Identification of 14-3-3β gene as a novel miR-152 target using a proteome-based approach

Recent studies demonstrated that miR-152 overexpression down-regulates the nonclassical human leukocyte antigen (HLA) class I molecule HLA-G in human tumors thereby contributing to their immune surveillance. Using two-dimensional gel electrophoresis followed by MALDI-TOF mass spectrometry, the protein expression profile of HLA-G(+), miR-152(low) cells, and their miR-152-overexpressing (miR(high)) counterparts was compared leading to the identification of 24 differentially expressed proteins. These were categorized according to their function and localization demonstrating for most of them an important role in the initiation and progression of tumors. The novel miR-152 target 14-3-3 protein β/α/YWHAB (14-3-3β) is down-regulated upon miR-152 overexpression, although its overexpression was often found in tumors of distinct origin. The miR-152-mediated reduction of the 14-3-3β expression was accompanied by an up-regulation of BAX protein expression resulting in a pro-apoptotic phenotype. In contrast, the reconstitution of 14-3-3β expression in miR-152(high) cells increased the expression of the anti-apoptotic BCL2 gene, enhances the proliferative activity in the presence of the cytostatic drug paclitaxel, and causes resistance to apoptosis induced by this drug. By correlating clinical microarray data with the patients' outcome, a link between 14-3-3β and HLA-G expression was found, which could be associated with poor prognosis and overall survival of patients with tumors. Because miR-152 controls both the expression of 14-3-3β and HLA-G, it exerts a dual role in tumor cells by both altering the immunogenicity and the tumorigenicity.

Reduced immunosuppressive properties of axitinib in comparison with other tyrosine kinase inhibitors

The multikinase inhibitors sunitinib, sorafenib, and axitinib have an impact not only on tumor growth and angiogenesis, but also on the activity and function of immune effector cells. In this study, a comparative analysis of the growth inhibitory properties and apoptosis induction potentials of tyrosine kinase inhibitors on T cells was performed. Tyrosine kinase inhibitor treatment resulted in a dramatic decrease in T cell proliferation along with distinct impacts on the cell cycle progression. This was at least partially associated with an enhanced induction of apoptosis although triggered by distinct apoptotic mechanisms. In contrast to sunitinib and sorafenib, axitinib did not affect the mitochondrial membrane potential (Δψm) but resulted in an induction or stabilization of the induced myeloid leukemia cell differentiation protein (Mcl-1), leading to an irreversible arrest in the G2/M cell cycle phase and delayed apoptosis. Furthermore, the sorafenib-mediated suppression of immune effector cells, in particular the reduction of the CD8(+) T cell subset along with the down-regulation of key immune cell markers such as chemokine CC motif receptor 7 (CCR7), CD26, CD69, CD25, and CXCR3, was not observed in axitinib-treated immune effector cells. Therefore, axitinib rather than sorafenib seems to be suitable for implementation in complex treatment regimens of cancer patients including immunotherapy.

Abstract 2172: Effects of RAD001 on the protein expression pattern and function of tumor and immune cells

The crucial role of the PI3K/Akt/mTOR pathway in the pathogenesis of cancer has led to the development of various therapeutics targeting this signaling cascade. The serine/threonine kinase mTOR is involved in the regulation of the different growth properties of both tumor and immune cells. Furthermore, mTOR forms two macromolecular complexes: (i) the rapamycin-sensitive mTORC1, which contains RAPTOR and (ii) mTORC2, which is rapamycin-insensitive and contains RICTOR. Downstream targets of these complexes like HIF-1alpha and HIF-2alpha or cyclin D1 are responsible for the activation of various intracellular processes leading to the activation of cell proliferation, induction of angiogenesis, and metastasis. The effects of mTOR inhibitors have been most studied in T cells, although recently it has been shown that renal cell carcinoma (RCC) is tightly controlled by mTOR and that mTOR pathway activation represents an adverse prognostic factor. Thus targeted inhibition of mTOR represents a promising therapeutic approach for the treatment of RCC patients. Since it is currently discussed whether the RAD001-mediated effect on T cells might negatively interfere with its anti-tumoral activity in RCC we here analyzed the effects of RAD001 on the immune cell repertoire as well as the growth properties and protein expression pattern of RCC cells. We could show a decrease in the frequency of T cells which was associated with an altered expression of chemokines/ chemokine receptors suggesting an altered T cell homing. Furthermore, RAD001 exerts a dose-dependent growth inhibitory effect in RCC cells. This was accompanied by distinct expression levels of various proteins in RCC cells. So far, 11 differentially expressed proteins were identified by MALDI-TOF analysis, which are involved in cell proliferation and gene regulation. Currently functional analysis of RAD001-regulated proteins in T lymphocytes and RCC cells are performed providing better insights into the consequences of the mTOR inhibition.

Citation Format: Franziska Stehle, Kristin Schulz, Jana Kalich, Corinna Fahldieck, Barbara Seliger. Effects of RAD001 on the protein expression pattern and function of tumor and immune cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2172. doi:10.1158/1538-7445.AM2013-2172

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.

[Disposal of aerobic treated swine waste by refeeding to finishing swine (author's transl)]

Simple aerobic treatment of swine waste did not increase the production of microorganismprotein (pure protein). Addition of available energy resulted in a small increase of pure protein: During continuous aerobic treatment 20 g pure protein were produced by 100 g starch, during discontinuous aerobic treatment 10 g pure protein by 100 g organic matter from molasses (mean values). Comparative feeding trials with 90% resp. 80% feed restricted finishing swine without and with added swine waste (continuous treated without supplements resp. discontinuous treated with addition of yeasts and molasses) had as results no improvement in body-weight-gain but a 12% resp. 17% deterioration in feed conversion with 13% less bodyfat formation. Weight gains of both groups with restricted feed (without and with added swine waste) was 22% less in comparison to full fed swine. Losses at slaughter of swine in the group with feed restriction and added swine waste were partly due to higher intestine contents higher than that of swine with feed restriction and without added swine waste. Higher weights of livers and kidneys in swine of the "waste group" counts for a possibly higher metabolism-stress.

[Induction of tumors of the stomach in mini-pigs by methylnitrosourea administration (author's transl)]

The oncogenic effect of N-methyl-N-nitrosourea was studied in Hanford miniature-pig. The compound - dissolved in 0,9% NaC1 (pH 6,1 - 6,2) and supplemented with 1% NaH2PO4 - was administered per os to the animals in intervals of two weeks during 4,5 years. Finally the animals, which had behaved clinically inapparent during the whole run of the experiment, were sacrificed and autopsied. All animals of the experimental group had developed stomach tumours, whereas control animals showed normal conditions of gastric mucosa. Except one, all tumours were grouped macroscopically as multiple, exophytic, papillary, cauliflower-like neoplasms of the mucosa, located predominantly within cardia- and fundus-regions. Histologically they are to be classified generally aal characteristics of an early malign dedifferentiation. One - above excepted - tumour proably belongs to the class of malign neurinomas. The results of the experiment demonstrate in general that the obvious organotropic properties of certain oncogenic nitrosamides might be in a way also species-depending ones. This perception seems to be important in view of morphogenesis as well as of etiopathogenesis of stomach tumours.