Abstract
Despite available aggressive treatment options, glioblastoma multiforme (GBM) has a median survival of 16 months indicating an urgent unmet need to develop new therapeutic strategies. ...Earlier, we have demonstrated that both glucose and acetate are the two major nutrients leading to synthesis of approximately ~60% acetyl-CoA in the brain tumors. Therefore, there must be other nutrients that may contribute to bioenergetic needs of highly proliferative GBM cells. Alanine is one of the non-essential amino acids (NEAA) that is constantly produced in cancer cells through Warburg glycolysis and its role in cancer metabolism is not well understood. Recently, it has been shown that alanine produced by pancreatic stellar cells contributed to the energy metabolism in pancreatic cancer cells. However, it is not known whether GBM can use alanine as an energy source. Here, we test whether GBM cells have the ability to metabolize alanine as a fuel to meet its increased energy requirements. Patient-derived GBM cells were cultured with 2.0 mM 3-13Calanine for the final 24 hours, harvested in 50% methanol, snap-frozen in liquid N2, freeze-thaw cycle 3 times and lysates were stored at -80 °C. Derivatized material from the frozen lysates were used for GC-MS analysis to determine carbon mass isotopomer distribution (MID) of various glycolytic and TCA cycle intermediates. Our results indicated that 3-13Calanine entered the GBM cells and produced 3-13Clactate via pyruvate. Also, alanine-derived 3-13Cpyruvate led to the generation of 2-13Cacetyl-CoA, which entered TCA cycle and produced M+1 13C isotopomers of citrate, glutamate, malate and aspartate. MID showed the following 13C enrichment (M+1) values: citrate, 6.9 % ± 0.3%; glutamate, 4.4% ± 0.3%; malate, 2.1% ± 0.6%; 2.1% ± 0.5%. This preliminary data shows that GBM cells are capable of utilizing alanine to generate energy and produce precursors for biomolecular synthesis.
With 3D genome mapping maturing over the past decade, studies exposed the differences between eukaryotic and prokaryotic genome organization. This raises the question of how the complex eukaryotic ...genome organization originated. Here, I explore potential pathways to answering this question, guided by our changing understanding of the origins of eukaryotes.
With 3D genome mapping maturing over the past decade, studies exposed the differences between eukaryotic and prokaryotic genome organization. This raises the question of how the complex eukaryotic genome organization originated. Here, I explore potential pathways to answering this question, guided by our changing understanding of the origins of eukaryotes.
Increased tissue stiffness is a classic characteristic of solid tumors. One of the major contributing factors is increased density of collagen fibers in the extracellular matrix (ECM). Here, we ...investigate how cancer cells biomechanically interact with and respond to the stiffness of the ECM. Probing the adaptability of cancer cells to altered ECM stiffness using optical tweezers-based microrheology and deformability cytometry, we find that only malignant cancer cells have the ability to adjust to collagen matrices of different densities. Employing microrheology on the biologically relevant spheroid invasion assay, we can furthermore demonstrate that, even within a cluster of cells of similar origin, there are differences in the intracellular biomechanical properties dependent on the cells' invasive behavior. We reveal a consistent increase of viscosity in cancer cells leading the invasion into the collagen matrices in comparison with cancer cells following in the stalk or remaining in the center of the spheroid. We hypothesize that this differential viscoelasticity might facilitate spheroid tip invasion through a dense matrix. These findings highlight the importance of the biomechanical interplay between cells and their microenvironment for tumor progression.
Intermediate filaments (IFs) are one of the three major elements of the cytoskeleton. Their stability, intrinsic mechanical properties, and cell type-specific expression patterns distinguish them ...from actin and microtubules. By providing mechanical support, IFs protect cells from external forces and participate in cell adhesion and tissue integrity. IFs form an extensive and elaborate network that connects the cell cortex to intracellular organelles. They act as a molecular scaffold that controls intracellular organization. However, IFs have been revealed as much more than just rigid structures. Their dynamics is regulated by multiple signaling cascades and appears to contribute to signaling events in response to cell stress and to dynamic cellular functions such as mitosis, apoptosis, and migration.
Autophagy is a fundamental biological process critical to all eukaryotic cellular life. Although autophagy has been increasingly studied, how its process is precisely coordinated remains an open ...question. ATG14 (ATG14L/Barkor) is known to play a crucial role in both autophagosome formation and autophagosome-lysosome fusion. However, how ATG14 is regulated, especially at the post-translation level, is still not clear. Here, we report that MARCH7 (membrane-associated ring-CH-type finger 7), an E3 ubiquitin ligase, inhibits autophagy by ubiquitinating ATG14. MARCH7 significantly promotes K6-, K11-, and K63-linked mixed polyubiquitination on ATG14, triggering the aggregation of ATG14 and reducing its solubility in cells. Functionally, we find that MARCH7 depletion decreases the number of aggresome-like induced structures (ALISs). Mechanistically, we show that ubiquitinated ATG14 has fewer interactions with STX17, leading to the inhibition of autophagy flux. Collectively, our study reveals a mechanism in regulating autophagy and suggests a potential strategy for the treatment of autophagy-related diseases.
