Lance K. Heilbrun

Thiazide Effect on the Mineral Content of Bone

The thiazide diuretics are known to cause calcium retention. In order to study the effect of thiazides on bone mineralization, we have measured the mineral content of bone at five sites (the distal radius, the distal ulna, the proximal radius, the proximal ulna, and the os calcis) in 1368 men with a mean age of 68 years, including 323 who were taking thiazides for hypertension. The results were adjusted for age and body-mass index. Thiazide users had significantly more bone mineral content at all five sites than did non-users. Untreated hypertensive patients and persons without hypertension had comparable bone mineral content, indicating that the higher mineral content found among thiazide users is related to the drug and not to the underlying hypertension. These findings suggest the possibility of a preventive or therapeutic role for thiazides in osteoporosis.

Loss of Let-7 Up-Regulates EZH2 in Prostate Cancer Consistent with the Acquisition of Cancer Stem Cell Signatures That Are Attenuated by BR-DIM

The emergence of castrate-resistant prostate cancer (CRPC) contributes to the high mortality of patients diagnosed with prostate cancer (PCa), which in part could be attributed to the existence and the emergence of cancer stem cells (CSCs). Recent studies have shown that deregulated expression of microRNAs (miRNAs) contributes to the initiation and progression of PCa. Among several known miRNAs, let-7 family appears to play a key role in the recurrence and progression of PCa by regulating CSCs; however, the mechanism by which let-7 family contributes to PCa aggressiveness is unclear. Enhancer of Zeste homolog 2 (EZH2), a putative target of let-7 family, was demonstrated to control stem cell function. In this study, we found loss of let-7 family with corresponding over-expression of EZH2 in human PCa tissue specimens, especially in higher Gleason grade tumors. Overexpression of let-7 by transfection of let-7 precursors decreased EZH2 expression and repressed clonogenic ability and sphere-forming capacity of PCa cells, which was consistent with inhibition of EZH2 3′UTR luciferase activity. We also found that the treatment of PCa cells with BR-DIM (formulated DIM: 3,3′-diindolylmethane by Bio Response, Boulder, CO, abbreviated as BR-DIM) up-regulated let-7 and down-regulated EZH2 expression, consistent with inhibition of self-renewal and clonogenic capacity. Moreover, BR-DIM intervention in our on-going phase II clinical trial in patients prior to radical prostatectomy showed upregulation of let-7 consistent with down-regulation of EZH2 expression in PCa tissue specimens after BR-DIM intervention. These results suggest that the loss of let-7 mediated increased expression of EZH2 contributes to PCa aggressiveness, which could be attenuated by BR-DIM treatment, and thus BR-DIM is likely to have clinical impact.

Phase II study of gemcitabine and cisplatin in the treatment of patients with advanced pancreatic carcinoma

Pancreatic carcinoma is considered among the most chemoresistant of human malignancies. The most commonly used cytotoxic single agents, 5‐fluorouracil and 2′‐deoxy‐2′,2′‐difluorocytidine (gemcitabine), have objective response rates of less than 10% in large studies. Hypothesizing noncross resistance and a synergistic interaction between gemcitabine and cisplatin, early clinical studies have demonstrated significant activity with this combination in patients with several types of malignant disease. A Phase II study was undertaken to determine the efficacy of gemcitabine in combination with cisplatin in patients with locally advanced and metastatic pancreatic carcinoma based on these considerations.

Chronic oral administration of CI-994: a phase 1 study.

Objectives: CI-994 (N-acetyl dinaline, PD123654) is a novel oral agent active in a broad variety ofmurine and human tumor xenografts. While cytotoxic in theBrown Norway (BN) rat leukemia model, growth inhibition inother murine and human tumor xenografts is predominantlycytostatic. Its specific mechanism of action remains unknown.Following CI-994 administration, inhibition of both histonedeacetylation and cellular proliferation at the G1 to Stransition phase of the cell cycle are observed. This Phase 1study in patients with solid tumors was carried out todetermine a maximum tolerated daily oral dose (MTD) for CI-994administered on a chronic basis. Methods: Fifty-threepatients received CI-994 daily for treatment durations rangingfrom 2 to 10 weeks. Dosage escalation proceeded in 2 phases;an Acute Dosing Phase (n = 11) to define the MTD for CI-994administered over 2 weeks and a Chronic Dosing Phase (n = 29)to define the MTD for daily administration for 8 weeks. Uponcompletion of the Chronic Dosing Phase, a third cohort ofpatients (n = 13) received CI-994 at the recommended Phase 2dose and schedule with 2 additional single doses of drugadministered separated by a 1-week washout to assess theeffect of food on CI-994 pharmacokinetics. Results:Thrombocytopenia was dose limiting at the MTD of 8mg/m2/day for 8 weeks. Other toxicities includedfatigue and gastrointestinal effects such as nausea, vomiting,diarrhea, constipation and mucositis. Pharmacokinetic studiesrevealed that peak plasma levels and AUCs generally increasedwith dose and that food intake did not affect the rate orextent of drug absorption. One patient with heavilypre-treated adenocarcinoma of the lung achieved a PartialResponse (PR) lasting over 2 years and 3 additional patientsachieved Stable Disease (SD), 1 each with non-small cell lung,colorectal, and renal cancer. Conclusions: Therecommended Phase 2 starting dose is 8 mg/m2/dayfor 8 weeks repeated after a 2-week drug-freeinterval.

