Maternal and cord steroid sex hormones, angiogenic factors, and insulin-like growth factor axis in African-American preeclamptic and uncomplicated pregnancies

BACKGROUND

A history of a preeclamptic pregnancy has been associated with subsequent increased risk of cardiovascular disease in the mother and decreased risk of breast cancer in both the mother and offspring. The concentrations of steroid sex hormones, angiogenic factors, and other proteins during pregnancy are important components of the in utero environment and may mediate the association of preeclampsia with later health outcomes. This study sought to compare an extensive profile of biological markers in both maternal and umbilical cord samples in preeclamptic and uncomplicated pregnancies of a predominantly African-American population.

METHODS

Steroid sex hormones, angiogenic factors, and components of the insulin-like growth factor axis were measured in maternal and umbilical cord sera from 48 pregnancies complicated by preeclampsia and 43 uncomplicated pregnancies. Regression models estimated the associations of these markers with preeclampsia, after adjusting for maternal and gestational age.

RESULTS

Concentrations of androgens (testosterone p = 0.06 and androstenedione p = 0.08) and the anti-angiogenic factors soluble fms-like kinase 1 (p = 0.004) and soluble endoglin (p = 0.004) were higher in the maternal circulation of women diagnosed with preeclampsia. These findings also were noted when the analyses were restricted to only African-American participants (77% of overall study population). Furthermore, among African-Americans, cord insulin-like growth factor-1 was lower in preeclamptic pregnancies than in controls.

CONCLUSIONS

The associations of maternal androgens and anti-angiogenic factors with preeclampsia are consistent with prior reports from predominantly Caucasian populations. Alterations in these analytes as well as other maternal and fetal biomarkers in preeclampsia could mediate the associations of preeclampsia with later health consequences.

Abstract LB-323: Self-reported sleep duration and subsequent risk of colorectal cancer in two large cohorts of women and men

Background: Short sleep duration was associated with an increased risk of colorectal adenomas in a recent report. To date, no data are available on the relationship between sleep duration and colorectal cancer risk. Method: We prospectively followed 76,368 women aged 40 to 73 years in the Nurses’ Health Study and 28,676 men aged 41 to 79 years in the Health Professionals Follow-up Study who reported their habitual sleep duration in the mid-1980s. We used Cox proportional hazards regression models to estimate multivariable relative risks (MV RRs) and 95% confidence intervals (CIs) adjusting for known risk factors (dietary and non-dietary) for colorectal cancer. Results: A total of 1,925 incident colorectal cancer cases (1,264 in women and 661 in men) were documented during up to 22 years of follow-up. The median of sleep duration was 7 hours in both cohorts and was used as the reference group. In both age-adjusted and the multivariate models, long sleep duration (i.e., at least 9 hours of sleep) was significantly positively associated with risk of colorectal cancer in men (MV RR=1.49; 95%CI: 1.10, 2.03) but not in women (MV RR=1.10; 95%CI: 0.85, 1.43). However, for the same comparison (i.e., at least 9 hours vs. 7 hours of sleep), among overweight (body mass index at least 25 kg/m2) individuals, we found significant positive associations for both men (MV RR=2.66; 95%CI: 1.81, 3.90) and women (MV RR=1.42; 95%CI: 1.01, 1.99). Short sleep duration (i.e., 5 hours or less of sleep) was not associated with colorectal cancer risk in either men (MV RR=0.65; 95%CI: 0.33, 1.28) or women (MV RR=1.14; 95%CI: 0.88, 1.48). Results were essentially unchanged when we excluded cases occurred in the first 4 years of follow-up. In addition, the association was not significantly modified by physical activity, alcohol consumption, endoscopy screening, family history of colorectal cancer, menopausal status, or shift work (women only). Conclusion: These prospective data from two large cohorts suggest that overweight men and women with a sleep duration of 9 or longer hours had a significantly increased risk of developing colorectal cancer when compared to those with 7 hours of sleep, which cannot be explained by known risk factors or reverse causality. The potential mechanisms behind this association deserve further investigation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-323. doi:1538-7445.AM2012-LB-323

