Effects of an Antagonistic Analog of Growth Hormone-Releasing Hormone on Endometriosis in a Mouse Model and In Vitro.

Endometriosis is a benign gynecologic disorder causing dysmenorrhea, pelvic pain, and subfertility. Receptors for the growth hormone-releasing hormone (GHRH) were found in endometriotic tissues. Antagonists of GHRH have been used to inhibit the growth of endometriotic endometrial stromal cells. In this study, the GHRH receptor splice variant (SV) 1 was detected in human endometrial tissue samples by Western blots and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The highest messenger RNA (mRNA) and protein levels of SV1 were found in eutopic endometrium from patients with endometriosis compared to ectopic endometriotic tissues and endometrium from normal patients. The highest expression for GHRH mRNA was found by qRT-PCR in ectopic endometriosis lesions. In an in vivo mouse model with human endometrial explants from patients with endometriosis, 10 µg MIA-602 per day resulted in significantly smaller human endometrial xenotransplants after 4 weeks compared to mice treated with vehicle. The endometrial tissues expressed SV1 before and after xenotransplantation. The proliferation of endometrial stromal cells as well as the endometriosis cell lines 12-Z and 49-Z was decreased by exposure to 1 µM MIA-602 after 72 hours. The protein levels of epithelial growth factor receptors in 12-Z and 49-Z cell lines were reduced 48 and 72 hours after the administration of 1 µM MIA-602. MIA-602 decreased the activation of the MAP-kinases ERK-1/2. Our study demonstrates the presence of SV1 receptor as a target for treatment with GHRH antagonist in endometriosis. Endometrial tissues respond to MIA-602 with inhibition of proliferation in vitro and in vivo. The use of MIA-602 could be an effective supplement to the treatment strategies in endometriosis.

Targeting of Peptide Cytotoxins to LHRH Receptors For Treatment of Cancer.

Receptors for LHRH (luteinizing hormone-releasing hormone) are expressed in about 80% of human endometrial, ovarian and prostate cancers and are also found in more than 50% of breast cancers including triple negative breast cancers. In the human body, LHRH receptors are found at significant levels in the pituitary and reproductive organs. Other benign tissues or hematopoietic stem cells express only low levels of receptors for LHRH or no receptors. Thus LHRH receptors are promising targets for a receptor- mediated chemotherapy with cytotoxic hybrid molecules. Cytotoxic analogs of LHRH consist of a LHRH agonist, which is used as a carrier peptide and DOX or its derivatives. Cytotoxic analogs of LHRH, AEZS-108 (formerly known as AN-152) and AN-207, exhibit anti-cancer activity in various in vitro and in vivo models of LHRH-receptor positive cancers. In AEZS-108 (zoptarelin DOX) DOX is covalently linked to the LHRH agonist [D-Lys(6)]LHRH. Results of phase I and II clinical studies in patients with breast, endometrial and ovarian cancers demonstrated good anticancer activity with moderate toxic side effects and without any sign of cardiotoxicity so far. AEZS-108 is also being evaluated in phase I/II studies in castration resistant prostate cancer and metastatic bladder cancer. Because of the very promising phase II results in endometrial cancer, a multinational, multicenter phase III study of this malignancy has been initiated and is currently recruiting patients.

Anti-tumour activity of phosphoinositide-3-kinase antagonist AEZS-126 in models of ovarian cancer.

PURPOSE: Platinum resistance is the most crucial problem for treatment of ovarian cancer. There is a clinical need for new treatment strategies which overcome platinum resistance. Recently high level of AKT was shown to be involved in platinum resistance and furthermore in resistance against Natural-killer (NK)-cell mediated killing in ovarian cancer. METHODS: Here, we investigate the ability of the PI3K/AKT inhibitor AEZS-126 alone and in combination with rapamycin to selectively target ovarian cancer cell proliferation and survival in vitro by MTT-assays and FACS based analysis. Furthermore the mechanism of cytotoxicity is analysed by FACS based assays. The NK-killing efficiency of ovarian cancer cells with and without pre-treatment with AEZS-126 was analysed. RESULTS: AEZS-126 showed good anti-tumour activity in in vitro models of ovarian cancer. Main mechanism of cytotoxicity seems to be necroptosis which could be abrogated by co-incubation with necrostatin-1. Furthermore pre-treatment of platinum resistant cells with AEZS-126 resulted in an increased accessibility of these tumour cells for killing by NK-cells. CONCLUSION: We demonstrated the highly efficient anti-tumour activity of AEZS-126 in in vitro models of ovarian cancer. Due to the good anti-tumour activity and the expected increase in NK-cell mediated killing even of platinum resistant tumour cells, AEZS-126 seems to be a promising candidate for clinical testing in ovarian cancer.

