Overcoming negative predictions of microRNA expressions to gemcitabine response with FOLFIRINOX in advanced pancreatic cancer patients

FOLFIRINOX is superior to gemcitabine in patients with pancreatic cancer, but this regimen is associated with toxicity and biomarkers for response are warranted. MicroRNAs can mediate drug resistance and could provide predictive information. Altered expressions of several microRNAs including miR-21-5p, miR-10b-5p and miR-34a-5p have been previously linked to a worse response to gemcitabine. We investigated the influence of expression levels in tumor tissue of those three microRNAs on outcome to FOLFIRINOX. Twenty-nine patients with sufficient formalin-fixed paraffin-embedded tumor tissue were identified. There was no significant association between high and low expression groups for these three microRNA. We conclude that polychemotherapy combination can overcome intrinsic negative prognostic factors.

FOLFIRINOX for locally advanced pancreatic cancer: a systematic review and patient-level meta-analysis

BACKGROUND

35% of patients with pancreatic cancer have unresectable locally advanced disease at diagnosis. Several studies have examined systemic chemotherapy with FOLFIRINOX (leucovorin and fluorouracil plus irinotecan and oxaliplatin) in patients with locally advanced pancreatic cancer. We aimed to assess the effectiveness of FOLFIRINOX as first-line treatment in this patient population.

METHODS

We systematically searched Embase, MEDLINE (OvidSP), Web of Science, Scopus, PubMed Publisher, Cochrane, and Google Scholar from July 1, 1994, to July 2, 2015, for studies of treatment-naive patients of any age who received FOLFIRINOX as first-line treatment of locally advanced pancreatic cancer. Our primary outcome was overall survival. Secondary outcomes were progression-free survival; rates of grade 3 or 4 adverse events; and the proportion of patients who underwent radiotherapy or chemoradiotherapy, surgical resection after FOLFIRINOX, and R0 resection. We evaluated survival outcomes with the Kaplan-Meier method with patient-level data. Grade 3 or 4 adverse events, and the proportion of patients who underwent subsequent radiotherapy or chemoradiotherapy or resection, were pooled in a random-effects model.

FINDINGS

We included 13 studies comprising 689 patients, of whom 355 (52%) patients had locally advanced pancreatic cancer. 11 studies, comprising 315 patients with locally advanced disease, reported survival outcomes and were eligible for patient-level meta-analysis. Median overall survival from the start of FOLFIRINOX ranged from 10·0 months (95% CI 4·0-16·0) to 32·7 months (23·1-42·3) across studies with a pooled patient-level median overall survival of 24·2 months (95% CI 21·7-26·8). Median progression-free survival ranged from 3·0 months (95% CI not calculable) to 20·4 months (6·5-34·3) across studies with a patient-level median progression-free survival of 15·0 months (95% 13·8-16·2). In ten studies comprising 490 patients, 296 grade 3 or 4 adverse events were reported (60·4 events per 100 patients). No deaths were attributed to FOLFIRINOX toxicity. The proportion of patients who underwent radiotherapy or chemoradiotherapy ranged from 31% to 100% across studies. In eight studies, 154 (57%) of 271 patients received radiotherapy or chemoradiotherapy after FOLFIRINOX. The pooled proportion of patients who received any radiotherapy treatment was 63·5% (95% CI 43·3-81·6, I(2) 90%). The proportion of patients who underwent surgical resection for locally advanced pancreatic cancer ranged from 0% to 43%. The proportion of patients who had R0 resection of those who underwent resection ranged from 50% to 100% across studies. In 12 studies, 91 (28%) of 325 patients underwent resection after FOLFIRINOX. The pooled proportion of patients who had resection was 25·9% (95% CI 20·2-31·9, I(2) 24%). R0 resection was reported in 60 (74%) of 81 patients. The pooled proportion of patients who had R0 resection was 78·4% (95% CI 60·2-92·2, I(2) 64%).

INTERPRETATION

Patients with locally advanced pancreatic cancer treated with FOLFIRINOX had a median overall survival of 24·2 months-longer than that reported with gemcitabine (6-13 months). Future research should assess these promising results in a randomised controlled trial, and should establish which patients might benefit from radiotherapy or chemoradiotherapy or resection after FOLFIRINOX.

FUNDING

None.

Cytomegalovirus reactivation and its clinical impact in patients with solid tumors

Cytomegalovirus reactivation can be life threatening. However, little evidence on its incidence in solid cancers is available. Therefore our single center Cytomegalovirus polymerase chain reaction database with altogether 890 CMV positive blood serum samples of mainly hematological and oncological patients was retrospectively analyzed to examine the occurrence of Cytomegalovirus reactivation in patients with solid tumors, resulting in 107 patients tested positive for Cytomegalovirus reactivation. Seventeen patients with solid cancer and a positive CMV-PCR test were identified, of which eight patients had clinically relevant CMV disease and received prompt antiviral treatment. Five patients fully recovered, but despite prompt antiviral treatment three patients died. Among these three patients two had significant co-infections (in one case EBV and in the other case Aspergillus) indicating that that CMV reactivation was at least one factor contributing to sepsis. The patient with the EBV co-infection was treated in an adjuvant therapy setting for breast cancer and died due to Cytomegalovirus and Epstein-Barr virus associated pneumonia despite intensive therapy. The other two patients had progressive disease of an underlying pancreatic cancer at the time of CMV diagnosis. One patient died due to attendant uncontrollable Aspergillus pneumonia, the other patient most likely died independent from CMV disease because of massively progressive underlying disease.

Cytomegalovirus reactivation and disease might be underestimated in routine clinical practice. In our retrospective analysis we show that approximately 50 % of our patients suffering from solid cancers with a positive Cytomegalovirus polymerase chain reaction also had clinically relevant Cytomegalovirus disease requiring antiviral therapy.

Relations of vitamin D status, gender and type 2 diabetes in middle-aged Caucasians

Vitamin D (Vit D) deficiency may be linked to the development of obesity-associated complications such as insulin resistance and type 2 diabetes. We therefore evaluated the relationship of Vit D serum concentrations with metabolic parameters and type 2 diabetes in middle-aged Caucasian men and women. One thousand six hundred and thirty-one Caucasians (832 males, 58.8 ± 9.7 years; 799 females, 59.7 ± 10.7 years) were evaluated in a cross-sectional study. Vit D status was assessed by measuring the serum concentration of 25-hydroxyvitamin D3 [25(OH)D3]. Type 2 diabetes prevalence was ascertained by medical history, fasting plasma glucose concentrations, oral glucose tolerance testing and/or glycosylated hemoglobin. Men displayed higher crude or seasonally adjusted 25(OH)D3 serum concentrations than women (24.64 ± 10.98 vs. 22.88 ± 11.6 ng/ml; P < 0.001). Strong associations between body mass index (BMI) and 25(OH)D3 were observed in both genders (P < 0.001). Seasonally adjusted levels of 25(OH)D3 revealed stronger associations with type 2 diabetes in women than men (P < 0.001). However, adjustment for BMI and other confounding variables revealed an independent inverse association of 25(OH)D3 with diabetes only in women (P < 0.001), whereas the association was abrogated in men. Using a 15 ng/ml 25(OH)D3 cutoff for binary comparison, adjusted odds ratios for having newly diagnosed or known type 2 diabetes more than doubled (2.95 [95 % CI 1.37-4.89] and 3.26 [1.59-6.68], respectively), in women below the cutoff. We conclude that in women, but not in men, low 25(OH)D3 serum levels are independently associated with type 2 diabetes. These findings suggest sex-specific effects of Vit D in the pathogenesis of type 2 diabetes.

