearing loss two days later. Of note, both patients had no hearing loss symptoms prior to docetaxel. Thus, ototoxicity may be a side effect of docetaxel that should be considered during treatment.

Impact of molecular weight on the mechanism of cellular uptake of polyethylene glycols (PEGs) with particular reference to P-glycoprotein

Polyethylene glycols (PEGs) in general use are polydisperse molecules with molecular weight (MW) distributed around an average value applied in their designation e.g., PEG 4000. Previous research has shown that PEGs can act as P-glycoprotein (P-gp) inhibitors with the potential to affect the absorption and efflux of concomitantly administered drugs. However, questions related to the mechanism of cellular uptake of PEGs and the exact role played by P-gp has not been addressed. In this study, we examined the mechanism of uptake of PEGs by MDCK-mock cells, in particular, the effect of MW and interaction with P-gp by MDCK-hMDR1 and A549 cells. The results show that: (a) the uptake of PEGs by MDCK-hMDR1 cells is enhanced by P-gp inhibitors; (b) PEGs stimulate P-gp ATPase activity but to a much lesser extent than verapamil; and (c) uptake of PEGs of low MW (<2000 Da) occurs by passive diffusion whereas uptake of PEGs of high MW (>5000 Da) occurs by a combination of passive diffusion and caveolae-mediated endocytosis. These findings suggest that PEGs can engage in P-gp-based drug interactions which we believe should be taken into account when using PEGs as excipients and in PEGylated drugs and drug delivery systems.

Efficacy of Metformin and Chemotherapeutic Agents on the Inhibition of Colony Formation and Shh/Gli1 Pathway: Metformin/Docetaxel Versus Metformin/5-Fluorouracil

BACKGROUND

Gastric cancer is a common gastrointestinal cancer characterized by poor prognosis and chemoresistance. Docetaxel and 5-fluorouracil (5-FU) are frequently used for the treatment of gastric cancer. Despite their potent anti-cancer effects, chemoresistance occurs in metastatic gastric cancer. Metformin, a popular anti-diabetic drug, has been proven to have potent anticancer effects on gastrointestinal cancers. Here, we aim to improve this chemotherapy agents' efficacy by pretreatment with metformin.

METHODS

The AGS gastric cancer cell line were pretreated with three different sub-toxic concentration of metformin and then treated with various concentrations of 5-FU and docetaxel.The anticancer effects of the combination of metformin with the chemotherapy agents were determined using clonogenic assay and DAPi staining. We used real-time PCR to evaluate Gli1, Gli2, and TWIST1 mRNA expression levels in the gastric cancer cells. Also, the expression of the Shh protein was assessed using immunocytochemistry.

RESULTS

Here, we found that metformin sensitized the gastric cancer cells to chemotherapy. The combination treatments were more effective in reducing the number of cancer colonies compared to 5-FU or docetaxel alone. The combination of metformin with 5-FU or docetaxel significantly reduced the number of cells expressing the Shh protein compared to the 5-FU alone or docetaxel alone. Interestingly, we found that the combination of metformin with docetaxel significantly down-regulated the mRNA levels of Gli1, Gli2, and TWIST1 in the AGS gastric cancer cell line compared to docetaxel alone.

CONCLUSION

Overall, our data strongly support an important role for metformin as an enhancer of the efficacy of chemotherapeutic agents against gastric cancer.

Development, Characterization and In Vitro Evaluation of Paclitaxel and Anastrozole Co-Loaded Liposome

Paclitaxel (PTX) and anastrozole (ANA) have been frequently applied in breast cancer treatment. PTX is well-known for its anti-proliferative effect meanwhile ANA has just been discovered to act as an estrogen receptor α (ERα) ligand. The combination therapy of PTX and ANA is expected to improve treating efficiency, as ANA would act as a ligand binding with the ERα gene expressed in breast cancer cells and thereafter PTX would inhibit the division and cause death to those cancer cells. In this study, liposome-based nanocarriers (LP) were developed for co-encapsulation of PTX and ANA to improve the efficacy of the combined drugs in an Estrogen receptor-responsive breast cancer study. PTX-ANA co-loaded LP was prepared using thin lipid film hydration method and was characterized for morphology, size, zeta potential, drug encapsulation and in vitro drug release. In addition, cell proliferation (WST assay) and IN Cell Analyzer were used for in vitro cytotoxicity studies on a human breast cancer cell line (MCF-7). Results showed that the prepared LP and PTX-ANA-LP had spherical vesicles, with a mean particle size of 170.1 ± 13.5 nm and 189.0 ± 22.1 nm, respectively. Controlled and sustained releases were achieved at 72 h for both of the loaded drugs. The in vitro cytotoxicity study found that the combined drugs showed higher toxicity than each single drug separately. These results suggested a new approach to breast cancer treatment, consisting of the combination therapy of PTX and ANA in liposomes based on ER response.