Prognostic impact of infiltration of the vagina and/or uterus in women undergoing anterior pelvic exenteration for urothelial carcinoma of the bladder: results of a contemporary multicentre series.

PURPOSE: To evaluate for the first time the prognostic significance of female invasive patterns in stage pT4a urothelial carcinoma of the bladder in a large series of women undergoing anterior pelvic exenteration. PATIENTS AND METHODS: Our series comprised of 92 female patients in total of whom 87 with known invasion patterns were eligible for final analysis. Median follow-up for evaluation of cancer-specific mortality (CSM) was 38 months (interquartile ranges, 21-82 months). The impact on CSM was evaluated using multivariable Cox proportional-hazards regression analysis; predictive accuracy (PA) was assessed by receiver operating characteristic analysis. RESULTS: Vaginal invasion was noted in 33 patients (37.9 %; group VAG), uterine invasion in 20 patients (23 %; group UT), and infiltration of both vagina and uterus in 34 patients (39.1 %; group VAG + UT). Groups VAG and UT significantly differed from group VAG + UT with regard to the presence of positive soft tissue margins (STM) only. Five-year-cancer-specific survival probabilities in the groups VAG, UT, and VAG + UT were 21, 20, and 21 %, respectively (p = 0.955). On multivariable analysis, only STM status (HR = 2.02, p = 0.023) independently influenced CSM. C-indices of multivariable models for CSM with and without integration of invasive patterns were 0.570 and 0.567, respectively (PA gain 0.3 %, p = 0.526). CONCLUSIONS: Infiltration of the vagina, the uterus or both is associated with poor 5-year survival rates. With regard to CSM, no difference was detectable between patients with different invasion patterns, thus justifying further collectively including these invasive patterns as stage pT4a.

Mechanisms of tumor immune escape in triple-negative breast cancers (TNBC) with and without mutated BRCA 1.

PURPOSE: Triple negative breast cancers (TNBC) are associated with an adverse outcome, although these tumors are sensitive to chemotherapy. In part, this phenomenon could be caused by tumor immune escape. The current study investigates immunogenicity of TNBC cells in vitro and the presence of immunosuppressive factors in the tumor microenvironment (pAKT and B7H1 expression, infiltration with regulatory T cells, [Tregs]). METHODS: Natural killer (NK)-cell induced lysis was evaluated in estrogen receptor (ER) positive MCF 7 breast cancers, in MDA-MB231 and MDA-MB468 and in HCC-1937 (BRCA 1 mutated) and HCC-1806 TNBC cells. Expression of pAKT, B7H1 and infiltration with Tregs were determined by immunohistochemistry in human specimens of benign and malignant breast disease. RESULTS: NK-cell induced lysis was significantly increased (p < 0.05) in four TNBC cell lines compared to ER + MCF 7 cells. Fibroadenomas and mastectomy samples were not infiltrated with Tregs. Infiltration with Tregs was 0.92 ± 0.21 in ER/PR + breast cancers and significantly higher in TNBC without (2.30 ± 0.34) and also significantly higher with mutation of BRCA 1 (2.10 ± 0.34). Expression of pAKT was absent in benign controls and 1.23 ± 0.36 in ER/PR + breast cancers, 1.78 ± 0.40 in TNBC without and 2.40 ± 0.30 with mutated BRCA 1. No significant differences of B7H1 expression occurred among the breast cancer subgroups. CONCLUSION: TNBC cell stimulate the NK-cell immune response significantly stronger than ER positive breast cancer cells. This could explain why infiltration with immunosuppressive Tregs is increased in human specimens of TNBC with and without mutated BRCA 1. Accordingly, immunomodulatory treatment strategies should be further explored in TNBC.