Gender- and site-specific differences of colorectal neoplasia relate to vitamin D

BACKGROUND

The effect of vitamin D on colorectal adenomas may vary with regard to gender, localisation and histological type of the lesion.

AIM

To define the role of vitamin D and gender in a Caucasian cohort of subjects undergoing screening colonoscopy after consideration of established risk factors.

METHODS

One thousand five hundred and thirty-two subjects (813 males, 58.8 ± 9.7 years; 719 females, 59.7 ± 10.7 years) were allocated to tertiles of 25-hydroxyvitamin D3 [25(OH)D3 ] serum concentrations. The number, localisation, size and histology of the detected colonic lesions were recorded.

RESULTS

Among men, no association was found between vitamin D and the total number, size and histological stage of adenomas at any site. In female subjects, less women with adenomas were found in the highest vitamin D tertile (N = 42/239; 17.2%) as compared to the low vitamin D group (N = 60/240; 25.0%; P = 0.035). In particular, the number of women with adenomas in the proximal colon was significantly lower in the highest tertile (N = 21/239, 8.8%) compared to the low vitamin D group (N = 41/240; 17.1%; P = 0.007). The rates at other sites were not different. The inverse association of vitamin D serum concentrations with the presence of adenomas in the proximal colon was maintained after adjustment for potential confounders. In 80 women on vitamin D supplementation, the rate of adenomas was lower compared to those not on supplementation (3/80; 3.8%; vs. 90/719; 12.5%; P = 0.016).

CONCLUSIONS

A potential preventive effect of vitamin D on colorectal adenomas was found in the proximal colon in women. This observation is supported by further decrease of lesions in the proximal colon of women on vitamin D supplementation.

Triple negative breast cancers express receptors for LHRH and are potential therapeutic targets for cytotoxic LHRH-analogs, AEZS 108 and AEZS 125

BACKGROUND

Triple negative breast cancer (TNBC) is a distinct subtype of breast cancer burdened with a dismal prognosis due to the lack of effective therapeutic agents. Receptors for LHRH (luteinizing hormone-releasing hormone) can be successfully targeted with AEZS-108 [AN-152], an analog of LHRH conjugated to doxorubicin. Our study evaluates the presence of this target LHRH receptor in human specimens of TNBC and investigates the efficacy and toxicity of AEZS-108 in vivo. We also studied in vitro activity of AEZS-125, a new LHRH analog conjugated with the highly potent natural compound, Disorazol Z.

METHODS

69 human surgical specimens of TNBC were investigated for LHRH-R expression by immunohistochemistry. Expression of LHRH-R in two TNBC cell lines was evaluated by real time RT-PCR. Cytotoxicity of AEZS-125 was evaluated by Cell Titer Blue cytoxicity assay. LHRH- receptor expression was silenced with an siRNA in both cell lines. For the in vivo experiments an athymic nude mice model xenotransplanted with the cell lines, MDA-MB-231 and HCC 1806, was used. The animals were randomised to three groups receiving solvent only (d 1, 7, 14, i.v.) for control, AEZS-108 (d 1, 7, 14, i.v.) or doxorubicin at an equimolar dose (d 1, 7, 14, i.v.).

RESULTS

In human clinical specimens of TNBC, expression of the LHRH-receptor was present in 49% (n = 69).HCC 1806 and MDA-MB-231 TNBC cells expressed mRNA for the LHRH-receptor. Silencing of the LHRH-receptor significantly decreased the cytotoxic effect of AEZS-108. MDA-MB-231 and HCC 1806 tumors xenografted into nude mice were significantly inhibited by treatment with AEZS-108; doxorubicin at equimolar doses was ineffective.As compared to AEZS 108, the Disorazol Z - LHRH conjugate, AEZS-125, demonstrated an increased cytotoxicity in vitro in HCC 1806 and MDA-MB-231 TNBC; this was diminished by receptor blockade with synthetic LHRH agonist (triptorelin) pretreatment.

CONCLUSION

The current study confirms that LHRH-receptors are expressed by a significant proportion of TNBC and can be successfully used as homing sites for cytotoxic analogs of LHRH, such as AEZS-108 and AEZS-125.

Targeted therapy in advanced metastatic colorectal cancer: Current concepts and perspectives

The introduction of new cytotoxic substances as well as agents that target vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) signaling has improved clinical outcome of patients with metastatic colorectal cancer (mCRC). In this review we summarize the most relevant clinical data on VEGF and EGFR targeting regimens in mCRC. The effects of available treatment strategies for mCRC are often temporary, with resistance and disease progression developing in most patients. Thus, new treatment strategies are urgently needed. Some GI peptides including gastrin and gastrin releasing peptide, certain growth factors such as insulin-like growth factor-I and II and neuropeptides such as growth hormone releasing hormone (GHRH) are implicated in the growth of CRC. Experimental investigations in CRC with antagonistic analogs of bombesin/gastrin-releasing peptide, GHRH, and with cytotoxic peptides that can be targeted to peptide receptors on tumors, are summarized in the second part of the review.

Systemic effect of catumaxomab in a patient with metastasized colorectal cancer: a case report

BACKGROUND

Catumaxomab, the first anti-EpCAM antibody, was approved in 2009 for the treatment of malignant ascites in cancer patients with EpCAM positive tumors. We consider this case of interest as treatment with catumaxomab not only prolonged the puncture-free interval but also showed a systemic effect in a patient with metastasized colorectal cancer by regression of a pulmonary metastasis.

CASE PRESENTATION

We describe the case of a 78 year old patient initially diagnosed with locally advanced colon cancer and one synchronous liver metastasis in September 2010 who was treated by hemicolectomy and simultaneous atypical liver resection. During adjuvant chemotherapy the patient developed a peritoneal carcinomatosis with ascites in March 2011. Palliative chemotherapy was not well tolerated and therefore refused by the patient. Because of disease progression in June 2011 with one pulmonary metastasis and clinically predominant ascites an immunotherapy with intraperitoneal catumaxomab was started in December 2011. After treatment with catumaxomab a puncture free survival of 12 months as well as a regression of the pulmonary lesion was achieved until January 2013.

CONCLUSION

This case suggests that treatment with catumaxomab does not only improve quality of life by local suppression of malignant ascites but also might have a systemic antitumor effect.

