Search

PDF file - 1.2MB, Fig. S1. Validation of the sterol pathway targeting siRNA. Fig. S2. Silencing of SC4MOL increased erlotinib-induced apoptosis. Fig. S3. Metabolic effects of SC4MOL silencing and sterols supplementation. Fig. S4. Sterol pathway interactions. Fig. S5. Effects of SC4MOL silencing on EGFR synthesis and I-125 EGF internalization and degradation. Fig. S6. Effects of sterol pathway genes silencing on EGFR endosomal traffic. Fig. S7. Effects of SC4MOL silencing on EGFR ubiquitin conjugation and accumulation in late endosomes. Fig. S8. Supporting data for Figure 5. Fig. S9. Supporting data for Figure 7A. Fig. S10. Analysis of NSDHL expression in malignant and benign epithelial tissues

PDF file - 105K

Esophageal squamous cell carcinoma (ESCC) is an exceptionally drug-resistant tumor with a 5-year survival rate 2-M-phase cell cycle arrest and p53-independent apoptosis associated with caspase cleavage and Noxa induction. Bortezomib also showed excellent activity in organotypic culture and in vivo models of ESCC. Biochemically, bortezomib treatment activated the p38 and c-Jun NH2-termnial kinase stress-activated mitogen-activated protein kinase (MAPK) pathways and induced phospho-H2AX activity. Although H2AX is known to cooperate with c-Jun NH2-termnial kinase to induce apoptosis following UV irradiation, knockdown of H2AX did not abrogate bortezomib-induced apoptosis. Instead, blockade of p38 MAPK signaling, using either small interfering RNA or a pharmacologic inhibitor, reversed bortezomib-induced apoptosis and the up-regulation of Noxa. Radiation therapy is known to activate the p38 MAPK pathway and is a mainstay of ESCC treatment strategies. In a final series of studies, we showed that the coadministration of bortezomib with irradiation led to enhanced p38 MAPK activity and a significant reduction in colony formation. We therefore suggest that p38 MAPK pathway activation is an excellent potential therapeutic strategy in ESCC. It is further suggested that bortezomib could be added to existing ESCC therapeutic regimens. [Mol Cancer Ther 2008;7(9):2866–75]

Supplementary Figures 1-6 from RAD001 (Everolimus) Delays Tumor Onset and Progression in a Transgenic Mouse Model of Ovarian Cancer

Supplementary Figure 1 from The MET Receptor Tyrosine Kinase Is a Potential Novel Therapeutic Target for Head and Neck Squamous Cell Carcinoma

Supplementary Figure 1 from NEDD9 Promotes Oncogenic Signaling in Mammary Tumor Development

Supplementary Figure Legends 1-2, Table Legend 1 from The MET Receptor Tyrosine Kinase Is a Potential Novel Therapeutic Target for Head and Neck Squamous Cell Carcinoma

Supplementary Figure 3 from NEDD9 Promotes Oncogenic Signaling in Mammary Tumor Development

Supplementary Table 1 from NEDD9 Promotes Oncogenic Signaling in Mammary Tumor Development

Supplementary Figure Legends 1-6 from RAD001 (Everolimus) Delays Tumor Onset and Progression in a Transgenic Mouse Model of Ovarian Cancer

Supplementary Figure 2 from NEDD9 Promotes Oncogenic Signaling in Mammary Tumor Development

Large homozygous deletions of 9p21 that inactivate CDKN2A, ARF, and MTAP are common in a wide variety of human cancers. The role for CDKN2A and ARF in tumorigenesis is well established, but whether MTAP loss directly affects tumorigenesis is unclear. MTAP encodes the enzyme methylthioadenosine phosphorylase, a key enzyme in the methionine salvage pathway. To determine if loss of MTAP plays a functional role in tumorigenesis, we have created an MTAP-knockout mouse. Mice homozygous for a MTAP null allele (MtaplacZ) have an embryonic lethal phenotype dying around day 8 postconception. Mtap/MtaplacZ heterozygotes are born at Mendelian frequencies and appear indistinguishable from wild-type mice during the first year of life, but they tend to die prematurely with a median survival of 585 days. Autopsies on these animals reveal that they have greatly enlarged spleens, altered thymic histology, and lymphocytic infiltration of their livers, consistent with lymphoma. Immunohistochemical staining and fluorescence-activated cell sorting analysis indicate that these lymphomas are primarily T-cell in origin. Lymphoma-infiltrated tissues tend to have reduced levels of Mtap mRNA and MTAP protein in addition to unaltered levels of methyldeoxycytidine. These studies show that Mtap is a tumor suppressor gene independent of CDKN2A and ARF. [Cancer Res 2009;69(14):OF5961–8]

