Identification of a miRNA multi-targeting therapeutic strategy in glioblastoma

Glioblastoma (GBM) is a deadly and the most common primary brain tumor in adults. Due to their regulation of a high number of mRNA transcripts, microRNAs (miRNAs) are key molecules in the control of biological processes and are thereby promising therapeutic targets for GBM patients. In this regard, we recently reported miRNAs as strong modulators of GBM aggressiveness. Here, using an integrative and comprehensive analysis of the TCGA database and the transcriptome of GBM biopsies, we identified three critical and clinically relevant miRNAs for GBM, miR-17-3p, miR-222, and miR-340. In addition, we showed that the combinatorial modulation of three of these miRNAs efficiently inhibited several biological processes in patient-derived GBM cells of all these three GBM subtypes (Mesenchymal, Proneural, Classical), induced cell death, and delayed tumor growth in a mouse tumor model. Finally, in a doxycycline-inducible model, we observed a significant inhibition of GBM stem cell viability and a significant delay of orthotopic tumor growth. Collectively, our results reveal, for the first time, the potential of miR-17-3p, miR-222 and miR-340 multi-targeting as a promising therapeutic strategy for GBM patients.

Macropinocytosis requires Gal-3 in a subset of patient-derived glioblastoma stem cells

Recently, we involved the carbohydrate-binding protein Galectin-3 (Gal-3) as a druggable target for KRAS-mutant-addicted lung and pancreatic cancers. Here, using glioblastoma patient-derived stem cells (GSCs), we identify and characterize a subset of Gal-3high glioblastoma (GBM) tumors mainly within the mesenchymal subtype that are addicted to Gal-3-mediated macropinocytosis. Using both genetic and pharmacologic inhibition of Gal-3, we showed a significant decrease of GSC macropinocytosis activity, cell survival and invasion, in vitro and in vivo. Mechanistically, we demonstrate that Gal-3 binds to RAB10, a member of the RAS superfamily of small GTPases, and β1 integrin, which are both required for macropinocytosis activity and cell survival. Finally, by defining a Gal-3/macropinocytosis molecular signature, we could predict sensitivity to this dependency pathway and provide proof-of-principle for innovative therapeutic strategies to exploit this Achilles' heel for a significant and unique subset of GBM patients.

Phase I/II trial testing safety and immunogenicity of the multipeptide IMA950/poly-ICLC vaccine in newly diagnosed adult malignant astrocytoma patients

BACKGROUND

Peptide vaccines offer the opportunity to elicit glioma-specific T cells with tumor killing ability. Using antigens eluted from the surface of glioblastoma samples, we designed a phase I/II study to test safety and immunogenicity of the IMA950 multipeptide vaccine adjuvanted with poly-ICLC (polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose) in human leukocyte antigen A2+ glioma patients.

METHODS

Adult patients with newly diagnosed glioblastoma (n = 16) and grade III astrocytoma (n = 3) were treated with radiochemotherapy followed by IMA950/poly-ICLC vaccination. The first 6 patients received IMA950 (9 major histocompatibility complex [MHC] class I and 2 MHC class II peptides) intradermally and poly-ICLC intramuscularly (i.m.). After protocol amendment, IMA950 and poly-ICLC were mixed and injected subcutaneously (n = 7) or i.m. (n = 6). Primary endpoints were safety and immunogenicity. Secondary endpoints were overall survival, progression-free survival at 6 and 9 months, and vaccine-specific peripheral cluster of differentiation (CD)4 and CD8 T-cell responses.

RESULTS

The IMA950/poly-ICLC vaccine was safe and well tolerated. Four patients presented cerebral edema with rapid recovery. For the first 6 patients, vaccine-induced CD8 T-cell responses were restricted to a single peptide and CD4 responses were absent. After optimization of vaccine formulation, we observed multipeptide CD8 and sustained T helper 1 CD4 T-cell responses. For the entire cohort, CD8 T-cell responses to a single or multiple peptides were observed in 63.2% and 36.8% of patients, respectively. Median overall survival was 19 months for glioblastoma patients.

