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F Caponigro

Publications and source records attributed to F Caponigro.

At least 19 recordsLinked to original sources
PubMed2005

Docetaxel induces p53-dependent apoptosis and synergizes with farnesyl transferase inhibitor r115777 in human epithelial cancer cells.

Docetaxel (Taxotere, DTX) is a promoter of apoptosis in cancer cells. Since cytotoxic mechanisms of DTX are not yet fully understood, we have investigated the effects of DTX on apoptosis and ras-->Erk-mediated signal transduction in human epidermoid KB, colon HT-29 and breast HCC1937 cancer cells. We have found that the exposure to 0.78 or 1.56 or 2.5 ng/ml DTX for 48 h induced apoptosis and growth inhibition in about 50 % of KB, HCC1937 and HT-29 cell population, respectively. In these experimental conditions, PARP and caspase 3 cleavage was also showed in all cell lines. KB and HCC1937 cells express a wild type p53 while HT-29 display a mutated form. Interestingly, we have found that DTX reduces the expression of mutated p53 in HT-29 and increases the expression of wild type in KB and HCC1937 cells. Moreover, DTX reduces ubiquitination of the wild type p53 in KB and HCC1937 cells and increases the ubiquitin-conjugated form of mutated p53 in HT-29 cells. Furthermore, exposure of cancer cells to DTX for 48 h increases the expression and activity of Ras and up-regulates Raf-1 and the phosphorylated isoforms of Erk-1/2. On the bases of these data, we have hypothesized that the increased activity of the ras-->erk-dependent pathway induced by DTX could be a protective signalling from the apoptosis caused by the drug. Therefore, we have used R115777, a farnesyl transferase inhibitor that inactivates ras, in combination with DTX. The combined treatment with DTX and R115777 resulted in a strong synergism in growth inhibition in the three cell lines. These data suggest the use of the combination in these therapeutic settings even if further experiments are required for the clinical translation.

Animals↗
PubMed2005

Multicentre EORTC study 16997: feasibility and phase II trial of farnesyl transferase inhibitor & gemcitabine combination in salvage treatment of advanced urothelial tract cancers.

In this study, the feasibility and activity of combined chemotherapy of the farnesyl transferase inhibitor SCH66336 and gemcitabine was evaluated. This therapy was used as second-line treatment in patients with advanced urothelial tract cancer and the influence of SCH66336 exposure on the pharmacokinetics of gemcitabine was also determined. Patients who had received one previous chemotherapy regime for advanced urothelial cancer were treated with a combination of SCH66336 (150 mg in the morning and 100 mg in the evening) and Gemcitabine (1000 mg/m2 on day 1, 8 and 15 per 28-day cycle). Dosages of gemcitabine and its metabolite dFdU were performed on day one of cycle 1 before exposure to SCH66336 and day one of cycle 2. A total of 152 cycles were administered in 33 patients (median 3, range: 1-15). No patients had severe hematological toxicity, defined as Grade 4 thrombocytopenia or febrile neutropenia. Nine partial responses and one complete response were achieved in 31 assessable patients and corresponded to an overall response rate of 32.3% [95% CI:17%-51%]. There was no influence of exposure to SCH66336 on the level of gemcitabine or dFdU in 11 assessable patients. In conclusion, a combination of SCH66336 and gemcitabine is feasible in terms of toxicity and active as second-line treatment in patients with advanced urothelial tract cancer. SCH66336 had no effect on the pharmacokinetics of gemcitabine. Randomised trials should be undertaken to clarify the role of SCH66336 in combination with gemcitabine in cancer treatment.

Adult↗
PubMed2005

Phase II study of E7070 in patients with metastatic melanoma.

E7070 is a synthetic chloro-indolyl sulphonamide that is being developed as an anti cancer agent. In this phase II study, 28 patients with metastatic melanoma received 700 mg/m(2) of E7070 as a 60-min infusion repeated every 3 weeks. Although therapy was well tolerated, with one patient receiving 14 courses of treatment, there were only minor responses on independent radiological review. E7070 does not warrant further development as a single agent for the treatment of metastatic melanoma.

Adult↗
PubMed2005

Isoprenylation of intracellular proteins as a new target for the therapy of human neoplasms: preclinical and clinical implications.

