bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential Effects of Delivery of Omega-3 Fatty Acids to Human Cancer Cells by Low-Density Lipoproteins
versus
Albumin
Authors: Edwards Iris J. , Berquin Isabelle M. , Sun Haiguo , O’Flaherty Joseph T. , Daniel Larry W. , Thomas Michael J. , Rudel Lawrence L. , Wykle Robert L. , Chen Yong Q.
Published: September 2005

Purpose: Omega-3 (n-3) fatty acids (FA) have been proposed to confer tumor-inhibitory properties. In vivo, dietary FA are delivered to tumor cells by two main routes: low-density lipoproteins (LDL) and albumin complexes. High FA concentration in LDL and up-regulation of LDL receptors in tumor cells suggest that the LDL receptor pathway may be the major route for FA delivery. We compared effects of n-3FA delivered to human cancer cells by LDL and albumin.

Experimental Design: LDL was isolated from plasma of African Green monkeys fed diets enriched in fish oil (n-3 FA) or linoleic acid (n-6FA) and used to deliver FA to MCF-7 and PC3 cancer cells. Cell proliferation, apoptosis, and changes in global gene expression were monitored.

Results: Both LDL and albumin were effective in delivering FA to tumor cells and modifying the composition of cell phospholipids. The molar ratio of 20:4 (n-6) to 20:5 (n-3) in phosphatidylcholine and phosphatidylethanolamine was profoundly decreased. Although cell phospholipids were similarly modified by LDL and albumin-delivered FA, effects on cell proliferation and on transcription were markedly different. LDL-delivered n-3 FA were more effective at inhibiting cell proliferation and inducing apoptosis. Expression microarray profiling showed that a significantly higher number of genes were regulated by LDL-delivered than albumin-delivered n-3 FA with little overlap between the two sets of genes.

Conclusions: These results show the importance of the LDL receptor pathway in activating molecular mechanisms responsible for the tumor inhibitory properties of n-3FA.
2-Methoxyestradiol Inhibits Hypoxia-Inducible Factor 1α, Tumor Growth, and Angiogenesis and Augments Paclitaxel Efficacy in Head and Neck Squamous Cell Carcinoma
Authors: Ricker Justin L. , Chen Zhong , Yang Xin Ping , Pribluda Victor S. , Swartz Glenn M. , Van Waes Carter
Published: September 2005

Purpose: Head and neck squamous cell carcinomas have been reported to overexpress hypoxia-inducible factor (HIF)-1α, a transcription factor that promotes expression of angiogenesis factors and resistance to programmed and therapy-induced cell death. 2-Methoxyestradiol (2ME2) is a natural compound with HIF-1α inhibitory activity that is currently being evaluated in phase 1 and 2 clinical trials for advanced solid tumors and multiple myeloma. To our knowledge, this is the first study to evaluate the effects of 2ME2 in head and neck squamous cell carcinoma.

Experimental Design: In the present study, we investigated the effects of 2ME2 alone and in combination with paclitaxel, an active agent in recurrent or advanced head and neck squamous cell carcinoma.

Results: 2ME2 exhibited antiproliferative and cytotoxic effects in a panel of five head and neck squamous cell carcinoma cell lines in the 0.5 to 10 μmol/L range, including induction of G2-M blockade, caspase-3/7 activation, and apoptosis at 48 hours. 2ME2 resulted in decreased nuclear HIF-1α–binding activity and affected the expression of downstream genes, such as bid, a proapoptotic bcl-2 family member, and vascular endothelial growth factor, a proangiogenic cytokine. The up-regulation of Bid (57.5% at 12 hours, P < 0.0006) and inhibition of vascular endothelial growth factor secretion (57.7% at 24 hours, P < 0.015; and 50.3% at 48 hours, P < 0.0006) could be partially attributed to the effects on HIF-1α, because HIF-1α small interfering RNAs produced similar effects. Finally, in vivo, in a xenograft model of head and neck squamous cell carcinoma using UM-SCC-11A cells, 2ME2 exhibited antitumor and antiangiogenic activity, as measured by CD31 immunostaining.

Conclusions: These results provide support for the use of 2ME2 in combination with paclitaxel for the treatment of recurrent or advanced head and neck squamous cell carcinoma.
Approval Summary
Authors: Dagher Ramzi , Li Ning , Abraham Sophia , Rahman Atiqur , Sridhara Raji , Pazdur Richard
Published: September 2005

Purpose: Docetaxel, a taxane previously approved for the treatment of breast cancer and non–small cell lung cancer, was approved by the United States Food and Drug Administration on May 19, 2004 for use in combination with prednisone for the treatment of metastatic androgen-independent (hormone-refractory) prostate cancer. The purpose of this summary is to review the database supporting this approval.

Experimental Design: In a randomized, global study enrolling 1,006 patients, two schedules of docetaxel were compared with mitoxantrone + prednisone as follows: MTZ q 3w, mitoxantrone 12 mg/m2 every 21 days + prednisone 5 mg twice a day for a total of 10 cycles; TXT q 3w, docetaxel 75 mg/m2 every 21 days + prednisone 5 mg twice a day for a total of 10 cycles; and TXT qw, docetaxel 30 mg/m2 days 1, 8, 15, 22, and 29 every 6 weeks + prednisone 5 mg twice a day for a total of 5 cycles.

Results: There was a statistically significant overall survival advantage shown for the TXT q 3w arm over MTZ q 3w (median survival 18.9 months versus 16.5 months, P = 0.0094). No overall survival advantage was shown for TXT qw compared with MTZ q 3w. The most commonly occurring adverse events included anemia, neutropenia, infection, nausea, sensory neuropathy, fluid retention, alopecia, nail changes, diarrhea, and fatigue.

