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.

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.

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.

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.

Phase II study with gemcitabine, ifosfamide and cisplatin in advanced non-small cell lung cancer

The aim of the present study was to determine the clinical activity and toxicity of a novel chemotherapy combination regimen of gemcitabine, ifosfamide and cisplatin (GIP), administered every 3 weeks, in patients with inoperable non-small cell lung cancer (NSCLC). From October 1998 to July 1999, 18 previously untreated stages IIIb (4) and IV (14) patients were enrolled into the study. Gemcitabine and ifosfamide (with mesna as uroprotection) was administered on days 1 and 6, at a dose of 1000 and 1500 mg/m2, respectively; and cisplatin was given on day 1 at a dose of 60 mg/m2, every 3 weeks. All 18 patients were evaluable for response and toxicity profiles. One patient achieved a complete response, and II patients achieved a partial response, with an overall response rate of 66.7% (95%, CI, 45-89%). The main toxicity was hematological, a NCI grade 3-4 neutropenia in 16 patients (88.9%) during the treatment course. Febrile neutropenia occurred in three patients (16.6%). Grade 3 anemia occurred in eight patients (44.41%) and grade 3-4 thrombocytopenia occurred in 11 patients (61.1%). Non-hematological toxicity was mild and tolerable. No toxic death occurred. The median survival was 12.7 months and 1 year survival was 58.4%. The GIP combination chemotherapy produced a high response rate in advanced NSCLC; however, there was a relatively high percentage of hematological toxicity that still could be tolerated. A randomized trial comparing GIP to a two-drug combination of gemcitabine and cisplatin is planned.

Phase II study of tamoxifen, ifosfamide, epirubicin and cisplatin combination chemotherapy in patients with non-small cell lung cancer failing previous chemotherapy

We conducted a phase II study of tamoxifen, ifosfamide, epirubicin, and cisplatin (TIEP) chemotherapy in patients with non-small cell lung cancer (NSCLC) who had failed previous chemotherapy, in order to assess the response and toxicity of TIEP. Between November 1997 and May 1999, 25 patients were treated. Twelve of the 25 patients (48%) had been previously treated with cisplatin-based combination chemotherapy. TIEP doses were tamoxifen 60 mg oral twice daily on days 1-3; ifosfamide 2.4 g/m(2) intravenous infusion (IV) 60 min with mesna on day 2; epirubicin 40 mg/m(2) IV bolus on day 2; and cisplatin 50 mg/m(2) IV 60 min on day 2 every 4 weeks for up to six cycles. Seventy one cycles were given to 25 patients, with a median of three cycles (range one to six cycles). All patients were evaluable for toxicity profile and response rate. As expected, the major toxicity was myelosuppression. Grade 3 or 4 neutropenia occurred in 15 patients (60%) during treatment, as well as in 31% of the total courses. Febrile neutropenia occurred in two patients. No toxic death occurred in this study. Grade 3 thrombocytopenia occurred in five patients with five cycles. Toxicities other than myelosuppression were few and mild in severity. After two cycles of treatment, five of 25 patients (20%) had a partial response (95% confidence interval 4.3-35.7%). Among 12 patients previously treated with cisplatin-based chemotherapy, three patients (25%) achieved a partial response. The median time to disease progression was 4.9 months and median survival was 7.7 months. The response rate and median survival were better than in our previous study of salvage chemotherapy with ifosfamide, 5-FU, and leucovorin; and with ifosfamide, epirubicin, 5-FU, and leucovorin. In conclusion, TIEP appears to be an active combination regimen with an acceptable toxicity profile in Chinese patients with NSCLC who have failed previous chemotherapy.

Combination chemotherapy with tamoxifen, ifosfamide, epirubicin and cisplatin in extensive-disease small-cell lung cancer

BACKGROUND

A study of tamoxifen, ifosfamide, epirubicin and cisplatin (TIEP) chemotherapy was conducted in patients with extensive-disease, small-cell lung cancer (SCLC) to assess response and toxicity.

