Clinical significance of plasma anti-TOPO48 autoantibody and blood survivin-expressing circulating cancer cells in patients with early stage endometrial carcinoma.

PURPOSE: To examine the clinical significance of an autoantibody (AAb) against a novel tumor-associated antigen (TAA) derived from human DNA-topoisomerase I, termed as TOPO48 AAb, and peripheral blood survivin-expressing circulating cells (CCC) in patients with early stage endometrial cancer (EC). METHODS: Blood samples were collected from 80 patients with early stage EC and 80 age-matched healthy subjects. Plasma levels of the TOPO48 AAb were measured with a specific antibody capture enzyme-linked immunosorbent assay (ELISA) and blood survivin-expressing CCC assessed with a reverse transcription-polymerase chain reaction products based on a hybridization-enzyme-linked immunosorbent assay (RT-PCR-ELISA). Sixty patients were followed up for 36 months after the initial assay test. RESULTS: There were 75% and 60% samples with positive levels of the TOPO48 AAb and survivin-expressing CCC in the cancer patients, respectively. However, the cumulative positive rate of combination of the two markers was increased to 93.3% with 0.927 (95% CI 0.871-0.984) of area under the curve (AUC) in receiver operating characteristic (ROC) curve analysis. During the follow-up period, patients with positive TOPO48 AAb but negative surviving-expressing CCC had a higher survival rate and a longer survival time than those with negative AAb but positive CCC (P = 0.01). CONCLUSIONS: The combination of TOPO48 AAb and survivin-expressing CCC may be used as a novel recipe to improve the efficiency of early diagnosis and provide more accurate prognostic prediction in patients with early stage EC.

An Autoantibody Against Human DNA-Topoisomerase I Is a Novel Biomarker for Non-Small Cell Lung Cancer.

BACKGROUND: We previously reported a novel tumor-associated antigen with a molecular weight of approximately 48 kDa that was a fragment derived from human DNA-topoisomerase I. The aim of this study is to further investigate the clinical significance of the autoantibody in patients with non-small cell lung cancer (NSCLC). METHODS: We determined serum levels of the autoantibody in 127 NSCLC patients, 127 age-, sex-, and smoking history-matched healthy control subjects, and 38 patients with pulmonary benign tumors by using a specific enzyme linked immunosorbent assay for the autoantibody. We then statistically evaluated its clinical application value. RESULTS: Serum levels of the autoantibody in NSCLC patients were significantly higher than in healthy control subjects and patients with benign tumors (p = 0.001). The percentage of sera with a positive level of the autoantibody was 71.8%, 65.6%, 41.9%, and 48.0% in stages I, II, III, and IV of the cancer, respectively (p = 0.049). The area under the receiver-operating characteristics curve was 0.971 (95% confidence interval: 0.953 to 0988) for healthy controls and patients with benign tumors versus early stage NSCLC patients. Moreover, the overall survival rate of the patients in stages I, II, and IV with negative levels of the autoantibody was significantly lower than that of patients with positive levels of the autoantibody (p = 0.013, 0.023, and 0.047 for stages I, II, and IV, respectively). CONCLUSIONS: Our results indicate that the autoantibody can be used as a novel biomarker for the early diagnosis and prognosis of NSCLC.

Electrochemical immunosensor for detection of topoisomerase based on graphene-gold nanocomposites.

A facile electrochemical immunosensor based on graphene-three dimensional nanostructure gold nanocomposites (G-3D Au) using simple and rapid one-step electrochemical co-reduction technique was developed for sensitive detection of topoisomerase. The resultant G-3D Au nanocomposites were characterized by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy, and then were used as a substrate for construction of the "sandwich-type" immunosensor. Amperometric current-time curve was employed to monitor the immunoreaction on the protein modified electrode. The proposed method could respond to topoisomerase with a linear calibration range from 0.5 ng mL(-1) to 50 ng mL(-1) with a detection limit of 10 pg mL(-1). This new biosensor exhibited a fast amperometric response, high sensitivity and selectivity, and was successfully used in determining the topoisomerase which was added in human serum with a relative standard deviation (n=5)<5%. The immunosensor served as a significant step toward the practical application of the immunosensor in clinical diagnosis and prognosis monitor.