Abstract 4501: Energetic risk and prostate cancer-specific and all-cause mortality in two large cohorts of men with localized prostate cancer

Objective: To examine whether high energetic risk predisposes men with localized prostate cancer (PC) to higher risk of PC-specific mortality or all-cause mortality. Methods: Among men with localized PC, prediagnostic body mass index (BMI) and plasma C-peptide (a marker of insulin production) were available for 691 men (301 overall deaths, 78 PC deaths) in the Physicians’ Health Study (discovery set) and 1111 men (262 overall deaths, 56 PC deaths) in the Health Professionals Follow-up Study (validation set). High energetic risk was defined as BMI 25-29.9 kg/m2 and C-peptide in the highest quartile or BMIα30 kg/m2. We used the Cox-regression model to estimate risk, adjusting for age, smoking, diabetes, and D'Amico risk defined by stage, Gleason grade and prostate-specific antigen (PSA). Results: Results were similar in both cohorts; the combined hazard ratio (HR)s (95% confidence interval, CI) associated with high energetic risk (25% of study population) were 2.2 (1.5-3.3) for PC-specific mortality and 1.4 (1.1-1.7) for all-cause mortality. The risk of PC-specific mortality according to low- intermediate-, or high-D'Amico risk were 1.0 (reference), 2.6, 6.4 for low energetic risk, and 5.0, 6.1, 9.4 for high energetic risk. The corresponding HRs for all-cause mortality were 1.0 (reference), 1.3, 2.1, 2.1, 2.1, and 2.3. Compared to D'Amico risk alone, incorporating energetic risk significantly improved the predictability of PC-specific mortality (C-statistic from 0.72 to 0.78, P<0.001). Conclusion: Adding energetic risk to D'Amico risk groups significantly improved prediction of PC-specific and all-cause mortality, and identifies 20% D'Amico “low-risk” patients who may be poor candidates for active surveillance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4501. doi:1538-7445.AM2012-4501

The insulin receptor/insulin-like growth factor receptor family as a therapeutic target in oncology

Over the past decade, encouraging preclinical and early clinical data concerning the relevance of the insulin receptor/insulin-like growth factor (IGF) receptor family to neoplasia led to ambitious clinical trial programs of more than a dozen drug candidates that target these receptors. These candidates include antireceptor antibodies, antiligand antibodies, receptor-specific tyrosine kinase inhibitors, and agents such as picropodophyllin and metformin that have novel mechanisms of action. Several recently reported phase III clinical trials of anti-IGF-I receptor antibodies have been disappointing and are sufficient to disprove the hypothesis that the antibodies tested have large favorable impacts on unselected patients with cancer. However, many of these trials were designed prior to recent insights concerning pathophysiology and predictive biomarkers. Future studies are required, but it will be important to optimize their design rather than simply repeat the approaches taken to date.

Metformin and hepatic carcinogenesis

Retrospective, hypothesis-generating population studies suggest that diabetics treated with metformin have a substantially reduced risk of several cancers, including hepatoma, relative to diabetics on other therapies. In this issue of the journal (beginning on page 544), Bhalla and colleagues contribute to the growing literature on metformin effects in experimental carcinogenesis models, showing reduced carcinogen-induced hepatoma in mice. The clinical need to develop novel prevention strategies for hepatoma is obvious, given an increasing prevalence and poor prognosis. The clues that metformin or related biguanides may have utility in this area justify accelerated laboratory research, as more data concerning mechanism, pharmacokinetics, and predictors of efficacy will help to optimize the design of clinical trials.

The insulin and insulin-like growth factor receptor family in neoplasia: an update

Although several early phase clinical trials raised enthusiasm for the use of insulin-like growth factor I receptor (IGF1R)-specific antibodies for cancer treatment, initial Phase III results in unselected patients have been disappointing. Further clinical studies may benefit from the use of predictive biomarkers to identify probable responders, the use of rational combination therapies and the consideration of alternative targeting strategies, such as ligand-specific antibodies and receptor-specific tyrosine kinase inhibitors. Targeting insulin and IGF signalling also needs to be considered in the broader context of the pathophysiology that relates obesity and diabetes to neoplasia, and the effects of anti-diabetic drugs, including metformin, on cancer risk and prognosis. The insulin and IGFI receptor family is also relevant to the development of PI3K-AKT pathway inhibitors.

