Report of rare genotypes of Acanthamoeba from soil source of the Payeh Maga Highland forest, North-eastern Sarawak, Malaysia

Pathogenic Acanthamoeba species are the causative agents of Acanthamoeba keratitis and granulomatous amoebic encephalitis. Members of this amoeba genus are ubiquitous in the environments. In Malaysia, most environmental studies performed to date have targeted the detection and characterisation of Acanthamoeba sp. in different water sources, dust and soil samples collected near human habitats. However, no local study has yet to examine these amoebae in a forest, an isolated terrestrial environment, where human activity is relatively scarce. Further, there are also limited studies to investigate the same globally. The current study reported the isolation, morphological and genotypic characterisations of eleven Acanthamoeba sp. isolated from soils of the Payeh Maga Highland forest, Sarawak, Malaysia. Morphological analysis revealed that nine isolates belonged to Group II, whereas two isolates belonged to Group III as defined by the criteria of Pussard and Pons. The phylogenetic analysis based on complete 18S rRNA gene sequences showed that the isolates belonged to the rare T1 (six isolates), T6 (two isolates) and T13 (three isolates) genotypes. To the best of our knowledge, this is the first report about the detection of T6 Acanthamoeba sp. in this country. Overall, the current findings have enriched the knowledge pertaining to the occurrence, morphological and genotypic characteristics of Acanthamoeba sp. in an isolated terrestrial environment of Malaysia.

A phase Ib study of selumetinib (AZD6244, ARRY-142886) in combination with sorafenib in advanced hepatocellular carcinoma (HCC)

BACKGROUND

Treatment with sorafenib, although associated with inhibition of tumour growth and angiogenesis in in vivo studies, leads to up-regulation of pERK. The addition of MEK inhibition could potentially abrogate this effect and potentiate anti-tumour activity. This phase I study investigated the maximum tolerated dose (MTD), safety, tolerability, pharmacokinetics (PK) and biomarker correlates of selumetinib combined with sorafenib in patients with advanced hepatocellular carcinoma (HCC).

METHODS

Patients with Child-Pugh (CP) score ≤7 were treated with 400 mg twice daily of sorafenib with escalating doses of selumetinib in a 3 + 3 study design. The dose-limiting toxicity (DLT) evaluation period was 28 days. PK of selumetinib was determined. Angiogenic effect was evaluated with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

RESULTS

Twenty-seven patients of Asian ethnicity were enrolled. The MTD was selumetinib 75 mg daily with sorafenib 400 mg twice daily. DLT included grade 3 transaminitis, diarrhoea and fatigue. Most common treatment-related adverse events at MTD (all grades) were diarrhoea (85%), rash (59%), hypertension (44%), fatigue (30%), anorexia (22%) and hand-foot syndrome (22%). Four patients (15%) had PR and 13 (48%) had SD. PR or SD was observed for ≥6 months in seven patients. The median overall survival was 14.4 months. Selumetinib exposures in combination with sorafenib were comparable to other monotherapy studies. A reduction in permeability-surface area product noted in DCE-MRI with treatment correlated with worse survival outcomes.

CONCLUSION

The MTD of selumetinib was 75 mg daily when combined with sorafenib 400 mg twice a day in CP ≤7 HCC. Acceptable adverse events and encouraging anti-tumour activity warrant further evaluation. DCE-MRI findings deserve prospective evaluation.

CLINICALTRIALSGOV IDENTIFIER

NCT01029418.

A Phase 1 dose-finding and pharmacodynamic study of rapamycin in combination with bevacizumab in patients with unresectable hepatocellular carcinoma

BACKGROUND & AIMS

Preclinical studies have demonstrated the additive effect of rapamycin with bevacizumab for hepatocellular carcinoma treatment. We conducted a Phase 1 study to evaluate the safety and pharmacokinetics of the combination in patients with hepatocellular carcinoma.

METHODS

Adult participants with advanced hepatocellular carcinoma received intravenous bevacizumab (5mg/kg every 14 days) and oral rapamycin (1-6 mg/day; 3+3 dose escalation design). Computed tomography assessed tumour response and treatment safety. Pharmacokinetics assessment established rapamycin blood concentrations pre- and post-dose. Dynamic contrast-enhanced computed tomography analysed the tumour region for blood flow, permeability surface area product, fractional intravascular blood volume and extracellular-extravascular volume.