Diagnostic criteria of systemic sclerosis.

Systemic sclerosis (SSc) is a multisystem disease characterized by vascular abnormalities, immune system activation manifested by SSc-specific autoantibodies and disturbances in fibroblast function. The clinical manifestations are highly heterogeneous and commonly include skin thickening, Raynaud's phenomenon, digital ulcers, gastroesophageal reflux disease, interstitial lung disease and cardiac diastolic dysfunction. The diagnosis of SSc in a patient with typical end-organ disease is relatively straight-forward, but is unsatisfactory because it implies that the diagnosis is delayed until irreversible tissue damage is present. Diagnostic criteria are generally designed to facilitate the clinical process and to allow early institution of therapy to relieve symptoms and possibly prevent irreversible damage. Several attempts at defining diagnostic criteria for SSc have been made in the past. Raynaud's phenomenon, SSc-specific autoantibodies and nailfold capillary abnormalities are among the most promising items likely to be retained in a final set of diagnostic criteria. The EULAR Scleroderma Trial and Research group (EUSTAR) is currently in the process of prospectively validating a set of diagnostic criteria for the very early diagnosis of SSc and results are expected in 2015.

Assessment of T regulatory cells and expanded profiling of autoantibodies may offer novel biomarkers for the clinical management of systemic sclerosis and undifferentiated connective tissue disease.

In order to identify disease biomarkers for the clinical and therapeutic management of autoimmune diseases such as systemic sclerosis (SSc) and undifferentiated connective tissue disease (UCTD), we have explored the setting of peripheral T regulatory (T reg) cells and assessed an expanded profile of autoantibodies in patients with SSc, including either limited (lcSSc) or diffuse (dcSSc) disease, and in patients presenting with clinical signs and symptoms of UCTD. A large panel of serum antibodies directed towards nuclear, nucleolar, and cytoplasmic antigens, including well-recognized molecules as well as less frequently tested antigens, was assessed in order to determine whether different antibody profiles might be associated with distinct clinical settings. Beside the well-recognized association between lcSSc and anti-centromeric or dcSSC and anti-topoisomerase-I antibodies, we found a significative association between dcSSc and anti-SRP or anti-PL-7/12 antibodies. In addition, two distinct groups emerged on the basis of anti-RNP or anti-PM-Scl 75/100 antibody production among UCTD patients. The levels of T reg cells were significantly lower in patients with SSc as compared to patients with UCTD or to healthy controls; in patients with lcSSc, T reg cells were inversely correlated to disease duration, suggesting that their levels may represent a marker of disease progression.

Specific detection of topoisomerase I from the malaria causing P. falciparum parasite using isothermal rolling circle amplification.

We present a Rolling-Circle-Enhance-Enzyme-Activity-Detection (REEAD) system with potential use for future point-of-care diagnosis of malaria. In the developed setup, specific detection of malaria parasites in crude blood samples is facilitated by the conversion of single Plasmodium falciparum topoisomerase I (pfTopI) mediated cleavage-ligation events, happening within nanometer dimensions, to micrometer-sized products readily detectable at the single molecule level in a fluorescence microscope. In principle, REEAD requires no special equipment and the readout is adaptable to simple colorimetric detection systems. Moreover, with regard to detection limit the presented setup is likely to outcompete standard gold immuno-based diagnostics. Hence, we believe the presented assay forms the basis for a new generation of easy-to-use diagnostic tools suitable for the malaria epidemic areas in developing countries.

Development and validation of an immunoassay for quantification of topoisomerase I in solid tumor tissues.

