Abstract B159: Heterozygous IDH1 mutations modify the citric acid (TCA) cycle metabolism and sensitize cells to inhibition of mitochondrial respiration/oxidative phosphorylation

Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) occur in a variety of tumor types. Although these mutations are loss-of-function for conversion of isocitrate to α-ketoglutarate, the mutant enzymes greatly increase the production of the proposed oncometabolite, 2-hydroxyglutarate (2-HG). However the full metabolic consequences of IDH1/2 mutation in their heterozygous cellular context have yet to be fully explored. To address this question, we utilized a panel of isogenic cell lines with wild-type IDH1/2 or clinically relevant IDH1/2 mutations and examined the metabolic consequences of IDH mutation using (13)C metabolic flux analysis (MFA).

We observe a dramatic and consistent decrease in the ability of IDH1 mutant cell lines to utilize reductive glutamine metabolism via the carboxylation of α-ketoglutarate back to isocitrate. This was not seen either in IDH2 mutant cell lines or in wild-type cell lines treated with exogenous 2-HG. Consistent with these changes, the IDH1 mutant cell lines, but not IDH2 mutant or 2-HG treated cells, were deficient in the utilization of glutamine for de novo lipogenesis. Similar trends were observed in endogenous, non-engineered IDH1/2 mutant cell lines.

The decrease in reductive carboxylation in the IDH1 mutant cell lines raises the hypothesis that these cells may be more reliant on mitochondrial metabolism. Indeed, IDH1 mutant cells were more sensitive to either treatment with an electron transport chain inhibitor or growth in hypoxia (which also inhibits mitochondrial metabolism).

These results show heterozygous IDH1 mutation robustly impacts wild-type cellular metabolism in a different manner than IDH2 mutation. Furthermore, these results suggest that IDH1 and IDH2 mutant tumors may be differentially sensitive to inhibitors of specific metabolic pathways.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B159.

Citation Format: Alexandra R. Grassian, Seth Parker, Shawn Davidson, Courtney Green, Fallon Lin, Carol Joud-Caldwell, Hong Yin, Franklin Chung, Christopher Straub, Matthew Vander Heiden, Raymond Pagliarini, Christian Metallo. Heterozygous IDH1 mutations modify the citric acid (TCA) cycle metabolism and sensitize cells to inhibition of mitochondrial respiration/oxidative phosphorylation. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B159.

Management of raised glucose, a clinical decision tool to reduce length of stay of patients with hyperglycaemia

OBJECTIVE

To assess whether the introduction of a management of raised glucose clinical decision tool could improve assessment of patients with hyperglycaemia by non-specialist physicians, leading to early discharge and improved quality of inpatient care.

METHODS

Participants were adults aged 18 years or over presenting to the Medical Assessment Unit with a capillary blood glucose level > 11.1 mmol/l. Phase 1 of the study (phase 1) evaluated current clinical practice and potential impact of the clinical decision tool. Phase 2 evaluated the effectiveness of the management of raised glucose tool in clinical practice. Primary outcome measures were inpatient length of stay and same-calendar-day discharges. Secondary outcome measures were diabetes specialist input, patient assessment, intravenous insulin infusion use and patient satisfaction.

RESULTS

Implementation of the management of raised glucose clinical decision tool allowed safe, same-calendar-day discharges of 40% of patients with hyperglycaemia as their primary reason for attendance. Median length of stay was lower in the phase 1 than in phase 2 (1.0 vs. 3.5 days, P < 0.01). Early discharge did not result in an increase in readmissions. There was improvement in hyperglycaemia assessment for all patients (P < 0.01), a reduction in the use of intravenous insulin infusions (P < 0.01) and high level of patient satisfaction.

CONCLUSION

The management of raised glucose clinical decision tool resulted in a significant increase in the number of same-calendar-day discharges and reduction in hospital length of stay without adverse impact on readmission rates. Additionally, the tool was associated with improvements in inpatient diabetes care and patient satisfaction.