METHODS

From November, 1997, to February, 1999, 11 patients were treated, including six chemo-naïve patients and five patients previously treated with cisplatin plus etoposide (EP). The treatment regimen included tamoxifen 60 mg twice daily orally on days 1 to 3, ifosfamide 3 g/m2 intravenous (i.v.) infusion for 60 minutes with mesna on day 2, epirubicin 50 mg/m2 i.v. bolus on day 2 and cisplatin 60 mg/m2 i.v. for 60 minutes on day 2, every 4 weeks for up to six cycles.

RESULTS

All patients were evaluated for toxicity and response rate. As expected, the major toxicity was myelosuppression. Grade 3 or 4 leukopenia or neutropenia occurred in all patients during treatment. Two patients (18.2%) experienced fever in association with the neutropenia, one of whom died of sepsis. Grade 3 anemia occurred in two patients (18.2%) during treatment. Toxicities other than neutropenia and anemia were limited. After two cycles of treatment, five of six chemo-naïve patients (83%), and one of five previously treated patients (20%) attained a partial response (overall 54.5%, 95% confidence interval 25%-83.9%). Median survival time was 8.5 and 6 months in chemo-naïve and previously EP-treated patients, respectively. The response rate and median survival time in chemo-naïve patients did not improve compared with a previous study of ifosfamide plus etoposide undertaken 4 years earlier.

CONCLUSIONS

Although TIEP is an active combination regimen with an acceptable toxicity profile in Chinese patients with extensive-disease SCLC, it showed no remarkable benefit compared with other regimens used in chemo-naïve patients. The 20% response rate and median survival of 6 months in EP-treated patients deserve further study.

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.

A multicenter phase II trial of vinorelbine plus gemcitabine in previously untreated inoperable (Stage IIIB/IV) non-small cell lung cancer

STUDY OBJECTIVE

Vinorelbine and gemcitabine are two active single agents used in the treatment of non-small cell lung cancer (NSCLC). A clinical trial was conducted to evaluate the efficacy and toxicity of vinorelbine plus gemcitabine in patients with inoperable (stage IIIB or IV) NSCLC.

DESIGN

A multicenter phase II study. Vinorelbine, 20 mg/m(2), was given as a 10-min IV infusion, followed by a 30-min IV infusion of gemcitabine, 800 mg/m(2), on days 1, 8, and 15 of each 28-day cycle.

PATIENTS AND MEASUREMENTS

From March 1998 to August 1998, 40 patients were enrolled in the study. The efficacy and toxicity of the treatment were recorded.

RESULTS

All patients are evaluable for treatment response and toxicity profile. Two patients achieved a complete response, and 27 patients achieved a partial response, with an overall response rate of 72.5% (95% confidence interval, 58.7 to 86.3%). Median survival time was 11 months. The significant (World Health Organization grade, 3/4) toxicities were myelosuppression, including leukopenia (47.5% of patients), anemia (17.5% of patients), and thrombocytopenia (12.5% of patients). However, febrile neutropenia occurred in three patients and accounted for one treatment-related death. Fatigue, or flu-like syndrome, occurred in 17 patients, and the symptoms were reversed spontaneously 1 to 2 days after injection in 10 patients. Another seven patients needed dose reduction to ameliorate symptoms. Interstitial pneumonitis occurred in six patients who recovered after steroid treatment. No patient suffered from grade 3 or 4 nausea/vomiting.

CONCLUSION

The combination of vinorelbine and gemcitabine in patients with advanced NSCLC is a highly active non-cisplatin-containing regimen with an acceptable toxicity profile.

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).

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.

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.

In vitro evaluation of GL331's cancer cell killing and apoptosis-inducing activity in combination with other chemotherapeutic agents

GL331 is a novel podophyllotoxin-derived compound and is more efficacious than its congener VP-16 in killing several types of cancer cells, that has promoted considerable interest in its possibility of clinical use. In this study, we found that the higher cytotoxicity of GL331 in nasopharyngeal carcinoma NPC-TW01 cells was attributed to the elevated ability to induce apoptotic cell death. In addition to evaluation of GL331's single agent activity, the use of GL331 in combination with other established therapeutic agents was also evaluated. We found that GL331-induced cell cycle perturbation occurred upon initial 8-h exposure, and pretreatment of NPC-TW01 cells with GL331 for 8 h significantly interfered with the cytotoxicities of VP-16, cisplatin, 5-fluorouracil and adriamycin. When the schedule of drug administration was reversed, high-toxic concentrations of these agents revealed an antagonistic effect on GL331; however, their low-toxic doses had the additive or even more-than-additive effect on the cytotoxicity induced by GL331 at 0.1 microM or less, but for GL331 concentrations of greater than 1 microM, the effect became less than additive. These data suggest that overlapping mechanisms could be elicited by GL331 and other agents, and additional preclinical studies are needed to determine the optimal dose combination and administration schedule that will enhance, rather than interfere with, the efficacy of GL331 in combination with other anti-cancer agents.