Supplementary Figure 1 from Coordinated Functions of E-Cadherin and Transforming Growth Factor β Receptor II In vitro and In vivo

Supplementary Figures 1-3, Table 1 from Mice Heterozygous for Germ-line Mutations in Methylthioadenosine Phosphorylase (MTAP) Die Prematurely of T-Cell Lymphoma

In the past 3 years, altered expression of the HEF1/CAS-L/NEDD9 scaffolding protein has emerged as contributing to cancer metastasis in multiple cancer types. However, whereas some studies have identified elevated NEDD9 expression as prometastatic, other work has suggested a negative role in tumor progression. We here show that the Nedd9-null genetic background significantly limits mammary tumor initiation in the MMTV-polyoma virus middle T genetic model. Action of NEDD9 is tumor cell intrinsic, with immune cell infiltration, stroma, and angiogenesis unaffected. The majority of the late-appearing mammary tumors of MMTV-polyoma virus middle T;Nedd9−/− mice are characterized by depressed activation of proteins including AKT, Src, FAK, and extracellular signal-regulated kinase, emphasizing an important role of NEDD9 as a scaffolding protein for these prooncogenic proteins. Analysis of cells derived from primary Nedd9+/+ and Nedd9−/− tumors showed persistently reduced FAK activation, attachment, and migration, consistent with a role for NEDD9 activation of FAK in promoting tumor aggressiveness. This study provides the first in vivo evidence of a role for NEDD9 in breast cancer progression and suggests that NEDD9 expression may provide a biomarker for tumor aggressiveness. [Cancer Res 2009;69(18):7198–206]

In epithelial cells, E-cadherin plays a key role in cell-cell adhesion, and loss of E-cadherin is a hallmark of tumor progression fostering cancer cell invasion and metastasis. To examine E-cadherin loss in squamous cell cancers, we used primary human esophageal epithelial cells (keratinocytes) as a platform and retrovirally transduced wild-type and dominant-negative forms of E-cadherin into these cells. We found decreased cell adhesion in the cells expressing dominant-negative E-cadherin, thereby resulting in enhanced migration and invasion. To analyze which molecular pathway(s) may modulate these changes, we conducted microarray analysis and found up-regulation of transforming growth factor β receptor II (TβRII) in the wild-type E-cadherin-overexpressing cells, which was confirmed by real-time PCR and Western blot analyses. To investigate the in vivo relevance of this finding, we analyzed tissue microarrays of paired esophageal squamous cell carcinomas and adjacent normal esophagus, and we could show a coordinated loss of E-cadherin and TβRII in ∼80% of tumors. To determine if there may be an E-cadherin-dependent regulation of TβRII, we show the physical interaction of E-cadherin with TβRII and that this is mediated through the extracellular domains of E-cadherin and TβRII, respectively. In addition, TβRI is recruited to this complex. When placed in the context of three-dimensional cell culture, which reflects the physiologic microenvironment, TβRII-mediated cell signaling is dependent upon intact E-cadherin function. Our results, which suggest that E-cadherin regulates TβRII function, have important implications for epithelial carcinogenesis characterized through the frequent occurrence of E-cadherin and TβRII loss. (Cancer Res 2006; 66(20): 9878-85)

Supplementary Figure Legends 1-3 from Mice Heterozygous for Germ-line Mutations in Methylthioadenosine Phosphorylase (MTAP) Die Prematurely of T-Cell Lymphoma