A comparison of 4 methods for assessing tumor vascularity in carcinoma of the cervix

A comparison was made of four methods for assessing tumour vascularity in carcinoma of the cervix. Formalin fixed tumour sections were stained with Masson's trichrome and measurements were made of the percentage of tumour blood vessels, vascular density (i.e. the proportion of blood vessels in the stroma) and inter-capillary distance (ICD). ICD was also obtained on anti-Factor VIII stained sections. The assessment of tumour vascularity was shown to be operator-dependent. For all the methods examined, statistically significant differences were seen between the values obtained by two people independently scoring the same sections. Nevertheless, weak correlations were seen between the different scorers for all the methods with measurements of ICD giving the strongest correlations. Either weak or no correlations were seen between the various methods used for assessing the tumour vasculature. An evaluation was made of the ability of the various methods to predict patient outcome for patients a minimum of two years post treatment with radiotherapy alone. Only measurements of the percentage of tumour blood vessels were shown to correlate with patient outcome. These data highlight the importance of having a single individual obtain measurements of tumour vascularity and suggest that the method chosen to determine vascularity may influence the results obtained.

Epidemiology and clinical significance of non-tuberculous mycobacteria isolated from pulmonary specimens

SETTING

A tertiary university medical centre in northern Israel.

OBJECTIVE

To evaluate the clinical significance of non-tuberculous mycobacteria (NTM) isolated from pulmonary specimens.

DESIGN

Clinical and microbiological data were collected from patient files. Cases were classified as definite, probable and possible NTM.

RESULTS

Between 2004 and 2010, 215 cases with respiratory isolates of NTM were identified. Mycobacterium xenopi was the most common species (n = 84, 39.1%), followed by M. simiae (n = 52, 24.2%). A total of 170 (79.1%) cases were classified as possible and 24 (11.2%) as probable NTM. Only 21 (9.8%) cases were considered definite NTM, the majority of which were M. kansasii and M. avium complex.

CONCLUSIONS

M. xenopi and M. simiae are the most prevalent species of NTM isolated from respiratory samples in northern Israel. However, most of these isolates represent colonisation. Of the relatively small number of clinically significant isolates, M. kansasii and M. avium complex were the most common.

A replicated association between polymorphisms near TNFα and risk for adverse reactions to radiotherapy

BACKGROUND

Response to radiotherapy varies between individuals both in terms of efficacy and adverse reactions. Finding genetic determinants of radiation response would allow the tailoring of the treatment, either by altering the radiation dose or by surgery. Despite a growing number of studies in radiogenomics, there are no well-replicated genetic association results.

METHODS

We carried out a candidate gene association study and replicated the result using three additional large cohorts, a total of 2036 women scored for adverse reactions to radiotherapy for breast cancer.

RESULTS

Genetic variation near the tumour necrosis factor alpha gene is shown to affect several clinical endpoints including breast induration, telangiectasia and overall toxicity. In the combined analysis homozygosity for the rare allele increases overall toxicity (P=0.001) and chance of being in the upper quartile of risk with odds ratio of 2.46 (95% confidence interval 1.52-3.98).

CONCLUSION

We have identified that alleles of the class III major histocompatibility complex region associate with overall radiotherapy toxicity in breast cancer patients by using internal replication through a staged design. This is the first well-replicated report of a genetic predictor for radiotherapy reactions.

SU-E-T-210: Surviving a Visit by the Radiological Physics Center

PURPOSE

To demonstrate an objective approach to determining if a negative report from the Radiological Physics Center (RPC) of greater than 10% error is valid or has clinical significance.

METHODS

The discrepancy involved the clinical activity (mgRaEq) of Cs-137 sources, some manufactured by 3M and some by Amersham. Measurements were made in the proprietary RPC Well Counter calibrated by the MD Anderson ADCL and our Well Counter (CNMC, Model 44D) calibrated by the same laboratory as well as the University of Wisconsin ADCL. In addition, we possess an Amersham Cs-137 Check Source that had been calibrated by the UW-ADCL in 2002. All clinical sources were checked in both Well Counters on the first visit. One clinical source and the Check Source were measured in a second visit that occurred 51 days later.

