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Biomedical subjects

S De Placido

Publications and source records attributed to S De Placido.

At least 19 recordsLinked to original sources
PubMed2006

Weekly docetaxel and capecitabine is not effective in the treatment of advanced gastric cancer: a phase II study.

BACKGROUND: Capecitabine and docetaxel have demonstrated preclinical antitumor synergy and activity in advanced gastric cancer. We assessed the clinical activity and the toxicity of weekly docetaxel in combination with capecitabine in untreated patients with advanced gastric cancer. PATIENTS AND METHODS: A total of 38 patients were treated with docetaxel 36 mg/m2 on days 1, 8, and 15 i.v., plus capecitabine, 625 mg/m2 bid per os on days 5 to 18 repeated every 4 weeks. RESULTS: All patients were assessable for response to treatment and for toxicity. Major responses were observed in eight patients (21%), with three patients achieving a CR (7.8%) and five showing a PR (13%). The median time to progression was 5.4 months and the overall survival was 7.7 months. The safety profile of this schedule was acceptable with a low rate of myelossuppression, diarrhoea and hand-foot syndrome. CONCLUSIONS: The combination of docetaxel and capecitabine at the doses and schedule investigated in this study is safe, but does not show significant activity in untreated patients with advanced gastric cancer.

Adenocarcinoma↗
PubMed2006

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).

Adult↗
PubMed2005

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.

Adult↗
PubMed2005

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.

Adenocarcinoma↗
PubMed2005

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.

Adult↗
PubMed2005

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.

Cyclooxygenase 2↗
PubMed2005

Targeting HER2 as a therapeutic strategy for breast cancer: a paradigmatic shift of drug development in oncology.

Targeted therapies are causing a dramatic change in cancer drug development. Trastuzumab, a humanized recombinant monoclonal antibody that recognizes the extracellular domain of HER2 trans-membrane protein, is among the first target-specific drugs that have been licensed for clinical use and its development represents a model of integration of new agents with classical treatment strategies. In preclinical models, trastuzumab has demonstrated a marked antiproliferative effect and a synergistic action with several chemotherapeutic agents. Monotherapy trials indicate that trastuzumab is active as a single agent in HER2 positive patients, is well tolerated, and is associated with preservation of quality of life (QoL). Furthermore, as first line therapy for metastatic breast cancer overexpressing HER2 receptor, the addition of trastuzumab to taxane-based chemotherapy significantly increased rate of objective response, time to disease progression and survival when compared with chemotherapy alone. Trastuzumab has shown important activity when used with many chemotherapeutic agents such as platinum salts, gemcitabine, vinorelbine and capecitabine and liposomal anthracyclines. Various trials are now ongoing to optimize the use of trastuzumab and to investigate its role in the adjuvant and in the neo-adjuvant setting.

Animals↗
PubMed2005

Pegylated liposomal doxorubicin in stage IVB mycosis fungoides.

BACKGROUND: Previous studies have shown that pegylated liposomal doxorubicin (LD) is effective in the treatment of relapsing or recalcitrant cutaneous T-cell lymphoma. OBJECTIVES: To evaluate the activity and toxicity of LD in patients with stage IVB mycosis fungoides (MF). METHODS: In this retrospective study, we evaluated outcomes and recorded adverse effects in 10 patients with MF (seven men and three women) with extracutaneous involvement. Patients were treated with LD 20 mg m(-2) administered intravenously every 4 weeks. RESULTS: All patients received at least two cycles of LD, three patients received four cycles and one patient received six cycles. Three patients (30%) had a partial response and two patients had stable disease. Grade 1-2 leucopenia occurred in three of the 10 patients, and grade 4 leucopenia in one. Three patients had grade 2 palmoplantar erythrodysaesthesia. CONCLUSIONS: This study demonstrates that LD is beneficial in terms of activity and toxicity in stage IVB MF. These observations should be verified in larger studies.

Aged↗
PubMed2005

Neuroendocrine differentiation after neoadjuvant hormonal treatment in prostate cancer.

AIM: Neuroendocrine (NE) differentiation occurs in various degree in the majority of prostatic adenocarcinomas and it has been correlated with tumor progression and poor prognosis. There is little knowledge about the impact of NE differentiation on tumor response to neoadjuvant hormonal treatment (NHT). The role of NE differentiation as a marker of recurrence after radical prostatectomy (RP) is also unclear. We evaluated whether there is an increase in NE differentiation during the course of NHT and whether the tumor relapse after radical surgery correlates with the extent of NE differentiation. METHODS: RP specimens from 44 patients submitted to 3 months of NHT and RP specimens from 40 nonpretreated patients were histologically assessed. Staining for NE differentiated prostate tumor cells was carried out using a specific monoclonal antibody against chromogranin A (CgA). RESULTS: CgA positive cells were found in 4 of 40 patients (10%) in the RP group and in 4 of 44 patients (9%) of the NHT+RP group. At follow-up, we had 21 biochemically relapsed patients. Among them, 6 were CgA positive (75% of 8 patients), whereas is were CgA negative (20% of 76 patients). CONCLUSIONS: The NE differentiation doesn't increase after NHT. Although not statistically significant a trend to higher risk of relapse among the chromogranin positive samples was observed. The significance of NE differentiation in the progression of the disease and its relation to other known prognostic factors remains unclear.

Antineoplastic Agents, Hormonal↗
PubMed2004

Expression of proto-oncogene c-kit in high risk prostate cancer.