CONCLUSION

We provide, in a clinical trial, using cell surface-presented antigens, insights into optimization of vaccines generating effector T cells for glioma patients.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01920191.

Tracing anti-cancer and cancer-promoting actions of all-trans retinoic acid in breast cancer to a RARα epigenetic mechanism of mammary epithelial cell fate

A hallmark of cancer cells is the ability to evade the growth inhibitory/pro-apoptotic action of physiological all-trans retinoic acid (RA) signal, the bioactive derivative of Vitamin A. However, as we and others reported, RA can also promote cancer cell growth and invasion. Here we show that anticancer and cancer-promoting RA actions in breast cancer have roots in a mechanism of mammary epithelial cell morphogenesis that involves both transcriptional (epigenetic) and non-transcriptional RARα (RARA) functions. We found that the mammary epithelial cell-context specific degree of functionality of the RARA transcriptional (epigenetic) component of this mechanism, by tuning the effects of the non-transcriptional RARA component, determines different cell fate decisions during mammary morphogenesis. Indeed, factors that hamper the RARA epigenetic function make physiological RA drive aberrant morphogenesis via non-transcriptional RARA, thus leading to cell transformation. Remarkably, also the cell context-specific degree of functionality of the RARA epigenetic component retained by breast cancer cells is critical to determine cell fate decisions in response to physiological as well as supraphysiological RA variation. Overall this study supports the proof of principle that the epigenetic functional plasticity of the mammary epithelial cell RARA mechanism, which is essential for normal morphogenetic processes, is necessary to deter breast cancer onset/progression consequent to the insidious action of physiological RA.

Harnessing 3D models of mammary epithelial morphogenesis: An off the beaten path approach to identify candidate biomarkers of early stage breast cancer

Regardless of the etiological factor, an aberrant morphology is the common hallmark of ductal carcinoma in situ (DCIS), which is a highly heterogeneous disease. To test if critical core morphogenetic mechanisms are compromised by different mutations, we performed proteomics analysis of five mammary epithelial HME1 mutant lines that develop a DCIS-like morphology in three dimensional (3D) culture. Here we show first, that all HME1 mutant lines share a common protein signature highlighting an inverse deregulation of two annexins, ANXA2 and ANXA8. Either ANXA2 downregulation or ANXA8 upregulation in the HME1 cell context are per se sufficient to confer a 3D DCIS-like morphology. Seemingly, different mutations impinged on a common mechanism that differentially regulates the two annexins. Second, we show that ANXA8 expression is significantly higher in DCIS tissue samples versus normal breast tissue and atypical ductal hyperplasia (ADH). Apparently, ANXA8 expression is significantly more upregulated in ER-negative versus ER-positive cases, and significantly correlates with tumor stage, grade and positive lymph node. Based on our study, 3D mammary morphogenesis models can be an alternate/complementary strategy for unraveling new DCIS mechanisms and biomarkers.

Abstract 4203: Retinoic acid signal and annexins: A vicious circle of breast tumorigenesis

Physiological retinoic acid (RA), the bioactive derivative of Vitamin A, is a signal necessary for epithelial cell morphogenesis. During acinar morphogenesis of normal breast epithelial cells in three dimensional (3D) culture, physiological RA activates in a spatiotemporal fashion both genomic and non-genomic RA receptor alpha (RARA) signalings, thus leading to growth-arrested acini with a lumen lined by a layer of polarized cells. In contrast, lack of activation of genomic RARA by physiological RA results in the formation of 3D amorphous acini without lumen and with uncontrolled proliferation of the luminal cells. This is similar to what is observed in early in situ breast cancer lesions, such as ductal carcinoma in situ (DCIS). Different factors that, directly or indirectly, affect genomic RARA in normal breast epithelial cells and, consequently, the morphogenetic action of RA signal, lead to deregulation of members of the Annexin family, including Annexin A8 (ANXA8). Interestingly, upregulation of ANXA8 is sufficient to affect the genomic RARA-mediated RA signaling with consequent development of 3D amorphous acini. Thus, ANXA8 upregulation consequent to functional inhibition of genomic RARA by different factors seems to reinforce through a feedback loop the extent of functional inhibition of genomic RARA itself. It is of significance that ANXA8 upregulation in DCIS does correlate with tumor grade and stage.

