Antitumor Efficacy (antitumor + efficacy)

Distribution by Scientific Domains


Selected Abstracts


Prospective non-randomized study of preoperative concurrent platinum plus 5-fluorouracil-based chemoradiotherapy with or without paclitaxel in esophageal cancer patients: long-term follow-up

DISEASES OF THE ESOPHAGUS, Issue 2 2010
M. Zemanova
SUMMARY Combined modality treatment for esophageal carcinoma seems to improve survival over surgery alone. Different combinations of cytotoxic drugs have been studied to improve antitumor efficacy and limit the toxicity of chemoradiotherapy (CRT) with inconsistent results. We present a prospective study of neoadjuvant CRT with or without paclitaxel in chemotherapy schedule. One hundred seven patients (93 males, 14 females), median age 59 years (range 44,76), with operable esophageal cancer were enrolled. They received the following neoadjuvant therapy: Carboplatin, area under curve (AUC) = 6, intravenously on days 1 and 22, 5-fluorouracil (5-FU), 200 mg/m2/day, continuous infusion on days 1 to 42, radiation therapy 45 grays/25fractions/5 weeks beginning on day 1. Forty-four patients (41%) were furthermore non-randomly assigned to paclitaxel 200 mg/m2/3 h intravenously on days 1 and 22. Nutritional support from the beginning of the treatment was offered to all patients. Surgery was done within 4,8 weeks after completion of CRT, if feasible. All patients were evaluated for grade 3 plus 4 toxicities: leukopenia (28%), neutropenia (30%), anemia (6%), thrombocytopenia (31%), febrile neutropenia (6%), esophagitis (24%), nausea and vomiting (7%), pneumotoxicity (8%). Seventy-eight patients (73%) had surgery and 63 of them were completely resected. Twenty-two patients (20%) achieved pathological complete remission, and additional 20 (19%) had node-negative and esophageal wall-positive residual disease. There were 10 surgery-related deaths, mostly due to pulmonary insufficiency. Twenty-nine patients were not resected, 15 for early progression, 14 for medical reasons or patient refusal. After a median follow-up of 52 months (range 27,80), median survival of 18.0 months and 1-, 2-, 3- and 5-year survival of 56.7, 37.5, 27.0 and 21% was observed in the whole group of 107 patients. Addition of paclitaxel to carboplatin and continual infusion of FU significantly increased hematologic and non-hematologic toxicity, but treatment results as overall survival or time to progression did not differ significantly in groups with and without paclitaxel. Patients achieving pathological complete remission or nodes negativity after neoadjuvant therapy had favorable survival prognosis, whereas long-term prognosis of node positive patients was poor. Distant metastases prevailed as a cause of the treatment failure. Factors significant for survival prognosis in multivariate analysis were postoperative node negativity, performance status, and grade of dysphagia. Addition of paclitaxel to carboplatin and continual FU significantly increased hematologic and non-hematologic toxicity without influencing efficacy of the treatment. This study confirmed improved prognosis of patients after achieving negativity of nodes. Distant metastases prevailed as cause of the treatment failure. Prospectively, it is important to look for a therapeutic combination with better systemic effect. [source]


The dual EGFR/HER-2 tyrosine kinase inhibitor lapatinib sensitizes colon and gastric cancer cells to the irinotecan active metabolite SN-38