RESULTS

Twenty-four participants were treated. There were two dose limiting toxicities with rapamycin 5mg: grade 3 thrombocytopenia and grade 3 mucositis. The maximally tolerated dose of rapamycin was 4 mg. Adverse events (grade 1-2) included hyperglycaemia (83%), thrombocytopenia (75%), fatigue (46%), mucositis (46%), anorexia (42%), diarrhoea (33%) and proteinuria (12.5%). Of 20 evaluable participants, one reached complete response that lasted 4.5 months, two reached partial response, 14 reached stable disease and three had progressive disease. Median overall survival was 9.4 months; progression-free survival was 5.5 months. Dose level and steady state area under the concentration time curve for hour zero to infinity of rapamycin correlated inversely with blood flow rate and change in permeability-surface area. After 22 days of treatment, there were significant reductions from baseline in blood flow rate, permeability-surface area and fractional intracellular blood volume.

CONCLUSIONS

The recommended Phase 2 dose of rapamycin is 4 mg in combination with bevacizumab. Evidence of anti-vascular activity was observed together with promising clinical activity.

Comparing the efficacy of sunitinib with sorafenib in xenograft models of human hepatocellular carcinoma: mechanistic explanation

Hepatocellular carcinoma (HCC) is the fifth most common and third deadliest malignancy. Sorafenib has demonstrated 44% survival advantage over placebo and has emerged as a standard of care in advanced HCC. The therapeutic effects of sorafenib are however transient and hence additional treatment options are warranted. In this study, we aimed to compare the efficacy of sunitinib relative to sorafenib, two potent inhibitors of protein tyrosine kinases involved in tumor growth, metastasis, or angiogenesis. We reported that sorafenib and sunitinib suppressed tumor growth, angiogenesis, cell proliferation, and induced apoptosis in both orthotopic and ectopic models of HCC. However, the antitumor effect of 50 mg/kg sorafenib was greater than that of 40 mg/kg sunitinib. Sorafenib inhibited p-eIF4E Ser209, p-p38 Thr180/Tyr182 and reduced survivin expression. This was not seen with sunitinib. In addition, the antitumor and apoptotic effects of sorafenib, which are associated with upregulation of fast migrating Bim and ASK1 and downregulation of survivin, were greater than that of sunitinib. These observations explained in part the apparent superior anti-tumor activity of sorafenib compared to sunitinib. In conclusion, sunitinib demonstrated an inferior anti-tumor activity compared to sorafenib in ectopic and orthotopic models of human HCC. It remains to be seen whether such observations would be recapitulated in humans.

A phase II study evaluating the safety and efficacy of an adenovirus-ΔLMP1-LMP2 transduced dendritic cell vaccine in patients with advanced metastatic nasopharyngeal carcinoma

BACKGROUND

Individuals with metastatic Epstein-Barr virus (EBV)-positive nasopharyngeal carcinoma (NPC) continue to have poor outcomes. To evaluate the ability of a dendritic cell (DC) vaccine to target subdominant EBV antigens LMP1 and LMP2 expressed by NPC cells, we vaccinated patients using autologous DCs transduced with an adenovirus encoding a truncated LMP1 (ΔLMP1) and full-length LMP2 (Ad-ΔLMP1-LMP2).

MATERIALS AND METHODS

Sixteen subjects with metastatic NPC received Ad-ΔLMP1-LMP2 DC vaccines i.d. biweekly for up to five doses. Toxicity, immune responses and clinical responses were determined.

RESULTS

Most patients had extensive disease, with a median of three visceral sites of involvement (range 1-7). No significant toxicity was observed. Ad-ΔLMP1-LMP2 DCs induced delayed type hypersensitivity responses in 9 out of 12 patients, but although these DCs activated LMP1/2-specific T cells in vitro, no such increase in the frequency of peripheral LMP1/2-specific T cells was detected. Three patients had clinical responses including one with partial response (for 7½ months) and two with stable disease (for 6½ and 7½ months).

CONCLUSIONS

Ad-ΔLMP1-LMP2 transduced DCs can be successfully generated and safely administered to patients with advanced NPC. Since efficacy was limited, future studies should focus on DC vaccines with greater potency administered to subjects with less tumor burden.

