Results of phase I pharmacokinetic and pharmacodynamic studies of the Raf kinase inhibitor BAY 43-9006 in patients with solid tumors.
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Publications and source records attributed to S Seeber.
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PURPOSE: We investigated whether increasing the patients' processed blood volume (BV) during peripheral blood stem cell collection (PBSCC) from four to five times leads to a greater yield of CD34+ cells. We also studied the kinetics of CD34+38- and CD34+49d+ subsets and compared the amount of transfused cells with engraftment. METHODS: All patients ( n=20) received chemotherapy followed by G-CSF for PBSC mobilization. Samples from the patients' peripheral blood and the PBSC harvests were taken after processing 1-, 4-, and 5 times the patients' calculated BV. RESULTS: The mean total yields of CD34+, CD34+38-, and CD34+49d+ cells were 15.69-, 1.13- and 4.17 x 10(6)/kg body weight, respectively. The mean increase for these subsets between 4- and 5 BV was 10%, 8%, and 21%, respectively. Based on the mean number of 2.25 (range 2-3) planned courses of high-dose chemotherapy (HDC) per patient, the mean yield of CD34+ cells per kg body weight and intended course of HDC after 4- and 5 BV was 6.31- and 6.97 x 10(6) ( P=0.014). Twenty HDC were evaluable for engraftment. There was some correlation between the number of transfused CD34+ and CD34+38- cells and WBC engraftment ( r = -0.66 and --0.69; P<0.01) and CD34+ cells and platelet engraftment ( r = -0.56; P= 0.013). No toxicity occurred during PBSCC, although the mean platelet count dropped by 50% which must be kept in mind regarding the additional application of anti-coagulants and the fact that most patients had large indwelling catheters. CONCLUSION: Processing 4 BV is sufficient to collect >5 x 10(6) CD34+ cells/kg body weight and intended course of HDC in most patients, although extension to 5 BV further increases the total yield of CD34+ cells.
The goal of this study was to establish a two-plasmid co-expression system for Mycobacterium smegmatis. Two vectors with compatible origins of replication and a polylinker, which allows modular cloning of promoters and genes, were constructed and used to clone genes encoding a blue fluorescent protein (BFP) and a green fluorescent protein (GFP). A 160-fold variation of GFP expression levels in M. smegmatis was achieved by combining three promoters with different copy numbers of the vectors. An efficient energy transfer between BFP and GFP in M. smegmatis was observed by fluorescence measurements and demonstrated that these genes were simultaneously expressed from both vectors. Thus, these vectors will be valuable for all strategies where co-expression of proteins in M. smegmatis is needed, e.g. for constructing a two-hybrid system or for deleting essential genes.
PURPOSE AND METHODS: For more than three decades, the therapeutic options for patients with advanced colorectal cancer have almost exclusively been based on fluoropyrimidines. With the recognition that topoisomerase-I (TOP-I) is an important therapeutic target in cancer therapy, irinotecan, a semisynthetic TOP-I-interactive camptothecin derivative, has been clinically established in the treatment of colorectal cancer. RESULTS: Irinotecan was investigated as second-line chemotherapy after prior treatment with fluorouracil (FU)-based regimens in two large randomized phase III trials comparing irinotecan with either best supportive care or an infusional FU/leucovorin (LV) regimen. The outcomes of these trials established irinotecan as the standard therapy in the second-line treatment of colorectal cancer. The therapeutic value of irinotecan in the first-line treatment of metastatic colorectal cancer was investigated in two large randomized phase III trials comparing the combination of irinotecan and FU/LV with FU/LV alone. Both trials demonstrated significant superior efficacy for the combination of irinotecan and FU/LV in terms of response rate, median time to disease progression, and median survival time. Consequently, the combination of irinotecan and FU/LV has been approved as first-line chemotherapy for patients with metastatic colorectal cancer and constitutes the reference therapy against which other treatment options must be tested in the future. CONCLUSION: In this review, the clinical rationale and update of the present clinical status of irinotecan in the treatment of colorectal cancer and future prospects of irinotecan-based combinations are discussed.