BACKGROUND: Topoisomerase I (Top1) is a proven target for cancer therapeutics. Recent data from the Fluorouracil, Oxaliplatin, CPT-11: Use and Sequencing (FOCUS) trial demonstrated that nuclear staining of Top1 correlates with chemotherapeutic efficacy. Such a correlation may help identify patients likely to respond to Top1 inhibitors and illuminate their mechanism of action. Cellular response to Top1 inhibitors is complex, but Top1 target engagement is a necessary first step in this process. This paper reports the development and validation of a quantitative immunoassay for Top1 in tumors. METHODOLOGY/PRINCIPAL FINDINGS: We have developed and validated a two-site enzyme chemiluminescent immunoassay for quantifying Top1 levels in tumor biopsies. Analytical validation of the assay established the inter-day coefficient of variation at 9.3%±3.4% and a 96.5%±7.3% assay accuracy. Preclinical fit-for-purpose modeling of topotecan time- and dose-effects was performed using topotecan-responsive and -nonresponsive xenografts in athymic nude mice. Higher baseline levels of Top1 were observed in topotecan-responsive than -nonresponsive tumors. Top1 levels reached a maximal decrease 4 to 7 hours following treatment of engrafted mice with topotecan and the indenoisoquinoline NSC 724998. CONCLUSIONS/SIGNIFICANCE: Our analysis of Top1 levels in control and treated tumors supports the previously proposed mechanism of action for Top1 inhibitor efficacy, wherein higher baseline Top1 levels lead to formation of more covalent-complex-dependent double-strand break damage and, ultimately, cell death. In contrast, xenografts with lower baseline Top1 levels accumulate fewer double-stand breaks, and may be more resistant to Top1 inhibitors. Our results support further investigation into the use of Top1 levels in tumors as a potential predictive biomarker. The Top1 immunoassay described in this paper has been incorporated into a Phase I clinical trial at the National Cancer Institute to assess pharmacodynamic response in tumor biopsies and determine whether baseline Top1 levels are predictive of response to indenoisoquinoline Top1 inhibitors.

Phase I Study of Topotecan, Ifosfamide, and Etoposide (TIME) with autologous stem cell transplant in refractory cancer: pharmacokinetic and pharmacodynamic correlates.

PURPOSE: To determine the maximum tolerated dose (MTD) of topotecan in combination with ifosfamide, mesna, and etoposide (TIME), followed by autologous hematopoietic cell transplant (HCT), in patients with chemotherapy-refractory malignancies. EXPERIMENTAL DESIGN: Patients were treated with (in mg/m(2)/d) ifosfamide 3,333, mesna 3,333, and topotecan 3.3 to 28.3 during days -8 through -6 and etoposide 500 (days -5 through -3) followed by HCT on day 0. Once MTD was defined, we expanded this dosing cohort to include patients with high-risk lymphoma due to activity seen during dose escalation. Topotecan pharmacokinetic analyses were carried out, and topoisomerase I levels and activity were measured. RESULTS: The topotecan MTD in this regimen was 64 mg/m(2) (21.3 mg/m(2)/d). Mucositis was dose limiting and correlated with topotecan dose level and area under the curve (AUC). Dose level was also correlated with length of hospitalization, number of days of parenteral nutrition, and neutrophil and platelet engraftment. Topotecan AUC was significantly correlated with time to platelet recovery. The baseline peripheral blood mononuclear cell topoisomerase I level was found to be a significant positive predictor for overall and progression-free survival. Topotecan AUC was positively correlated with dose level, with a trend toward decreasing clearance with increasing dose. CONCLUSION: Topotecan can be a useful drug in the high-dose setting given its activity in some malignancies when given in standard dose. Pharmacokinetic monitoring may be a valuable tool for optimizing the use of topotecan and to avoid toxicity seen with high-systemic exposures. Baseline topoisomerase I levels may have an important role in predicting topotecan efficacy.

An improved method for large-scale preparation of negatively and positively supercoiled plasmid DNA.

A rigorous understanding of the biological function of superhelical tension in cellular DNA requires the development of new tools and model systems for study. To this end, an ethidium bromide[#x02013]free method has been developed to prepare large quantities of either negatively or positively super-coiled plasmid DNA. The method is based upon the known effects of ionic strength on the direction of binding of DNA to an archaeal histone, rHMfB, with low and high salt concentrations leading to positive and negative DNA supercoiling, respectively. In addition to fully optimized conditions for large-scale (>500 microg) supercoiling reactions, the method is advantageous in that it avoids the use of mutagenic ethidium bromide, is applicable to chemically modified plasmid DNA substrates, and produces both positively and negatively supercoiled DNA using a single set of reagents.

Induction of interferon-alpha by scleroderma sera containing autoantibodies to topoisomerase I: association of higher interferon-alpha activity with lung fibrosis.