Phase I and pharmacodynamic study of an orally administered novel inhibitor of histone deacetylases, SB939, in patients with refractory solid malignancies

BACKGROUND

The objective of this study was to assess the safety, maximum tolerated dose (MTD), pharmacokinetics, pharmacodynamics, and preliminary efficacy of SB939, a novel histone deacetylase (HDAC) inhibitor, in patients with advanced solid malignancies.

PATIENTS AND METHODS

Dose-escalating cohorts of three to six patients received SB939 orally thrice weekly for 3 weeks in a 4-week cycle. Acetylated histone H3 (acH3) was measured in peripheral blood mononuclear cells (PBMCs).

RESULTS

Thirty patients treated at one of five doses (10-80 mg/day) received 79 cycles of SB939 (range, 1-12 cycles). Dose-limiting toxic effects were fatigue, hypokalemia, troponin T elevation, and QTc prolongation. Peak plasma concentration (C(max)) and area under the concentration-time curve extrapolated to infinity increased dose proportionally. The MTD of SB939 was 80 mg/day. The mean elimination half-life and oral clearance of SB939 were 7.2 ± 0.6 h and 53.0 ± 8.5 l/h, respectively, with no substantial accumulation on day 15. An increase in acH3 was observed at hour 3 and correlated with dose and C(max). Stable disease was seen in several tumor types treated at ≥40 mg. HDAC inhibition was consistently observed at 60 mg, the recommended dose.

CONCLUSIONS

SB939 can be safely administered at the recommended dose and reaches plasma levels that strongly inhibit HDAC in PBMCs. These data support further efficacy studies of SB939.

Graft-vs-tumor effect in patients with advanced nasopharyngeal cancer treated with nonmyeloablative allogeneic PBSC transplantation

While nonmyeloablative peripheral blood stem cell transplantation (NST) has shown efficacy against several solid tumors, it is untested in nasopharyngeal cancer (NPC). In a phase II clinical trial, 21 patients with pretreated metastatic NPC underwent NST with sibling PBSC allografts, using CY conditioning, thymic irradiation and in vivo T-cell depletion with thymoglobulin. Stable lymphohematopoietic chimerism was achieved in most patients and prophylactic CYA was tapered at a median of day +30. Seven patients (33%) showed partial response and three (14%) achieved stable disease. Four patients were alive at 2 years and three showed prolonged disease control of 344, 525 and 550 days. With a median follow-up of 209 (4-1147) days, the median PFS was 100 days (95% confidence interval (CI), 66-128 days), and median OS was 209 days (95% CI, 128-236 days). Patients with chronic GVHD had better survival-median OS 426 days (95% CI, 194-NE days) vs 143 days (95% CI, 114-226 days) (P=0.010). Thus, NST may induce meaningful clinical responses in patients with advanced NPC.

Efficacy and tolerability of bevacizumab plus capecitabine as first-line therapy in patients with advanced hepatocellular carcinoma

Background:

Molecularly targeted agents with anti-angiogenic activity, including bevacizumab, have demonstrated clinical activity in patients with advanced/metastatic hepatocellular carcinoma (HCC). This multicentre phase II study involving patients from several Asian countries sought to evaluate the safety and efficacy of bevacizumab plus capecitabine in this population.

Methods:

Histologically proven/clinically diagnosed advanced HCC patients received bevacizumab 7.5 mg kg^–1 on day 1 and capecitabine 800 mg m^–2 twice daily on days 1–14 every 3 weeks as first-line therapy.

Results:

A total of 45 patients were enrolled; 44 (96%) had extrahepatic metastasis and/or major vessel invasion and 30 (67%) had hepatitis B. No grade 3/4 haematological toxicity occurred. Treatment-related grade 3/4 non-haematological toxicities included diarrhoea (n=2, 4%), nausea/vomiting (n=1, 2%), gastrointestinal bleeding (n=4, 9%) and hand–foot syndrome (n=4, 9%). The overall response rate (RECIST) was 9% and the disease control rate was 52%. Overall, median progression-free survival (PFS) and overall survival (OS) were 2.7 and 5.9 months, respectively. Median PFS and OS were 3.6 and 8.2 months, respectively, for Cancer of the Liver Italian Programme (CLIP) score ⩽3 patients, and 1.4 and 3.3 months, respectively, for CLIP score 4 patients.