Acknowledgements: Funding for this study was provided by the NCI R01 CA127614 grant, the Susan Komen Foundation, the Breast Cancer Coalition of Rochester, the Friends for an Earlier Breast Cancer Test, the Terri Brodeur Breast Cancer Foundation.

Citation Format: Stefano Rossetti, Wiam Bshara, Johanna Reiners, Francesca Corlazzoli, Austin Miller, Nicoletta Sacchi. Retinoic acid signal and annexins: A vicious circle of breast tumorigenesis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4203. doi:10.1158/1538-7445.AM2015-4203

Abstract 2497: Upregulation of annexin A8 is a common molecular phenotype of aberrant breast acinar morphogenesis induced by different genetic factors

It is estimated that up to 90% of women have benign breast lesions, some of which are pre-malignant. In situ lesions, particularly the ones that involve the ducts (ductal carcinoma in situ, DCIS), have the potential to progress into invasive malignant lesions and become life threatening. These breast premalignant states are identified because of specific morphological tissue abnormalities. Three-dimensional (3D) cultures of human mammary epithelial cells closely recapitulate breast acinar morphogenesis. While untransformed mammary epithelial cells form hollow acini, lined by polarized, non-proliferating cells, breast cancer cells form acini filled with non-polarized, actively proliferating cells, similar to DCIS. By using a proteomic approach in a panel of morphologically aberrant acini derived from human breast epithelial cells, we found that the disruption of acinar morphogenesis by different genetic factors generates a common proteomic signature. Among the proteins that we found consistently upregulated, we identified Annexin A8 (ANXA8), a member of the annexin family of calcium and membrane-binding proteins with a wide range of cellular functions, including cell division, apoptosis, and cell growth regulation. We tested ANXA8 expression in tissue samples from patients with atypical ductal hyperplasia (ADH), and tissue microarrays of DCIS, with or without, history of invasive breast cancer. Interestingly, this analysis detected ANXA8 increased expression in atypical proliferating ducts relative to non-proliferative ducts, making ANXA8 a potential marker of breast pre-malignancies.

Acknowledgments: this study was funded by grants of the Susan Komen Foundation, the Breast Cancer Coalition of Rochester, the Friends for an Earlier Test of Breast Cancer Foundation.

Citation Format: Stefano Rossetti, Francesca Corlazzoli, Nicoletta Sacchi. Upregulation of annexin A8 is a common molecular phenotype of aberrant breast acinar morphogenesis induced by different genetic factors. [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 2497. doi:10.1158/1538-7445.AM2013-2497

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

Abstract 3568: Induction of aberrant breast acinar morphogenesis by deregulation of an estrogen receptor alpha circadian circuit

Altered estrogen receptor alpha (ERA) signaling and altered circadian rhythms are both features of breast cancer. ERA mRNA oscillates in a circadian fashion in ERA-positive breast epithelial cells, but not in ERA-positive breast cancer cells (Rossetti et al., 2012a). Interestingly, we identified a circuit consisting of ERA and an estrogen-regulated loop consisting of PER2 and BMAL1, two circadian clock genes, in entrained ERA-positive breast epithelial cells. This estrogen-regulated circuit is apparently necessary for breast epithelial acinar morphogenesis, and its disruption by ERA knock down negatively affects both the estrogen-sustained circadian PER2-BMAL1mechanism and the formation of acini in three-dimensional (3D) culture on basement membrane. Conversely, knock down of either PER2 or BMAL1, by hampering the PER2-BMAL1 loop of the circadian clock, negatively affects both ERA circadian oscillations and 3D breast acinar morphogenesis (Rossetti et al., 2012b). This is the first evidence that a circuit comprising ERA and key circadian clock components is implicated in the acinar developmental processes of breast epithelial cells.

