The ATAC adjuvant breast-cancer trial: six-year results of the endometrial subprotocol.

Postmenopausal women with localised, early breast cancer (n = 285) were enrolled in a prospective subprotocol of the 'arimidex, tamoxifen, alone or in combination' (ATAC) trial to assess gynaecological abnormalities arising during treatment with anastrozole (1 mg/day) or tamoxifen (20 mg/day). After 6 years' follow-up, there appeared to be non-significantly fewer endometrial abnormalities with anastrozole than with tamoxifen (12.4% vs 20.2%, odds ratio 0.52; 95% confidence intervals 0.20, 1.32; p = 0.17). The time to first endometrial abnormality was non-significantly longer for patients receiving anastrozole compared with tamoxifen (hazard ratio 0.57; 95% confidence intervals 0.26, 1.22; p = 0.15), with most abnormalities occurring within the first year of treatment. Fewer patients treated with anastrozole appeared to require medical intervention for endometrial abnormalities, compared with patients on tamoxifen. This study showed that there was no significant difference in endometrial pathology between anastrozole and tamoxifen treatment groups.

Phase II study of gefitinib in combination with docetaxel as first-line therapy in metastatic breast cancer.

We have evaluated the activity and safety of gefitinib, a small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, in combination with docetaxel as first-line treatment of women with metastatic breast cancer (MBC). In total, 41 patients with MBC were enrolled in a first-line combination therapy study with oral gefitinib (250 mg day(-1)) and intravenous docetaxel (75 mg m(-2), the first 14 patients; or 100 mg m(-2), the following 27 patients, on day 1 of a 3-week cycle). Out of 41 patients, 38 received at least one cycle of therapy. There were no differences in activity or tolerability between the two docetaxel doses. G3/4 toxicities were neutropenia (49%), diarrhoea (10%), acne-like rash (5%), and anaemia (2%). Complete plus partial responses (CR+PR) were observed in 22 out of 41 patients with a 54% response rate (95% confidence interval (CI) 45-75%). The 22 patients that achieved a response following six cycles of docetaxel plus gefitinib continued gefitinib monotherapy (median duration, 24 weeks; range, 2-108+ weeks). Two patients with PR following combination therapy achieved a CR during gefitinib monotherapy. Complete plus partial responses correlated with oestrogen receptor (ER) status, since they occurred in 19 out of 27 (70%) patients with ER-positive tumours as compared to three out of 14 (21%) patients with ER-negative tumours (P=0.01).

The ATAC ('Arimidex', Tamoxifen, Alone or in Combination) adjuvant breast cancer trial: first results of the endometrial sub-protocol following 2 years of treatment.

BACKGROUND: Tamoxifen treatment results in a doubling of the risk of endometrial cancer after 1-2 years of treatment and a quadrupling after 5 years. Anastrozole, a third-generation aromatase inhibitor, with superior efficacy to tamoxifen, may also offer tolerability benefits in terms of effects on the endometrium. METHODS AND RESULTS: A sub-protocol of the ATAC trial compared the incidence/type of intrauterine changes following treatment with these agents in a subgroup of patients (n = 285) from the main trial. After 2 years anastrozole treatment, endometrial thickness remained

Modulation of 5-fluorouracil as adjuvant systemic chemotherapy in colorectal cancer: the IGCS-COL multicentre, randomised, phase III study.

The aims of this multicentre, randomised phase III trial were to evaluate: (1) the role of levamisol (LEV); and (2) the role of folinic acid (FA), added to 5-fluorouracil (5FU) in the adjuvant treatment of colorectal cancer. Patients with histologically proven, radically resected stage II or III colon or rectal cancer were eligible. The study had a 2x2 factorial design with four treatment arms: (a) 5FU alone, (b) 5FU+LEV, (c) 5FU+FA, (d) 5FU+LEV+FA, and two planned comparisons, testing the role of LEV and of FA, respectively. From March 1991, to September 1998, 1327 patients were randomised. None of the two comparisons resulted in a significant disease-free (DFS) or overall (OAS) survival advantage. The hazard ratio (HR) of relapse was 0.89 (95% confidence intervals (CI): 0.73-1.09) for patients receiving FA and 0.99 (95% CI 0.80-1.21) for those receiving LEV; corresponding HRs of death were 1.02 (95% CI: 0.80-1.30) and 0.94 (95% CI 0.73-1.20). Nonhaematological toxicity (all grade vomiting, diarrhoea, mucositis, congiuntivitis, skin, fever and fatigue) was significantly worse with FA, while all other toxicities were similar. In the present trial, there was no evidence that the addition of FA or LEV significantly prolongs DFS and OAS of radically resected colorectal cancer patients.

