TEMOZOLOMIDE AND BEVACIZUMAB THERAPY IN ADVANCED HEMANGIOPERICYTOMA/ SOLITARY FIBROUS TUMOR

Tumors comprising the spectrum of hemangiopericytoma/ malignant solitary fibrous tumor (HPC/SFT) are thought to arise from fibroblasts and represent a small subset of soft tissue sarcomas. Surgery is typically the treatment of choice for localized disease, with reported 10-year overall survival rates of 54-89% after complete surgical resection. However, for the approximately 20% of HPC/SFT patients who eventually develop local recurrences and/or distant metastases, options for effective treatment are limited and are poorly defined. Alternative therapeutic options are therefore needed for improved palliation and disease control. We hypothesize that HPC/SFT are a spectrum of soft tissue tumors with unique clinical, pathological, and molecular makeup and clinical behavior. HPC/SFT respond to unique therapeutic agents that specifically target aberrations specific to these tumors. We retrospectively reviewed the characteristics and the clinical outcomes for all HPC/SFT patients whose tumor specimens have been reviewed at the MD Anderson Cancer Center from January 1993 to June 2007 by a MD Anderson pathologist and were treated at the institution with available electronic medical records. We identified 128 patients, 79 with primary localized disease and 49 with recurrent and/or metastatic disease. For the 23 patients with advanced HPC/SFT who received adriamycin-based, gemcitabine based, or paclitaxel chemotherapy as first- or second-line therapy, the overall RECIST response rate was 0%. Most patients achieved a brief duration of disease stabilization on chemotherapy, with median progression-free survival (PFS) period of 4.6 months. For the 14 patients with advanced HPC/SFT who received temozolomide and bevacizumab systemic therapy, the overall RECIST response rate was 14%, with the overall Choi response rate of 79%. The median PFS for the cohort was 9.7 months with a median 6-month progression free rate of 78.6%. The most frequently observed toxic effect of temzolomide-bevacizumab therapy was myelosuppression. We have designed a phase II study to evaluate the safety and efficacy of temozolomide-bevaciumab in locally advanced, recurrent, and metastatic HPC/SFT in a prospective manner. Combination therapy with temozolomide and bevacizumab may be a potentially clinically beneficial regimen for advanced HPC/SFT patients.

Uptake And Metabolism Of 5’-AMP In The Erythrocyte Play Key Roles In The 5’-AMP Induced Model Of Deep Hypometabolism

UPTAKE AND METABOLISM OF 5’-AMP IN THE ERYTHROCYTE PLAY KEY ROLES IN THE 5’-AMP INDUCED MODEL OF DEEP HYPOMETABOLISM Publication No. ________ Isadora Susan Daniels, B.A. Supervisory Professor: Cheng Chi Lee, Ph.D. Mechanisms that initiate and control the natural hypometabolic states of mammals are poorly understood. The laboratory developed a model of deep hypometabolism (DH) initiated by uptake of 5’-adenosine monophosphate (5’-AMP) into erythrocytes. Mice enter DH when given a high dose of 5’-AMP and the body cools readily. Influx of 5’-AMP appears to inhibit thermoregulatory control. In a 15°C environment, mice injected with 5’-AMP (0.5 mg/gw) enter a Phase I response in which oxygen consumption (VO2) drops rapidly to 1/3rd of euthermic levels. The Phase I response appears independent of body temperature (Tb). This is followed by gradual body temperature decline that correlates with VO2 decline, called Phase II response. Within 90 minutes, mouse Tb approaches 15°C, and VO2 is 1/10th of normal. Mice can remain several hours in this state, before gradually and safely recovering. The DH state translates to other mammalian species. Our studies show uptake and metabolism of 5’-AMP in erythrocytes causes biochemical changes that initiate DH. Increased AMP shifts the adenylate equilibrium toward ADP formation, consequently decreasing intracellular ATP. In turn, glycolysis slows, indicated by increased glucose and decreased lactate. 2,3-bisphosphoglycerate levels rise, allosterically reducing oxygen affinity for hemoglobin, and deoxyhemoglobin rises. Less oxygen transport to tissues likely triggers the DH model. The major intracellular pathway for AMP catabolism is catalyzed by AMP deaminase (AMPD). Multiple AMPD isozymes are expressed in various tissues, but erythrocytes only have AMPD3. Mice lacking AMPD3 were created to study control of the DH model, specifically in erythrocytes. Telemetric measurements demonstrate lower Tb and difficulty maintaining Tb under moderate metabolic stress. A more dramatic response to lower dose of 5’-AMP suggests AMPD activity in the erythrocyte plays an important role in control of the DH model. Analysis of adenylates in erythrocyte lysate shows 3-fold higher levels of ATP and ADP but similar AMP levels to wild-type. Taken together, results indicate alterations in energy status of erythrocytes can induce a hypometabolic state. AMPD3 control of AMP catabolism is important in controlling the DH model. Genetically reducing AMP catabolism in erythrocytes causes a phenotype of lower Tb and compromised ability to maintain temperature homeostasis.

