Biomedical subjects

J Whang-Peng

Publications and source records attributed to J Whang-Peng.

At least 19 recordsLinked to original sources

PubMed2005

alpha-fetoprotein response predicts survival benefits of thalidomide in advanced hepatocellular carcinoma.

BACKGROUND: Radiographic measurements do not always reflect the biological response of hepatocellular carcinoma to drug therapy. AIMS: To evaluate the clinical implications of tumour marker (alpha-fetoprotein) response in advanced hepatocellular carcinoma patients with thalidomide treatment. PATIENTS AND METHODS: Forty-two advanced hepatocellular carcinoma patients with baseline alpha-fetoprotein levels above 200 ng/mL and thalidomide therapy were included. Serum alpha-fetoprotein levels were measured every 4 weeks. alpha-fetoprotein response was defined as a 50% or greater reduction of alpha-fetoprotein levels for 4 or more weeks during treatment. Radiographic response was assessed by World Health Organization criteria; survivals were estimated by Kaplan-Meier method and prognostic factors were assessed by Cox's proportional hazard model. RESULTS: With intention-to-treat analysis, radiographic response and alpha-fetoprotein response were obtained in 7% (three of 42, 95% confidence interval: 0-15) and 24% (10 of 42, 95% CI: 10-38) of patients, respectively. All radiographic response was observed in alpha-fetoprotein responders. Multivariate analyses showed alpha-fetoprotein response was independent prognostic factor for both progression-free survival (relative risk = 0.394, 95% CI: 0.189-0.820, P = 0.013) and overall survival (relative risk = 0.241, 95% CI: 0.096-0.606, P =0.003), whereas radiographic response was not. CONCLUSION: alpha-fetoprotein response can more accurately reflect the biological response of advanced hepatocellular carcinoma to thalidomide therapy than radiographic response.

Aged↗

PubMed2005

Stage migration influences on stage-specific survival comparison between D1 and D3 gastric cancer surgeries.

AIMS: We evaluate the influency stage migration in a randomised trial comparing D1 (N 1 lymphadenectomy) and D3 (N 1, 2 and 3 lymphadenectomy) dissections. METHODS: Two hundred and thirteen curatively resected patients were analysed, with this TNM data. RESULTS: After applying D3 patients' data according to simulated D1 staging, D3 resections were associated with up-staging to N2-3 levels in 8% of patients according to the N stage. The likelihood of N-status migration increased with increasing depth of invasion into the gastric wall. The increases in the calculated survival rate after stage migration on known 5-year survival rates were: 2% in stage IB, 1% in stage II, 4% in stage IIIA, and 1% in stage IIIB. CONCLUSIONS: Stage migration secondary to meticulous lymph node dissection affects stage-specific survival rates. True therapeutic survival benefit of D3 resection can only be assessed in this context.

Gastrectomy↗

PubMed2005

Pulmonary embolism after transcatheter arterial chemoembolization.

Metastatic hepatic tumours can be treated with hepatic transcatheter arterial chemoembolization (TACE). Common complications associated with TACE include hepatic insufficiency, fever, and pain. However, pulmonary embolism is rarely documented as a fatal adverse effect. We report a case of pulmonary embolism following TACE in a renal cell carcinoma patient with liver metastases. Total recovery is noted after the effective treatment.

Aged↗

PubMed2004

A randomised phase II study of weekly paclitaxel or vinorelbine in combination with cisplatin against inoperable non-small-cell lung cancer previously untreated.

Phase II studies have suggested that weekly paclitaxel has a higher response rate and better toxicity profile than the conventional schedule of once every 3 or 4 weeks. Our aim was to evaluate the efficacy of weekly paclitaxel plus cisplatin (PC) vs vinorelbine plus cisplatin (VC) in chemonaïve non-small-cell lung cancer (NSCLC) patients. From October 2000 to May 2002, 140 patients were enrolled. The treatment dose was P 66 mg m(-2) intravenous infusion (i.v.) on days 1, 8, and 15, and C 60 mg m(-2) i.v. on day 15, or V 23 mg m(-2) i.v. on days 1, 8, and 15, and C 60 mg m(-2) i.v. on day 15, every 4 weeks. In all, 281 cycles of PC and 307 cycles of VC were given to the patients in the PC and VC arms, respectively. There were 26 partial responses and one complete response (overall 38.6%) in the PC arm, and no complete responses, but 27 partial responses (overall 38.6%) in the VC arm. Myelosuppression was more common in the VC arm (P<0.001). Peripheral neuropathy and myalgia were significantly more common in the PC arm (P<0.001). The median time to disease progression was 6 months in the PC arm and 8.4 months in the VC arm (P=0.0344). The median survival time was 11.7 months in the PC arm and 15.4 months in the VC arm (P=0.297). We concluded that weekly PC is not suggested for NSCLC patients due to the relatively shorter progression-free survival and more common nonhaematological toxicities. British Journal of Cancer (2004) 90, 359-365. doi:10.1038/sj.bjc.6601526 www.bjcancer.com

Adult↗

PubMed2004

Randomized clinical trial of morbidity after D1 and D3 surgery for gastric cancer.