ABCB1 and ABCC2 genetic polymorphism as risk factors for neutropenia in esophageal cancer patients treated with docetaxel, cisplatin, and 5-fluorouracil chemotherapy

PURPOSE

The combination of docetaxel, cisplatin and 5-fluorouracil (DCF) is a newly developed chemotherapy regimen for esophageal cancer. Severe neutropenia is dose-limiting toxicity of docetaxel and it is well known to be frequently occurred during DCF chemotherapy. This study aimed to investigate the relationship between severe neutropenia and genetic polymorphisms in patients treated with preoperative DCF chemotherapy.

METHODS

A total of 158 patients were investigated for their absolute neutrophil count (ANC) within the first cycle of DCF chemotherapy at the National Cancer Center (NCC) Hospital East. DNA samples obtained from the NCC Biobank Registry were used for the analysis of nine genetic polymorphisms related to docetaxel pharmacokinetics. These genotypes were evaluated for their association with severe neutropenia, and further their risk factors were examined using a multivariate logistic regression.

RESULTS

A total 81 (51.3%) patients developed severe neutropenia. Multivariate analysis revealed that age (OR 1.054; CI 1.008-1.102, P = 0.022), baseline ANC (OR 1.019; CI 1.002-1.037, P = 0.030), ABCB1 3435C>T (OR 2.191; CI 1.087-4.417, P = 0.028) and ABCC2 *+9383C>G (OR 2.342; CI 1.108-4.948, P = 0.026) were significant risk factors for severe neutropenia development. The results from this study showed that age, ANC, ABCB1 3435C>T, and ABCC2 *+9383 G>C increased the incidence of severe neutropenia with the number of identified risk factors.

CONCLUSIONS

In addition to age and baseline ANC, ABCB1 3435C>T and ABCC2 *+9383C>G were identified as independent predictors for severe neutropenia in esophageal cancer patients treated with DCF chemotherapy.

Acid-sensitive PEGylated paclitaxel prodrug nanoparticles for cancer therapy: Effect of PEG length on antitumor efficacy

Paclitaxel is one of the most widely used anticancer agents, but strong side effects and low bioavailability limit its clinical efficacy. The use of tumor microenvironment-responsive prodrugs is promising to solve these problems, and a smart linkage is crucial to achieve the efficient release of paclitaxel from such prodrugs in tumor. Herein, an acid-responsive acetone-based acyclic ketal linkage is used to construct paclitaxel prodrugs with different length of poly(ethylene glycol) (PEG). The PEGylated acetone-based acyclic-ketal-linked prodrugs of paclitaxel (PKPs) self-assembled into nanoparticles that were stable in normal physiological environment but released paclitaxel rapidly in mildly acidic environment in tumor. The length of PEG had considerable impact on size and critical micelle concentration of PKP nanoparticles, thereby affecting prodrug hydrolysis kinetics, pharmacokinetics, biodistribution, and antitumor activity for PKP nanoparticles. In an A2780 xenograft mouse model, PKP nanoparticles displayed improved pharmacokinetics and superior antitumor efficacy against Taxol. Our results demonstrate that acyclic-ketal-based prodrugs are useful for the development of acid-responsive anticancer nanomedicines.

Paclitaxel, Imatinib and 5-Fluorouracil Increase the Unbound Fraction of Flucloxacillin In Vitro

Flucloxacillin (FLU), an isoxazolyl penicillin, is widely used for the treatment of different bacterial infections in intensive care units (ICU). Being highly bound to plasma proteins, FLU is prone to drug-drug interactions (DDI) when administered concurrently with other drugs. As FLU is binding to both Sudlow’s site I and site II of human serum albumin (HSA), competitive and allosteric interactions with other drugs, highly bound to the same sites, seem conceivable. Knowledge about interaction(s) of FLU with the widely used anticancer agents paclitaxel (PAC), imatinib (IMA), and 5-fluorouracil (5-FU is scarce. The effects of the selected anticancer agents on the unbound fraction of FLU were evaluated in pooled plasma as well as in HSA and α-1-acid glycoprotein (AGP) samples, the second major drug carrier in plasma. FLU levels in spiked samples were analyzed by LC-MS/MS after ultrafiltration. Significant increase in FLU unbound fraction was observed when in combination with PAC and IMA and to a lesser extent with 5-FU. Furthermore, significant binding of FLU to AGP was observed. Collectively, this is the first study showing the binding of FLU to AGP as well as demonstrating a significant DDI between PAC/IMA/5-FU and FLU.

Novel Thermosensitive Polymer-Modified Liposomes as Nano-Carrier of Hydrophobic Antitumor Drugs