Recurrent/metastatic head and neck cancer remains a devastating disease with insufficient treatment options. We investigated the MET receptor tyrosine kinase as a novel target for the treatment of head and neck squamous cell carcinoma (HNSCC). MET/phosphorylated MET and HGF expression was analyzed in 121 tissues (HNSCC/normal) by immunohistochemistry, and in 20 HNSCC cell lines by immunoblotting. The effects of MET inhibition using small interfering RNA/two small-molecule inhibitors (SU11274/PF-2341066) on signaling, migration, viability, and angiogenesis were determined. The complete MET gene was sequenced in 66 head and neck cancer tissue samples and eight cell lines. MET gene copy number was determined in 14 cell lines and 23 tumor tissues. Drug combinations of SU11274 with cisplatin or erlotinib were tested in SCC35/HN5 cell lines. Eighty-four percent of the HNSCC samples showed MET overexpression, whereas 18 of 20 HNSCC cell lines (90%) expressed MET. HGF overexpression was present in 45% of HNSCC. MET inhibition with SU11274/PF-2341066 abrogated MET signaling, cell viability, motility/migration in vitro, and tumor angiogenesis in vivo. Mutational analysis of 66 tumor tissues and 8 cell lines identified novel mutations in the semaphorin (T230M/E168D/N375S), juxtamembrane (T1010I/R988C), and tyrosine kinase (T1275I/V1333I) domains (incidence: 13.5%). Increased MET gene copy number was present with >10 copies in 3 of 23 (13%) tumor tissues. A greater-than-additive inhibition of cell growth was observed when combining a MET inhibitor with cisplatin or erlotinib and synergy may be mediated via erbB3/AKT signaling. MET is functionally important in HNSCC with prominent overexpression, increased gene copy number, and mutations. MET inhibition abrogated MET functions, including proliferation, migration/motility, and angiogenesis. MET is a promising, novel target for HNSCC and combination approaches with cisplatin or EGFR inhibitors should be explored. [Cancer Res 2009;69(7):3021–31]

The mammalian target of rapamycin (mTOR) is thought to play a critical role in regulating cell growth, cell cycle progression, and tumorigenesis. Because the AKT-mTOR pathway is frequently hyperactivated in ovarian cancer, we hypothesized that the mTOR inhibitor RAD001 (Everolimus) would inhibit ovarian tumorigenesis in transgenic mice that spontaneously develop ovarian carcinomas. We used TgMISIIR-TAg transgenic mice, which develop bilateral ovarian serous adenocarcinomas accompanied by ascites and peritoneal dissemination. Fifty-eight female TgMISIIR-TAg mice were treated with 5 mg/kg RAD001 or placebo twice weekly from 5 to 20 weeks of age. To monitor tumor development, mice were examined biweekly using magnetic resonance microimaging. In vivo effects of RAD001 on Akt-mTOR signaling, tumor cell proliferation, and blood vessel area were analyzed by immunohistochemistry and Western blot analysis. RAD001 treatment markedly delayed tumor development. Tumor burden was reduced by ∼84%. In addition, ascites formation, together with peritoneal dissemination, was detected in only 21% of RAD001-treated mice compared with 74% in placebo-treated animals. Approximately 30% of RAD001-treated mice developed early ovarian carcinoma confined within the ovary, whereas all placebo-treated mice developed advanced ovarian carcinoma. Treatment with RAD001 diminished the expression of vascular endothelial growth factor in tumor-derived cell lines and inhibited angiogenesis in vivo. RAD001 also attenuated the expression of matrix metalloproteinase-2 and inhibited the invasiveness of tumor-derived cells. Taken together, these preclinical findings suggest that mTOR inhibition, alone or in combination with other molecularly targeted drugs, could represent a promising chemopreventive strategy in women at high familial risk of ovarian cancer. [Cancer Res 2007;67(6):2408–13]

Supplementary Table 1 from The MET Receptor Tyrosine Kinase Is a Potential Novel Therapeutic Target for Head and Neck Squamous Cell Carcinoma

Supplementary Table 1-3 from Characterization of a Carcinogenesis Rat Model of Ovarian Preneoplasia and Neoplasia