N-(pyridin-4-yl)-[1-(4-chlorbenzyl)-indol-3-yl]-glyoxyl-amid (D-24851) is a novel synthetic compound that was identified in a cell-based screening assay to discover cytotoxic drugs. D-24851 destabilizes microtubules and blocks cell cycle transition specifically at G2-M phase. The binding site of D-24851 does not overlap with the tubulin binding sites of known microtubule-destabilizing agents like vincristine or colchicine. In vitro, D-24851 has potent cytotoxic activity toward a panel of established human tumor cell lines including SKOV3 ovarian cancer, U87 glioblastoma, and ASPC-1 pancreatic cancer cells. In vivo, oral D-24851 treatment induced complete tumor regressions (cures) in rats bearing Yoshida AH13 sarcomas. Of importance is that the administration of curative doses of D-24851 to the animals revealed no systemic toxicity in terms of body weight loss and neurotoxicity in contrast to the administration of paclitaxel or vincristine. Interestingly, multidrug-resistant cell lines generated by vincristine-driven selection or transfection with the Mr 170,000 P-glycoprotein encoding cDNA were rendered resistant toward paclitaxel, vincristine, or doxorubicin but not towards D-24851 when compared with the parental cells. Because of its synthetic nature, its oral applicability, its potent in vitro and in vivo antitumoral activity, its efficacy against multidrug-resistant tumors, and the lack of neurotoxicity, D-24851 may have significant potential for the treatment of various malignancies.
PURPOSE: We report the results of high-dose chemotherapy (HDC) with peripheral blood stem cell transplantation in twenty-one patients with primarily advanced or relapsed ovarian cancer. METHODS: Twenty-five women underwent stem cell collection, and 21 were finally treated with different regimens of HDC containing cyclophosphamide, etoposide, carboplatin, and treosulfan. The patients received cyclophosphamide +/- cisplatin and cisplatin + paclitaxel, respectively, followed by G-CSF (n = 24) or GM-CSF (n = 1) for stem cell mobilization. RESULTS: A mean of 7.2 +/- 6.1 x 10(6) CD34+ cells per kg bw were collected. Thirteen patients received double transplants and one patient received a triple transplant. The median age was 47 years (range 24-61 years) and the mean number of prior regimens was three (range 1-8). Engraftment occurred on time in all patients and there was one treatment-related death resulting in an overall mortality rate of 4.8% among the 21 patients treated with HDC. The response rate was 72% (48% CR, 24% PR) and the mean time to progression and overall survival after HDC were 7 and 32 months, respectively. CONCLUSION: HDC could be performed safely in patients with advanced ovarian cancer. However, even with a high response rate, the duration of response is short, warranting new treatment approaches to further improve the outcome of this population of patients with unfavorable prognosis.
The luciferase reporter gene incorporated into adenoviral vectors is very useful for monitoring viral transduction of different cell types or for comparing the transduction efficiency of different viral constructs of one cell type. Luciferase protein expression can be detected and quantified with very high sensitivity from whole cells or organ extracts. However, its disadvantages become obvious when aiming at evaluation of transduction events at the single cell level. The results obtained from whole cell extracts cannot be directly correlated to single cell events. In this paper direct cellular luciferase imaging using cell permeable luciferin substrates is applied for comparative analysis of cellular transduction events by two adenoviral vectors with different cell binding properties. Using digital imaging microscopy we show a more than ten-fold increase in transduction efficiency by Ad5LucRGD vectors versus AdCMVLuc vectors on human A549 cells.
