Abstract 212: Identification by mass spectrometry of unique phosphoproteins subsequent to signaling through c-ErbB2

The receptor tyrosine kinase c-ErbB2 is amplified in breast and ovarian cancer. The linear pathways through which signals by c-ErbB2 are transduced is well known. However, second generation questions that address spatial aspects of signaling remain. To address this, we have undertaken a mass spectrometry approach to identify phosphoproteins. We have used two tyrosine kinase inhibitors, Lapatinib and CP724714, that inhibit phosphorylation of c-ErbB2 to identify phosphoproteins. SKOV-3, an ovarian cancer cell line that endogenously overexpresses c-ErbB2 was grown in culture without serum for 72 hrs. Cells were then stimulated in the presence or absence of inhibitor with EGF (100ng/ml) as a ligand for 60 mins. Subsequently, cells were lysed and evaluated by western blotting with anti-phosphotyrosine antibody (4G10). Following stimulation of cells with EGF, maximal phosphorylation of c-ErbB2 was observed at 60 minutes. Lapatinib (10μM) and CP724714 (15μM) completely inhibited phosphorylation of c-ErbB2, which was confirmed by immunoprecipitation. This was further confirmed by the inhibition of downstream effectors (Erk1/2, Akt). Lapatinib (10 μM) also completely inhibited phosphorylation of EGFR while CP724714 (15μM) only inhibited partially. Cellular lysates were prepared from quiescent cells (grown without serum), after stimulation with EGF in the presence or absence of inhibitors. Purified phosphoproteins from all three samples following digestion with trypsin were subjected to mass spectrometry (Nano LC ESI MS/MS). We identified totally 62 phosphoproteins. Twenty seven phosphoproteins were observed in all the 3 samples while 17 phosphoproteins were identified both in the EGF stimulated and lapatinib treated samples. Eighteen unique phosphoproteins were observed only in the EGF stimulated sample suggesting that they are specific to signaling by c-ErbB2. The novel phosphoproteins included the proteins that partcipate in carbohydrate metabolism,cytoskeleton, cell migration and proliferation. We have evaluated two phosphoproteins, LASP-1 and Aldose reductase that has not been previously described following phosphorylation of c-ErbB2. LASP-1 is an oncogene and is located as the same arm 17q21 as c-ErbB2. It was not expressed in the normal ovary or fallopian tube. However, it was over-expressed in 17% of tumours (n=85) from patients with ovarian cancer. c-ErbB2 was not expressed in tumours that expressed LASP1. Aldose reductase is a cytosolic NADPH dependent oxidoreductase that catalyzes the reduction of glucose to sorbitol, the first step in polyol pathway of glucose metabolism. The activity of aldose reductase in reducing NADPH as a substrate was significantly higher in lysates from EGF stimulated as compared to the starved cells. Identification of phosphoproteins by using mass spectrometry is promising in identifying novel substrates and pathways following phosphorylation of c-ErbB2.

Citation Format: C Sidhanth, Manoj Garg, P Manasa, S Krishna Priya, S Bindhya, S Sneha, R.P. Nagare, S Shirley, M Kanchan, Trivadi S. Ganesan. Identification by mass spectrometry of unique phosphoproteins subsequent to signaling through c-ErbB2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 212. doi:10.1158/1538-7445.AM2017-212

Molecular mechanism and therapeutic implications of selinexor (KPT-330) in liposarcoma

Exportin-1 mediates nuclear export of multiple tumor suppressor and growth regulatory proteins. Aberrant expression of exportin-1 is noted in human malignancies, resulting in cytoplasmic mislocalization of its target proteins. We investigated the efficacy of selinexor against liposarcoma cells both in vitro and in vivo. Exportin-1 was highly expressed in liposarcoma samples and cell lines as determined by immunohistochemistry, western blot, and immunofluorescence assay. Knockdown of endogenous exportin-1 inhibited proliferation of liposarcoma cells. Selinexor also significantly decreased cell proliferation as well as induced cell cycle arrest and apoptosis of liposarcoma cells. The drug also significantly decreased tumor volumes and weights of liposarcoma xenografts. Importantly, selinexor inhibited insulin-like growth factor 1 (IGF1) activation of IGF-1R/AKT pathway through upregulation of insulin-like growth factor binding protein 5 (IGFBP5). Further, overexpression and knockdown experiments showed that IGFBP5 acts as a tumor suppressor and its expression was restored upon selinexor treatment of liposarcoma cells. Selinexor decreased aurora kinase A and B levels in these cells and inhibitors of these kinases suppressed the growth of the liposarcoma cells. Overall, our study showed that selinexor treatment restored tumor suppressive function of IGFBP5 and inhibited aurora kinase A and B in liposarcoma cells supporting the usefulness of selinexor as a potential therapeutic strategy for the treatment of this cancer.

Outcomes in Lung Cancer: 9-Year Experience From a Tertiary Cancer Center in India

Purpose

Lung cancer is the most common cause of cancer mortality in the world. There are limited studies on survival outcomes of lung cancer in developing countries such as India. This study analyzed the outcomes of patients with lung cancer who underwent treatment at Cancer Institute (WIA), Chennai, India, between 2006 and 2015 to determine survival outcomes and identify prognostic factors.

Patients and Methods

In all, 678 patients with lung cancer underwent treatment. Median age was 58 years, and 91% of patients had non–small-cell lung cancer (NSCLC). Testing for epidermal growth factor receptor mutation was performed in 132 of 347 patients and 61 (46%) were positive.

Results

Median progression-free survival was 6.9 months and overall survival (OS) was 7.6 months for patients with NSCLC. Median progression-free survival was 6 months and OS was 7.2 months for patients with small-cell lung cancer. On multivariable analysis, the factors found to be significantly associated with inferior OS in NSCLC included nonadenocarcinoma histology, performance status more than 2, and stage. In small-cell lung cancer, younger age and earlier stage at presentation showed significantly better survival.

Conclusion

Our study highlights the challenges faced in treating lung cancer in India. Although median survival in advanced-stage lung cancer is still poor, strategies such as personalized medicine and use of second-line and maintenance chemotherapy may significantly improve the survival in patients with advanced-stage lung cancer in developing countries.

Pediatric Hodgkin Lymphoma Treated at Cancer Institute, Chennai, India: Long-Term Outcome

Purpose

Pediatric Hodgkin lymphoma (HL) is a highly curable malignancy. Outcomes for pediatric HL may vary between developed and developing countries for multiple reasons. This study was conducted to ascertain the outcomes of children with HL at our center and to identify risk factors for recurrent disease.

Methods

We analyzed the outcomes of 172 consecutive, previously untreated patients with pediatric HL presenting at our center from 2001 to 2010. Patients were treated with either adriamycin, bleomycin, vinblastine, and dacarbazine or adriamycin, bleomycin, vinblastine, cyclophosphamide, vincristine, prednisone, and procarbazine chemotherapy initially, and radiation to bulky sites or a single site of residual disease when appropriate.

Results

The median duration of follow-up was 77 months. The median age of the patients was 10 years; 127 (74%) of the 172 patients were male. The extent of disease was stage I and II in 59% of the patients. B symptoms were present in 32% of the patients, and 27% had bulky disease. The most common histologic subtype was mixed cellularity (45%). The 5-year overall survival (OS) and progression-free survival (PFS) of the entire cohort were 92.9% and 83.1%, respectively. The 5-year OS rates for patients with stage I, II, III, and IV were 96%, 94.7%, 84%, and 69.8%, respectively. On univariate analysis, advanced stage, response on interim radiologic assessment, and presence of B symptoms significantly predicted inferior PFS and OS. On multivariate analysis, only interim radiologic response significantly predicted PFS (P < .001) and OS (P < .001).

Conclusion

Overall, the outcomes of patients treated at our center are comparable to those observed in other centers in India and globally.

Expression of a novel endothelial marker, C-type lectin 14A, in epithelial ovarian cancer and its prognostic significance

OBJECTIVE

The purpose of this study was to evaluate microvessel density (MVD) as assessed by C-type lectin 14A (CLEC14A), which is a new marker for endothelial cells, and compare its expression to CD31 and CD105 in epithelial ovarian cancer (EOC).