Abstract A15: A phase 2 study of neoadjuvant metformin in prostatic carcinoma

Background: Metformin is an inhibitor of the complex 1 in the respiratory chain, and is widely used in diabetes due to its effect on reducing insulin resistance. It has also been recently described to have effects via AMPK on inhibiting the mTOR kinase. Significant preclinical and epidemiological studies suggest its role in chemoprevention. These actions provide significant rationale to evaluate its utility in prostate cancer. We conducted a phase II single centre study of neoadjuvant metformin in localized prostate cancer.

Methods: Men were required to have histologically confirmed prostate cancer involving at least 20% of at least 1 unfragmented biopsy core. Exclusion criteria included patients who on initial assessment are found to be on treatment with any drug used for the treatment of any form of diabetes, or patients that begin treatment for any form of diabetes during the course of the study. Pts were treated with up to 500mg tid of metformin. The primary objectives were to demonstrate safety and tolerability of neoadjuvant metformin administration in men with prostate cancer and to document changes in phospho-AKT signaling indices.

Results: 24 patients were enrolled with 22 evaluable; median age was 64 yrs (range, 45-70 yrs). Baseline characteristics included median PSA 6 ng/mL (range, 3.22–36.11 ng/mL). Median duration of drug treatment was 41 days (range 18–81). No grade 3 adverse events were reported, all patients underwent subsequent radical prostatectomy with adverse effects related to metformin. Significant pre-and post changes were noted in serum IGF1 (p=0.02), fasting glucose (p=0.03), BMI (p < 0.01) and waist/hip ratio (p < 0.01). There was a trend for a PSA reduction (p=0.08). There were no correlations between any metabolic, morphometric or cancer-related serum indices.

Conclusions: Neoadjuvant metformin is well tolerated prior to radical prostatectomy. Data to date indicates promising effects on metabolic parameters, tissue results will be presented including proliferation indices and signaling pathway assessments.

Citation Format: Anthony Michael Joshua, Neil Fleshner, Michael Pollak, Vanessa Zannella, Barbara Bowes, Marianne Koritzinsky, Joan Sweet, Andrew Evans, John Trachtenberg, Michael Jewett, Antonio Finelli. A phase 2 study of neoadjuvant metformin in prostatic carcinoma [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr A15.

P2-12-28: Studies of a Malignancy-Associated Protein, Osteopontin, in NCIC CTG MA.14, a Randomized Trial of Tamoxifen Versus Combined Tamoxifen and Octreotide LAR in Adjuvant Treatment of Women with Early Breast Cancer

Background

We have shown, in women with metastatic breast cancer (BC), that high baseline plasma osteopontin (OPN) levels and increases over time are associated with poor survival. In primary BC, increased immunohistochemical (IHC) expression of OPN in tumour is associated with poorer survival and is elevated in lymph node metastases relative to primary tumour. Our current study evaluates tumour and baseline/serial plasma OPN levels after resection of primary BC.

Methods: In NCIC CTG MA.14, 667 postmenopausal women post surgery received 5 yrs Tamoxifen (T) +/− 2 yrs monthly Octreotide LAR. There were no differences in survival outcomes between arms. OPN was assayed by IHC in primary BC. OPN was measured in plasma at baseline (up to 4 mos post randomization) and serially in recurrent (18 mos time window) versus non-recurrent cases, by ELISA. Statistical Analysis: IHC and plasma OPN had Box-Cox variance stabilization transformations (power 0.5; logarithm). Descriptive characterization of both OPN measurements is provided for all patients, by baseline patient and tumour characteristics, and by recurrence status. Univariate stratified log-rank statistics and hazard ratios with 95% CI were generated for intention to treat (ITT), event free survival (EFS), relapse fee survival (RFS), overall survival, any bone RFS, and non-bone RFS. Stratified step-wise forward Cox regression was used, with factor added if p<0.05.