RESULTS

On the initial RPC visit, 9 of 25 sources had a minimum of an 8% discrepancy between the RPC and the Institution, with a maximum of 11%. Contributing errors included using the incorrect straw position by us, an unexplained 2.3% error in the RPC data identified 73 days post-visit, a 2% variation in Chamber Factors for our Well Counter from the two ADCL's. When we use the 2004 value of Air Kerma Strength for the Check Source to determine a Calibration Factor of the Well Counter, all sources were within 0.5% of their decayed value established in 2002.

CONCLUSIONS

This work emphasizes the value of having simple Constancy Check systems in a Quality Assurance program as 'Accuracy' has error bars. The disagreement in calibration data between the ADCL Laboratories, which was at the 2% maximum quoted in their Calibration Reports, is a reminder that there is uncertainty in measurements. Constancy Checks allow one to sort out discrepancies and to answer challenges to the validity of your program.

SU-E-T-190: Design, Development, and Evaluation of a Modified, Anthropomorphic, Head, Quality Assurance Phantom for Use in Stereotactic Radiosurgery

PURPOSE

To develop and evaluate a modified anthropomorphic head phantom for evaluation of stereotactic radiosurgery (SRS) dose planning and delivery.

METHODS

A phantom was constructed from a water equivalent, plastic, head-shaped shell. The original phantom design, with only a spherical target, was modified to include a nonspherical target (pituitary) and an adjacent organ at risk (OAR) (optic chiasm), within 2 mm, simulating the anatomy encountered when treating acromegaly. The target and OAR spatial proximity provided a more realistic treatment planning and dose delivery exercise. A separate dosimetry insert contained two TLD for absolute dosimetry and radiochromic film, in the sagittal and coronal planes, for relative dosimetry. The prescription was 25Gy to 90% of the GTV with >= 10% of the OAR volume receiving >= 8Gy. The modified phantom was used to test the rigor of the treatment planning process, dosimeter reproducibility, and measured dose delivery agreement with calculated doses using a Gamma Knife, CyberKnife, and linear accelerator based radiosurgery systems.

RESULTS

TLD results from multiple irradiations using either a CyberKnife or Gamma Knife agreed with the calculated target dose to within 4.7% with a maximum coefficient of variation of+/-2.0%. Gamma analysis in the coronal and sagittal film planes showed an average passing rate of 99.3% and 99.5% using +/-5%/3mm criteria, respectively. A treatment plan for linac delivery was developed meeting the prescription guidelines. Dosimeter reproducibility and dose delivery agreement for the linac is expected to have results similar to the results observed with the CyberKnife and Gamma Knife.

CONCLUSIONS

A modified anatomically realistic SRS phantom was developed that provided a realistic clinical planning and delivery challenge that can be used to credential institutions wanting to participate in NCI funded clinical trials. Work supported by PHS CA010953, CA081647, CA21661 awarded by NCI. DHHS.

A quality assurance programme for cell salvage in cardiac surgery

At the same time as cell salvage was introduced into our institution for all patients undergoing cardiac surgery with cardiopulmonary bypass, we established a supporting programme of quality assurance to reassure clinicians regarding safety and efficacy. Data collected in patients operated on between 2001 and 2007 included pre- and post-wash heparin concentration, haemoglobin concentration and free haemoglobin concentration. Cell salvage was used in 6826 out of a total of 7243 patients (94%). Post-wash heparin concentration was consistently low (always < 0.4 IU.ml(-1)). There was a significant decrease in post-wash haemoglobin concentration in 2003 compared to 2001, from a median (IQR [range]) of 19.6 (16.7-22.2 [12.9-25.5]) g.dl(-1) to 17.5 (13.6-20.8 [12.6-23.7]) g.dl(-1) (p < 0.015). In addition, there was a significant increase in free plasma haemoglobin in 2006 compared to 2001, from 0.5 (0.3-0.8 [0.1-2.6]) g.l(-1) to 0.8 (0.3-1.4 [0.3-5.2]) g.l(-1) (p < 0.001). This programme led to the detection of a change in operator behaviour in 2003 and progressive machine deterioration resulting in appropriate fleet replacement in 2006. You can respond to this article at http://www.anaesthesiacorrespondence.com.