METHODS

MVD was evaluated in tumors (n = 50) from patients with EOC who underwent primary surgery and in patients with EOC who received preoperative chemotherapy (n = 49) using immunohistochemistry with antibodies to CLEC14A, CD31 and CD105. The median duration of follow-up was 24.5 months (range 1-101 months). The effect of prognostic factors on event-free survival (EFS) and overall survival (OS) was assessed using the Cox regression model.

RESULTS

The amount of residual disease was found to be an independent prognostic factor in multivariate analysis with respect to EFS (P = 0.009) and OS (P < 0.001). The mean MVD of CLEC14A (MVD = 6), in tumors from patients who underwent primary surgery, was significantly lower than that of CD31 (MVD = 25, P < 0.0001) and CD105 (MVD = 11, P = 0.018). However, there was no significant correlation between MVD as detected by these markers and clinical outcome. There was no expression of CLEC14A in tumors from patients who received preoperative chemotherapy and the MVD of CD31 and CD105 was significantly reduced (P = 0.001 and 0.006, respectively) in this set of patients.

CONCLUSION

This study demonstrates MVD as detected by CLEC14A in EOC. Treatment with chemotherapy reduces tumor blood vessels significantly. We suggest that CLEC14A may be a more specific endothelial marker to assess tumor angiogenesis.

Lymphoblastic lymphoma presenting as bilateral renal enlargement diagnosed by percutaneous kidney biopsy: Report of three cases

Renal involvement by lymphoma can be a diagnostic challenge. Acute kidney injury (AKI) is an unusual manifestation of lymphomatous infiltration in the kidneys. We report three cases of lymphoblastic lymphoma, a very rare form of lymphoma, presenting with AKI and bilateral enlargement of kidneys, diagnosed by percutaneous kidney biopsy. Lymphomatous infiltration should be suspected with such clinical presentation. Kidney biopsy is a valuable diagnostic tool, to establish the correct diagnosis and subtype of lymphoma for timely initiation of therapy for these aggressive hematological malignancies.

Abstract 3330: Tumor angiogenesis and cancer stem cells in serous adenocarcinoma of the ovary

Angiogenesis is required for tumor growth and metastasis. The conventional view of tumour angiogenesis is that tumours get their blood supply from the neighbouring normal stroma. However, recently the origin of tumour endothelial cells or pericytes in part has been shown to be derived from cancer stem cells (CSC) in glioma. The spread of ovarian cancer (SOC) is different and the origin of endothelial cells in the tumor is not known. Using spheroids as an in vitro model (which is enriched for CSC), we have evaluated the role of CSC in primary malignant cells (PMCs) from patients with serous adenocarcinoma of ovary (n = 30) cultured under endothelial conditions. The expression of endothelial markers (CD31, CD105, and CLEC14a) was evaluated by flow cytometry. Further, the ability of CSC to express endothelial markers under appropriate growth conditions was also evaluated with Bevacizumab (Avastin) or Cediranib which antagonize VEGF or its receptor (VEGFR2) respectively. In addition, functional assays such as uptake of Dil labelled acetylated low density lipoprotein (Dil-ac-LDL) and expression of endothelial nitric oxide synthase (e-NOS) was performed to assess the endothelial phenotype. The localization of tumour blood vessels and CSC in primary ovarian tumors was examined by double immunohistochemistry of CD31/CD105/CLEC14a and ALDH1a1. Primary malignant cells (n = 30) grown in endothelial growth medium (EGM) showed significantly higher expression of CD105 (mean 20.8%, p = 0.001) and CLEC14a (mean 5.3%, p = 0.012) and a co-expression of CD105/CLEC14a (mean 1.6%, p = 0.012) than that of control (mean, 12.5%, 2.5% and 0.95% respectively). The co-expression of ALDH1a1 with endothelial markers, CD31, (mean, 1.58%), CD105, (mean 0.7%), CLEC14a (mean 0.44%) in primary malignant cells (n = 5), denovo, suggest that there is a small proportion of cells which are in transit to form endothelial cells. When the primary malignant cells were grown as spheroids in endothelial conditions in the presence or absence of Avastin (1 μg/μl), there was reduction in the expression of CD105 (mean, 12.5% (EGM) and 7.9% (Avastin), P = 0.056) and CLEC14a (mean. 5.5% (EGM) and 1.5% (Avastin), P = 0.04). However, when the spheroids were cultured in presence of cediranib (10 nM), the expression of CD105 was not reduced (Mean, 2.53% (EGM) and 4% (cediranib). The cells grown in endothelial conditions showed uptake of Dil-ac-LDL (n = 3) and expressed e-NOS (n = 3), confirming their endothelial phenotype. The double immunostaining with ALDH1a1 and CD31/CD105 demonstrated that the blood vessels were in proximity to ALDH1A1+ cells in primary serous adenocarcinoma of the ovary (n = 5). These results suggest that a proportion of endothelial cells (probably 20%) could be derived from CSC in serous ovarian carcinoma and the VEGF pathway has an important role. This property of CSC to contribute to tumour angiogenesis can be inhibited.

Citation Format: Syama Krishna Priya, Rohit P. Nagare, V S. Sneha, C Sidhanth, S Bindhya, P Manasa, Trivadi S. Ganesan. Tumor angiogenesis and cancer stem cells in serous adenocarcinoma of the ovary. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3330.

Tumour angiogenesis-Origin of blood vessels

The conventional view of tumour vascularization is that tumours acquire their blood supply from neighbouring normal stroma. Additional methods of tumour vascularization such as intussusceptive angiogenesis, vasculogenic mimicry, vessel co-option and vasculogenesis have been demonstrated to occur. However, the origin of the endothelial cells and pericytes in the tumour vasculature is not fully understood. Their origin from malignant cells has been shown indirectly in lymphoma and neuroblastoma by immuno-FISH experiments. It is now evident that tumours arise from a small population of cells called cancer stem cells (CSCs) or tumour initiating cells. Recent data suggest that a proportion of tumour endothelial cells arise from cancer stem cells in glioblastoma. This was demonstrated both in vitro and in vivo. The analysis of chromosomal abnormalities in endothelial cells showed identical genetic changes to those identified in tumour cells. However, another report contradicted these results from the earlier studies in glioblastoma and had shown that CSCs give rise to pericytes and not endothelial cells. The main thrust of this review is the critical analysis of the conflicting data from different studies and the remaining questions in this field of research. The mechanism by which this phenomenon occurs is also discussed in detail. The transdifferentiation of CSCs to endothelial cells/pericytes has many implications in the progression and metastasis of the tumours and hence it would be a novel target for antiangiogenic therapy.

Acute lymphoblastic leukemia: A single center experience with Berlin, Frankfurt, and Munster-95 protocol

BACKGROUND

There is a paucity of data on the outcome following the treatment for acute lymphoblastic leukemia (ALL) from developing countries.

MATERIALS AND METHODS

Two hundred and thirty-eight consecutive patients with ALL <30 years of age diagnosed between January 2005 and December 2011 were analyzed retrospectively. Patients were treated modified Berlin, Frankfurt, and Munster 95 protocol. Event-free survival (EFS) was calculated using Kaplan-Meier survival analysis and variables were compared using log-rank test.

RESULTS

The EFS was 63.4% at a median follow-up was 32.7 months. On univariate analysis National Cancer Institute (NCI) risk stratification, sex, white blood cell count, day 8 blast clearance, and income were significantly associated with EFS. However, on multivariate analysis only female sex (P = 0.01) and day 8 blast clearance (P = 0.006) were significantly associated with EFS. Seventy-four of 238 (31%) patients had recurrent leukemia. The common sites of relapse were bone marrow in 55/74 (75%) patients and central nervous system in 11/74 (20%) patients.

CONCLUSION

Compared to western data, there was an increased proportion of NCI high-risk patients and T-cell immunophenotype in our study. There has been an improvement in outcome of patients with ALL at our center over the last 2 decades. Female sex and clearance of blast in peripheral blood by day 8 of induction was associated with better EFS.