Results: From 667 MA.14 patients, 647 patients were assessed for OPN: 462 (69%) by IHC; 387 (58%) at baseline in plasma (with 2,542 samples total from serial sampling). IHC % tumor positivity had mean 33.9% (95% CI 30.2%-37.9%), while baseline plasma OPN was mean 46.1 (44.6−47.6) ng/ml. In 80 women with recurrence, mean OPN during the recurrence window was 60.7 (52.8−69.8) ng/ml. Neither baseline IHC or plasma OPN levels were significantly associated with any of the endpoints in either univariate or multivariate analyses. Older age (p=0.02), greater nodal involvement (p=0.001), higher baseline body mass index (p<0.0001), and higher tumour grade (p<0.0001) were multivariately associated with shorter EFS. Baseline plasma OPN was not correlated with IHC OPN (Pearson 0.02, p=0.73).

Discussion: Mean baseline OPN plasma level 46.1 ng/ml (median 45 ng/ml) in MA.14 was similar to our previous findings in healthy women (median 47 ng/ml). In contrast, we previously showed that 63% of 158 women with a new diagnosis of metastatic BC had elevated OPN levels with median value 177 ng/ml. Our results thus far suggest that tumor and plasma levels, while associated with prognosis in metastatic BC, may not be so in primary BC following surgery. However, in MA.14, the 80 women with recurrent BC had significantly higher mean OPN in the recurrence window, 60.7 ng/ml, than at baseline. We will present further analyses exploring this finding.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-12-28.

MS3-3: Energy Metabolism in Breast Cancer: Translational Science Insights Relevant to Effects of Diet, Exercise, and Metformin on Risk and Prognosis

Energy metabolism is relevant to breast cancer at both the cellular and whole organism levels. Whole organism energy balance determines body mass, which has been associated with variations in both breast cancer risk and prognosis. Experimentally, breast carcinogenesis is facilitated by excess caloric intake and inhibited by caloric restriction. The simplistic notion that excess food intake provides additional energy to breast epithelial cells at risk for transformation or to breast cancers, leading to aggressive behavior, is not supported by experimental data. Rather, variations in energy balance have important influences on the hormonal and cytokine environment of the patient, and these influence carcinogenesis and tumor behaviour. Experimental models provide evidence that one such mediating hormone is insulin. Most breast cancers have insulin receptors. When mice with breast cancer are experimentally manipulated to have insulin deficiency (type I) diabetes, tumor growth rate is slowed (despite hyperglycemia). Conversley, when mice are provided with a “junk food” diet, insulin levels rise, tumor insulin receptor activation increases, and tumors grow more quickly. However, when breast cancers evolve to have activating muations in signalling networks downstream of insulin receptors, they become more aggressive and unresponsive to variations in energy intake and insulin no longer influences their behavior.

There is retrospective pharmacoepidemiologic evidence for a substantial ( ∼50%) reduction in breast cancer risk in type II (hyperinsulinemic) diabetic patients prescribed metformin. This has contributed to current interest in the hypothesis that metformin has uses in cancer prevention or treatment. Metformin acts to reduce cellular ATP production by inhibiting mitochondrial respiratory complex I. This results in activation of AMPK. In liver, this results in reduced gluconeogenesis, which reduces the hyperglycemia and hyperinsulinemia of type II diabetes. This systemic effect may reduce proliferation of the subset of neoplasms that are growth stimulated by insulin, but does not operate in the absence of baseline hyperinsulinemia. Other mechanisms of metformin action involve direct effects on at-risk or transformed cells. These mechanisms require adequate levels of the drug in the relevant cells, but metformin doses used in diabetes treatment may not achieve optimum concentrations in cancers, particularly those that lack the active transport molecules responsible for cellular metformin uptake. Overall, laboratory studies suggest that any benefits of metformin will not be homogeneous among a population of at-risk women in a prevention context, nor among breast cancer patients in a treatment context. The validation of candidate predictive biomarkers for metformin benefit, together with more detailed pharmokinetic data, may allow for optimized clinical trial design. Further research is also required to clarify if metformin should best be evaluated as a single agent or in combinations. Thus, metformin and derivatives can be regarded as lead compounds for optimization, and this line of research may lead to novel metabolic approaches to breat cancer prevention and treatment.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr MS3-3.

