Martin Weiss

Cold Atmospheric Plasma Treatment Induces Anti-Proliferative Effects in Prostate Cancer Cells by Redox and Apoptotic Signaling Pathways

One of the promising possibilities of the clinical application of cold plasma, so-called cold atmospheric plasma (CAP), is its application on malignant cells and cancer tissue using its anti-neoplastic effects, primarily through the delivery of reactive oxygen and nitrogen species (ROS, RNS). In this study, we investigated the impact of CAP on cellular proliferation and consecutive molecular response mechanisms in established prostate cancer (PC) cell lines. PC cells showed a significantly reduced cell growth following CAP treatment as a result of both an immediate increase of intracellular peroxide levels and through the induction of apoptosis indicated by annexin V assay, TUNEL assay, and the evaluation of changes in nuclear morphology. Notably, co-administration of N-acetylcysteine (NAC) completely neutralized CAP effects by NAC uptake and rapid conversion to glutathione (GSH). Vitamin C could not counteract the CAP induced effects on cell growth. In summary, relatively short treatments with CAP of 10 seconds were sufficient to induce a significant inhibition of cancer proliferation, as observed for the first time in urogenital cancer. Therefore, it is important to understand the mode of CAP related cell death and clarify and optimize CAP as cancer therapy. Increased levels of peroxides can alter redox-regulated signaling pathways and can lead to growth arrest and apoptosis. We assume that the general intracellular redox homeostasis, especially the levels of cellular GSH and peroxidases such as peroxiredoxins affect the outcome of the CAP treatment.

Immediate and transient phosphorylation of the heat shock protein 27 initiates chemoresistance in prostate cancer cells

Drug resistance minimizes the effects of prostate cancer (PC) chemotherapy with docetaxel and is generally considered to be associated with the expression of heat shock protein (HSP) 27 including various cytoprotective pathways. In the present study, we investigated the effects of HSP27 phosphorylation on PC cell growth underlying docetaxel treatment. Cell counting revealed significantly reduced cell growth during docetaxel treatment as a result of both activation of mitogen-activated protein kinase p38 (MAPK p38) and protein kinase D1 (PKD1), and, most importantly, the overexpression of the phosphorylation-mimicking mutant HSP27-3D. Further analysis revealed a docetaxel-dependent induction of HSP27 accompanied by an initial phosphorylation and rapid dephosphorylation of the protein. Based on the data, we can conclude that phosphorylation of HSP27 protein is a crucial mechanism in the initiation of chemoresistance in PC. Moreover, the results indicate a key impact of HSP27 on viability and proliferation of PC cells underlying anticancer therapy. The protective function depends on the initial phosphorylation status of HSP27 and represents a putative co-therapeutic target to prevent chemoresistance during docetaxel therapy.

Cytochrome P450 17A1 inhibitor abiraterone attenuates cellular growth of prostate cancer cells independently from androgen receptor signaling by modulation of oncogenic and apoptotic pathways

Abiraterone provides significant survival advantages in prostate cancer (PC), however, the current understanding of the molecular mechanisms of abiraterone is still limited. Therefore, the abiraterone impact on androgen receptor (AR)-positive LNCaP and AR-negative PC-3 cells was assessed by cellular and molecular analyses. The present study demonstrated, that abiraterone treatment significantly decreased cell growth, AR expression, and AR activity of AR-positive LNCaP cells. Notably, AR-negative PC-3 cells exhibited comparable reductions in cellular proliferation, associated with DNA fragmentation and pro-apoptotic modulation of p21, caspase-3, survivin, and transforming growth factor β (TGFβ). Our observations suggest that the attenuation of AR signaling is not the only rationale to explain the abiraterone anticancer activity. Abiraterone efficacy may play a more global role in PC progression control than originally hypothesized. In this regard, abiraterone is not only a promising drug for treatment of AR-negative PC stages, even more, abiraterone may represent an alternative for treatment of other malignancies besides prostate cancer.

MicroRNA-1 properties in cancer regulatory networks and tumor biology

Short non-coding microRNAs have been identified to orchestrate crucial mechanisms in cancer progression and treatment resistance. MicroRNAs are involved in posttranscriptional modulation of gene expression and therefore represent promising targets for anticancer therapy. As mircoRNA-1 (miR-1) exerted to be predominantly downregulated in the majority of examined tumors, miR-1 is classified to be a tumor suppressor with high potential to diminish tumor development and therapy resistance. Here we review the complex functionality of miR-1 in tumor biology.