Abstract 1392: ALDH1A1 is the best marker by a composite approach for cancer stem cells in ovarian cancer whose integrity is controlled by the hedgehog pathway

Cancer Stem Cells (CSCs) express distinct surface markers and have unique functional properties that distinguish them from the rest of the cells in a tumour. There have been variability in the identity of CSC markers in serous adenocarcinoma of the ovary. We have taken a composite approach for evaluating surface markers together with functional assays in primary tumours (n = 20). Expression of CSC markers were evaluated by flow cytometry, immunofluorescence (IF) and immunohistochemistry (IHC) in cell lines (n = 8), primary malignant cells (PMC, n = 20) and normal ovary (n = 2). The ALDEFLUOR assay was used to identify CSCs individually (n = 20) and together with surface markers (n = 6). PMC (n = 5) were grown as spheroids to evaluate expression of markers and ALDEFLUOR assay (n = 3). The role of signaling by Notch, Wnt and Hedgehog pathways were evaluated to ascertain maintenance of CSCs in the spheroid model (n = 3) using specific small molecule inhibitors. PMC (n = 20) were grown in the presence or absence of inhibitors for 2 weeks and CSC markers evaluated to ascertain specificity of effect along with motility assays. We identified 3 novel surface markers in silico (CD9, CD24 and EPHA1) in addition to those previously detected (CD133, CD117, CD44). The surface markers CD117 and CD9 were expressed in ovarian surface epithelium. CD117, CD9 and ALDH1A1 also showed expression in the fallopian tube by IHC. PMC expressed individually CD44 (57.7±3.2), CD117 (12.5±6.1), CD133 (09.7±3.9), CD9 (11.1±7.2), CD24 (34.6±4.9), Epha1 (16.4±3.1) by flow cytometry. Co expression of markers in the same cells (n = 20) were (11.33±5.32). PMC expressed ALDH1A1 (2.5±0.2) and a fraction of these cells co-expressed CSC surface markers (2.09 ± 0.08). ALDH1A1 expressing malignant cells (n = 5) were predominantly in G0/G1 phase (67.2±2.6) of the cell cycle. Spheroids expressed all the above CSC markers by IF. In addition, ALDH1A1 was expressed in spheroids suggesting that these are enriched for CSCs. Spheroid formation in OVCAR3 and UC1101 cells was inhibited completely by the Hedgehog pathway inhibitor (SMO) GDC0449 (3μM). Flow cytometry analysis of PMC showed significant reduction in expression of ALDH1A1 (2.5±0.9), CD44 (18.6±5.5), CD9 (1.6±0.8), CD133 (0.5±0.3), CD117 (18.8±13.4), CD24 (0.1±0) after incubation with GDC0449. Similar results were obtained with two other inhibitors, LDE225 (SMO, 2.5nM) and GANT61 (Gli, 5μM). Significant reduction in migration of PMC was observed in the scratch assay in the presence of inhibitors. These results demonstrate that ALDH1A1 expression is consistently low in PMC and is the most reliable marker for CSCs. There was wide variability of expression of the surface markers in PMC and none uniquely co-expressed with ALDH1A1. The hedgehog signaling pathway is important in maintaining the integrity of CSCs. Targeting components of this pathway may be an alternate approach for treating ovarian cancer.

Citation Format: Rohit P. Nagare, S Sneha, S Krishnapriya, Trivadi S. Ganesan. ALDH1A1 is the best marker by a composite approach for cancer stem cells in ovarian cancer whose integrity is controlled by the hedgehog pathway. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1392. doi:10.1158/1538-7445.AM2015-1392

Phase II study of interim PET-CT-guided response-adapted therapy in advanced Hodgkin's lymphoma

BACKGROUND

Combination chemotherapy ABVD (doxorubicin, bleomycin, vinblastine and dacarabazine) cures ∼70% of patients with advanced Hodgkin's lymphoma (aHL, stages IIB, III and IV) while more toxic escalated BEACOPP (EB, combination of bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine and prednisolone) increases cure rates to 85%. Patients with a positive interim positron emission tomography-computerized tomography (PET-CT) scan after two cycles (PET-2) of ABVD have very poor outcomes with continued ABVD. Intensifying therapy with EB in PET-2-positive patients ('response-adapted therapy') may improve cure rates, whereas the negative patients can continue ABVD alone.

PATIENTS AND METHODS

Eligible patients with newly diagnosed aHL received two cycles of ABVD and underwent PET-2 (scored with semi-quantitative 5-point visual criteria, 'Deauville score'). PET-2-negative patients continued four additional cycles of ABVD, whereas PET-2-positive patients received four cycles of EB. A phase II sample size of 50 was estimated keeping the lower and higher proportion of rejection of the event-free survival (EFS) as 70% and 85%, respectively.

RESULTS

Fifty patients [median age 28 (12-60) years; male : female: 39 : 11; stages: IIB-3 (6%), III-29 (58%) and IV-18 (36%); International Prognostic Score (IPS): 0-3: 34 (68%); 4-7: 16 (32%)] were enrolled; 49 underwent PET-2. Eight (16%) were PET-2-positive, whereas 41 (84%) were negative. Forty-seven were evaluable for EFS and all 50 for overall survival (OS). The 2-year EFS was 76% (95% CI: 68-83) and OS was 88% (95% CI: 82-94). PET-2 was strongly prognostic-2-year EFS, negative versus positive: 82% versus 50%; P = 0.013.

CONCLUSION

PET-2 response-adapted strategy could not achieve EFS of 85% in aHL. However, escalated therapy improved outcomes in PET-2-positive patients compared with historical data.

TRIAL REGISTRATION

CTRI/2012/06/002741 (http://www.ctri.nic.in) and NCT01304849 (http://www.clinicaltrials.gov).

The tumor suppressor RASSF1A is a novel effector of small G protein Rap1A

Rap1A is a small G protein implicated in a spectrum of biological processes such as cell proliferation, adhesion, differentiation, and embryogenesis. The downstream effectors through which Rap1A mediates its diverse effects are largely unknown. Here we show that Rap1A, but not the related small G proteins Rap2 or Ras, binds the tumor suppressor Ras association domain family 1A (RASSF1A) in a manner that is regulated by phosphorylation of RASSF1A. Interaction with Rap1A is shown to influence the effect of RASSF1A on microtubule behavior.

A prospective randomised phase II trial of thalidomide with carboplatin compared with carboplatin alone as a first-line therapy in women with ovarian cancer, with evaluation of potential surrogate markers of angiogenesis

OBJECTIVES

To compare the safety and efficacy of thalidomide in combination with carboplatin to carboplatin alone as a first-line therapy in women with ovarian cancer and to evaluate the anti-angiogenic effects of thalidomide by measurement of surrogate markers of angiogenesis.

METHODS

Forty patients with Stage IC-IV ovarian cancer were randomly assigned to receive either carboplatin (AUC 7) intravenously every four weeks for up to six doses (n = 20) or carboplatin at the same dose and schedule, plus thalidomide 100 mg orally daily for six months (n = 20).

RESULTS

After median follow-up of 1.95 years, there was no difference in the overall response rate (90% in carboplatin arm, 75% in combination arm; p = 0.41). Increased incidence of symptoms of constipation, dizziness, tiredness and peripheral neuropathy was observed in the combination arm. There was a significant fall in CA-125 and E-selectin in both arms after treatment and VCAM-1 in the carboplatin arm. No significant difference between the two arms was observed in any of the markers analysed.

CONCLUSIONS

In our trial the addition of thalidomide to carboplatin was well tolerated with no increased efficacy. The fall in some of the angiogenic markers in both groups may reflect tumour response rather than any specific anti-angiogenic effect of thalidomide.

