Antitumoral Activity of 3rd Generation Derivative Lobaplatin in In Vitro Models of Triple-Negative Breast Cancers

Introduction:Triple-negative breast cancers are characterized by aggressive growth and early metastasic spread. Some preliminary clinical data have demonstrated good anti-tumor activity of platinum derivatives. 3rd generation compound Lobaplatin* has shown a favorable toxicity profile as compared to Cisplatin. We therefore evaluated this compound in in vitro models of triple negative breast cancers.Study design:Triple-negative humane breast cancer cell lines HCC 1937 and HCC 1806 were treated with increasing concentrations of Lobaplatin and Cisplatin (0,16-10 μm). Cells were incubated for 24, 48 and 72 h with both substances in serum-free and serum-containing medium, in order to evaluate cytotoxic effects in proliferating as well as in metabolically inactive cells. Induction of apoptosis was tested by cleavage of PARP and Caspase 3 as demonstrated by western blot analysis. Subsequently cells were coincubated with Lobaplatin and multi-caspase inhibitor ZVAD-fmk, in order to check if cell death induced by Lobaplatin can be abrogated by inhibition of classical apoptosis. Cytotoxic effects were evaluated by crystal-violet assay. To investigate in which phase of the cell cycle cytotoxicity is most pronounced, cell cycle FACS analysis was performed after treatment with various concentrations of Lobaplatin.Results:Lobaplatin showed a somewhat better anti-tumor activity in both cell lines than Cisplatin. Lobaplatin Induced cleavage of PARP and procaspase 3 indicative for induction of classical apoptosis. However, cytotoxic effects of Lobaplatin were not decreased by multi-caspase inhibitor ZVAD-fmk. Cell-cycle FACS analysis showed, that sub-G0/1 fraction (indicactive for apoptotic/necrotic cells) was increased and G2 fraction was decreased dose-dependently by treatment with Lobaplatin.Conclusion:Lobaplatin showed a good anti-tumor activity in in vitro models of triple negative breast cancers which was at least equal to Cisplatin. Main mechanism of ytotoxicity was programmed cell death, which could not be abrogated by multi-caspase inhibition. Due to the good anti-tumor activity and the favorable toxicity profile, Lobaplatin should be considered for clinical studies in triple negative breast cancers.*Aeterna/Zentaris GmbH, Frankfurt/M

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6115.

Expression of LHRH receptors in prostate cancer cells prior to therapy, following castration, or following treatment with LHRH agonists

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Background: In the treatment of advanced prostate cancer, the effects of luteinizing hormone releasing hormone (LHRH) agonists are mediated through the down-regulation of pituitary LHRH receptors, inhibiting the pituitary-gonadal axis. Several groups have demonstrated LHRH receptor expression on prostate cancer cells. These tumoral receptors have been shown to mediate direct inhibitory effects in vitro. That expression of LHRH receptors persists in the castrate resistant state. To date, there is no information on LHRH receptor expression on the prostate after LHRH agonist therapy. This study investigates the expression of LHRH receptors following prolonged exposure to LHRH agonists. Methods: Expression of LHRH receptors was determined using immunohistochemistry and the intensity was graded on a scale from zero to 3. The expression was analyzed in three cohorts of patients: (1) 47 men with localized prostate cancer treated with radical prostatectomy with no hormone therapy, (2) 61 men with localized prostate cancer treated with neoadjuvant LHRH agonists for varying duration prior to prostatectomy, and (3) 22 men with metastatic prostate cancer who received a palliative transurethral resection of the prostate after clinical progression. In the final cohort, 15 men were treated with castration and 7 were treated with LHRH agonists. Results: 45 of 47 hormone naïve samples (95.7%) demonstrated LHRH receptor expression. Statistical analysis revealed a correlation between strong receptor expression and higher pathologic tumor stage as well as shorter overall survival. 60 of 61 samples treated with neoadjuvant LHRH agonist therapy (98.4%) demonstrated LHRH receptor expression. All 22 samples from patients with metastatic disease demonstrated LHRH receptor expression. The majority of these samples demonstrated moderate to strong intensity. Conclusions: LHRH receptors are expressed on prostate cancers cells of hormone naïve and castrated patients. The expression of these receptors appears to persist despite prolonged treatment with LHRH agonists. The continued expression of these receptors supports the concept of targeting prostatic LHRH receptors to deliver cytotoxic therapy based on LHRH analogs, such as AN-152.

[Table: see text]

The -174G>C IL-6 gene promoter polymorphism and diabetic microvascular complications

This study examined a possible association of the G>C polymorphism at nucleotide -174 in the promoter region of the interleukin-6 (IL-6) gene (rs1800795) with the prevalence of diabetic complications in 235 patients with type 1 and 498 patients with type 2 diabetes. Genotyping was performed using polymerase chain reaction (PCR) and subsequent cleavage by Nla III restriction endonuclease. Analyzing all diabetic patients together demonstrated that 301 patients (41.1%) carried the GG genotype, 114 (15.6%) the CC genotype, and 318 (43.3%) were heterozygous for the GC genotype. However, there was no correlation of any of the genotypes with the prevalence of diabetic nephropathy or diabetic neuropathy, but subjects with the CC genotype had a significantly higher prevalence of diabetic retinopathy compared to patients with the GC and GG genotype (p=0.016). This association was mainly lost when a logistic regression model was adjusted for diabetes duration (p=0.07). Consistently, a weak but not significant association of the polymorphism with diabetic retinopathy was observed when type 1 and type 2 diabetic patients were analyzed separately (patients with type 1 diabetes: p=0.12; patients with type 2 diabetes: p=0.09). Analogically, no association of the polymorphism was found for diabetic nephropathy or diabetic neuropathy in these groups. In conclusion these data suggest no major influence of the -174G>C variant in the promoter region of the IL-6 gene on the development of microvascular complications in patients with diabetes.