A phase II study of biweekly oxaliplatin plus infusional 5-fluorouracil and folinic acid (FOLFOX-4) as first-line treatment of advanced gastric cancer patients.

The aim of the study was to assess the toxicity and the clinical activity of biweekly oxaliplatin in combination with infusional 5-fluorouracil (5-FU) and folinic acid (FA) administered every 2 weeks (FOLFOX-4 regimen) in patients with advanced gastric cancer (AGC). A total of 61 previously untreated AGC patients were treated with oxaliplatin 85 mg m(-2) on day 1, FA 200 mg m(-2) as a 2 h infusion followed by bolus 5-FU 400 mg m(-2) and a 22 h infusion of 5-FU 600 mg m(-2), repeated for 2 consecutive days every 2 weeks. All patients were assessable for toxicity and response to treatment. Four (7%) complete responses and 19 partial responses were observed (overall response rate, 38%). Stable disease was observed in 22 (36%) patients, with progressive disease in the other six (10%) patients. Median time to progression (TTP) and median overall survival (OS) were 7.1 and 11.2 months, respectively. National Cancer Institute Common Toxicity Criteria grade 3 and 4 haematologic toxicities were neutropenia, anaemia and thrombocytopenia in 36, 10 and 5% of the patients, respectively. Grade 3 peripheral neuropathy was recorded in three (5%) patients. FOLFOX-4 is an active and well-tolerated chemotherapy. Response rate (RR), TTP and OS were comparable with those of other oxaliplatin-based regimens, suggesting a role for this combination in gastric cancer.

Expression of biomarkers modulating prostate cancer progression: implications in the treatment of the disease.

OBJECTIVES: To determine whether COX-2, bcl-2 and neoangiogenesis are related to human prostate cancer relapse after definitive surgical treatment and progression toward androgen independence and to evaluate the association between the patterns of these tumoral biomarkers and other standard clinico-pathological parameters (such as Gleason score, PSA, TNM stage). MATERIALS AND METHODS: We retrospectively analyzed the records on 126 prostate cancer samples from patients treated at our University Hospital from 1995 to 2002. The 72 patients with clinically localized disease (group 1) had undergone radical prostatectomy. Another 54 patients (group 2) had metastatic androgen-independent disease. Archived material relating to the subjects was then immunostained for bcl-2, COX-2 and CD-31, using an anti-bcl-2 monoclonal primary antibody, an anti-COX-2 polyclonal rabbit antibody and an anti-CD-31 monoclonal mouse antibody to evaluate neoangiogenesis (MVD, microvessel density). RESULTS: We found that bcl-2, COX-2 and MVD expression increased from group 1 to group 2. The intergroup difference was significant only for high MVD (P < 0.05). On the other hand, high MVD, high bcl-2 and high COX-2 expression was correlated with a higher PSA level (P < 0.01), whereas only a high MVD was also related with Gleason score (P < 0.05). We used univariate analysis to evaluate the prognostic impact of biologic and clinico-pathologic parameters on the disease-free-survival of 72 patients treated by radical prostatectomy. A total of 30 patients (41.6%) experienced biochemical relapse; bcl-2, COX-2 and MVD significantly correlated with disease relapse in these patients. In fact, we observed disease relapse in 24/45 (53%) with high bcl-2 expression, in 15/21 (71%) with a high MVD count and finally, in 30/58 (52%) with high COX-2 expression. Finally, PSA value and Gleason score were the only two biologic markers significantly associated to disease relapse in a multivariate analysis. CONCLUSIONS: Our results strongly support a role for bcl-2, COX-2 and angiogenesis in the development and progression of prostate cancer. Of course, we are aware of the small sample size considered in our study. Further investigations would better clarify the prognostic and therapeutic implications of these findings.

A randomised factorial trial of sequential doxorubicin and CMF vs CMF and chemotherapy alone vs chemotherapy followed by goserelin plus tamoxifen as adjuvant treatment of node-positive breast cancer.

