Clinical, toxicological and pharmaceutical aspects of the antineoplastic drug taxol: a review

Advancements in the Cultivation, Active Components, and Pharmacological Activities of Taxus mairei

Taxus mairei (Lemée and H.Lév.) S.Y.Hu, indigenous to the southern regions of China, is an evergreen tree belonging to the genus Taxus of the Taxaceae family. Owing to its content of various bioactive compounds, it exhibits multiple pharmacological activities and has been widely applied in clinical medicine. This article comprehensively discusses the current state of cultivation, chemical constituents, applications in the pharmaceutical field, and the challenges faced by T. mairei. The paper begins by detailing the ecological distribution of T. mairei, aiming to provide an in-depth understanding of its origin and cultivation overview. In terms of chemical composition, the article thoroughly summarizes the extracts and monomeric components of T. mairei, unveiling their pharmacological activities and elucidating the mechanisms of action based on the latest scientific research, as well as their potential as lead compounds in new drug development. The article also addresses the challenges in the T. mairei research, such as the difficulties in extracting and synthesizing active components and the need for sustainable utilization strategies. In summary, T. mairei is a rare species important for biodiversity conservation and demonstrates significant research and application potential in drug development and disease treatment.

Markhamia lutea leaves aqueous and ethanolic extract with curative anti-inflammatory activity attenuates paclitaxel toxicity in rat's intestine

OBJECTIVES

Markhamia lutea (M. lutea, Bignoniaceae) is mainly found in tropical/neotropical regions of America, Africa and Asia. The plant's leaves, stems or roots are used to treat anaemia, bloody diarrhoea, parasitic and microbial infections. This study evaluates anti-inflammatory properties (in vitro) of Markhamia lutea and their curative effects on paclitaxel-induced intestinal toxicity (in vivo).

METHODS

The anti-inflammatory potential of Markhamia lutea was tested over cytokines (TNF-alpha, IL-6, IL-1β, IL-10), reactive oxygen species (ROS) and enzymes (cyclooxygenase and 5-lipoxygenase). While in vivo, intestinal toxicity was induced for 10 days by oral administration of paclitaxel (3 mg/kg, 0.05 mL). Animals in each group were further treated with aqueous (300 mg/kg) and ethanolic (300 mg/kg) leaves extracts of Markhamia lutea during 7 days and clinical symptoms were recorded, hematological, biochemical and histological analysis were subsequently performed.

RESULTS

In vitro, aqueous (250 μg/mL) and ethanolic (250 μg/mL) extracts of Markhamia lutea inhibited the activities of cyclooxygenase 1 (56.67 % and 69.38 %), cyclooxygenase 2 (50.67 % and 62.81 %) and 5-lipoxygenase (77.33 % and 86.00 %). These extracts inhibited the production of intracellular ROS, extracellular ROS and cell proliferation with maximum IC50 of 30.83 μg/mL, 38.67 μg/mL and 19.05 μg/mL respectively for the aqueous extract, then 25.46 μg/mL, 27.64 μg/mL and 7.34 μg/mL respectively for the ethanolic extract. The extracts also inhibited the production of proinflammatory cytokines (TNFα, IL-1β and IL-6) and stimulated the production of anti-inflammatory cytokines (IL-10). In vivo, after administration of paclitaxel, the aqueous and ethanolic extracts of Markhamia lutea significantly reduced the weight loss, the diarrheal stools and the mass/length intestines ratio of the treated animals compared to the animals of the negative control group. Biochemically, the extracts lead to a significant drop in serum creatinine and alanine aminotransferase levels, followed by a significant increase in alkaline phosphatase. In addition to bringing the haematological parameters back to normal values after disturbance by paclitaxel, the extracts caused tissue regeneration in the treated animals.

CONCLUSIONS

In vitro, aqueous and ethanolic extracts of Markhamia lutea showed anti-inflammatory properties (inhibition of COX1, COX2, 5-LOX activities, inhibition of ROS production and cell proliferation); in vivo, the same extracts showed curative properties against intestinal toxicity caused by paclitaxel.

Genomewide Expression Profiling Identifies a Novel miRNA-based Signature for the Detection of Peritoneal Metastasis in Patients With Gastric Cancer

OBJECTIVE

This study aimed to conduct a genomewide transcriptomic profiling to develop a microRNA (miRNA)-based signature for the identification of peritoneal metastasis (PM) in patients with gastric cancer (GC).

SUMMARY BACKGROUND DATA

Even though PM in patients with GC has long been recognized to associate with poor prognosis, currently there is lack of availability of molecular biomarkers for its robust diagnosis.

METHODS

We performed a systematic biomarker discovery by analyzing miRNA expression profiles in primary tumors from GC patients with and without PM, and subsequently validated the expression of candidate miRNA biomarkers in 3 independent clinical cohorts of 354 patients with advanced GC.

RESULTS

Five miRNAs (miR-30a-5p, -134-5p, -337-3p, -659-3p, and -3917) were identified during the initial discovery phase; three of which (miR-30a-5p, -659-3p, and -3917) were significantly overexpressed in the primary tumors from PM-positive patients in the testing cohort (P = 0.002, 0.04, and 0.007, respectively), and distinguished patients with versus without peritoneal metastasis with the value of area under the curve (AUC) of 0.82. Furthermore, high expression of these miRNAs also associated with poor prognosis (hazard ratio = 2.18, P = 0.04). The efficacy of the combination miRNA signature was subsequently validated in an independent validation cohort (AUC = 0.74). Finally, our miRNA signature when combined together with the macroscopic Borrmann's type score offered a much superior diagnostic in all 3 cohorts (AUC = 0.87, 0.76, and 0.79, respectively).

CONCLUSIONS

We have established an miRNA-based signature that have a potential to identify peritoneal metastasis in GC patients.

Paclitaxel-Induced Bowel Perforation: A Rare Cause of Acute Abdomen

Paclitaxel, a chemotherapeutic agent, is routinely administered for the treatment of various solid organ malignancies. In rare instances, patients receiving infusions of paclitaxel may present with signs of an acute abdomen. Ischemia and necrosis of the bowel wall from chemotherapy-induced neutropenia and direct toxic effects of the drug have been implicated as the cause. We present a case of necrotizing small and large bowel perforation in a patient with breast cancer, 2 weeks after paclitaxel administration.