BACKGROUND: A randomized comparison of D1 (level 1 lymphadenectomy) and D3 (levels 1, 2 and 3 lymphadenectomy) dissection was performed to evaluate morbidity and effects on survival from gastric cancer. METHODS: A total of 221 patients were studied after resection for gastric cancer, 110 after D1 surgery and 111 after D3 surgery. RESULTS: The morbidity rate was higher after D3 than after D1 resection (17.1 (95 per cent confidence interval (c.i.) 10.1 to 24.1) versus 7.3 (95 per cent c.i. 2.4 to 12.2) per cent respectively; P = 0.012). The difference was largely related to abdominal abscess (8.1 per cent after D3 versus none after D1 resection; P = 0.003). The D3 group had an anastomotic leak rate of 4.5 per cent whereas there was no leakage in the D1 group (P = 0.060). All anastomotic leaks were minor and were managed non-operatively with nutritional support. Patients who had D3 resection had longer operating times, greater blood loss and postoperative drain outputs, and more patients needed blood transfusion. There was no death in either group. The hospital stay was longer after D3 than D1 surgery (mean(s.d.) 19.6(13.9) (range 10-98) versus 15.0(4.0) (range 10-30) days; P = 0.001). CONCLUSION: Extended lymphadenectomy for gastric cancer is associated with more complications than limited lymphadectomy but this does not lead to significant mortality.

Adenocarcinoma↗

PubMed2002

Additive effect of Interleukin-12 and Interleukin-18 on the T-helper cell pathway of malignant pleural effusion.

Interleukin-18 (IL-18) is a novel cytokine with interferon-gamma (IFN-gamma)-inducing activity, thus favoring the T-helper type 1 (Th-1) pathway. The present study attempts to define the role of IL-18 on the functions of lymphocytes isolated from malignant pleural effusions (EAL, effusion-associated lymphocytes). EAL from 10 patients with malignant pleural effusion were incubated with IL-2, IL-12, or IL-18 with/without a alpha CD3 antibody. ELISA, proliferation, and cytotoxicity assays were performed. IL-18 alone was found to have no significant effect on EAL in terms of cytokine production, lymphocyte proliferation, or cytotoxicity against tumor targets. IL-18 also had no significant additive or synergistic effect on IL-2, IL-12, or alpha CD3 co-cultured EAL. However, when IL-18 was used with IL-12, the highest IFN-gamma/IL-10 ratio was derived, suggesting that these two cytokines had an additive effect in leading EAL from the Th-2 to the Th-1 pathway. Furthermore, 1 of 5 patients' EAL had its strongest cytolytic activity against an autologous tumor when the EAL was cultured with IL-2 plus IL-18, as compared with the other 4 patients whose EAL cytolytic activity against autologous tumor was highest when using IL-2 plus alpha CD3. These findings suggest that IL-18 alone did not have a significant effect on EAL, and that IL-18 did not enhance alpha CD3's activity on EAL. However, its additive effect with IL-12 in the Th-1 pathway and with IL-2 in its cytolytic activity against an autologous tumor deserve further studies.

Adenocarcinoma↗

PubMed2002

Expression of epidermal growth factor receptor in head and neck cancers correlates with clinical progression: a multicentre immunohistochemical study in the Asia-Pacific region.