INTERNATIONAL JOURNAL OF CANCER, Issue 12 2009
Melissa J. LaBonte
Abstract Members of the human epidermal receptor (HER) family are frequently associated with aggressive disease and poor prognosis in multiple malignancies. Lapatinib is a dual tyrosine kinase inhibitor targeting the epidermal growth factor receptor (EGFR) and HER-2. This study evaluated the therapeutic potential of lapatinib, alone and in combination with SN-38, the active metabolite of irinotecan (CPT-11), in colon and gastric cancer cell lines. Concentration-dependent antiproliferative effects of both lapatinib and SN-38 were observed in all colon and gastric cancer cell lines tested but varied significantly between individual cell lines (lapatinib range 0.08,11.7 ,M; SN-38 range 3.6,256 nM). Lapatinib potently inhibited the growth of a HER-2 overexpressing gastric cancer cell line and demonstrated moderate activity in gastric and colon cancer cells with detectable HER-2 expression. The combination of lapatinib and SN-38 interacted synergistically to inhibit cell proliferation in all colon and gastric cancer cell lines tested. Cotreatment with lapatinib and SN-38 also resulted in enhanced cell cycle arrest and the induction of apoptosis with subsequent cellular pharmacokinetic analysis demonstrating that lapatinib promoted the increased intracellular accumulation and retention of SN-38 when compared to SN-38 treatment alone. Finally, the combination of lapatinib and CPT-11 demonstrated synergistic antitumor efficacy in the LoVo colon cancer mouse xenograft model with no apparent increase in toxicity compared to CPT-11 monotherapy. These results provide compelling preclinical rationale indicating lapatinib to be a potentially efficacious chemotherapeutic combination partner for irinotecan in the treatment of gastrointestinal carcinomas. © 2009 UICC [source]


Pharmacokinetics, biodistribution, and antitumor efficacy of a human glandular kallikrein 2 (hK2)-activated thapsigargin prodrug

THE PROSTATE, Issue 4 2006
Samuel Janssen
Abstract BACKGROUND Prostate cancer cells secrete unique proteases such as prostate-specific antigen (PSA) and human glandular kallikrein 2 (hK2) that represent targets for the activation of prodrugs as systemic treatment of metastatic prostate cancer. Previously, a combinatorial peptide library was screened to identify a highly active peptide substrate for hK2. The peptide was coupled to an analog of the potent cytotoxin thapsigargin, L12ADT, to generate an hK2-activated prodrug that was efficiently hydrolyzed by purified hK2, stable to hydrolysis in human and mouse plasma in vitro and selectively toxic to hK2 producing prostate cancer cells in vitro. METHODS In the current study, toxicology, pharmacokinetics, prodrug biodistribution, and antitumor efficacy studies were performed to evaluate the hK2-activated prodrug in vivo. RESULTS The single intravenous maximally tolerated dose of prodrug was 6 mg/kg (i.e., 3.67 µmole/kg) which produced peak serum concentration of ,36 µM and had a half-life of ,40 min. In addition, over a 24 hr period <0.5% of free L12ADT analog was observed in plasma. The prodrug demonstrated significant antitumor effect in vivo while it was being administered, but prolonged intravenous administration was not possible due to local toxicity to tail veins. Subcutaneous administration of equimolar doses produced lower plasma AUC compared to intravenous dosing but equivalent intratumoral levels of prodrug following multiple doses. CONCLUSIONS The hK2-activated prodrug was stable in vivo. The prodrug, however, was rapidly cleared and difficult to administer over prolonged dosing interval. Additional studies are underway to assess antitumor efficacy with prolonged administration of higher subcutaneous doses of prodrug. Second-generation hK2-activated thapsigargin prodrugs with increased half-lives and improved formulations are also under development. © 2005 Wiley-Liss, Inc. [source]


A phase I/II study of weekly high-dose erlotinib in previously treated patients with nonsmall cell lung cancer,

CANCER, Issue 5 2006
Daniel T. Milton MD
Abstract BACKGROUND. Preclinical studies have suggested that erlotinib at high doses may inhibit additional sites downstream of the epidermal growth factor receptor (EGFR), resulting in greater antitumor efficacy. The objective of this study was to determine the tolerability and efficacy of high-dose erlotinib administered on a weekly schedule to patients with advanced nonsmall cell lung cancer (NSCLC). METHODS. The authors conducted a Phase I/II trial of weekly erlotinib in patients with progressive NSCLC who had received previous chemotherapy. In the Phase I portion, patients were enrolled in 3-patient cohorts at erlotinib dose levels of 1200 mg, 1600 mg, and 2000 mg once weekly. The Phase II portion was designed to determine the major objective response rate of the dose identified in the Phase I portion of the trial. RESULTS. Twenty-seven patients were enrolled. No dose-limiting toxicity was observed. Grade 1 and 2 rash and diarrhea were the principle toxicities, and each occurred in 92% of patients. Among 21 patients who were treated at the Phase II dose of 2000 mg weekly, a single objective response was identified, yielding a response rate of 5% (95% confidence interval, 0.2,22%). For this cohort, the median survival was 9.5 months. The sole radiographic response occurred in a patient whose pretreatment tumor specimen harbored an EGFR exon 19 deletion. CONCLUSIONS. Erlotinib at a dose of 2000 mg administered weekly was tolerated well by these patients with advanced NSCLC. The 5% objective response rate did not reach the stated objective at the interim efficacy analysis, prompting the closure of the study. Cancer 2006. © 2006 American Cancer Society. [source]