Clinical characteristics of colitis induced by taxane-based chemotherapy

Background:

Limited data are available concerning the clinical features of toxic gastrointestinal (GI) effects of taxane-based therapy. We describe the clinical, endoscopic and histologic features of taxane-induced colitis.

Methods:

This retrospective study included cancer patients who received taxane therapy and underwent colonoscopy for GI symptoms from 2000-2018.

Results:

Of the 45,527 patients who received taxane therapy during the study period, 76 (0.2%) met the inclusion criteria. Most patients (54%) received paclitaxel, 37% docetaxel, and 9% nab-paclitaxel. The median time from taxane therapy initiation to colitis symptom onset was 31 days. The median duration of colitis symptoms was 30 days. Colitis treatment comprised immunosuppressive therapy in 8 patients (11%), antibiotics in 17 (22%), antimotility agents in 18 (24%), and octreotide or somatostatin in 2 (3%). Thirty-five patients (46%) required hospitalization and seven (9%) required admission to the intensive care unit (ICU). Endoscopy revealed mucosal ulceration in 19 patients (25%), nonulcerative inflammation in 32 (42%), and normal findings in 25 (33%). Seventeen patients (22%) had features of lymphocytic colitis. One patient had spontaneous colonic perforation that required surgical intervention. Colitis symptoms recurred in 7 patients (9%) after initial improvement. Patients who received nab-paclitaxel developed GI toxicity earlier (P=0.003), required colitis-related hospitalization more frequently (P=0.005), and received intravenous fluids more frequently (P=0.025), compared with patients who received other taxanes.

Conclusions:

Taxane-related colitis can present with significant inflammation on colonoscopy, and in a minority of patients as microscopic colitis. Taxane-induced colitis, although uncommon, can lead to ICU admission and colonic perforation.

Hierarchically Self-Assembled Supramolecular Host-Guest Delivery System for Drug Resistant Cancer Therapy

In this report, a new star-like copolymer β-CD- g-(PNIPAAm- b-POEGA) x, consisting of a β-CD core, grafted with temperature-responsive poly( N-isopropylacrylamide) (PNIPAAm) and biocompatible poly(oligo(ethylene glycol) acrylate) (POEGA) in a block copolymer of the arms, was used to deliver chemotherapeutics to drug resistant cancer cells and tumors. The first step of the self-assembly process involves the encapsulation of chemotherapeutics through host-guest inclusion complexation between the β-cyclodextrin cavity and the anticancer drug. Next, the chain interaction of the PNIPAAm segment at elevated temperature drives the drug-loaded β-CD- g-(PNIPAAm- b-POEGA) x/PTX inclusion complex to hierarchically self-assemble into nanosized supramolecular assemblies at 37 °C, whereas the presence of poly(ethylene glycol) (PEG) chains in the distal end of the star-like copolymer arms impart enhanced stability to the self-assembled structure. More interestingly, this supramolecular host-guest nanocomplex promoted the enhanced cellular uptake of chemotherapeutics in MDR-1 up-regulated drug resistant cancer cells and exhibited high therapeutic efficacy for suppressing drug resistant tumor growth in an in vivo mouse model, due to the increased stability, improvement in aqueous solubility, enhanced cellular uptake, and partial membrane pump impairment by taking the advantage of PEGylation and supramolecular complex between this star-like copolymer and chemotherapeutics. This work signifies that temperature-sensitive PEGylated supramolecular nanocarriers with good biocompatibility are effective in combating MDR-1 mediated drug resistance in both in vitro and in vivo models, which is of significant importance for the advanced drug delivery platform designed to combat drug resistant cancer.

Cytotoxicity of Tanshinone IIA combined with Taxol on drug-resist breast cancer cells MCF-7 through inhibition of Tau

Drug resistance represents a major obstacle to improving the overall response and survival of cancer patients. Taxol is one of the most commonly used chemotherapy agents in breast cancer. As with many cancer therapeutic agents, resistance remains a significant problem when using Taxol to treat malignancies. In this study, estrogen receptor positive breast cancer cells MCF-7 were induced Taxol resistance. And Tanshinone IIA combined with Taxol was chosen to treat it. The drugs combination showed additive effect in most drug concentrations. Drug resistance cancer cells showed a higher microtubule associated protein (Tau) expression, which was considered as one of the reasons for Taxol resistance. Tanshinone IIA inhibited the expression of Tau in MCF-7 cells and resulted in higher sensibility of Taxol. Moreover, Tanshinone IIA also showed cytotoxicity to MCF-7, which might be related to its estrogenicity effect. In conclusion, the combination of Tanshinone IIA and Taxol showed higher cytotoxicity to Taxol resistant MCF-7 cells, which might be related to the inhibition of Tau.

Nanomedicine safety in preclinical and clinical development: focus on idiosyncratic injection/infusion reactions

Injection/infusion reactions to nanopharmaceuticals (and particulate drug carriers) are idiosyncratic and well documented. The molecular basis of nanoparticle-mediated injection reactions is debatable, with two hypotheses as front-runners. The first is complement-activation-related 'pseudoallergy', where a causal role for nanoparticle-mediated complement activation in injection/infusion reactions is considered. However, the second hypothesis (the rapid phagocytic response hypothesis) states a transitional link from robust clearance of nanoparticles (NPs) from the blood by strategically placed responsive macrophages to adverse hemodynamic and cardiopulmonary reactions, regardless of complement activation. Here, I critically examine and discuss these hypotheses. Current experimentally derived evidence appears to be more in support of the rapid phagocytic response hypothesis than of the 'pseudoallergy' hypothesis.