Female gender may predict response to FOLFIRINOX in patients with unresectable pancreatic cancer: a single institution retrospective review

FOLFIRINOX is a highly active regimen for the treatment of patients with unresectable pancreatic cancer. However, treatment with FOLFIRINOX is associated with relevant toxicity and predictors for response to therapy are warranted. We retrospectively analyzed 49 patients with unresectable pancreatic cancer treated with FOLFIRINOX in order to evaluate a possible predictive role of clinical parameters and tumor characteristics for response to chemotherapy. Tumor samples were characterized histopathologically before treatment and expression of p53 and Ki67 was analyzed using automated immunohistochemistry. Overall survival (OS) and progression-free survival (PFS) were estimated by the Kaplan-Meier method. The overall objective response rate was 55.1%, the disease control rate was 70.6%. Female gender was associated with a significantly higher disease control rate of 91.7 compared to 48.0% in male patients (p=0.001) which reached 100% in female patients when primarily treated compared to treatment after surgical resection and relapse (77.8%, p=0.057). For all patients median PFS was 3.5 months (95% CI, 2.7-4.3 months) and median OS was 13 months (95% CI, 9.4-16.6 months). Female patients showed a tendency towards a longer median PFS (5.0 months, 95% CI, 3.6-6.4 months) compared to males (3.0 months, 95% CI, 2.4-3.6 months) (p=0.099). Serum levels of CA19.9 and CEA were significantly higher in female patients compared to male patients (p=0.037, p=0.05). Tumors of patients with response to FOLFIRINOX showed a higher expression level of p53 and Ki67 as well as higher serum levels of CA19.9 compared to non-responders, which was statistically not significant. Our study indicates that female gender is a positive predictor for therapy response to FOLFIRINOX in patients with unresectable pancreatic cancer. Female gender in turn was associated with increased levels of tumor markers CEA and CA19.9 and patients with higher serum levels of CA19.9 were more responsive to FOLFIRINOX.

Combination of GHRH antagonists and docetaxel shows experimental effectiveness for the treatment of triple-negative breast cancers

In preclinical studies, antagonists of growth hormone-releasing hormone (GHRH) have demonstrated inhibitory effects on the growth of various types of cancers expressing the pituitary type of GHRH receptors (pGHRH-R) and/or its active splice variant 1 (SV1). In this study, we investigated the effectiveness of the treatment of MDA-MB-231 human triple-negative breast cancer (TNBC) with GHRH antagonist JMR-132 alone or in combination with docetaxel. Receptor expression in the MDA-MB-231 human breast cancer cell line was evaluated by reverse transcription-polymerase chain reaction (RT-PCR). Cell viability assays were performed on MDA-MB-231 cells treated with JMR-132, docetaxel or in combination. For studies in vivo, a subcutaneous nude mouse xenograft model was used. JMR-132 was administered s.c. at a dose of 10 µg/day and docetaxel at a dose of 10 mg/kg i.p. given on day 1 and 5. Similar regimens were used for the combination of both substances. At the end of the experiment, an mRNA-based human cancer pathway array including 84 major genes was performed on the tumor tissue of mice treated with JMR-132 to elucidate the mechanism of action of GHRH antagonists in vivo. The in vitro proliferation studies revealed that JMR-132 and docetaxel decreased the cell viability in a dose-dependent manner. The combination of both treatments produced a significantly greater inhibition of cell viability compared to the single agents. Treatment of nude mice bearing MDA-MB-231 xenografts with JMR-132 and docetaxel significantly (p<0.05) inhibited tumor growth by 46 and 50%, respectively. Treatment with the combination of JMR-132 and docetaxel led to an inhibition of tumor volume by 71.6% (p<0.001). Polymerase chain reaction array analysis revealed that JMR-132 interacts with signal transduction pathways involved in proliferation, apoptosis and angiogenesis. Our results suggest that GHRH antagonists in combination with taxanes may enhance the efficacy of treatment for patients with TNBC expressing the SV1 and/or the pGHRH receptor.

GHRH antagonist when combined with cytotoxic agents induces S-phase arrest and additive growth inhibition of human colon cancer

Treatment of colon cancer with an antagonist of growth hormone-releasing hormone (GHRH), JMR-132, results in a cell cycle arrest in S-phase of the tumor cells. Thus, we investigated the effect of JMR-132 in combination with S-phase-specific cytotoxic agents, 5-FU, irinotecan and cisplatin on the in vitro and in vivo growth of HT-29, HCT-116 and HCT-15 human colon cancer cell lines. In vitro, every compound inhibited proliferation of HCT-116 cells in a dose-dependent manner. Treatment with JMR-132 (5 μM) combined with 5-FU (1.25 μM), irinotecan (1.25 μM) or cisplatin (1.25 μM) resulted in an additive growth inhibition of HCT-116 cells in vitro as shown by MTS assay. Cell cycle analyses revealed that treatment of HCT-116 cells with JMR-132 was accompanied by a cell cycle arrest in S-phase. Combination treatment using JMR-132 plus a cytotoxic drug led to a significant increase of the sub-G 1 fraction, suggesting apoptosis. In vivo, daily treatment with GHRH antagonist JMR-132 decreased the tumor volume by 40-55% (p < 0.001) of HT-29, HCT-116 and HCT-15 tumors xenografted into athymic nude mice. Combined treatment with JMR-132 plus chemotherapeutic agents 5-FU, irinotecan or cisplatin resulted in an additive tumor growth suppression of HT-29, HCT-116 and HCT-15 xenografts to 56-85%. Our observations indicate that JMR-132 enhances the antiproliferative effect of S-phase-specific cytotoxic drugs by causing accumulation of tumor cells in S-phase.

Combination of gastrin-releasing peptide antagonist with cytotoxic agents produces synergistic inhibition of growth of human experimental colon cancers

We investigated the efficacy of a powerful antagonist of bombesin/gastrin-releasing peptide (BN/GRP) RC-3940-II administered as a single agent or in combination with cytotoxic agents on the growth of HT-29, HCT-116 and HCT-15 human colon cancer in vitro and in vivo. GRP-receptor mRNA and protein were found in all three cell lines tested. Exposure of HT-29 cells to 10 μM RC-3940-II led to an increase in the number of cells blocked in S phase and G 2/M and cells with lower G(0)/G(1) DNA content. Similar changes on the cell cycle traverse of HT-29 cells could also be seen at lower concentrations of RC-3940-II (1 μM) after pretreatment with 100 nM GRP (14-27), indicating a dose-dependent mechanism of action based on the blockage of BN/GRP induced proliferation of tumor cells at lower concentrations. Daily in vivo treatment with BN/GRP antagonist RC-3940-II decreased the volume of HT-29, HCT-116 and HCT-15 tumors xenografted into athymic nude mice by 25 to 67% (p < 0.005). Combined treatment with RC-3940-II and chemotherapeutic agents 5-FU and irinotecan resulted in a synergistic tumor growth suppression of HT-29, HCT-116 and HCT-15 xenografts by 43% to 78%. In HT-29 and HCT-116 xenografts the inhibition for the combinations of RC-3940-II and irinotecan vs. single substances (p < 0.05) was significantly greater. These findings support the use of RC-3940-II as an anticancer agent and may help to design clinical trials using RC-3940-II in combinations with cytotoxic agents.