Immune escape of AKT overexpressing ovarian cancer cells.

Platinum-resistance is the most crucial problem for treatment of ovarian cancer. There is a clinical need for new treatment strategies which overcome platinum resistance. As survival is strongly influenced by immunological parameters, immunotherapeutic strategies appear promising. Therefore a better understanding of the interaction between ovarian tumour cells and cells of the immune system is a necessary prerequisite. In the present study we aimed to enlighten the interactions between platinum resistant and platinum sensitive ovarian cancer cells and natural-killer (NK)-cells. Modified FATAL assay was used for determining the killing efficiency of NK-cells for the parental A2780 cells and the cis-platinum resistant A2780cis human ovarian cancer cells. Expression of pro- and anti-apoptotic genes as well as ligands involved in NK-cell receptor recognition were analysed by RT-PCR and flow cytometric analysis. The efficiency of NK mediated cell lysis differs between A2780 cells and the cis-platinum-resistant A2780cis cells. A2780cis cells are less accessible for NK-cell mediated killing. Based on this observation we characterized the molecular basis for resistance mechanisms. Besides an increase in anti-apoptotic genes (especially CIAP-1 and -2) that probably render A2780cis cells more resistant against apoptosis an increased amount of soluble MICA/B seems to be responsible for the lower killing rate of platinum-resistant A2780cis cells compared to their parental A2780 cells.

Anti-tumour activity of phosphoinositide-3-kinase antagonist AEZS 126 in models of triple-negative breast cancer.

PURPOSE: Of more than one million global cases of breast cancer diagnosed each year, a high percentage are characterized as triple-negative, lacking the oestrogen, progesterone and Her2/neu receptors. The incidence exceeds the incidence of malignancies like CML by far. Lack of effective therapies, younger age at onset and early metastatic spread have contributed to the poor prognosis and outcomes associated with these malignancies. METHODS: Here, we investigate the ability of the PI3K/AKT inhibitor AEZS 126 to selectively target the triple-negative breast cancer (TNBC) cell proliferation and survival in vitro by MTT-assays and FACS-based analysis. Furthermore, the mechanism of cytotoxicity is analysed by FACS-based assays and Western blots. RESULTS: AEZS 126 showed good anti-tumour activity in in vitro models of TNBC as well as in MCF-7 cells. Main mechanism of cytotoxicity seems to be programmed cell death after an incubation time of 72 h, which could be abrogated by co-incubation with z-VAD-fmk in MCF-7 and MDA-MB468 cells. In HCC1806 cells, addition of necrostatin-1 has only slightly protective effects, but in HCC1937 cells, the addition of necrostatin-1 has the same protective effect as co-incubation with z-VAD-fmk, and this observation argues for cell death caused by apoptosis and necroptosis in this cell line. CONCLUSION: We demonstrated the highly efficient anti-tumour activity of AEZS 126 in in vitro models of TNBC. Due to the good anti-tumour activity and the expected favourable toxicity profile, AEZS 126 in combination with chemotherapy seems to be a promising candidate for clinical testing in TNBC especially in the basal-like subgroup of TNBC.

Effects of lobaplatin as a single agent and in combination with TRAIL on the growth of triple-negative p53-mutated breast cancers in vitro.