Development and qualification of an LC-MS/MS method for investigating the biological implications of micelle entrapped paclitaxel in cell culture and rats

Paclitaxel is a front-line antineoplastic drug used in chemotherapeutic modalities for treatment of various types of malignancies. However, its efficacy is limited by dose-related toxicities. In this study, we have explored two important biological aspects of entrapping paclitaxel in PEG₂₀₀₀ -DSPE micelles. First, we evaluated the impact of this micellar delivery system on P-glycoprotein (P-gp)-paclitaxel interaction, and we investigated differences in plasma pharmacokinetics of free and micelle-entrapped paclitaxel. For quantification of paclitaxel, an LC-MS/MS method was developed. Paclitaxel was extracted from samples using a simple one-step protein precipitation. Chromatographic conditions included a C₁₈ column with a mobile phase consisting of 0.1% formic acid in acetonitrile-water (60:40, v/v) pumped at 1 mL/min. The lower limit of quantitation in both plasma and cell lysate was 1.0 ng/mL. The quantitative linear range was 1-1000 ng/mL. In addition, P-gp efflux studies on free and micellar paclitaxel showed the proficiency of PEG₂₀₀₀ -DSPE micelles in evading P-gp-mediated efflux, thus increasing paclitaxel uptake. Furthermore, the micellar paclitaxel levels were maintained in the body for longer time as compared with taxol, which is desirable for increasing the efficacy of paclitaxel in cancer treatment.

Paclitaxel inhibits the hyper-activation of spleen cells by lipopolysaccharide and induces cell death

Paclitaxel was isolated from the bark of the Pacific yew, Taxus brevifolia, and used as an anticancer agent. Paclitaxel prevents cancer cell division by inhibiting spindle fiber function, inducing cell death. A recent study demonstrated that paclitaxel binds to myeloid differentiation protein-2 of Toll-like receptor 4 and prevents the signal transduction of lipopolysaccharide (LPS). Paclitaxel converts immune cells hypo-responsive to LPS. In this study, we investigated whether paclitaxel can inhibit the phenotype and function of immune cells. To accomplish this, we used spleen cells, a major type of immune cell, LPS, a representative inflammatory agent and a mitogen for B lymphocytes. LPS profoundly increased the activation and cytokine production of spleen cells. However, paclitaxel significantly inhibited LPS-induced hyper-activation of spleen cells. Furthermore, we found that paclitaxel induced cell death of LPS-treated spleen cells. These results suggest that paclitaxel can inhibit the hyper-immune response of LPS in spleen cells via a variety of mechanisms. These findings suggest that paclitaxel can be used as a modulating agent for diseases induced by hyper-activation of B lymphocytes. Taken together, these results demonstrate that paclitaxel inhibits the function of spleen cells activated by LPS, and further induces cell death.

Recent advances of cocktail chemotherapy by combination drug delivery systems

Combination chemotherapy is widely exploited for enhanced cancer treatment in the clinic. However, the traditional cocktail administration of combination regimens often suffers from varying pharmacokinetics among different drugs. The emergence of nanotechnology offers an unparalleled opportunity for developing advanced combination drug delivery strategies with the ability to encapsulate various drugs simultaneously and unify the pharmacokinetics of each drug. This review surveys the most recent advances in combination delivery of multiple small molecule chemotherapeutics using nanocarriers. The mechanisms underlying combination chemotherapy, including the synergistic, additive and potentiation effects, are also discussed with typical examples. We further highlight the sequential and site-specific co-delivery strategies, which provide new guidelines for development of programmable combination drug delivery systems. Clinical outlook and challenges are also discussed in the end.

Gossypol: phytoalexin of cotton

Sesquiterpenoids are a class of 15-carbon secondary metabolites that play diverse roles in plant adaptation to environment. Cotton plants accumulate a large amount of sesquiterpene aldehydes (including gossypol) as phytoalexins against pathogens and herbivores. They are stored in pigment glands of aerial organs and in epidermal layers of roots. Several enzymes of gossypol biosynthesis pathway have been characterized, including 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and farnesyl diphosphate synthase (FPS) that catalyze the formation of the precursor farnesyl diphosphate (FPP), (+)-δ-cadinene synthase (CDN) which is the first enzyme committed to gossypol biosynthesis, and the downstream enzymes of CYP706B1 and methyltransferase. Expressions of these genes are tightly regulated during cotton plants development and induced by jasmonate and fungi elicitors. The transcription factor GaWRKY1 has been shown to be involved in gossypol pathway regulation. Recent development of new genomic platforms and methods and releases of diploid and tetraploid cotton genome sequences will greatly facilitate the elucidation of gossypol biosynthetic pathway and its regulation.

The Role of TLR4 in Chemotherapy-Driven Metastasis

Tumor resistance to cytotoxic drugs is one of the main obstacles to successful cancer therapy. Emerging evidence suggests that chemoresistance is promoted by substances released from dead and damaged cells that activate the host repair program orchestrated by Toll-like receptor-4 (TLR4). TLR4 is often overexpressed in malignant and tumor-infiltrating immune cells. In addition to endogenous ligands released by therapy-induced tumor destruction, TLR4 is directly activated by paclitaxel, one of the most commonly used chemotherapeutic drugs against various human cancers. TLR4 activation promotes local and systemic inflammation, leading to induction of multiple circuits that create a regenerative environment favoring local recurrence and metastasis. Of particular importance is TLR4-mediated recruitment of endothelial progenitors derived from immature myeloid cells. These cells play a major role in rebuilding tumor-associated lymphatic and blood vessels, thereby promoting lymphatic and hematogenous metastasis. The latter is further enhanced by the premetastatic niche generated by mobilization of myeloid provascular cells to distant organs. This review summarizes the recent evidence demonstrating that paclitaxel and other clinically used anticancer drugs actively induce metastasis even while shrinking the primary tumor. Better understanding of the mechanisms underlying TLR4-dependent chemotherapy-driven metastasis might be the key to overcoming challenges of cancer eradication.