A phase II trial of tamoxifen, ifosfamide, epirubicin, and cisplatin combination chemotherapy for inoperable non-small-cell lung cancer

A phase II trial of tamoxifen, ifosfamide, epirubicin, and cisplatin (TIEP) chemotherapy was conducted in patients with chemonaive inoperable non-small-cell lung cancer (NSCLC) to assess response and toxicity. From October 1997 to August 1998, 19 patients were treated. The treatment schema included tamoxifen 60 mg twice daily by mouth on days 1 to 3, ifosfamide 3 g/m2 intravenous infusion (IV) 60 minutes with mesna on day 2, epirubicin 50 mg/m2 IV bolus on day 2, and cisplatin 60 mg/m2 IV 60 minutes on day 2 every 4 weeks for up to six cycles. All patients were evaluable for response and toxicity. The major toxicity was myelosuppression; grade 3 or 4 leukopenia or neutropenia occurred in 14 of 19 (73.7%) patients during treatment, and 6 patients (31.6%) experienced fever in association with the neutropenia; no toxic deaths occurred. Grade 3 anemia occurred in six patients (31.6%) during the treatment. Grade 3 or 4 nausea/vomiting occurred in only one patient. Toxicities other than neutropenia and anemia were minimal. After two cycles of treatment, 9 of 19 patients attained a partial response (47.4%, 95% confidence interval 24.9%-69.9%) in this study. The median time to disease progression was 6 months and median survival time was 12 months. We conclude that TIEP is an active combination regimen with an acceptable toxicity profile in Chinese patients with inoperable NSCLC.

A phase II trial of vinorelbine and cisplatin in previously untreated inoperable non--small-cell lung cancer

Weekly vinorelbine injection with cisplatin had been used in treatment of non-small-cell lung cancer. We performed a phase II trial to evaluate the efficacy and toxicity of a new schedule of vinorelbine and cisplatin in patients with previously untreated, inoperable (stage IIIB or stage IV) non-small-cell lung cancer. From April 1996 to May 1997, 52 patients were enrolled for study, and 50 patients were eligible and evaluable for both response and toxicity assessment. Therapy consisted of vinorelbine, 30 mg/m2, intravenously on days 1 and 5 of a 21-day cycle, and cisplatin 100 mg/m2 (reduced to 80 mg/m2 after the first seven patients) given on day 1. A total of 211 treatment courses were administered; the median number of cycles administered per patient was 4.5 (range: 1-6), the median dose intensity for vinorelbine was 16.9 mg/m2/week (84.4%), whereas that of cisplatin was 22.8 mg/m2/week (84.7%). Twenty-five patients responded to therapy for an overall response rate of 50%; one patient attained a complete response (2%). The main toxicities were vomiting, myelosuppression, and diarrhea, which included World Health Organization grade 3 or 4 nausea/vomiting (58% patients), anemia (41% patients), neutropenia (12% patients), and diarrhea (14%). The median duration of responses was 9 months. The median time to disease progression was 6.8 months (range 0.4-18.1 months). Median survival was 13 months, and 54% of patients were alive at 1 year. We conclude that this new schedule of vinorelbine and cisplatin achieves a high response with acceptable toxicity profile in patients with advanced non-small-cell lung cancer.

Depressed cytolytic activity of peripheral blood mononuclear cells in unusually high paclitaxel concentrations: reversal by IL-2 and IL-12

BACKGROUND

Human lymphocyte function was inhibited by high concentrations of paclitaxel and the effect was reversed by interleukin (IL)-2. However, there was no parallel study determining the relationship between paclitaxel concentrations in the lymphocyte cultures and pharmacokinetic analysis in human patients, nor was there any study on the reversal by cytokines, other than IL-2, of the paclitaxel-induced suppression of lymphocyte cytotoxicity.