A simple and efficient method for processing of cell lysates for two-dimensional gel electrophoresis

Sample preparation is one of the major issues in 2-DE for the separation of proteins. Although a 100% representation of cellular proteins onto a 2-DE is virtually impossible, maximum representation of cellular proteins compared with the original cell lysate is important in the subsequent analysis. We demonstrate that lysis of cells in urea/thiourea solution with subsequent sonication to disrupt the nucleic acids and concentration of the lysate using centri-con led to enrichment of proteins. The procedure resulted in minimal nucleic acid contamination with better resolution of spots. 2-DE spot patterns of proteins prepared using urea-thiourea solubilization/centri-con method to other protein enrichment methods such as phenol/chloroform/isoamyl alcohol extraction, methanol/ammonium acetate precipitation, acetone precipitation and ethanol precipitation were compared. Urea-thiourea solubilization combined with centri-con method of protein enrichment represented higher number/unique spots particularly in the 50-250 kDa M(r) compared with others. Lysis of cells in urea/thiourea from the beginning of lysate preparation preserves the proteins from protease activity due to denaturation of proteases. Thus, we demonstrate that the centri-con methodology is simple and effective for the preparation of high-quality sample that can be used for a qualitative representation of cellular proteins on a 2-DE for proteomic analysis.

The tumour suppressor RASSF1A is a novel substrate of PKC

Ras association domain family 1A (RASSF1A) is a tumour suppressor that contains an amino-terminal cysteine-rich region, similar to the diacylglycerol (DAG)-binding domain (C1 domain) found in the protein kinase C (PKC) family of proteins, and a carboxy-terminal Ras-association (RA) domain. In the present study, RASSF1A was identified as a substrate for PKC. Using classical biochemical approaches, it was established that S197 and S203 within the RA domain of RASSF1A are phosphorylated by PKC in vitro and in vivo. Unlike the WT protein, the S197, 203D double mutant of RASSF1A failed to modulate microtubule organization and perinuclear vimentin collapse. By contrast, the equivalent AA mutant of RASSF1A phenocopied the WT protein. These findings indicate that PKC phosphorylation of RASSF1A regulates its ability to reorganize the microtubule network.

Role of lymphangiogenesis in cancer

Regional lymph node metastasis is a common event in solid tumors and is considered a marker for dissemination, increased stage, and worse prognosis. Despite rapid advances in tumor biology, the molecular processes that underpin lymphatic invasion and lymph node metastasis remain poorly understood. However, exciting discoveries have been made in the field of lymphangiogenesis in recent years. The identification of vascular endothelial growth factor ligands and cognate receptors involved in lymphangiogenesis, an understanding of the embryology of the mammalian lymphatic system, the recent isolation of pure populations of lymphatic endothelial cells, the investigation of lymphatic metastases in animal models, and the identification of markers that discriminate lymphatics from blood vessels at immunohistochemistry are current advances in the field of lymphangiogenesis, and as such are the main focus of this article. This review also evaluates evidence for lymphangiogenesis (ie, new lymphatic vessel formation in cancer) and critically reviews current data on the prognostic significance of lymphatic vascular density in tumors. A targeted approach to block pathways of lymphangiogenesis seems to be an attractive anticancer treatment strategy. Conversely, promotion of lymphangiogenesis may be a promising approach to the management of treatment-induced lymphedema in cancer survivors. Finally, the implications of these developments in cancer therapeutics and directions for future research are discussed.

Role of lymphangiogenesis in epithelial ovarian cancer

We investigated the significance of lymphatic count, vascular count and angiogenic growth factors using immunohistochemistry in 108 tumour specimens of epithelial ovarian cancer with antibodies to lymphatic vessel endothelial hyaluronan receptor (LYVE-1), platelet endothelial cell adhesion molecule CD31, vascular endothelial growth factor (VEGF) and thymidine phosphorylase (TP) in epithelial ovarian cancer to understand the pathogenesis of metastasis in ovarian cancer. The effect of prognostic variables on progression-free and overall survival was assessed. On multivariate analysis, bulky residual disease after surgery was the best prognostic indicator (P<0.001) for progression-free and overall survival (P<0.001). Lymphatic count was statistically significant as a prognostic factor for progression-free (P=0.05) and overall survival (P=0.04). However, lymphatic count did not impact on survival curves. No correlation was found between lymphatic count and age, histological subtype, FIGO stage or residual disease. Vascular count, VEGF or TP expressions were not significant in either analysis. Lymphatic spread may be significant in aiding metastases in ovarian cancer but requires other biological factors to act in conjunction, as it does not have clearcut prognostic significance. Dissemination of ovarian cancer does not occur primarily through vascular or lymphatic routes but may occur through direct intraperitoneal spread of disease.

RPS6KA2, a putative tumour suppressor gene at 6q27 in sporadic epithelial ovarian cancer

We had previously defined by allele loss studies a minimal region at 6q27 (between D6S264 and D6S297) to contain a putative tumour suppressor gene. The p90 ribosomal S6 kinase-3 gene (p90 Rsk-3, RPS6KA2) maps in this interval. It is a serine-threonine kinase that signals downstream of the mitogen-activated protein kinase pathway. It is expressed in normal ovarian epithelium, whereas reduced or absent in tumours or cell lines. We show that RPS6KA2 is monoallelically expressed in the ovary suggesting that loss of a single expressed allele is sufficient to cause complete loss of expression in cancer cells. Further, we have identified two new isoforms of RPS6KA2 with an alternative start codon. Homozygous deletions were identified within the RPS6KA2 gene in two cell lines. Re-expression of RPS6KA2 in ovarian cancer cell lines suppressed colony formation. In UCI101 cells, the expression of RPS6KA2 reduced proliferation, caused G1 arrest, increased apoptosis, reduced levels of phosphorylated extracellular signal-regulated kinase and altered other cell cycle proteins. In contrast, small interfering RNA against RPS6KA2 showed the opposite effect in 41M cells. The above results suggest that RPS6KA2 is a putative tumour suppressor gene to explain allele loss at 6q27.

Involvement of MINK, a Ste20 Family Kinase, in Ras Oncogene-Induced Growth Arrest in Human Ovarian Surface Epithelial Cells

The ability of activated Ras to induce growth arrest of human ovarian surface epithelial (HOSE) cells via induction of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) has been used to screen for Ras pathway signaling components using a library of RNA interference (RNAi) vectors targeting the kinome. Two known Ras-regulated kinases were identified, phosphoinositide 3-kinase p110alpha and ribosomal protein S6 kinase p70(S6K1), plus the MAP kinase kinase kinase kinase MINK, which had not previously been implicated in Ras signaling. MINK is activated after Ras induction via a mechanism involving reactive oxygen species and mediates stimulation of the stress-activated protein kinase p38 MAPK downstream of the Raf/ERK pathway. p38 MAPK activation is essential for Ras-induced p21(WAF1/CIP1) upregulation and cell cycle arrest. MINK is thus a distal target of Ras signaling in the induction of a growth-arrested, senescent-like phenotype that may act to oppose oncogenic transformation in HOSE cells.

Pharmacokinetically guided phase I trial of topotecan and etoposide phosphate in recurrent ovarian cancer

A pharmacokinetically guided phase I study of topotecan and etoposide phosphate was conducted in recurrent ovarian cancer. The scheduling of the topoisomerase I and II inhibitors was determined using in vitro activity data. All patients had recurrent disease following prior platinum-containing chemotherapy. Patients had a World Health Organisation performance status of 0–2 and adequate bone marrow, renal and hepatic function. Treatment was with topotecan intravenously for 5 days followed immediately by a 5-day intravenous infusion of etoposide phosphate (EP), with pharmacokinetically guided dose adjustment. Plasma etoposide levels were measured on days 2 and 4 of the infusion. A total of 21 patients entered the study. In all, 48% were platinum resistant and 71% had received prior paclitaxel. The main toxicities were haematological, short lived and reversible. A total of 29% of patients experienced grade 4 thrombocytopenia and 66% grade 4 neutropenia after the first cycle. Neutropenia and thrombocytopenia was dose limiting. The maximum-tolerated dose was topotecan 0.85 mg m⁻² day⁻¹ days 1–5 followed immediately by a 5-day infusion of EP at a plasma concentration of 1 μg ml⁻¹. The response rate (RR) was 28% in 18 evaluable patients. There was marked interpatient variability in topoisomerase IIα levels measured from peripheral lymphocytes, with no observed increase following topotecan. This regimen of topotecan followed by EP demonstrated good activity in recurrent ovarian cancer and was noncrossresistant with paclitaxel. Both the toxicity and RR was higher than would be expected from the single agent data, in keeping with synergy of action.