The sequential doxorubicin --> CMF (CMF=cyclophosphamide, methotrexate, fluorouracil) regimen has never been compared to CMF in a randomised trial. The role of adding goserelin and tamoxifen after chemotherapy is unclear. In all, 466 premenopausal node-positive patients were randomised to: (a) CMF x 6 cycles (CMF); (b) doxorubicin x 4 cycles followed by CMF x 6 cycles (A --> CMF); (c) CMF x 6 cycles followed by goserelin plus tamoxifen x 2 years (CMF --> GT); and (d) doxorubicin x 4 cycles followed by CMF x 6 cycles followed by goserelin plus tamoxifen x 2 years (A --> CMF --> GT). The study used a 2 x 2 factorial experimental design to assess: (1) the effect of the chemotherapy regimens (CMF vs A --> CMF or arms a+c vs b+d) and (2) the effect of adding GT after chemotherapy (arms a+b vs c+d). At a median follow-up of 72 months, A --> CMF as compared to CMF significantly improved disease-free survival (DFS) with a multivariate hazard ratio (HR)=0.740 (95% confidence interval (CI): 0.556-0.986; P=0.040) and produced a nonsignificant improvement of overall survival (OS) (HR=0.764; 95% CI: 0.489-1.193). The addition of GT after chemotherapy significantly improved DFS (HR=0.74; 95% CI: 0.555-0.987; P=0.040), with a nonsignificant improvement of OS (HR=0.84; 95% CI: 0.54-1.32). A --> CMF is superior to CMF. Adding GT after chemotherapy is beneficial for premenopausal node-positive patients.

The ATAC ('Arimidex', Tamoxifen, Alone or in Combination) adjuvant breast cancer trial: baseline endometrial sub-protocol data on the effectiveness of transvaginal ultrasonography and diagnostic hysteroscopy.

BACKGROUND: The 'Arimidex', Tamoxifen, Alone or in Combination (ATAC) trial is a randomized, double-blind trial comparing anastrozole ('Arimidex'), alone or in combination with tamoxifen, relative to tamoxifen alone as 5 year adjuvant treatment for post-menopausal women with early breast cancer. Since tamoxifen is associated with endometrial pathology, the ATAC endometrial sub-protocol was initiated to establish the background prevalence of intrauterine pathology, and to assess prospectively the incidence and nature of intrauterine changes following endocrine therapy. Another aim was to provide data from which advice could be generated on the best endometrium screening method for patients receiving tamoxifen. METHODS: Patients underwent endometrial assessments at entry to the sub-protocol. The baseline investigations comprised transvaginal ultrasound scanning (TVUS), a hysteroscopy and an endometrial biopsy. RESULTS: A total of 285 gynaecologically asymptomatic women from 31 centres in 10 countries entered the endometrial sub-protocol. The mean uterine volume was 47.7 cm3. The median endometrial thickness overall was 3 mm. Twenty-four histologically confirmed, pathological changes were observed. Twenty-three pathologies were confirmed by TVUS, and 21 were identified by hysteroscopy and confirmed by histopathology. Women with or without intrauterine pathology had median endometrial thickness of 5 and 3 mm respectively. CONCLUSIONS: The presence of pathology was associated with increased endometrial thickness. The relative sensitivity and specificity of hysteroscopy and endometrial thickness for the diagnosis of endometrial pathology was comparable to other studies. If screening of the endometrium prior to treatment is appropriate, this study supports the use of an endometrial thickness of 3 mm, as assessed by TVUS, as a threshold for needing further investigation. This study demonstrates that if the endometrial thickness is >3 mm, hysteroscopy and biopsy is the optimal method of detecting intrauterine pathology in women with breast cancer who are about to commence endocrine treatment.

Targeting c-erbB2 and other receptors of the c-erbB family: rationale and clinical applications.

The c-erbB family of receptors includes four distinct receptors, namely c-erb B1, 2, 3 and 4 (HER1, 2, 3 and 4, respectively). Trastuzumab (T) is a recombinant humanized anti-HER2 monoclonal antibody that binds the extracellular domain of the receptor and blocks intracellular signalling. In clinical studies of T, either alone or in combination with chemotherapy, in HER2 overexpressing metastatic breast cancer patients, a significant benefit was obtained--improved response rates and survival, when T was combined with chemotherapy. Several trials of adjuvant T, either singly or in combination with chemotherapy, are in progress in early breast cancer patients. Pertuzumab defines a new class of HER2 inhibitors, "dimerization inhibitors" that block both homo- and hetero-dimerization of HER2. In preclinical studies pertuzumab is inhibitory to breast, prostate and non small cell lung cancer cell lines, both over and non overexpressing HER2. In phase I clinical trials pertuzumab has shown activity in a number of human cancers. A phase II program is in progress.