Cell proliferation, differentiation, and survival are regulated by a number of extracellular hormones, growth factors, and cytokines in complex organisms. The transduction of the signals by these factors from the outside to the nucleus often requires the presence of small intracellular proteins (i.e. ras and other small G proteins) that are linked to the plasma membrane through a isoprenyl residue that functions as hydrophobic anchor. Isoprenylation is a complex process regulated by different enzymatic steps that could represent potential molecular targets for anti-cancer strategies. In the present paper the different transduction pathways regulated by some isoprenylated proteins such as ras and other small G proteins are described. Moreover, the molecular mechanisms of the isoprenylation process and the mode of action of the different isoprenylation inhibitors are discussed with attention to statins, farnesyltransferase inhibitors (FTI) and aminobisphosphonates. The role of different candidate targets in the determination of anti-tumour effects by FTIs is also described in order to define potential molecular markers predictor of clinical response. On the basis of several preclinical data, new strategies based on multi-step enzyme inhibition or on target prioritization are proposed in order to enhance the anti-tumour activity of agents inhibiting isoprenylation. Finally, a summary of the principal data on clinical trials based on the use of FTIs and statins is given. In conclusion, the inhibition of isoprenylation is an attractive, but still not completely investigated therapeutic alternative that requires optimization for the translation in the current treatment of neoplasms.

Alkyl and Aryl Transferases↗
PubMed2005

The ErbB receptors and their ligands in cancer: an overview.

This review article provides an overview on the most recent advances on the role of ErbB receptors and growth factors of the epidermal growth factor (EGF)-family of peptides in cancer pathogenesis and progression. The ErbB tyrosine kinases and the EGF-like peptides form a complex system. In fact, the interactions occurring between receptors and ligands of these families affect the type and the duration of the intracellular signals that derive from receptor activation. Interestingly, activation of ErbB receptors is also driven by different classes of membrane receptor, suggesting that ErbB kinases can amplify growth promoting signals carried by different pathways. The importance of ErbB receptors and EGF-like peptides in development of organs and tissues has been demonstrated by using different mouse models. In vitro and in vivo studies have also shown that ErbB receptors and their ligands can act as transforming genes. However, evidence suggests that cooperation of different receptors and ligands is necessary to induce a fully transformed phenotype. Indeed, co-expression of different ErbB receptors and EGF-like growth factors is a common phenomenon in human primary carcinomas. This observation suggests that the growth and the survival of carcinoma cells is sustained by a network of receptors/ligands of the ErbB family. In this respect, the contemporary expression of different ErbB tyrosine kinases and/or EGF-like growth factors in human carcinomas might also affect tumor response to target based agents directed against the ErbB receptor/ligand system.

Animals↗
PubMed2003

Phase II study of XR 5000 (DACA), an inhibitor of topoisomerase I and II, administered as a 120-h infusion in patients with non-small cell lung cancer.

XR5000 is a tricyclic carboxamide-based cytotoxic agent that binds to DNA by intercalation and stimulates DNA cleavage by inhibition of both topoisomerase I and II. The aim of this study was to evaluate the antitumoral activity and safety profile of XR5000 given as second-line chemotherapy in patients with advanced non-small cell lung cancer (NSCLC). Patients received XR5000 at the dose of 3010 mg/m(2) as a 120-h central venous infusion every 3 weeks. The 15 patients (median age 56 years, range 48-71 years) enrolled had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 (3 patients), 1 (11 patients) or 2 (1 patient). A total of 32 cycles of XR5000 (median 2, range 1-6) were given to 14 patients. No objective response (assessed according to World Health Organization (WHO) criteria) was documented in the 12 evaluable patients by an external review panel; in 4 out of the 12 patients disease stabilisation was recorded. The following toxicities graded according to the Common Toxicity Criteria (CTC) version 2.0. were observed: one grade 3 and two grade 4 granulocytopenia, one grade 3 and one grade 4 thrombocytopenia, one grade 3 deep venous thrombosis, one grade 3 fatigue, and grade 3 undocumented epileptic seizures which led to death in 2 patients. With only 4 out of 12 patients reaching stable disease when using this dose and regimen, further evaluation of XR5000 in advanced NSCLC is not justified.