Evaluation of a health promotion program for reducing depression, anxiety and stress in community-dwelling older adults

Aim

Health education programs that address risk factors for depression and promote positive mental health are approaches that can improve mental wellbeing. We investigated the effectiveness of a health promotion program for reducing levels of depression, anxiety and stress and for promoting appropriate help-seeking behaviour.

Methods

Fifty-five adults 55+years (43 female, 12 male) self-selected to attend the Healthy & Wise program - a group-based, 8 × 2hr session health-literacy program for promoting positive physical, mental and social functioning in a rural setting. A questionnaire was administered at base-line and post-intervention which included the DASS-21 to measure depression, anxiety and stress levels.

Results

No significant change in depression scores (mean = 3.60pre-3.51post). Anxiety scores increased (mean 2.92pre-3.51post) (p = .036) correlating with age (p = .029) and change in physical health status (p = .002).

Stress scores increased (mean 4.81pre-5.59post) (p = .05) correlating with age (p = .033) and change in physical health status (p = .016).

Most participants (pre = 96.36%, post = 98%) indicated they would be likely to seek help from a GP if depressed. Men who mainly rely on their spouse for support were more likely to seek help from a psychologist or psychiatrist (p = .038).

Conclusions

There was no significant change in DASS-21 scores for depression. There was an increase in anxiety and stress levels which may be attributable to older participants experiencing a decline in physical health during the program. Participants remained firm in their preference for seeking help from their GP for depression. Further evaluation is needed to determine whether: at-risk-populations need to be targeted; the intervention has an impact at 12-month follow-up.

Not just a 'simple stroke'

A 51-year-old man presenting with left arm weakness and slurred speech was referred to the acute medical team. Admission chest X-ray showed a cavitating lesion, which had not been present 2 weeks earlier. Systemic enquiry elicited a 2 month prodromal illness and back pain. Urgent CT of his head and chest revealed evidence of thoracic discitis spreading anteriorly into a pleural-based lung abscess and an intracerebral abscess causing his neurological deficit. He was transferred for urgent craniotomy and evacuation of a Streptococcus milleri abscess. Following several weeks of neurosurgical care and antibiotics he made a near full recovery.

Phase I study of RAD001 (everolimus), cetuximab, and irinotecan as second-line therapy in metastatic colorectal cancer (mCRC)

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Background: The PI3K/AKT/mTOR pathway is frequently dysregulated in colorectal cancer (Cancer Res 2005;65:11227). In a phase I study in patients with advanced solid tumors, everolimus an oral mTOR inhibitor demonstrated clinical benefit including a partial response in pts with colorectal cancer (J Clin Oncol 2008;26:1603–10; J Clin Oncol 2008; 26:1588–95). Methods: This open-label, multicenter phase I study uses a Bayesian logistic model to identify feasible doses of everolimus + irinotecan + cetuximab. Adult pts with mCRC progressing despite prior 5-FU/oxaliplatin (FOLFOX) or capecitabine/oxaliplatin (XELOX) plus bevacizumab (if standard practice) were treated using a sequential dose escalation scheme (Table). Dose decisions were driven by the probability of dose-limiting toxicity (DLT) in the first 2 cycles. Dose level decisions were based on maximizing the probability that end-of-cycle-2 DLT rate would be within the targeted toxicity interval (20% to <35%) and minimizing the risk of over-dosing (< 5% risk of unacceptable toxicity and < 25% risk of excessive/unacceptable toxicity). Results: 18 pts were treated from April ‘07 to August ‘08, 5 pts at dose level A1 and 13 pts at dose level B1. Two DLTs (G3 rash on cycle 2 day 1 lasting > 7 days and G3 mucositis on cycle 1 day 14 lasting > 7 days, 1 pt each) were reported in 4 evaluable pts at dose level A1. No DLTs were reported in 7 evaluable patients at dose level B1. Conclusions: At dose level B1 everolimus in combination with irinotecan and cetuximab was generally well tolerated. The study was stopped due to changes in clinical practice based on emerging data indicating that cetuximab has limited efficacy in mCRC patients with KRAS mutations and that efficacy data favors daily RAD001 over weekly dosing. Patients in this study were treated with cetuximab irrespective of KRAS status.