Lobaplatin as a single agent and in combination with tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is investigated in in-vitro models of p53-negative triple-negative breast cancers (TNBCs) and compared with a model of oestrogen receptor-positive p53-positive breast cancer. In addition, the induction of programmed cell death by lobaplatin is further explored. By using cell viability assays and western blotting, the cytotoxic effects of lobaplatin alone and in combination with TRAIL are compared with cisplatin in HCC 1806, HCC 1937, and MCF 7 cells. The multicaspase inhibitor z-VAD-fmk and necrostatin, an inhibitor of necroptosis, are used to demonstrate the mechanism of cell death caused by lobaplatin. Lobaplatin displayed antitumour activity in all three cell lines, which increased time dependently. Cotreatment of lobaplatin and TRAIL induced an increase in cytotoxicity by 30-50% in the different cell lines. The pan-caspase inhibitor z-VAD-fmk as well as necrostatin could weaken but not abolish the cytotoxic effect of lobaplatin and cisplatin. Lobaplatin showed substantial cytotoxic effects in two in-vitro models of p53-mutated TNBC. Cotreatment with TRAIL and platinum agents resulted in increased antitumour activity in the TNBC cell lines investigated. Cell death subsequent to treatment with cisplatin and lobaplatin occurred because of apoptosis. However, caspase-independent mechanisms of programmed cell death were also involved. It was also demonstrated that platinum compounds could induce necroptosis, although to a minor extent.

Search for novel therapies for triple negative breast cancers (TNBC): analogs of luteinizing hormone-releasing hormone (LHRH) and growth hormone-releasing hormone (GHRH).

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that is clinically negative for the expression of estrogen and progesterone receptors (ER/PR) and human epidermal growth factor receptor-2 (HER2). Patients with TNBC have a worse clinical outcome, as measured by time to metastasis and median overall survival. Chemotherapy has been the mainstay of treatment of TNBC but responses are disappointing. A substantial proportion of TNBC expresses luteinizing hormone-releasing hormone (LHRH), receptors for LHRH, in addition to receptors for growth hormone-releasing hormone (GHRH). These receptors represent potential therapeutic targets. Potent antagonists of GHRH and LHRH receptors have been developed in recent years and these antagonists inhibit the growth, tumorigenicity and metastatic potential of various human experimental malignancies. These antagonists could be utilized for the treatment of TNBC. The targeted cytotoxic analog of LHRH, AN-152 (AEZS-108) containing doxorubicin, must also be strongly considered for therapy of TNBC. Experimental studies suggest the merit of clinical trials with LHRH antagonists and AEZS-108 in TNBC patients.

Papillary squamotransitional cell carcinoma of the vagina.

A case of a papillary squamotransitional cell carcinoma (PSTCC) of the vagina with a follow-up of 3 years is presented here. The characteristics of this case support a squamous rather than urothelial origin of this rare entity. Unlike its counterparts in the cervix uteri, the clinical behavior of vaginal PSTCC is more favorable than squamous cell carcinoma. Histological and clinical features are compared to those of previously described cases of vaginal and cervical PSTCC.

Ectonucleotidases CD39 and CD73 on OvCA cells are potent adenosine-generating enzymes responsible for adenosine receptor 2A-dependent suppression of T cell function and NK cell cytotoxicity.

The ectonucleotidases CD39 and CD73 degrade immune stimulatory ATP to adenosine that inhibits T and NK cell responses via the A(2A) adenosine receptor (ADORA2A). This mechanism is used by regulatory T cells (T(reg)) that are associated with increased mortality in OvCA. Immunohistochemical staining of human OvCA tissue specimens revealed further aberrant expression of CD39 in 29/36 OvCA samples, whereas only 1/9 benign ovaries showed weak stromal CD39 expression. CD73 could be detected on 31/34 OvCA samples. While 8/9 benign ovaries also showed CD73 immunoreactivity, expression levels were lower than in tumour specimens. Infiltration by CD4(+) and CD8(+) T cells was enhanced in tumour specimens and significantly correlated with CD39 and CD73 levels on stromal, but not on tumour cells. In vitro, human OvCA cell lines SK-OV-3 and OaW42 as well as 11/15 ascites-derived primary OvCA cell cultures expressed both functional CD39 and CD73 leading to more efficient depletion of extracellular ATP and enhanced generation of adenosine as compared to activated T(reg). Functional assays using siRNAs against CD39 and CD73 or pharmacological inhibitors of CD39, CD73 and ADORA2A revealed that tumour-derived adenosine inhibits the proliferation of allogeneic human CD4(+) T cells in co-culture with OvCA cells as well as cytotoxic T cell priming and NK cell cytotoxicity against SK-OV3 or OAW42 cells. Thus, both the ectonucleotidases CD39 and CD73 and ADORA2A appear as possible targets for novel treatments in OvCA, which may not only affect the function of T(reg) but also relieve intrinsic immunosuppressive properties of tumour and stromal cells.