Acridines↗
PubMed2003

Results of randomised phase II studies comparing S16020 with methotrexate in patients with recurrent head and neck cancer.

BACKGROUND: The purpose of this study was to carry out two randomised phase II trials of S16020, a new olivacine derivative, tested as a single agent in patients with recurrent head and neck cancer, using methotrexate as the control arm to validate the results. PATIENTS AND METHODS: S16020 at either 80 or 100 mg/m2 was administered as a 3-h infusion every 3 weeks. Methotrexate, 40 or 50 mg/m2, was given by bolus injection, weekly for a minimum of 6 weeks. In total, 36 patients were entered in the randomised studies (25 in an initial study, 11 in a confirmatory study) of whom 24 received S16020 and 12 received methotrexate. RESULTS: A scheduled interim analysis showed one patient having a non-confirmed objective response with S16020 and three patients having a confirmed objective response with methotrexate. In the methotrexate group, there were no patients with severe non-haematological toxicity. With S16020, there was a high incidence of severe non-haematological toxicities, including asthenia, oedema of the face, oedema and pain at the tumour sites and erythematous rash; consequently, both studies were stopped. CONCLUSIONS: Both studies were stopped due to the poor anticipated benefit/risk ratio for S16020, although time to progression and overall survival time were similar in both treatment arms.

Adult↗
PubMed2002

Phase II study of XR 5000, an inhibitor of topoisomerases I and II, in advanced colorectal cancer.

XR 5000 is one of a series of tricyclic carboxamide-based cytotoxic agents. It binds to DNA by intercalation and stimulates DNA cleavage by inhibition of both topoisomerase I and II, thus possibly overcoming the resistance resulting from downregulation of either enzyme. Twenty patients with advanced or metastatic colorectal cancer, unpretreated for metastatic disease, received XR 5000 at the dose of 3010 mg/m(2) in a 120-h central intravenous (i.v.) infusion every 3 weeks. Response was evaluated every two cycles. No complete (CR) or partial responses (PR) were observed in eligible patients (response rate, 0 of 19, 0%; 95% confidence interval (CI): 0-18%). 5 patients had stable disease, which lasted from 79 to 157 days. Haematological toxicity was low, since only one grade 4 neutropenia and two grade 3 anaemia were observed. Other treatment-related grade 3-4 toxicities were: deep venous thrombosis (2 cases), liver toxicity, diarrhoea, anorexia, dyspnoea, chest pain, infection (1 case each). Despite the good toxicity profile, these results do not support further trials with XR 5000 in metastatic colorectal cancer.

Acridines↗
PubMed2002

Patient preference and pharmacokinetics of oral modulated UFT versus intravenous fluorouracil and leucovorin: a randomised crossover trial in advanced colorectal cancer.

The aim of this study was to determine the patient's preference for oral UFT/leucovorin (LV) or intravenous (i.v.) 5-fluorouracil (5-FU)/LV chemotherapy in metastatic colorectal cancer and to compare 5-FU exposure with these two treatment options. A total of 37 previously untreated patients with advanced colorectal cancer were randomised to start treatment with either oral UFT 300 mg/m2/day plus oral LV 90 mg/day for 28 days every 5 weeks or i.v. 5-FU 425 mg/m2/day plus LV 20 mg/m2/day for 5 days every 4 weeks. For the second treatment cycle, patients were crossed-over to the alternative treatment regimen. Prior to the first and after the second therapy cycle, patients were required to complete a therapy preference questionnaire (TPQ). The pharmacokinetics of 5-FU were determined by taking blood samples on days 8, 15 or 22 and 28 for UFT and on days 1 and 5 for i.v. 5-FU. 36 patients were eligible. 84% of the patients preferred oral UFT over i.v. 5-FU. After having experienced both treatment modalities, patients indicated taking the medication at home, less stomatitis and diarrhoea, and pill over injection as the most important reasons for their preference. The area under the plasma concentration curve (AUC) for 5-FU after UFT administration was 113 microM x min on day 8, 114 on day 15 and 98 on day 28; the peak levels (Cmax) were 1.2, 1.3 and 1.0 microM, respectively. The AUC for the 5-FU/LV courses was 3083 microM x min for day 1 and 3809 for day 5 (P=0.002). The Cmax was 170.1 and 196.2 microM (P=0.06) and the clearance 2.6 and 1.9 l/min, respectively (P=0.002). Patients with metastatic colorectal cancer clearly preferred oral over i.v. chemotherapy treatment. This choice was most importantly influenced by convenience and toxicity considerations. Although i.v. bolus 5-FU leads to higher peak 5-FU concentrations and AUC values compared with oral UFT, this pharmacokinetic advantage of i.v. 5-FU seems to translate mainly into higher toxicity as seen in large randomised studies comparing oral UFT/LV with i.v. 5-FU/LV. Oral UFT/LV compares favourably with i.v. 5-FU/LV in terms of toxicity and patient's preference and leads to prolonged 5-FU exposure, which is comparable to continuous i.v. 5-FU treatment.

