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Brigette B Y Ma,
Vivian W Y Lui,
Fan Fong Poon,
S C Cesar Wong,
Ka Fai To,
Elaine Wong,
Honglin Chen,
Kwok Wai Lo,
Qian Tao,
Anthony T C Chan,
Margaret Heung Ling Ng,
Suk Hang Cheng
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ABSTRACT: This study evaluated the preclinical activity and molecular predictors of response to gefitinib (Iressa(R), Astra Zeneca Inc, UK) in nasopharyngeal carcinoma (NPC). The activity of gefitinib was evaluated in four human NPC cell lines--HK1, HONE-1, CNE2, C666-1. A representative gefitinib-sensitive (HK1, IC(50) = 250 nM) and gefitinib-resistant cell line (HONE-1, IC(50) > 15 microM) were selected and compared for expression of epidermal growth factor receptor (EGFR) and related ligands, and activation of downstream proteins. Gefitinib induced G1 cycle arrest, apoptosis and inhibited cell invasion more significantly in HK1 than HONE-1 cells. HK1 expressed higher levels of p-EGFR, lower p-AKT and phospho-signal transducer and activator of transcription 3 (p-STAT3) than other cell lines. EGFR gene was found to be amplified in HK1. Gefitinib at IC(50) concentrations significantly suppressed EGF-induced activation of p-EGFR, phospho-mitogen-activated protein kinase (p-MAPK) and p-STAT3, but p-AKT showed persistent activation in HK1 and HONE-1 cells. There was no difference in EGFR-ligand expression between the 4 NPC cell lines. In NPC samples derived from non-responders to gefitinib, 50% and 60% showed cytoplasmic and nuclear pi-EGFR expression, respectively, and 33% showed p-AKT expression. EGFR or KRAS mutations were not detected. This study suggests that most NPC cell lines are intrinsically resistant to gefitinib (except HK1 cells), and further studies are needed to confirm whether EGFR gene amplification and persistent AKT activation may influence response to gefitinib in NPC.
Investigational New Drugs 09/2009; 28(3):326-33. · 3.36 Impact Factor
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ABSTRACT: Phosphorylated (pi-) protein kinase B (AKT) is commonly expressed in nasopharyngeal carcinoma (NPC) cell lines and tissues, suggesting the involvement of AKT-mammalian target of rapamycin (mTOR) signaling in NPC carcinogenesis. This study evaluated the activity of an mTOR inhibitor, RAD001 (Everolimus, Novartis Pharma AG, Switzerland), in 5 NPC cell lines (HK1, HONE-1, CNE-1, CNE-2, C666-1), 2 cisplatin-resistant NPC cell lines and their respective parental cell lines (HK1-LMP1, HONE-1-EBV). RAD001 inhibited cell growth in a dose-dependent manner at nanomolar concentrations in all cell lines. HONE-1 was most sensitive to RAD001 (IC(50) = 0.63 nM, 60% maximal inhibition), while Het-1A (a normal esophageal epithelial cell line) was relatively resistant. No consistent relationship between sensitivity to RAD001 and basal expression of pi-mTOR and pi-p70S6 Kinase-1 (p70S6K) was found. Exposure to RAD001 at picomolar concentrations for 48 h resulted in reduction of pi-mTOR and pi-p70S6K1 expression, but increase in pi-AKT (Ser473) expression in HONE-1 and CNE-1 cell lines. RAD001 significantly induced apoptosis in HONE-1 cells, but has no effect on cell cycle progression. RAD001 exerted an additive to synergistic effect on cisplatin-induced growth inhibition in CNE-1 and HONE-1 cells, and could inhibit the growth of both cisplatin-resistant and cisplatin-sensitive NPC cell lines. In summary, combination of RAD001 and cisplatin maybe a useful therapeutic strategy in NPC. AKT upregulation following RAD001 treatment suggests the presence of a feedback loop on AKT signaling in NPC which warrants further investigation.