Receptor activator of NF-,B ligand, macrophage inflammatory protein-1,, and the proteasome

CANCER, Issue S3 2003
Novel therapeutic targets in myeloma
Abstract BACKGROUND The bone destruction in myeloma patients is largely responsible for the clinical features of the disease. However, only recently has attention focused on identifying and developing drugs targeted specifically at the osteolysis. Receptor activator of NF-,B ligand (RANKL), macrophage inflammatory protein (MIP)-1,, and proteasomal function have been implicated in the pathogenesis of myeloma and associated bone disease. We provide "proof of principle" in preclinical myeloma models that these are indeed valid molecular targets in development of novel therapeutics. METHODS The efficacy of antagonists of RANKL and MIP-1, bioactivities (RANK.Fc and neutralizing monoclonal anti-MIP-1, antibody) in ameliorating osteolysis and reducing tumor burden was evaluated in a mouse model in which murine myeloma 5TGM1 cells are injected intravenously into syngeneic mice. In addition, the activity of a petidyl aldehyde proteasome inhibitor (proteasome inhibitor-1 [PSI]) on tumor growth was tested in a murine 5TGM1 plasmacytoma model and in mice intravenously inoculated with 5TGM1 cells. RESULTS RANK.Fc and anti-MIP-1, antibody inhibited the development and progression of osteolytic lesions and significantly reduced tumor load assessed by serum monoclonal paraprotein titers. Intratumoral injections of PSI inhibited growth of 5TGM1 plasmacytomas and induced tumor regression in some cases. In addition, systemic administration of PSI significantly prolonged time to onset of paraplegia in tumor-bearing mice. CONCLUSIONS The results highlight the critical roles of RANKL and MIP-1, in the development and progression of myeloma and provide a basis for future evaluation in myeloma patients of novel therapeutics that disrupt interactions of RANKL and MIP-1, with their cognate receptors. The data also suggest that further studies in preclincal myeloma models aimed at identifying other proteasome inhibitors with antitumor efficacy would be worthwhile. Cancer 2003;97(3 Suppl):813,7. © 2003 American Cancer Society. DOI 10.1002/cncr.11133 [source]


Enhanced antitumor efficacy of folate-linked liposomal doxorubicin with TGF-, type I receptor inhibitor

CANCER SCIENCE, Issue 10 2010
Yukimi Taniguchi
Tumor cell targeting of drug carriers is a promising strategy and uses the attachment of various ligands to enhance the therapeutic potential of chemotherapy agents. Folic acid is a high-affinity ligand for folate receptor, which is a functional tumor-specific receptor. The transforming growth factor (TGF)-, type I receptor (T,R-I) inhibitor A-83-01 was expected to enhance the accumulation of nanocarriers in tumors by changing the microvascular environment. To enhance the therapeutic effect of folate-linked liposomal doxorubicin (F-SL), we co-administrated F-SL with A-83-01. Intraperitoneally injected A-83-01-induced alterations in the cancer-associated neovasculature were examined by magnetic resonance imaging (MRI) and histological analysis. The targeting efficacy of single intravenous injections of F-SL combined with A-83-01 was evaluated by measurement of the biodistribution and the antitumor effect in mice bearing murine lung carcinoma M109. A-83-01 temporarily changed the tumor vasculature around 3 h post injection. A-83-01 induced 1.7-fold higher drug accumulation of F-SL in the tumor than liposome alone at 24 h post injection. Moreover F-SL co-administrated with A-83-01 showed significantly greater antitumor activity than F-SL alone. This study shows that co-administration of T,R-I inhibitor will open a new strategy for the use of FR-targeting nanocarriers for cancer treatment. (Cancer Sci 2010); 00: 000,000 [source]