IGF1/insulin receptor kinase inhibition by BMS-536924 is better tolerated than alloxan-induced hypoinsulinemia and more effective than metformin in the treatment of experimental insulin-responsive breast cancer

Epidemiologic and experimental evidence suggest that a subset of breast cancer is insulin responsive, but it is unclear whether safe and effective therapies that target the insulin receptor (IR), which is homologous to oncogenes of the tyrosine kinase class, can be developed. We demonstrate that both pharmacologic inhibition of IR family tyrosine kinase activity and insulin deficiency have anti-neoplastic activity in a model of insulin-responsive breast cancer. Unexpectedly, in contrast to insulin deficiency, pharmacologic IR family inhibition does not lead to significant hyperglycemia and is well tolerated. We show that pharmacokinetic factors explain the tolerability of receptor inhibition relative to insulin deficiency, as the small molecule receptor kinase inhibitor BMS-536924 does not accumulate in muscle at levels sufficient to block insulin-stimulated glucose uptake. Metformin, which lowers insulin levels only in settings of hyperinsulinemia, had minimal activity in this normoinsulinemic model. These findings highlight the importance of tissue-specific drug accumulation as a determinant of efficacy and toxicity of tyrosine kinase inhibitors and suggest that therapeutic targeting of the IR family for cancer treatment is practical.

Associations of pregnancy characteristics with maternal and cord steroid hormones, angiogenic factors, and insulin-like growth factor axis

BACKGROUND

The objective of this study was to comprehensively profile biological factors in pregnancy that have been postulated to be important components of the in utero environment and may also have relevance to later susceptibility to cancer and other chronic diseases.

METHODS

Steroid sex hormones, IGFs, and angiogenic factors were measured in maternal and cord serum from term normotensive pregnancies. Spearman correlations and linear regression estimated relationships among the biological factors and clinical characteristics.

RESULTS

The analytes were generally not correlated between maternal and fetal circulations. However, significant correlations were demonstrated among several analytes within maternal or cord samples. A few analytes were associated with clinical characteristics (e.g., maternal IGF-1 and IGFBP-3 were inversely correlated with offspring birth weight, while maternal leptin and cord testosterone were positively correlated with this characteristic). Maternal androgens were higher in African-Americans than whites, and maternal PlGF and soluble fms-like tyrosine kinase-1 (sFlt-1) were higher in male than female offspring.

CONCLUSIONS

There were significant correlations among analytes, but the patterns differed depending on whether they were measured in the maternal or fetal circulation. The number and magnitude of correlations among analytes, however, should affect the design and interpretation of future studies.

Relevance of the OCT1 transporter to the antineoplastic effect of biguanides

Epidemiologic and laboratory data suggesting that metformin has antineoplastic activity have led to ongoing clinical trials. However, pharmacokinetic issues that may influence metformin activity have not been studied in detail. The organic cation transporter 1 (OCT1) is known to play an important role in cellular uptake of metformin in the liver. We show that siRNA knockdown of OCT1 reduced sensitivity of epithelial ovarian cancer cells to metformin, but interestingly not to another biguanide, phenformin, with respect to both activation of AMP kinase and inhibition of proliferation. We observed that there is heterogeneity between primary human tumors with respect to OCT1 expression. These results suggest that there may be settings where drug uptake limits direct action of metformin on neoplastic cells, raising the possibility that metformin may not be the optimal biguanide for clinical investigation.