A quality of life subscale for terminally ill cancer patients

A subscale was developed to assess the quality of life of cancer patients with a life expectancy of six months or less. Phase I of this study identified the major concerns of 74 terminally ill cancer patients (19 with breast cancer, 19 with lung cancer, 18 with colorectal cancer, 9 with renal cell cancer, 9 with prostate cancer), 39 family caregivers, and 20 health care professionals. Patients interviewed were being treated at the University of Texas M. D. Anderson Cancer Center or at the Hospice at the Texas Medical Center in Houston. In Phase II, 120 patients (30 with breast cancer, 30 with lung cancer, 30 with colorectal cancer, 15 with prostate cancer, and 15 with renal cell cancer) rated the importance of these concerns for quality of life. Items retained for the subscale were rated as "extremely important" or "very important" by at least 60% of the sample and were reported as being applicable by at least two-thirds of the sample. The 61 concerns that were identified were formatted as a questionnaire for Phase III. In Phase III, 356 patients (89 with breast cancer, 88 with lung cancer, 88 with colorectal cancer, 44 with prostate cancer, and 47 with renal cell cancer) were interviewed to determine the subscale's reliability and sensitivity to change in clinical status. Both factor analysis and item response theory supported the inclusion of the same 35 items for the subscale. Internal consistency reliability was moderate to high for the subscale's domains: spiritual (0.87), existential (0.76), medical care (0.68), symptoms (0.67), social/family (0.66), and emotional (0.61). Test-retest correlation coefficients also were high for the domains: social/family (0.86), emotional (0.83), medical care (0.83), spiritual (0.75), existential (0.75), and symptoms (0.81).^ In addition, concurrent validity was supported by the high correlation between the subscale's symptom domain and symptom items from the European Organization for Research and Treatment of Cancer (EORTC) scale (r = 0.74). Patients' functional status was assessed with the Eastern Cooperative Oncology Group (ECOG) Performance status rating. When ECOG categories were compared to subscale domains, patients who scored lower in functional status had lower scores in the spiritual, existential, social/family, and emotional domains. Patients who scored lower in physical well-being had higher scores in the symptom domain. Patient scores in the medical care domain were similar for each ECOG category. The results of this study support the subscale's use in assessing quality of life and the outcomes of palliative treatment for cancer patients in their last six months of life. ^