Nonalcoholic fatty liver disease: an independent risk factor for colorectal neoplasia

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of insulin resistance (IR), and IR is associated with an increased risk of colorectal carcinoma (CRC). Increased echogenicity suggesting NAFLD is a frequent incidental finding on ultrasound examination. We aimed to systematically evaluate whether NAFLD is an independent risk factor for colonic neoplasia.

PATIENTS AND METHODS

One thousand two hundred and eleven patients (603 males, 60.6 ± 9.6 years; 608 females, 61.1 ± 10.3 years) who underwent screening colonoscopy according to national screening recommendations for CRC were evaluated in a cross-sectional study. Colorectal adenomas were classified as tubular adenoma, advanced adenoma (villous features, size ≥ 1 cm or high-grade dysplasia) or carcinoma. NAFLD was diagnosed by increased echogenicity on ultrasound examination after serological exclusion of infectious, immunological, hereditary or alcoholic aetiology.

RESULTS

Nonalcoholic fatty liver disease was diagnosed in 367 (60.8%) males and in 265 (43.5%) females. The total rate of adenomas was increased in subjects with NAFLD (243/367 vs. 107/236 in males, P = 0.010; 94/265 vs. 78/343 in females; P = 0.014). In particular, more tubular adenomas (127/367 vs. 56/236; P = 0.006), adenomas of the rectum (40/367 vs. 8/236; P = 0.004) and more cancers (6/367 vs. 1/236; P < 0.001) were observed in males with NAFLD. In females with NAFLD, more tubular adenomas (59/265 vs. 48/343; P = 0.011) and adenomas of the proximal colon (51/265 vs. 40/343; P = 0.041) were observed. Multivariate regression analyses demonstrated an independent association of colorectal adenomas with hepatic steatosis after adjustment for age, sex, body mass index and glucose intolerance (OR 1.47; 95% CI 1.079-2.003; P = 0.015).

CONCLUSION

Patients with NAFLD undergoing screening colonoscopy reveal significantly more CRC precursor lesions and early CRC compared with subjects without NAFLD. This elevated risk is independent from other manifestations of IR. These findings suggest that detecting fatty liver on ultrasound should heighten the awareness for referral to screening colonoscopy.

A correlation of endocrine and anticancer effects of some antagonists of GHRH

GHRH receptor antagonists inhibit growth and metastasis of a large number of experimental tumors expressing the pituitary GHRH receptor (pGHRH-R) and its major splice variant SV1. In this study, using Western blot, we demonstrated that DBTRG-05 and U-87MG human glioblastoma cell lines express pGHRH-R at levels 6-15 times higher than SV1. To reveal a correlation between the anticancer activity and the endocrine potency on inhibition of GH release, we compared the antitumor effect of GHRH antagonists JV-1-63 and MZJ-7-138 on growth of DBTRG-05 human glioblastomas grafted into athymic nude mice with their inhibitory potency on GH release. JV-1-63 strongly suppressed the stimulated GH secretion induced by clonidine in rats and inhibited the exogenous GHRH-induced GH surge by 88-99% in vivo and in vitro. MZJ-7-138 decreased the stimulated GH secretion by 58% in vitro and showed only a tendency to inhibit GH secretion in vivo. The strong inhibitor of GH release JV-1-63 reduced tumor growth of DBTRG-05 glioblastomas in nude mice by 46%, while the weak GH release suppressor MZJ-7-138 did not have an effect. Exposure of DBTRG-05 cells to the GHRH antagonists in vitro caused an upregulation of mRNA expression for pGHRH-R and a downregulation of SV1 expression, with JV-1-63 having significantly greater effects than MZJ-7-138. Our results demonstrate that a positive correlation exists between the endocrine potency and the antiproliferative efficacy of GHRH antagonists in tumors strongly expressing pGHRH-R.

A role for low hepatic copper concentrations in nonalcoholic Fatty liver disease

OBJECTIVES

Copper has a role in antioxidant defense, lipid peroxidation, and mitochondrial function, and copper deficiency has been linked to atherogenic dyslipidemia. We aimed to investigate the potential role of copper availability in the pathogenesis of nonalcoholic fatty liver disease (NAFLD).

METHODS

Patients with NAFLD (n=124) were compared to patients with chronic hepatitis C (n=50), hemochromatosis (n=35), alcoholic liver disease (n=13), autoimmune hepatitis (n=11), and control subjects (n=27). We determined liver and serum copper concentrations with correlation to clinical, histological, and biochemical parameters in humans. The effect of dietary copper restriction on liver histology and intermediary metabolism in rats was investigated.

RESULTS

Hepatic copper concentrations in patients with NAFLD were lower than in control subjects (17.9+/-8.4 vs. 31.4+/-8.2 microg/g; P<0.001) and in patients with other liver diseases (P<0.05 for all liver diseases). In patients with NAFLD, lower liver copper was correlated with more pronounced hepatic steatosis (R=-0.248; P=0.010), fasting glucose (R=-0.245; P=0.008), and components of the metabolic syndrome (MetS; R=0.363; P<0.001). Patients with nonalcoholic steatohepatitis (NASH; n=31) had lower hepatic copper concentrations than those with simple steatosis (n=93; P=0.038). Restriction of dietary copper in rats induced hepatic steatosis and insulin resistance (IR).

CONCLUSIONS

Reduced hepatic copper concentrations are found in human NAFLD and are associated with more pronounced hepatic steatosis, NASH, and components of the MetS. The development of hepatic steatosis and IR in response to dietary copper restriction in rats suggests that copper availability may be involved in the development of NAFLD.

Targeting gastrin releasing peptide receptors: New options for the therapy and diagnosis of cancer

Gastrin-releasing peptide (GRP), the mammalian bombesin (BN), appears to be involved in the growth of several neoplasms. BN/GRP receptors (BN/GRP-Rs) are expressed in a variety of cancer cells and have limited distribution in normal human tissue. Thus inhibition of BN/GRP-Rs represents an attractive target for pharmacological treatment of some human malignancies. This review will focus on intracellular signaling pathways which have been characterized to mediate BN/GRP-dependent receptor biological effects as well as on various approaches to target BN/GRP-Rs for therapeutic and diagnostic interventions in human malignancies.

Targeted cytotoxic somatostatin analog AN-162 inhibits growth of human colon carcinomas and increases sensitivity of doxorubicin resistant murine leukemia cells

The effect of the targeted cytotoxic somatostatin (SST) analog AN-162, consisting of doxorubicin (DOX) conjugated to SST carrier RC-121, was investigated on the growth of human colorectal cancer (CRC) cell lines HT-29, HCT-15, and HCT-116 and a DOX-resistant mouse leukemia cell line P388/R84. mRNA for SST-receptors and high affinity binding sites for SST were detected in all CRC cell lines and in P388/R84 cells. In contrast to DOX alone, AN-162 blocked HCT-116 cells and P388/R84 cells in S/G2 phase and increased the number of apoptotic cells. In vivo, AN-162 reduced the volume of CRC xenografts more effectively than its unconjugated components. Our results suggest that AN-162 inhibits growth of experimental CRC more effectively than DOX and increases sensitivity of DOX resistant human leukemia cells.