METHODS

We tested the effect of different doses of paclitaxel with various incubation times on the cytolytic activity of peripheral blood mononuclear cells (PBMNCs) against K-562 target cells.

RESULTS

Our results showed that using a schedule similar to that for treating patients with tolerable doses of paclitaxel, no inhibition of cytolytic activity of PBMNCs was seen. When the paclitaxel concentration was increased 10-fold, the cytolytic activity of PBMNCs was significantly reduced. This suppression was reversed by the simultaneous addition of a low dose (10 U/ml) of IL-2 or IL-12. Addition of granulocyte macrophage-colony stimulating factor (10 U/ml) did not affect the cytolytic activity of PBMNCs, whereas addition of IL-4 reduced it. Time kinetic studies revealed that, with the addition of IL-2 or IL-12, most of the mononuclear cellular cytolytic activity recovered within 48 to 72 hours.

CONCLUSIONS

These findings suggested that, to reduce the toxicity on mononuclear cellular function when high-dose paclitaxel treatment is elected in clinical practice, paclitaxel should be infused over a longer duration of time, or the treatment should be combined with the administration of a low dose of IL-2 or IL-12.

The significance of body weight change in non-Hodgkins lymphoma

BACKGROUND

The purpose of this study was to evaluate the effect of weight changes after completion of chemotherapy on the prognosis and survival of patients with intermediate and high grade non-Hodgkin's lymphoma.

MATERIALS AND METHODS

A retrospective analysis of data on patients from the TCOG T1488 protocol, a phase II study using CHOP in the treatment of intermediate and high grade lymphoma. From September, 1988 to December 1994, 138 adult patients had complete weight data for analysis. Weight gain in lymphoma patients after therapy significantly correlated with improved survival (Logrank test p = .0031). In patients with initial B symptoms, weight gain after therapy correlated with survival (Logrank test p = .0039), female patients (odds ratio = 6.2) were less likely to gain weight on treatment.

CONCLUSION

Weight gain after chemotherapy for lymphoma is a significant positive prognostic factor for survival.

The status of the do-not-resuscitate order in Chinese clinical trial patients in a cancer centre

OBJECTIVE

To report and analyse the pattern of end-of-life decision making for terminal Chinese cancer patients.

DESIGN

Retrospective descriptive study.

SETTING

A cancer clinical trials unit in a large teaching hospital.

PATIENTS

From April 1992 to August 1997, 177 consecutive deaths of cancer clinical trial patients were studied.

MAIN MEASUREMENT

Basic demographic data, patient status at the time of signing a DNR consent, or at the moment of returning home to die are documented, and circumstances surrounding these events evaluated.

RESULTS

DNR orders were written for 64.4% of patients. Patients in pain (odds ratio 0.45, 95% CI 0.22-0.89), especially if requiring opioid analgesia (odds ratio 0.40, 95% CI 0.21-0.77), were factors associated with a higher probability of such an order. Thirty-five patients were taken home to die, a more likely occurrence if the patient was over 75 years (odds ratio 0.12, 95% CI 0.04-0.34), had children (odds ratio 0.14, 95% CI 0.02-0.79), had Taiwanese as a first language (odds ratio 6.74, 95% CI 3.04-14.93), or was unable to intake orally (odds ratio 2.73, 95% CI 1.26-5.92). CPR was performed in 30 patients, none survived to discharge.

CONCLUSIONS

DNR orders are instituted in a large proportion of dying Chinese cancer patients in a cancer centre, however, the order is seldom signed by the patient personally. This study also illustrates that as many as 20% of dying patients are taken home to die, in accordance with local custom.

A novel podophyllotoxin-derived compound GL331 is more potent than its congener VP-16 in killing refractory cancer cells

PURPOSE

GL331 is a new homolog of VP-16, and has demonstrated more efficacious anti-cancer activity in both the in vitro and in vivo lymphoma systems. To extensively explore GL331's clinical value, we furthermore evaluate the cytotoxicity and apoptosis-inducing activity of GL331 in several human cell lines from cancers that are not normally treated with VP-16.