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Pharmacodynamic resistance to warfarin is associated with nucleotide substitutions in VKORC1

BACKGROUND

Vitamin K epoxide reductase subunit 1 (VKORC1) is the molecular target of coumarin anticoagulants and mutations in VKORC1 have been identified previously in individuals who required high warfarin doses.

OBJECTIVE

Detailed characterization of the relationship between variation in VKORC1 and the warfarin resistance phenotype.

PATIENTS AND METHODS

Serum warfarin concentration and coagulation parameters were determined in 289 subjects who required warfarin doses >20 mg day(-1). The VKORC1 sequence was studied in selected study subjects.

RESULTS

Twenty-eight out of 289 (10%) subjects had serum warfarin >2.3 mg L(-1) during stable therapeutic anticoagulation indicating pharmacodynamic warfarin resistance. Detailed analysis of 15 subjects from this group showed that eight out of 15 (53%) had nucleotide substitutions in VKORC1 predictive of p.V66M, p.L128R, p.V54L or p.D36Y. VKORC1 was normal in the remaining seven out of 15 (47%) subjects and in nine out of nine (100%) subjects with high warfarin dose requirement not caused by pharmacodynamic resistance. At referral, subjects with VKORC1 mutations received a median warfarin dose of 32 mg day(-1) (range 22-55) and had a median serum warfarin concentration of 4.6 mg L(-1) (range 2.6-9.0). VKORC1 substitutions were associated with a requirement for high warfarin doses but not with adverse clinical events. Family members with VKORC1 nucleotide substitutions and not receiving warfarin had undetectable PIVKA-II and K(1) epoxide (K(1)O).

CONCLUSIONS

Nucleotide variations in VKORC1 are a common cause of pharmacodynamic warfarin resistance but are not associated with adverse outcome during anticoagulation. Mutations associated with warfarin resistance do not cause a discernible defect in VKORC1 reductase function.

Assessing the impact of late treatment effects in cervical cancer: an exploratory study of women?s sexuality

Cancer survivorship has become a major issue due to people living longer with the effects of cancer treatment. A key issue in this area are the 'iatrogenic effects' of cancer treatments and their adverse impact on the quality of long-term patient survival. This paper considers the late physical effects of treatment for cervical cancer, in particular psychosocial problems associated with sexuality. The aim of this paper was to explore women's sexuality following treatment for cervical cancer. A qualitative phenomenological design was used to explore the lived experiences of a purposive sample of 13 women 2-3 years after treatment, using in-depth interviewing. The findings demonstrate that cancer treatment can result in a number of late physical effects, including bladder and bowel dysfunction. Moreover, the physical problems led to sexual difficulties experienced several years after treatment. Concerns were expressed by patients about perceived psychosexual difficulties encountered as a result of treatment. In conclusion, the study raises issues associated with the management of late treatment effects and its impact on sexuality. The findings underline the need for effective communication of possible iatrogenic effects of treatment during follow-up care and a need for research to consider the advice and information that women require about long-term treatment effects.