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We studied cytokeratin-positive (CK+) cells in the bone marrow (BM) and tumor markers (TM) in the blood of 128 patients with primary breast cancer in order to obtain an early diagnosis of residual disease. CK+ cells of two BM aspirations were detected by immunocytochemistry (IC). To evaluate the usefulness of immunomagnetic separation (IMS) for tumor cell enrichment in clinical samples, IMS was performed prior to IC and compared with the results for IC alone. The overall CK+ rate was 34% (44/128 patients), 29% (15/51) for patients with T1 tumors, 33% (28/84) for N0 patients and 31% (26/82) for patients with G1-2 breast carcinoma. Interestingly, 67% of CK+ patients were only positive in one of the two aspirates studied. A comparison between IC alone and IMS/IC could be performed in 70/128 patients (28/70 CK+). In 6/28 patients, CK+ cells were detected by both methods, in 16/28 patients only by IC and in 6/28 patients only by IMS. At least one TM, including carcinoembryonic antigen, carbohydrate antigen 15-3 and tissue polypeptide antigen, was increased in 58/128 (45%) patients [21/58 (36%) were CK+ in the BM]. Surprisingly, levels for the extracellular domain of Her-2/neu in serum samples were within the normal range in every patient studied. After a 2-year follow-up, 7/128 patients relapsed (3/7 CK+/TM-; 2/7 CK-/TM+; 2/7 CK-/TM-). We conclude that studying two BM aspirates for CK+ cells by IC in combination with TM determination is useful for identifying patients with a higher risk for relapse, however, tumor cell enrichment techniques will have to be improved for clinical use.
Overexpression of O(6)-methylguanine DNA methyltransferase (MGMT) can protect hematopoietic cells from O(6)-alkylation damage. To identify possible clinical applications of this technology we compared the effect of MGMT gene transfer on the hematotoxicity induced by different O(6)-alkylating agents in clinical use: the chloroethylnitrosoureas ACNU, BCNU, CCNU and the tetrazine derivative temozolomide. In addition, various retroviral vectors expressing the MGMT-cDNA were investigated to identify optimal viral backbones for hematoprotection by MGMT expression. Protection from ACNU, BCNU, CCNU or temozolomide toxicity was evaluated utilizing a Moloney murine leukemia virus-based retroviral vector (N2/Zip-PGK-MGMT) to transduce primary murine bone marrow cells. Increased resistance in murine colony-forming units (CFU) was demonstrated for all four drugs. In comparison to mock-transduced controls, after transduction with N2/Zip-PGK-MGMT the IC50 for CFU increased on average 4.7-fold for ACNU, 2.5-fold for BCNU, 6.3-fold for CCNU and 1.5-fold for temozolomide. To study the effect of the retroviral backbone on hematoprotection various vectors expressing the human MGMT-cDNA from a murine embryonic sarcoma virus LTR (MSCV-MGMT) or a hybrid spleen focus-forming/murine embryonic sarcoma virus LTR (SF1-MGMT) were compared with the N2/Zip-PGK-MGMT vector. While all vectors increased resistance of transduced human CFU to ACNU, the SF1-MGMT construct was most efficient especially at high ACNU concentrations (8-12 microg/ml). Similar results were obtained for protection of murine high-proliferative-potential colony-forming cells. These data may help to optimize treatment design and retroviral constructs in future clinical studies aiming at hematoprotection by MGMT gene transfer.