The ATAC adjuvant breast cancer trial in postmenopausal women: baseline endometrial subprotocol data.

OBJECTIVE: The ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial is a randomised, double-blind trial comparing 'Arimidex' (anastrozole), alone or in combination with tamoxifen, relative to tamoxifen alone as a five year adjuvant treatment for postmenopausal women with early breast cancer. Because tamoxifen is associated with endometrial pathology, the ATAC endometrial subprotocol was initiated to establish the background prevalence of pathology, and to assess prospectively the incidence and nature of intrauterine changes before and following endocrine therapy. SETTING: International. POPULATION AND STUDY DESIGN: Two hundred and eighty-five women entered the subprotocol: the mean age was 60 years (range 44-80 years); 113 women (40%) had taken hormone replacement therapy prior to randomisation, and 238 women were parous (84%). The age at onset of the menopause was 32-58 years, with the majority becoming menopausal between 46 and 55 years of age. Two hundred and seventy-two women had a hysteroscopy before they commenced trial medication. Hysteroscopy was performed successfully in 265 women. In six women, failure of hysteroscopy at baseline led to withdrawal from the study. Three of the women who withdrew had a pipelle biopsy taken. Therefore, the total number of endometrial biopsies at baseline was 268. MAIN OUTCOME MEASURES: To assess the demographic characteristics of women entering the endometrial subprotocol and their hysteroscopic and histological findings before commencing trial medication. RESULTS: At hysteroscopy, there was a diagnosis of endometrial polyps in 34 women (13%), fibroids in 16 women (6%) and one case of suspicious endometrium, which was confirmed as a polyp on histology. Only 21 of the 34 polyps seen hysteroscopically were proven histologically (62% accuracy of hysteroscopy). Final histology found the prevalence of endometrial diagnostic categories as follows: 123 inactive endometrium (46%), 20 benign polyps (7%), 17 secretory endometrium (6%), 7 proliferative endometrium (3%), 3 atypical hyperplasia (2 in a polyp), 1 simple hyperplasia (in a polyp) and 1 fibroid. The remaining women had pipelle samples with insufficient tissue obtained, indicating a normal endometrial cavity. CONCLUSION: This is the first study of such size in gynaecologically asymptomatic breast cancer patients. This paper describes the findings in individual patients before any trial treatment was given. In this baseline group, 82% (219/268) of women had a normal endometrial cavity; 18% (49/268) had endometrial activity (proliferative or secretory endometrium in 9%) or an intracavity abnormality (hyperplasia, polyps and a fibroid in 9%). In total, 36% of biopsies had insufficient tissue for diagnosis, which in combination with a normal hysteroscopy was classed as normal. The appearance of a polyp hysteroscopically in this group was not proven histologically in approximately 40% of cases. The development of uterine pathology over time in the ATAC study will subsequently be assessed against the findings of this baseline paper.

Recombinant IFN-alpha2b treatment activates poly (ADPR) polymerase-1 (PARP-1) in KB cancer cells.

In the present paper, we investigated the relationship between the growth inhibitory effects of recombinant interferon-alpha2b (rIFN-alpha2b) and poly (ADPR) polymerase-1 (PARP-1) activity in the human squamous KB cancer cell line. Growth inhibition of the KB cells mediated by 1000 IU/ml of rIFN-alpha2b was accompanied by a transient rise in PARP-1 specific activity 24 h after rIFN-alpha2b treatment, confirmed by both the increase of intracellular poly (ADP-ribose) content and the PARP-1 auto-modification level. At longer times of incubation, the onset of apoptosis accompanied KB cell growth inhibition, as demonstrated by both flow cytometry and western-blotting analysis showing an 89 kDa apoptotic fragment of PARP-1. Moreover, pretreatment of the cells with the PARP-1 inhibitor, 3-aminobenzamide (3-ABA), at non-cytotoxic concentrations (1 mM), reduced the cell-growth inhibition, cell-cycle perturbation and apoptosis caused by rIFN-alpha2b. Taken together, these results strongly suggest that PARP-1 may be directly involved in the effects of rIFN-alpha2b in the KB cancer cell line.

