Superparamagnetic iron oxide nanoparticles for their application in the human body: Influence of the surface.

Iron oxide nanoparticles (IONs) are of great interest in nanomedicine for imaging, drug delivery, or for hyperthermia treatment. Although many research groups have focused on the synthesis and application of IONs in nanomedicine, little is known about the influence of the surface properties on the particles' behavior in the human body. This study analyzes the impact of surface coatings (dextran, polyvinyl alcohol, polylactide-co-glycolide) on the nanoparticles' cytocompatibility, agglomeration, degradation, and the resulting oxidative stress induced by the particle degradation. All particles, including bare IONs (BIONs), are highly cytocompatible (>70%) and show no significant toxicity towards smooth muscle cells. Small-angle X-ray scattering profiles visualize the aggregation behavior of nanoparticles and yield primary particle sizes of around 20 nm for the investigated nanoparticles. A combined experimental setup of dynamic light scattering and phenanthroline assay was used to analyze the long-term agglomeration and degradation profile of IONs in simulated body fluids, allowing fast screening of multiple candidates. All particles degraded in simulated endosomal and lysosomal fluid, confirming the pH-dependent dissolution. The degradation rate decreased with the shrinking size of particles leading to a plateau. The fastest Fe2+ release could be measured for the polyvinyl-coated IONs. The analytical setup is ideal for a quick preclinical study of IONs, giving often neglected yet crucial information about the behavior and toxicity of nanoparticles in the human body. Moreover, this study allows for the development and evaluation of novel ferroptosis-inducing agents.

Prognostic significance of methylated RASSF1A and PITX2 genes in blood- and bone marrow plasma of breast cancer patients.

Free circulating DNA is increased in the serum/plasma of cancer patients, and methylation of certain genes has been found to be characteristic for malignancy. Therefore, we investigated the prognostic value of two promising genes, PITX2 and RASSF1A, in peripheral blood-plasma (PB-P) and bone marrow plasma (BM-P) of breast cancer patients. Peripheral blood and bone marrow samples from patients with primary breast cancer were prospectively collected during primary surgery at the Department of Obstetrics and Gynecology in Innsbruck (n = 428) from June 2000 to December 2006. The study has been approved by the ethical committee of the Medical University of Innsbruck. Methylation analysis was performed using MethyLight, a methylation-specific quantitative PCR-method. In univariate survival analysis, methylated PITX2 in PB-P was found to be a significant indicator for poor overall survival (OAS) and distant disease-free survival (DDFS) (P = 0.001 and P = 0.023). Methylated RASSF1A in PB-P was also an indicator for poor OAS and DDFS (P = 0.001 and P = 0.004). RASSF1A had also significant prognostic potential when determined in BM-P (P = 0.016). In multivariate survival analysis methylated PITX2 and RASSF1A in PB-P remained as therapy-independent prognostic factors for OAS (P = 0.021, P < 0.001). For DDFS only RASSF1A in PB-P showed prognostic significance (P = 0.002). Methylated RASSF1A and PITX2 in PB-P appear to have promising potential as prognostic markers in clinical use.

The prognostic impact of bone marrow micrometastases in women with breast cancer.

Metastasis is the overwhelming cause of mortality in patients with breast cancer and our understanding of its cellular and molecular determinants is limited. Among cellular determinants, disseminated (DTC) tumor cells undoubtedly are key players in the metastatic cascade. In the past, several models have been constructed to explain the presence of individual tumor cells in secondary organs and their influence on the subsequent course of the disease. According to most recent transcriptome and genome analyses, DTCs are viewed as rare and much earlier indicators of metastasis than generally assumed from the typical course of breast cancer. Despite the observation that the numerous genetic alterations in such cells are rarely identical or even similar, characterization of the long interval between dissemination and clinically manifested metastases, the resistance to chemotherapy and significant effect on disease progression despite the low abundance in secondary organs, support the idea that some of these cells might be progenitor cells with self-renewing properties that give rise to most of the tumor mass that is dealt with clinically. Here, we review evidence from translational research and data from observational studies on DTCs to elucidate their potential impact for both future clinical trial design and, in the long run, decision-making in our daily patient management.

Expression of coxsackie-adenovirus receptor is related to estrogen sensitivity in breast cancer.

