Lactobacillus gasseri SF1183 Affects Intestinal Epithelial Cell Survival and Growth

It is now commonly accepted that the intestinal microbiota plays a crucial role in the gut physiology and homeostasis, and that both qualitative and quantitative alterations in the compositions of the gut flora exert profound effects on the host’s intestinal cells. In spite of this, the details of the interaction between commensal bacteria and intestinal cells are still largely unknown and only in few cases the molecular mechanisms have been elucidated. Here we analyze the effects of molecules produced and secreted by Lactobacillus gasseri SF1183 on human intestinal HCT116 cells. L. gasseri is a well known species of lactic acid bacteria, commonly associated to the human intestine and SF1183 is a human strain previously isolated from an ileal biopsy of an healthy volunteer. SF1183 produces and secretes, in a growth phase-dependent way, molecule(s) able to drastically interfere with HCT116 cell proliferation. Although several attempts to purify and identify the bioactive molecule(s) have been so far unsuccessful, a partial characterization has indicated that it is smaller than 3 kDa, thermostable and of proteinaceous nature. L. gasseri molecule(s) stimulate a G1-phase arrest of the cell cycle by up-regulation of p21WAF1 rendering cells protected from intrinsic and extrinsic apoptosis. A L. gasseri-mediated reduction of apoptosis and of cell proliferation could be relevant in protecting epithelial barrier integrity and helping in reconstituting tissutal homeostasis

Polyphenolic profile and targeted bioactivity of methanolic extracts from mediterranean ethnomedicinal plants on human cancer cell lines

The methanol extracts of the aerial part of four ethnomedicinal plants of Mediterranean region, two non-seed vascular plants, Equisetum hyemale L. and Phyllitis scolopendrium (L.) Newman, and two Spermatophyta, Juniperus communis L. (J. communis) and Cotinus coggygria Scop. (C. coggygria), were screened against four human cells lines (A549, MCF7, TK6 and U937). Only the extracts of J. communis and C. coggygria showed marked cytotoxic effects, affecting both cell morphology and growth. A dose-dependent effect of these two extracts was also observed on the cell cycle distribution. Incubation of all the cell lines in a medium containing J. communis extract determined a remarkable accumulation of cells in the G2/M phase, whereas the C. coggygria extract induced a significant increase in the percentage of G1 cells. The novelty of our findings stands on the observation that the two extracts, consistently, elicited coherent effects on the cell cycle in four cell lines, independently from their phenotype, as two of them have epithelial origin and grow adherent and two are lymphoblastoid and grow in suspension. Even the expression profiles of several proteins regulating cell cycle progression and cell death were affected by both extracts. LC-MS investigation of methanol extract of C. coggygria led to the identification of twelve flavonoids (compounds 1–11, 19) and eight polyphenols derivatives (12–18, 20), while in J. communis extract, eight flavonoids (21–28), a α-ionone glycoside (29) and a lignin (30) were found. Although many of these compounds have interesting individual biological activities, their natural blends seem to exert specific effects on the proliferation of cell lines either growing adherent or in suspension, suggesting potential use in fighting cancer

PO-038 PDGFRβ as a new biomarker for metastatic triple-negative breast cancer: development of a theranostic anti-PDGFRβ aptamer for imaging and suppression of metastases

Introduction Triple-negative breast cancers (TNBCs) are a heterogeneous group of aggressive tumours lacking oestrogen and progesterone receptors and HER2 receptor, thus excluding the possibility of using targeted therapy against these proteins. Mesenchymal-like (ML) subtype, characterised by a stem-like, undifferentiated phenotype, is more invasive and metastatic than other TNBC subtypes and has a strong tendency to form vasculogenic mimicry (VM). Recently, platelet derived growth factor receptor β (PDGFRβ) has been shown to play a role in VM of TNBC. Regrettably, therapies targeting PDGFRβ with tyrosine kinase inhibitors are not effective in treating TNBCs, thus developing new strategies to target PDGFRβ in TNBC patients is crucial to improve their chances of survival. Here, we describe the characterisation of the Gint4.T anti-PDGFRβ nuclease-resistant RNA aptamer as high efficacious theranostic tool for imaging and suppression of ML TNBC metastases. Material and methods Immunohistochemical analyses on a human TNBC tissue microarray was performed to correlate PDGFRβ expression with clinical and molecular features of different subtypes. Functional assays were conducted on PDGFRβ-positive ML BT-549 and MDA-MB-231 cells to investigate the effect of Gint4.T in interfering with cell growth in 3D conditions, migration, invasion and VM formation. Gint4.T was conjugated with near-infrared (NIR) fluorescent VivoTag-S680 and its binding specificity to receptor was confirmed both in vitro (confocal microscopy and flow cytometry analyses of TNBC cells) and in vivo (fluorescence molecular tomography in mice bearing TNBC xenografts). MDA-MB-231 cells were i.v. injected in nude mice and Gint4.T-NIR was used to detect lung metastases in mice untreated or i.v. injected with Gint4.T or a scrambled aptamer. Results and discussions The expression of PDGFRβ was observed in human TNBC samples characterised by higher metastatic behaviour. Treatment of TNBC cell lines with Gint4.T aptamer blocked their invasive growth and vasculogenic properties in 3D culture conditions, and strongly reduced cell migration/invasion in vitro and metastases formation in vivo. The Gint4.T-NIR was able to specifically bind to TNBC xenografts and detect lung metastases in vivo. Therefore, the aptamer revealed a high efficacious theranostic tool for imaging and suppression of TNBC metastases. Conclusion These studies indicate PDGFRβ as a new biomarker for ML and metastatic TNBC subtype and propose a novel targeting agent for the diagnosis and treatment of metastatic TNBCs