Induction of programmed cell death by inhibition of AKT with the alkylphosphocholine perifosine in in vitro models of platinum sensitive and resistant ovarian cancers.

PURPOSE: We analyzed the anti-tumor effect and the mechanism of action of perifosine, an orally active alkylphospholipid AKT inhibitor using in vitro models of human ovarian cancer. METHODS: Ovarian cancer cells OAW42, PA-1, SKOV3, and A2780 as well as platinum resistant A2780cis cells were incubated with increasing concentrations of perifosine, with and without multi-caspase inhibitor zVAD-FMK. The effect of a combined treatment with cisplatin and perifosine was investigated in OAW42, SKOV3, A2780 and A2780cis cells. Cytotoxic effects of perifosine were analyzed using crystal violet staining, FACS analysis of DNA content as well as Annexin V/propidium iodide-double staining. The effect of perifosine on AKT phosphorylation was determined by Western blotting. RESULTS: Perifosine displayed anti-tumor activity in all five cell lines, which increased time-dependently. While IC(50) values at 24 h were >40 µM, IC(50) values after 72 h decreased to 10 µM in OAW42 and 25 µM in PA-1 and 30 µm in SKOV3 cells. In platinum resistant A2780cis cells perifosine showed good antiproliferative activity (IC(50) = 3 µm). At adequate doses, perifosine increased cytotoxic effects of cisplatin in OAW42, A2780 and A2780cis cell. Anti-tumor activity of perifosine was not confined to a specific phase of the cell cycle and could not be decreased by the pan-caspase inhibitor zVAD-FMK. AnnexinV/propidium iodide-double staining after treatment with perifosine was not indicative of classical apoptosis. AKT phosphorylation was dose-dependently inhibited by perifosine. CONCLUSIONS: Perifosine showed substantial cytotoxic effects in various in vitro models of ovarian cancer. Since anti-tumor effects were not confined to platinum-sensitive cells perifosine seems to be a good candidate for clinical studies in patients especially with platinum resistant ovarian cancer.

Use of analogs of peptide hormones conjugated to cytotoxic radicals for chemotherapy targeted to receptors on tumors.

Specific receptors for luteinizing hormone-releasing hormone (LH-RH), somatostatin, bombesin, and other peptides are found on various cancers. We review the development of cytotoxic analogs of LH-RH, somatostatin, and bombesin/gastrin releasing peptide (GRP) designed for targeting chemotherapy to peptide receptors on various cancers. Cytotoxic analogs of LH-RH, AN-152 and AN-207, containing doxorubicin (DOX) or 2-pyrrolino-DOX (AN-201), respectively, target LH-RH receptors and may be used for the treatment of prostatic and urinary bladder (urothelial), breast, ovarian and endometrial cancers, non-Hodgkin's lymphomas, melanomas, and renal cell carcinomas. DOX and AN-201 have also been incorporated into the cytotoxic analogs of somatostatin, AN-162 and AN-238, respectively, which are targeted to receptors for somatostatin in prostatic, mammary, ovarian, gastric, renal, colorectal and pancreatic cancers, non-Hodgkin's lymphomas, as well as glioblastomas and lung cancers. They are found to suppress the growth of these tumors and their metastases. A cytotoxic analog of bombesin/GRP, AN-215, containing 2-pyrrolino-Dox, has also been synthesized and shown to inhibit growth of various human cancer lines expressing receptors for bombesin/GRP. The toxicity, pharmacokinetics and maximum tolerated doses of AN-152 were assessed in a phase I clinical trial in women with ovarian or endometrial cancer. Disease stabilization and objective responses were found. Analog AN-152 is now in phase II clinical trials. Phase I/II studies with AN-152 in men with hormone-independent relapsed prostate cancer and patients with pancreatic and bladder cancers are pending. Targeted cytotoxic peptide analogs could provide a more efficacious and less toxic therapy for various cancers.

Cervical endometriosis associated with malignant pleural mesothelioma mimicking cervical cancer--Occam's razor or the "third man".