Adenocarcinoma↗
PubMed2001

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.

Administration, Oral↗
PubMed2001

Phase I study of mitoxantrone, raltitrexed, levofolinic acid and 5-fluorouracil in advanced solid tumours.

PURPOSE: We have recently evaluated the combination of raltitrexed, levofolinic acid (LFA) and 5-fluorouracil (5-FU) in advanced head and neck and colorectal cancer, and we have shown that this combination is well tolerated and has clinical activity. Clinical combination studies have shown that raltitrexed and anthracyclines can be combined at full doses without unexpected toxicities. Based on these observations, we started a phase I study of mitoxantrone plus raltitrexed administered on day 1, followed by LFA and 5-FU on day 2 in patients with advanced solid tumors. PATIENTS AND METHODS: Mitoxantrone was given at a starting dose of 6 mg/m2, raltitrexed at a fixed dose of 3 mg/m2, LFA at a fixed dose of 250 mg/m2, and 5-FU at a starting dose of 750 mg/m2. Mitoxantrone and 5-FU doses were subsequently escalated alternately up to dose-limiting toxicity. Treatment was repeated every 14 days. RESULTS: Four dose levels were tested in 18 patients. All three patients treated at the fourth dose level had grade 4 neutropenia after the first cycle. Therefore, this level was defined as the maximum tolerated dose and the dose level immediately below (mitoxantrone 7 mg/m2 and 5-FU 900 mg/m2) was selected for further evaluation. Neutropenia was the main toxic effect. Nonhaematologic side effects were mild. One complete response and five partial responses (all but one in patients with head and neck cancer) were observed, for an overall response rate of 33% (95% confidence interval, 13% to 59%). CONCLUSIONS: Mitoxantrone, raltitrexed and 5-FU can be combined at doses which are close to those used in monotherapy. The observed activity is encouraging, especially in the subset of patients with head and neck cancer.

Adult↗
PubMed2001

Docetaxel and cisplatin in locally advanced or metastatic squamous-cell carcinoma of the head and neck: a phase II study of the Southern Italy Cooperative Oncology Group (SICOG).

BACKGROUND: Docetaxel is one of the most promising new drugs against squamous-cell carcinoma of the head and neck (SCCHN), while cisplatin is one of the most active single agents. A phase I study has shown the feasibility of the combination of the two drugs, and activity in SCCHN has been seen. PATIENTS AND METHODS: Patients with locally advanced, inoperable, or metastatic SCCHN, never pretreated with radiotherapy or chemotherapy, received three courses of docetaxel 75 mg/m2 and cisplatin 100 mg/m2, every three weeks. Thereafter, responsive metastatic patients received additional chemotherapy, while patients with locally advanced disease underwent radiation therapy. RESULTS: Forty-six patients (forty-five with locally advanced, one with metastatic disease) were entered into the study. Ten patients did not complete three courses of chemotherapy because of early death; one patient discontinued treatment after one course. Twenty-one objective responses were observed (46%, 95% confidence interval (CI): 31%-60%), including five complete responses (11%) and sixteen partial responses (35%). Following induction chemotherapy plus radiation therapy, 9 of 21 evaluable patients were rendered disease free, while 8 additional patients had a partial response. After a median follow-up of 18 months, the median duration of response was 12 months, (range 3-25+), and the median overall survival was 11 months. Six early deaths were considered possibly treatment-related (sepsis following grade 4 neutropenia in two cases, hypovolemic shock following severe diarrhea in four cases). Neutropenia was the most severe toxicity (grade 3-4 in 28 patients, median duration 4 days); diarrhea and vomiting were the most troublesome non-haematologic toxicities (grade 4 in 4 and 3 patients, respectively). CONCLUSIONS: The combination of docetaxel and cisplatin is active in SCCHN, but toxicity is substantial. This schedule does not appear to offer any advantage compared with conventional regimens.