The detection of chimerism, residual molecular and cytogenetic disease following transplantation of peripheral blood stem cells (PBSCT) with a nonmyeloablative conditioning (n = 9) and the transplantation of highly purified CD34(+) stem cells (CD34(+) PBSCT) (n = 16) were compared to unmanipulated bone marrow transplantation (BMT) (n = 69) and unmanipulated PBSCT (n = 50) after myeloablative conditioning in patients with first chronic phase of chronic myelogenous leukemia (CML) (n = 137), second chronic phase of CML (n = 4), acute lymphoblastic leukemia (n = 2) and acute myeloid leukemia (n = 1). A molecular relapse (MR) as defined by two consecutive positive polymerase chain reaction assays for the detection of M-bcr-abl transcripts (n = 141) and cbfbeta-myh11 transcripts (n = 1) in a 4-week interval was found in 10 of 16 patients (63%) after CD34(+) PBSCT, and in 27 of 69 patients (39%) after BMT, whereas only three of 50 patients (6%) after PBSCT (P < 0.001) and one of eight patients (13%) after PBSCT with reduced conditioning suffered from a MR. A cytogenetic relapse occurred in five of 16 patients (31%) after CD34(+)PBSCT and 21 of 69 patients (30%) after BMT (NS) compared to two of 50 patients (4%) after PBSCT and none of the eight patients after PBSCT with reduced conditioning (P < 0.05). The lowest treatment-related mortality was seen in the 16 patients after CD34(+) PBSCT, who are all currently alive with a median follow-up of 15 months, whereas the survival rate for BMT, PBSCT and PBSCT with reduced conditioning were 65%, 63% and 58%, respectively. Multivariate analysis including all potential influential factors of post-transplant residual disease recurrence showed that patients after CD34(+) PBSCT had a significantly higher risk (two times) to develop a MR than patients after BMT (P < 0.03), whereas patients after unmanipulated PBSCT had a significant lower risk (eight times) for the occurrence of a MR post transplant (P < 0.001). Patients after BMT and CD34(+) PBSCT had the lowest rates of complete chimerism (CC) at 3 months after transplant. Only five of nine patients (55%) after CD34(+) PBSCT and 19 of 33 patients (58%) after BMT achieved CC compared to 19 of 22 (86%) patients after PBSCT and seven of eight (88%) patients after PBSCT with reduced conditioning (P < 0.05).
We have used a new single-step real-time reverse transcription polymerase chain reaction (RT-PCR) method to quantify BCR-ABL transcripts, thereby estimating the relapse stage in chronic myeloid leukaemia patients after allogeneic transplants. In 402 samples from 172 patients, BCR-ABL expression was determined and normalized, using the GAPDH housekeeping gene product as an endogenous reference. In our real-time RT-PCR assay, serial dilutions of RNA of the K562 cell line remained positive down to 7.5 pg. The median normalized BCR-ABL amount differed significantly (P < 0.001) between the various disease stages and was 0.06% (range 0.001-1.55%), 3.2% (range 1.4-5.6%) and 21.5% (range 6.8 -827%) in 17 patients with a molecular relapse, in eight patients with a cytogenetic relapse and in 10 patients with a haematological relapse respectively.
MspA is an extremely stable, oligomeric porin from Mycobacterium smegmatis that forms water-filled channels in vitro. Immunogold electron microscopy and an enzyme-linked immunosorbent assay demonstrated that MspA is localized in the cell wall. An mspA deletion mutant did not synthesize detectable amounts of mspA mRNA, as revealed by amplification using mspA-specific primers and reverse-transcribed RNA. Detergent extracts of the DeltamspA mutant exhibited a significantly lower porin activity in lipid bilayer experiments and contained about fourfold less porin than extracts of wild-type M. smegmatis. The chromosome of M. smegmatis encodes three proteins very similar to MspA. Sequence analysis of the purified porin revealed that mspB or mspC or both genes are expressed in the DeltamspA mutant. The properties of this porin, such as single channel conductance, extreme stability against denaturation, molecular mass and composition of 20 kDa subunits, are identical to those of MspA. Deletion of mspA reduced the cell wall permeability towards cephaloridine and glucose nine- and fourfold respectively. These results show that MspA is the main general diffusion pathway for hydrophilic molecules in M. smegmatis and was only partially replaced by fewer porins in the cell wall of the DeltamspA mutant [corrected] This is the first experimental evidence that porins are the major determinants of the exceptionally low permeability of mycobacteria to hydrophilic molecules.