NGAL as a Potential Target in Tumor Microenvironment

The signaling network between cancer and stromal cells plays a crucial role in tumor microenvironment. The fate of tumor progression mainly depends on the huge amount of information that these cell populations exchange from the onset of neoplastic transformation. Interfering with such signaling has been producing exciting results in cancer therapy: just think of anti-PD-1/anti-PD-L1/anti-CTLA-4 antibodies that, acting as immune checkpoint inhibitors, interrupt the inhibitory signaling exerted by cancer cells on immune cells or the CAR-T technology that fosters the reactivation of anti-tumoral immunity in a restricted group of leukemias and lymphomas. Nevertheless, many types of cancers, in particular solid tumors, are still refractory to these treatments, so the identification of novel molecular targets in tumor secretome would benefit from implementation of current anti-cancer therapeutical strategies. Neutrophil Gelatinase-Associated Lipocalin (NGAL) is a secreted protein abundantly expressed in the secretome of various human tumors. It represents a promising target for the multiple roles that are played inside cancer and stromal cells, and also overall in their cross-talk. The review focuses on the different roles of NGAL in tumor microenvironment and in cancer senescence-associated secretory phenotype (SASP), highlighting the most crucial functions that could be eventually targetable in cancer therapy

Glutamine Metabolism in Cancer Stem Cells: A Complex Liaison in the Tumor Microenvironment

In this review we focus on the role of glutamine in control of cancer stem cell (CSC) fate. We first provide an overview of glutamine metabolism, and then summarize relevant studies investigating how glutamine metabolism modulates the CSC compartment, concentrating on solid tumors. We schematically describe how glutamine in CSC contributes to several metabolic pathways, such as redox metabolic pathways, ATP production, non-essential aminoacids and nucleotides biosynthesis, and ammonia production. Furthermore, we show that glutamine metabolism is a key regulator of epigenetic modifications in CSC. Finally, we briefly discuss how cancer-associated fibroblasts, adipocytes, and senescent cells in the tumor microenvironment may indirectly influence CSC fate by modulating glutamine availability. We aim to highlight the complexity of glutamine’s role in CSC, which supports our knowledge about metabolic heterogeneity within the CSC population

Glutamine Metabolism in Cancer Stem Cells: A Complex Liaison in the Tumor Microenvironment

In this review we focus on the role of glutamine in control of cancer stem cell (CSC) fate. We first provide an overview of glutamine metabolism, and then summarize relevant studies investigating how glutamine metabolism modulates the CSC compartment, concentrating on solid tumors. We schematically describe how glutamine in CSC contributes to several metabolic pathways, such as redox metabolic pathways, ATP production, non-essential aminoacids and nucleotides biosynthesis, and ammonia production. Furthermore, we show that glutamine metabolism is a key regulator of epigenetic modifications in CSC. Finally, we briefly discuss how cancer-associated fibroblasts, adipocytes, and senescent cells in the tumor microenvironment may indirectly influence CSC fate by modulating glutamine availability. We aim to highlight the complexity of glutamine’s role in CSC, which supports our knowledge about metabolic heterogeneity within the CSC population

The POZ/BTB and AT-Hook Containing Zinc Finger 1 (PATZ1) Transcription Regulator: Physiological Functions and Disease Involvement

PATZ1 is a zinc finger protein, belonging to the POZ domain Krüppel-like zinc finger (POK) family of architectural transcription factors, first discovered in 2000 by three independent groups. Since that time accumulating evidences have shown its involvement in a variety of biological processes (i.e., embryogenesis, stemness, apoptosis, senescence, proliferation, T-lymphocyte differentiation) and human diseases. Here we summarize these studies with a focus on the PATZ1 emerging and controversial role in cancer, where it acts as either a tumor suppressor or an oncogene. Finally, we give some insight on clinical perspectives using PATZ1 as a prognostic marker and therapeutic target

Human rpL3 induces p21-dependent G1/S arrest or apoptosis in Calu-6 cells

It is now largely accepted that ribosomal proteins may be implicated in a variety of biological functions besides that of components of the translation machinery. Many evidences show that a subset of ribosomal proteins are involved in the regulation of the cell cycle and apoptosis through modulation of p53 activity. In addition, p53-independent mechanisms of cell cycle arrest in response to alterations of ribosomal proteins availability have been described. Here, we identify human rpL3 as a new regulator of cell cycle and apoptosis through positive regulation of p21 expression in a p53-independent system. We demonstrate that the rpL3-mediated p21 upregulation requires the specific interaction between rpL3 and Sp1. Furthermore, in our experimental system, p21 overexpression leads to a dual outcome, activating the G1/S arrest of the cell cycle or the apoptotic pathway through mitochondria, depending on its intracellular levels. It is noteworthy that depletion of p21 abrogates both effects. The results of these experiments will be discussed