Thermo-sensitive polymer-modified liposomes are able to achieve site-specific delivery of drugs. In this work, thermo-sensitive polymers were synthesized by atomic transfer radical polymerization of N-isopropyl acrylamide (NIPAAm) and N,N-dimethyl acrylamide (DMAAm) using bromoisobutyryl distearoyl phosphoethanolamine (DSPE-Br) as initiator. The resulting PNIPAAm-DSPE and P(NIPAAm-DMAAm)-DSPE polymers were characterized using proton nuclear magnetic resonance, Fourier transform infrared, and ultraviolet-visible spectroscopy. PNIPAAm-DSPE and P(NIPAAm-DMAAm)-DSPE exhibit a lower critical solution temperature of 34.0 and 46.9°C in water, and 29.8 and 38.8°C in phosphate buffered saline, respectively. Paclitaxel-loaded thermo-sensitive liposomes were prepared using film hydration method, followed by post-insertion of P(NIPAAm-DMAAm)-DSPE into the liposome bilayer. Drug release of traditional and thermosensitive liposomes was comparatively studied at 37 and 40°C. The total release and release rate of thermosensitive liposomes at 40°C were much higher than those at 37°C. And drug release is higher for thermosensitive liposomes than for traditional liposomes because insertion of thermo-sensitive polymer chains affects the system's stability. MTT assay showed that thermo-sensitive liposomes present no cytotoxicity to L929 cells at the tested concentrations, and paclitaxel-loaded liposomes have significant cytotoxicity against A549 cancer cells. Therefore, it is concluded that P(NIPAAm-DMAAm)-DSPE modified thermo-sensitive liposomes could be promising as nano-carrier of antitumor drugs.

Enhanced docetaxel delivery using sterically stabilized RIPL peptide-conjugated nanostructured lipid carriers: In vitro and in vivo antitumor efficacy against SKOV3 ovarian cancer cells

Docetaxel (DTX) has poor solubility, low specificity, and severe side effects. For efficient targeting of DTX to hepsin-overexpressing SKOV3 ovarian cancer cells, PEGylated and RIPL peptide (IPLVVPLRRRRRRRRC)-conjugated nanostructured lipid carriers (PEG-RIPL-NLCs) were examined for in vitro and in vivo antitumor efficacy. DTX-loaded plain NLCs (DTX-pNLCs), RIPL-NLCs (DTX-RIPL-NLCs), and PEG-RIPL-NLCs (DTX-PEG-RIPL-NLCs) were prepared using a solvent emulsification-evaporation technique. DTX was successfully loaded with high encapsulation efficiency (>93%), and all NLCs showed homogeneous dispersion with zeta potentials varying from -17 to 15 mV. Drug release was biphasic: initial rapid release, then gradual release. In vitro cytotoxicity was time- and dose-dependent: DTX-RIPL-NLCs and DTX-PEG-RIPL-NLCs exhibited greater cytotoxicity, enhanced cell apoptosis owing to the cell cycle arrest in the G2/M phase, and increased activation of the mitochondria-related intrinsic apoptosis pathway compared to DTX-pNLCs. Pharmacokinetic experiments in male Sprague-Dawley rats revealed that DTX-PEG-RIPL-NLCs increased the mean residence time of DTX but reduced total body clearance and volume of distribution. In a SKOV3-bearing xenograft Balb/c athymic mouse model, DTX-PEG-RIPL-NLCs suppressed tumors, evidenced by tumor volume change and histopathological examination. Thus, we conclude that PEG-RIPL-NLCs have an advantage of high payload of poorly water-soluble drugs and are a good candidate for drug targeting to SKOV3-derived ovarian cancer.

Paclitaxel for treatment of advanced small cell lung cancer (SCLC): a retrospective study of 185 patients

Background

Etoposide-/platinum-based chemotherapy is the standard first-line treatment for extensive-disease small cell lung cancer (SCLC), but responses are short-lived and subsequent options limited. Here, we present our experience with paclitaxel in advanced treatment lines.

Methods

We retrospectively studied the clinical course of all paclitaxel-treated SCLC patients between 2005 and 2015 in our institution. Prognostic and predictive factors were analyzed by Kaplan-Meier and Cox regression analyses.

Results

A total of 185 patients [119 men, median age 65 years, median ECOG performance status (PS) 1] were identified. One hundred and sixty-eight patients had extensive disease (ED) at the time of paclitaxel therapy. Paclitaxel was mainly given as third- or fourth-line therapy (93%). The response rate (RR) was 17% and disease control rate (DCR) 28%. Patients reached a median progression-free survival (PFS) of 1.6 (95% CI: 1.4-1.8) months and median overall survival (OS) of 3.3 (95% CI: 2.8-3.9) months. Main toxicities were fatigue (25%) and polyneuropathy (17%). Dose reduction of ≥25% was associated with shorter PFS [1.9 (95% CI: 1.5-2.3) vs. 1.4 (95% CI: 1.3-1.5) months; P=0.004]. Further independent predictive factors for PFS were gender, age, and hepatic/brain metastases (P<0.05). Tumor response to paclitaxel, PS, number and location of metastases, dose reduction, and smoking history were significant factors for OS in univariable analyses (P<0.05), while PS, dose reduction, status of cerebral/hepatic metastases, tumor response, and smoking history were retained as independent prognostic factors in multivariable testing. Notably, ECOG PS 2 patients had toxicity rates similar to ECOG PS 0-1 patients (63% vs. 62%), as well as a comparable DCR (29% vs. 28%), which was associated with prolonged survival (4.5 vs. 3.2 months for refractory cases, P=0.034).

Conclusions

Paclitaxel has clinically relevant activity in heavily pretreated SCLC. While patients with good PS and no cerebral/hepatic metastases derive the greatest benefit, ECOG PS 2 per se should not be used as a criterion to exclude patients.