Conclusion:

The bevacizumab–capecitabine combination shows good tolerability and modest anti-tumour activity in patients with advanced HCC.

Efficacy and tolerability of bevacizumab plus capecitabine as first-line therapy in patients with advanced hepatocellular carcinoma

BACKGROUND

Molecularly targeted agents with anti-angiogenic activity, including bevacizumab, have demonstrated clinical activity in patients with advanced/metastatic hepatocellular carcinoma (HCC). This multicentre phase II study involving patients from several Asian countries sought to evaluate the safety and efficacy of bevacizumab plus capecitabine in this population.

METHODS

Histologically proven/clinically diagnosed advanced HCC patients received bevacizumab 7.5 mg kg(-1) on day 1 and capecitabine 800 mg m(-2) twice daily on days 1-14 every 3 weeks as first-line therapy.

RESULTS

A total of 45 patients were enrolled; 44 (96%) had extrahepatic metastasis and/or major vessel invasion and 30 (67%) had hepatitis B. No grade 3/4 haematological toxicity occurred. Treatment-related grade 3/4 non-haematological toxicities included diarrhoea (n=2, 4%), nausea/vomiting (n=1, 2%), gastrointestinal bleeding (n=4, 9%) and hand-foot syndrome (n=4, 9%). The overall response rate (RECIST) was 9% and the disease control rate was 52%. Overall, median progression-free survival (PFS) and overall survival (OS) were 2.7 and 5.9 months, respectively. Median PFS and OS were 3.6 and 8.2 months, respectively, for Cancer of the Liver Italian Programme (CLIP) score < or =3 patients, and 1.4 and 3.3 months, respectively, for CLIP score 4 patients.

CONCLUSION

The bevacizumab-capecitabine combination shows good tolerability and modest anti-tumour activity in patients with advanced HCC.

Sunitinib (SUTENT, SU11248) suppresses tumor growth and induces apoptosis in xenograft models of human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common and third deadliest primary neoplasm. Since HCC is a particularly vascular solid tumor, we determined the antitumor and antiangiogenic activities of sunitinib malate, a potent inhibitor of two receptors involved in angiogenesis - vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR). In the present study, we reported that treatment of HepG2 and SK-Hep-1 cells with sunitinib led to growth inhibition and apoptosis in a dose-dependent fashion. Sunitinib inhibited phosphorylation of VEGFR-2 at Tyr951 and PDGFR-beta at Tyr1021 both in vitro and in vivo. Sunitinib also suppressed tumor growth of five patient-derived xenografts. Sunitinib-induced tumor growth inhibition was associated with increased apoptosis, reduced microvessel density and inhibition of cell proliferation. This study provides a strong rationale for further clinical investigation of sunitinib in patients with hepatocellular carcinoma.

Two case reports of metastases from colon carcinoma to the thyroid

INTRODUCTION

Secondary malignancy of the thyroid gland is uncommon, but it is a problem requiring ongoing recognition. As it is more common than primary thyroid malignancy, metastatic disease involving the thyroid gland should be actively excluded in a patient with enlarging or abnormal thyroid gland and a previously known primary tumour.

CLINICAL PICTURE

We report 2 cases of primary colon carcinoma with metastasis to the thyroid gland that mimicked thyroid anaplastic carcinoma. In both cases, airway compromise was evident.

TREATMENT AND OUTCOME

Emergency tracheostomy was necessary in the first case with subsequent oxaliplatin-based chemotherapy providing palliation of symptom of breathlessness, with significant reduction in size of thyroidal metastasis. Palliative thyroidectomy relieved airway compromise in the second case.

CONCLUSION

Our case report highlights the importance of early recognition of thyroidal metastases from a colonic primary as life-threatening airway compromise may otherwise rapidly ensue.