AIMS: With ongoing efforts to target the epidermal growth factor receptor (EGFR)-mediated tumour growth in the treatment of selected human malignancies, there is a need to determine the expression levels of EGFR and to evaluate its prognostic value in various malignancies in the Asia-Pacific region. METHODS AND RESULTS: A total of 172 patients with head and neck squamous cell carcinomas from Australia, Hong Kong, Singapore, and Taiwan were selected for EGFR detection. Immunohistochemical staining was performed to evaluate EGFR expression. EGFR expression was present in 88.4% (152/172) of all cases tested. Specifically, EGFR expression was found in 91.3% (42/46), 84.6% (22/26), 84.1% (37/44), 96.0% (24/25), and 87.1% (27/31) cases of head and neck squamous cell carcinomas from the oral cavity, oropharynx, nasopharynx, hypopharynx, and larynx, respectively. The results demonstrate a stronger EGFR expression in T4 tumours (P=0.017) and later clinical stages (P=0.016). No significant correlation was seen with risk factors, primary tumour site and ethnicity. CONCLUSIONS: The majority of head and neck squamous cell carcinomas express EGFR, indicating the importance of studying the efficacy of anti-cancer therapy through this pathway. The results also show similar rates of receptor expression in head and neck squamous cell carcinoma patients from our region compared with other parts of the world.

Adult↗

PubMed2002

Paclitaxel plus carboplatin, compared with paclitaxel plus gemcitabine, shows similar efficacy while more cost-effective: a randomized phase II study of combination chemotherapy against inoperable non-small-cell lung cancer previously untreated.

BACKGROUND: Paclitaxel (Taxol) plus carboplatin (PC) has shown activity in the treatment of advanced non-small-cell lung cancer (NSCLC). Non-platinum-containing combination chemotherapy, such as paclitaxel plus gemcitabine (PG), has also demonstrated reasonable efficacy. Our aim here was to evaluate the clinical efficacy and cost-effectiveness of PC versus PG in chemo-naive. advanced NSCLC patients. PATIENTS AND METHODS: Ninety (68 male, 22 female) patients were enrolled from August 1999 to August 2000. The performance status was one in 29 patients and two in 16 patients of the PC group, and one in 24 patients and two in 21 patients of the PG group. Seventeen patients had stage IIIb disease and 28 patients stage IV disease in the PC group: 18 patients had stage IIIb disease and 27 patients stage IV disease in the PG group (New International Staging System). Treatment consisted of P 175 mg/m2 and C at AUC = 7 (predicted using measured clearances and the Calvert formula) intravenous infusion (i.v.) on day 1, or P 175 mg/m2 i.v. on day 1 and G 1000 mg/m2 i.v. on days 1 and 8, every 3 weeks. RESULTS: In all, 175 cycles of PC and 184 cycles of PG were given in the PC and PG groups, respectively. The median treatment cycle was four cycles in both groups. All the patients were assessable for toxicity and response measurement. There were three complete responses and 15 partial responses (overall 40%) in the PC group, and no complete response, but 18 partial responses (overall 40%) in the PG group. WHO grades 3/4 leukopenia, anemia and thrombocytopenia occurred in six (13.3%), seven (15.5%) and five patients (11.1%) in the PC group; and in four (8.9%), six (13.3%) and 0 patients in the PG group, respectively. Two patients in each group suffered from grade 3 peripheral neuropathy. Other non-hematological toxicities were mild and few. Median survival time was 14.1 months in the PC group and 12.6 months in the PG group. One-year survival was 50.7% in the PC group and 53.3% in the PG group. The PG group had a higher total expense and expended more days undergoing treatment than the PC group (P = 0.034 and 0.069, respectively). CONCLUSIONS: Both PC and PG combination chemotherapy produce a similar efficacy in the treatment of NSCLC. However, PC is more cost-effective than PG.

Adult↗

PubMed2002

Non-surgical treatment for afferent loop syndrome in recurrent gastric cancer complicated by peritoneal carcinomatosis: percutaneous transhepatic duodenal drainage followed by 24-hour infusion of high-dose fluorouracil and leucovorin.

Afferent loop syndrome (ALS) is a debilitating complication of recurrent gastric cancer. Surgical intervention is usually not feasible in the face of poor general performance, presence of advanced peritoneal carcinomatosis and limited survival of the patients. Non-surgical approaches include internal drainage by stenting at the stenotic or anastomotic site and external drainage via the percutaneous routes. Percutaneous transhepatic duodenal drainage (PTDD) has been shown to provide effective palliation for ALS, but long-term catheterization is usually inevitable. We hereby present two cases of recurrent gastric cancer whose ALS was successfully treated with PTDD followed by weekly 24-h infusion of high-dose 5-fluorouracil and leucovorin (HDFL). PTDD rapidly ameliorated the incapacitating symptoms of ALS, and the effective, low-toxicity chemotherapy subsequently led to tumor regression, restoration of bowel patency and removal of the drainage tube. At present, both patients have remained ALS-free and drainage-free for 16 and 17 months, respectively. Our results indicate that this non-surgical approach with PTDD followed by weekly HDFL could serve as a safe and effective treatment for ALS in recurrent gastric cancer complicated by peritoneal carcinomatosis.