PURPOSE: We evaluated whether dose-intensive or high-dose chemotherapy can eliminate micrometastases in high-risk breast cancer patients. EXPERIMENTAL DESIGN: We monitored cytokeratin (CK)/17-1A positive cells in the bone marrow (BM) and peripheral blood stem cells (PBSC) and studied Her-2/neu serum levels of patients with locally advanced (n = 13; group 1) and metastatic breast cancer (n = 30; group 2) using immunomagnetic separation, immunocytochemistry, and ELISA. RESULTS: CK+ cells were found in the BM of 3 of 13 (23%) group 1 patients before but not after chemotherapy, resulting in an overall survival (OS) of 92% after a median follow-up of 33 months. Contamination of PBSC in 2 of 9 (22%) patients was not associated with decreased survival. In group 2 patients, the CK+ rate was 60% (18 of 30 patients) before and 40% (4 of 10 patients) after therapy with an OS rate of 43% after 29 months. PBSC samples were positive in 7 of 24 (29%) patients. CK+ BM and PBSC led to a rapid progress and short OS, whereas tumor cell-free BM and PBSC resulted in a mean OS of 30 months. The antigen 17-1A was detected on most CK+ cells in both patient groups before therapy, on all of CK+ PBSC, and on CK+ cells in group 2 patients after therapy. Increased Her-2/neu levels were found in group 2 patients before chemotherapy. CONCLUSION: Micrometastatic cells are present in PBSC grafts and can survive even high-dose chemotherapy. The presence of immunotherapeutic target antigens supports the idea that a combined chemoimmunotherapy might be successful in eliminating minimal residual disease.
Hemizygous deletions of the fragile histidine triad (FHIT) gene at human chromosome band 3p14.2 and down-regulation of its gene product are found in the majority of renal cell carcinomas (RCCs). Functional tumor suppressive activity of Fhit in renal cancer cells previously was observed in RCC cell line RC48, which lacks endogenous Fhit expression. To further investigate the potential role of FHIT as a tumor suppressor gene in RCC, we transfected FHIT cDNA expression constructs into RCC cell lines RCC-1 and SN12C, which show low-level expression of endogenous Fhit and reveal an intact von Hippel-Lindau (VHL) gene. Stable transfectants of both cell lines showed no alterations of cell morphology, proliferation kinetics, or cell cycle parameters in vitro. The FHIT gene transfer rate, however, was significantly lower in RCC-1 cells compared with SN12C cells, suggesting a selection against exogenous Fhit expression. In addition, in nude mouse assays, a significant delay of tumor formation was observed for FHIT-transfected RCC-1 cell lines, with outgrowing tumors demonstrating loss of Fhit expression in the majority of cells. In contrast, tumorigenicity of FHIT-transfected SN12C cell clones was not suppressed, despite stable transgene expression. In conclusion, our results demonstrate a selective tumor suppressive activity of Fhit in RCC cells in vivo and suggest that the susceptibility to suppression is not restricted to cancer cells with complete loss of Fhit expression.
PURPOSE: Although gene transfer with retroviral vectors has already been applied to patients as part of clinical protocols, low expression of transgenes in target cells still remains a problem. Therefore, we compared various retroviral vectors using different promoters and backbones for expression of the enhanced green fluorescent protein (EGFP) reporter gene in fibroblasts and CD34+ cells. METHODS: The N2A retroviral vector was used to test expression from the herpes simplex virus thymidine kinase promoter (vector N2A-TK-EGFP), a human phosphoglycerate kinase promoter (vector N2A-PGK-EGFP), and the SV40 promoter (vector N2A-SV-EGFP). Additional constructs used the spleen focus-forming virus (SFFV) long terminal repeat (LTR) as promoter and expressed EGFP alone (vector SFbeta1-EGFP) or EGFP and a downstream (vector SFbeta1-EGFP-IRES) or upstream (vector SFbeta1-IRES-EGFP) internal ribosomal entry site. RESULTS: For NIH 3T3 cells the fluorescence-activated cell sorting analysis revealed that the most active internal promoter was the SV40 promoter in the vector N2A-SV-EGFP (mean fluorescence intensity, MFI, 66.7 +/- 0.4), followed by N2A-PGK-EGFP (26.3 +/- 1.8 MFI), and N2A-TK-EGFP (4.8 +/- 0.1 MFI). Expression from the SFbeta1-EGFP vector (82.6 +/- 6.7 MFI) and the SFbeta1-EGFP-IRES vector (102.8 +/- 6.2 MFI) was higher than from SFbeta1-IRES-EGFP vector (15.5 +/- 1.8 MFI). In human CD34-positive cells, the EGFP expression from all vectors was considerably lower than in fibroblasts with the SFbeta1-EGFP vector still being four- to fivefold more active than the internal promoters tested. CONCLUSION: The SFFV LTR seems to allow a high expression of transgenes, as long as the transgene is not expressed downstream of an internal ribosomal entry site. Internal promoters may be useful for targeted gene expression in specific cell types, but the reduced level of expression from some internal promoters has to be taken into consideration.