Targeting dendritic cells to enhance DNA vaccine potency

DNA vaccination that can induce both cellular and humoral immune responses has become an attractive immunization strategy against cancer and infection. Dendritic cells (DCs) play a critical role in the induction of immune responses by DNA vaccination. However, a major problem of DNA vaccination is its limited potency, because only a very limited fraction of injected DNA molecules are taken up by DCS: In this study, we describe a novel DNA vaccination strategy to enhance uptake and presentation of antigens by DCS: Specifically, we developed a DNA vaccine based upon expression of a model hepatitis B virus (HBV) e antigen fused to an IgG Fc fragment. After vaccination, the DNA are taken up by cells that produce and secrete the antigen-Fc fusion proteins. The secreted fusion proteins, in addition to inducing B cells, are efficiently captured and processed by DCs via receptor-mediated endocytosis and then presented to the MHC class II and as -I (cross-priming). The results of this study demonstrate that broad enhancement of antigen-specific CD4+ helper, CD8+ cytotoxic T-cell, and B-cell responses can be achieved by this DNA vaccination strategy. Thus, the strategy capable of inducing all arms of the adaptive immunity may provide a novel, generic design for the development of therapeutic and preventive DNA vaccines.

Intentional induction of mixed chimerism and achievement of antitumor responses after nonmyeloablative conditioning therapy and HLA-matched donor bone marrow transplantation for refractory hematologic malignancies

Mixed lymphohematopoietic chimerism can be induced in mice with bone marrow transplantation (BMT) after a nonmyeloablative preparative regimen that includes cyclophosphamide, anti-T-cell antibody therapy, and thymic irradiation. These mixed chimeras are resistant to the induction of graft-versus-host disease (GVHD) after delayed donor leukocyte infusions (DLIs), despite a potent lymphohematopoietic graft-versus-host reaction that converts the mixed chimeric state to a full donor one. Based on this animal model, we initiated a trial of nonmyeloablative therapy with HLA-matched or -mismatched donor BMT and DLI for refractory hematologic malignancies. Twenty-one of 36 patients enrolled in this trial received a genotypically (n = 20) or phenotypically (n = 1) HLA-matched donor transplant; results reported here are for those patients only. Preparative therapy consisted of cyclophosphamide in doses of 150 to 200 mg/kg; peritransplant antithymocyte globulin; thymic irradiation (in patients who had not received previous mediastinal radiation therapy); and cyclosporine. Eighteen of 20 evaluable patients developed persistent mixed lymphohematopoietic chimerism as defined by >1% donor peripheral white blood cells until at least day 35 posttransplantation. Ten patients received prophylactic DLI beginning 5 to 6 weeks after BMT for conversion of mixed chimerism to full donor hematopoiesis and to optimize a graft-versus-leukemia effect. Fourteen of 20 evaluable patients (70%) achieved an antitumor response; 8 of these responses were complete, and 6 were partial. Of the 8 evaluable patients who received prophylactic DLI, 6 showed conversion to full donor chimerism. Five of the 9 evaluable patients (56%) who received prophylactic DLI achieved a complete response, compared with 3 of 11 patients (27%) who did not receive prophylactic DLI. Currently 11 patients are alive, and 7 of these are free of disease progression at a median follow-up time of 445 days (range, 105-548 days) posttransplantation. Transplantation-related complications included cyclophosphamide-induced cardiac toxicity in 3 of 21 patients (14%) and grade II or greater GVHD in 6 patients (29%). One patient (5%) died from a complication of BMT, and 1 patient (5%) died from GVHD after 2 prophylactic DLIs were given for conversion of chimerism. In summary, mixed lymphohematopoietic chimerism was reproducibly induced after a novel nonmyeloablative preparative regimen incorporating chemotherapy, peritransplant antithymocyte globulin, and thymic irradiation, allowing for early administration of DLI in 10 of 21 patients. After treatment, striking antitumor responses were observed in the majority of patients with chemotherapy-refractory hematologic malignancies.

TRAG-3, a novel cancer/testis antigen, is overexpressed in the majority of melanoma cell lines and malignant melanoma

BACKGROUND

We have identified a novel cancer/testis antigen, TRAG-3, (Taxol Resistance Associated Gene-3) that was initially discovered in search for new genes involved in drug resistance by differential display. Early study of TRAG-3 revealed minimal to absent expression in various normal tissues and over-expression in many carcinoma cell lines including several melanoma lines.

MATERIALS AND METHODS

Northern and RT-PCR technologies were used to evaluate TRAG-3 expression in numerous cell lines and tumor tissue.