Study of etanercept, a tumor necrosis factor-alpha inhibitor, in recurrent ovarian cancer

PURPOSE

Convincing data support the link between inflammation and ovarian cancer. Tumor necrosis factor-alpha (TNF-alpha), a major mediator of inflammation, is chronically produced in the ovarian tumor microenvironment and may enhance tumor growth and invasion by inducing the secretion of cytokines, proangiogenic factors, and metalloproteinases. Etanercept is a recombinant human soluble p75 TNF receptor that binds to TNF-alpha and renders it biologically unavailable. In the current study, we sought to determine the toxicity, biologic activity, and therapeutic efficacy of etanercept in recurrent ovarian cancer.

PATIENTS AND METHODS

We initiated a phase I-B, nonrandomized, open-label study in patients with recurrent ovarian cancer. Etanercept was administered subcutaneously at a dose of 25 mg twice weekly (cohort one) and 25 mg thrice weekly (cohort two) until disease progression.

RESULTS

Thirty patients were recruited (cohort one, 17 patients; cohort two, 13 patients). Eighteen of the 30 patients (cohort one, 11 patients; cohort two, seven patients) completed > or = 12 weeks of treatment. Six patients achieved prolonged disease stabilization (cohort one, two patients [40 and 25 weeks]; cohort two, four patients [34, 24, 22, and 24 weeks]). A significant rise in immunoreactive TNF was seen in all patients (pretreatment compared with end of treatment). A phytohemagglutinin-stimulated whole-blood cytokine assay showed a significant fall in interleukin-6 (cohort one [11 of 17]) and CCL2 (cohort one [13 of 17]) levels. Common adverse effects were injection-site reactions and fatigue.

CONCLUSION

We provide evidence for the biologic activity and safety of etanercept in recurrent ovarian cancer. Our data suggest possible clinical activity that must be confirmed in future studies.

A phase II study of etanercept (Enbrel), a tumor necrosis factor alpha inhibitor in patients with metastatic breast cancer

PURPOSE

Tumor necrosis factor (TNF) alpha is a key player in the tumor microenvironment and is involved in the pathogenesis of breast cancer. Etanercept is a recombinant human soluble p75 TNF receptor that binds to TNF-alpha and renders it biologically unavailable. In the current study, we sought to determine the toxicity, biological activity, and therapeutic efficacy of Etanercept in metastatic breast cancer.

EXPERIMENTAL DESIGN

We initiated a Phase II, nonrandomized, open-labeled study in patients with progressive metastatic breast cancer refractory to conventional therapy (Phase I toxicity data were available in patients with rheumatoid arthritis). Etanercept was administered subcutaneously at a dose of 25 mg twice weekly until disease progression.

RESULTS

Sixteen patients were recruited [median age 53 years (range, 34 to 74)]. A total of 141.6 weeks of therapy was administered (median of 8.1 weeks). Seven patients received > or =12 weeks of therapy. The most common side effects were injection site reactions (6), fatigue (5), loss of appetite (2), nausea (1), headache (1), and dizziness (1). Brief period of disease stabilization was seen in 1 patient lasting for 16.4 weeks. Immunoreactive TNF-alpha was elevated within 24 hours of therapy and persisted until the end of treatment (days 7, 28, 56, and 84). Phytohemagglutinin stimulates the production of interleukin-6 and CCL2 in peripheral blood cells, and the ability of Etanercept to modulate this response was assessed in a cytokine release assay. A consistent decrease in interleukin-6 and CCL2 level was seen compared with pretreatment values in serial blood samples (days 1, 7, 28, 56, and 84).

CONCLUSIONS

Our study shows the safety and biological activity of Etanercept in breast cancer and provides data to assess pharmacodynamic endpoints of different schedules of Etanercept and combinations with chemotherapy or other biological therapies.

Tyrosine kinase inhibitors in cancer therapy

Cancer is the second leading cause of death in the western world. Despite advances in diagnosis and treatment, overall survival of patients remains poor. Scientific advances in recent years have enhanced our understanding of the biology of cancer. Human protein tyrosine kinases (PTKs) play a central role in human carcinogenesis and have emerged as the promising new targets. Several approaches to inhibit tyrosine kinase have been developed. These agents have shown impressive anticancer effects in preclinical studies and are emerging as promising agents in the clinic. The remarkable success of BCR-ABL tyrosine kinase inhibitor imatinib (STI571) in the treatment of chronic myeloid leukaemia has particularly stimulated intense research in this field. At least 30 inhibitors are in various stages of clinical development in cancer, and about 120 clinical trials are ongoing worldwide. In this review, we focus on the role of tyrosine kinases in cancer and the development of specific small molecule inhibitors for therapy. We also provide a critical analysis of the current data on tyrosine kinase inhibitors and highlight areas for future research. Issues with regards to the design of clinical trials with such agents are also discussed. Innovative approaches are needed to fully evaluate the potential of these agents, and a concerted international effort will hopefully help to integrate these inhibitors in cancer therapy in the near future.

Phase II trial of the antiangiogenic agent IM862 in metastatic renal cell carcinoma

IM862 is a naturally occurring dipeptide (L-glu-L-trp) with immunomodulatory and antiangiogenic properties. A significant anticancer activity has been reported recently in AIDS-related Kaposi's sarcoma, a tumour of endothelial cell origin. The high vascularity and responsiveness to immunotherapy of renal cell carcinoma (RCC) makes such a tumour a potential target for IM862. In all, 25 patients were accrued in a prospective phase II trial using a standard two-step design. The main inclusion criteria were WHO performance status ⩽2, age over 18 years, expected survival >3 months, normal marrow, kidney and liver functions. IM862 was given intranasally at a dose of 20 mg three times daily. Each cycle consisted of 8 consecutive weeks of treatment. All 25 patients were fully evaluable for response and 24 for toxicities. Median age was 62 years (range 42–76), median WHO PS was 1 (0–2). No grade 2 or 3 toxicities related to the study drug have been recorded. Eight patients had stable disease (SD) and 17 progressed while on treatment. Median survival was 7.9 months (range 2.7–20). Median time to progression was 1.9 months (range 1.2–12.6). Median duration of SD was 6 months (range 5.2–12.6+). Analysis of blood angiogenic markers showed a significant decrease of plasma vascular endothelial growth factor (VEGF) levels after 4 and 8 weeks of therapy. Treatment with IM862 has no toxicity, but does not lead to any significant objective responses in metastatic RCC. IM862 should not be further evaluated as a single agent at these doses and schedule for this population of patients. The decrease in VEGF levels warrants further investigation of IM862 as an antiangiogenic therapy.

Combination antiangiogenesis therapy with marimastat, captopril and fragmin in patients with advanced cancer

Marimastat, low molecular weight heparins and captopril have antiangiogenic activity in vitro and in animal models. We studied the safety and efficacy of the combination of these drugs in patients with advanced cancer. In all, 50 patients were enrolled. Captopril was given orally at a dose of 50 mg bd daily. Fragmin was administered as a daily subcutaneous injection of 200 units kg⁻¹ for the first 28 days and 5000 units thereafter. Marimastat was given at 10 mg bd orally. Serum, plasma and urinary angiogenic factors were measured at baseline and after 1 month of treatment. Inhibition of release of tumour necrosis factor alpha (TNF-alpha) from peripheral lymphocytes was used as a surrogate pharmacodynamic end point. There was one case of haemorrhagic stroke and one upper gastrointestinal haemorrhage. The commonest toxicity was myalgia. One of 10 patients with renal cancer had a partial response, and three patients had a prolonged period of stable disease. The treatment significantly inhibited phytohaemagglutinin (PHA)-stimulated TNF-alpha release from patient's lymphocytes. The combination of marimastat, fragmin and captopril is well tolerated and has in vivo activity. Inhibition of PHA-stimulated TNF-alpha release from lymphocytes is a surrogate pharmacodynamic marker of metalloprotease inhibition.

