Paclitaxel and vinorelbine cause synergistic increases in apoptosis but not in microtubular disruption in human lung adenocarcinoma cells (A-549)

Liposomes for Cancer Theranostics

Cancer is one of the most well-studied diseases and there have been significant advancements over the last few decades in understanding its molecular and cellular mechanisms. Although the current treatments (e.g., chemotherapy, radiotherapy, gene therapy and immunotherapy) have provided complete cancer remission for many patients, cancer still remains one of the most common causes of death in the world. The main reasons for the poor response rates for different cancers include the lack of drug specificity, drug resistance and toxic side effects (i.e., in healthy tissues). For addressing the limitations of conventional cancer treatments, nanotechnology has shown to be an important field for constructing different nanoparticles for destroying cancer cells. Due to their size (i.e., less than 1 μm), nanoparticles can deliver significant amounts of cancer drugs to tumors and are able to carry moieties (e.g., folate, peptides) for targeting specific types of cancer cells (i.e., through receptor-mediated endocytosis). Liposomes, composed of phospholipids and an interior aqueous core, can be used as specialized delivery vehicles as they can load different types of cancer therapy agents (e.g., drugs, photosensitizers, genetic material). In addition, the ability to load imaging agents (e.g., fluorophores, radioisotopes, MRI contrast media) enable these nanoparticles to be used for monitoring the progress of treatment. This review examines a wide variety of different liposomes for cancer theranostics, with the different available treatments (e.g., photothermal, photodynamic) and imaging modalities discussed for different cancers.

Nanomechanics in Monitoring the Effectiveness of Drugs Targeting the Cancer Cell Cytoskeleton

Increasing attention is devoted to the use of nanomechanics as a marker of various pathologies. Atomic force microscopy (AFM) is one of the techniques that could be applied to quantify the nanomechanical properties of living cells with a high spatial resolution. Thus, AFM offers the possibility to trace changes in the reorganization of the cytoskeleton in living cells. Impairments in the structure, organization, and functioning of two main cytoskeletal components, namely, actin filaments and microtubules, cause severe effects, leading to cell death. That is why these cytoskeletal components are targets for antitumor therapy. This review intends to describe the gathered knowledge on the capability of AFM to trace the alterations in the nanomechanical properties of living cells induced by the action of antitumor drugs that could translate into their effectiveness.

Diagnostic and therapeutic evaluation of folate-targeted paclitaxel and vinorelbine encapsulating theranostic liposomes for non-small cell lung cancer

NSCLC is the most common type of lung cancer. However, non-specific contrast agents, radiopharmaceuticals, and treatment methods are insufficient in early diagnosis and eradication of all tumor tissue. Therefore, the formulation of a novel, targeted, specific theranostic agents possess critical importance. In our previous study, paclitaxel and vinorelbine encapsulating, Tc-99m radiolabeled, folate targeted, nanosized liposomes were formulated and found promising due to characterization properties, high cellular uptake, and cytotoxicity. In this study, in vivo therapeutic and diagnostic efficacy of liposomal formulations were tested by biodistribution study, evaluation of tumor growth inhibition, and histopathologic examination after in vitro assays on LLC1 cells. Both actively and passively targeted liposomal formulations exhibited high cellular uptake, and co-drug encapsulating liposomes showed a greater cytotoxicity profiles than free drug combination in LLC1 cells. By the results of biodistribution studies performed in NSCLC tumor-bearing C57BL/6 mice, the uptake of radiolabeled, actively folate targeted, co-drug encapsulating liposomal formulation was found to be higher in tumor tissue when compared to non-actively targeted one. Also, more effective treatment was achieved by using folate-targeted, co-drug encapsulating liposomal formulation when compared to free drugs combination according to changes in tumor size of mice. Furthermore, liposomal formulations showed lower toxicity compared to free drug combinations in the toxicity study considering body weight. Moreover, according to the histopathological study, folate targeted, co-drug encapsulating liposomes not only inhibited the tumor growth effectively but also restricted the lung metastasis entirely.