Conclusions: This report describes the Food and Drug Administration review supporting this first approval of a combination therapy for hormone-refractory prostate cancer based on demonstration of a survival benefit.
ADAM8 as a Novel Serological and Histochemical Marker for Lung Cancer
Authors: Ishikawa Nobuhisa , Daigo Yataro , Yasui Wataru , Inai Kouki , Nishimura Hitoshi , Tsuchiya Eiju , Kohno Nobuoki , Nakamura Yusuke
Published: September 2005

Purpose and Experimental Design: We have been investigating genes involved in pulmonary carcinogenesis by examining gene expression profiles of non–small-cell lung cancers to identify molecules that might serve as diagnostic markers or targets for development of new molecular therapies. A gene encoding ADAM8, a disintegrin and metalloproteinase domain-8, was selected as a candidate for such molecule. Tumor tissue microarray was applied to examine expression of ADAM8 protein in archival lung cancer samples from 363 patients. Serum ADAM8 levels of 105 lung cancer patients and 72 controls were also measured by ELISA. A role of ADAM8 in cellular motility was examined by Matrigel assays.

Results: ADAM8 was abundantly expressed in the great majority of lung cancers examined. A high level of ADAM8 expression was significantly more common in advanced-stage IIIB/IV adenocarcinomas than in adenocarcinomas at stages I–IIIA. Serum levels of ADAM8 were significantly higher in lung cancer patients than in healthy controls. The proportion of the serum ADAM8-positive cases defined by our criteria was 63% and that for carcinoembryonic antigen was 57%, indicating equivalent diagnostic power of these two markers. A combined assay using both ADAM8 and carcinoembryonic antigen increased sensitivity because 80% of the lung cancer patients were then diagnosed as positive, whereas only 11% of 72 healthy volunteers were falsely diagnosed as positive. In addition, exogenous expression of ADAM8 increased the migratory activity of mammalian cells, an indication that ADAM8 may play a significant role in progression of lung cancer.

Conclusions: Our data suggest that ADAM8 should be useful as a diagnostic marker and probably as a therapeutic target.
Prognostic Impact of Hypoxia-Inducible Factors 1α and 2α in Colorectal Cancer Patients
Authors: Yoshimura Hiroshi , Dhar Dipok Kumar , Kohno Hitoshi , Kubota Hirofumi , Fujii Toshiyuki , Ueda Shuhei , Kinugasa Shoichi , Tachibana Mitsuo , Nagasue Naofumi
Published: September 2005

Purpose: Angiogenesis plays an important role in a multitude of biological processes including those of tumorigenesis and cancer progression. Hypoxia is the prime driving factor for tumor angiogenesis and the family of hypoxia-inducible factors (HIFs) plays a pivotal role in this process. The role of HIF in tumor angiogenesis has been underscored in different carcinomas but yet to be reported for colorectal carcinomas.

Experimental Design: In this study, we examined HIF [HIF-1α (HIF1) and HIF-2α (HIF2)] expression in 87 curatively resected colorectal carcinoma samples, and the results were correlated with clinicopathological factors, microvessel density, cyclooxygenase 2 expression, and patient prognosis.

Results: HIF1 (44.8%) was more frequently expressed than HIF2 (29.9%). Most of the clinicopathological factors representing the tumor aggressiveness were significantly correlated with overexpression of HIF2 but not with HIF1 expression. HIF2 expression had direct correlation with microvessel density and cyclooxygenase 2 expression. and, in contrast, HIF1 expression had a weak but significant inverse correlation in T1 and T2 tumors only. HIF2 expression alone and the combined expression of HIF1 and HIF2 had significant impact on patient survival. In the multivariate analysis, however, only the combined expression of HIF1 and HIF2 remained independently significant.

Conclusions: Taken together, our results suggest that HIF2 expression may play an important role in angiogenesis and that the combined expression of HIF1 and HIF2 may play an important role in tumor progression and prognosis of colorectal carcinomas. Therefore, HIF expression could be a useful target for therapeutic intervention.
Artificial Neural Networks Analysis of Surface-Enhanced Laser Desorption/Ionization Mass Spectra of Serum Protein Pattern Distinguishes Colorectal Cancer from Healthy Population
Authors: Chen Yi-ding , Zheng Shu , Yu Jie-kai , Hu Xun
Published: September 2005

Purpose: The low specificity and sensitivity of the carcinoembryonic antigen test makes it not an ideal biomarker for the detection of colorectal cancer. We developed and evaluated a proteomic approach for the simultaneous detection and analysis of multiple proteins for distinguishing individuals with colorectal cancer from healthy individuals.

Experimental Design: We subjected serum samples (including 55 colorectal cancer patients and 92 age- and sex-matched healthy individuals) from 147 individuals, for analysis by surface-enhanced laser desorption/ionization (SELDI) mass spectrometry. Peaks were detected with Ciphergen SELDI software version 3.0. Using a multilayer artificial neural network with a back propagation algorithm, we developed a classifier for separating the colorectal cancer groups from the healthy groups.

Results: The artificial neural network classifier separated the colorectal cancer from the healthy samples, with a sensitivity of 91% and specificity of 93%. Four top-scored peaks, at m/z of 5,911, 8,930, 8,817, and 4,476, were finally selected as the potential “fingerprints” for detection of colorectal cancer.