A Multicenter Phase I Gene Therapy Clinical Trial Involving Intraperitoneal Administration of E1A-Lipid Complex in Patients with Recurrent Epithelial Ovarian Cancer Overexpressing HER-2/neuOncogene

PURPOSE

HER-2/neu oncogene is overexpressed in 10-30% of epithelial ovarian cancers and is associated with a poor prognosis. The E1A gene product of adenovirus type 5 down-regulates HER-2/neu and causes tumor regression in animal models. In the current study, we sought to determine the toxicity and biological activity of E1A-lipid complex in ovarian cancer patients.

EXPERIMENTAL DESIGN

A Phase I trial involving intraperitoneal (i.p.) administration of E1A-lipid complex was initiated in ovarian cancer patients to assess biological activity (E1A gene transfer/transcription/translation and HER-2/neu expression) and to determine the maximum tolerated dose. Successive cohorts received E1A-lipid complex at doses of 1.8, 3.6, and 7.2 mg DNA/m(2), given as weekly i.p. infusions for 3 of 4 weeks (each cycle) up to a maximum of six cycles. Peritoneal fluid was sampled at baseline and twice monthly for cellularity, cytology, CA-125, and biological activity

RESULTS

Fifteen patients, with a median age of 57 years (range, 43-81) were recruited. Three (1.8 mg DNA/m(2)), 4 (3.6 mg DNA/m(2)), and 8 patients (7.2 mg DNA/m(2)) received i.p. E1A. A total of 91 infusions (range, 1-18) was administered. Abdominal pain was the dose-limiting toxicity, and the maximum-tolerated dose was 3.6 mg DNA/m(2). E1A gene transfer and expression was observed in all of the patients and at all of the dose levels. HER-2/neu down-regulation could be demonstrated in the tumor cells of 2 patients (18%). There was no correlation between dose and biological activity.

CONCLUSIONS

I.P. EIA-lipid complex gene therapy is feasible and safe. Future studies, either alone or in combination with chemotherapy, particularly in patients with minimal residual disease, should be evaluated.

MSI-low, a real phenomenon which varies in frequency among cancer types

This study assessed whether low-level microsatellite instability (MSI-L) is a phenomenon specific to colorectal cancers or is also present in other tumour types. Breast (grade III ductal and lobular), endometrial and ovarian carcinomas, as well as colorectal cancers, were analysed for MSI-L using eight microsatellite markers. The markers were selected from a panel that had previously been shown to be sensitive for the detection of MSI-L in colorectal cancers. It was found that MSI-L was present in 30 of 87 (35%) colorectal cancers, 2 of 59 (3%) grade III breast carcinomas, 1 of 35 (3%) lobular breast cancers, 16 of 50 (32%) endometrial cancers, and 9 of 34 (26%) ovarian cancers. These results suggest that MSI-L is a very rare occurrence in breast carcinomas, but does occur as a real phenomenon in colorectal, endometrial, and ovarian carcinomas, which are all part of the hereditary non-polyposis colon cancer (HNPCC) syndrome. PCR artefact was also found to masquerade as MSI-L; criteria for the assessment of MSI-L are suggested to eliminate this problem.

Comparison of prognostic factors in patients in phase I trials of cytotoxic drugs vs new noncytotoxic agents

The aims of this study were to identify prognostic variables for toxicity and survival in patients with cancer participating in phase I clinical trials and compare characteristics of those treated with cytotoxic chemotherapy (CT) and non-cytotoxic drugs (non-CT). Data were collected from 420 (114 CT, 306 non-CT) patients enrolled in 16 phase I trials (five CT and 11 non-CT trials) in one cancer centre. Analyses of all patients were used to compare treatment groups, identify predictive variables for toxicity and to estimate prognostic factors in overall survival (OS). These were used to develop a prognostic index (PI). Multivariate analysis found those patients with better performance status, fewer sites of metastases, baseline Hb>12 g dl⁻¹ and WBC or LDH in the normal range had significantly better OS. Male gender, platelet count <450 × 10⁹ l⁻¹, high WBC or treatment with a non-CT phase I agent significantly reduced the chance of grade 3/4 toxicity. Overall survival was not significantly different between the CT and non-CT groups (260 vs 192 days, P=0.47) except for those with liver metastases (228 vs 137 days, P=0.02). Overall tumour response was 4.9% (95% CI: 2.7–7.0%). The PI identified three distinct patient groups with median survival of 321, 257 and 117 days. In conclusion, entry into a phase I trial of a non-CT drug is a safe option for heavily pretreated patients with cancer. The PI generated from these data can estimate the survival probability for patients entering phase I studies.

A phase 1 study of tazarotene in adults with advanced cancer

Tazarotene is an acetylenic retinoid which is metabolised to tazarotenic acid and which binds selectively to the retinoid receptors RARbeta and RARgamma. The safety, toxicity and pharmacokinetics of oral tazarotene were determined over 12 weeks of treatment in 34 patients with advanced cancer. Commonly seen toxicities were mucocutaneous symptoms, musculoskeletal pain and headache. Dose-limiting toxicities were hypercalcaemia, hypertriglyceridaemia and musculoskeletal pain. The maximum tolerated dose of tazarotene in this schedule is 25.2 mg day(-1). Plasma concentrations of tazarotenic acid were found to peak rapidly within 1-3 h of dosing and thereafter declined quickly. The C(max) and AUC values on day 0, and weeks 2 and 4 were similar indicating no drug accumulation. The dose-normalised C(max) and AUC values at different dose levels and different study days appeared to be similar indicating linear pharmacokinetics. No objective responses were seen, although stable disease was seen in six out of eight evaluable patients receiving the three highest dose levels of tazarotene (16.8, 25.2 or 33.4 mg day(-1)). We conclude that oral tazarotene is well tolerated when administered daily for 12 weeks, has a favourable toxicity profile compared with other retinoids and merits further investigation as an anticancer therapy.

Use of positron emission tomography in pharmacokinetic studies to investigate therapeutic advantage in a phase I study of 120-hour intravenous infusion XR5000

PURPOSE

XR5000 (N-[2-(dimethylamino)ethyl]acridine-4-carboxamide) is a topoisomerase I and II inhibitor. Because the cytotoxicity of XR5000 increases markedly with prolonged exposure, we performed a phase I study of weekly XR5000 by 120-hour continuous infusion over 3 weeks.

PATIENTS AND METHODS

Twenty-four patients with advanced solid cancer were treated at seven dose levels (700 to 4,060 mg/m2/120 hrs) for a total of 67 cycles. Three patients underwent positron emission tomography (PET) studies at the maximum-tolerated dose (MTD) to evaluate normal tissue and tumor carbon-11 radiolabeled XR5000 ([11C]XR5000) pharmacokinetics.

RESULTS

The dose-limiting toxicity was National Cancer Institute Common Toxicity Criteria (version 1) grade 4 chest and abdominal pain affecting the single patient receiving 4,060 mg/m2/120 hours, and the MTD was 3,010 mg/m2/120 hours. Other grade 3-4 toxicities, affecting single patients at the MTD, were myelosuppression (grade 4), raised bilirubin, vomiting, and somnolence (all grade 3). There was one partial response (adenocarcinoma of unknown primary); the remainder had progressive disease. [11C]XR5000 distributed well into the three tumors studied by PET. Tumor uptake (maximum concentration or area under the concentration versus time curve [AUC]) was less than in normal tissue in which the tumors were located. Tumor exposure (AUC; mean +/- SD in m2/mL/sec) increased when [(11)C]XR5000 was administered during an infusion of XR5000 (0.242 +/- 0.4), compared with [11C]XR5000 given alone (0.209 +/- 0.04; P <.05), indicating that tumor drug exposure was not saturated [corrected].

CONCLUSION

The recommended dose for XR5000 in phase II studies is 3,010 mg/m2/120 hours. PET studies with 11C-labeled drug were feasible and demonstrated in vivo distribution into tumors. Saturation of tumor exposure was not reached at the MTD.