AIMS: We determined whether c-kit proto-oncogene is expressed in prostate cancer and whether its expression is related with biochemical relapse in high risk localized prostate cancer patients. METHODS: c-Kit expression was evaluated by immuno-histochemistry in 94 prostate cancer samples from patients treated by radical prostatectomy followed by adjuvant hormonal therapy because all patients had a pT3a stage (initially cT2 stage). All patients presented a >7 Gleason score and a >10 pre-operative PSA value. We evaluated association between c-kit positive staining and disease free survival. RESULTS: In 26 of 94 prostate cancer, we found an epithelial positive c-kit expression. The epithelial expression was found in the peripheral zone of prostate tissue. 13/94 relapsed and, although not statistically significant (p 0.055), a trend to a higher risk of relapse among the c-kit positive samples was observed in our series of prostate cancer patients. CONCLUSIONS: Our study is only an initial experience and it is necessary to consider a higher number of patients to clarify whether c-kit is really an independent predictor for disease recurrence. Further study in this area will help to understand whether anti c-kit drugs could become an effective complement to the armamentarium of prostate cancer therapies.

Aged↗
PubMed2002

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.

Adult↗
PubMed2002

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.

Adenocarcinoma↗
PubMed2001

Survival, quality of life and breast cancer.

In recent years, evaluating quality of life (QoL) has become increasingly important as an additional measured outcome in cancer clinical trials, in particular in the field of breast cancer. This paper, after a general introduction to the present debate on the methodological issues involved in QoL evaluation, reviews results and open questions regarding the use of this measure in surgical, adjuvant and metastatic studies.

Breast Neoplasms↗
PubMed2001

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.

Angiogenesis Inhibitors↗
PubMed2001

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.

Animals↗
PubMed2000

Nuclear DNA content-derived parameters correlated with heterogeneous expression of p53 and bcl-2 proteins in clear cell renal carcinomas.

BACKGROUND: p53 and bcl-2 are two key genes involved in cell cycle and cell death regulation. Altered expression or mutation of these genes has been found in human cancers and also has been identified in clear cell renal carcinoma (RCC). Their role in RCC progression, however, is still unclear. By contrast, the prognostic significance of ploidy and S-phase fraction (SPF) have been studied extensively in RCC. To better characterize the biologic role of p53 and bcl-2 oncoproteins in RCC, we offer a multisample correlative analysis of the expression of these two proteins with ploidy and SPF. METHODS: Ploidy and SPF along with p53 and bcl-2 expression were analyzed in 296 specimens, selected by multiple sampling of 33 consecutive operable RCCs. The expression of p53 and bcl-2 proteins was studied by immunohistochemistry, and SPF and tumor ploidy were studied by flow cytometry. RESULTS: In our study, 4 of 32 (12.5%) were found to be diploid, and 28 of 32 (87.5%) cases showed an abnormal DNA content. Among the aneuploid tumors, 14 of 28 (50%) were multiploid. Heterogeneous DNA content was detected in 21 of 32 (65.6%) tumors and was correlated with the more advanced Robson stage tumor (P = 0. 03). Intratumor heterogeneity also was detected for p53 and bcl-2 protein expression. Expression of p53 protein correlated with the lack of bcl-2 protein expression (P = 0.0032), aneuploidy (P < 0. 0001), and high SPF (P = 0.0006), whereas bcl-2 expression was associated with a normal DNA content (P < 0.0001) and low SPF (P = 0. 035). CONCLUSIONS: Within each RCC, p53 and bcl-2 expression is markedly heterogeneous. Our results depicted a scenario in which bcl-2 protein, expressed by normal renal parenchyma, is still present in euploid cell clones of RCC but disappears during the progression of renal neoplasm toward a more aggressive phenotype characterized by overexpression of p53 protein, aneuploidy, and high SPF.

Adenocarcinoma, Clear Cell↗
PubMed2000

Resistance to taxanes is induced by c-erbB-2 overexpression in human MCF-10A mammary epithelial cells and is blocked by combined treatment with an antisense oligonucleotide targeting type I protein kinase A.

We have tested the sensitivity of human MCF-10A mammary epithelial cells and of their transformed derivatives overexpressing an activated c-Ha-ras gene (MCF-10A Ha-ras cells), the c-erbB-2 gene (MCF-10A c-erbB-2 cells) or both genes (MCF-10A HE cells) to different cytotoxic drugs. As compared with parental MCF-10A cells, the transformed cells exhibited an increased sensitivity to topoisomerase I- and topoisomerase II-inhibitors, and to platinum-derivatives with a 2- to 10-fold reduction in IC(50) values. A remarkable difference in sensitivity was observed following treatment with taxanes. While MCF-10A Ha-ras cells showed an increased sensitivity, MCF-10A c-erbB-2 and MCF-10A HE cells exhibited a relative resistance to taxol and taxotere, with an approximately 3.5- to 6.5-fold higher IC(50) as compared with MCF-10A cells suggesting that c-erbB-2 overexpression has a dominant effect compared with an activated c-Ha-ras gene. The type I cAMP-dependent protein kinase (PKAI) is overexpressed in cancer cells. Inhibition of PKAI by antisense oligonucleotides targeting its RIalpha regulatory subunit results in cancer cell growth inhibition. To evaluate the effect of blocking PKAI on MCF-10A cell sensitivity to taxanes, we treated these cells with taxol or taxotere in combination with a PKAI antisense oligonucleotide. Treatment with this agent, but not with a control scramble sequence, was able to overcome the effect of c-erbB-2 overexpression on MCF-10A cell sensitivity to taxol and taxotere, with a 20- to 40-fold shift in the IC(50) values for the 2 drugs.

Antineoplastic Agents↗