Conclusions: The combination of SELDI-TOF mass spectrometry with the artificial neural networks in the analysis of serum protein yields significantly higher sensitivity and specificity values for the detection and diagnosis of colorectal cancer.
Histone deacetylase inhibitors induce G2-checkpoint arrest and apoptosis in cisplatinum-resistant ovarian cancer cells associated with overexpression of the Bcl-2–related protein Bad
Authors: Strait Kevin A. , Warnick C. Terry , Ford Clyde D. , Dabbas Bashar , Hammond Elizabeth H. , Ilstrup Sarah J.
Published: September 2005

Trichostatin A produces predominantly G1 cell-cycle blockade and differentiation of the cisplatinum-sensitive A2780 ovarian cancer cell line. Given the propensity of ovarian tumors to become resistant to cisplatinum, often leading to cross-resistance to other agents, we have extended these observations by examining how the emergence of resistant phenotypes in A2780 cells affects the actions of histone deacetylase (HDAC) inhibitors. Trichostatin A exposure (100 ng/mL, 24 hours) induced ultrastructural differentiation of the “intrinsically” cisplatinum-resistant A2780-9M subline, with the reappearance of intercellular junctions and lumina containing primitive microvilli. Similar trichostatin A exposure in the acquired resistance A2780CP cells produced minimal differentiation consisting of occasional weak intercellular junctions. Independent of the differences in trichostatin A–induced differentiation, in both resistant sublines trichostatin A produced a similar reduction in cell viability, by >90%, within 5 days of treatment. Diminished viability in both A2780-9M and CP cells was associated with the absence of cell cycle arrest in G1, resulting in predominant G2-checkpoint arrest accompanied by a 10- to 20-fold increase in Annexin V binding and the reemergence of apoptosis. Similar cell cycle arrests and apoptosis were also observed using other HDAC inhibitors and in other resistant ovarian cancer cell lines (OVCAR-3 and SK-OV-3). Trichostatin A–induced apoptosis in resistant cells is in sharp contrast to its effects on the parental cisplatinum-sensitive A2780 and normal MRC-5 fibroblast cell lines (predominant cycle arrest in G1 with no detectable apoptosis). Western immunoblot analysis indicated trichostatin A triggers apoptosis in resistant ovarian cancer cells via p53-independent activation of the intrinsic “mitochondrial” pathway, commensurate with induction of the Bcl-2–related protein Bad. These results suggest cisplatinum resistance alters the effects of HDAC inhibition through a shift in cell cycle arrest from the G1 to the G2 checkpoint and reactivation of the intrinsic mitochondrial apoptotic cascade.
Expression of multidrug transporterMRP4/ABCC4is a marker of poor prognosis in neuroblastoma and confers resistance to irinotecanin vitro
Authors: Norris Murray D. , Smith Janice , Tanabe Kara , Tobin Peter , Flemming Claudia , Scheffer George L. , Wielinga Peter , Cohn Susan L. , London Wendy B. , Marshall Glenn M. , Allen John D. , Haber Michelle
Published: September 2005

Members of the multidrug resistance–associated protein (MRP) family of transporters are believed to contribute to cytotoxic drug resistance and chemotherapy failure. We observed frequent MRP4 overexpression in aggressive primary neuroblastoma, a disease for which we have previously shown MRP1 to be a prognostic indicator. High MRP4 expression correlated with MYCN oncogene amplification and was significantly associated with poor clinical outcome. Although MRP4 is known to transport some nucleoside analogues, it has not previously been associated with resistance to drugs used to treat solid tumors. We now show that it mediates substantial resistance in vitro to the topoisomerase I poison irinotecan/CPT-11 and its active metabolite SN-38. These results suggest that MRP4 will be a useful prognostic marker for neuroblastoma and that clinical trials of irinotecan as a neuroblastoma treatment should monitor MRP4 expression. The same may be true for other tumor types expressing high levels of the transporter.
Dehydroxymethylepoxyquinomicin, a novel nuclear factor-κB inhibitor, induces apoptosis in multiple myeloma cells in an IκBα-independent manner
Authors: Tatetsu Hiro , Okuno Yutaka , Nakamura Miki , Matsuno Fumihiko , Sonoki Takashi , Taniguchi Izumi , Uneda Shima , Umezawa Kazuo , Mitsuya Hiroaki , Hata Hiroyuki
Published: September 2005

Nuclear factor-κB (NF-κB) is constitutively activated in multiple myeloma cells. Several proteasome inhibitors have been shown to be effective against multiple myeloma and may act by inhibiting degradation of IκBα. Here, we examined the biological effects of a new type of NF-κB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ), which is reported to directly inhibit the cytoplasm-to-nucleus translocation of NF-κB. A multiple myeloma cell line, 12PE, which is defective for IκBα protein, was utilized to determine if IκBα is concerned with the action of DHMEQ. Meanwhile, U266 was used as a multiple myeloma cell line with normal IκBα. A proteasome inhibitor, gliotoxin, which is an inhibitor of degradation of phosphorylated IκBα, failed to inhibit translocation of NF-κB in 12PE. In contrast, DHMEQ equally inhibited translocation of NF-κB to the nucleus and induced apoptosis to both multiple myeloma cell lines, suggesting that apoptosis resulting from DHMEQ is IκBα independent. DHMEQ also induced apoptosis in freshly isolated multiple myeloma cells. After DHMEQ treatment, cleavage of caspase-3 and down-regulation of cyclin D1 were observed in both cell lines. In addition, administration of DHMEQ resulted in a significant reduction in tumor volume in a plasmacytoma mice model compared with control mice. Our results show that DHMEQ could potentially be a new type of molecular target agent for multiple myeloma.
Plasma vascular endothelial growth factor and interleukin-8 as biomarkers of antitumor efficacy of a prototypical erbB family tyrosine kinase inhibitor
Authors: Christensen James G. , Vincent Patrick W. , Klohs Wayne D. , Fry David W. , Leopold Wilbur R. , Elliott William L.
Published: September 2005