Identification of Chinese herbal medicines by fluorescence microscopy: fluorescent characteristics of medicinal bark

Medicinal bark refers to structures outside the vascular cambium of stems, branches and roots of gymnospermous and dicotyledonous plants that are used as medicinal materials; bark is an important type of Chinese herbal medicine. However, identification of the species from which the bark comes can be very difficult, especially when the bark is dried and sliced. In our previous studies, we have found that fluorescence microscopy is a powerful tool for the identification of easily confused Chinese herbal medicines, powdered Chinese herbal medicines and decoction dregs. To establish the fluorescent characteristics by which medicinal barks can be identified, for ensuring their safe and effective use, a systematic microscopic investigation by normal light and fluorescence microscope was carried out on transverse section samples of 11 medicinal barks commonly used in China. Specifically, the fluorescent characteristics of mechanical tissues, including stone cells and fibres as well as secretory tissues, have been observed. The microscopic features of medicinal bark are here systematically and comparatively described and illustrated. Under the fluorescence microscope, various tissues emitted fluorescence of different colours, and we found that both the colours and the intensity can be used to distinguish and identify these barks.

Direct comparison of two albumin-based paclitaxel-loaded nanoparticle formulations: is the crosslinked version more advantageous?

Nanoparticles using albumin as particle matrix have entered the mainstream of drug delivery. It was reported that non-crosslinked albumin nanoparticles were unstable in circulation and could deliver drugs into tumor through gp60/SPARC pathway; in contrast, the delivery of drugs with stable nanoparticles was dependent on enhanced permeability and retention effect. Thus, it is questionable which kind of nanoparticles was more advantageous. Two versions of albumin-bound paclitaxel nanoparticles were prepared. In vitro, the non-crosslinked particles could rapidly disintegrate and the crosslinked was stable. The pharmacokinetics of both formulations was different especially at early time and the non-crosslinked particles were cleared rapidly. After non-crosslinked particle treatment paclitaxel had a tendency to accumulate into heart and kidney and following therapy with the crosslinked particles, paclitaxel was liable to be delivered into lung, spleen and liver. The delivery efficiency of paclitaxel into tumor following the non-crosslinked particle treatment was greater than that of the crosslinked (p<0.05), thus resulting in a considerably improved antineoplastic activity. Moreover, the non-crosslinked formulation was only slightly more toxic. It was concluded that the non-crosslinked formulation was more advantageous for the delivery of paclitaxel and our conclusion might be generalized to other lipophilic drugs delivered with albumin nanoparticles.

Genomic perspectives in inter-individual adverse responses following nanomedicine administration: The way forward

The underlying mechanism of intravenous infusion-related adverse reactions inherent to regulatory-approved nanomedicines still remains elusive. There are substantial inter-individual differences in observed adverse reactions, which may include cardiovascular, broncho-pulmonary, muco-cutaneous, neuro-psychosomatic and autonomic manifestations. Although nanomedicine-mediated triggering of complement activation has been suggested to be a significant contributing factor to these adverse events, complement activation may still proceed in non-responders. Whether these reactions share similar immunological mechanisms and underpinning genetic factors with drug hypersensitivity syndrome remains to be investigated. Genetic association studies could be a powerful tool to dissect causative factors and reveal the multiple molecular pathways that induce infusion related adverse reactions. It is envisaged that such research may lead to the design of reliable in vitro profiling tests for risk assessment and treatment decisions, thereby revolutionizing the practice of medicine with nanopharmaceuticals. Such procedures may further improve regulatory approval processes for nanomedicines currently in the pipeline and decrease the overall cost of health care. Here we discuss some key innate immunity genes and their polymorphisms in relation to nanomedicine infusion-mediated symptomatic responses.

Development of a rat model of oral small molecule receptor tyrosine kinase inhibitor-induced diarrhea

Orally administered small molecule receptor tyrosine kinase inhibitors (RTKIs) are increasingly common treatments for cancer, both alone and in combination with chemotherapy. However, their side effect profiles and the underlying mechanisms of such are not yet fully elucidated. Management of their most common dose limiting side effect, diarrhea, has been hampered by a lack of suitable animal models. We aimed to develop a clinically relevant rat model of RTKI-induced diarrhea that could be utilized for investigating supportive care interventions and pharmacokinetics. Albino Wistar rats were treated daily for 4 weeks with various concentrations of lapatinib to determine the optimal dose for development of diarrhea. This was then followed by an experiment with addition of paclitaxel once weekly for 4 weeks to observe effects of combination drug treatment on diarrhea. Data regarding animal tolerance to the treatment, organ weights, circulating lapatinib concentration and histopathology were collected weekly. Lapatinib caused diarrhea in rats that was dose-dependent. Diarrhea occurred without causing significant intestinal histopathology. Follow up experiments are currently underway to determine the exact pathogenesis and mechanisms of lapatinib-induced diarrhea and potential protective strategies.

Activation of complement by therapeutic liposomes and other lipid excipient-based therapeutic products: prediction and prevention

Some therapeutic liposomes and lipid excipient-based anticancer drugs are recognized by the immune system as foreign, leading to a variety of adverse immune phenomena. One of them is complement (C) activation, the cause, or major contributing factor to a hypersensitivity syndrome called C activation-related pseudoallergy (CARPA). CARPA represents a novel subcategory of acute (type I) hypersensitivity reactions (HSR), which is mostly mild, transient, and preventable by appropriate precautions. However, in an occasional patient, it can be severe or even lethal. Because a main manifestation of C activation is cardiopulmonary distress, CARPA may be a safety issue primarily in cardiac patients. Along with an overview of the various types of liposome-immune system interactions, this review updates the experimental and clinical information on CARPA to different therapeutic liposomes and lipid excipient-based (micellar) anticancer drugs, including PEGylated liposomal doxorubicin sulfate (PLD, Doxil®) and paclitaxel (Taxol®). The substantial individual variation of in vitro and in vivo findings reflects an extremely complex immune phenomenon involving multiple, redundant pathways of C activation, signal transduction in allergy-mediating cells and vasoactive mediator actions at the effector cell level. The latest advances in this field include the proposal of doxorubicin-induced shape changes and aggregation of liposomes in Doxil as possible contributing factors to CARPA caused by PLD, and the finding that Doxil-induced immune suppression prevents HSR to co-administered carboplatin, a significant benefit of Doxil in combination chemotherapy with carboplatin. The review evaluates the use of in vitro C assays and the porcine liposome-induced cardiopulmonary distress model for predicting CARPA. It is concluded that CARPA may become a frequent safety issue in the upcoming era of nanomedicines, necessitating its prevention at an early stage of nanomedicine R&D.