Investigational New Drugs 06/2009; 28(4):413-20. · 3.36 Impact Factor
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IDrugs: the investigational drugs journal 03/2009; 12(2):69-72. · 2.28 Impact Factor
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ABSTRACT: The activity of the histone deacetylase inhibitor PXD101 was investigated in three hepatocellular carcinoma (HCC) cell lines. PXD101 was found to inhibit cell growth at a dose-dependent manner and induce histone acetylation in PLC/PRF/5, Hep3B and HepG2 cells. In PLC/PRF/5 and Hep3B cells which express hepatitis B-related genes (HBx, HBc and HBc), treatment with PXD101 resulted in apoptosis without a significant effect on viral gene expression. Exposure to PXD101 for up to 48 h had varying effects on the expression of 12 cellular genes with tumor suppressor functions, including p21, SOCS1, CMTM5, RASAL1, DLEC1, SFRP (-1, -2, -4 and -5), ADAMTS (-8 and -9). This study provided the basis for a phase II clinical trial of PXD101 in inoperable hepatitis-B associated HCC.
Investigational New Drugs 02/2009; 28(2):107-14. · 3.36 Impact Factor
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Brigette Ma,
Edwin P Hui,
Ann King,
K F To,
Frankie Mo,
Sing F Leung,
Michael Kam,
Y M Dennis Lo,
Benny Zee,
Tony Mok,
Anil Ahuja,
Anthony T C Chan
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ABSTRACT: The epidermal growth factor receptor (EGFR) is commonly overexpressed in nasopharyngeal carcinoma (NPC) and gefitinib inhibits NPC growth in vitro.
Patients who progressed after prior platinum-based chemotherapy for recurrent NPC were given gefitinib orally at 500 mg/day at a 28-day cycle. Plasma Epstein-Barr virus (pEBV) DNA levels were obtained at specific intervals.
Sixteen patients enrolled and 15 were evaluable for response. The median age was 49 years (range 34-64 years), and most patients were males with metastatic NPC. No objective response was seen and three patients had stable disease (SD) for 2.8 to 8.5 months. Radiological progression of disease coincided with rising levels of pEBV DNA in most patients, while the level of a patient with the longest duration of SD fell to an undetectable level at study completion. The mean time to progression and overall survival was 2.7 (standard error, SE +/- 0.5 months) and 12 months (SE +/- 1.7 months), respectively. No unexpected drug-related toxicities were seen. The study was prematurely terminated because there was insufficient activity to warrant progression to the second stage of accrual.
This study found limited activity of gefitinib in recurrent NPC. Further evaluation of pEBV DNA as a biomarker of response in clinical trials of target-based agents is warranted.
Cancer Chemotherapy and Pharmacology 07/2008; 62(1):59-64. · 2.83 Impact Factor
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Brigette Ma,
Boon Cher Goh,
Eng Huat Tan,
Kwok Chi Lam,
Ross Soo,
Swan Swan Leong,
Ling Zhi Wang,
Frankie Mo,
Anthony T C Chan,
Benny Zee,
Tony Mok
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ABSTRACT: We tested the hypothesis that 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (3-AP, Triapine) may enhance response to re-treatment with gemcitabine by enhancing intracellular uptake of gemcitabine in a phase II study.
Patients who had prior exposure to gemcitabine as a first-line treatment of advanced non-small-cell lung cancer (NSCLC) were given weekly infusions of 3-AP and gemcitabine for 3 weeks followed by 1 week of rest, repeated every 28 days. Plasma and peripheral blood mononuclear cells (PBMCs) were collected to evaluate the effect of 3-AP on pharmacokinetics and intracellular uptake of gemcitabine.