EGF activates an inducible survival response via the RAS-> Erk-1/2 pathway to counteract interferon-alpha-mediated apoptosis in epidermoid cancer cells.

The mechanisms of tumor cell resistance to interferon-alpha (IFNalpha) are at present mostly unsolved. We have previously demonstrated that IFNalpha induces apoptosis on epidermoid cancer cells and EGF antagonizes this effect. We have also found that IFNalpha-induced apoptosis depends upon activation of the NH(2)-terminal Jun kinase-1 (Jnk-1) and p(38) mitogen-activated protein kinase, and that these effects are also antagonized by EGF. At the same time, IFNalpha increases the expression and function of the epidermal growth factor receptor (EGF-R). Here we report that the apoptosis induced by IFNalpha occurs together with activation of caspases 3, 6 and 8 and that EGF also antagonizes this effect. On the basis of these results, we have hypothesized that the increased EGF-R expression and function could represent an inducible survival response that might protect tumor cells from apoptosis caused by IFNalpha via extracellular signal regulated kinase 1 and 2 (Erk-1/2) cascades. We have found an increased activity of Ras and Raf-1 in IFNalpha-treated cells. Moreover, IFNalpha induces a 50% increase of the phosphorylated isoforms and enzymatic activity of Erk-1/2. We have also demonstrated that the inhibition of Ras activity induced by the transfection of the dominant negative Ras plasmid RASN17 and the inhibition of Mek-1 with PD098059 strongly potentiates the apoptosis induced by IFNalpha. Moreover, the selective inhibition of this pathway abrogates the counteracting effect of EGF on the IFNalpha-induced apoptosis. All these findings suggest that epidermoid tumor cells counteract the IFNalpha-induced apoptosis through a survival pathway that involves the hyperactivation of the EGF-dependent Ras->Erk signalling. The selective targeting of this pathway appears to be a promising approach in order to enhance the antitumor activity of IFNalpha.

Second-line chemotherapy with a hybrid-alternating regimen of bolus 5FU modulated by methotrexate and infusional 5FU modulated by folinic acid in patients with metastatic colorectal cancer pretreated with 5FU. A phase 2 study.

BACKGROUND AND AIM: In vitro, methotrexate (MTX) is the best modulator for bolus 5-fluorouracil (5FU), whereas folinic acid (FA) is the best for continuous infusion. We evaluated the effect of 5FU modulated by both MTX (bolus administration) and FA (continuous infusion) as second-line treatment of patients with metastatic colorectal cancer. PATIENTS AND METHODS: Entry criteria were: at least one 5FU-based chemotherapy regimen as first-line treatment for metastatic disease, or progression within twelve months after 5FU-containing adjuvant therapy. Treatment schedule: MTX 200 mg/m2 i.v. days 1 and 15; 5FU 600 mg/m2 i.v. bolus, days 2 and 16; 5FU 200 mg/m2 i.v. continuous infusion for 21 days, starting on day 29; FA 20 mg/m2 i.v. bolus weekly during the three weeks of 5FU infusion. Cycles were repeated every 56 days. The primary end-point was tumour control rate, including partial responses and stabilizations. RESULTS: 34/35 patients enrolled were evaluable for response. Five (14.7%) had a partial response, 13 (38.2%) disease stabilization, and 16 (47.1%) progressed; tumour control rate was 52.9%. Median TTP was 5.8 months (95% CI 4.03-7.83); 29 patients had died. Median OAS was 15.9 months (95% CI 8.8-21.9). Toxicity was mild. CONCLUSIONS: The regimen constituted by 5FU modulated by MTX (bolus administration) and FA (continuous infusion) is active as second-line treatment of metastatic colorectal cancer.

Preclinical and phase I study of oxaliplatin and topotecan in combination in human cancer.