Phase I/II Trial of Paclitaxel and Vinorelbine in Advanced Non-Small Cell Lung Cancer

Chemotherapeutic combination regimens for advanced non-small cell lung cancer traditionally have been based on platin compounds. However, a mechanistic rationale could lead to effective non-platin combinations. Paclitaxel and vinorelbine are antimicrotubule agents with different mechanisms of action, both of which have single agent activity against non-small cell lung cancer. A Phase I/II trial of paclitaxel Day 1 and vinorelbine Days 1-3 every 21 days was, therefore, performed for patients with Stage IIIB or Stage IV non-small cell lung cancer who had not previously received chemotherapy for metastatic disease. In the Phase I investigation, up to 4 patients were treated at each dose level. The maximum tolerated dose level was found to be paclitaxel 150 mg/m2 IV Day 1 and vinorelbine 16 mg/m2 IV Days 1-3, with dose-limiting toxicities of fatigue, myalgia, and mucositis at higher doses. This dose level was then expanded with an additional 15 patients. Of the 23 patients treated for up to 10 cycles at or near the maximum tolerated dose level (19 patients with paclitaxel 150 mg/m2 IV Day 1 and vinorelbine 16 mg/m2 Days 1-3, and 4 patients with paclitaxel 150 mg/m2 IV Day 1 and vinorelbine 13 mg/m2 Days 1-3), 7 patients achieved partial response and 5 patients achieved minor response. Fatigue, myalgia, peripheral neuropathy, and transient leukopenia were the most common cumulative toxicities seen. The non-platin chemotherapy doublet of paclitaxel and vinorelbine given on this convenient 3-day schedule is worthy of further investigation in the treatment of non-small cell lung cancer.

Intracellular proadrenomedullin-derived peptides decorate the microtubules and contribute to cytoskeleton function

Adrenomedullin (AM) and proadrenomedullin N-terminal 20 peptide (PAMP) are secretory hormones, but it is not unusual to find them in intracellular compartments. Using yeast-2 hybrid technology, we found interactions between AM and several microtubule-associated proteins (MAPs), and between PAMP and tubulin. Expression of fluorescent-tagged AM and PAMP as well as immunofluorescence for the native peptides showed a complete decoration of the microtubules and colocalization with other MAPs. PAMP, but not AM, bound to tubulin in vitro and destabilized tubulin polymerization. Down-regulation of the gene coding for both AM and PAMP through small interfering RNA technology resulted in morphological changes, microtubule stabilization, increase in posttranslational modifications of tubulin such as acetylation and detyrosination, reduction in cell motility, and partial arrest at the G2 phase of the cell cycle, when compared with cells transfected with the same vector carrying a scrambled sequence. These results show that PAMP is a novel MAP, whereas AM may be exerting more subtle effects in regulating cytoskeleton function.

Effect of antisense RNA targeting Polo-like kinase 1 on cell growth in A549 lung cancer cells

In order to investigate the effect of Polo-like kinase-1 (Plk1) depletion on cell cycle progression and cell growth in lung cancer cells, a recombinant plasmid containing antisense RNA targeting Plk1 (pcDNA3-Plk1) was transfected into A549 cells by lipofectine. RT-PCR and Western-blot were used to detect the Plk1 gene expression. Cell proliferation was evaluated by direct cell counting and bromodeoxyuridine (BrdU) labeling. Cell cycle distribution and apoptosis were examined by flow cytometry, and the inhibition rate (IR) by vinorebline (NVB) was determined by MTT assay. The results showed that after transfection of pcDNA3-Plk1 into A549 cells, the expression levels of Plk1 mRNA and protein were greatly decreased. In pcDNA3-Plk1 transfected groups, abnormal morphological changes of cells and growth inhibition were observed, and the BrdU labeling index was significantly lower than in the control groups (P<0.05). Cells in pcDNA3-Plk1 transfected groups were arresed in G2/M phase and apoptosis was detectable 72 h post transfection. IR induced by vinorebline in pcDNA3-Plk1 transfected groups was significantly higher than in other groups. These data suggested that antisense RNA targeting Plk1 could suppress the Plk1 expression, and therefore, significantly inhibit cell proliferation and induce cell cycle arrest and apoptosis. Moreover, it sensitized lung cancer cells to chemotherapy.

Morphological and cytochemical determination of cell death by apoptosis

Several modes of cell death are now recognized, including necrosis, apoptosis, and autophagy. Oftentimes the distinctions between these various modes may not be apparent, although the precise mode may be physiologically important. Accordingly, it is often desirable to be able to classify the mode of cell death. Apoptosis was originally defined by structural alterations in cells observable by transmitted light and electron microscopy. Today, a wide variety of imaging and cytochemical techniques are available for the investigation of apoptosis. This review will highlight many of these methods, and provide a critique on the advantages and disadvantages associated with them for the specific identification of apoptotic cells in culture and tissues.