Twelve patients were treated with a median of two treatment cycles without objective response, hence the study was terminated at interim analysis. Four patients had stable disease and the median time to progression was 3 months (95% confidence interval, CI: 1.7 to 9.1 months). Grade 3 toxicities included neutropenia (two patients), hypoxia (three patients) and dyspnea (one patient). Four patients developed reversible symptomatic methemoglobinemia during 3-AP infusion, with mild to moderately elevated methemoglobin levels that ranged from 7.8 to 17.6% of the total hemoglobin concentration. Limited pharmacokinetic data did not suggest any clinically relevant pharmacological influence of 3-AP on gemcitabine.
3-AP did not enhance clinical response to gemcitabine in this cohort of patients with prior exposure to gemcitabine for advanced NSCLC. Further development of 3-AP in lung cancer is challenged by its potential of causing methemoglobinemia and hypoxia, which could be problematic in patients with compromised pulmonary reserves.
Investigational New Drugs 05/2008; 26(2):169-73. · 3.36 Impact Factor
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ABSTRACT: Abstract
Background
Circulating plasma Epstein Barr Virus DNA (EBV-DNA) is a sensitive and specific marker of nasopharyngeal carcinoma (NPC). The mainstay of treatment of metastatic NPC is systemic chemotherapy and resection for solitary metastasis. Despite high response rate to chemotherapy, complete remission is uncommonly seen.
Case Presentation
We report a case of recurrent metastatic NPC in a 43-year-old man, who achieved complete remission three times with chemotherapy and surgery. Serial plasma EBV-DNA levels were measured during the course of disease. The patient had three episodes of recurrences of NPC manifested as distant metastasis. Both time, rise in the plasma EBV-DNA level preceded detection of recurrences by imaging. Following systemic chemotherapy, he achieved complete remission each time, of which was confirmed by 18-flourodeoxyglucose positron emission tomography and hepatectomy pathology. The plasma EBV-DNA level dropped to zero copy/ml at the time of each remission.
Conclusion
This case highlights the high chemosensitivity of NPC by illustrating a rare occurrence of complete response of metastatic NPC to chemotherapy. This case also underscores the usefulness of EBV-DNA as a useful tool in monitoring NPC by its ability to detect early recurrence and excellent correlation with treatment response.
BMC Cancer. 01/2006;
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Onkologie 11/2005; 28 Suppl 4:18-24. · 0.87 Impact Factor
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Winnie Yeo,
Tony S Mok,
Benny Zee,
Thomas W T Leung,
Paul B S Lai,
Wan Y Lau,
Jane Koh,
Frankie K F Mo,
Simon C H Yu,
Anthony T Chan,
Pun Hui, Brigette Ma,
Kwok C Lam,
Wing M Ho,
Herman T Wong,
Amanda Tang,
Philip J Johnson
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ABSTRACT: Single-agent doxorubicin has been widely used to treat unresectable hepatocellular carcinoma (HCC), but the response rate is low (< 20%) and there is no convincing evidence for improved survival. Cisplatin, interferon, doxorubicin, and fluorouracil (PIAF) used in combination, by contrast, has shown promise in a phase II study. We compared doxorubicin to PIAF in patients with unresectable HCC in a phase III trial.
Patients with histologically confirmed unresectable HCC were randomly assigned to receive either doxorubicin or PIAF every 3 weeks, for up to six cycles. The primary endpoint was overall survival, and secondary endpoints were response rate and toxicity. Survival differences were calculated using the Kaplan-Meier method. Treatment groups were compared for differences in the incidence of adverse events using chi-square tests. All statistical tests were two-sided.
The median survival of the doxorubicin and PIAF groups was 6.83 months (95% confidence [CI] = 4.80 to 9.56) and 8.67 months (95% CI = 6.36 to 12.00), respectively (P = 0.83). The hazard ratio for death from any cause in the PIAF compared with the doxorubicin groups was 0.97 (95% CI = 0.71 to 1.32). Eighty-six of the 94 patients receiving doxorubicin and 91 of the 94 receiving PIAF were assessable for response. The overall response rates in the doxorubicin and PIAF groups were 10.5% (95% CI = 3.9% to 16.9%) and 20.9% (95% CI = 12.5% to 29.2%), respectively. Neutropenia, thrombocytopenia, and hypokalemia were statistically significantly more common in patients treated with PIAF than in patients treated with doxorubicin.