CI-1033 (N-[4-[N-(3-chloro-4-fluorophenyl)amino-7-[3-(4-morpholynyl)propoxy]quinazolin-6-yl]acrylamide, PD 0183805-mesylate salt) was identified as a potent, selective inhibitor of erbB family tyrosine kinases, which are overexpressed in a number of solid tumors and have been shown to be involved in tumor progression. Because objective response of clinical patients to erbB-targeted therapies like CI-1033 has been observed only in a subset of cancer patients that exhibit the intended molecular targets, much emphasis has been placed on the identification of biomarkers of antitumor efficacy. Vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) were considered as potential biomarkers for CI-1033 due to ease of detection in patient plasma and showed roles in angiogenesis and cancer progression and positive regulation by the erbB receptor family. In the present studies, mice bearing established xenografts (A431 epidermoid carcinoma, H125 non–small cell lung carcinoma, SF767 glioblastoma, and MDA-MB-468 mammary carcinoma) were treated with efficacious and subefficacious doses of CI-1033, and plasma levels and xenograft gene expression of VEGF and IL-8 were evaluated. Oral administration of CI-1033 to tumor-bearing mice at efficacious doses resulted in markedly decreased levels of VEGF and/or IL-8 plasma levels and tumor mRNA levels relative to vehicle-treated control mice in xenograft models that exhibited evaluable levels of these markers. In contrast, subefficacious doses of CI-1033 did not significantly affect VEGF or IL-8 levels in any of the xenograft models. These studies indicate that plasma VEGF and IL-8 may have use as biomarkers of antitumor efficacy for epidermal growth factor receptor/erbB–targeted therapies such as CI-1033 and suggest that further clinical study of these markers in cancer patients are warranted.
A phase I clinical trial of a ribozyme-based angiogenesis inhibitor targeting vascular endothelial growth factor receptor-1 for patients with refractory solid tumors
Authors: Weng David E. , Masci Paul A. , Radka Susan F. , Jackson T. Elise , Weiss Patricia A. , Ganapathi Ram , Elson Paul J. , Capra William B. , Parker Vann P. , Lockridge Jennifer A. , Cowens J. Wayne , Usman Nassim , Borden Ernest C.
Published: September 2005

Purpose: This study intended to determine the maximum tolerated dose, safety, pharmacokinetic variables, clinical response, and pharmacodynamic markers of daily s.c. administration of Angiozyme. Patients and Methods: Patients with refractory solid tumors were enrolled in a dose escalation and expanded cohort design. Dose escalation involved cohorts of patients at doses of 10, 30, 100, or 300 mg/m2/d for 29 days. A second component enrolled 15 additional patients at a daily dose of 100 mg/m2. Patients were eligible to continue on therapy until disease progression. Results: Thirty-one patients were enrolled and 28 were evaluable (range, 29–505 days; median, 89.5 days). A maximum tolerated dose was not defined by toxicity but rather by the maximal deliverable dose of 300 mg/m2/d. Grade 1 to 2 injection site reactions were the most common toxicities. One patient in the 300 mg/m2 group experienced a reversible grade 3 injection site reaction. Angiozyme showed dose-dependent plasma concentrations with good bioavailability. Surrogate markers showed Angiozyme localization in tumor biopsies and a significant increase in serum von Willebrand factor antigen, a marker for endothelial cell dysfunction. Although Angiozyme-reactive antibody production was noted for some patients, no antibody-related adverse events were noted. Seven of 28 (25%) evaluable patients had stable disease for ≥6 months, with the longest treatment duration of ≥16 months. Two patients (nasopharyngeal carcinoma and melanoma) showed minor responses. Conclusion: Angiozyme was well tolerated with satisfactory pharmacokinetic variables for daily s.c. dosing. Results have provided the basis for subsequent clinical trials of this first-of-class biologically targeted therapeutic.
Anti-gene peptide nucleic acid specifically inhibits MYCN expression in human neuroblastoma cells leading to cell growth inhibition and apoptosis
Authors: Tonelli Roberto , Purgato Stefania , Camerin Consuelo , Fronza Raffaele , Bologna Fabrizio , Alboresi Simone , Franzoni Monica , Corradini Roberto , Sforza Stefano , Faccini Andrea , Shohet Jason M. , Marchelli Rosangela , Pession Andrea
Published: September 2005

We developed an anti-gene peptide nucleic acid (PNA) for selective inhibition of MYCN transcription in neuroblastoma cells, targeted against a unique sequence in the antisense DNA strand of exon 2 of MYCN and linked at its NH2 terminus to a nuclear localization signal peptide. Fluorescence microscopy showed specific nuclear delivery of the PNA in six human neuroblastoma cell lines: GI-LI-N and IMR-32 (MYCN-amplified/overexpressed); SJ-N-KP and NB-100 (MYCN-unamplified/low-expressed); and GI-CA-N and GI-ME-N (MYCN-unamplified/unexpressed). Antiproliferative effects were observable at 24 hours (GI-LI-N, 60%; IMR-32, 70%) and peaked at 72 hours (GI-LI-N, 80%; IMR-32, 90%; SK-N-KP, 60%; NB-100, 50%); no reduction was recorded for GI-CA-N and GI-ME-N (controls). In MYCN-amplified/overexpressed IMR-32 cells and MYCN-unamplified/low-expressed SJ-N-KP cells, inhibition was recorded of MYCN mRNA (by real-time PCR) and N-Myc (Western blotting); these inhibitory effects increased over 3 days after single treatment in IMR-32. Anti-gene PNA induced G1-phase accumulation (39–53%) in IMR-32 and apoptosis (56% annexin V–positive cells at 24 hours in IMR-32 and 22% annexin V–positive cells at 48 hours in SJ-N-KP). Selective activity of the PNA was shown by altering three point mutations, and by the observation that an anti-gene PNA targeted against the noncoding DNA strand did not exert any effect. These findings could encourage research into development of an anti-gene PNA–based tumor-specific agent for neuroblastoma (and other neoplasms) with MYCN expression.
Parthenolide and sulindac cooperate to mediate growth suppression and inhibit the nuclear factor-κB pathway in pancreatic carcinoma cells
Authors: Yip-Schneider Michele T. , Nakshatri Harikrishna , Sweeney Christopher J. , Marshall Mark S. , Wiebke Eric A. , Schmidt C. Max
Published: September 2005