RESULTS

Analysis of a wider panel of normal tissues, 32 melanoma cell lines and 4 malignant melanomas demonstrates TRAG-3 expression in 25 of the 32 melanoma cell lines (78%) and four of four of the malignant melanoma tumors (100%). Of the additional eight normal tissues screened, expression was present in normal testis but absent in all other tissues. RT-PCR evaluation of TRAG-3 reveals two transcripts in many carcinoma cell lines with sequencing of these products demonstrating the 799 bp TRAG-3 transcript and a second alternatively spliced transcript, TRAG-3long TRAG-3 maps to band Xq28 within a MAGE gene complex, however sequence analysis demonstrates that TRAG-3 is not homologous to other known cancer/testis antigens.

CONCLUSION

TRAG-3 appears to be a novel cancer/testis antigen.

High-dose cyclophosphamide + carboplatin and interleukin-2 (IL-2) activated autologous stem cell transplantation followed by maintenance IL-2 therapy in metastatic breast carcinoma - a phase II study

While high-dose chemotherapy and stem cell transplantation is associated with higher complete response rates than conventional chemotherapy in patients with metastatic breast cancer (MBC), its role in conferring a survival advantage is unproven. We report the results of a prospective phase II trial of 33 patients accrued between 1996 to 1998 with chemosensitive MBC, who received cyclophosphamide (Cy) 2000 mg/m2/day and carboplatin (Cb) 600 mg/m2/day for 3 consecutive days, followed by infusion of peripheral blood stem cells cultured in IL-2 for 24 h on day 0 as adoptive immunotherapy. Low-dose interleukin-2 (IL-2) was administered from day 0 to +4 and/or +7 to +11, +14 to +18, +21 to +25, then 5 days per month for 11 months to augment a graft-versus-tumor effect. The results of this study were compared to those of a historical control group treated with an identical high-dose Cb + Cy regimen with SCT but without IL-2 treatment. Only gastrointestinal (GI) toxicity was more frequent in the IL-2 cohort (P = 0.0031). At a median follow-up of 18.6 months, the median progression-free survival (PFS) is 9 months (2.4-40) and the median OS has not been reached yet. The Kaplan-Meier estimated 2 year PFS is 35%, compared with 17% in the control arm (P = 0.73), and the estimated 2 year OS is 78%, compared with 61% in the control arm (P = 0.22). Multivariate analysis showed that ER status was an independent predictor for OS and PFS, and less chemotherapy prior to HDCSCT predicted for a better PFS. These results show that augmenting HDC with IL-2 activated SCT is well-tolerated. Whether a therapeutic advantage is achievable in patients with MBC remains to be determined. Bone Marrow Transplantation (2000) 25, 19-24.

Late onset veno-occlusive disease following high-dose chemotherapy and stem cell transplantation

The original definition of hepatic veno-occlusive disease (VOD), which is still widely accepted, includes onset of the clinical syndrome before day +20 following high-dose chemotherapy (HDC) and stem cell transplantation (SCT). We retrospectively identified four patients following HDC and SCT presenting with late onset VOD occurring at day +24, day +27, day +34 and day +42 post SCT. All patients had moderate VOD, with successful resolution of the VOD before day +100 with optimal supportive therapy. Common risk factors for VOD shared by all four patients included an older age (median age: 60 years), and use of a busulphan-containing regimen. Mean and maximum bilirubin levels for all patients during the VOD syndrome were 2.02, 1.76, 5.09, 2.87 mg/dl and 2.5, 2.2, 8.9 and 4.1 mg/dl, respectively, which correlated well with duration of VOD. All patients encountered platelet transfusion-dependent thrombocytopenia during VOD. Ursodeoxycholic acid was used as VOD prophylaxis beginning at a mean of 33 days prior to onset of VOD. As the cellular target of hepatic VOD is as yet unidentified, it is uncertain whether ursodiol or other common characteristics of patients with late onset VOD influence the pathogenesis and natural history of this disease. We believe that the uncommon clinical entity of late onset VOD, a potentially fatal regimen-related toxicity, should not be ignored as a diagnosis of liver disease after 3 or more weeks following HDC and SCT.