Esophageal squamous cell carcinoma (ESCC) is a devastating and common disease worldwide. Despite recent advances annotating the genetic and epigenetic changes underlying the initiation and development of ESCC and its precursor lesion, esophageal squamous dysplasia, more work is needed to translate these findings into novel therapeutic strategies. This gap is due in part to the lack of tractable models of ESCC initiation and development that can then be manipulated ex vivo for preclinical testing. Currently, the large-scale studies characterizing the aforementioned molecular changes have used primary tissue for their analyses and have subsequently been unable to test the specific hypotheses that arise from their data using the original tissue that they profiled. To address this gap, we have generated a large (n = 54) three-dimensional organoid library from the esophagi of mice treated with the carcinogen 4-Nitroquinoline N-oxide (4-NQO) representing each stage of esophageal squamous cell initiation and progression from early intraepithelial dysplasia through lung metastasis. We have determined that these organoids faithfully recapitulate the molecular biology, histology, and oncogenic phenotype of their tissue of origin. Through integrative analysis of both RNA sequencing and whole exome sequencing data, we have identified several novel therapeutic targets that contribute to ESCC initiation and development including the DNA damage response and NOTCH1 signaling. Together, our work capitalizes on the intersection of large-scale multiomics and sophisticated 3D organoid models to identify novel therapeutic targets for the treatment of a devastating disease. Citation Format: Samuel Flashner, Masataka Shimonosono, Satoshi Takada, Norihiro Matsuura, Yasuto Tomita, Xiao Chen, Alison Taylor, Andres Klein-Szanto, Fatameh Momen-Heravi, J. Alan Diehl, Chao Lu, Hiroshi Nakagawa. Leveraging a 3D organoid library to identify novel therapeutic targets during ESCC initiation and progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3077.

Head and neck squamous cell carcinoma (HNSC) is a devastating disease accounting for 570,000 newly diagnosed cases and resulting in 344,000 deaths annually. HNSC arises from its histological precursor lesion, squamous dysplasia (HNSD); however, most patients are diagnosed with late-stage HNSC with no prior identification of pre-malignant disease. Earlier diagnosis and intervention could ameliorate the outsized burden of HNSC; therefore, there is an urgent unmet need to characterize the molecular changes underlying progression through HNSD to HNSC. To identify novel therapeutic targets or biomarkers that predict progression to HNSC, we have generated a three dimensional (3D) organoid library derived from dysplastic oral tissue harvested from mice treated with 4-Nitriquinoline N-oxide (4-NQO), a potent mimetic of tobacco smoke. Through RNA sequencing analysis of these organoids, we have identified two distinct gene expression states that accompany either early or late dysplasia. By performing gene set enrichment analysis of these two distinct gene signatures, we have identified c-Jun N-terminal Kinase (JNK) signaling as a potential biomarker that predicts or progression from HNSD to HNSC. Together, we have identified the salient transcriptional changes that accompany progression through the histological precursor lesion of HNSC. This study positions JNK signaling as a potential biomarker or therapeutic target for early intervention during the treatment of a deadly disease. Citation Format: Robert Agee, Samuel Flashner, Masataka Shimonosono, Andres Klein-Szanto, Hiroshi Nakagawa. Leveraging 3D organoids to identify molecular changes underlying HNSC initiation and development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3082.

Cyclin c is a component of the Cdk8 kinase module that plays both a positive and negative role in transcription. In addition, cellular damage induces cyclin c re-localization to the mitochondria where it stimulates fission and recruits Bax in preparation for apoptotic initiation. Previous studies revealed that cyclin c suppresses thyroid hyperplasia in a Pten knockout mouse model. In the present study, a role for cyclin c in suppressing pancreatic cancer progression was investigated in the Pdx1-Cre LSL-KrasG12D murine pancreatic cancer model. Within eight weeks, a 6-8 fold increase in the appearance of pancreatic intraepithelial neoplasia (PanIN) and acinar ductal metaplasia (ADM) lesions was observed in the KrasG12D+Ccnc-/- animals compared to KrasG12D alone. Surprisingly, high-grade neuroendocrine neoplasms (NEN) were also observed. These aggressive NEN showed mixed morphology with areas of acinar-like differentiation. High grade NEN exhibited pronounced proliferative index (Ki67), high EZH2 expression, and elevated Notch1, suggesting a connection between aberrant Notch signaling and NEN formation. Our previous studies identified a positive role for cyclin c in autophagy gene transcription. Similarly, cell lines derived from a KrasG12D+Ccnc-/- pancreas exhibited a reduction in autophagy compared to KrasG12D+Ccnc+/+ cells. Autophagic deficiency induces pancreatic cell stress and is associated with apoptosis. Consistent with this model, high caspase 3 expression was observed in early KrasG12D+Ccnc-/- NEN but not in KrasG12D+Ccnc+/+ tissues. Taken together, these results demonstrate a role for cyclin c in suppressing both progression of early PanIN and the development of high-grade NEN and suggest a model that cyclin c loss suppresses autophagy and increases apoptosis. Acknowledgements: Support was provided by NCI CCSG grant CA06927 for the FCCC Histopathology and Cell Culture Facilities, the PA Department of Health CURE fund (KSC), the Boye Foundation (RS), and the New Jersey Health Foundation (RS). Citation Format: Kathy Q. Cai, Sara E. Hanley, Andres Klein-Szanto, Kerry S. Campbell, Randy Strich. Cyclin c suppresses pancreatic intraepithelial neoplasm progression and neuroendocrine neoplasm development in a murine Kras model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 816.