Adult↗
PubMed2001

Raltitrexed/5-fluorouracil-based combination chemotherapy regimens in anticancer therapy.

Preclinical evidence of a schedule-dependent synergism between raltitrexed and 5-fluorouracil (5-FU) has prompted clinical studies of this combination. We review the main preclinical and clinical results of raltitrexed/5-FU-based combination chemotherapy regimens in anticancer therapy. Promising results include: response rates of 25 and 23% with combinations of raltitrexed/5-FU/levofolinic acid (LFA) as first-line treatment and oxaliplatin/raltitrexed/5-FU/LFA as second-line treatment of metastatic colorectal cancer, respectively; and a 67% response rate in a phase I study of cisplatin/raltitrexed/5-FU/LFA as first-line treatment of advanced head and neck cancer, including a 100% response rate at the recommended dose. These combinations were well tolerated, with neutropenia as the main dose-limiting toxicity, allowing the drugs to be combined at the doses used in monotherapy. These results suggest a role for raltitrexed within combination regimens in colorectal cancer therapy, as well as other tumors such as head and neck cancer. A further potential application of raltitrexed in combination therapies is within multidisciplinary chemo-radiotherapy strategies, mainly in rectal cancer. Phase II studies are planned/ongoing to investigate these interesting possibilities.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Phase I study of Caelyx (doxorubicin HCL, pegylated liposomal) in recurrent or metastatic head and neck cancer.

BACKGROUND: Pegylated liposome technology represents a favourable drug-carrier system, since stealth liposomal drugs have a reduced clearance with prolonged circulation half-life and selective drug accumulation in tissues with increased vascular permeability, such as tumor tissues. Caelyx is a pegylated liposome containing doxorubicin, which has been developed to target drug delivery to cancer cells, thus reducing toxicities. Biodistribution studies have shown a selective tumor uptake in patients with advanced head and neck cancer (HNC), thus justifying the present phase I study. PATIENTS AND METHODS: Patients with recurrent or metastatic HNC were treated with Caelyx administered at the starting dose of 30 mg/m2 every three weeks and escalated by 5 mg/m2 per step. Dose escalation was stopped if more than a third of patients of a given cohort had dose-limiting toxicity (DLT), which was defined as grade 4 neutropenia or thrombocytopenia, grade 3 febrile neutropenia, grade 3 thrombocytopenia with bleeding, grade 3 non-hematologic toxicity (except for nausea and alopecia), or > 2 week delay in chemotherapy recycling. The above dose level was defined as maximum tolerated dose (MTD) and the dose level immediately below was recommended for phase II evaluation. Response was evaluated after three courses of chemotherapy. RESULTS: Twenty-four patients were treated at five dose levels. At 50 mg/m2, three out of six patients had grade 3 stomatitis; therefore, this level was defined as MTD and 45 mg/m2 was the selected dose for phase II. Stomatitis occurred in 11 patients across all dose levels, considering all delivered cycles. Neutropenia occurred in 10 of 24 patients, but reached grade 4 in only 2 patients at fourth dose level. Skin toxicity, mainly appearing in the form of palmar-plantar erythrodysestesia, was the most frequent toxicity, occurring in 14 patients. Other side effects were mild. One complete response (4%) and seven partial responses (29%) were observed, for an overall response rate of 33% (95% confidence interval (95% CI): 16%-55%). CONCLUSIONS: Caelyx is a safe and promising new treatment in HNC, that deserves further evaluation both alone and integrated within chemo-radiotherapy strategies.

Adult↗
PubMed2000

Cisplatin, raltitrexed, levofolinic acid and 5-fluorouracil in locally advanced or metastatic squamous cell carcinoma of the head and neck: a phase I-II trial of the Southern Italy Cooperative Oncology Group (SICOG).