TRAG-3, a novel gene, isolated from a taxol-resistant ovarian carcinoma cell line

The mechanisms responsible for the development of the taxol resistance phenotype are unclear, and are likely explained by multiple mechanisms. To understand the molecular changes associated with drug resistance more fully, a taxol-resistant subline, derived from the human ovarian cancer cell line SKOV-3, was established through selection by culture in incrementally increasing taxol concentrations. Comparison of SKOV-3 to SKOV-3TR by differential display identifies a new gene, TRAG-3 (Taxol Resistance Associated Gene- 3). In comparison to the parental line, SKOV-3, TRAG-3 mRNA is overexpressed in the taxol-resistant cell line SKOV-3TR. The nucleotide sequence of the TRAG-3 cDNA contains an open reading frame of 333bp that predicts for a protein product of 110 amino acids. A GenBank search identifies a cosmid clone containing a genomic sequence corresponding to that of TRAG-3. DNA and protein analysis reveals that TRAG-3 has no homology to any known cDNAs or proteins. Northern analysis demonstrates that TRAG-3 is overexpressed in the taxol-resistant breast cancer cell line MDA 435TR as well as the doxorubicin-resistant multiple myeloma cell lines 8226/DOX40 and 8226/MDR10V. A survey of normal tissue shows minimal or absent TRAG-3 mRNA expression. Screening of a wide variety of cancer cell lines demonstrates TRAG-3 expression in many cell lines derived from different tissue types. In summary, TRAG-3 is a novel gene whose expression is associated with the chemotherapy-resistant and neoplastic phenotype.

Vinorelbine induces apoptosis and caspase-3 (CPP32) expression in leukemia and lymphoma cells: a comparison with vincristine

Vinorelbine (NVB) is a novel vinca alkaloid FDA approved for use in some advanced carcinomas. However, its role in non-Hodgkin's lymphoma (NHL) is still not well defined. NVB is an antimicrotubule agent, but as yet, it is not known whether it induces apoptosis. By flow cytometry using nuclear staining (propidium iodide) and annexin V, we demonstrated that NVB and vincristine (VCR) induced both mitotic arrest and apoptosis in leukemia and lymphoma cells, in a drug exposure time dependent manner. Cell cycle kinetics in 3 different cell lines varied during vinca alkaloid treatment. The annexin V method showed that apoptosis, as opposed to necrosis, was the dominant mode of cell kill of chemosensitive leukemia and lymphoma cells. Phosphatidylserine expression on the cell surface was detectable as a hallmark of apoptosis at earlier drug exposure when compared to conventional flow cytometry with PI staining. By Western blot analysis, we demonstrated that CPP32 or caspase-3, a critical apoptosis inducer, and its active subunits p20 and p11 were upregulated in chemo- and apoptosis-sensitive lymphoma and leukemia cells treated with NVB. Our data contributes to the emerging hypothesis suggesting that widely divergent exogenous stimuli and chemotherapeutic agents can effect apoptosis in cancer cells via different pathways involving the caspases. We believe that vinorelbine may be a potentially important drug in the treatment of NHL in the future.

Primary pulmonary lymphoma--clinical review from a single institution in Singapore

Primary pulmonary lymphoma is a rare and vexing subset of extranodal non-Hodgkin's lymphoma. We report 11 cases and provide a brief literature review. We also highlight an unusual case of a relapsed peripheral T-cell primary lung lymphoma that underwent apparent spontaneous remission. Eleven cases of primary pulmonary lymphoma treated in our institution were studied for their clinical characteristics, behaviour, response to treatment and clinical outcome. The median duration of follow up was 26 months. The mean age was in the 50s and the presenting symptoms generally respiratory and non-specific. LDH levels did not correlate with either stage or grade of disease. Lower lobe involvement was most common and nodules and mass-like lesions the main radiologic feature. Small lymphocytic lymphoma accounted for the majority of cases and were indolent in behaviour. Good symptom control and radiologic response was achieved with chemotherapy in disseminated low grade lung lymphomas. Combination chemotherapy was effective in the aggressive lymphomas. In conclusion, Small lymphocytic lymphoma of the lung is an indolent disease with a long symptom-free survival even after recurrence. Our series confirms the clinical characteristics of primary pulmonary lymphoma. The role of Ling Zhi in effecting the spontaneous remission in the peripheral T-cell lymphoma is speculative.