Low-dose IFN-gamma induces tumor MHC expression in metastatic malignant melanoma

Specific antitumor immune responses require expression of MHC class I or II molecules on tumor cells, and MHC antigen down-regulation is a presumed tumor growth promoting mechanism. Because IFN-gamma up-regulates tumor MHC antigen expression in vitro, in this Phase II trial of an immunologically active dose and schedule we evaluated whether this was the case in vivo. Twenty-three patients with metastatic melanoma were treated with IFN-gamma 100 microg/m(2) s.c. once weekly for a maximum of 6 months. There were three complete responses, now maintained for 53, 36, and 25 months. The remainder had progressive disease. The treatment was well tolerated, with no toxicity exceeding National Cancer Institute Common Toxicity Criteria grade II. Immunohistochemical analysis of tumor biopsies during treatment was performed using monoclonal antibodies to HLA class I (W/632) and class II (CR3/43) monomorphic determinants. HLA class I was down-regulated in 2 of 19 patients pretreatment and up-regulated by IFN-gamma in both. HLA class II was down-regulated pretreatment in 14 of 18 patients and up-regulated by IFN-gamma in 6 (43%). The HLA up-regulation persisted throughout the study. IFN-gamma induced significant but short-lived up-regulation of surrogate markers of monocyte activation (serum neopterin) and class I up-regulation (serum beta-2-microglobulin) in most patients. There was no consistent relationship between surrogate marker up-regulation, tumor antigen up-regulation, and responses. The study shows that the significant immune modulation induced by IFN-gamma does not correlate with tumor responses and that the serum surrogate marker changes do not reflect tumor events. The durable and long-lived responses, clear demonstration of tumor MHC up-regulation, and low toxicity suggest that weekly IFN-gamma 100 microg/m(2) would be a useful addition to chemoimmunotherapeutic regimens.

The human homologue of unc-93 maps to chromosome 6q27 - characterisation and analysis in sporadic epithelial ovarian cancer

BACKGROUND

In sporadic ovarian cancer, we have previously reported allele loss at D6S193 (62%) on chromosome 6q27, which suggested the presence of a putative tumour suppressor gene. Based on our data and that from another group, the minimal region of allele loss was between D6S264 and D6S149 (7.4 cM). To identify the putative tumour suppressor gene, we established a physical map initially with YACs and subsequently with PACs/BACs from D6S264 to D6S149. To accelerate the identification of genes, we sequenced the entire contig of approximately 1.1 Mb. Seven genes were identified within the region of allele loss between D6S264 and D6S149.

RESULTS

The human homologue of unc-93 (UNC93A) in C. elegans was identified to be within the interval of allele loss centromeric to D6S149. This gene is 24.5 kb and comprises of 8 exons. There are two transcripts with the shorter one due to splicing out of exon 4. It is expressed in testis, small intestine, spleen, prostate, and ovary. In a panel of 8 ovarian cancer cell lines, UNC93A expression was detected by RT-PCR which identified the two transcripts in 2/8 cell lines. The entire coding sequence was examined for mutations in a panel of ovarian tumours and ovarian cancer cell lines. Mutations were identified in exons 1, 3, 4, 5, 6 and 8. Only 3 mutations were identified specifically in the tumour. These included a c.452G>A (W151X) mutation in exon 3, c.676C>T (R226X) in exon 5 and c.1225G>A(V409I) mutation in exon 8. However, the mutations in exon 3 and 5 were also present in 6% and 2% of the normal population respectively. The UNC93A cDNA was shown to express at the cell membrane and encodes for a protein of 60 kDa.

CONCLUSIONS

These results suggest that no evidence for UNC93A as a tumour suppressor gene in sporadic ovarian cancer has been identified and further research is required to evaluate its normal function and role in the pathogenesis of ovarian cancer.

RYK, a catalytically inactive receptor tyrosine kinase, associates with EphB2 and EphB3 but does not interact with AF-6

RYK is an atypical orphan receptor tyrosine kinase that lacks detectable kinase activity. Nevertheless, using a chimeric receptor approach, we previously found that RYK can signal via the mitogen-activated protein kinase pathway. Recently, it has been shown that murine Ryk can bind to and be phosphorylated by the ephrin receptors EphB2 and EphB3. In this study, we show that human RYK associates with EphB2 and EphB3 but is not phosphorylated by them. This association requires both the extracellular and cytoplasmic domains of RYK and is not dependent on activation of the Eph receptors. It was also previously shown that AF-6 (afadin), a PDZ domain-containing protein, associates with murine Ryk. We show here that AF-6 does not bind to human RYK in vitro or in vivo. This suggests that there are significant functional differences between human and murine RYK. Further studies are required to determine whether RYK modulates the signaling of EphB2 and EphB3.

Tumour suppressor genes in sporadic epithelial ovarian cancer

Ovarian cancer is the most frequent cause of death from gynaecological malignancies in the western world, and sporadic epithelial ovarian cancer is its most predominant form. The aetiology of sporadic ovarian cancer remains unknown. Genetic studies have enabled a better understanding of the evolution of tumour progression. A major focus of research has been to identify tumour suppressor genes implicated in sporadic ovarian cancer over the past decade. Several tumour suppressor genes have been identified by strategies such as positional cloning and differential expression display. Further research is warranted to understand fully their contribution to the pathogenesis of sporadic ovarian cancer.

Retrospective study of management of uterine sarcomas at Oxford 1990-1998: role of adjuvant treatment

We report a retrospective study of 47 consecutive patients with uterine sarcoma treated at the Churchill Hospital in Oxford between 1990-1998. The mainstay of treatment was surgery with adjuvant chemotherapy and radiotherapy reserved for selected patients with early stage disease. Overall 1 and 2 year survival was 49% and 30% respectively compared with 73% and 55% in the group who received adjuvant chemotherapy/radiotherapy. Median survival was 11 months for the group as a whole compared to 32.9 months in the adjuvant therapy group. This is a retrospective review with small numbers and considerable selection bias, however, given the poor survival of patients with this disease, adjuvant treatment should be considered in future trials of patients with uterine sarcoma.

Functional analysis of discoidin domain receptor 1: effect of adhesion on DDR1 phosphorylation

Discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase (RTK), has been shown to be activated mainly by soluble fibrillar collagen. Unusually, the kinetics of phosphorylation of the receptor is slow, with maximal phosphorylation observed after 90 min. To understand the reasons for slow phosphorylation of the receptor, we examined several cell lines under different conditions. We confirm that endogenous DDR1 is phosphorylated slowly by collagen in adherent T47D and HCT116 cells. In detached and resuspended cells, collagen induced rapid phosphorylation of DDR1. This was further confirmed with a semiadherent cell line (COLO201) and one that grows as a suspension (K562), both of which express endogenous DDR1. Replating K562 on fibronectin to mimic adherent conditions altered the kinetics of phosphorylation from rapid to slow, similar to those of adherent cells. The slow kinetics of phosphorylation in the adherent state was probably not due to cell-cell contacts because EDTA had no major effect. However, pervanadate in the absence of collagen was able to induce strong DDR1 phosphorylation, indicating that a phosphatase may inhibit or delay the phosphorylation of DDR1. Further, downstream signals after phosphorylation of DDR1 by collagen were not transmitted through the classical mitogen-activated protein kinase pathway. In addition, a chimeric TrkA-DDR1 receptor failed to become phosphorylated on stimulation with nerve growth factor (NGF), although it dimerized normally. This is the first RTK whose kinetics of phosphorylation is dependent on cellular context. The interaction of the cells with the matrix, rather than cell-cell contact, is probably responsible for the inhibition of phosphorylation.

Physical and transcript map of the region between D6S264 and D6S149 on chromosome 6q27, the minimal region of allele loss in sporadic epithelial ovarian cancer

We have previously shown a high frequency of allele loss at D6S193 (62%) on chromosomal arm 6q27 in ovarian tumours and mapped the minimal region of allele loss between D6S297 and D6S264 (3 cM). We isolated and mapped a single non-chimaeric YAC (17IA12, 260-280 kb) containing D6S193 and D6S297. A further extended bacterial contig (between D6S264 and D6S149) has been established using PACs and BACs and a transcript map has been established. We have mapped six new markers to the YAC; three of them are ESTs (WI-15078, WI-8751, and TCP10). We have isolated three cDNA clones of EST WI-15078 and one clone contains a complete open reading frame. The sequence shows homology to a new member of the ribonuclease family. The other two clones are splice variants of this new gene. The gene is expressed ubiquitously in normal tissues. It is expressed in 4/8 ovarian cancer cell lines by Northern analysis. The gene encodes for a 40 kDa protein. Direct sequencing of the gene in all the eight ovarian cancer cell lines did not identify any mutations. Clonogenic assays were performed by transfecting the full-length gene in to ovarian cancer cell lines and no suppression of growth was observed.