Adenocarcinoma↗

PubMed2001

Inverted repeats as genetic elements for promoting DNA inverted duplication: implications in gene amplification.

Inverted repeats are important genetic elements for genome instability. In the current study we have investigated the role of inverted repeats in a DNA rearrangement reaction using a linear DNA substrate. We show that linear DNA substrates with terminal inverted repeats can efficiently transform Escherichia coli. The transformation products contain circular inverted dimers in which the DNA sequences between terminal inverted repeats are duplicated. In contrast to the recombination/rearrangement product of circular DNA substrates, which is exclusively one particular form of the inverted dimer, the rearrangement products of the linear DNA substrate consist of two isomeric forms of the inverted dimer. Escherichia coli mutants defective in RecBCD exhibit much reduced transformation efficiency, suggesting a role for RecBCD in the protection rather than destruction of these linear DNA substrates. These results suggest a model in which inverted repeats near the ends of a double-strand break can be processed by a helicase/exonuclease to form hairpin caps. Processing of hairpin capped DNA intermediates can then yield inverted duplications. Linear DNA substrates containing terminal inverted repeats can also be converted into inverted dimers in COS cells, suggesting conservation of this type of genome instability from bacteria to mammalian cells.

Animals↗

PubMed2001

Suppression of gene amplification and chromosomal DNA integration by the DNA mismatch repair system.

Mismatch repair (MMR)-deficient cells are shown to produce >15-fold more methotrexate-resistant colonies than MMR normal cells. The increased resistance to methotrexate is primarily due to gene amplification since all the resistant clones contain double-minute chromosomes and increased copy numbers of the DHFR gene. In addition, integration of linearized or retroviral DNAs into chromosomes is also significantly elevated in MMR-deficient cells. These results suggest that in addition to microsatellite instability and homeologous recombination, MMR is also involved in suppression of other genome instabilities such as gene amplification and chromosomal DNA integration.

Adaptor Proteins, Signal Transducing↗

PubMed2001

An analysis of cytokine status in the serum and effusions of patients with tuberculous and lung cancer.

The present study was designed to ascertain whether or not the pleural effusion and serum cytokine levels (granulocyte-macrophage colony-stimulating factor [GM-CSF], interleukin-10 [IL-10], and interferon-gamma [IFN gamma]) in lung cancer patients differ from tuberculous (TB) pleural effusion, in which a strong cellular immune reaction is found; and, whether cytokine levels are a prognostic factor in lung cancer patients with malignant effusion. A total of 202 lung cancer patients with malignant pleural effusion and 26 patients with TB pleural effusion were studied consecutively between 1995 and 1998. Serum and effusion cytokine levels were analyzed with ELISA assays. The results showed that pleural effusion GM-CSF and IL-10 levels were significantly higher than serum levels in both cancer and TB patients. Pleural effusion IFN gamma levels were significantly higher than serum levels in TB patients. IFN gamma levels in both pleural effusion and serum were significantly higher in TB patients than in those with cancer. No significant difference was found, between TB and cancer patients, in the serum or pleural effusion levels of either IL-10 or GM-CSF. The ratio of pleural effusion IFN gamma to serum IFN gamma, effusion IFN gamma to effusion IL-10, and effusion IL-10 to serum IL-10, were all significantly higher in TB than in cancer patients, suggesting a higher cellular activity and T-helper 1 (Th1) reaction in TB pleural effusion than in malignant effusions, which were predominantly Th2 type. Survival analysis showed no significant difference in lung cancer patients with different levels of these cytokines. It was concluded that lung cancer patients with malignant pleural effusion had poorer immune profiles than those with TB pleurisy, both locally and systemically; and the cytokine profiles were not prognostic factors for lung cancer patients with malignant pleural effusion.

Aged↗

PubMed2001

Efficacy of Re-188-labelled sulphur colloid on prolongation of survival time in melanoma-bearing animals.