Protection against mammary tumor growth by vaccination with full- length, modified human ErbB-2 DNA

ErbB‐2 is overexpressed in several human cancers and conveys a transforming activity that is dependent on tyrosine kinase activity. Antibodies and T cells to ErbB‐2 have been isolated from cancer patients, indicating ErbB‐2 as a potential target of active vaccination. In this study, 3 mutant ErbB‐2 DNA constructs encoding full‐length, ErbB‐2 proteins were tested as tumor vaccines. To eliminate tyrosine kinase activity, the ATP binding lysine residue 753 was substituted with alanine by replacing codon AAA with GCA in mutant ErbB‐2A. To direct recombinant ErbB‐2 to the cytoplasm where major histocompatibility complex (MHC) I peptide processing takes place, the endoplasmic reticulum (ER) signal sequence was deleted in cyt ErbB‐2. The third construct cyt ErbB‐2A contained cytoplasmic ErbB‐2 with the K to A mutation. Expression of recombinant proteins was measured by flow cytometry in transfected murine mammary tumor cell line D2F2. Transmembrane ErbB‐2 and ErbB‐2A were readily detected. Cytoplasmic ErbB‐2 and ErbB‐2A were detected only after the transfected cells were incubated overnight with a proteasome inhibitor, indicating prompt degradation upon synthesis. ErbB‐2 autophosphorylation was eliminated by the K to A mutation as demonstrated by Western blot analysis. Growth of ErbB‐2‐positive tumor in BALB/c mice was inhibited after vaccination with ErbB‐2 or ErbB‐2A, but not with cyt ErbB‐2 or cyt ErbB‐2A. ErbB‐2A that is free of tyrosine kinase activity is a potential candidate for anticancer vaccination. The 3 mutant constructs should be useful tools to delineate the role of individual immune effector cell in ErbB‐2‐specific antitumor immunity and to develop strategies for enhancing such immunity. Int. J. Cancer 81:748–754, 1999.

Phase I trial of cixutumumab combined with temsirolimus in patients with advanced cancer

Purpose: Mammalian target of rapamycin (mTOR) inhibitors mediate AKT activation through a type 1 insulin-like growth factor receptor (IGF-1R)–dependent mechanism. Combining the mTOR inhibitor temsirolimus with cixutumumab, a fully human immunoglobulin G1 monoclonal antibody directed against IGF-1R, was expected to enhance mTOR-targeted anticancer activity by modulating resistance to mTOR inhibition. The objectives of this phase I study were to evaluate the tolerability and activity of temsirolimus and cixutumumab. Experimental Design: Patients in sequential cohorts (“3 + 3” design) received escalating doses of temsirolimus with cixutumumab weekly for 28 days. At the maximum tolerated dose (MTD), 21 patients were randomized into three separate drug sequence treatment groups for serial blood draws and 2[18F]fluoro-2-deoxy-d-glucose positron emission tomography combined with X-ray computed tomography (FDG-PET/CT) scans for pharmacodynamic analyses (PD). Results: Forty-two patients with advanced cancer (19 male/23 female, median age = 53, median number of prior therapies = 4) were enrolled. MTD was reached at cixutumumab, 6 mg/kg IV and temsirolimus, 25 mg IV. Dose-limiting toxicities included grade 3 mucositis, febrile neutropenia, and grade 4 thrombocytopenia. The most frequent toxicities were hypercholesterolemia, hypertriglyceridemia, hyperglycemia, thrombocytopenia, and mucositis. Tumor reduction was observed in 2 of 3 patients with Ewings sarcoma and in 4 of 10 patients with adrenocortical carcinoma. PD data suggest that cixutumumab alone or combined with temsirolimus increased plasma IGF-1 and IGF binding protein 3. FDG-PET/CT showed the odds of achieving stable disease decreased by 58% (P = 0.1213) with a one-unit increase in absolute change of standard uptake value from baseline to day 3. Conclusions: Temsirolimus combined with cixutumumab was well tolerated. We are currently enrolling expansion cohorts at the MTD for Ewings sarcoma and adrenocortical carcinoma. Clin Cancer Res; 17(18); 6052–60. ©2011 AACR.