METHODS

By MTT and clonogenic survival assays, the cytotoxicities of GL331 and VP-16 were evaluated in a variety of cell lines including nasopharyngeal, hepatocellular, gastric, colon, cervical, and neuroblastoma cancer types. Western blot analysis was performed to detect the MDR-1 level in these cell lines. By Annexin V-staining flow cytometry and detection of DNA ladders, the apoptosis-inducing activities of GL331 and VP-16 were also evaluated.

RESULTS

GL331 showed more efficacy than its congener VP-16 in killing cancer cells. The estimated ID50 of GL331 were 2.5 to 17-fold lowerthan those of VP-16. GL331 possessed more cell-killing activity even in MDR-1-overexpressing cell lines such as HCC36 and SW620. Its higher cytotoxicity could be attributed by the elevated ability to induce apoptotic cell death.

CONCLUSION

GL331's overriding drug resistance and higher cancer cell-killing activity suggest its superiority in clinical cancer therapy.

Clinical trials of HCC in Taiwan

Tumors of the liver represent one of the most common malignancies in the world. Little has changed in the past 5 years to alter the statistics. Published census from the Department of Health in Taiwan, 1993, showed that cancer death was 107/100,000 population. Hepatoma is the number one cause of cancer death with 24.05/100,000 population. It increased 11.23% in comparison with last year's survey. About 5,000 people die from hepatoma each year in Taiwan. Both case control studies and cohort studies have shown a strong association between chronic hepatitis B carriage rate and an increased incidence of hepatocellular carcinoma (HCC). Although up to a 200-fold excess incidence of HCC was found in Taiwan, the association of chronic hepatitis B virus in different populations of Southeast Asia who have HCC is somewhat varied. Many treatment modalities for hepatoma have been attempted. Chemotherapy is usually given to patients with metastatic disease or for persistent or recurrent disease. The consensus is that no single drug or combination of drugs given systemically leads to a reproducible response rate of more than 25% or has any effect on survival, or survival beyond that of untreated control. The identification of new, effective chemotherapy drugs and other modality treatments for advanced stage HCC is urgently required. We report here the results regarding response rates, toxicities, and survivals of 14 on-going and finished Phase I, II and III clinical trials on hepatoma. These include chemotherapy and/or biological modifier, radioisotope, hormone, and hepatic infusion. Nine future therapies and gene therapies will also be discussed.

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

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

Percutaneous transhepatic duodenal drainage as an alternative approach in afferent loop obstruction with secondary obstructive jaundice in recurrent gastric cancer

Two cases are reported of chronic, partial afferent loop obstruction with resultant obstructive jaundice in recurrent gastric cancer. The diagnosis was made by characteristic clinical presentations, abdominal computed tomography, and cholescintigraphy. Percutaneous transhepatic duodenal drainage (PTDD) provided effective palliation for both afferent loop obstruction and biliary stasis. We conclude that cholescintigraphy is of value in making the diagnosis of partial afferent loop obstruction and in differentiating the cause of obstructive jaundice in such patients, and PTDD provides palliation for those patients in whom surgical intervention is not feasible.

Ifosfamide-based chemotherapy for previously treated lung cancer patients

BACKGROUND

Ifosfamide-based chemotherapy has already been the basis of three separate clinical trials. In this study, ifosfamide was administered to lung cancer patients who had failed to respond to previous chemotherapy, to assess its response rate and toxicity.

METHODS

From January 1993 to December 1996, 21 patients were treated, including eight patients with small cell lung cancer (SCLC) and 13 with non-small cell lung cancer (NSCLC). Patients who had histocytologically confirmed lung cancer, were previously treated with chemotherapy, had a measurable lesion(s), were younger than 75 years of age, had an Eastern Cooperative Oncology Group performance status of 0-3 and adequate marrow, renal and liver function were eligible for inclusion in this study. For SCLC patients, ifosfamide 2.4 g/m2 intravenous (i.v.) infusion was given over 30 minutes on days 1-3 every four weeks. For NSCLC two regimens were used: IFL (ifosfamide 2 g/m2, 5-fluorouracil (FU) 600 mg/m2 and leucovorin 50 mg/m2 i.v. infusion on days 1-3 every four weeks) and LIFE (leucovorin 50 mg/m2, ifosfamide 1 g/m2, 5-FU 400 mg/m2 and epirubicin 12 mg/m2 i.v. infusion on days 1-3 every four weeks). For NSCLC patients, IFL was used for the first two years of treatment and LIFE was used in the last two treatment years. All patients were evaluated for treatment response and toxicity.