Medicinal plants used as antitumor agents in Brazil: an ethnobotanical approach

WE DESCRIBE THE MEDICINAL PLANTS THAT HAVE BEEN REPORTED TO BE ANTITUMOR AGENTS AND THAT HAVE BEEN USED IN ETHNOBOTANIC RESEARCH IN BRAZIL TO ANSWER THE FOLLOWING QUESTIONS: what is the abundance of plants reported to be antitumor in Brazil? Have the plant species used for tumor treatment in traditional Brazilian medicine been sufficiently examined scientifically? Our analysis included papers published between 1980 and 2008. A total of 84 medicinal plant species were reported to be used for cancer and tumor prevention or treatment; 69.05% of these were cited as being used for the treatment of tumors and cancer in general and 30.95% for specific tumors or cancers. The plants that were cited at a higher frequency were Aloe vera, Euphorbia tirucalli, and Tabebuia impetiginosa. At least, one pharmacological study was found for 35.71% of the species. Majority of the studies selected were conducted in rural communities and urban areas and in areas with traditional healers in Brazil. We found the following molecules to be the most studied in vitro and in vivo: silibinin, β-lapachone, plumbagin and capsaicin. The species addressed here constitute interesting objects for future studies to various professionals in the field of natural products.

Acute and late onset cognitive dysfunction associated with chemotherapy in women with breast cancer

BACKGROUND

Growing evidence supports cognitive dysfunction associated with standard dose chemotherapy in breast cancer survivors. We determined the incidence, nature, and chronicity of cognitive dysfunction in a prospective longitudinal randomized phase 3 treatment trial for patients with T1-3, N0-1, M0 breast cancer receiving 5-fluorouracil, doxorubicin, and cyclophosphamide with or without paclitaxel.

METHODS

Forty-two patients underwent a neuropsychological evaluation including measures of cognition, mood, and quality of life. Patients were scheduled to be assessed before chemotherapy, during and shortly after chemotherapy, and 1 year after completion of chemotherapy.

RESULTS

Before chemotherapy, 21% (9 of 42) evidenced cognitive dysfunction. In the acute interval, 65% (24 of 37) demonstrated cognitive decline. At the long-term evaluation, 61% (17 of 28) evidenced cognitive decline after cessation of treatment. Within this group of patients, 71% (12 of 17) evidenced continuous decline from the acute interval, and, notably, 29% (5 of 17) evidenced new delayed cognitive decline. Cognitive decline was most common in the domains of learning and memory, executive function, and processing speed. Cognitive decline was not associated with mood or other measured clinical or demographic characteristics, but late decline may be associated with baseline level of performance.

CONCLUSIONS

Standard dose systemic chemotherapy is associated with decline in cognitive function during and shortly after completion of chemotherapy. In addition, delayed cognitive dysfunction occurred in a large proportion of patients. These findings are consistent with a developing body of translational animal research demonstrating both acute and delayed structural brain changes as well as functional changes associated with common chemotherapeutic agents such as 5-fluorouracil.

Nanostructured silica materials as drug-delivery systems for Doxorubicin: single molecule and cellular studies

We apply mesoporous thin silica films with nanometer-sized pores as drug carriers and incorporate the widely used anticancer drug Doxorubicin. Through single-molecule based measurements, we gain mechanistic insights into the drug diffusion inside the mesoporous film, which governs the drug-delivery at the target-site. Drug dynamics inside the nanopores is controlled by pore size and surface modification. The release kinetics is determined and live-cell measurements prove the applicability of the system for drug-delivery. This study demonstrates that mesoporous silica nanomaterials can provide solutions for current challenges in nanomedicine.

Optimization of multidrug resistance 1 gene transfer confers chemoprotection to human hematopoietic cells engrafted in immunodeficient mice

OBJECTIVE

To investigate whether an optimization of MDR1 gene transfer protocol would result in stable hematopoietic stem cell (HSC) engraftment and myeloprotection in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice after paclitaxel chemotherapy.

METHODS

We transplanted freshly isolated CD34+ cells or MDR1-transduced CD34+ cells derived from human umbilical cord blood (UCB) into sublethally irradiated NOD/SCID mice. Twenty-eight days after transplantation, mice received paclitaxel chemotherapy and peripheral blood (PB) was collected for analysis of WBC, RBC and PLT counts once every week.

RESULTS

We found that MDR1-transduced human hematopoietic cells could facilitate hematopoietic recovery and completely reconstitute hematopoiesis in mice as well as freshly isolated CD34+ cells. Mice transplanted with MDR1-transduced human hematopoietic cells were protected from paclitaxel chemotherapy with higher survival rate and higher level of WBC counts and RBC counts compared with mice transplanted with untransduced HSCs. We also demonstrated that hematopoietic cells transduced with MDR1 gene were enriched in vivo after paclitaxel chemotherapy determined by the higher percentage of human Rh-123(dull) CD45+ cells in bone marrow of mice.

CONCLUSION

Our results demonstrated successful chemoprotection against myelosuppression in mice by MDR1-transduced repopulating human hematopoietic cells with an optimized transduction protocol.

Peripheral Neurotoxicity of Weekly Paclitaxel Chemotherapy: A Schedule or a Dose Issue?

PURPOSE

The rationale for intensification strategies is that more frequent exposure to chemotherapeutics could enhance antitumor activity. Several trials investigated weekly paclitaxel administration, but there are no clear data concerning peripheral neurotoxicity. The aim of this study was to assess the incidence of peripheral neurotoxicity in patients affected by advanced breast cancer treated with weekly paclitaxel.

PATIENTS AND METHODS

Neurotoxicity was assessed with neurologic and neurophysiologic evaluation before treatment and after 12 weeks and 24 weeks. A total neurotoxicity score was assigned to each patient on the basis of neurophysiologic and neuropathic signs and symptom changes. Seventeen patients entered the study.