IV thrombolysis and renal function

OBJECTIVE To investigate the association of renal impairment on functional outcome and complications in stroke patients treated with IV thrombolysis (IVT). METHODS In this observational study, we compared the estimated glomerular filtration rate (GFR) with poor 3-month outcome (modified Rankin Scale scores 3-6), death, and symptomatic intracranial hemorrhage (sICH) based on the criteria of the European Cooperative Acute Stroke Study II trial. Unadjusted and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Patients without IVT treatment served as a comparison group. RESULTS Among 4,780 IVT-treated patients, 1,217 (25.5%) had a low GFR (<60 mL/min/1.73 m(2)). A GFR decrease by 10 mL/min/1.73 m(2) increased the risk of poor outcome (OR [95% CI]): (ORunadjusted 1.20 [1.17-1.24]; ORadjusted 1.05 [1.01-1.09]), death (ORunadjusted 1.33 [1.28-1.38]; ORadjusted 1.18 [1.11-1.249]), and sICH (ORunadjusted 1.15 [1.01-1.22]; ORadjusted 1.11 [1.04-1.20]). Low GFR was independently associated with poor 3-month outcome (ORadjusted 1.32 [1.10-1.58]), death (ORadjusted 1.73 [1.39-2.14]), and sICH (ORadjusted 1.64 [1.21-2.23]) compared with normal GFR (60-120 mL/min/1.73 m(2)). Low GFR (ORadjusted 1.64 [1.21-2.23]) and stroke severity (ORadjusted 1.05 [1.03-1.07]) independently determined sICH. Compared with patients who did not receive IVT, treatment with IVT in patients with low GFR was associated with poor outcome (ORadjusted 1.79 [1.41-2.25]), and with favorable outcome in those with normal GFR (ORadjusted 0.77 [0.63-0.94]). CONCLUSION Renal function significantly modified outcome and complication rates in IVT-treated stroke patients. Lower GFR might be a better risk indicator for sICH than age. A decrease of GFR by 10 mL/min/1.73 m(2) seems to have a similar impact on the risk of death or sICH as a 1-point-higher NIH Stroke Scale score measuring stroke severity.

Intrapartum detection of Group B streptococci colonization by rapid PCR-test on labor ward

OBJECTIVE Group B streptococci (GBS) may lead to early onset neonatal sepsis with severe morbidity and mortality of newborns. Intrapartum detection of GBS is needed. The objective was to compare a PCR-based test performed in the laboratory versus labor ward. STUDY DESIGN 300 patients were included prospectively. In phase I, swabs were analyzed by selective culture and rapid PCR in the laboratory. In phase II, swabs were analyzed accordingly, but the PCR test was conducted in labor ward. Test performances were analyzed and compared. RESULTS In phase I the rapid PCR test had a sensitivity of 85.71% and a specificity of 95.9%. The GBS colonization rate was 18.67%. Overall 8.5% of the PCR results were invalid. In phase II the PCR test showed a sensitivity of 85.71% and a specificity of 95.65%. The GBS colonization rate was 23.3%. Overall 23.5% of swabs tested with PCR were invalid. Initiation of specific, short 2-hour training for operating personnel in the labor ward reduced the invalid test rate to 13.4%. CONCLUSION The rapid PCR-based test yields adequate results to identify GBS colonization when performed in labor ward. In order to reduce the number of invalid tests a short training period is needed.

Latrepirdine stimulates autophagy and reduces accumulation of α-synuclein in cells and in mouse brain

Latrepirdine (Dimebon; dimebolin) is a neuroactive compound that was associated with enhanced cognition, neuroprotection and neurogenesis in laboratory animals, and has entered phase II clinical trials for both Alzheimer's disease and Huntington's disease (HD). Based on recent indications that latrepirdine protects cells against cytotoxicity associated with expression of aggregatable neurodegeneration-related proteins, including Aβ42 and γ-synuclein, we sought to determine whether latrepirdine offers protection to Saccharomyces cerevisiae. We utilized separate and parallel expression in yeast of several neurodegeneration-related proteins, including α-synuclein (α-syn), the amyotrophic lateral sclerosis-associated genes TDP43 and FUS, and the HD-associated protein huntingtin with a 103 copy-polyglutamine expansion (HTT gene; htt-103Q). Latrepirdine effects on α-syn clearance and toxicity were also measured following treatment of SH-SY5Y cells or chronic treatment of wild-type mice. Latrepirdine only protected yeast against the cytotoxicity associated with α-syn, and this appeared to occur via induction of autophagy. We further report that latrepirdine stimulated the degradation of α-syn in differentiated SH-SY5Y neurons, and in mouse brain following chronic administration, in parallel with elevation of the levels of markers of autophagic activity. Ongoing experiments will determine the utility of latrepirdine to abrogate α-syn accumulation in transgenic mouse models of α-syn neuropathology. We propose that latrepirdine may represent a novel scaffold for discovery of robust pro-autophagic/anti-neurodegeneration compounds, which might yield clinical benefit for synucleinopathies including Parkinson's disease, Lewy body dementia, rapid eye movement (REM) sleep disorder and/or multiple system atrophy, following optimization of its pro-autophagic and pro-neurogenic activities.