OBJECTIVE: To illustrate pitfalls in the diagnosis of endometriosis and cervical cancer. DESIGN: Case report. SETTING: University hospital, department of obstetrics and gynecology. PATIENT(S): A 45-year-old woman with menorrhagia, pelvic mass, right-sided hydronephrosis, and unexplained weight loss. INTERVENTION(S): Cervical biopsies were suggestive of cervical endometriosis. Laparoscopy confirmed endometriosis. Associated pleural effusion, without cytologic signs of malignancy, was interpreted as caused by thoracic endometriosis. The patient had a transabdominal hysterectomy and unilateral salpingo-oophorectomy. Histopathologic examination confirmed endometriosis and revealed a residual tubo-ovarian abscess. After surgery, the patient developed spontaneous seropneumothorax. Pleural biopsies revealed a well-differentiated epithelial malignant pleural mesothelioma. The patient underwent hypofractionated radiation of drain sites. She is now observed in our outpatient clinic. MAIN OUTCOME MEASURE(S): Steps to the correct diagnosis. RESULT(S): The patient had an association of cervical and pelvic endometriosis, residual tubo-ovarian abscess, and malignant pleural mesothelioma. CONCLUSION(S): Usually, the simplest diagnosis explaining a complex of symptoms and clinical and diagnostic findings is the one most likely to be correct. This is an application of Occam's razor to medicine. Our case illustrates that occasionally the simplest and therefore most probable diagnosis can be wrong, and on these occasions one should consider a "third man."

Macrophage migration inhibitory factor expression in cervical cancer.

PURPOSE: The glycoprotein macrophage migration inhibitory factor (MIF) is a cytokine that has been shown to promote tumor progression and tumor immune escape in ovarian cancer. The present study investigates MIF in uterine cervical cancer. METHODS: Eighty surgical biopsies (32 cervical dysplasias, 23 in situ carcinomas and 25 invasive carcinomas) of uterine cervical tissue were evaluated immunohistochemically for MIF expression. In uterine cervical cancer cell lines SiHa and CaSki and their respective supernatants, MIF protein expression was analyzed by Western blotting, enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Immunohistochemical analysis shows that MIF is clearly overexpressed on the protein level in invasive cervical cancer compared to cervical dysplasias. MIF overexpression was confirmed by RT-PCR in surgical biopsies of invasive cervical cancer. Western blotting reveals that the MIF protein is overexpressed in SiHA und CaSki cervical cancer cell lines, whereas the ELISA reveals that cervical cancer cells secrete MIF. CONCLUSIONS: MIF has been shown to promote tumor immune escape mechanisms in other cancer entities, which makes it an interesting target for cancer therapy, given the known significance of immune mechanisms for uterine cervical cancer. The overexpression of MIF on the protein and mRNA level, as well as its secretion by cervical cancer cells points to a critical role of the protein for the pathogenesis of uterine cervical cancer.

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.

Tubulin inhibitor AEZS 112 inhibits the growth of experimental human ovarian and endometrial cancers irrespective of caspase inhibition.

AEZS 112 is an orally active small molecule anticancer drug which inhibits the polymerization of tubulin at low micromolar concentrations. The current study investigates the anti-tumor effect and the mechanism of action of AEZS 112 in in vitro models of human ovarian and endometrial cancers. Four human ovarian and 2 endometrial cancer cell lines were incubated with increasing concentrations of AEZS 112 with and without multi-caspase inhibitor zVAD-FMK for 72 hours. Cytotoxic effects of AEZS 112 were analyzed using crystal violet staining, FACS analysis of DNA content as well as Annexin V/propidium iodide-double staining. AEZS 112 displayed anti-tumor activity in all six cell lines. The EC50 determined after 72-h incubation for Ishikawa and HEC 1A was 0.0312 and 0.125 microm, respectively. The EC50 was 5 microm for SKOV 3 cells, 1 microm for 0.5 microm for OAW 42 cells, 0.125 microm for OvW 1 cells and 0.0312 microm for PA 1 cells. Cytotoxic effects of AEZS 112 could not be abrogated by caspase inhibition with pan-caspase inhibitor zVAD-fmk. Annexin V/propidium iodide-double staining after treatment with AEZS 112 was indicative of necrosis-like cell death. AEZS 112 dose-dependently increased non-vital hypodiploid cells and the cytotoxic effect was least pronounced in G2 phase of the cell cycle, indicating cell death during mitosis, as determined by FACS analysis. The orally active small molecule tubulin inhibitor AEZS 112 showed anti-tumor activity in human ovarian and endometrial cancer cell lines at low micromolar concentrations, which could not be abrogated by caspase inhibition and is therefore a good candidate for in vivo studies in these tumors.