RESULTS

After 12 weeks of treatment, 71% showed moderate clinical and/or neurophysiologic signs of neurotoxicity; after 24 weeks, the incidence of neurotoxicity increased to 96%. Sural amplitude at the 24-weeks examination significantly decreased from basal mean value (13.5 microv, standard deviation [SD] 6 microv vs. 7 microv, SD 5.9 microv, respectively; P = 0.01), whereas median sensory amplitude decreased after 24 weeks from 10.3 microv, SD 6.2 microv to 4.9 microv, SD 3.8 microv (P = 0.001). In a subset of 11 patients, we obtained a follow-up examination after 6 months from the end of treatment. In all patients, examined signs and symptoms of neurotoxicity improved with recovery of subjective neuropathic symptoms and neurophysiologic findings.

CONCLUSION

Our results demonstrate, in a little population of patients evaluated with a comprehensive neurologic assessment, that weekly paclitaxel is related to a very high incidence of peripheral neurotoxicity. Follow-up data obtained in a subset of patients indicate that peripheral neurotoxicity is reversible.

Encéphalopathie aiguë après injection de paclitaxel

INTRODUCTION

Paclitaxel is an anti-neoplastic agent commonly used in the treatment of primary bronchial carcinoma and tumours of the breast and ovary. Its toxicity, haematological and peripheral neuropathy, are well known. On the other hand central nervous system toxicity is rare.

CASE REPORT

We report a case of acute encephalopathy, occurring eight hours after infusion of Paclitaxel, in a patient treated for adenocarcinoma of the lung. It included drowsiness, confusion and hallucinations, and resolved completely after ten days. The diagnosis of encephalopathy secondary to Paclitaxel injection was reached after exclusion of other possible aetiologies.

CONCLUSIONS

Acute encephalopathy is a rare complication of intravenous Paclitaxel treatment. The pathophysiology of this toxic effect is discussed: a direct toxicity of Paclitaxel or of its solvent (polyoxethylated castor oil), and the role of a pre-existing alteration of the blood-brain barrier.

Does Paclitaxel (Taxol) Given after 111In-Labeled Monoclonal Antibodies Increase Tumor-Cumulated Activity in Epithelial Cancers?

PURPOSE

Paclitaxel synergized radiolabeled monoclonal antibodies, enhancing therapeutic effect in studies in mice with human xenografts. Paclitaxel was also observed to increase tumor uptake in imaging studies of (111)In-DOTA-Gly3Phe-m170 in patients with breast and prostate cancers. Further evaluations of tissue-cumulated activities, therapeutic indices, and pharmacokinetics were done using data for patients with breast and prostate cancer and for mice with human breast cancer xenografts.

EXPERIMENTAL DESIGN

In radioimmunotherapy trials, 12 patients with breast or prostate cancer were given two imaging doses (5 mCi each) of (111)In-DOTA-Gly3Phe-m170 1 week apart. Five of these patients were given a single dose of paclitaxel i.v. (75 mg/m2) 2 days after the second dose of (111)In. In a subsequent study, athymic mice with human breast cancer xenografts were given (111)In-DOTA-Gly3Phe-ChL6 alone, or in combination with daily paclitaxel i.p. (300 microg) one or more times. Pharmacokinetics were studied for at least 6 days in patients and 5 days in mice. Cumulated activities were determined for tumors and normal tissues.

RESULTS

Tumor-cumulated activity for every patient in the paclitaxel-treated group increased for the second dose of (111)In-DOTA-Gly3Phe-m170. The median ratio of cumulated activities in tumors for imaging dose 2 to those for dose 1 was 1.0 (0.8-1.3) in patients that were not given paclitaxel and 1.3 (1.2-1.4) in patients given paclitaxel. Normal tissue-cumulated activities were not different for the two doses. Mice given paclitaxel 1 day after (111)In-DOTA-Gly3Phe-ChL6 also showed an increase in tumor-cumulated activity, 22.9 (+/- 1.3) versus 19.4 (+/- 3.3) microCi h/g/microCi (P = 0.05). Cumulated activities of normal tissues were similar for all groups of mice.

CONCLUSIONS

Paclitaxel given 1 to 2 days after (111)In-DOTA-Gly3Phe-monoclonal antibody increased the tumor-cumulated activity in patients and in mice with epithelial cancers and did not alter cumulated activities in normal tissues.

Complement activation-related pseudoallergy: a new class of drug-induced acute immune toxicity

A major goal in modern pharmacotechnology is to increase the therapeutic index of drugs by using nanoparticulate vehicle systems in order to ensure slow release or targeted delivery of drugs. With all great benefits, however, these innovative therapies can carry a risk for acute immune toxicity manifested in hypersensitivity reactions (HSRs) that do not involve IgE but arises as a consequence of activation of the complement (C) system. These anaphylactoid reactions can be distinguished within the Type I category of HSRs as "C activation-related pseudoallergy" (CARPA). Drugs and agents causing CARPA include radiocontrast media (RCM), liposomal drugs (Doxil, Ambisome and DaunoXome) and micellar solvents containing amphiphilic lipids (e.g., Cremophor EL, the vehicle of Taxol). These agents activate C through both the classical and the alternative pathways, giving rise to C3a and C5a anaphylatoxins that trigger mast cells and basophils for secretory response that underlies HSRs. Pigs provide a useful model for liposome-induced CARPA as minute amounts of reactogenic lipomes cause C activation with consequent dramatic cardiovascular and laboratory abnormalities that mimic some of the human symptoms. Consistent with the causal role of C activation in liposome-induced HSRs, a recent clinical study demonstrated correlation between the formation of C terminal complex (SC5b-9) in blood and the presence of HSRs in patients treated with liposomal doxorubicin (Doxil). Overall, the CARPA concept may help in the prediction, prevention and treatment of the acute immune toxicity of numerous state-of-the-art drugs.