BACKGROUND: DNA damage caused by platinum agents is frequently followed by induction of topoisomerase I, providing a rationale for use of platinum-based compounds with topoisomerase I inhibitors. MATERIALS AND METHODS: We studied the effect of a sequential schedule of oxaliplatin on day I and topotecan on days 2-5, in human colon and ovarian cancer cells in vitro, in nude mice bearing human cancer xenografts and finally in cancer patients in a phase I trial. RESULTS: We demonstrated a supra-additive effect of this combination on inhibition of colony formation and induction of apoptosis in vitro. We then demonstrated that the two agents in combination markedly inhibit tumor growth in nude mice. We translated these results into a clinical setting, conducting a phase I study in cancer patients with oxaliplatin 85 mg/m2 on day 1 and topotecan at doses escalating from 0.5 to 1.5 mg/m2 on days 2-5. Sixty cycles of treatment were administered to 18 patients affected prevalently by ovarian and colorectal cancer. Combination with topotecan 1.5 mg/m2 caused a dose-limiting toxicity. Therefore the maximum tolerated dose of topotecan was 1.25 mg/m2, at which six patients experienced a mild hematological and gastrointestinal toxicity. We also obtained evidence of clinical activity, particularly in ovarian cancer. CONCLUSIONS: Our results provide a solid biological and clinical rationale for a phase II trial at the recommended doses of oxaliplatin 85 mg/m2 and topotecan 1.25 mg/m2, possibly in ovarian cancer patients.

Oral administration of a novel taxane, an antisense oligonucleotide targeting protein kinase A, and the epidermal growth factor receptor inhibitor Iressa causes cooperative antitumor and antiangiogenic activity.

PURPOSE: Protein kinase A type I (PKAI) and the epidermal growth factor receptor (EGFR) play a role in neoplastic transformation and interact with each other in transducing mitogenic signals. We developed different PKAI and EGFR inhibitors, demonstrating their cooperation with cytotoxic drugs and the therapeutic potential of the combined blockade of PKAI and EGFR. In this study, we investigated the effect of orally active PKAI and EGFR inhibitors in combination with a novel taxane. EXPERIMENTAL DESIGN: We combined a hybrid PKAI antisense oligonucleotide sequence (AS-PKAI), the EGFR inhibitor ZD1839 (Iressa), and the taxane IDN5109, studying their effect on human cancer growth, apoptosis, and angiogenesis and measuring vascular endothelial growth factor (VEGF) expression and vessel formation in vitro and after oral administration in nude mice. RESULTS: We demonstrated cooperative growth inhibitory and proapoptotic effects and inhibition of VEGF expression with any combination of two drugs and a marked synergistic effect when all three agents were combined. Oral administration of AS-PKAI, ZD1839, and IDN5109 in combination to nude mice caused a remarkable antitumor effect with no histological evidence of tumors in 50% of mice 5 weeks after treatment withdrawal, accompanied by complete suppression of vessel formation and VEGF expression. CONCLUSION: This is the first demonstration of the cooperative antitumor and antiangiogenic activity of three novel agents that block multiple signaling pathways after oral administration. Because all agents are under clinical evaluation in cancer patients, our results provide a rationale to translate this feasible therapeutic strategy in a clinical setting.

Combined blockade of protein kinase A and bcl-2 by antisense strategy induces apoptosis and inhibits tumor growth and angiogenesis.

Protein kinase A type I (PKAI) plays a key role in neoplastic transformation, conveys mitogenic signals from different sources, and is overexpressed in the majority of human tumors. Inhibition of PKAI by different tools results in cancer-cell growth inhibition in vitro and in vivo. We and others have recently shown that a novel class of mixed-backbone oligonucleotides targeting the PKAI subunit RIalpha exhibits improved pharmacokinetic properties and antitumor activity accompanied by increased apoptosis in several human cancer types in vitro and in vivo. The role of bcl-2 in the control of apoptosis has been widely documented, and the inhibition of bcl-2 expression and function may have important therapeutic implications. In fact, oligonucleotides antisense bcl-2 have shown antitumor activity in animal models and have successfully completed early clinical trials. Recent studies have demonstrated a direct role of PKA in the regulation of the bcl-2-dependent apoptotic pathway. Therefore, we have investigated the combined blockade of PKA and bcl-2 by antisense strategy as a potential therapeutic approach. The novel hybrid DNA/RNA mixed-backbone oligonucleotide antisense RIalpha (AS RIalpha) in combination with the antisense bcl-2 (AS bcl-2), cooperatively inhibited bcl-2 expression and soft agar growth and induced apoptosis in different human cancer cell lines. p.o. administration of AS RIalpha in combination with i.p. AS bcl-2 caused a marked antitumor effect and a significant prolongation of survival in nude mice bearing human colon cancer xenografts. Moreover, histochemical analysis of tumor specimens showed inhibition of RIalpha and Ki67 expression, inhibition of angiogenesis, and parallel induction of apoptosis in vivo. The results of our study imply an interaction between the PKA and bcl-2 signaling pathways and, because both antisenses have now entered Phase II trials, provide the rationale to translate this novel therapeutic strategy in a clinical setting.