Reduced mitochondrial DNA copy number, mitochondrial DNA mutations or disruption of electron transfer chain complexes induce mitochondria-to-nucleus retrograde signaling, which induces global change in nuclear gene expression ultimately contributing to various human pathologies including cancer. Recent studies suggest that these mitochondrial changes cause transcriptional reprogramming of nuclear genes although the mechanism of this cross talk remains unclear. Here, we provide evidence that mitochondria-to-nucleus retrograde signaling regulates chromatin acetylation and alters nuclear gene expression through the heterogeneous ribonucleoprotein A2 (hnRNAP2). These processes are reversed when mitochondrial DNA content is restored to near normal cell levels. We show that the mitochondrial stress-induced transcription coactivator hnRNAP2 acetylates Lys 8 of H4 through an intrinsic histone lysine acetyltransferase (KAT) activity with Arg 48 and Arg 50 of hnRNAP2 being essential for acetyl-CoA binding and acetyltransferase activity. H4K8 acetylation at the mitochondrial stress-responsive promoters by hnRNAP2 is essential for transcriptional activation. We found that the previously described mitochondria-to-nucleus retrograde signaling-mediated transformation of C2C12 cells caused an increased expression of genes involved in various oncogenic processes, which is retarded in hnRNAP2 silenced or hnRNAP2 KAT mutant cells. Taken together, these data show that altered gene expression by mitochondria-to-nucleus retrograde signaling involves a novel hnRNAP2-dependent epigenetic mechanism that may have a role in cancer and other pathologies.

BACKGROUND The goal of the prospective study was to determine whether 1) image analysis (IA; including DNA index [DI], S-phase fraction, and the presence or absence of aneuploidy or hypertetraploidy [HT]) of fiberoptic ductoscopy (FD) breast specimens was feasible, 2) IA findings from FD specimens predicted histopathologic evidence of disease, and 3) a combination of IA, cytology, and clinical factors provided complementary information in the diagnosis of breast carcinoma. METHODS IA and cytologic evaluation were performed on 106 consecutively collected ductoscopic specimens from 88 subjects. RESULTS IA was successful in 73 (71%) FD specimens. HT (P = 0.03) was related to intraductal visual observations. The proportion of atypical papillomas with aneuploidy was greater (P = 0.05) than in any other class. The HT index was higher in atypical papilloma (P = 0.02) and in breast carcinoma (P = 0.05) than with other diagnoses. The proportion of papilloma cases with HT was greater (P = 0.04) than benign papillomas. Malignant cytology was associated with a higher DI (P = 0.02) and a higher HT index (P = 0.001) than nonmalignant (benign or atypical) cytology. HT (P = 0.002) was less common with cytology containing few epithelial cells, and the HT index was higher with malignant versus nonmalignant FD cytology (P = 0.001). The percentage of cells containing HT was greater in FD specimens that were suspicious for malignancy (P = 0.006) than in those with benign cytology or mild atypia. Considering all samples and combining IA, cytologic, and visual findings in a stepwise linear discriminant analysis optimized the sensitivity (61%) and specificity (90%) of breast carcinoma prediction. Excluding spontaneous nipple discharge (SND) samples and adding epithelial cell quantity in samples improved the model (sensitivity, 85%; specificity, 80%). CONCLUSIONS IA was feasible in FD specimens whenever adequate epithelial cells were present. IA and cytologic findings were associated. Adding IA results to cytology and visual findings and excluding samples with SND improved diagnostic sensitivity. Cancer 2004. © 2004 American Cancer Society.