Acknowledgments: this work was supported by the Department of Defense (DOD) Concept Award W81XWH0610657 (NS), the Breast Cancer Coalition of Rochester (NS), and the Friends for an Earlier Test for Breast Cancer Foundation (NS).

Rossetti, S, Esposito, J, Corlazzoli, F, Gregorski, A, and Sacchi, N. (2012a). Entrainment of breast (cancer) epithelial cells detects distinct circadian oscillation patterns for clock and hormone receptor genes. Cell Cycle 11, 350-360.

Rossetti, S, Corlazzoli, F, Gregorski, A, Azmi, NH, and Sacchi, N. (2012b). Identification of an estrogen-regulated circadian mechanism necessary for breast acinar morphogenesis. Cell Cycle 11, 3691-3700.

Citation Format: Stefano Rossetti, Francesca Corlazzoli, Alex Gregorski, Nicoletta Sacchi. Induction of aberrant breast acinar morphogenesis by deregulation of an estrogen receptor alpha circadian circuit. [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 3568. doi:10.1158/1538-7445.AM2013-3568

Identification of an estrogen-regulated circadian mechanism necessary for breast acinar morphogenesis

Altered estrogen receptor α (ERA) signaling and altered circadian rhythms are both features of breast cancer. By using a method to entrain circadian oscillations in human cultured cells, we recently reported that the expression of key clock genes oscillates in a circadian fashion in ERA-positive breast epithelial cells but not in breast cancer cells, regardless of their ERA status. Moreover, we reported that ERA mRNA oscillates in a circadian fashion in ERA-positive breast epithelial cells, but not in ERA-positive breast cancer cells. By using ERA-positive HME1 breast epithelial cells, which can be both entrained in vitro and can form mammary gland-like acinar structures in three-dimensional (3D) culture, first we identified a circuit encompassing ERA and an estrogen-regulated loop consisting of two circadian clock genes, PER2 and BMAL1. Further, we demonstrated that this estrogen-regulated circuit is necessary for breast epithelial acinar morphogenesis. Disruption of this circuit due to ERA-knockdown, negatively affects the estrogen-sustained circadian PER2-BMAL1 mechanism as well as the formation of 3D HME1 acini. Conversely, knockdown of either PER2 or BMAL1, by hampering the PER2-BMAL1 loop of the circadian clock, negatively affects ERA circadian oscillations and 3D breast acinar morphogenesis. To our knowledge, this study provides the first evidence of the implication of an ERA-circadian clock mechanism in the breast acinar morphogenetic process.

Entrainment of breast (cancer) epithelial cells detects distinct circadian oscillation patterns for clock and hormone receptor genes

Most physiological and biological processes are regulated by endogenous circadian rhythms under the control of both a master clock, which acts systemically and individual cellular clocks, which act at the single cell level. The cellular clock is based on a network of core clock genes, which drive the circadian expression of non-clock genes involved in many cellular processes. Circadian deregulation of gene expression has emerged to be as important as deregulation of estrogen signaling in breast tumorigenesis. Whether there is a mutual deregulation of circadian and hormone signaling is the question that we address in this study. Here we show that, upon entrainment by serum shock, cultured human mammary epithelial cells maintain an inner circadian oscillator, with key clock genes oscillating in a circadian fashion. In the same cells, the expression of the estrogen receptor α (ER A) gene also oscillates in a circadian fashion. In contrast, ER A-positive and -negative breast cancer epithelial cells show disruption of the inner clock. Further, ER A-positive breast cancer cells do not display circadian oscillation of ER A expression. Our findings suggest that estrogen signaling could be affected not only in ER A-negative breast cancer, but also in ER A-positive breast cancer due to lack of circadian availability of ER A. Entrainment of the inner clock of breast epithelial cells, by taking into consideration the biological time component, provides a novel tool to test mechanistically whether defective circadian mechanisms can affect hormone signaling relevant to breast cancer.