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•Proteomics method identifies MARCH7 as an E3 ligase of ATG14•MARCH7 promotes K6-, K11-, and K63-linked mixed polyubiquitination on ATG14•MARCH7 inhibits autophagy flux via regulating the solubility of ATG14•Ubiquitination by MARCH7 impairs the interaction of ATG14 and STX17
Shi et al. describe an E3 ligase MARCH7 as an autophagy inhibitor that functions through the regulation of ubiquitination and the solubility of ATG14.
Long non-coding RNAs (lncRNAs) have emerged as promising novel modulators during osteogenesis in mesenchymal stem cells (MSCs). Enhanced SATB2 has been demonstrated to promote osteogenic ...differentiation of bone marrow-derived mesenchymal stem cells (hBMSCs) in patients with osteonecrosis. Preliminary bioinformatic analysis identified putative binding sites between microRNA-34c (miR-34c) and metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) or miR-34c and SATB2 3'UTR. Thus, the current study aimed to clarify the potential functional relevance of MALAT1-containing exosomes from BMSCs in osteoporosis. The extracted exosomes from primary BMSCs were co-cultured with human osteoblasts (hFOB1.19), followed by evaluation of the hFOB1.19 cell proliferation, alkaline phosphatase (ALP) activity and mineralized nodules. The obtained findings indicated that BMSC-Exos promoted the expression of SATB2 in osteoblasts, and SATB2 silencing reduced the ALP activity of osteoblasts and mineralized nodules. MALAT1 acted as a sponge of miR-34c to promote the expression of SATB2. Additionally, BMSCs-derived exosomal MALAT1 promoted osteoblast activity. Moreover,
experiments indicated that miR-34c reversed the effect of MALAT1, and SATB2 reversed the effect of miR-34c in ovariectomized mice. Taken together, this study demonstrates that BMSCs-derived exosomal MALAT1 enhances osteoblast activity in osteoporotic mice by mediating the miR-34c/SATB2 axis.
Harnessing an antitumor immune response has been a fundamental strategy in cancer immunotherapy. For over a century, efforts have primarily focused on amplifying immune activation mechanisms that are ...employed by humans to eliminate invaders such as viruses and bacteria. This “immune enhancement” strategy often results in rare objective responses and frequent immune-related adverse events (irAEs). However, in the last decade, cancer immunotherapies targeting the B7-H1/PD-1 pathway (anti-PD therapy), have achieved higher objective response rates in patients with much fewer irAEs. This more beneficial tumor response-to-toxicity profile stems from distinct mechanisms of action that restore tumor-induced immune deficiency selectively in the tumor microenvironment, here termed “immune normalization,” which has led to its FDA approval in more than 10 cancer indications and facilitated its combination with different therapies. In this article, we wish to highlight the principles of immune normalization and learn from it, with the ultimate goal to guide better designs for future cancer immunotherapies.
This Perspective discusses the concept of immune normalization and how its underlying principles may help to augment, as well as design, cancer immunotherapies.
NK cells are broadly distributed innate lymphoid cells (ILCs) encompassing distinct populations based on CD11b and CD27 expression in mice or CD56 intensity in humans. Involved in anti-viral and ...anti-tumor immunity thanks to their cytokines and chemokines secretion as well as their cytotoxic capabilities, NK cells have emerged as a promising therapeutic target in several solid tumors and hematological malignancies. To view this Snapshot, open or download the PDF.
NK cells are broadly distributed innate lymphoid cells (ILCs) encompassing distinct populations based on CD11b and CD27 expression in mice or CD56 intensity in humans. Involved in anti-viral and anti-tumor immunity thanks to their cytokines and chemokines secretion as well as their cytotoxic capabilities, NK cells have emerged as a promising therapeutic target in several solid tumors and hematological malignancies. To view this Snapshot, open or download the PDF.
We performed the first proteogenomic characterization of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) using paired tumor and adjacent liver tissues from 159 patients. Integrated ...proteogenomic analyses revealed consistency and discordance among multi-omics, activation status of key signaling pathways, and liver-specific metabolic reprogramming in HBV-related HCC. Proteomic profiling identified three subgroups associated with clinical and molecular attributes including patient survival, tumor thrombus, genetic profile, and the liver-specific proteome. These proteomic subgroups have distinct features in metabolic reprogramming, microenvironment dysregulation, cell proliferation, and potential therapeutics. Two prognostic biomarkers, PYCR2 and ADH1A, related to proteomic subgrouping and involved in HCC metabolic reprogramming, were identified. CTNNB1 and TP53 mutation-associated signaling and metabolic profiles were revealed, among which mutated CTNNB1-associated ALDOA phosphorylation was validated to promote glycolysis and cell proliferation. Our study provides a valuable resource that significantly expands the knowledge of HBV-related HCC and may eventually benefit clinical practice.
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•Proteomic subgroups stratify patient survival and allocate specific treatments•Alterations of the liver-specific proteome and metabolism in HCC are identified•Multi-omics profile of key signaling and metabolic pathways in HCC is depicted•CTNNB1 mutation-associated ALDOA phosphorylation promotes HCC cell proliferation
Proteogenomic characterization of HBV-related hepatocellular carcinoma (HCC) using paired tumor and adjacent liver tissues identifies three subgroups with distinct features in metabolic reprogramming, microenvironment dysregulation, cell proliferation, and potential therapeutics.
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