Immunologic response to the survivin-derived multi-epitope vaccine EMD640744 in patients with advanced solid tumors

PURPOSE Survivin is a member of the inhibitor-of-apoptosis family. Essential for tumor cell survival and overexpressed in most cancers, survivin is a promising target for anti-cancer immunotherapy. Immunogenicity has been demonstrated in multiple cancers. Nonetheless, few clinical trials have demonstrated survivin-vaccine-induced immune responses. EXPERIMENTAL DESIGN This phase I trial was conducted to test whether vaccine EMD640744, a cocktail of five HLA class I-binding survivin peptides in Montanide(®) ISA 51 VG, promotes anti-survivin T-cell responses in patients with solid cancers. The primary objective was to compare immunologic efficacy of EMD640744 at doses of 30, 100, and 300 μg. Secondary objectives included safety, tolerability, and clinical efficacy. RESULTS In total, 49 patients who received ≥2 EMD640744 injections with available baseline- and ≥1 post-vaccination samples [immunologic-diagnostic (ID)-intention-to-treat] were analyzed by ELISpot- and peptide/MHC-multimer staining, revealing vaccine-activated peptide-specific T-cell responses in 31 patients (63 %). This cohort included the per study protocol relevant ID population for the primary objective, i.e., T-cell responses by ELISpot in 17 weeks following first vaccination, as well as subjects who discontinued the study before week 17 but showed responses to the treatment. No dose-dependent effects were observed. In the majority of patients (61 %), anti-survivin responses were detected only after vaccination, providing evidence for de novo induction. Best overall tumor response was stable disease (28 %). EMD640744 was well tolerated; local injection-site reactions constituted the most frequent adverse event. CONCLUSIONS Vaccination with EMD640744 elicited T-cell responses against survivin peptides in the majority of patients, demonstrating the immunologic efficacy of EMD640744.

Cilengitide treatment of newly diagnosed glioblastoma patients does not alter patterns of progression

The integrin antagonist cilengitide has been explored as an adjunct with anti-angiogenic properties to standard of care temozolomide chemoradiotherapy (TMZ/RT → TMZ) in newly diagnosed glioblastoma. Preclinical data as well as anecdotal clinical observations indicate that anti-angiogenic treatment may result in altered patterns of tumor progression. Using a standardized approach, we analyzed patterns of progression on MRI in 21 patients enrolled onto a phase 2 trial of cilengitide added to TMZ/RT → TMZ in newly diagnosed glioblastoma. Thirty patients from the experimental treatment arm of the EORTC/NCIC pivotal TMZ trial served as a reference. MRIcro software was used to map location and extent of initial preoperative and recurrent tumors on MRI of both groups into the same stereotaxic space which were then analyzed using an automated tool of image analysis. Clinical and outcome data of the cilengitide-treated patients were similar to those of the EORTC/NCIC trial except for a higher proportion of patients with a methylated O(6)-methylguanyl-DNA-methyltransferase gene promoter. Analysis of recurrence pattern revealed neither a difference in the size of the recurrent tumor nor in the distance of the recurrences from the preoperative tumor location between groups. Overall frequencies of distant recurrences were 20 % in the reference group and 19 % (4/21 patients) in the cilengitide group. Compared with TMZ/RT → TMZ alone, the addition of cilengitide does not alter patterns of progression. This analysis does not support concerns that integrin antagonism by cilengitide may induce a more aggressive phenotype at progression, but also provides no evidence for an anti-invasive activity of cilengitide in patients with newly diagnosed glioblastoma.