OBJECTIVE: Peripheral blood cells (PBMCs) from some patients with systemic sclerosis (SSc) express an interferon-alpha (IFNalpha) signature. The aim of this study was to determine whether SSc patient sera could induce IFNalpha and whether IFNalpha induction was associated with specific autoantibodies and/or clinical features of the disease. METHODS: SSc sera containing autoantibodies against either topoisomerase I (anti-topo I; n = 12), nucleolar protein (ANoA; n = 12), or centromeric protein (ACA; n = 13) were cultured with a HeLa nuclear extract and normal PBMCs. In some experiments, different cell extracts or inhibitors of plasmacytoid dendritic cell (DC) activation, Fcgamma receptor II (FcgammaRII), endocytosis, or nucleases were used. IFNalpha was measured by enzyme-linked immunosorbent assay. RESULTS: Topo I-containing sera induced significantly higher levels of IFNalpha as compared with all other groups. IFNalpha induction was inhibited by anti-blood dendritic cell antigen 2 (90%), anti-CD32 (76%), bafilomycin (99%), and RNase (82%). In contrast, ACAs induced low levels of IFNalpha even when necrotic, apoptotic, or demethylated extracts were used, despite the fact that CENP-B-binding oligonucleotide containing 2 CpG motifs effectively stimulated IFNalpha. IFNalpha production was significantly higher in patients with diffuse SSc (mean +/- SEM 641 +/- 174 pg/ml) than in those with limited SSc (215 +/- 66 pg/ml) as well as in patients with lung fibrosis than in those without. CONCLUSION: Autoantibody subsets in SSc sera differentially induce IFNalpha and may explain the IFNalpha signature observed in SSc. IFNalpha is induced by plasmacytoid DCs and required uptake of immune complexes through FcgammaRII, endosomal transport, and the presence of RNA, presumably for interaction with Toll-like receptor 7. The higher IFNalpha induction in sera from patients with diffuse SSc than in those with limited SSc as well as in sera from patients with lung fibrosis suggests that IFNalpha may contribute to tissue injury.

Phase I dose escalation study with irinotecan, capecitabine, epirubicin, and granulocyte colony-stimulating factor support for patients with solid malignancies.

OBJECTIVES: Preclinical studies using sequences of topoisomerase I and II inhibitors suggested synergism; preliminary clinical studies, resulting in enhanced antitumor responses, confirm this in selected malignancies. This study determined the maximum-tolerated dose (MTD), toxicity, and pharmacokinetics of irinotecan (CPT-11), capecitabine, and epirubicin in patients with metastatic adenocarcinoma of lung, breast, or gastrointestinal tract. Correlation of topoisomerase IIbeta was also done. METHODS: Eligibility criteria included the following: documented adenocarcinoma of the lung, breast, or gastrointestinal tract, <3 prior chemotherapy regimens, Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2, age > or =18 years, adequate organ function, and signed informed consent. Irinotecan was administered at 250 mg/m2 intravenously day 1 every 21-day cycle, but was reduced to 180 mg/m2 in cohort 2 due to toxicity. Capecitabine was administered at 750 mg/m2 twice daily days 2 to 14 in cohort 1 but only on days 2 to 7 from cohort 2 due to early neutropenia and to allow for prophylactic granulocyte colony-stimulating factor (GCSF) support. Epirubicin was administered at 40 mg/m2 in cohort 1, but reduced to 30 mg/m2 in cohort 2, then reescalated until the MTD was reached. RESULTS: Toxicity was assessed in 21 patients; response was assessed in 17 patients. The most common grade 3 to 4 toxicities included neutropenia (57.1%) and anemia (28.6%). The MTD of epirubicin was 50 mg/m2. In evaluable patients, there were 2 partial responses (11.8%) and 13 stable disease (76.5%); these correlated well with topoisomerase IIbeta. CONCLUSIONS: The recommended doses for phase II studies: irinotecan 180 mg/m2 day 1, epirubicin 50 mg/m2 day 2, and capecitabine 750 mg/m2 twice daily days 2 to 7 of each 21-day cycle. This combination is reasonably active and warrants evaluation in the phase II setting.

Phase II study of sequentially administered low-dose mitomycin-C (MMC) and irinotecan (CPT-11) in women with metastatic breast cancer (MBC).