Dofequidar fumarate sensitizes cancer stem-like side population cells to chemotherapeutic drugs by inhibiting ABCG2/BCRP-mediated drug export

CANCER SCIENCE, Issue 11 2009
Ryohei Katayama
The ATP-binding cassette (ABC) transporters (ABC-T) actively efflux structurally and mechanistically unrelated anticancer drugs from cells. As a consequence, they can confer multidrug resistance (MDR) to cancer cells. ABC-T are also reported to be phenotypic markers and functional regulators of cancer stem/initiating cells (CSC) and believed to be associated with tumor initiation, progression, and relapse. Dofequidar fumarate, an orally active quinoline compound, has been reported to overcome MDR by inhibiting ABCB1/P-gp, ABCC1/MDR-associated protein 1, or both. Phase III clinical trials suggested that dofequidar had efficacy in patients who had not received prior therapy. Here we show that dofequidar inhibits the efflux of chemotherapeutic drugs and increases the sensitivity to anticancer drugs in CSC-like side population (SP) cells isolated from various cancer cell lines. Dofequidar treatment greatly reduced the cell number in the SP fraction. Estimation of ABC-T expression revealed that ABCG2/breast cancer resistance protein (BCRP) mRNA level, but not the ABCB1/P-gp or ABCC1/MDR-associated protein 1 mRNA level, in all the tested SP cells was higher than that in non-SP cells. The in vitro vesicle transporter assay clarified that dofequidar had the ability to suppress ABCG2/BCRP function. Dofequidar treatment sensitized SP cells to anticancer agents in vitro. We compared the antitumor efficacy of irinotecan (CPT-11) alone with that of CPT-11 plus dofequidar in xenografted SP cells. Although xenografted SP tumors showed resistance to CPT-11, treatment with CPT-11 plus dofequidar greatly reduced the SP-derived tumor growth in vivo. Our results suggest the possibility of selective eradication of CSC by inhibiting ABCG2/BCRP. (Cancer Sci 2009) [source]


Therapeutic antitumor efficacy of monoclonal antibody against Claudin-4 for pancreatic and ovarian cancers

CANCER SCIENCE, Issue 9 2009
Masayo Suzuki
Claudin-4 (CLDN4) is a tetraspanin transmembrane protein of tight junction structure and is highly expressed in pancreatic and ovarian cancers. In this study, we aimed to generate an anti-Claudin-4 monoclonal antibody (mAb) and evaluate its antitumor efficacy in vitro and in vivo. To isolate specific mAb, we generated CLDN3, 4, 5, 6, and 9, expressing Chinese hamster ovary (CHO) cells, and then used them as positive and negative targets through cell-based screening. As a result, we succeeded in isolating KM3900 (IgG2a), which specifically bound to CLDN4, from BXSB mice immunized with pancreatic cancer cells. Immunoprecipitation and flow cytometry analysis revealed that KM3900 recognized the conformational structure and bound to extracellular loop 2 of CLDN4. Furthermore, binding of KM3900 was detected on CLDN4-expressing pancreatic and ovarian cancer cells, but not on negative cells. Next, we made the mouse,human chimeric IgG1 (KM3934) and evaluated its antitumor efficacy. KM3934 induced dose-dependent antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in vitro, and significantly inhibited tumor growth in MCAS or CFPAC-1 xenograft SCID mice in vivo (P < 0.05). These results suggest that mAb therapy against CLDN4 is promising for pancreatic and ovarian cancers. (Cancer Sci 2009; 100: 1623,1630) [source]


Acyl-CoA synthetase as a cancer survival factor: its inhibition enhances the efficacy of etoposide