Antisense oligonucleotides targeting the epidermal growth factor receptor inhibit proliferation, induce apoptosis, and cooperate with cytotoxic drugs in human cancer cell lines.

We have constructed a series of 22 phosphorothioate 20-mer antisense oligonucleotides directed against different regions of the human (EGFR) mRNA. Treatment with EGFR antisense oligonucleotides showed a dose-dependent inhibition of human GEO colon cancer cell growth in soft agar. Western blot analysis demonstrated a significant reduction in EGFR expression after treatment with each EGFR antisense oligonucleotide. The ability to inhibit GEO anchorage-independent growth, however, varied among the EGFR antisense sequences with an IC(50) ranging between 0.5 and 3.5 microM. Two of these antisense oligonucleotides targeting the regions between 2457-2476 and 614-4633 bases of the human EGFR mRNA have been modified as hybrid DNA/RNA mixed backbone oligonucleotides (MBO) to examine their anticancer properties in vivo. The 2 EGFR antisense MBOs retained the same biological properties of the fully phosphorothioate EGFR antisense oligonucleotides targeting the same EGFR mRNA sequences, such as blocking EGFR synthesis, inhibiting cell growth and enhancing programmed cell death in human cancer cell lines that express functional EGFRs. Furthermore, a potentiation in the growth inhibitory effect on GEO cancer cells was observed after treatment with these EGFR antisense MBOs in combination with cytotoxic drugs, including cisplatin, doxorubicin, paclitaxel, or topotecan. These results show the antiproliferative activity of specific EGFR antisense oligonucleotides and allow to identify novel EGFR antisense MBOs that deserve further evaluation as potential selective anticancer agents alone or in combination with cytotoxic drugs in human carcinomas that express functional EGFRs.

Inhibition of growth factor production and angiogenesis in human cancer cells by ZD1839 (Iressa), a selective epidermal growth factor receptor tyrosine kinase inhibitor.

The transforming growth factor-alpha/epidermal growth factor receptor (TGF-alpha-EGFR) autocrine pathway, which is involved in the development and the progression of human epithelial cancers, controls, in part, the production of angiogenic factors. These angiogenic factors, including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), are secreted by cancer cells to stimulate normal endothelial cell growth through paracrine mechanisms. ZD1839 (Iressa) is a p.o.-active, selective EGFR-tyrosine kinase inhibitor (TKI) in clinical trials in cancer patients. In this study, we evaluated the antiangiogenic and antitumor activity of ZD1839 in human colon (GEO, SW480, and CaCo2), breast (ZR-75-1 and MCF-7 ADR), ovarian (OVCAR-3), and gastric (KATO III and N87) cancer cells that coexpress TGF-alpha and EGFR. ZD1839 treatment determined a dose- and time-dependent growth inhibition accompanied by the decrease of VEGF, bFGF and TGF-alpha production in vitro. Treatment of immunodeficient mice bearing well-established, palpable GEO xenografts with ZD1839 determined a cytostatic dose-dependent tumor growth inhibition. Immunohistochemical analysis of GEO tumor xenografts after ZD1839 treatment revealed a significant dose-dependent reduction of TGF-alpha, bFGF, and VEGF expression in cancer cells and of neoangiogenesis, as determined by microvessel count. Furthermore, the antitumor activity of ZD1839 was potentiated in combination with the cytotoxic drug paclitaxel in GEO tumor xenografts. Tumor regression was observed in all mice after treatment with ZD1839 plus paclitaxel, and it was accompanied by a significant potentiation in inhibition of TGF-alpha, VEGF, and bFGF expression with a few or no microvessels. Furthermore, 6 of 16 mice bearing well-established, palpable GEO xenografts had no histological evidence of GEO tumors at the end of treatment with ZD1839 plus paclitaxel. These results demonstrate that the antitumor effect of ZD1839 is accompanied by inhibition in the production of autocrine and paracrine growth factors that sustain autonomous local growth and facilitate angiogenesis, and that this effect can be potentiated by the combined treatment with certain cytotoxic drugs, such as paclitaxel.