BACKGROUND: Preclinical studies show that mitomycin-C (MMC) followed by irinotecan (CPT-11) is synergistic. Therefore, we evaluated the toxicity and efficacy of sequentially administered low-dose MMC and CPT-11 in patients (pts) with pretreated metastatic breast cancer (MBC). Secondary objective was to evaluate the correlation between MMC-induced topoisomerase I (TOPO I) expression and NAD(P)H:quinone oxireductase 1 (NQO1) genotypes in peripheral blood mononuclear cells (PBMC) and efficacy or toxicity of the regimen. DESIGN: Thirty-two pts received MMC i.v. 6 mg/m(2) day 1 and CPT-11 i.v. 125 mg/m(2) days 2 and 8 every 28 days for maximum of six cycles. TOPO I expression and NQO1 reductase genotyping in 23 of 32 (72%) pts were assayed by PCR. RESULTS: The median time to progression (TTP) was 4.7 months (95% confidence interval 4.0-5.4 months). TOPO I expression was increased 5- to 10-fold and 20- to 30-fold in PBMC at 24 and 168 h, respectively. There was no relationship between these markers and efficacy or toxicity of the regimen. CONCLUSIONS: Sequential low-dose MMC and CPT-11 was active and tolerable by pretreated MBC pts. Future trials should focus on less pretreated MBC pts and sequential tumor biopsies to test the hypothesis that increased intratumoral expression of TOPO I is related to efficacy.

Pathogenic autoantibodies in systemic sclerosis.

Systemic sclerosis, scleroderma, is a disease characterized by widespread vascular injury and fibrosis of the skin and visceral organs. Circulating autoantibodies against several intracellular antigens are common in scleroderma patients. The specificities of such autoantibodies correlate with distinct clinical manifestations. However, till date there is no evidence that these autoantibodies, though helpful in diagnosis and prognosis, are linked to the pathogenesis of scleroderma nor that they may cause any feature of the disease. Recently, the discovery of novel agonistic autoantibodies targeting the PDGF receptor has provided important insight into the molecular pathogenesis of scleroderma and the intracellular mechanisms leading to fibrosis. Although their pathogenic role awaits validation in in vivo models, these antibodies represent the molecular link between the immune system and fibrosis.

Sequential oral 9-nitrocamptothecin and etoposide: a pharmacodynamic- and pharmacokinetic-based phase I trial.

PURPOSE: Resistance to topoisomerase (topo) I inhibitors has been related to down-regulation of nuclear target enzyme, whereas sensitization to topo II inhibitors may result from induction of topo II by topo I inhibitors. Here, we evaluated a sequence-specific administration of a topo I inhibitor followed by a topo II inhibitor. EXPERIMENTAL DESIGN: Twenty-five patients with advanced or metastatic malignancies were treated with increasing doses (0.75, 1.0, 1.25, 1.5, 1.75, or 2.0 mg/m(2)) of 9-nitrocamptothecin (9-NC) on days 1 to 3, followed by etoposide (100 or 150 mg/d) on days 4 and 5. At the maximally tolerated dose, 20 additional patients were enrolled. The median age was 60 years (range, 40-84 years). Endpoints included pharmacokinetic analyses of 9-NC and etoposide, and treatment-induced modulations of topo I and II expression in peripheral blood mononuclear cells. RESULTS: Neutropenia, thrombocytopenia, nausea, vomiting, diarrhea, and fatigue were dose-limiting toxicities and occurred in six patients. Despite a median number of four prior regimens (range 1-12), 2 (4%) patients had an objective response and 13 (29%) patients had stable disease. In contrast to the expected modulation in topo I and IIalpha levels, we observed a decrease in topo IIalpha levels, whereas topo I levels were not significantly altered by 9-NC treatment. CONCLUSIONS: Sequence-specific administration of 9-NC and etoposide is tolerable and active. However, peripheral blood mononuclear cells may not be a predictive biological surrogate for drug-induced modulation of topo levels in tumor tissues and should be further explored in larger studies.

Evaluation of topoisomerase-1-specific CD8+ T-cell response in systemic sclerosis.