Phase I and pharmacokinetic study of PKC412, an inhibitor of protein kinase C

PURPOSE

N-Benzoyl staurosporine (PKC412) is a protein kinase C inhibitor with antitumor activity in laboratory models. We determined the toxicity of oral PKC412 administered daily for repeat cycles of 28 days.

PATIENTS AND METHODS

Thirty-two patients with advanced solid cancers were treated at seven dose levels (12.5 to 300 mg daily) for a total of 68 cycles.

RESULTS

The most frequent treatment-related toxicities were nausea, vomiting, fatigue, and diarrhea. At the two top dose levels (225 and 300 mg/d), 15 of 16 patients experienced nausea/vomiting (common toxicity criteria [CTC], version 1), grade 2 in nine of 16 and grade 3 in three of 16 patients; and six of 16 patients developed CTC grade 2 diarrhea. After 1 month of treatment, there were significant reductions in circulating lymphocyte (P <.02) and monocyte (P <.01) counts in patients receiving doses > or = 100 mg/d. Nevertheless, only two patients developed myelosuppression (both grade 2). Of two patients with progressive cholangiocarcinoma, one attained stable disease lasting 4.5 months and one a partial response lasting 4 months. There was a linear relationship between PKC412 dose and area under the curve (0-24 hours) and maximum plasma concentration with marked interpatient variability. The estimated median elimination half-life was 1.6 days (range, 0.9 to 4.0 days), and a metabolite with a median half-life of 36 days was detected. Steady-state PKC412 plasma levels at the top three dose cohorts (150 to 300 mg) were five to 10 times the cellular 50% inhibitory concentration for PKC412 of 0.2 to 0.7 micromol/L.

CONCLUSION

PKC412 can be safely administered by chronic oral therapy, and 150 mg/d is suitable for phase II studies. The pharmacokinetics and lack of conventional toxicity indicate that pharmacodynamic measures may be additionally needed to optimize the drug dose and schedule.

A phase II study of razoxane, an antiangiogenic topoisomerase II inhibitor, in renal cell cancer with assessment of potential surrogate markers of angiogenesis

Renal cell carcinoma (RCC) is an angiogenic tumor resistant to standard cytotoxic chemotherapeutic agents. Although often responsive to immunomodulatory agents including interleukin 2 and IFN-alpha, the overall results in randomized Phase III studies are disappointing with only modest improvements in overall survival. This Phase II study evaluated the efficacy and tolerability of razoxane, an antiangiogenic topoisomerase II inhibitor, in 40 patients (32 men, 8 women; age: range, 31-76 years; median, 58 years) with inoperable RCC. Twenty patients received razoxane 125 mg p.o., twice a day for 5 days each week for 8 weeks (one cycle). This was repeated in patients with stable disease (StD), but was discontinued after 16 weeks if there was no evidence of an objective response. Because minimal toxicity was seen, subsequent patients (n = 20) were treated until progressive disease (PD) was documented. Of 38 evaluable patients, 11 (29%) had StD for a minimum of 4 months, and the remainder had PD. Median overall survival was 7.3 months. Duration of survival was significantly better in patients with StD compared with those with PD (P = 0.003). The effect of treatment on six potential surrogate serum/plasma (vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), urokinase plasminogen activator soluble receptor (uPAsr), E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and von Willebrand's factor (vWF) and two urinary (VEGF and bFGF) markers of angiogenesis was evaluated before and after 1 cycle of treatment. Pretreatment serum VEGF and E-selectin levels above the median value were associated with a poor prognosis. Serum VCAM-1 levels and urinary VEGF levels rose significantly after one cycle in patients with PD but not in those with StD. Serum VEGF, bFGF, VCAM-1 and vWF, plasma uPAsr and urinary bFGF levels were significantly higher in PD patients compared with StD patients before and/or after 1 cycle of treatment. In conclusion, razoxane is an antiangiogenic agent that has minimal toxicity and that requires further evaluation in combination with other active agents in the treatment of RCC. Surrogate serum and urinary markers of angiogenesis may have a role to play in predicting disease response and overall survival in RCC.

Evaluation of the possible protective role of adeno-associated virus type 2 infection in HPV-associated premalignant disease of the cervix

OBJECTIVE

Our objective was to examine the prevalence of adeno-associated virus (AAV) infection in women with normal cervical smears and those with HPV-associated cervical intraepithelial neoplasia (CIN).

METHODS

HPV typing was performed on DNA from cervical smears of 211 women with CIN (CIN 1 = 83, CIN 3 = 128) and 433 healthy women who had a normal cervical smear. HPV typing was performed on all cases and controls using type-specific oligonucleotide primers (HPV 16, 18, 31, 33). AAV DNA was amplified by nested PCR from the same samples. The amplified DNA were separated on 2% agarose gels, blotted, and hybridized to AAV-2 DNA labeled by random priming with [alpha-(32)P]dCTP to confirm specificity of amplification.

RESULTS

A total of 131 cases of CIN were positive for one of the HPV types either alone or in combination. HPV 16 was present in 120 (57%) cases, HPV 18 in 15 (7%), HPV 31 in 27 (13%), and HPV 33 in 15 (7%) and there were multiple HPV types detected in 34 (16%) cases. All of the controls were selected to be negative for HPV. A total of 6/433 (1.4%) control cervical smears and 4/211 (1.9%) of CIN (CIN1 = 2; CIN3 = 2) contained AAV DNA. No correlation between AAV and any clinical feature was observed.

CONCLUSIONS

These results are different from some that have been previously published and suggest that AAV DNA is not frequently present in either normal control cervical samples or cervical intraepithelial neoplasia. This does not support the hypothesis that AAV may be protective against cervical cancer. Further research is necessary to understand the natural history of AAV infection and its role in human disease.

Evaluation of toremifene for reversal of multidrug resistance in renal cell cancer patients treated with vinblastine

PURPOSE

Expression of P-glycoprotein (Pgp), which confers the multidrug resistance (MDR) phenotype, is thought to contribute to the insensitivity of renal cell cancer (RCC) to chemotherapy. The development of Pgp inhibitors for clinical application has been hampered by unacceptable toxicity at doses required to achieve adequate cellular concentration. Toremifene is able to reverse MDR and sensitise RCC to vinblastine in vitro. However, in vivo toremifene is tightly bound to serum proteins, in particular the acute phase protein alpha1-acid glycoprotein (AAG), which may limit tissue availability. In this phase I-II study we assessed the tolerability of short courses of high dose toremifene in combination with vinblastine and evaluated the key determinants of MDR reversal in vivo.

METHODS

Twenty-seven patients with metastatic RCC received escalating doses of oral toremifene for 3 days every 2 weeks in combination with vinblastine 6 mg/m2 i.v. on day 3 of each cycle. The serum concentration of toremifene, its metabolites and AAG were measured and the effect of patients' serum on inhibition of Pgp in vitro was determined.

RESULTS

Twenty-six patients were evaluable for response. Eight patients (31%) had stable disease and 18 patients (69%) progressive disease. The mean serum concentration of toremifene at 780 mg daily for 3 days was 7.82 microM [standard deviation (SD) 2.48, range 2.50 to 14.70], which exceeds that known to reverse MDR in vitro. The serum concentration of the major metabolite of toremifene, N-demethyltoremifene, which also reverses MDR, was 5.13 microM (SD 1.78, range 1.80 to 9.00). In 60% of patients the pre-treatment AAG concentration was above that known to block the effects of toremifene in vitro. However, addition of serum from patients on toremifene to MCF-7 adr cells in vitro inhibited Pgp-mediated efflux of rhodamine 123.

CONCLUSIONS

We have shown that short course, high-dose toremifene in combination with vinblastine is generally well tolerated and that the concentration of toremifene required to reverse MDR in vitro is achievable in vivo.