UNLABELLED: In this study, the effectiveness of a 188Re labeled sulfur colloid with two particle size ranges was used to evaluate the effectiveness of this agent on melanoma tumors in mice in terms of animal lifespan. METHODS: Two separate group of animals were used for investigating biodistribution and survival time. A total of 188 B16F10-melanoma-bearing BDF(1) mice were injected intraperitoneally with 3.7 MBq (0.1mCi)/2mL of radiolabeled sulfur colloid ten days after intraperitoneal inoculation of 5x10(5) B16F10 melanoma cells/2ml. For group 1, 30 mice were sacrificed at 1, 4, 24, 48 and 72 hours for biodistribution studies. In group 2, 158 mice were divided into 9 groups (n=16 approximately 18/groups)each receiving respectively tumor alone, tumor with normal saline, cold colloid or hot colloid with 16, 23, 31, 46, 62, or 124 MBq activity. Each of these colloid groups was further divided into two groups, one receiving smaller particle sizes (<3 microm:80.4 +/-7.2%, colloid 1) and the other receiving larger particle sizes (<3 microm:12.3+/-1.0%, colloid 2). The animals were checked daily until death and their survival recorded. RESULTS: Colloid 2 showed higher accumulation in almost all tissues, the highest accumulation organ was tumor ( approximately 40%), then spleen ( approximately 20%), stomach ( approximately 15%), diaphragm ( approximately 3%), and liver ( approximately 2%). There was a significant increase in survival time with increasing amount of the larger-particle-size colloid. Administered levels of 16-31 MBq/mouse were most efficacious and with higher amounts the survival times decreased significantly below that of the controls. There was a significant difference in the dose-response curves for the two preparations. Protection factors (1/Relative-risk) of nearly 5 were achieved using the larger colloid size, and nearly 30 using the smaller colloid size. An amount of 16-31 MBq of the colloid 2 was the optimal activity in these studies. On the one hand, the survival data agreed well with the biodistribution data, where higher accumulation was found in tumor with colloid 2. CONCLUSION: Rhenium-188 offers on-site availability, medium half-life, higher beta-particle energy of 2.12 MeV for therapy and emission of 155keV gamma photon suitable for imaging. The present study demonstrated that 188Re-sulfur colloid is an effective agent in controlling tumor cells in the abdominal cavity in animals.

Animals↗

PubMed2001

Interleukin-7 and interleukin-12 have different effects in rescue of depressed cellular immunity: comparison of malignant and tuberculous pleural effusions.

The present study attempts to determine the role of interleukin-7 (IL-7) and IL-12 in recovering the functions of the lymphocytes of malignant effusion, in terms of cytokine production, proliferation, and cytolytic activity, compared with lymphocytes from tuberculous pleural effusion. Effusion-associated lymphocytes (EAL) were isolated from tuberculous (tEAL) and malignant (mEAL) pleural effusions. The EAL proliferate response was measured after 3 days in culture. Interferon-gamma (IFN-gamma) production and cytotoxicity against K-562 cells or autologous tumor cells were assessed after 6 days in culture. It was found that the mEAL had depressed proliferation, IFN-gamma production, and cytolytic activity, as compared with tEAL. Stimulation with IL-12 plus IL-2, but not with IL-7 plus IL-2, fully restored the IFN-gamma production of mEAL to that of tEAL levels. In contrast, the proliferate response of mEAL was enhanced significantly more with IL-7 plus IL-2 than with IL-12 plus IL-2. Both the IL-7 plus IL-2 and IL-12 plus IL-2 stimulation of mEAL showed a significant increase in cytolytic activity against autologous tumor cells, although the cytolytic activity against K-562 cells did not increase. These results suggest that tEAL had a higher cellular activity than mEAL. This depressed cellular function of mEAL could be reversed with cytokines. However, different cytokines had different effects on mEAL; for example, IL-7 had a better effect in the stimulation of lymphocyte proliferation compared with IL-12, which had a better effect in driving the lymphocytes to the T helper 1 (TH1) pathway and a higher IFN-gamma production. Both IL-7 and IL-12, in the presence of IL-2, can restore the immunosuppressed cytolytic activity of the lymphocytes of malignant pleural effusion against autologous tumor.

Adjuvants, Immunologic↗

PubMed2000

Vaccination against gonadotropin-releasing hormone (GnRH) using toxin receptor-binding domain-conjugated GnRH repeats.