Activation of the transcription factor nuclear factor-κB (NF-κB) has been implicated in pancreatic tumorigenesis. We evaluated the effect of a novel NF-κB inhibitor, parthenolide, a sesquiterpene lactone isolated from the herb feverfew, in three human pancreatic tumor cell lines (BxPC-3, PANC-1, and MIA PaCa-2). Parthenolide inhibited pancreatic cancer cell growth in a dose-dependent manner with substantial growth inhibition observed between 5 and 10 μmol/L parthenolide in all three cell lines. Parthenolide treatment also dose-dependently increased the amount of the NF-κB inhibitory protein, IκB-α, and decreased NF-κB DNA binding activity. We have previously shown that nonsteroidal anti-inflammatory drugs (NSAID) suppress the growth of pancreatic cancer cells. To determine whether inhibition of the NF-κB pathway by parthenolide could sensitize pancreatic cancer cells to NSAID inhibition, BxPC-3, PANC-1, and MIA PaCa-2 cells were treated with parthenolide and the NSAID sulindac, either alone or in combination. Treatment with the combination of parthenolide and sulindac inhibited cell growth synergistically in MIA PaCa-2 and BxPC-3 cells and additively in PANC-1 cells. In addition, treatment with the parthenolide/sulindac combination lowered the threshold for apoptosis. Increased levels of IκB-α protein were detected, especially in MIA PaCa-2 cells, after treatment with parthenolide and sulindac compared with each agent alone. Similarly, decreased NF-κB DNA binding and transcriptional activities were detected in cells treated with the combination compared with the single agents, demonstrating cooperative targeting of the NF-κB pathway. These data provide preclinical support for a combined chemotherapeutic approach with NF-κB inhibitors and NSAIDs for the treatment of pancreatic adenocarcinoma.
Interaction between epidermal growth factor receptor– and cyclooxygenase 2–mediated pathways and its implications for the chemoprevention of head and neck cancer
Authors: Choe Mi Sun , Zhang Xin , Shin Hyung Ju C. , Shin Dong M. , Chen Zhuo (Georgia)
Published: September 2005

Head and neck squamous cell carcinoma is a well-known model for chemoprevention studies because of its field cancerization effect, its multistep carcinogenesis process, and the easy accessibility of biopsies to target lesions. With new understandings of head and neck carcinogenesis and the development of molecular targeted therapy, chemoprevention trials for head and neck squamous cell carcinoma have been rapidly updated. Cyclooxygenase-2 (COX-2) and epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors are gaining significant attention as potential chemopreventive agents. Both COX-2 and EGFR are involved in head and neck carcinogenesis. Targeting COX-2 and EGFR separately has shown promising antitumor activity. Recently, combinations of COX-2 and EGFR tyrosine kinase inhibitors have been reported to show synergistic/additive effects in preclinical studies. Because COX-2 and EGFR tyrosine kinase inhibitors are toxic as single agents in clinical trials, the combination of COX-2 and EGFR tyrosine kinase inhibitors used at lower doses seems more promising than monotherapy with either as a novel strategy in head and neck cancer chemoprevention.
Transfection of melanoma cells with antisensePAX3oligonucleotides additively complements cisplatin-induced cytotoxicity
Authors: He Shu-Jie , Stevens Graham , Braithwaite Antony W. , Eccles Michael R.
Published: September 2005

Advanced melanoma is difficult to treat, in part because of greater resistance to therapy compared with other cancer types. The mechanisms underlying this resistance are not well-understood. One factor that is reported to be involved in melanoma cell survival is PAX3, a transcription factor normally expressed during embryonic development, and which is critically required for development of neural crest-derivatives, including skin melanocytes. PAX3 expression is deregulated in primary melanomas and most melanoma cell lines. Here we have investigated whether targeting PAX3 expression in melanoma cell lines together with chemotherapeutic treatment increases susceptibility to therapeutic cell death. Using PAX3-specific antisense oligodeoxynucleotides (PAX3-AS) to treat melanoma cell lines in vitro, we showed dose-dependent reduction of proliferation of melanoma cells, and induction of apoptosis compared with control treatments. Induction of apoptosis was accompanied by the induction of active caspase-3 in UACC62 and M14 cells, and p53 protein in UACC62 cells. Treatment of melanoma cells with cisplatin induces DNA damage and cytotoxicity, which is thought to be via p53-dependent and -independent mechanisms. Treatment of either p53 mutant (M14) or wild-type (UACC62) melanoma cells with cisplatin, and varying doses of PAX3-AS, resulted in percentages of cells undergoing apoptosis equivalent to the sum of the individual treatments, irrespective of mutation status [e.g., UACC62, 43.8% (1 μmol/L PAX3-AS), 30.1% (20 μmol/L cisplatin), 69.6% (PAX3-AS + cisplatin); M14, 12.6% (1 μmol/L PAX3-AS), 41.5% (40 μmol/L cisplatin), 50.2% (PAX3-AS + cisplatin)]. These data suggest that treatment of melanoma cells with PAX3-AS complements cytotoxicity induced by cisplatin.
Application of thermally responsive polypeptides directed against c-Myc transcriptional function for cancer therapy
Authors: Bidwell Gene L. , Raucher Drazen
Published: September 2005