Iron stores, liver transaminase levels and metabolic risk in healthy teenagers

BACKGROUND

Iron overload may contribute to the pathogenesis of insulin resistance. We aimed to investigate the relationship among iron stores, liver transaminases and components of the metabolic syndrome in healthy teenagers in a cross-sectional study.

MATERIAL AND METHODS

We determined body mass index (BMI), waist-to-hip-ratio (WHR), blood pressure, liver ultrasound, serum lipids, insulin, fasting glucose, liver transaminase levels, hsCRP, iron parameters in 325 of 341 (95.3%) students (234 men, 16.7 +/- 1.7 years; 91 women, 16.5 +/- 1.7 years) of one single high school. Male and female study participants were allocated to increasing quartiles of body iron stores as assessed by sTfr/ferritin and alanine aminotranspeptidase (ALT) levels, and the distribution of cardiometabolic risk factors along quartiles was analysed. Regression analysis was performed to confirm the independent relationship between parameters.

RESULTS

In male students, BMI, WHR, systolic and diastolic blood pressure, serum triglyceride levels and hsCRP were higher in the top sTfR/ferritin and ALT quartiles compared with the lowest quartiles (P < 0.01 for all parameters). In female students, sTfR/ferritin were not associated with antropomorphic cardiometabolic risk factors but with insulin resistance (HOMA-IR, P = 0.046). Moreover, ALT levels were independently related to BMI, waist and hip circumference, systolic blood pressure, serum triglyceride and insulin concentrations (P < 0.05 for all parameters) in female students.

CONCLUSION

These results provide evidence for linkage among body iron stores, transaminase activity and the prevalence of cardiometabolic risk factors in apparently healthy, non-obese adolescents even within the range of normal laboratory and anthropomorphic values and suggest that iron stores should be investigated as a potentially modifiable risk factor in healthy teenagers.

Triple-negative breast cancers express receptors for luteinizing hormone-releasing hormone (LHRH) and respond to LHRH antagonist cetrorelix with growth inhibition

The aim of the present study was to evaluate the expression of receptors for luteinizing hormone-releasing hormone (LHRH) in human specimens of triple-negative breast cancers (TNBC). In addition, we used in vitro and in vivo models of TNBC to investigate if these receptors are suitable targets for the treatment with the LHRH antagonist cetrorelix. Receptors for LHRH were expressed in all tumor samples and in the TNBC cell lines HCC1806 and HCC1937. The proliferation of both TNBC cell lines was significantly inhibited in vitro by 1 microM cetrorelix. Injections of 3 mg cetrorelix on day 1 and 21 resulted in a significant growth inhibition of HCC1806 tumors xenografted into nude mice. Tumors of mice treated with cetrorelix expressed less mRNA for EGFR and HER3 receptors than untreated tumors. After treatment of cells with Cetrorelix a flow cytometric analysis of the cell cycle revealed a decrease in S-phase. Given the low toxicity and clinical availability of cetrorelix, this peptide antagonist should be considered for phase II studies in patients with advanced TNBC.

GHRH antagonist causes DNA damage leading to p21 mediated cell cycle arrest and apoptosis in human colon cancer cells

We investigated the mechanisms of inhibitory effect of growth hormone-releasing hormone (GHRH) antagonist JMR-132 on the growth of HT29, HCT-116 and HCT-15 human colon cancer cells in vitro and in vivo. High-affinity binding sites for GHRH and mRNA for GHRH and splice variant-1 (SV1) of the GHRH receptor were found in all three cell lines tested. Proliferation of HT-29, HCT-116 and HCT-15 cells was significantly inhibited in vitro by JMR-132. Time course studies revealed that the treatment of human HCT-116 colon cancer cells with 10 muM GHRH antagonist JMR-132 causes a significant DNA damage as shown by an increase in olive tail moment (OTM) and loss of inner mitochondrial membrane potential (Delta Psi m). Western blotting demonstrated a time-dependent increase in protein levels of phospho-p53 (Ser46), Bax, cleaved caspase-9, -3, cleavage of poly(ADP-ribose)polymerase (PARP) and a decrease in Bcl-2 levels. An augmentation in cell cycle checkpoint protein p21(Waf1/Cip1) was accompanied by a cell cycle arrest in S-phase. DNA fragmentation visualized by the comet assay and the number of apoptotic cells increased time dependently as determined by flow cytometric annexinV and PI staining assays. In vivo, JMR-132 decreased the volume of HT-29, HCT-116 and HCT-15 tumors xenografted into athymic mice up to 75% (p < 0.05) and extended tumor doubling time (p < 0.001). Our observations suggest that GHRH antagonist JMR-132 exerts its antiproliferative effect on experimental colon cancer cells through p21(Waf1/Cip1) mediated S-phase arrest along with apoptosis involving the intrinsic pathway.

Effective treatment of triple-negative breast cancer with targeted cytotoxic somatostatin analogue AN-162 (AEZS-124)

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Background: Triple negative breast cancers (TNBC) represent a distinct subtype of breast cancer being negative to ER, PR and HER2 and are associated with poor prognosis. Limited systemic treatment options exist for TNBC. TNBC cells express somatostatin receptors (SSTR). Therefore, to investigate preclinical characteristics of TNBC we used a novel targeted cytotoxic somatostatin analogue AN-162 containing doxorubicin (DOX) which binds to the subtypes 2, 3 and 5 of SSTR. Methods: The expression of SSTR in HCC 1806 human TNBC cell line was detected by RT-PCR. Cytotoxic effect of AN-162 in vitro was visualized by ethidium bromide staining fluorescence microscopy. Internalization of AN-162 into HCC 1806 cells was tested by 125Iodide-labeled AN-162 uptake assays and the presence of DOX in the nucleus was measured by fluorescence assays after separating the nucleus from the cytoplasm. For in vivo experiments, HCC 1806 TNBC cells were xenografted subcutaneously into nude mice which were then randomized into four groups receiving AN-162, DOX, an unconjugated mixture of DOX and somatostatin analogue RC-160 at the same equimolar dose of 2.5 μmol/kg (1.45 mg/kg Dox equivalent) i.v. (q7d 4x) and vehicle solution control. Results: HCC 1806 TNBC cell line was positive for the expression of all five SSTR receptor subtypes. Ethidum bromide staining of cells treated with 2.5 μM of AN-162 for 30 min demonstrated cell death after 24h by fluorescence microscopy. Uptake assays with AN-162 showed specific internalization of AN-162 into the cells mediated through the sstrs. After treatment of the cells with 2.5 μM AN-162 for 10 or 30 min, DOX could be detected in the nucleus by fluorescence assays. In vivo, AN-162 significantly (p<0.05) inhibited tumor growth of HCC 1806 xenografts compared to Control, DOX and the unconjugated mixture of DOX+RC-160 from day 14 and the inhibition remained significant until the end of the study on day 35. Conclusions: Our results indicate that treatment with targeted cytotoxic somatostatin analogue AN-162 produces a greater inhibition of tumor growth than DOX alone in somatostatin receptor positive TNBC. Our findings support the concept of targeted chemotherapy based on cytotoxic peptide analogues for the treatment of breast cancer and other cancers.