The use of the real-time reverse-transcription polymerase-chain reaction (RT-PCR) method to quantify BCR-ABL transcripts before and after allogeneic transplant was prospectively studied in 65 patients with chronic myeloid leukemia (CML). The expression of the BCR-ABL transcript was determined and normalized using the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) housekeeping gene product as an endogenous reference. In the single step real-time PCR assay, tenfold serial dilutions of cDNA of the K5652 cell line remained positive down to 100 pg cDNA only. However, molecular relapses of CML after transplant were only safely detectable when a nested real-time PCR assay was performed, which was able to detect 1-10 pg cDNA from a tenfold serial dilution. The median normalized BCR-ABL transcript level was measured as 0.004% in 17 patients with a molecular relapse, 0.4% in 7 patients with a cytogenetic relapse, 2.6% in 36 patients with a stable phase of CML, and 36% in 5 patients with a relapse in a blast crisis. The analyzed median normalized amount of BCR-ABL transcript differed significantly (P<0.001) between the various disease stages. In ten CML patients with relapse, the real-time PCR method was used to monitor the response of various immunotherapies as donor leukocyte infusions, withdrawal of immunosuppression, or interferon-alpha application. The results of the quantitative evaluation of BCR-ABL transcripts reflected very well the clinical effect of the different applied immunotherapies. The new real-time PCR method seems to be a suitable technique for the early detection of relapse after allogeneic transplant in patients with the BCR-ABL transcript. Its ability to distinguish between molecular and cytogenetic relapse (P<0.001) allows early therapeutic decisions.
We treated 153 patients with de novo acute myeloid leukemia (AML) with two induction courses of conventional-dose cytosine arabinoside (ara-C) and idarubicin (AIDA) followed by either a third course of AIDA, high-dose ara-C or bone-marrow transplantation. The complete remission (CR) rate for all patients was 63.4%, with a higher CR rate for patients with a normal (versus unfavorable) karyotype (73.2% vs 52.5%; P=0.038). The probability of overall survival (OS) was 30.7% after 5 years (26.3% after 7 years). Improved OS at 5 years could be observed for patients up to 50 years old versus patients older than 50 years of age (37.6% vs 19.9%; P=0.001) and patients with a normal (versus unfavorable) karyotype (42.9% vs 14.1%; P=0.0016). Disease-free survival (DFS) after 5 years was 33.2% for all 97 CR patients and was significantly better for patients with a normal (versus unfavorable) karyotype (44.3% vs 12.3%; P= 0.003). Multivariate analysis revealed that the age for OS (P < 0.02) and the karyotype for both OS (P<0.03) and DFS (P< 0.05) were independent prognostic factors. In conclusion, AIDA is an effective and well-tolerated induction regimen (even in elderly patients) with a 5-year survival of more than 30% when combined with ara-C-containing postremission therapy. The karyotype is the most powerful prognostic factor for predicting the outcome of patients treated with this protocol.