Measurement of disease activity in systemic autoimmune disorders is often unreliable, and immunosuppressive therapy is often titrated to crude clinical response and/or onset of complications. Systemic sclerosis (SSc) presents a distinct clinical phenotype associated with specific autoantibodies. Anti-topoisomerase-1 (SCL-70) is selectively detected in 30-60% of subjects with diffuse skin and interstitial lung involvement. Such patients offer an ideal clinical model to characterize and quantify the autoantigen-specific T-cell response and its correlation with disease phenotype and activity. Human leukocyte antigen A2 (HLA-A2)-restricted topo-1 peptides were selected based on an epitope prediction algorithm. For initial studies, the best binder topo-1(262-270) KMLDHEYTT (#262) was used alone or loaded onto an artificial antigen-presenting platform generated by coupling a dimeric major histocompatibility complex-immunoglobulin G fusion protein (HLA-A2-Ig) and anti-CD28 antibodies onto magnetic beads (artificial antigen-presenting cells). Blood samples (100 microL) from HLA-A2+ SSc patients and cytomegalovirus (CMV) seropositive healthy control subjects were tested in an intracellular cytokine staining assay. Gamma interferon production by CD8+ T cells was measured after stimulation with peptide #262, CMVpp65, or MART-1 (irrelevant peptide). In two of five SCL-70+ patients, peptide #262-loaded aAPCs induced a specific CD8+ T-cell response (0.45% +/- 0.23% of total CD8+ cells). This response was not observed in the seven SCL-70- (five SSc and two CMV+) control subjects studied (0.03% +/- 0.02%). Interestingly, bronchoalveolar lavage fluid obtained from one topo-1-responsive SSc patient who had worsening respiratory function and active alveolitis showed striking enrichment of topo-1-specific CD8+ T cells (3.94%). This small-volume ex vivo assay may prove to be a sensitive and specific tool to assess disease activity and to monitor response to therapy in patients with scleroderma.

A phase I study of sequential administration of escalating doses of intravenous paclitaxel, oral topotecan, and fixed-dose oral etoposide in patients with solid tumors.

BACKGROUND: Based on preclinical findings and on the clinical antitumor efficacy of sequential paclitaxel/topotecan and topotecan/etoposide, the authors sought to define the maximum tolerated doses (MTDs) and dose-limiting toxicities (DLTs) associated with a sequential combination of paclitaxel, topotecan, and etoposide in patients with solid tumors. METHODS: The MTDs were determined through standard dose escalation in cohorts of three patients. Patients with refractory solid tumors and performance status < or = 2 were treated with intravenous paclitaxel 50-110 mg/m(2) (Day 1), oral topotecan 0.5-2.0 mg/m(2) (Days 2-4), and oral etoposide 160 mg/m(2) (Days 5-7) during every 21-day cycle. For dose-limiting neutropenia, granulocyte-colony-stimulating factor (G-CSF) was administered on Day 8 in subsequent cohorts. Blood samples were obtained before treatment during Cycle 1 (Days 1, 2, and 5) for topoisomerase I assessment. RESULTS: Twenty-eight patients received a combined total of 129 cycles. The MTDs were paclitaxel 80 mg/m(2), topotecan 1.5 mg/m(2), and etoposide 160 mg/m(2) without G-CSF. In minimally pretreated patients, G-CSF allowed paclitaxel dose escalation to 110 mg/m(2). Three patients (11%) had radiologic partial responses, and 4 patients (14%) had stable disease. Day 2 topoisomerase I levels increased by 2-15 times relative to baseline levels in 7 of 14 patients analyzed (50%). CONCLUSIONS: The novel sequential combination that was evaluated generally was well tolerated and active in patients with refractory solid tumors. Based on hematologic DLTs, the authors recommend further evaluation of paclitaxel 110 mg/m(2), topotecan 1.5 mg/m(2), and etoposide 160 mg/m(2) with G-CSF support in minimally pretreated patients.

Phase I evaluation of sequential topoisomerase targeting with irinotecan/cisplatin followed by etoposide in patients with advanced malignancy.