CANCER SCIENCE, Issue 8 2009
Tetsuo Mashima
Lipid metabolism is often elevated in cancer cells and plays an important role in their growth and malignancy. Acyl-CoA synthetase (ACS), which converts long-chain fatty acids to acyl-CoA, is overexpressed in various types of cancer. However, the role of ACS in cancer remains unknown. Here, we found that ACS enzyme activity is required for cancer cell survival. Namely, the ACS inhibitor Triacsin c induced massive apoptosis in glioma cells while this cell death was completely suppressed by overexpression of ACSL5, the Triacsin c,resistant ACS isozyme, but not by overexpression of a catalytically inactive ACSL5 mutant. ACS inhibition by Triacsin c markedly potentiated the Bax-induced intrinsic apoptotic pathway by promoting cytochrome c release and subsequent caspase activation. These effects were abrogated by ACSL5 overexpression. Correspondingly, ACS inhibition synergistically potentiated the glioma cell death induced by etoposide, a well-known activator of apoptosis. Furthermore, in a nude mouse xenograft model, Triacsin c at a non-toxic dose enhanced the antitumor efficacy of a low-dose chemotherapy with etoposide. These results indicate that ACS is an apoptosis suppressor and that ACS inhibition could be a rational strategy to amplify the antitumor effect of etoposide. (Cancer Sci 2009) [source]


Optimal amount of monocyte chemoattractant protein-1 enhances antitumor effects of suicide gene therapy against hepatocellular carcinoma by M1 macrophage activation

CANCER SCIENCE, Issue 10 2008
Tomoya Tsuchiyama
Suicide gene therapy combined with chemokines provides significant antitumor efficacy. Coexpression of suicide gene and monocyte chemoattractant protein-1 (MCP-1) increases antitumor effects in murine models of hepatocellular carcinoma (HCC) and colon cancer. However, it is unclear whether the doses administered achieved the maximum antitumor effects. We evaluated antitumor effects of various amounts of recombinant adenovirus vector (rAd) expressing MCP-1 in the presence of a suicide gene in a murine model of HCC. HCC cells were transplanted subcutaneously into BALB/c nude mice, and transduced with a fixed amount of Ad-tk harboring the suicide gene, HSV-tk, and various doses of Ad-MCP1 harboring MCP-1 (ratios of 1:1, 0.1:1, and 0.01:1 relative to Ad-tk). Growth of primary tumors was suppressed when treated with Ad-tk plus Ad-MCP1 (1:1 and 1:0.1) as compared with Ad-tk alone. The antitumor effects against tumor rechallenge tended to be high in the Ad-tk plus Ad-MCP1 group (1:0.1). The effects were dependent on production of Th1 type-cytokines. Delivery of an optimal amount of rAd expressing MCP-1 enhanced the antitumor effects of suicide gene therapy against HCC by M1 macrophage activation, suggesting that this is a plausible form of cancer gene therapy to prevent HCC progression and recurrence. (Cancer Sci 2008; 99: 2075,2082) [source]


Potent antitumor effect elicited by superantigen-linked tumor cells transduced with heat shock protein 70 gene

CANCER SCIENCE, Issue 2 2004
Changxin Huang
Heat shock proteins (HSP) induce antitumor-specific immunity via a unique mechanism, but HSP alone fails to produce a satisfactory antitumor efficacy. We considered that the potent immune-activation of superantigen (SAg) might assist HSP to elicit a strong tumor-antigen-specific immunity. We initially prepared B16 melanoma cells linked to SAg SEA via a fusion protein with a trans-membrane sequence (TM), and demonstrated that SEA thus anchored on the tumor cell surface could elicit strong antitumor immunity. We then prepared cells transduced with an inducible heat shock protein 70 (HSP70) gene, and bearing SEA-TM fusion protein on the cell surface, and used these cells as a dual-modified vaccine. In this study, either in a therapeutic setting or in a pre-immune model, the SEA-anchored vaccine or the HSP70 gene-modified vaccine induced marked tumor suppression, prolonged survival, augmented lymphocyte proliferation and higher NK and CTL activity in C57BL/6 mice compared with their controls (P<0.01), though they were less effective than the dual-modified vaccine. Among these vaccines, the dual-modified vaccine showed the best therapeutic efficacy in B16 melanoma-bearing mice and gave the greatest protection against wild-type B16 melanoma challenge. The results indicated that the dual-modified vaccine could induce a potent tumor-antigen-specific immune response in addition to an increase of non-specific immunity. This study offers a novel approach to bridging specific and non-specific immunity for cancer therapy. [source]