SCOTCERV: A phase II trial of docetaxel and gemcitabine as second-line chemotherapy in cervical cancer

5548

Background: Concurrent Cisplatin chemotherapy along with radiotherapy is standard therapy for locally advanced cervical cancer. There is no established second line regimen. Taxanes and Gemcitabine are not thought to share drug resistance with Cisplatin. In combination they are reasonably tolerated; myelosuppression is the dose limiting toxicity. Response is more likely in recurrences outside the irradiated area. Methods: This was a multi-centre phase II trial of Docetaxel (75mg/m2 d1) and Gemcitabine (1,000 mg/m2 d1,d8) in relapsed patients (pts) after treatment with cisplatin alone or in combination (excluding with taxanes) and/or radiotherapy. A Gehan two-stage design was used (minimum response rate requirement 25%). Pts had to have disease assessable by RECIST outside the irradiated pelvis and adequate organ function. After 12 pts the Docetaxel dose was reduced to 60 mg/m2. Results: 26 eligible pts were recruited to the study; information is available currently for 24. The median age is 43 years (range 30–62) and the median time from prior treatment is 12 months (1–55). 23 pts had prior chemoradiotherapy. Performance status: 0 (15) or 1 (9). Histology: squamous 17, adenoCa (6) mixed (1). Major metastatic sites were lung (11) and para-aortic nodes (11). The principal toxicity was neutropenia (gd 3 (8), gd 4 (8)) with 4 pts experiencing grade 3 febrile neutropenia. Dose reductions occurred in 29% of pts (Docetaxel) and 25% of pts (Gemcitabine), primarily for neutropenic fever. Haematological toxicity resulted in d8 Gemcitabine being omitted in 41% of cycles. 1 patient had gd3 SOB and 1 patient gd 3 diarrhoea. Reduction of Docetaxel dose did not reduce haematological toxicity. 5 pts have not, as yet, had response reported. In 19 pts (16 completed therapy) there was 1 CR, 4 PR, 6 stable disease, 7 progressions and 1 unevaluable. The overall response rate is 26% (95% ci 9%-51%). Conclusions: This preliminary data shows this combination has activity against platinum resistant metastatic cervical cancer, although the ability to deliver d8 Gemcitabine is compromised. Final results will be available for the meeting.

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Rapid development of post-radiotherapy sarcoma and breast cancer in a patient with a novel germline 'de-novo' TP53 mutation

AIMS

Germline mutations in the TP53 tumour suppressor gene are associated with Li-Fraumeni syndrome, which is characterised by a spectrum of neoplasms occurring in children and young adults that predominantly include early-onset breast cancer, a variety of sarcomas, brain tumours and adrenocortical tumours. The identification of patients carrying TP53 mutations is primarily based on a positive family history of these early-onset characteristic cancer types. The aim of this study is to emphasize the importance of TP53 molecular testing in patients with very early onset breast cancer and no family history of cancer.

MATERIALS AND METHODS

A young woman with no family history of cancer presented with bilateral breast cancer at the age of 27 years. Forty months later she developed malignant fibrous histiocytoma of the right clavicle and another primary left breast cancer. Molecular testing of mutations 185delAG, 5382insC in BRCA1 gene and 6174delT in BRCA2 gene was performed using multiplex PCR and separation on a denaturing polyacrylamide gel. TP53 molecular analysis was performed by PCR-SSCP analysis of the whole coding region of the TP53. Exon 8 PCR products were sequenced using an ABI dye terminator kit and examined on an ABI 3100 automated sequencer.

RESULTS

Molecular testing of peripheral blood DNA did not reveal mutations in BRCA1 or BRCA2 genes. A novel germline TP53 mutation, c.G841C, p.D281N, was identified. The detected mutation is a missense substitution, c.G841C, resulting in the substitution of the amino acid aspartate to asparagine, p.D281N. Molecular analysis in her parents showed that neither of them carried the mutation.

CONCLUSIONS

We describe a novel 'de novo'TP53 mutation and discuss the importance of molecular testing in early-onset breast cancer patients and its effect on the management and outcome of the disease.