Metabolic profiling of praziquantel enantiomers

Praziquantel (PZQ), prescribed as a racemic mixture, is the most readily available drug to treat schistosomiasis. In the present study, ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOFMS) based metabolomics was employed to decipher the metabolic pathways and enantioselective metabolic differences of PZQ. Many phase I and four new phase II metabolites were found in urine and feces samples of mice 24h after dosing, indicating that the major metabolic reactions encompassed oxidation, dehydrogenation, and glucuronidation. Differences in the formation of all these metabolites were observed between (R)-PZQ and (S)-PZQ. In an in vitro phase I incubation system, the major involvement of CYP3A, CYP2C9, and CYP2C19 in the metabolism of PZQ, and CYP3A, CYP2C9, and CYP2C19 exhibited different catalytic activity toward the PZQ enantiomers. Apparent Km and Vmax differences were observed in the catalytic formation of three mono-oxidized metabolites by CYP2C9 and CYP3A4 further supporting the metabolic differences for PZQ enantiomers. Molecular docking showed that chirality resulted in differences in substrate location and conformation, which likely accounts for the metabolic differences. In conclusion, in silico, in vitro, and in vivo methods revealed the enantioselective metabolic profile of praziquantel.

Linking Ah receptor mediated effects of sediments and impacts on fish to key pollutants in the Yangtze Three Gorges Reservoir, China – A comprehensive perspective

The Three Gorges Reservoir (TGR), created in consequence of the Yangtze River's impoundment by the Three Gorges Dam, faces numerous anthropogenic impacts that challenge its unique ecosystem. Organic pollutants, particularly aryl hydrocarbon receptor (AhR) agonists, have been widely detected in the Yangtze River, but only little research was yet done on AhR-mediated activities. Hence, in order to assess effects of organic pollution, with particular focus on AhR-mediated activities, several sites in the TGR area were examined applying the "triad approach". It combines chemical analysis, in vitro, in vivo and in situ investigations to a holistic assessment. Sediments and the benthic fish species Pelteobagrus vachellii were sampled in 2011/2012, respectively, to identify relevant endpoints. Sediment was tested in vitro with the ethoxyresorufin-O-deethylase (EROD) induction assay, and in vivo with the Fish Embryo Toxicity Test and Sediment Contact Assay with Danio rerio. Activities of phase I (EROD) and phase II (glutathione-S-transferase) biotransformation enzymes, pollutant metabolites and histopathological alterations were studied in situ in P. vachellii. EROD induction was tested in vitro and in situ to evaluate possible relationships. Two sites, near Chongqing and Kaixian city, were identified as regional hot-spots and further investigated in 2013. The sediments induced in the in vitro/in vivo bioassays AhR-mediated activities and embryotoxic/teratogenic effects - particularly on the cardiovascular system. These endpoints could be significantly correlated to each other and respective chemical data. However, particle-bound pollutants showed only low bioavailability. The in situ investigations suggested a rather poor condition of P. vachellii, with histopathological alterations in liver and excretory kidney. Fish from Chongqing city exhibited significant hepatic EROD induction and obvious parasitic infestations. The polycyclic aromatic hydrocarbon (PAH) metabolite 1-hydroxypyrene was detected in bile of fish from all sites. All endpoints in combination with the chemical data suggest a pivotal role of PAHs in the observed ecotoxicological impacts.

Performance of gene-expression profiling test score variability to predict future clinical events in heart transplant recipients.

BACKGROUND A single non-invasive gene expression profiling (GEP) test (AlloMap®) is often used to discriminate if a heart transplant recipient is at a low risk of acute cellular rejection at time of testing. In a randomized trial, use of the test (a GEP score from 0-40) has been shown to be non-inferior to a routine endomyocardial biopsy for surveillance after heart transplantation in selected low-risk patients with respect to clinical outcomes. Recently, it was suggested that the within-patient variability of consecutive GEP scores may be used to independently predict future clinical events; however, future studies were recommended. Here we performed an analysis of an independent patient population to determine the prognostic utility of within-patient variability of GEP scores in predicting future clinical events. METHODS We defined the GEP score variability as the standard deviation of four GEP scores collected ≥315 days post-transplantation. Of the 737 patients from the Cardiac Allograft Rejection Gene Expression Observational (CARGO) II trial, 36 were assigned to the composite event group (death, re-transplantation or graft failure ≥315 days post-transplantation and within 3 years of the final GEP test) and 55 were assigned to the control group (non-event patients). In this case-controlled study, the performance of GEP score variability to predict future events was evaluated by the area under the receiver operator characteristics curve (AUC ROC). The negative predictive values (NPV) and positive predictive values (PPV) including 95 % confidence intervals (CI) of GEP score variability were calculated. RESULTS The estimated prevalence of events was 17 %. Events occurred at a median of 391 (inter-quartile range 376) days after the final GEP test. The GEP variability AUC ROC for the prediction of a composite event was 0.72 (95 % CI 0.6-0.8). The NPV for GEP score variability of 0.6 was 97 % (95 % CI 91.4-100.0); the PPV for GEP score variability of 1.5 was 35.4 % (95 % CI 13.5-75.8). CONCLUSION In heart transplant recipients, a GEP score variability may be used to predict the probability that a composite event will occur within 3 years after the last GEP score. TRIAL REGISTRATION Clinicaltrials.gov identifier NCT00761787.