PURPOSE: To investigate pharmacologically guided addition of etoposide to a weekly irinotecan/cisplatin chemotherapy. PATIENTS AND METHODS: Patients with advanced nonhematologic malignancies were eligible. Treatment consisted of i.v. administration of 50 mg/m(2) irinotecan and 20 mg/m(2) cisplatin on days 1, 8, 15, and 22 of a 42-day cycle or on days 1 and 8 of a 21-day cycle. Etoposide was administered in a dose-escalating fashion 2 days after each dose of irinotecan/cisplatin, either i.v. as a single dose or p.o. as two doses administered 12 h apart. Pharmacologic analyses included measurement of plasma concentrations of irinotecan, SN-38, and SN-38 glucuronide, as well as quantitation of topoisomerase protein levels in peripheral blood mononuclear cells (PBMNCs). RESULTS: A total of 40 patients with a variety of malignancies received 122 cycles of therapy. Dose-limiting toxicities included neutropenia and diarrhea, with the 21-day cycle tolerated better than the 42-day cycle. For the 21-day cycle, the maximum tolerated dose was 75 mg/m(2) for i.v. etoposide and 85 mg/m(2) for oral etoposide. Objective responses were observed in four patients with previously treated mesothelioma, gastric, breast, and ovarian cancer, respectively. PBMNC levels of topoisomerase IIalpha were increased at the time of etoposide administration in two patients, with these patients having the highest SN-38 glucuronide peak-plasma-concentration and area-under-the-curve values among 15 patients with available pharmacokinetic data. One of these patients had a partial response to therapy. CONCLUSIONS: Pharmacologically guided administration of etoposide in combination with irinotecan/cisplatin using a 21-day cycle is associated with acceptable toxicity and significant antitumor activity. The finding that PBMNC topoisomerase IIalpha protein levels increased after irinotecan/cisplatin treatment in two of six patients supports the continued development of sequential topoisomerase targeting in the treatment of malignancy.

Autoantigen components recognizable by scleroderma sera are exported via ectocytosis of fibroblasts.

Previously, we have demonstrated that ectocytosis, a unique cell trafficking process to export a specific subset of cellular proteins in the form of membrane vesicles, can be triggered from human skin fibroblasts cultured in a three-dimensional collagen lattice upon stress relaxation. The same culturing system was employed in the present study using fibroblasts isolated from patients with systemic sclerosis (SSc). To see whether any putative intracellular autoantigens causing SSc might escape out of cells by way of ectocytosis, the same stress-relaxation method was used to induce a synchronized ectocytosis among cultured cells. Membrane vesicles released by scleroderma fibroblasts were subsequently isolated, resolved on SDS-PAGE and immunoblotted with sera from 89 patients with various autoimmune diseases and 11 normal volunteers. Three major polypeptides with apparent mol. wts of 12-14, 32-34 and 70-80 kDa are prominent bands on both SDS-PAGE and immunoblots. The 32-34 kDa polypeptide has been further identified as a member of the annexin protein family, while the 70-80 kDa protein has been shown to be topoisomerase I, as judged by its reactivity to patients' sera and a rabbit polyclonal antibody, and as also judged by a functional assay. In conclusion, our results suggest that ectocytosis might be one of the potential pathways for cells to export intracellular antigens and subsequently cause autoimmune reactions.

Effect of prolonged topotecan infusion on topoisomerase 1 levels: a phase I and pharmacodynamic study.

Topoisomerase 1 (topo-1) inhibitors act on the target enzyme by forming "cleavable complex," a high molecular weight DNA protein adduct. The formation of such cleavable complexes results in depletion of the Mr 100,000 "free" topo-1 band detectable by Western blot. The objectives of this study were to determine the maximally tolerated dose of prolonged topotecan infusion in previously untreated and minimally pretreated patients. A secondary objective was to measure the effect of prolonged topotecan infusion on topo-1 levels in peripheral blood mononuclear cells (PBMCs) as a pharmacodynamic end point. In a prior Phase I study of 21-day topotecan infusion (H. Hochster et al., J. Clin. Oncol., 12: 553-559, 1994), the maximum tolerated dose for patients treated previously was 0.53 mg/m2/day for 21 days every 28 days. In this study, patients with no prior therapy were treated similarly at 0.7 mg/m2/day for 21 days, and doses were escalated in 0.1 mg/m2/day increments. Patients who had one prior chemotherapy regimen or radiation therapy to a portal of