Incidence and risk factors for paclitaxel hypersensitivity during ovarian cancer chemotherapy

Hypersensitivity reaction (HSR) is still a major concern during cancer chemotherapy with paclitaxel. In the present study, we investigated retrospectively the incidence of HSRs to paclitaxel and the risk factors in 105 patients (553 courses) who received adjuvant chemotherapy (paclitaxel and carboplatin) for ovarian cancer. Moderate to severe HSRs that led to cessation or discontinuation of the chemotherapy, including respiratory distress and hypotension, were observed in 14 patients (13.3%) and 16 courses (2.9%), regardless of the use of conventional premedication with glucocorticoid, and histamine H(1) and H(2) antagonists. The incidence of HSRs to paclitaxel in patients with ovarian cancer seemed to be considerably higher than those reported by other investigators in patients with other carcinomas such as non-small-cell lung cancer and breast cancer. Four risk factors were identified: (1) history of mild dermal reactions such as facial flushing and urticaria in previous courses, (2) presence of respiratory dysfunction, (3) obesity (body mass index >25), and (4) postmenopausal at the time of ovariectomy. The incidence of hypersensitivity increased linearly as the number of risk factors increased (r=0.992, P=0.008). It is likely that disappearance of the estrous cycle facilitates the occurrence of HSRs to paclitaxel.

Low-dose weekly paclitaxel for recurrent or refractory aggressive non-Hodgkin lymphoma

BACKGROUND

Many patients with recurrent, intermediate or high-grade non-Hodgkin lymphoma (NHL) may not respond to or are not candidates for aggressive salvage chemotherapy. Effective, less toxic regimens are needed. Although high-dose taxanes have not been reported to be very effective for the treatment of lymphoma, different delivery rates may allow for different mechanisms of action to be manifest and result in a different toxicity profile and response rate. The current study tested this hypothesis by using low-dose, weekly paclitaxel in patients with recurrent or refractory NHL.

METHODS

Adults age > 18 years with refractory or recurrent, aggressive NHL who were not considered curable with standard high-dose therapy received paclitaxel at a dose of 80 mg/m2 weekly for 5 weeks for 2 cycles.

RESULTS

Thirty-four patients with refractory NHL and 4 patients with recurrent disease were treated. Approximately 45% of the patients had achieved a prior disease remission. The median number of prior regimens received was 3, 74% of the patients had an International Prognostic Index of > or = 3 at the time of study entry, and 29% had failed high-dose therapy with autologous hematopoietic support. Only one patient encountered severe toxicity (sepsis). Myelosuppression was reported to occur in approximately 20% of patients. A total of 10 patients (26%) achieved a complete disease response and 4 patients (11%) achieved a partial response.

CONCLUSIONS

In the current study, low-dose, weekly paclitaxel therapy was found to provide a well tolerated and less toxic approach to the treatment of refractory NHL, with encouraging responses noted in heavily pretreated patients. However, evaluation in patients with an earlier stage of disease is warranted.

Acute transient encephalopathy after paclitaxel infusion: report of three cases

Paclitaxel (Taxol) is a diterpene plant product and antineoplastic agent that promotes the assembly of microtubules as well as stabilizing their formation by preventing depolymerization. Myelosuppression was found to be dose-limiting, but peripheral neurotoxicity is also a well known side-effect. Central nervous system toxicity is rare, probably because paclitaxel does not cross the blood-brain barrier. We observed three patients who presented with acute encephalopathy within 6 h after infusion of paclitaxel at normal doses. All patients had received prior whole brain irradiation (WBI) and one patient had prior brain metastasectomy. Computer tomography and magnetic resonance imaging showed no evidence of cerebral metastases. An effect from other organ toxicities was excluded in all patients. All recovered spontaneously within 4-6 h. From this we can conclude that paclitaxel can cause severe acute transient encephalopathy, which may occur more frequently after prior WBI and/or surgery due to alteration of small vessel function.

An overview of chemotherapy-induced peripheral sensory neuropathy, focusing on oxaliplatin

When treating patients for metastatic cancer, there is always a balance between the benefits of treatment and resulting side-effects. Peripheral sensory neuropathy (PSN) is a side-effect of many anticancer agents used in routine practice. Oxaliplatin is a relatively new agent currently licensed in over 50 countries including France, Germany and the UK for the treatment of metastatic colorectal cancer. Although it is a new agent, it is from the same family of drugs as cisplatin, an agent that has been used for many years. PSN is the most commonly discussed side-effect associated with oxaliplatin. Oxaliplatin-induced PSN is characterized by two distinct syndromes: a transient acute dysaesthesia and a cumulative distal neurotoxicity. Importantly, both are generally reversible after stopping treatment. Oxaliplatin-induced acute PSN is triggered and exacerbated by cold and can be greatly reduced in affected patients simply by avoiding cold conditions. Oxaliplatin-induced cumulative PSN may also be managed by temporary cessation of treatment.

Griseofulvin potentiates antitumorigenesis effects of nocodazole through induction of apoptosis and G2/M cell cycle arrest in human colorectal cancer cells

In this study, we demonstrate that apoptosis and G2/M cell cycle arrest were easily induced by treatment with the oral-antifungal agent, griseofulvin (GF). The mechanisms of GF-induced G2/M arrest were characterized as (a) induction of abnormal mitotic spindle formation, (b) elevation of cyclin B1/cdc2 kinase activity and (c) down-regulation of myt-1 protein expression. On the other hand, caspase 3 activation, Bcl-2 hyperphosphorylation and inhibition of the normal function of Bcl-2 associated with Bax were demonstrated to be the mechanisms of GF-induced apoptosis. DNA fragmentation and flow cytometry analyses demonstrated that combined treatment of GF with the cancer chemotherapeutic agent, nocodazole (ND), strongly potentiates the apoptotic effect and arrest of the G2/M cell cycle in 5 types of human cancer cells, but not in normal human keratinocytes (#76 KhGH). The combined treatment of GF and ND triggered the polymerization of purified tubulin in HT 29 but not in #76 KhGH cells. To further confirm these observations, the therapeutic efficacy was further examined in vivo by treating athymic mice bearing COLO 205 tumor xenografts, with GF (50 mg/kg), ND (5 mg/kg) or GF + ND. Combined treatment of GF and ND significantly enhanced the effect of ND, and led to cessation of tumor growth. These results suggest that chemotherapeutic agents (such as ND) administered in the presence of GF might provide a novel therapy for colorectal cancer.