BACKGROUND: The combination of cisplatin (CDDP) and 5-fluorouracil (5-FU) can be regarded as a reference regimen in squamous cell carcinoma of the head and neck (SCCHN). Raltitrexed (Tomudex) is a direct and specific thymidilate synthase (TS) inhibitor, which has shown clinical activity against SCCHN in a previous phase I study, when combined with 5-FU and levo-folinic acid (LFA). Preclinical data support the combination of CDDP and raltitrexed. The aim of the present study was to evaluate the combination of cisplatin, raltitrexed. LFA and 5-FU in a phase I-II study. PATIENTS AND METHODS: Patients with locally advanced or metastatic SCCHN were treated with a combination of cisplatin at the starting dose of 40 mg/m2. followed by raltitrexed at the starting dose of 2.5 mg/m2 on day 1; levo-folinic acid at fixed dose of 250 mg/m2, followed by 5-fluorouracil at the starting dose of 750 mg/m2 on day 2. Doses of the three cytotoxic agents were alternately escalated up to dose-limiting toxicity (DLT). Treatment was recycled every two weeks and given up to a maximum of eight courses; after chemotherapy, patients with locally advanced disease received a locoregional treatment. RESULTS: Forty-five patients were entered into the study. Six dose levels were tested. At CDDP 50 mg/m2, raltitrexed 3 mg/m2, 5-FU 900 mg/m2, four out of six patients showed DLT, which was in all cases grade 4 neutropenia. Therefore, this dose level was defined as maximum tolerated dose (MTD). CDDP 60 mg/m2, raltitrexed 2.5 mg/m2, LFA 250 mg/m2, 5-FU 900 mg/m2 was the dose level recommended for phase II. CDDP, Raltitrexed and 5-FU mean actually delivered dose intensities at the selected dose level were 26, 1.05, and 378 mg/m2/week, respectively. Neutropenia was the main side effect and was observed even at the lowest dose levels. Nonhematologic side effects were mild. Nine complete responses (20%) and twenty-one partial responses (47%) were observed, for an overall response rate of 67% (95% confidence interval (95% CI): 51%-80%), according to intention to treat analysis. Fifteen of fifteen patients (100%) treated at the dose level selected for phase II had an objective response (5 complete responses, 10 partial responses). CONCLUSIONS: The results of our dose escalation clearly demonstrate that it is possible to combine CDDP, raltitrexed, and modulated 5-FU at effective doses, without unexpected toxicities. The response data point to an impressive clinical activity, which will be better defined by an ongoing large phase II study.

Adult↗
PubMed1999

The protein kinase C inhibitor CGP41251 suppresses cytokine release and extracellular signal-regulated kinase 2 expression in cancer patients.

Components of cell signaling pathways provide important targets for anticancer drugs. Protein kinase C (PKC) is a serine/threonine-specific kinase that regulates cell growth and differentiation. It is also implicated in tumor promotion. The staurosporine analogue CGP41251 is a PKC inhibitor, and it is currently in a Phase I clinical trial for treatment of advanced cancer. However, it is difficult to define its biological activity. We have used two approaches to measure the in vivo biological response to CGP41251: (a) sequential whole blood samples were taken from 27 patients before and during treatment and incubated with mitogen (PHA), and cytokine [tumor necrosis factor (TNF)-alpha and interleukin (IL)-6] release was measured ex vivo; and (b) peripheral blood lymphocytes were isolated from seven of these patients, and the levels of extracellular signal-regulated kinase 2 were measured by Western blotting. Response to PHA was significantly lowered during treatment (P < 0.001 for TNF-alpha production; P < 0.03 for IL-6). This was most evident at 7 and 28 days after the start of treatment in patients receiving higher doses (150-300 mg/day; P = 0.002 and P = 0.02, respectively, for TNF-alpha and P = 0.001 and P = 0.003, respectively, for IL-6 release). Whole blood cytokine production returned to pretreatment levels after drug administration ceased. The levels of extracellular signal-regulated kinase 2 were reduced by 50-97% during treatment in all seven patients tested. These results show for the first time that a PKC inhibitor can block in vivo signaling pathways in cancer patients. The assays we describe complement toxicity studies in selecting relevant doses for Phase II trial of novel agents, particularly when biological activity occurs at doses below those that cause obvious side effects.

Adult↗