Abstract B95: A dietary pattern that is associated with C-peptide and risk of colorectal cancer in women

Higher serum C-peptide concentrations is associated with increased risk of colorectal cancer (CRC). Therefore, we used diet and C-peptide information from a subsample of women from a large cohort and applied stepwise linear regression to identify food groups that correlated with serum levels of C-peptide. These food contributors then formed dietary patterns for predicting the risk of CRC in the main cohort of women. In up to 22 years of follow-up, we ascertained 985 cases of CRC and 758 colon cancer cases. After adjusting for confounders, we observed that the C-peptide pattern, characterized by higher meat, fish, and sweetened beverage intake, but lower coffee, high fat dairy, and whole grains intake, showed direct association with CRC risk (comparing extreme quintiles, RR=1.35, 95% CI=1.07–1.70. p trend=0.009). In stratified analysis, we did not observe an association between the C-peptide pattern and colon cancer among lean and active women (RR comparing extreme quintiles=0.84, 95% CI=0.50–1.41, p trend=0.23). However, among women who were overweight or sedentary, RR for the same comparison was 1.58 (95% CI=1.20–2.07, p trend=0.002) (p for interaction=0.007). In addition, the association between the C peptide pattern and serum C peptide concentrations is also stronger in the sedentary or overweight group (r=0.23, p<0.0001 vs r=0.15, p=0.01 among lean and active women). In conclusion, we derived a dietary pattern that correlated with C peptide concentrations. This pattern was associated with an increase of colon cancer, especially among women who were at risk for insulin resistance.

Citation Information: Cancer Prev Res 2011;4(10 Suppl):B95.

Common polymorphisms in the adiponectin and its receptor genes, adiponectin levels and the risk of prostate cancer

BACKGROUND

Adiponectin, an insulin-sensitizing adipokine, is inversely associated with adiposity and prostate cancer risk and progression. However, the role of genetic variation in the adiponectin (ADIPOQ) and receptor genes (ADIPOR1/R2) in prostate cancer is largely unknown.

METHODS

In a nested case-control study of 1,286 cases and 1,267 controls within the Physicians' Health Study, we evaluated 29 common single-nucleotide polymorphisms (SNP) in ADIPOQ (n = 13), ADIPOR1 (n = 5), and ADIPOR2 (n = 11) in relation to the risk of prostate cancer. In subgroups, we also evaluated the association of genotype and circulating adiponectin levels (n = 951) and prostate tumor expression of insulin receptor (IR) and insulin-like growth factor 1 (IGF-IR) receptor (n = 181).

RESULTS

Among the 12 tagging polymorphisms in ADIPOQ, four (rs266729, rs182052, rs822391, and rs2082940) were significantly associated (P < 0.05) with overall prostate cancer risk, with no significant difference by tumor grade or clinical stage. Two of the risk SNPs (rs266729 and rs182052) plus four other SNPs (rs16861209, rs17366568, rs3774261, and rs7639352) were also associated with plasma adiponectin levels, and three of these (rs1686109, rs17366568, and rs3774261) were also significantly associated with IR expression in prostate tumor tissue. One additional SNP was associated with IGFI-R tumor tissue expression (rs16861205). None of the 16 variants in ADIPOR1/R2 were related to cancer risk or circulating adiponectin levels.

CONCLUSIONS

Common variants in the adiponectin gene were associated with prostate cancer risk, plasma adiponectin levels, and IR or IGF-IR expression in the prostate tumor.

IMPACT

These genotype-phenotype associations support the biological relevance of adiponectin for prostate carcinogenesis, particularly in earlier stages of development.

A prospective study of intakes of zinc and heme iron and colorectal cancer risk in men and women

Although laboratory studies linked zinc and heme iron to colorectal cancer, epidemiologic evidence is limited. We prospectively examined these associations in the Nurses' Health Study and Health Professionals Follow-up Study. We used Cox proportional hazards regression analyses to calculate cohort-specific relative risks (RRs) and pooled results using a fixed-effects model. We documented 2,114 incident colorectal cancer cases during up to 22 years of follow-up. Compared highest to lowest quintile of dietary zinc intake, the pooled multivariable RRs (95% CIs) were 0.86 (0.73, 1.02) for colorectal cancer, 0.92 (0.76, 1.11) for colon cancer, and 0.68 (0.47, 0.99) for rectal cancer. The significant inverse association between dietary zinc intake and risk of rectal cancer was mainly driven by data in women, although the difference in the sex-specific results was not statistically significant. For the same comparison, the pooled multivariable RRs (95% CIs) for heme iron were 1.10 (0.93, 1.30) for colorectal cancer, 1.06 (0.88, 1.29) for colon cancer, and 1.20 (0.83, 1.75) for rectal cancer. These associations were not significantly modified by alcohol consumption, body mass index, physical activity, menopausal status, or postmenopausal hormone use. Total zinc intake, total iron intake, dietary iron intake, and zinc or iron supplement uses were largely not associated with colorectal cancer risk. Our study does not support strong roles of zinc and heme iron intake in colorectal cancer risk; however, a suggestive inverse association of dietary zinc intake with rectal cancer risk in women requires further study.