Triple-negative breast cancers express receptors for growth hormone-releasing hormone (GHRH) and respond to GHRH antagonists with growth inhibition.

Triple-negative breast cancers do not express receptors for estrogen or progesterone and do not overexpress HER2. These tumors have an unfavorable prognosis and at present chemotherapy is the only treatment option. Because the antagonists of growth hormone-releasing hormone (GHRH) have been shown to inhibit growth of a variety of cancers by endocrine and paracrine/autocrine mechanisms, we evaluated the expression of GHRH receptors in human specimens of triple-negative breast cancers and the response to GHRH by in vitro models. In samples of triple-negative breast cancers we found mRNA expression for the GHRH receptor and its functional splice variant SV1 in 25 and 70% of the cases, respectively and for GHRH in 80% of the samples. Immunoreaction of SV1 was detected in the human triple-negative breast cancer cell line HCC1806 while HCC1937 was negative. The growth of HCC1806 was stimulated by GHRH(1-44)NH(2) and inhibited by GHRH antagonist MZ-J-7-118. In addition, in HCC1806 MAP-kinases ERK-1/2 were activated by GHRH. Our findings suggest the existence of an autocrine loop consisting of GHRH and GHRH receptors in triple-negative breast cancers. Our in vitro studies demonstrate that targeting the GHRH receptor may be a therapeutic option which should be evaluated in studies in vivo.

Perifosine inhibits growth of human experimental endometrial cancers by blockade of AKT phosphorylation.

OBJECTIVE: Perifosine is an orally active alkylphospholipid analog, which has shown anti-tumor activity in a variety of cancers by inhibition of AKT phosphorylation. The objective of the current study was to evaluate its efficacy in in vitro models of human endometrial cancer. STUDY DESIGN: The effect of 10microM and 40microM perifosine on AKT phophorylation in human endometrial cancer cell lines Ishikawa and HEC 1A was determined by Western blotting. To screen for a putative anti-tumor effect, HEC 1A and Ishikawa cells were incubated with increasing concentrations of perifosine for 24h, 48h and 72h and the number of viable cells was determined by crystal violet staining. Also the effect of a combined treatment with cisplatin and perifosine was investigated in Ishikawa cells. Flow cytometric analysis of DNA content was used to determine the effect of perifosine on the cell cycle distribution of HEC 1A and Ishikawa cells and to assess potential toxic side effects of perifosine on peripheral blood lymphocytes (PBL). RESULTS: AKT phosphorylation was dose-dependently inhibited by perifosine. Concomitantly, perifosine displayed anti-tumor activity in both cell lines at concentrations that showed no effect on peripheral blood lymphocytes. Growth inhibitory effects became more pronounced with increasing treatment time. While IC 50 values at 24h were >40microM, IC 50 values after 48h were approximately 7microM in Ishikawa and 25microM in HEC 1A cells. After 72h, the IC 50 was below 1.25microM for Ishikawa and about 6microM for HEC 1A cells. Perifosine cotreatment substantially increased cytotoxic effects of cisplatin in human Ishikawa endometrial cancer cells. Of note, the anti-tumor activity of perifosine was not confined to a specific phase of the cell cycle. CONCLUSIONS: The small molecule AKT inhibitor perifosine showed substantial anti-tumor activity in human endometrial cancer cell lines. Since these effects were increased with cisplatin, perifosine seems to be a good candidate for treatment combinations with classical cytostatic compounds. Thus, perifosine should be further evaluated in clinical studies in endometrial cancer.