Elastin-like polypeptides are biopolymers composed of the pentapeptide repeat Val-Pro-Gly-Xaa-Gly. Elastin-like polypeptides are soluble in aqueous solution below their transition temperature, but they hydrophobically collapse and aggregate when the temperature is raised above the transition temperature. Previous studies have suggested that the aggregation of these polypeptides in response to externally applied hyperthermia may be exploited in the use of elastin-like polypeptide for thermally targeted drug delivery. This work shows the application of elastin-like polypeptide as a delivery vehicle for a short peptide that can inhibit the transcriptional function of a specific oncogene. The coding sequence for elastin-like polypeptide was modified by the addition of the membrane translocating sequence penetratin and a peptide derived from helix 1 of the helix-loop-helix region of c-Myc (H1-S6A,F8A), known to inhibit c-Myc transcriptional function. The designed polypeptide (Pen-ELP-H1) was then expressed and purified from Escherichia coli. Cellular uptake of Pen-ELP-H1 is enhanced by both the penetratin sequence and by the hyperthermia-induced phase transition as shown by flow cytometry studies. Using immunofluorescence and reverse transcription-PCR, we show that Pen-ELP-H1 is able to disrupt the nuclear localization of c-Myc and inhibit transcriptional activation by c-Myc. Cell proliferation studies showed that Pen-ELP-H1 inhibits growth of MCF-7 cells. Furthermore, the use of hyperthermia increased the antiproliferative effect of a thermally responsive Pen-ELP-H1 ∼2-fold compared with a nonthermally responsive control polypeptide. These studies show that genetically engineered elastin-like polypeptide carriers may provide a new way to thermally target specific oncogene inhibitors to solid tumors.
Cyclin A–associated kinase activity is needed for paclitaxel sensitivity
Authors: Takahashi Takeshi , Yamasaki Fumiyuki , Sudo Tamotsu , Itamochi Hiroaki , Adachi Susumu , Tamamori-Adachi Mimi , Ueno Naoto T.
Published: September 2005

Cyclin A–associated kinases, such as cyclin-dependent kinase 2 (CDK2), participate in regulating cellular progression from G1 to S to G2, and CDK2 has also been implicated in the transition to mitosis. The antitumor properties of CDK inhibitors, alone or in combination with taxanes, are currently being examined in clinical trials. Here, we examined whether the activity of kinases associated with cyclin A (such as CDK2) is important in determining cellular sensitivity to paclitaxel, a taxane and mitotic inhibitor used in chemotherapy for breast and ovarian cancer. We used adenoviral suppression or overexpression to manipulate the expression of CDK2 and cyclin A in one breast cancer and three ovarian cancer cell lines with different sensitivities to paclitaxel and assessed protein expression, kinase activity, cell cycle distribution, and sensitivity to paclitaxel. Transfection of a dominant-negative (DN)-CDK2 evoked resistance to paclitaxel by preventing cellular progression to mitosis through loss of CDK1 activity. Reexpression of wild-type CDK2 in DN-CDK2–transfected cancer cells restored CDK2 activity but not paclitaxel sensitivity. However, expression of cyclin A in DN-CDK2–transfected cells restored their sensitivity to paclitaxel. Although CDK2 activity was not directly involved in paclitaxel sensitivity, cyclin A–associated kinases did up-regulate CDK1 via phosphorylation. We conclude that cyclin A–associated kinase activity is required for these cells to enter mitosis and undergo paclitaxel-induced cell death. Combining taxane chemotherapy with any drug targeting cyclin A–associated kinases (e.g., pure CDK2 inhibitors) should be done with caution, if at all, because of the potential for enhancing taxane resistance.
Pentameric procyanidin from Theobroma cacao selectively inhibits growth of human breast cancer cells
Authors: Ramljak Danica , Romanczyk Leo J. , Metheny-Barlow Linda J. , Thompson Nicole , Knezevic Vladimir , Galperin Mikhail , Ramesh Arun , Dickson Robert B.
Published: September 2005

A naturally occurring, cocoa-derived pentameric procyanidin (pentamer) was previously shown to cause G0/G1 cell cycle arrest in human breast cancer cells by an unknown molecular mechanism. Here, we show that pentamer selectively inhibits the proliferation of human breast cancer cells (MDA MB-231, MDA MB-436, MDA MB-468, SKBR-3, and MCF-7) and benzo(a)pyrene-immortalized 184A1N4 and 184B5 cells. In contrast, normal human mammary epithelial cells in primary culture and spontaneously immortalized MCF-10A cells were significantly resistant. We evaluated whether this differential response to pentamer may involve depolarization of the mitochondrial membrane. Pentamer caused significant depolarization of mitochondrial membrane in MDA MB231 cells but not the more normal MCF-10A cells, whereas other normal and tumor cell lines tested gave variable results. Further investigations, using a proteomics approach with pentamer-treated MDA MB-231, revealed a specific dephosphorylation, without changes in protein expression, of several G1-modulatory proteins: Cdc2 (at Tyr15), forkhead transcription factor (at Ser256, the Akt phosphorylation site) and p53 (Ser392). Dephosphorylation of p53 (at Ser392) by pentamer was confirmed in MDA MB-468 cells. However, both expression and phosphorylation of retinoblastoma protein were decreased after pentamer treatment. Our results show that breast cancer cells are selectively susceptible to the cytotoxic effects of pentameric procyanidin, and suggest that inhibition of cellular proliferation by this compound is associated with the site-specific dephosphorylation or down-regulation of several cell cycle regulatory proteins.
Targeted delivery to PEPT1-overexpressing cells: Acidic, basic, and secondary floxuridine amino acid ester prodrugs
Authors: Landowski Christopher P. , Vig Balvinder S. , Song Xueqin , Amidon Gordon L.
Published: September 2005