Long-term effects of insulin glargine on the risk of breast cancer

AIMS/HYPOTHESIS

There have been growing concerns regarding the long-term effects of insulin glargine (A21Gly,B31Arg,B32Arg human insulin) on the risk of breast cancer.

METHODS

We used the UK's General Practice Research Database (GPRD) to identify a cohort of women aged 40 years or over with type 2 diabetes, treated with insulin during 2002-2006 and followed until the first breast cancer diagnosis or 31 December 2009. After the users of insulin glargine had been matched with users of other insulins on age, calendar time and duration of prior insulin use, the HR of breast cancer associated with insulin glargine use was estimated using a Cox proportional hazards model, adjusted for known risk factors for breast cancer.

RESULTS

The cohort comprised 15,227 women, including 4,579 glargine users and 10,648 users of other insulins, of which 246 developed breast cancer during up to 8 years follow-up (incidence rate 4.1 per 1,000 per year). Insulin glargine use was not associated with an increased risk of breast cancer during the first 5 years of use (HR 0.9; 95% CI 0.7-1.3). The risk tended to increase after 5 years (HR 1.8; 95% CI 0.8-4.0), and significantly so for the women who had been on insulin before starting glargine (HR 2.7; 95% CI 1.1-6.5).

CONCLUSIONS/INTERPRETATION

The risk of breast cancer in women with type 2 diabetes is not increased during the first 5 years of insulin glargine use. However, longer-term use may increase this risk, particularly in women with longstanding use of insulin before starting insulin glargine.

Elevated bone turnover predicts for bone metastasis in postmenopausal breast cancer: results of NCIC CTG MA.14

PURPOSE

We investigated the association of bone-only relapse with a pretreatment marker of bone resorption: serum beta C-terminal telopeptide (B-CTx) of type I collagen.

METHODS

Pretreatment serum B-CTx concentrations were determined from 621 of 667 patients with primary breast cancer enrolled onto the NCIC CTG MA.14 phase III adjuvant trial of tamoxifen with or without octreotide. Recurrence-free survival (RFS) was a secondary end point; the focus here was bone-only relapse. We analyzed continuous or categorical (.71 ng/mL cut point) serum B-CTx in stepwise forward multivariate Cox regression, adjusted for trial stratification factors. We also examined B-CTx and bone relapse by pretrial chemotherapy status.

RESULTS

At median 7.9 years follow-up, 123 of 621 patients experienced recurrence; 19 (3.1%) of 621 had bone-only recurrence, and 47 (7.5%) of 621 had bone plus other sites of recurrence. Larger pathologic tumor size (P = .001) and elevated continuous and categorical serum B-CTx were associated with shorter bone-only RFS (both P = .02) when added to a model with factors significant in the main trial analyses (hazard ratio [HR], 3.43 and 3.50, respectively; 95% CI, 1.20 to 9.77 and 1.26 to 9.75, respectively). The univariate HR for B-CTx was 2.80 (95% CI, 1.05 to 7.48; P = .03). Elevated serum B-CTx was also associated with shorter bone-only RFS (P = .02) when added to a model with factors significant in the main trial analyses. Serum B-CTx level was not associated with any other type of recurrence. Serum B-CTx was not significantly different for patients who underwent pretrial chemotherapy, compared with those who did not (P = .27), nor did pretrial chemotherapy affect bone relapse (P = .48 for bone only; P = .76 for bone with other relapse).

CONCLUSION

Higher pretreatment serum B-CTx was a significant predictor of shorter RFS for bone-only metastasis. Increased bone resorption creates an environment that promotes growth of breast cancer cells.