[Oral vinorelbine: pharmacology and treatment outcome in non-small cell bronchial carcinoma and breast carcinoma]

The development of an oral formulation of vinorelbine (Navelbine softgelatine capsules, Pierre Fabre Pharma, Freiburg i.Br., Germany) represents a significant advance in the treatment of patients with cancer. Oral chemotherapy is more convenient for the patients and brings significant time savings. Vinorelbine is rapidly absorbed after oral ingestion. The bioavailability is in the range of 33 to 43% and is not affected by concomitant food intake or by vomiting occuring 1.5 h or later after dosing. No significant differences in the pharmacokinetics of oral vinorelbine were observed between elderly (> or =70 years) and younger patients. The recommended dose schedule for oral vinorelbine is 60 mg/m(2) weekly for the initial 3 weeks (cycle 1) and 80 mg/m(2) weekly thereafter. However, if severe neutropenia is encountered during the first cycle, treatment is continued with weekly doses of 60 mg/m(2). Bioavailability studies have demonstrated that oral vinorelbine doses of 60 and 80 mg/m(2) are comparable to intravenous doses of 25 and 30 mg/m(2), respectively. Several clinical studies have demonstrated that the new oral formulation of vinorelbine can be safely administered, even to elderly patients, and is comparable in activity to intravenous vinorelbine in advanced non-small cell lung cancer (NSCLC) and metastatic breast cancer (MBC). A randomized phase II comparison of oral vinorelbine at the recommended dose schedule vs. intravenous vinorelbine at 30 mg/(2) in patients with advanced NSCLC found no significant differences in response rate, progression-free and overall survival between the two treatments. In studies of combination chemotherapy using vinorelbine plus cisplatin or carboplatin in advanced NSCLC, or vinorelbine plus taxanes, capecitabine,epirubicin, or the monoclonal HER2/neu antibody trastuzumab in MBC, intravenous vinorelbine could be completely or partially replaced by oral vinorelbine, resulting in maintained efficacy, good tolerability and improved patient convenience. Concurrent chemoradiation with oral vinorelbine and cisplatin was shown to be well tolerated and produced significant down-staging in patients with locally advanced NSCLC. Metronomic chemotherapy is a new treatment approach designed to maximize the antiangiogenic effect. Oral vinorelbine given every other day at low doses is currently evaluated in patients with refractory solid tumors. Oral vinorelbine has also proven useful as a substitute for intravenous vinorelbine in patients experiencing intractable acute tumor pain during or after intravenous infusion of vinorelbine.

Recent progress in histochemistry and cell biology: the state of the art 2005

Advances in the field of histochemistry, a multidisciplinary area including the detection, localization and functional characterization of molecules in single cells and complex tissues, often drives the attainment of new knowledge in the broadly defined discipline of cell biology. These two disciplines, histochemistry and cell biology, have been joined in this journal to facilitate the flow of information with celerity from technical advancement in histochemical procedures, to their utilization in experimental models. This review summarizes advancements in these fields during the past year.

Drug-eluting stents: Sirolimus and paclitaxel differentially affect cultured cells and injured arteries

Sirolimus and paclitaxel eluted from stents inhibit cell proliferation and other cellular processes by dramatically different mechanisms. In this study, the effects of sirolimus and paclitaxel on cultured human coronary artery smooth muscle and endothelial cell function or cell cycle changes in balloon-injured arteries were directly compared. Both sirolimus and paclitaxel inhibited smooth muscle and endothelial cell proliferation. However, only paclitaxel inhibited smooth muscle and endothelial cell migration at low (nM) concentrations. Sirolimus arrested smooth muscle and endothelial cells in the G0/G1 phase of the cell cycle without inducing apoptosis while paclitaxel produced apoptosis in both cell types at low nanomolar concentrations. Although both agents blocked neointimal formation, sirolimus applied locally to injured rat carotid arteries increased the percentage of cycling vascular cells in G0/G1 without inducing apoptosis while paclitaxel increased the percentage of cycling cells in S and G2/M phases while inducing apoptosis. These results suggest that sirolimus reduces neointimal hyperplasia through a cytostatic mechanism while paclitaxel produces apoptotic cell death.

News and views in Histochemistry and Cell Biology

Advances in histochemical methodology and ingenious applications of novel and improved methods continue to confirm the standing of morphological means and approaches in research efforts, and contribute significantly to increasing our knowledge about structures and functions in all areas of the life sciences from cell biology to pathology. Reports published during recent months documenting this progress are summarized in the present review.