Floxuridine is a clinically proven anticancer agent in the treatment of metastatic colon carcinomas and hepatic metastases. However, prodrug strategies may be necessary to improve its physiochemical properties and selectivity and to reduce undesirable toxicity effects. Previous studies with amino acid ester prodrugs of nucleoside drugs targeted to the PEPT1 transporter coupled with recent findings of the functional expression of the PEPT1 oligopeptide transporter in pancreatic adenocarcinoma cell lines suggest the potential of PEPT1 as therapeutic targets for cancer treatment. In this report, we show the feasibility of achieving enhanced transport and selective antiproliferative action of amino acid ester prodrugs of floxuridine in cell systems overexpressing PEPT1. All prodrugs exhibited affinity for PEPT1 (IC50, 1.1–2.3 mmol/L). However, only the prolyl and lysyl prodrugs exhibited enhanced uptake (2- to 8-fold) with HeLa/PEPT1 cells compared with HeLa cells, suggesting that the aspartyl prodrugs are PEPT1 inhibitors. The selective growth inhibition of Madine-Darby canine kidney (MDCK)/PEPT1 cells over MDCK cells by the prodrugs was consistent with the extent of their PEPT1-mediated transport. All ester prodrugs hydrolyzed to floxuridine fastest in Caco-2 cell and MDCK homogenates and slower in human plasma and were most chemically stable in pH 6.0 buffer. Prolyl and lysyl prodrugs were relatively less stable compared with aspartyl prodrugs in buffers and in cell homogenates. The results suggest that optimal design for targeted delivery would be possible by combining both stability and transport characteristics afforded by the promoiety.
Raf kinase as a target for anticancer therapeutics
Authors: Sridhar Srikala S. , Hedley David , Siu Lillian L.
Published: September 2005

The Ras-Raf-MEK-ERK (ERK) pathway is a logical therapeutic target because it represents a common downstream pathway for several key growth factor tyrosine kinase receptors which are often mutated or overexpressed in human cancers. Although considered mainly growth-promoting, in certain contexts, this pathway also seems to be apoptosis-suppressing. Several novel agents targeting this pathway have now been developed and are in clinical trials. One of the most interesting new agents is BAY 43-9006. Although initially developed as a Raf kinase inhibitor, it can also target several other important tyrosine kinases including VEGFR-2, Flt-3, and c-Kit, which contributes to its antiproliferative and antiangiogenic properties. To date, encouraging results have been seen with BAY 43-9006, particularly in renal cell cancers which are highly vascular tumors. This review will provide an overview of the ERK signaling pathway in normal and neoplastic tissue, with a specific focus on novel therapies targeting the ERK pathway at the level of Raf kinase.
Cell cycle checkpoint signaling involved in histone deacetylase inhibition and radiation-induced cell death
Authors: Nome Ragnhild V. , Bratland Åse , Harman Gunhild , Fodstad Øystein , Andersson Yvonne , Ree Anne Hansen
Published: September 2005

In breast cancer, radiation has a central role in the treatment of brain metastasis, although tumor sensitivity might be limited. The tumor cell defense response to ionizing radiation involves activation of cell cycle checkpoint signaling. Histone deacetylase (HDAC) inhibitors, agents that cause hyperacetylation of histone proteins and thereby aberrations in the chromatin structure, may also override the DNA damage defense response and facilitate the radiation-induced mitotic cell death. In experimental metastasis models, the human breast carcinoma cell line MA-11 invariably disseminates to the central nervous system. We compared profiles of in vitro MA-11 cell cycle response to ionizing radiation and HDAC inhibition. After radiation exposure, the G2-M phase accumulation and the preceding repression of the G2 phase regulatory factors Polo-like kinase-1 and cyclin B1 required intact G2 checkpoint signaling through the checkpoint kinase CHK1, whereas the similar phenotypic changes observed with HDAC inhibition did not. MA-11 cells did not show radiation-induced expression of the G1 cell cycle inhibitor p21, indicative of a defective G1 checkpoint and consistent with a point mutation detected in the tumor suppressor TP53 gene. Increase in the p21 level, however, was observed with HDAC inhibition. Following pretreatment with the HDAC inhibitor, the efficiency of clonogenic regrowth after irradiation was reduced, which is in accordance with the concept of increased probability of mitotic cell death when the chromatin structure is disrupted. Among molecular cell cycle–targeted drugs currently in the pipeline for testing in early-phase clinical trials, HDAC inhibitors may have therapeutic potential as radiosensitizers.
Transcriptional signature of Ecteinascidin 743 (Yondelis, Trabectedin) in human sarcoma cells explanted from chemo-naïve patients
Authors: Martínez Nerea , Sánchez-Beato Margarita , Carnero Amancio , Moneo Victoria , Tercero Juan C. , Fernández Isabel , Navarrete Mercedes , Jimeno José , Piris Miguel A.
Published: September 2005

Ecteinascidin 743 (ET-743; Yondelis, Trabectedin) is a marine anticancer agent that induces long-lasting objective remissions and tumor control in a subset of patients with pretreated/resistant soft-tissue sarcoma. Drug-induced tumor control is achievable in 22% of such patients, but there is no clear indication of the molecular features correlated with clinical sensitivity/resistance to ET-743. Nine low-passage, soft-tissue sarcoma cell lines, explanted from chemo-naïve patients with different patterns of sensitivity, have been profiled with a cDNA microarray containing 6,700 cancer-related genes. The molecular signature of these cell lines was analyzed at baseline and at four different times after ET-743 exposure. The association of levels of TP53 mutation and TP73 expression with ET-743 sensitivity and cell cycle kinetics after treatment was also analyzed. Gene expression profile analysis revealed up-regulation of 86 genes and down-regulation of 244 genes in response to ET-743. The ET-743 gene expression signature identified a group of genes related with cell cycle control, stress, and DNA-damage response (JUNB, ATF3, CS-1, SAT, GADD45B, and ID2) that were up-regulated in all the cell lines studied. The transcriptional signature 72 hours after ET-743 administration, associated with ET-743 sensitivity, showed a more efficient induction of genes involved in DNA-damage response and apoptosis, such as RAD17, BRCA1, PAR4, CDKN1A, and P53DINP1, in the sensitive cell line group. The transcriptional signature described here may lead to the identification of ET-743 downstream mediators and transcription regulators and the proposal of strategies by which ET-743–sensitive tumors may be identified.
The role of IFN regulatory factor-3 in the cytotoxic activity of NS-9, a polyinosinic-polycytidylic acid/cationic liposome complex, against tumor cells
Authors: Uno Tomonori , Hirabayashi Kazuko , Murai Masatoshi , Yano Junichi , Ozato Keiko
Published: September 2005