We prospectively performed cytologic assessment and image analysis (IA) on matched nipple aspirate fluid (NAF) and mammary ductoscopy (MD) specimens to determine (1) the accuracy of these methods in cancer detection and (2) whether the two collection methods provide complementary information.NAF and MD specimens were collected from 84 breasts from 75 women (nine bilateral samples) who underwent breast surgery. Cytologic evaluation was performed on all samples. IA was performed on slides with sufficient epithelial cells.Cytologic evaluation proved more accurate in patients without pathologic spontaneous nipple discharge (PND) than those with PND, mainly because of the potential false positive diagnosis in the latter. While the sensitivity of NAF and MD cytology was low (10% and 14%, respectively), both were 100% specific in cancer detection in the non-PND cohort. Combining NAF and MD cytology information improved sensitivity (24%) without sacrificing specificity. Similar to cytology, IA was more accurate in patients without PND having high specificity (100% for aneuploid IA), but relatively low sensitivity (36%). Combining NAF and MD cytology with aneuploid IA improved the sensitivity (45%) while maintaining high specificity (100%). The best predictive model was positive NAF cytology and/or MD cytology combined with IA aneuploidy, which resulted in 55% sensitivity and 100% specificity in breast cancer detection.Cytologic evaluation and IA of NAF and MD specimens are complementary. The presence of atypical cells arising from an intraductal papilloma in ductoscopic specimens is a potential source of false positive diagnosis in patients with nipple discharge.

Nucleoside-based analogues are mainstays in the treatment of cancer, viral infections, and inflammatory diseases. Recent studies showing that the ATP-binding cassette transporter, multidrug resistance protein 4, is able to efflux nucleoside and nucleotide analogues from transfected cells suggests that the pump may affect the efficacy of this class of agents. However, the in vivo pharmacologic functions of the pump are largely unexplored. Here, using Mrp4−/− mice as a model system, and the nucleotide analogue, 9′-(2′-phosphonylmethoxyethyl)-adenine (PMEA) as a probe, we investigate the ability of Mrp4 to function in vivo as an endogenous resistance factor. In the absence of alterations in plasma PMEA levels, Mrp4-null mice treated with PMEA exhibit increased lethality associated with marked toxicity in several tissues. Affected tissues include the bone marrow, spleen, thymus, and gastrointestinal tract. In addition, PMEA penetration into the brain is increased in Mrp4−/− mice. These findings indicate that Mrp4 is an endogenous resistance factor, and that the pump may be a component of the blood-brain barrier for nucleoside-based analogues. This is the first demonstration that an ATP-binding cassette transporter can affect in vivo tissue sensitivity towards this class of agents. [Cancer Res 2007;67(1):262–8]

Poly(ADP-ribose) polymerase 1 (PARP-1) is a nuclear zinc finger DNA-binding protein that is implicated in the repair of DNA damage. Inhibition of PARP-1 through genetic knockouts causes cells to become hypersensitive to various chemotherapeutic agents. We tested the chemopotentiating ability of the PARP-1 inhibitor, CEP-6800, when used in combination with temozolomide (TMZ), irinotecan (camptothecin or SN38), and cisplatin against U251MG glioblastoma, HT29 colon carcinoma, and Calu-6 non-small cell lung carcinoma xenografts and cell lines, respectively. Exposure of tumor cells to TMZ, camptothecin (or SN38), and cisplatin before, or in the presence of, CEP-6800 significantly increased the onset and the magnitude of DNA damage, the duration for cells to effect repair, and the onset, duration, or fraction of cells arrested at the G(2)/M boundary. In addition, in vivo biochemical efficacy studies with CEP-6800 showed that it was able to attenuate irinotecan- and TMZ-induced poly(ADP-ribose) accumulation in LoVo and HT29 xenografts, respectively. Treatment of CEP 6800 (30 mg/kg) with TMZ (17 and 34 mg/kg) resulted in 100% complete regression of U251MG tumors by day 28 versus 60% complete regression caused by TMZ alone. CEP-6800 (30 mg/kg) in combination with irinotecan (10 mg/kg) resulted in a 60% inhibition of HT29 tumor growth versus irinotecan alone by day 33. The combination therapy of cisplatin (5 mg/kg) with CEP-6800 (30 mg/kg) caused a 35% reduction in Calu-6 tumor growth versus cisplatin alone by day 28. These data suggest that CEP-6800 could be used as a chemopotentiating agent with a variety of clinically effective chemotherapeutic agents.