No significant financial relationships to disclose.

Retinol-binding protein 4 in polycystic ovary syndrome--association with steroid hormones and response to pioglitazone treatment

CONTEXT

Polycystic ovary syndrome (PCOS) is frequently associated with insulin resistance.

OBJECTIVE

The aim of the study was to investigate a putative role of the adipokines retinol-binding protein 4 (RBP4), adiponectin, and visfatin in a cohort of patients with PCOS and their response to treatment with pioglitazone.

DESIGN AND SETTING

We conducted a randomized, controlled, double-blind study at a tertiary referral center.

PATIENTS AND INTERVENTIONS

Forty premenopausal women with PCOS were allocated to receive treatment with either pioglitazone (30 mg/d) or a placebo for a period of 3 months.

MAIN OUTCOME MEASURES

Serum concentrations of RBP4, adiponectin, and visfatin were determined along with metabolic and hormonal parameters before and after treatment.

RESULTS

Serum adiponectin concentrations were higher after treatment with pioglitazone (P = 0.003), whereas RBP4 levels tended to decrease (P = 0.06), and visfatin concentrations remained unchanged. We found RBP4 serum concentrations at baseline to be positively correlated with serum levels of testosterone (R = 0.446; P = 0.005), 17-OH progesterone (R = 0.345, P = 0.037), and dehydroepiandrosterone sulfate (R = 0.347; P = 0.041). However, these correlations were abolished after treatment with pioglitazone. Patients with high RBP4 levels had significantly higher hirsutism scores (P = 0.038 before and P = 0.034 after treatment). In contrast, serum adiponectin concentrations were related to parameters of impaired glucose metabolism, and no significant associations were detected for visfatin.

CONCLUSIONS

Our results suggest that RBP4 may contribute to endocrine changes and to the phenotypic manifestation of patients with PCOS because higher RBP4 concentrations are associated with higher androgen levels and higher clinical hirsutism scores independently of pioglitazone treatment. The molecular involvement of RBP4 in human steroid metabolism requires further clarification.

Dose-dependent growth inhibition in vivo of PC-3 prostate cancer with a reduction in tumoral growth factors after therapy with GHRH antagonist MZ-J-7-138

BACKGROUND

Antagonists of growth hormone-releasing hormone (GHRH) inhibit the growth of various cancers and affect tumoral growth factors.

METHODS

We investigated the effect of a new GHRH antagonist MZ-J-7-138 at doses of 1.25, 2.5, 5 and 10 microg/day s.c. on the growth of PC-3 human androgen independent prostate cancers xenografted s.c. into nude mice. Binding assays were used to investigate GHRH receptors. The levels of IGF-II and VEGF in tumors were measured by radioimmunoassays.

RESULTS

Treatment with 2.5, 5, and 10 microg/day MZ-J-7-138 caused a significant dose-dependent growth reduction of PC-3 tumors. The greatest inhibition of 78% was obtained with 10 microg/day. The suppression of IGF-II protein levels in tumors was seen at all doses of MZ-J-7-138, but only 10 microg dose induced a significant inhibition. MZ-J-7-138 also reduced VEGF protein levels, the inhibition being significant at doses of 5 and 10 microg. Specific high affinity binding sites for GHRH were found on PC-3 tumors using (125)I-labeled GHRH antagonist JV-1-42. MZ-J-7-138 displaced radiolabeled JV-1-42 with an IC(50) of 0.32 nM indicating its high affinity to GHRH receptors. Real-time PCR analyses detected splice variant 1 (SV1) of GHRH receptor (GHRH-R) as well as pituitary type of GHRH-R and GHRH ligand.

CONCLUSION

Our results demonstrate the efficacy of GHRH antagonist MZ-J-7-138 in suppressing growth of PC-3 prostate cancer at doses lower than previous antagonists. The reduction of levels of growth factors such as VEGF and IGF-II in tumors by GHRH antagonist was correlated with the suppression of tumor growth.

Inhibition of estrogen receptor positive and negative breast cancer cell lines with a growth hormone-releasing hormone antagonist

GHRH antagonists have been shown to inhibit growth of various human cancer cell lines xenografted into nude mice including estrogen receptor negative human breast cancers. Previous observations also suggest that GHRH locally produced in diverse neoplasms including breast cancer might directly affect proliferation of tumor cells. In the present study we demonstrate that a novel highly potent GHRH antagonist JMR-132 strongly inhibits the proliferation of both estrogen receptor negative SKBR 3 and estrogen receptor positive ZR 75 human breast cancer cell lines in vitro. The proliferation in vitro of ZR 75 and SKBR 3 was increased after direct stimulation with GHRH(1-29)NH2. The GHRH antagonist JMR-132 had a significant antiproliferative activity in the absence of GHRH and nullified the proliferative effect of GHRH in these cell lines. SKBR 3 and ZR 75 expressed the GHRH ligand as well as the pituitary type of GHRH-receptor, which likely appears to mediate the antiproliferative mechanisms in these cell lines. These in vitro results suggest that JMR-132 is a potent inhibitor of breast cancer growth, independent of the estrogen receptor status. Further investigations on the combination treatment with endocrine agents affecting the estrogen pathway and GRHR antagonists are needed in order to improve the treatment of breast cancer.

Copper availability contributes to iron perturbations in human nonalcoholic fatty liver disease

BACKGROUND & AIMS

Iron perturbations are frequently observed in nonalcoholic fatty liver disease (NAFLD). We aimed to investigate a potential association of copper status with disturbances of iron homeostasis in NAFLD.

METHODS

We retrospectively studied 140 NAFLD patients and 25 control subjects. Biochemical and hepatic iron and copper parameters were analyzed. Hepatic expression of iron regulatory molecules was investigated in liver biopsy specimens by reverse-transcription polymerase chain reaction and Western blot analysis.

RESULTS

NAFLD patients had lower hepatic copper concentrations than control subjects (21.9 +/- 9.8 vs 29.6 +/- 5.1 microg/g; P = .002). NAFLD patients with low serum and liver copper concentrations presented with higher serum ferritin levels (606.7 +/- 265.8 vs 224.2 +/- 176.0 mg/L; P < .001), increased prevalence of siderosis in liver biopsy specimens (36/46 vs 10/47 patients; P < .001), and with elevated hepatic iron concentrations (1184.4 +/- 842.7 vs 319.9 +/- 451.3 microg/g; P = .020). Lower serum concentrations of the copper-dependent ferroxidase ceruloplasmin (21.7 +/- 4.1 vs 30.4 +/- 6.4 mg/dL; P < .001) and decreased liver ferroportin (FP-1; P = .009) messenger RNA expression were found in these patients compared with NAFLD patients with high liver or serum copper concentrations. Accordingly, in rats, a reduced dietary copper intake was paralleled by a decreased hepatic FP-1 protein expression.