Mitotic arrest of endometrial epithelium after paclitaxel therapy for breast cancer

We report the histopathologic findings in endometrial curettings from a 31-year-old woman with dysfunctional uterine bleeding who had received paclitaxel therapy for breast carcinoma. Paclitaxel, a member of the taxane family of antineoplastic agents that is used in the treatment of breast carcinoma, ovarian carcinoma, and non-small cell lung carcinoma, acts by the simultaneous promotion of tubulin assembly into microtubules and inhibition of microtubule disassembly. The curettings in this case showed fragmented menstrual phase endometrium with striking numbers of mitotic figures. Cell divisions were arrested in metaphase. Glandular epithelial cells showed strong immunoreactivity for bcl-2 and MIB-1. We attribute this marked morphologic effect to paclitaxel-induced mitotic arrest of the endometrium.

Fibroblast growth factors are translocated to the nucleus of human endothelial cells in a microtubule- and lysosome-independent pathway

Exogenous acidic and basic fibroblast growth factors undergo rapid nuclear translocation in human umbilical vein endothelial cells. When nuclear translocation reaches saturation, more than 70% of the internalized growth factors are in the nuclear fraction. Lysosomal inhibitors, such as leupeptin and chloroquine, and microtubule inhibitors including colchicine and 2-methoxyl-beta-estradiol neither increase nor decrease nuclear translocation. The results suggest that nuclear translocation of fibroblast growth factors does not require cytosolic accumulation or lysosomal processing and that the transportation of exogenous growth factors across the cytoplasm is independent of microtubules.

Phase II and pharmacokinetic study of paclitaxel therapy for unresectable hepatocellular carcinoma patients

Hepatocellular carcinoma (HCC) is a common lethal disease in Asia and there is no effective chemotherapy. Identification of new effective drugs in the treatment of inoperable HCC is urgently need. This is a phase II clinical study to investigate the efficacy, toxicity and pharmacokinetics of paclitaxel in HCC patients. Twenty patients with measurable, unresectable HCC, normal serum bilirubin, normal bone marrow and renal functions were studied. Paclitaxel 175 mg m(-2) was given intravenously over 3 h every 3 weeks. No complete or partial responses were observed. Five patients had stable disease. Major treatment toxicities (grade 3-4) were neutropenia (25%), thrombocytopenia (15%), infection (10%) and allergy (10%). Treatment-related deaths occurred in two patients. The median survival was 12 weeks (range 1-36). Paclitaxel is metabolized by the liver and the pharmacokinetics of paclitaxel in cancer patients with liver involvement or impairment may be important clinically. Pharmacokinetic study was completed in 13 HCC patients. The paclitaxel area under the curve was significantly increased (P < 0.02), clearance decreased (P < 0.02) and treatment-related deaths increased (P = 0.03) in patients with hepatic impairment. In conclusion, paclitaxel in this dose and schedule has no significant anti-cancer effect in HCC patients. Paclitaxel should be used with caution in cancer patients with liver impairment.

Complement activation by Cremophor EL as a possible contributor to hypersensitivity to paclitaxel: an in vitro study

BACKGROUND

Cancer patients treated with the anticancer drug, paclitaxel (Taxol) often experience mild to severe hypersensitivity reactions. It is not known how these reactions are induced and whether the inducer is paclitaxel or its vehicle (i.e., Cremophor EL in 50% ethanol). Molecules present in Cremophor EL are similar in structure to certain nonionic block copolymers that activate complement proteins (i.e., proteins involved in various immune processes). To explore the role of complement in the observed hypersensitivity reactions, we studied the effects of paclitaxel and Cremophor EL plus ethanol on human complement in vitro.

METHODS

Serum specimens from healthy individuals and cancer patients were incubated with paclitaxel or with relevant control compounds (Cremophor EL with ethanol, ethanol only, docetaxel, and cyclosporine), and markers of complement activation (SC5b-9 and Bb) were measured by enzyme-linked immunosorbent assay. Similar incubations were performed in the presence of inhibitors of complement activation (i.e., EGTA/Mg2+ and soluble complement receptor type 1 [sCR1]).

RESULTS

Paclitaxel in Cremophor EL plus ethanol caused increased formation of SC5b-9 in serum specimens from 10 of 10 healthy control subjects and from five of 10 cancer patients. Experiments with one or more individual sera indicated the above effect was due to Cremophor EL plus ethanol, that increased formation of Bb also occurred, that the drug-induced rise in SC5b-9 was inhibited by sCR1, and that EGTA/Mg2+ partially inhibited SC5b-9 formation and stimulated Bb formation.

IMPLICATION

The role of complement activation in hypersensitivity reactions associated with administration of paclitaxel in Cremophor EL plus ethanol should be studied in vivo.

Microtubule stability in budding yeast: characterization and dosage suppression of a benomyl-dependent tubulin mutant

To better understand the dynamic regulation of microtubule structures in yeast, we studied a conditional-lethal beta-tubulin mutation tub2-150. This mutation is unique among the hundreds of tubulin mutations isolated in Saccharomyces cerevisiae in that it appears to cause an increase in the stability of microtubules. We report here that this allele is a mutation of threonine 238 to alanine, and that tub2-150 prevents the spindle from elongating during anaphase, suggesting a nuclear microtubule defect. To identify regulators of microtubule stability and/or anaphase, yeast genes were selected that, when overexpressed, could suppress the tub2-150 temperature-sensitive phenotype. One of these genes, JSN1, encodes a protein of 125 kDa that has limited similarity to a number of proteins of unknown function. Overexpression of the JSN1 gene in a TUB2 strain causes that strain to become more sensitive to benomyl, a microtubule-destabilizing drug. Of a representative group of microtubule mutants, only one other mutation, tub2-404, could be suppressed by JSN1 overexpression, showing that JSN1 is an allele-specific suppressor. As tub2-404 mutants are also defective for spindle elongation, this provides additional support for a role for JSN1 during anaphase.