This study analyzes the relationship between coxsackie-adenovirus receptor (CAR) expression (transmembrane and soluble isoforms) and hormone sensitivity in 95 breast cancers. Furthermore, prognostic significance of the expression of the various CAR isoforms was investigated. In addition, inducibility of CAR expression by estradiol and tamoxifen was assessed in various breast cancer cell lines. Expression of transmembrane CAR (hCAR) highly correlated with estrogen receptivity, but was independent of the expression of progesterone receptor (PR). Furthermore, hCAR expression was significantly higher in tumors with low-grade malignancy. However, no relationship between hCAR expression and tumor size, lymph node status, or survival was revealed. In the hormone receptor-positive breast cancer cell line T47-D expression of hCAR and its soluble isoforms was increased by treatment with estradiol and tamoxifen. In contrast, no induction of either CAR isoform was achieved in receptor-negative cell lines. Furthermore, enhancement of hCAR expression was significantly greater when cells were treated with the histone deacetylase (HDAC) inhibitor trichostatin A (TSA) than when treated with estradiol or tamoxifen. Moreover, sensitivity to TSA induction of hCAR was considerably greater in receptor-positive than in receptor-negative cell lines. No additive effect on CAR expression was found when TSA was combined with either estradiol or tamoxifen. In conclusion, the so far undescribed association between estrogen receptivity and the expression of hCAR in breast cancer seems to not only reflect a phenotype of low malignancy, but expression of hCAR may also be directly influenced by ER-specific ligands.

The growth-promoting action of individual women's sera on mammary carcinoma cells.

In vitro studies concerning the growth-stimulating effect of hormones, especially of estradiol and its metabolites, have mainly been performed using pure substances and breast cancer cell lines. In order to take into account the metabolism of inactive into active hormones or drugs and vice versa which occurs in several tissues, the influence of individual patients' sera on the growth of breast cancer cells in vitro was tested. Besides measuring the growth promoting action of several hormone replacement therapies, the antiestrogenic effect was determined by measuring the effect of 10(-10) M estradiol added to the culture medium (E2-sensitivity). Influence on proliferation and stimulatability was similar in MCF-7 and T47-D cells. Growth-promoting potential correlated significantly with patient age, being higher in young ladies than in older ones. The converse was true for E2 sensitivity. From the different steroid hormones tested, only higher estradiol levels were associated with increased growth stimulation and diminished E2 sensitivity. Hormone replacement therapy (HRT) of different types did not significantly increase growth potential of serum, however these results are preliminary. Treatment with tamoxifen of breast cancer patients led to a decrease of E2 sensitivity, whereas growth potential was not affected significantly. For the aromatase inhibitor Arimidex, a tendency towards growth inhibition and increased E2 sensitivity was observed. Our in vitro system allows identifying differences between individual persons and groups of women of different age or treatment with respect to stimulation of growth or influence on estrogen sensitivity of breast cancer cells by serum. It is speculated that results might reflect the personal risk or the risk under treatment to develop breast cancer.

Disseminated tumor cells: are they ready for clinical use?

During the past three decades, efforts successfully established the presence of disseminated tumor cells (DTC) in bone marrow as a prognostic factor. These works were comprehensively evaluated in a pooled analysis that now permits to classify the prognostic significance of DTC as level I evidence. Intriguing molecular data suggest a role for tumor stem cells possibly responsible for the prognostic impact of DTC. In a typical clinical setting of the year 2007, DTC--irrespectively of the strong prognostic significance--would only have a convincing clinical application if DTC were a surrogate marker for treatment efficacy. Consequently, this important question is to be addressed in well-designed clinical trials.

Modulation of CA-125 tumor marker shedding in ovarian cancer cells by erlotinib or cetuximab.

OBJECTIVE: The EGF receptor tyrosine kinase inhibitor erlotinib and the EGF receptor antibody cetuximab were investigated with respect to their antiproliferative effect in vitro and their influence on the synthesis and secretion of the tumor marker CA-125 in ovarian carcinoma and human peritoneal mesothelial (HPMC) cells. METHODS: Ovarian cancer cell lines and HPMC were cultured in vitro under the usual conditions. CA-125 surface expression was detected by a living cell radio-immunoassay. CA-125 concentration shed into supernatant medium was determined using a microparticle enzyme immunoassay. RESULTS: Proliferation was inhibited by erlotinib in a dose-dependent manner in 4/5 cell lines but in none of the HPMCs. Only the erlotinib-sensitive cell lines also responded by decreasing surface density of CA-125. Release of CA-125 into the supernatant medium was independent of its surface density and was increased by erlotinib treatment in all but HTB77 cancer cells but not in HPMCs. Very similar results were obtained when the EGFR antibody cetuximab was used in place of erlotinib. CONCLUSION: The results indicate that the effects observed were a consequence of EGFR inhibition. The influence exerted by erlotinib or cetuximab treatment on shedding and cell surface density of CA-125 leads us to conclude that CA-125 blood levels measured during therapy might not correctly indicate changes in tumor size.