CONCLUSIONS

A significant proportion of NAFLD patients should be considered copper deficient. Our results indicate that copper status is linked to iron homeostasis in NAFLD, suggesting that low copper bioavailability causes increased hepatic iron stores via decreased FP-1 expression and ceruloplasmin ferroxidase activity thus blocking liver iron export in copper-deficient subjects.

Differential expression of GHRH receptor and its splice variant 1 in human normal and malignant mucosa of the oesophagus and colon

Recent evidence indicates that growth hormone-releasing hormone (GHRH) functions as a growth factor for gastrointestinal (GI) tumours. The tumourigenic effects of GHRH appear to be mediated by the splice variant 1 (SV-1) of GHRH receptor as well as the full length pituitary type receptor for GHRH (GHRH-R). We examined the protein and mRNA expression of GHRH-R and SV-1 in normal human tissues and tumours of the gastrointestinal (GI-) tract by immunohistochemical staining and reverse transcriptase (RT)-PCR. Squamous cells and squamous cell carcinoma of the oesophagus were negative for GHRH-R and SV-1, while Barrett's mucosa and adenocarcinomas of the oesophagus showed a strong expression of both receptors. The expression of GHRH-R was absent in normal colonic mucosa other than neuroendocrine cells (NE) and lining epithelium (LE) but strong in tubular adenomas of the colon, while the staining for SV-1 was absent in cells other than NE. However, the expression of both receptors was significantly increased in tubulovillous adenomas and colorectal cancers. No differences were seen in protein levels for both receptors between normal and neoplastic tissues of the stomach, pancreas and liver. Because of low mRNA levels for both receptors in all samples tested, only a qualitative assessment could be made. However, mRNA for GHRH-R and SV-1 showed a near-perfect correlation with the assessment of receptor proteins by immunostaining. Our study shows that in contrast to normal mucosa, transformed mucosa of the oesophagus and the colon expresses GHRH-R and SV-1. This aberrant expression of GHRH-R and SV-1 in oesophageal and colorectal malignancies may provide a molecular target for a therapeutic approach based on GHRH antagonists.

Contribution of anti-cyclic citrullinated peptide antibody and rheumatoid factor to the diagnosis of arthropathy in haemochromatosis

OBJECTIVE

To investigate the prevalence of antibodies to cyclic citrullinated peptide (anti-CCP) and rheumatoid factor in patients with hereditary haemochromatosis (HHC) and to evaluate their diagnostic reliability in distinguishing HHC-associated arthropathy from rheumatoid arthritis.

METHODS

Anti-CCP antibodies and rheumatoid factor levels were determined by ELISA in sera from 87 patients with HHC homozygous for the C282Y mutation of the HFE gene, 31 patients with rheumatoid arthritis and 162 healthy controls.

RESULTS

Of the 87 patients with HHC, 32 (36.8%) had joint involvement. Anti-CCP antibodies were detected in only 1 patient (1.1%) with HHC, who had no joint disease, and in (1.2%) healthy controls. In total, 18 (58.1%) patients with rheumatoid arthritis displayed anti-CCP reactivity (p<0.001). Rheumatoid factor was detected in 10 (11.5%) patients with HHC compared with 7 (4.3%) healthy control subjects (p = 0.03) and 21 of 31 (65.6%) patients with rheumatoid arthritis.

CONCLUSIONS

Testing for anti-CCP antibodies discriminates HHC arthropathy from rheumatoid arthritis, as these patients were consistently anti-CCP negative. Thus, HHC arthropathy should be considered in the differential diagnosis of CCP-negative arthritis.

Potentiation of mammary cancer inhibition by combination of antagonists of growth hormone-releasing hormone with docetaxel

Antagonists of growth hormone-releasing hormone (GHRH) are being developed for the treatment of various cancers. In this study, we investigated the effectiveness of treatment with GHRH antagonist JMR-132 alone and in combination with docetaxel chemotherapy in nude mice bearing MX-1 human breast cancers. Specific high-affinity binding sites for GHRH were found on MX-1 tumor membranes using ligand competition assays with (125)I-labeled GHRH antagonist JV-1-42. JMR-132 displaced radiolabeled JV-1-42 with an IC(50) of 0.14 nM, indicating a high affinity of JMR-132 to GHRH receptors. Treatment of nude mice bearing xenografts of MX-1 with JMR-132 at 10 microg per day s.c. for 22 days significantly (P < 0.05) inhibited tumor volume by 62.9% and tumor weight by 47.8%. Docetaxel given twice at a dose of 20 mg/kg i.p. significantly reduced tumor volume and weight by 74.1% and 58.6%, respectively. Combination treatment with JMR-132 (10 microg/day) and docetaxel (20 mg/kg i.p.) led to growth arrest of most tumors as shown by an inhibition of tumor volume and weight by 97.7% and 95.6%, respectively (P < 0.001). Because no vital cancer cells were detected in some of the excised tumors, a total regression of the tumors was achieved in some cases. Treatment with JMR-132 also strongly reduced the concentration of EGF receptors in MX-1 tumors. Our results demonstrate that GHRH antagonists might provide a therapy for breast cancer and could be combined with docetaxel chemotherapy to enhance the efficacy of treatment.

Synergistic inhibition of growth of lung carcinomas by antagonists of growth hormone-releasing hormone in combination with docetaxel

We investigated the effect of antagonists of growth hormone-releasing hormone (GHRH) MZ-J-7-138 and JV-1-92 on H460 human non-small cell lung carcinoma (NSCLC) xenografted orthotopically into nude mice. Treatment with MZ-J-7-138 or JV-1-92 inhibited orthotopic growth of H460 NSCLC by 52-65% (P < 0.001) and was associated with a significant decrease in protein expression of K-Ras, cyclooxygenase-2 (Cox-2) and phospho-Akt (pAkt). In other experiments, treatment with MZ-J-7-138 or docetaxel reduced tumor volume of s.c. xenografted H460 human NSCLC by 30-36% (P < 0.01). The combination of MZ-J-7-138 and docetaxel resulted in a synergistic growth inhibition of H460 NSCLC xenografts of 63%. MZ-J-7-138 alone or in combination with docetaxel significantly reduced protein levels of K-Ras, Cox-2, and pAkt by 56-63%. Docetaxel given singly diminished the protein levels only of Cox-2 and did not affect K-Ras and pAkt. High-affinity binding sites, mRNA, and protein expression of pituitary GHRH receptors and its splice variant (SV) 1 were found in H460. H460 NSCLC cells contained GHRH peptide, and its growth was significantly inhibited in vitro by 10 microM MZ-J-7-138 (P < 0.001). Serum insulin-like growth factor 1 (IGF1) was not reduced by either GHRH antagonists. These findings suggest that antiproliferative effects of GHRH antagonists in H460 NSCLC are associated with down-regulation of K-Ras, Cox-2, and pAkt. In conclusion, GHRH antagonists in combination with docetaxel synergistically inhibit growth of H460 NSCLC and the expression of K-ras, Cox-2, and pAkt, which might abrogate the signal transduction pathways for cell growth stimulation and therapeutic resistance.