Clinical Outcome of Neoadjuvant Radiochemotherapy in Locally Advanced Cervical Cancer: Results of an Open Prospective, Multicenter Phase 2 Study of the North-eastern German Society of Gynecological Oncology

Objective The aim of this study was to determine the response rate, toxicity, operability, and surgical complication rate of neoadjuvant concomitant radiochemotherapy (cRCH) (ifosfamide + carboplatin) followed by radical hysterectomy plus external-beam radiotherapy with curative intention in locally advanced primary inoperable stages IIB and IIIB squamous cell cervical cancer. Methods Patients with cervical cancer from 8 departments were enrolled. Patients received 3 cycles of ifosfamide 1.2 mg/m2 (+mesna 20%) plus carboplatin (area under the curve = 4), every 21 days, and concomitant external-beam radiotherapy (50.4 Gy [1.8 Gy/d]). Operability and remission were evaluated by clinical gynecological examination in general anesthesia (magnetic resonance imaging was optional), 4 weeks after the third cycle of cRCH. In case of achieved operability, a radical hysterectomy with pelvic lymphadenectomy was performed within 6 weeks after cRCH. If surgery was not performed because of incomplete remission or patient preferences, vaginal brachytherapy (15 Gy [5 Gy/d]) was given additionally. Results Forty-four patients were enrolled. Distribution of FIGO (International Federation of Gynecology and Obstetrics) tumor stage was as follows: IIB (19 patients) and IIIB (25 patients). All patients completed cRCH. Grade 3/4 hematologic toxicities (% of all cycles) were moderate: leukopenia, 7.3; thrombocytopenia, 2.4; and anemia, 3.2. In 13.8%, treatment cycles were delayed because of hematologic toxicity. Blood transfusions were given in 17.7% and granulocyte colony-stimulating factor in 39.5%. Overall, grade 3/4 nonhematologic toxicities were seldom (6.5%). Clinical overall response rate was 95.2%. Operability was achieved in 85.7%. Surgery was performed in 83.3%. Pathological response rates were as follows: pathological complete remission, 33.3%; partial remission, 63.3%; stable disease, 3.3%. Conclusions Our study demonstrates that cRCH is an effective and tolerable regimen in locally advanced cervical cancer treatment.

Cytochrome P450 17A1 Inhibitor Abiraterone Acetate Counteracts the Heat Shock Protein 27's Cell Survival Properties in Prostate Cancer Cells

Introduction: Inhibition of androgen synthesis by abiraterone acetate (AA) entails enhanced overall survival rates and clinical benefit for patients with locally advanced and metastasized prostate cancer (PC). The expression of heat shock protein 27 (HSP27) is generally associated with cytoprotection and was demonstrated to mediate chemoresistance under cytostatic therapy, for instance, docetaxel treatment. In this study, we investigated the impact of AA treatment on HSP27 expression and PC cell growth. Materials and Methods: HSP27 expression levels in docetaxel and AA-treated PC cell lines LNCaP and PC-3 were determined by SDS PAGE and Western blot analysis. Proliferation assays were performed using a CASY Cell Counter and Analyzer Model TT (Roche Applied Science). Results: Despite significantly increased HSP27 expression in PC cells incubated with docetaxel, Western blot analysis implicated a significant reduction of the cytoprotective HSP27 in AA-treated PC cells. Notably, HSP27 stably overexpressed in PC-3-HSP27 cells did not appear as an HSP27-mediated proliferation benefit in the presence of AA as shown in docetaxel incubation studies. Conclusion: In contrast to repeatedly demonstrated HSP27-driven chemoresistance related to chemotherapeutics, our results may constitute a broader molecular mode of action of AA chemotherapy. AA efficacy may exert an HSP27 suppressive role that goes beyond the primarily assumed inhibition of androgen biosynthesis.

Physical plasma: a new treatment option in gynecological oncology

Non-thermal application of physical plasma is rapidly gaining importance for the future therapy and prevention of chronic inflammatory diseases and tumors. Here, we outline the importance of this innovative and less invasive therapy option, particulary for the treatment and prevention of gynecological cancers.