Metformin abolishes increased tumor (18)F-2-fluoro-2-deoxy-D-glucose uptake associated with a high energy diet

Insulin regulates glucose uptake by normal tissues. Although there is evidence that certain cancers are growth-stimulated by insulin, the possibility that insulin influences tumor glucose uptake as assessed by ( 18) F-2-Fluoro-2-Deoxy-d-Glucose Positron Emission Tomography (FDG-PET) has not been studied in detail. We present a model of diet-induced hyperinsulinemia associated with increased insulin receptor activation in neoplastic tissue and with increased tumor FDG-PET image intensity. Metformin abolished the diet-induced increases in serum insulin level, tumor insulin receptor activation and tumor FDG uptake associated with the high energy diet but had no effect on these measurements in mice on a control diet. These findings provide the first functional imaging correlate of the well-known adverse effect of caloric excess on cancer outcome. They demonstrate that, for a subset of neoplasms, diet and insulin are variables that affect tumor FDG uptake and have implications for design of clinical trials of metformin as an antineoplastic agent.

High-level IGF1R expression is required for leukemia-initiating cell activity in T-ALL and is supported by Notch signaling

Notch-driven expression of IGF1R promotes the growth, viability, and transplantability of T-ALL cells.

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive cancer of immature T cells that often shows aberrant activation of Notch1 and PI3K–Akt pathways. Although mutations that activate PI3K–Akt signaling have previously been identified, the relative contribution of growth factor-dependent activation is unclear. We show here that pharmacologic inhibition or genetic deletion of insulin-like growth factor 1 receptor (IGF1R) blocks the growth and viability of T-ALL cells, whereas moderate diminution of IGF1R signaling compromises leukemia-initiating cell (LIC) activity as defined by transplantability in syngeneic/congenic secondary recipients. Furthermore, IGF1R is a Notch1 target, and Notch1 signaling is required to maintain IGF1R expression at high levels in T-ALL cells. These findings suggest effects of Notch on LIC activity may be mediated in part by enhancing the responsiveness of T-ALL cells to ambient growth factors, and provide strong rationale for use of IGF1R inhibitors to improve initial response to therapy and to achieve long-term cure of patients with T-ALL.

A tripartite complex composed of ETV6-NTRK3, IRS1 and IGF1R is required for ETV6-NTRK3-mediated membrane localization and transformation

ETV6-NTRK3 (EN), a chimeric tyrosine kinase generated by t(12;15) translocations, is a dominantly acting oncoprotein in diverse tumor types. We previously showed that insulin-like growth factor 1 receptor (IGF1R) is essential for EN-mediated oncogenesis and that insulin receptor substrate 1 (IRS1) is constitutively tyrosine phosphorylated and bound by EN in transformed cells. Given that IRS1 is also an adapter for IGF1R, we hypothesized that IRS1 might localize EN to IGF1R at the membrane to activate phosphatidylinositol 3-kinase (PI3K)-Akt, which is critical for EN oncogenesis. In this study, we examined EN/IRS1/IGF1R complexes in detail. We find that both IRS1 and kinase active IGF1R are required for EN transformation, that tyrosine phosphorylated IRS1 is present in high molecular weight complexes with EN and IGF1R, and that EN colocalizes with IGF1R at the plasma membrane. Both IGF1R kinase activity and an intact cytoplasmic Y950 residue, the IRS1-docking site of IGF1R, are required, confirming the importance of the IGF1R/IRS1 interaction for EN oncogenesis. The dual specificity IGF1R and insulin receptor (INSR) inhibitor, BMS-536924, blocks EN transformation activity, cell survival and its interaction with IRS proteins, and induces a striking shift of EN proteins to smaller sized molecular complexes. We conclude that a tripartite complex of EN, IRS1 and IGF1R localizes EN to the membrane and that this is essential for EN-mediated transformation. These findings provide an explanation for the observed IGF1R dependency of EN transformation. Blocking IGF1R kinase activity may, therefore, provide a tractable therapeutic strategy for the many tumor types driven by the EN oncoprotein.