NS-9 is a complex of polyinosinic-polycytidylic acid and a novel cationic liposome, LIC-101. The complex has strong cytotoxic activity against tumor cells derived from epithelial or fibroblastic cells. We have investigated the mechanism of the cytotoxic activity of NS-9 using knockdown cells in which the expression of proteins of interest was inhibited by RNA interference. NS-9 showed strong cytotoxic activity against knockdown cells with reduced expression of double-stranded RNA-dependent protein kinase, RNase L, or IFN-α/β receptor, but showed no cytotoxic activity against IFN regulatory factor-3 (IRF3) knockdown cells. In IRF3-knockdown cells, NS-9 also did not induce either the DNA fragmentation or the rRNA degradation observed in negative control cells. We conclude that IRF3 plays a crucial role in the cytotoxic activity of NS-9 against tumor cells, whereas RNA-dependent protein kinase, RNase L, or type I IFNs are not important for its activity.
Tissue transglutaminase 2 inhibition promotes cell death and chemosensitivity in glioblastomas
Authors: Yuan Liya , Choi Kihang , Khosla Chaitan , Zheng Xiao , Higashikubo Ryuji , Chicoine Michael R. , Rich Keith M.
Published: September 2005

Tissue transglutaminase 2 belongs to a family of transglutaminase proteins that confers mechanical resistance from proteolysis and stabilizes proteins. Transglutaminase 2 promotes transamidation between glutamine and lysine residues with the formation of covalent linkages between proteins. Transglutaminase 2 also interacts and forms complexes with proteins important in extracellular matrix organization and cellular adhesion. We have identified the novel finding that treatment of glioblastoma cells with transglutaminase 2 inhibitors promotes cell death and enhances sensitivity to chemotherapy. Treatment with either the competitive transglutaminase 2 inhibitor, monodansylcadaverine, or with highly specific small-molecule transglutaminase 2 inhibitors, KCA075 or KCC009, results in induction of apoptosis in glioblastoma cells. Treatment with these transglutaminase 2 inhibitors resulted in markedly decreased levels of the prosurvival protein, phosphorylated Akt, and its downstream targets. These changes promote a proapoptotic profile with altered levels of multiple intracellular proteins that determine cell survival. These changes include decreased levels of the antiapoptotic proteins, survivin, phosphorylated Bad, and phosphorylated glycogen synthetase kinase 3β (GSK-3β), and increased levels of the proapoptotic BH3-only protein, Bim. In vivo studies with s.c. murine DBT glioblastoma tumors treated with transglutaminase 2 inhibitors combined with the chemotherapeutic agent, N-N′-bis (2-chloroethyl)-N-nitrosourea (BCNU), decreased tumor size based on weight by 50% compared with those treated with BCNU alone. Groups treated with transglutaminase 2 inhibitors showed an increased incidence of apoptosis determined with deoxynucleotidyl transferase–mediated biotin nick-end labeling staining. These studies identify inhibition of transglutaminase 2 as a potential target to enhance cell death and chemosensitivity in glioblastomas.
Fibroblast growth factor receptor 3 inhibition by short hairpin RNAs leads to apoptosis in multiple myeloma
Authors: Zhu Lijun , Somlo George , Zhou Bingsen , Shao Jimin , Bedell Victoria , Slovak Marilyn L. , Liu Xiyong , Luo Jianhong , Yen Yun
Published: September 2005

The presence of t(4;14)(p16.3;q32.3) in multiple myeloma cells results in dysregulated expression of the fibroblast growth factor receptor 3 (FGFR3). FGFR3 acts as an oncogene to promote multiple myeloma cell proliferation and antiapoptosis. These encourage the clinical development of FGFR3-specific inhibitors. Three short hairpin RNAs (shRNA) targeting different sites of FGFR3 were selected and subsequently transfected into KMS-11, OPM-2, and NCI-H929 human myeloma cell lines, all of which are characterized by t(4;14) and FGFR3 over expression. The combination of these three shRNAs can effectively inhibit FGFR3 expression in all three cell lines. Sequential immunocytochemistry/fluorescence in situ hybridization was employed to validate that the shRNAs specifically inhibited FGFR3 expression in OPM-2 cells. Decreased expression of B-cell chronic lymphocytic leukemia/lymphoma 2 (BCL2) and myeloid cell leukemia sequence 1 (MCL1) proteins and increased staining of Annexin V–positive cells showed that inhibition of FGFR3 induces apoptosis. After confirming down-regulation of FGFR3 by real-time PCR, HU-133 plus 2.0 array was employed to compare the gene expression profile of shRNA-treated sample with that of the control. Besides the down-regulation of FGFR3, expression of the antiapoptotic genes CFLAR, BCL2, MCL1, and some members of NF-κB family decreased, whereas expression of the proapoptotic genes CYC, BID, CASP2, and CASP6 increased. Microarray results also revealed changes in genes previously implicated in multiple myeloma pathogenesis (RAS, RAF, IL-6R, and VEGF), as well as others (TLR4, KLF4, and GADD45A) not previously linked to multiple myeloma. Our observations indicate that shRNAs can specifically and effectively inhibit FGFR3 expression. This targeted approach may be worth testing in multiple myeloma patients with t(4;14) and FGFR3 overexpression in the future.