Effectiveness of Fluorescence-based Methods in Monitoring Progression of Noncavitated Caries-like Lesions on Smooth Surfaces

Although there has been a significant decrease in caries prevalence in developed countries, the slower progression of dental caries requires methods capable of detecting and quantifying lesions at an early stage. The aim of this study was to evaluate the effectiveness of fluorescence-based methods (DIAGNOdent 2095 laser fluorescence device [LF], DIAGNOdent 2190 pen [LFpen], and VistaProof fluorescence camera [FC]) in monitoring the progression of noncavitated caries-like lesions on smooth surfaces. Caries-like lesions were developed in 60 blocks of bovine enamel using a bacterial model of Streptococcus mutans and Lactobacillus acidophilus . Enamel blocks were evaluated by two independent examiners at baseline (phase I), after the first cariogenic challenge (eight days) (phase II), and after the second cariogenic challenge (a further eight days) (phase III) by two independent examiners using the LF, LFpen, and FC. Blocks were submitted to surface microhardness (SMH) and cross-sectional microhardness analyses. The intraclass correlation coefficient for intra- and interexaminer reproducibility ranged from 0.49 (FC) to 0.94 (LF/LFpen). SMH values decreased and fluorescence values increased significantly among the three phases. Higher values for sensitivity, specificity, and area under the receiver operating characteristic curve were observed for FC (phase II) and LFpen (phase III). A significant correlation was found between fluorescence values and SMH in all phases and integrated loss of surface hardness (ΔKHN) in phase III. In conclusion, fluorescence-based methods were effective in monitoring noncavitated caries-like lesions on smooth surfaces, with moderate correlation with SMH, allowing differentiation between sound and demineralized enamel.

Perspective transformation: Women in long-term recovery from alcohol abuse

Objective. The purpose of this study was to determine the meaning of personal transformation for twenty women in long term, stable recovery from alcohol abuse; to identify themes or patterns of this recovery, and; to determine the extent to which they experienced the phenomenon of perspective transformation. ^ Method. Volunteers were recruited by advertisement, word of mouth, and through a closed circuit web based broadcast. A descriptive, exploratory study, which analyzed perspective transformation from the standpoint of five action phases, was conducted. Data was collected using in-depth personal interviews and questionnaires. Subjects' responses were analyzed by qualitative methods. Triangulation was performed on the grouped data comparing the interviews to the data produced by the questionnaires. Quantitative analysis of questionnaire items explored behavioral changes experienced before and after alcoholism recovery. ^ Results. Five phases of recovery were identified. Phase I which involved recognition that alcohol was a problem and change might be possible took several years during which 3 major transitions occurred: (1) from often being alienated to having relationships with family and friends; (2) from daily upheavals to eventually a more peaceful existence, and; (3) from denial that alcohol was a problem to acceptance and willingness to change. Recovery was often seen in a spiritual context, which also required ongoing support. During Phase II there was an assessment of self, others, and the environment which revealed a pattern of intense unhappiness and negative feelings toward self and others with a disregard for cultural norms. Phase III revealed a period of desperation as life became unmanageable, but gradual willingness to accept support and guidance and a desire to improve self and help others. This led to improvement of existing role performance and the willingness to try out new roles. In Phase IV there was a pattern of personal growth which included: the establishment of boundaries, setting priorities, a willingness to place others' needs above their own, acceptance of responsibility, and learning to cope without alcohol, often with the use of tools learned in AA. During Phase V, many experienced knowledge of frailties but growing respect for self and others, with an improved ability to function in giving relationships. Implications for Prevention and Recovery: Early education concerning addiction and recovery may play a crucial role in prevention and early recovery, as it did for children of women in this study. Recovery requires persistent effort and organized support. ^