A method for the preparation of an immunogen containing multiple copies of a self-peptide in linear alignment was designed in order to overcome the difficulty of inducing an immune response to poorly immunogenic peptide antigens. DNA fragments encoding multiple repeats of the self-peptide were generated by a new technique, termed template-repeated polymerase chain reaction (TR-PCR), which could be subcloned into an expression vector for production of peptide repeats as an immunogen. This approach was tested by constructing fusion proteins containing the receptor-binding domain of Pseudomonas exotoxin A and multiple copies of the 10-residue sequence of the peptide hormone gonadotropin-releasing hormone (GnRH). Immunization of female rabbits with the immunogen that contained the exotoxin receptor-binding domain and 12 copies of GnRH (PEIa-GnRH12) resulted in the generation of high-titer antibodies specific for GnRH. Although at equal molar basis of the GnRH moiety, the immunogen that contained single copy of GnRH (PEIa-GnRH1) induced low-titer anti-GnRH antibodies. These observations suggest that the presence of multiple peptide repeats is a key factor in eliciting an immune response. In addition, anti-GnRH antibodies effectively neutralized GnRH activity in vivo, as demonstrated by the degeneration of the ovaries in the injected rabbits. Because anti-GnRH antibody could be functionally analogous to GnRH antagonist, which has been used to treat patients with ovarian cancer, vaccination of PEIa-GnRH12 presents a potential therapeutic application for the treatment of GnRH-sensitive ovarian cancer.

ADP Ribose Transferases↗

PubMed2000

PIK3CA as an oncogene in cervical cancer.

Amplification of chromosome arm 3q is the most consistent aberration in cervical cancer, and is implicated in the progression of dysplastic uterine cervical cells into invasive cancer. The present study employed the 'positional candidate gene' strategy to determine the contribution of PIK3CA, which is located in 3q26.3, in cervical tumorigenesis. PIK3CA is known to be involved in the PI 3-kinase/AKT signaling pathway, which plays an important role in regulating cell growth and apoptosis. The results of comparative genomic hybridization show that the 3q26.3 amplification was the most consistent chromosomal aberration in primary tissues of cervical carcinoma, and a positive correlation between an increased copy number of PIK3CA (detected by competitive PCR) and 3q26.3 amplification was found in tumor tissues and in cervical cancer cell lines. In cervical cancer cell lines harboring amplified PIK3CA, the expression of gene product (p110alpha) of PIK3CA was increased, and was subsequently associated with high kinase activity. In addition, transformation phenotypes in these lines, including increased cell growth and decreased apoptosis, were found to be significantly affected by the treatment of specific PI 3-kinase inhibitor, suggesting that increased expression of PIK3CA in cervical cancer may result in promoting cell proliferation and reducing apoptosis. These evidences support that PIK3CA is an oncogene in cervical cancer and PIK3CA amplification may be linked to cervical tumorigenesis. Oncogene (2000).

Apoptosis↗

PubMed2000

Integration of computer-assembled digital images and text data as evidence for the oncological record.

Digitally created visual images of pertinent patient data have been integrated with text information to formulate a visual evaluation and summary sheet (VESS) using computer processing. The VESS incorporates images of a patient's physical appearance, radiological images, pharmacokinetic graphs, and text information into a 1-page document of the patient's condition. Thus, computer processing of digital images and other information helps to refine patient data presentation, analysis, interpretation, and communication. This form of data management is especially valuable in oncological research, where clinical trials demand rapid, ongoing assessment of results and analysis of large amounts of data. The VESS is an effective mechanism for monitoring both the progress of individual patients and the endpoints of the overall clinical trial.

Diagnostic Imaging↗

PubMed2000

Development of DNA delivery system using Pseudomonas exotoxin A and a DNA binding region of human DNA topoisomerase I.

Gene therapy is defined as the delivery of a functional gene for expression in somatic tissues with the intent to cure a disease. Thus, highly efficient gene transfer is essential for gene therapy. Receptor-mediated gene delivery can offer high efficiency in gene transfer, but several technical difficulties need to be solved. In this study, we first examined the DNA binding regions of the human DNA topoisomerase I (Topo I), using agarose gel mobility shift assay, in order to identify sites of noncovalent binding of human DNA Topo I to plasmid DNA. We identified four DNA binding regions in human DNA Topo I. They resided in aa 51-200, 271-375, 422-596, and 651-696 of the human DNA Topo I. We then used one of the four regions as a DNA binding protein fragment in the construction of a DNA delivery vehicle. Based on the known functional property of each Pseudomonas exotoxin A (PE) domain and human DNA Topo I, we fused the receptor binding and membrane translocation domains of PE with a highly positively charged DNA binding region of the N-terminal 198 amino acid residues of human DNA Topo I. The resulting recombinant protein was examined for DNA binding in vitro and transfer efficiency in cultured cells. The results show that this DNA delivery protein is a general DNA delivery vehicle without DNA sequence, topology, and cell-type specificity. The DNA delivery protein could be used to target genes of interest into cells for genetic and biochemical studies. Therefore, this technique can potentially be applied to cancer gene therapy.

ADP Ribose Transferases↗