RESULTS

The major toxic effect, myelosuppression (grade 3 or 4 leukopenia), occurred in 62.5% of SCLC patients and 23.1% of NSCLC patients during treatment, and in 62.5% and 10% of SCLC and NSCLC patients, respectively, throughout the course. Only one SCLC and one NSCLC patient experienced febrile neutropenia. One toxic death, attributed to febrile neutropenia, was documented in a patient with SCLC. Alopecia was ubiquitous. Other toxicities were uncommon and mild. The overall response rate was 50% in SCLC and 7.7% in NSCLC. The median time to disease progression was 61 days in SCLC and 47 days in NSCLC. Median survival was 172 days in SCLC and 173 days in NSCLC.

CONCLUSIONS

The study results suggest that ifosfamide chemotherapy is active with an acceptable toxicity profile in previously treated SCLC patients. However, it lacks efficacy in NSCLC patients who have been previously treated.

Continuous infusion cisplatin and etoposide chemotherapy for cancer of unknown primary site (CUPS) in Taiwan, a region with a high prevalence of endemic viral infections

BACKGROUND

To evaluate the efficacy and toxicity of cisplatin/etoposide continuous infusion chemotherapy for cancer of unknown primary site in Taiwan, a region with a high prevalence of endemic viral infections.

METHOD

Between April 1994 and February 1996, 20 patients with a diagnosis of CUPS were treated, including 15 males and five females, of average age 63.3 years (range 41-83 years). Continuous intravenous infusion of etoposide 80 mg/m2 and cisplatin 25 mg/m2 was given for 3 days every 3 weeks. Pretreatment tumor marker and viral serology studies were performed for baseline evaluation. Nearly two-thirds of the patients had poorly differentiated carcinoma. The average number of metastatic sites was 2.65 (range 1-4), with liver and lymph node involvement predominating.

RESULTS

The overall response rate was 25% (95% CI 17.7-32.3%); 30.7% for poorly differentiated cancers and 25% for well differentiated cancers. Median survival was 4 months (range 1-12 months), 4.8 months for patients attaining partial response. Toxicity was moderate, grade 3 and 4 neutropenia occurred in 55% and grade 3 and 4 thrombocytopenia in 40%; other toxicities were mild. CA125 and CA199 were elevated in more than 50% of patients. Viral serology studies were not significantly different from those of the indigenous population.

CONCLUSION

Etoposide and cisplatin combination chemotherapy has modest activity in patients with extensive CUPS and, at the schedule and dosage given, it is associated with moderate toxicity.

S- and G2-phase cell cycle arrests and apoptosis induced by ganciclovir in murine melanoma cells transduced with herpes simplex virus thymidine kinase

Mechanism of cell killing by transfer of Herpes simplex virus type-1 thymidine kinase (HSVtk) and subsequent ganciclovir (GCV) treatment was examined in B16F10 murine melanoma model. While parental B16F10 melanoma cells were resistant to GCV at 100 microM or higher, HSVtk-transduced B16F10 melanoma cell clones became susceptible to GCV with IC50 of 0.1 to 0.3 microM. By means of various parameters including characteristic morphological changes, in situ DNA end-labeling, DNA ladder pattern, flow cytometric detection of sub-G1 DNA content, and annexin V binding of inverted cell surface phosphatidylserine, apoptosis was shown to be associated with the cell killing of ganciclovir on HSVtk-transduced melanoma B16F10 cells. Kinetic analysis showed that the signs of apoptosis were observed not until 60 h of continued GCV treatment and preceded first by a rise in p53 protein level in 12 h and then by S-phase/G2-phase cell cycle arrest associated with corresponding increases in the level of cyclin B1 protein but no apparent change in protein level of Bax or Cdc2. These results suggest that apoptosis occurred as a result of ganciclovir-induced cell cycle arrests rather than direct chemical effect on HSVtk-transduced B16F10 melanoma cells.