[Ten years of epidemiological cancer registration in Bavaria]

For a large territorial state like Bavaria only a decentralised cancer registration structure promises successful results: in the form of regional clinical cancer registries and--using the clinical registration as a base--one population-based registry. After ten years of epidemiological cancer registration in Bavaria it can now be shown that the chosen registration concept has proved itself. Currently the completeness of cancer notifications exceeded the international recommended threshold of 90%. A largely complete data stock is available for the years of diagnosis from 2004 to 2005. The task sharing between clinical and population-based cancer registries avoids double registration of data. Both types of registries are supporting physicians and hospitals with a wide palette of services. Together they enable transparency of cancer occurrence as well as transparency of health care for tumour patients.

FDG-PET/MRI coregistration improves detection of cortical dysplasia in patients with epilepsy

OBJECTIVE

Patients with cortical dysplasia (CD) are difficult to treat because the MRI abnormality may be undetectable. This study determined whether fluorodeoxyglucose (FDG)-PET/MRI coregistration enhanced the recognition of CD in epilepsy surgery patients.

METHODS

Patients from 2004-2007 in whom FDG-PET/MRI coregistration was a component of the presurgical evaluation were compared with patients from 2000-2003 without this technique. For the 2004-2007 cohort, neuroimaging and clinical variables were compared between patients with mild Palmini type I and severe Palmini type II CD.

RESULTS

Compared with the 2000-2003 cohort, from 2004-2007 more CD patients were detected, most had type I CD, and fewer cases required intracranial electrodes. From 2004-2007, 85% of type I CD cases had normal non-University of California, Los Angeles (UCLA) MRI scans. UCLA MRI identified CD in 78% of patients, and 37% of type I CD cases had normal UCLA scans. EEG and neuroimaging findings were concordant in 52% of type I CD patients, compared with 89% of type II CD patients. FDG-PET scans were positive in 71% of CD cases, and type I CD patients had less hypometabolism compared with type II CD patients. Postoperative seizure freedom occurred in 82% of patients, without differences between type I and type II CD cases.

CONCLUSIONS

Incorporating fluorodeoxyglucose-PET/MRI coregistration into the multimodality presurgical evaluation enhanced the noninvasive identification and successful surgical treatment of patients with cortical dysplasia (CD), especially for the 33% of patients with nonconcordant findings and those with normal MRI scans from mild type I CD.

[Elective lymph node dissections--still a standard in cancer surgery?]

PURPOSE

Since more than a century elective radical dissection of regional lymph nodes is a standard procedure in tumour surgery. We discuss whether or not this standard is still up to date.

METHODS

The discussion was based on evaluations from well known clinical trials and cohort studies as well as from the results of the Munich Cancer Registry (MCR).

RESULTS

Distant metastases develop extravasally from disseminated tumour cells that originate from the primary tumour. Therefore, three categories of metastases can be described: First, regional lymph node metastases treated by surgical and/or adjuvant therapy or by watchful waiting. Although the number of positive lymph nodes is one of the most important prognostic factor in all cancer sites, treatment of lymph nodes does not affect long-term survival. The number of positive lymph nodes is therefore simply a marker, but not a cause, of distant metastases. This seems to be generally valid. Also, the major part of local recurrences can be seen as "local metastases". The frequency of local relapse can be influenced by surgery, adjuvant treatment or radiotherapy only with a small impact on survival. Distant metastases normally determine the course of disease. Whether metastases can be a source of new clinically relevant metastases that influence the prognosis has to be questioned by the presented analyses of tumour growth times.

CONCLUSIONS

The gene-based control of metastases implies a principal process of metastatic spread for solid tumours. The hypothesis "metastases do not metastasise" has a high plausibility. Reduction of lymph node dissection and its performance only in those cases where it is necessary for treatment decisions seems to be (bio)-logically consequent.

Pressure-induced phase transition in PbSc0.5Ta0.5O3 as a model Pb-based perovksite-type relaxor ferroelectric

We report pressure-induced structural changes in PbSc(0.5)Ta(0.5)O3 studied by single-crystal x-ray diffraction and Raman scattering. The appearance of a soft mode, a change in the volume compressibility, broadening of the diffraction peaks, and suppression of the x-ray diffuse scattering show that a phase transition occurs near pc approximately 1.9 GPa. The critical pressure is associated with a decoupling of the displacements of the B site and Pb cations in the existing polar nanoregions, leading to the suppression of B-cation off-center shifts and enhancement of the ferroic distortion in the Pb-O system.

Laminin, proteoglycan, nidogen and collagen IV: structural models and molecular interactions

Major components of basement membranes, including collagen IV, laminin, heparan sulphate proteoglycan and nidogen, were isolated from the matrix of the EHS sarcoma. The purified components were analysed for their domain structure and for the participation of distinct domains in molecular interactions and cell binding. Collagen IV consists of four domains which have triple helical or non-collagenous structures. Self-assembly of the protein into a network-like organization occurs by specific interactions between N-terminal triple helical segments and between the C-terminal globules. Cell binding requires a central triple helical segment. Laminin has the shape of an asymmetrical cross; different globular domains within this structure mediate binding to proteoglycan and to cells. The proteoglycan consists of four heparan sulphate chains attached to a small protein core. These chains have the potential to bind laminin, fibronectin and collagen IV. Nidogen was isolated in several molecular forms which showed either self-aggregation or binding to laminin.