Molecular mechanisms of apoptosis induction in chronic lymphocytic leukemia

CLL is the most common adult leukemia in the Western World, yet very little is known about the biology of this disease. CLL cells have very high levels of NF-κB activity. Factors such as CD40 ligation and phorbol ester treatment induce NF-κB activity and also prevent apoptosis. Previous data from our laboratory demonstrated that MG-132, a proteasome inhibitor, blocked NF-κB activation and promoted apoptosis in CLL cells. These data suggested to us that NF-κB mediates survival in CLL. We examined NF-κB activity using two different chemotherapeutic agents, PS-341 and arsenic trioxide. PS-341, a proteasome inhibitor blocked NF-κB in CLL cells. This however, did not correlate with cell death. Resistant patient isolates displayed delayed Smac/DIABLO release in comparison to cytochrome c release. This suggests that IAPs are contributing to CLL cell survival and drug-resistance. Arsenic trioxide did not block NF-κB activity at therapeutic doses. However it was a potent inducer of apoptosis in CLL cells. We identified a novel mechanism by which arsenic induces increases in mitochondrial calcium to induce cytochrome c release and initiate apoptosis. Both PS-341 and arsenic trioxide are currently in Phase II clinical trials at M.D. Anderson Cancer Center. We conclude that NF-κB is not critical for PS-341 or arsenic trioxide-mediated cell death. ^

Pharmacogenetics of the human glutathione S-transferase P1 gene in the metabolism and therapeutic efficacy of cis-diamminedichloroplatinum

The human GSTP1 gene has been shown, conclusively, to be polymorphic. The three main GSTP1 alleles, GSTP1*A, GSTP1*B, and GSTP1*C, encode proteins which differ in the 3-dimensional structure of their active sites and in their function in phase II metabolism of carcinogens, mutagens, and anticancer agents. Although, it is well established that GSTP1 is over expressed in many human tumors and that the levels of GSTP1 expression correlate directly with tumor resistance to chemotherapy and inversely with patient survival, the significance of the polymorphic GSTP1 gene locus on tumor response to chemotherapy remains unclear. The goal of this project was to define the role and significance of the polymorphic GSTP1 gene locus in GSTP1-based tumor drug resistance and as a determinant of patient response to chemotherapy. The hypothesis to be tested was that the polymorphic GSTP1 gene locus will confer to tumors a differential ability to metabolize cisplatin resulting in a GSTP1 genotype-based sensitivity to cisplatin. The study examined: (a) whether the different GSTP 1 alleles confer different levels of cellular protection against cisplatin-induced cytotoxicity, (b) whether the allelic GSTP1 proteins metabolize cisplatin with different efficiencies, and (c) whether the GSTP1 genotype is a determinant of tumor response to cisplatin therapy. The results demonstrate that the GSTP1 alleles differentially protect tumors against cisplatin-induced apoptosis and clonogenic cell kill in the rank order: GSTP1*C > GSTP1*B > GSTP1*A. The same rank order was observed for the kinetics of GSTP1-catalyzed cisplatin metabolism, both in cell-free and cellular systems, to the rate-limiting monoglutathionyl-platinum metabolite, which was characterized, for the first time, by mass spectral analysis. Finally, this study demonstrates that both GSTP1 genotype and the level of GSTP1 expression significantly contribute to tumor sensitivity to cisplatin treatment. Overall, the results of this project show that the polymorphic GSTP1 gene locus plays a significant role in tumor sensitivity to cisplatin treatment. Furthermore, these studies have contributed to the overall understanding of the significance of the polymorphic GSTP1 gene locus in tumor resistance to cancer chemotherapy and have provided the basis for further investigations into how this can be utilized to optimize and individualize cancer chemotherapy for cancer patients. ^