Metastatic squamous cell carcinoma of an unknown primary localized to the neck. Advantages of an aggressive treatment

Treatment of patients with squamous cell carcinoma (SCC) of an unknown primary localized to the neck is still controversial, particularly regarding advanced disease. We reviewed 41 such patients treated with surgery and/or radiotherapy (RT) (n = 25) or with combined modality treatment including chemotherapy (CH) (n = 16). The male to female ratio was 28 to 13, and the median age was 58 years (range, 32 to 94 years). There were 27 (66%) patients with poorly differentiated SCC and 8 with moderately differentiated or well‐differentiated cancer. Twenty‐three (56%) patients had N3 disease, 16 (39%) had N2, and 2 had N1. The majority of N3 patients have been treated with CH and RT (n = 12) or with RT alone (n = 9). The combined CH‐RT was well tolerated, with no life‐threatening toxicity. The complete response (CR) to CH‐RT was 81% (11 patients have no evidence of disease [NED] currently). The median survival time of this group was 37+ months. Of the 25 patients who had surgery and/or RT as their first planned treatment, 7 (28%) have NED currently. The median survival time of this group was 24 months. Patients with N3 disease who received CH had a higher CR rate and a longer survival time as compared with those treated with surgery and/or RT, despite a higher (N3) stage of disease. These findings warrant further investigation in randomized cooperative studies.

A phase II study of bevacizumab, oxaliplatin, and docetaxel in locally advanced and metastatic gastric and gastroesophageal junction cancers.

BACKGROUND Bevacizumab has demonstrated antitumor activity in multiple diseases. This phase II study was undertaken to determine the effects of adding bevacizumab to a regimen of docetaxel and oxaliplatin in patients with advanced adenocarcinoma of the stomach or gastroesophageal junction. PATIENTS AND METHODS Previously untreated patients with locally advanced or metastatic disease and a performance status (PS) of 0-1 were eligible for this study. Patients received bevacizumab at 7.5 mg/kg, docetaxel at 70 mg/m(2), and oxaliplatin at 75 mg/m(2) administered on day 1 of a 21-day cycle. The primary end point of the study was progression-free survival (PFS). RESULTS A total of 38 eligible patients (median age 57 years, 45% gastric, 55% PS 0) were enrolled on to the study. Median PFS was 6.6 months [95% confidence interval (CI) 4.4-10.5] and median survival 11.1 months (95% CI 8.2-15.3). Complete responses were documented in 2 (5%) patients, partial responses in 14 (37%), and stable disease in 14 (37%). No treatment-related deaths were observed. The most commonly reported grade 3-4 toxicity was neutropenia (34%), and gastrointestinal perforation occurred in three patients (8%). CONCLUSION The combination of bevacizumab, docetaxel, and oxaliplatin has promising activity for further evaluation in randomized trials.

A Phase II study of celecoxib, gemcitabine, and cisplatin in advanced pancreatic cancer

SummaryBackground. Pancreatic cancer is amongst the most chemoresistant malignancies. Expression of the cyclooxygenase-2 (COX-2) enzyme plays a major role in tumor progression and resistance to therapy. A Phase II study was undertaken to determine the effect of gemcitabine by fixed-dose rate infusion (FDR), cisplatin and the COX-2 inhibitor, celecoxib, on the 6-month survival rate in patients with metastatic pancreatic cancer.Methods. The eligibility criteria included a pathologically or cytologically confirmed diagnosis of adenocarcinoma of the pancreas. No prior gemcitabine therapy was allowed. Patients received a combination of gemcitabine 1000 mg/m2 over 100 minutes, cisplatin 35 mg/m2 I.V. on days 1 and 8, and celecoxib continuously at a daily dose of 800 mg. Cycles were repeated every 21 days.Results. Twenty-two patients with metastatic pancreas cancer were enrolled (median age, 59.5 years; M:F, 13:9). The median number of cycles was 2 per patient. The median survival time was 5.8 months (90% CI, 3.6–7.6 months). The probability of survival at 6 months was 46% (90% CI, 27–62%). The major toxicity was neutropenia with grade 3 or 4 toxicities seen in 65% of patients.Conclusions. The addition of celecoxib to gemcitabine (by FDR) and cisplatin did not appear to increase activity of the chemotherapy doublet in patients with advanced pancreatic cancer. Celecoxib alone may not be sufficient to sensitize pancreatic cancer to the effects of conventional cytotoxic therapy.

Characteristics of respondents and nonrespondents in a prospective study of osteoporosis

During 1981-1982, a cohort of elderly Japanese Americans living in Hawaii was recruited for an epidemiologic study of osteoporosis. The male subjects were simultaneously being examined for an epidemiologic study of heart disease. Baseline data collected from both the men and women at a previous heart disease examination were used to compare responders vs nonresponders. The target population for the osteoporosis study consisted of 1685 men and 1594 women. Of these, 1379 men (81.8%) and 1105 women (72.0%) participated in the initial osteoporosis examination. For each sex, nonrespondents were older and had higher systolic blood pressure levels than did the respondents. Male nonresponders had a higher stroke prevalence and more frequent recent use of vasodilator medicine. Female nonresponders had a less frequent history of having ever taken female hormones than did the responders. The responders and nonresponders were reasonably similar in other respects, as indicated by the comparison of more than 40 other variables. This suggests that nonresponse bias is probably not a major influence in exposure-disease associations in this osteoporosis cohort. We believe this is the first published report dealing with nonresponse characteristics in a cohort study of osteoporosis.