Therapy of ovarian cancers with targeted cytotoxic analogs of bombesin, somatostatin, and luteinizing hormone-releasing hormone and their combinations

The aim of this study was to investigate the effect of treatment of experimental ovarian cancers with targeted cytotoxic analogs as single compounds and in combination. Targeted cytotoxic analogs of bombesin (AN-215), somatostatin (AN-238), and luteinizing hormone-releasing hormone (AN-207) consisted of 2-pyrrolinodoxorubicin (AN-201) linked to the respective peptide carrier. AN-238 at 200 nmol/kg significantly inhibited growth of UCI-107, ES-2 and OV-1063 ovarian cancers. AN-215 alone at 200 nmol/kg and its combination with AN-238 at one-half of the dose were also able to inhibit the growth of UCI-107 tumors. A combination of AN-238 with AN-207at 50% of the dose strongly suppressed the proliferation of ES-2 and OV-1063 ovarian tumors. Cytotoxic radical AN-201 was toxic and had no significant effect on tumor growth. In contrast, the toxicity of the conjugated peptide analogs was low. Because ovarian cancers tend to acquire chemoresistance, we used real-time PCR to measure the mRNA expression of multidrug resistance protein 1, multidrug resistance-related protein 1, and breast cancer resistance protein after treatment. Low or no induction of multidrug resistance protein 1, multidrug resistance-related protein, and breast cancer resistance protein occurred after treatment with AN-238, AN-215, and the combination of AN-238 with AN-207 or AN-215. These results demonstrate that a therapy with cytotoxic analogs such as single agents and combinations is effective and nontoxic. Our work suggests that cytotoxic peptide analogs of luteinizing hormone-releasing hormone, somatostatin, and bombesin could be used for the therapy of ovarian cancers, considering the lack of induction of chemoresistance.

Delayed addition of deoxycytidine protects normal CD34+ cells against cytotoxicity of gemcitabine without compromising its activity against human leukemic cells

In phase I and II clinical trials, the deoxycytidine analogue 2',2' difluorodeoxycytidine (dFdC, gemcitabine) has shown promising antitumor activity in leukemia as well as in solid tumors. Preclinical and clinical studies of gemcitabine suggested that myelosuppression was the dose-limiting toxicity. The present investigations were designed to test the effect of continuously administered gemcitabine on the in vitro clonal growth of normal CD34(+) cells isolated from peripheral blood and the promyelocytic cell line, HL-60. For this purpose, CD34(+) and HL-60 cells were cultured in methylcellulose in the continuous presence of 0.1-16 nM of gemcitabine. The results show a dose-dependent inhibition of colony growth of normal as well as leukemic cells. However, HL-60 cells were up to 12-fold more sensitive towards gemcitabine than normal progenitors. For rescue experiments, the natural pyrimidine deoxycytidine (dCyd) was added to CD34(+) and HL-60 cells simultaneously or with delay. Coadministration of 1mM dCyd to separate cultures resulted in complete restoration of colony formation capacity of CD34(+) and HL-60 cells. Delayed addition of 1 mM dCyd after 48 and 72 hours recovered up to 90% and 40%, respectively, of stem cell proliferation, whereas HL-60 cells remained substantially inhibited (4.5% +/- 3.5% versus 0%). Delayed addition after 48 and 72 hours protected about 80% and 50%, respectively, of myelopoietic and erythropoetic colony formation, whereas colony formation obtained from HL-60 cells remained significantly inhibited (9.6% +/- 4.17% versus 0%). These in vitro data suggest that there is a marked difference in the susceptibility of leukemic and normal CD34(+) cells to gemcitabine and that delayed administration of dCyd may further reduce the bone marrow cytotoxicity of gemcitabine without impairing its antitumor effect.

In vitro studies on the immunosuppressive effect of 2',2'-difluorodeoxycytidine (dFdC) and its metabolite 2',2'-difluorodeoxyuridine (dFdU)

The effect of 2',2'-difluorodeoxycytidine (dFdC) on in vitro human lymphocyte response was assessed in comparison with that of its major metabolite 2',2'-difluorodeoxyuridine (dFdU). Peripheral blood mononuclear cells (PBMNC) from healthy human volunteers were used for assay of mixed lymphocyte reaction (MLR), blastogenesis and colony forming by PHA. Both substances inhibited mitogen and alloantigen responses of PBMNC in a dose-dependent manner, but dFdU was up to 10,000-fold less potent than its parent compound dFdC. The data indicate that activation by alloantigen is more sensitive to the action of dFdU and dFdC than the response to PHA. Thus, dFdU inhibits MLR-induced response at significantly lower doses than PHA-induced proliferation (IC50 +/- SD, 23.55 +/- 8 microM versus 133.2 +/- 12 microM) (p = 0.0003). dFdC also proved to be about 12.3-fold more potent against alloantigen response compared to PHA-induced proliferation of PBMNC (IC50 +/- SD, 2.28 +/- 0.5 nM versus 28.1 +/- 0.5 nM) (p = 0.0001). To get an insight into the toxic profile of dFdU and dFdC, both substances were additionally tested on the in vitro clonal growth of CD34+ cells. Cells were cultured in methylcellulose in the continuous presence of dFdU and dFdC in doses up to 640 microM and 16 nM, respectively. The results show a marked inhibition of erythroid (BFU-E) and myeloid progenitors (CFU-GM) in a dose-dependent manner, but BFU-E was more sensitive to the action of dFdU and dFdC than CFU-GM (p=0.0001). Compared to T-lymphocytes, however, similar or even higher doses of dFdU and dFdC were required for complete inhibition of colony formation obtained from CD34+ cells. To test the role of deoxycytidine kinase (dCK) in the metabolism of dFdU in comparison to that of dFdC, reversal studies with deoxycytidine (dCyd), the natural substrate of dCK, were performed on dFdU- and dFdC-treated HL-60 cells. The data show that relatively low concentrations of dCyd (10 microM) were sufficient to protect HL-60 cells from cytotoxicity of lethal doses of dFdU (160 microM), whereas 100-fold higher concentrations of deoxycytidine (dCyd) (1 mM) were required for a complete reversal of dFdC-mediated toxicity. This suggests that activation of dFdU is due to its phosphorylation by dCK, but dFdU has low affinity to dCK. These effects of dFdU and dFdC in relation to T-lymphocytes and CD34+ cells suggest their possible use as immunosuppressive agents.