Although patients on PIAF had a higher overall response rate and better survival than patients on doxorubicin, the differences were not statistically significant. PIAF was also associated with increased treatment-related toxicity. The prognosis of patients with unresectable HCC remains poor.
CancerSpectrum Knowledge Environment 10/2005; 97(20):1532-8. · 14.07 Impact Factor
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ABSTRACT: Patients with International Union Against Cancer (UICC) Stage I-II nasopharyngeal carcinoma (NPC) appear to have a relatively favorable prognosis and generally are excluded from trials of combined modality treatment. More recently, plasma/serum cell-free Epstein-Barr virus (EBV) DNA has been shown to be measurable in the majority of NPC patients at the time of diagnosis, and appears to have prognostic significance. However, within Stage I-II disease, in which failure events are infrequent, the prognostic impact of the pretreatment EBV DNA level has not been addressed to our knowledge. This issue has management implications because different therapeutic strategies currently are employed for patients with good-risk and those with poor-risk NPC.
A cohort of 90 patients with UICC Stage I-II NPC (World Health Organization Grade 2/3 histology) had their pretherapy plasma/serum EBV DNA levels determined by a quantitative polymerase chain reaction assay and correlated with the probability of posttherapy failure. All patients received radiation therapy only, except for three patients who also received concurrent chemotherapy. Kaplan-Meier plots of the probability of locoregional failure, distant failure, and cancer-specific survival were compared with reference to clinical stage and EBV DNA levels.
With a median follow-up time of 45 months, 12 patients and 7 patients, respectively, had developed locoregional and distant failures, including 2 patients with both local and distant failures. Patients with distant failure had significantly higher pretherapy EBV DNA levels than those without failure (a median of 13,219 copies/mL [interquatile-range, 274,635 copies/mL] vs. a median of 423 copies/mL [interquatile-range, 2753 copies/mL]). The probability of distant failure was significantly higher in patients with high (>4000 copies/mL plasma) compared with low EBV DNA levels (P=0.0001, log-rank test) and for Stage IIB disease compared with Stage I and Stage IIA disease combined (P=0.0149, log-rank test), but was not significantly different between patients with Stage II and those with Stage I disease. The risks of locoregional failure were not significantly different between patients with high and those with low EBV DNA levels, and also was not significantly different between clinical substages. Approximately 35% of patients with Stage IIB disease were in the at-risk group for distant failure, as identified by high EBV DNA levels.
Within a group of patients with UICC Stage I-II NPC, the pretherapy plasma EBV DNA level was found to identify a poor-risk group with a probability of distant failure similar to that of patients with advanced stage disease. This group of patients may warrant management considerations currently applicable only to cases of Stage III-IV disease. The prognostic significance of designating Stage IIB disease as per the 1997 UICC staging was confirmed, although the pretherapy EBV DNA level appears to be a more powerful prognostic discriminator in patients with early-stage NPC.
Cancer 07/2003; 98(2):288-91. · 4.77 Impact Factor
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ABSTRACT: A cohort of 85 Chinese breast cancer patients who received adjuvant chemotherapy with doxorubicin and cyclophosphamide was found to have a significantly higher incidence of grade 3 (n=44, 52%) and grade 4 (n=21, 25%) neutropenia when compared with an historic Western cohort. Also noted was a higher incidence of hepatotoxicity (n=8, 9%). When compared to Caucasian patients, the higher myelotoxicity in our patients may be related to ethnic variation in susceptibility to chemotherapy-related toxicity, lower body mass index with higher percentage of body fat composition, and the popular practice of concurrent alternative medicine during chemotherapy. The higher incidence of hepatoxicity was possibly associated with endemic chronic hepatitis B infection in this geographical area.
Radiotherapy and Oncology 03/2002; 62(2):185-9. · 5.58 Impact Factor