Antitumor activity of combined treatment of human cancer cells with ionizing radiation and anti-epidermal growth factor receptor monoclonal antibody C225 plus type I protein kinase A antisense oligonucleotide.

Recent studies have suggested that selective inhibition of mitogenic pathways may improve the antitumor activity of ionizing radiation. The epidermal growth factor receptor (EGFR) is overexpressed and is involved in autocrine growth control in the majority of human carcinomas. Protein kinase A type I (PKAI) plays a key role in neoplastic transformation and is overexpressed in cancer cells in which an EGFR autocrine pathway is activated. We used two specific inhibitors of EGFR and PKAI that are under clinical evaluation in cancer patients: C225, an anti-EGFR chimeric human-mouse monoclonal antibody (MAb); and a mixed-backbone antisense oligonucleotide targeting the PKAI RIalpha subunit (PKAI AS). We tested in human colon cancer (GEO) and ovarian cancer (OVCAR-3) cell lines the antiproliferative activity of MAb C225 and/or PKAI AS in combination with ionizing radiation. In vivo antitumor activity was evaluated in nude mice bearing established GEO xenografts. Dose-dependent inhibition of soft agar growth was observed in both cancer cell lines with ionizing radiation, C225, or PKAI AS oligonucleotide. A cooperative antiproliferative effect was obtained when cancer cells were treated with ionizing radiation followed by MAb C225 or PKAI AS oligonucleotide. This effect was observed at all doses tested in both GEO and OVCAR-3 cancer cell lines. A combination of the three treatments at the lowest doses produced an even greater effect than that observed when two modalities were combined. Treatment of mice bearing established human GEO colon cancer xenografts with radiotherapy (RT), MAb C225, or PKAI AS oligonucleotide produced dose-dependent tumor growth inhibition that was reversible upon treatment cessation. A potentiation of the antitumor activity was observed in all mice treated with RT in combination with MAb C225 or PKAI AS oligonucleotide. Long-term GEO tumor growth regression was obtained following treatment with ionizing radiation in combination with MAb C225 plus PKAI AS oligonucleotide, which produced a significant improvement in survival compared with controls (P < 0.001), the RT-treated group (P < 0.001), or the group treated with MAb C225 plus PKAI AS oligonucleotide (P < 0.001). All mice of the RT + MAb C225 + PKAI AS group were alive 26 weeks after tumor cell injection. Furthermore, 50% of mice in this group were alive and tumor-free after 35 weeks. This study provides a rationale for evaluating in cancer patients the combination of ionizing radiation and selective drugs that block EGFR and PKAI pathways.

A novel MDM2 anti-sense oligonucleotide has anti-tumor activity and potentiates cytotoxic drugs acting by different mechanisms in human colon cancer.

MDM2 is over-expressed in several human tumors. Its product is a negative-feedback regulator of p53, which interferes with the control of cell proliferation and apoptosis, interacting not only with p53 but also with retinoblastoma (Rb) and E2F. Moreover, mutations in the ARF-Ink4a locus may also allow MDM2 to override p53 functions. In this study, we have used a novel oligonucleotide anti-sense MDM2, with mixed-backbone structure and demonstrate that it causes inhibition of MDM2 expression, induction of both p53 and p21/WAF1 expression and a dose-dependent, growth-inhibitory effect in human GEO colon-cancer cells. We also show that anti-sense MDM2 has a co-operative growth-inhibitory effect with different classes of cytotoxic drugs acting by different mechanisms. Moreover, anti-sense MDM2 induces apoptosis and markedly enhances the apoptotic activity of different cytotoxic drugs. Finally, we show that anti-sense MDM2 has anti-tumor activity in vivo in nude mice bearing GEO xenografts and potentiates the anti-tumor effect of cytotoxic drugs. Indeed, despite the short treatment period, the combination of anti-sense MDM2 and cytotoxic drugs causes a marked delay in tumor growth and prolongation of mice survival, lasting several months after treatment cessation. The anti-tumor effect is associated with inhibition of MDM2 expression in tumor specimens of animals treated with anti-sense MDM2, alone or in combination with a cytotoxic drug. Our results provide the rationale for development of a novel mixed-backbone anti-sense MDM2 into a clinical setting in therapeutic combination strategies with conventional cytotoxic drugs.