Cells, Volume 9, Issue 10 (October 2020) – 193 articles

Mineral trioxide aggregate (MTA) was introduced as a material for dental endodontic regenerative therapy. Here, we show the dynamics of living dental pulp cells in direct contact with an MTA disk. A red fluorescence protein (DsRed) was introduced into immortalized porcine dental pulp cells (PPU7) and cloned. DsRed-PPU7 cells were cultured on the MTA disk and cell proliferation, chemotaxis, the effects of growth factors and the gene expression of cells were investigated at the biological, histomorphological and genetic cell levels. Mineralized precipitates formed in the DsRed-PPU7 cells were characterized with crystal structural analysis. DsRed-PPU7 cells proliferated in the central part of the MTA disk until Day 6 and displayed a tendency to move to the outer circumference. Both transforming growth factor beta and bone morphogenetic protein promoted the proliferation and movement of DsRed-PPU7 cells and also enhanced the expression levels of odontoblastic gene differentiation markers. Mineralized precipitates formed in DsRed-PPU7 were composed of calcium and phosphate but its crystals were different in each position. Our investigation showed that DsRed-PPU7 cells in direct contact with the MTA disk could differentiate into odontoblasts by controlling cell–cell and cell–substrate interactions depending on cell adhesion and the surrounding environment of the MTA. Full article

Human African trypanosomiasis (HAT) is caused by Trypanosoma brucei parasites. The T. brucei aquaglyceroporin isoform 2, TbAQP2, has been linked to the uptake of pentamidine. Negative membrane potentials and transmembrane pH gradients were suggested to promote transport of the dicationic antitrypanosomal drug. Application of ionophores to trypanosomes further hinted at direct inhibition of TbAQP2 by carbonyl cyanide m-chlorophenyl hydrazone (CCCP). Here, we tested for direct effects of three classical ionophores (CCCP, nigericin, gramicidin) on the functionality of TbAQP2 and the related TbAQP3 at conditions that are independent from the membrane potential or a proton gradient. We expressed TbAQP2 and TbAQP3 in yeast, and determined permeability of uncharged glycerol at neutral pH using stopped-flow light scattering. The mobile proton carrier CCCP directly inhibited TbAQP2 glycerol permeability at an IC₅₀ of 2 µM, and TbAQP3 to a much lesser extent (IC₅₀ around 1 mM) likely due to different selectivity filter layouts. Nigericin, another mobile carrier, left both isoforms unaffected. The membrane-integral pore-forming gramicidin evenly inhibited TbAQP2 and TbAQP2 in the double-digit micromolar range. Our data exemplify the need for suitable controls to detect unwanted ionophore side effects even when used at concentrations that are typically recommended to disturb the transmembrane ion distribution. Full article

Molecular imaging plays an increasingly important role in the diagnosis and treatment of different malignancies. Radiolabeled probes enable the visualization of the primary tumor as well as the metastases and have been also employed in targeted therapy and theranostic approaches. With breast cancer being the most common malignancy in women worldwide it is of special interest to develop novel targeted treatments. However, tumor microenvironment and escape mechanisms often limit their therapeutic potential. Addressing tumor stroma associated targets provides a promising option to inhibit tumor growth and angiogenesis and to disrupt tumor tissue architecture. This review describes recent developments on radiolabeled probes used in diagnosis and treatment of breast cancer especially in triple negative type with the focus on potential targets offered by the tumor microenvironment, like tumor associated macrophages, cancer associated fibroblasts, and endothelial cells. Full article

Tafazzin is a phospholipid transacylase that catalyzes the remodeling of cardiolipin, a mitochondrial phospholipid required for oxidative phosphorylation. Mutations of the tafazzin gene cause Barth syndrome, which is characterized by mitochondrial dysfunction and dilated cardiomyopathy, leading to premature death. However, the molecular mechanisms underlying the cause of mitochondrial dysfunction in Barth syndrome remain poorly understood. We again highlight the fact that the tafazzin deficiency is also linked to defective oxidative phosphorylation associated with oxidative stress. All the mitochondrial events are positioned in a context where mitophagy is a key element in mitochondrial quality control. Here, we investigated the role of tafazzin in mitochondrial homeostasis dysregulation and mitophagy alteration. Using a HeLa cell model of tafazzin deficiency, we show that dysregulation of tafazzin in HeLa cells induces alteration of mitophagy. Our findings provide some additional insights into mitochondrial dysfunction associated with Barth syndrome, but also show that mitophagy inhibition is concomitant with apoptosis dysfunction through the inability of abnormal mitochondrial cardiolipin to assume its role in cytoplasmic signal transduction. Our work raises hope that pharmacological manipulation of the mitophagic pathway together with mitochondrially targeted antioxidants may provide new insights leading to promising treatment for these highly lethal conditions. Full article

The synthetic polymer, polyallylamine hydrochloride (PAA), is found in a variety of applications in biotechnology and medicine. It is used in gene and siRNA transfer, to form microcapsules for targeted drug delivery to damaged and tumor cells. Conventional chemotherapy often does not kill all cancer cells and leads to multidrug resistance (MDR). Until recently, studies of the effects of PAA on cells have mainly focused on their morphological and genetic characteristics immediately or several hours after exposure to the polymer. The properties of the cell progeny which survived the sublethal effects of PAA and resumed their proliferation, were not monitored. The present study demonstrated that treatment of immortalized Chinese hamster cells CHLV-79 RJK sensitive (RJK) and resistant (RJKEB) to ethidium bromide (EB) with cytotoxic doses of PAA, selected cells with increased karyotypic instability, were accompanied by changes in the expression of p53 genes c-fos, topo2-α, hsp90, hsc70. These changes did not contribute to the progression of MDR, accompanied by the increased sensitivity of these cells to the toxic effects of doxorubicin (DOX). Our results showed that PAA does not increase the oncogenic potential of immortalized cells and confirmed that it can be used for intracellular drug delivery for anticancer therapy. Full article

Growth hormone-releasing hormone (GHRH) is secreted primarily from the hypothalamus, but other tissues, including the lungs, produce it locally. GHRH stimulates the release and secretion of growth hormone (GH) by the pituitary and regulates the production of GH and hepatic insulin-like growth factor-1 (IGF-1). Pituitary-type GHRH-receptors (GHRH-R) are expressed in human lungs, indicating that GHRH or GH could participate in lung development, growth, and repair. GHRH-R antagonists (i.e., synthetic peptides), which we have tested in various models, exert growth-inhibitory effects in lung cancer cells in vitro and in vivo in addition to having anti-inflammatory, anti-oxidative, and pro-apoptotic effects. One antagonist of the GHRH-R used in recent studies reviewed here, MIA-602, lessens both inflammation and fibrosis in a mouse model of bleomycin lung injury. GHRH and its peptide agonists regulate the proliferation of fibroblasts through the modulation of extracellular signal-regulated kinase (ERK) and Akt pathways. In addition to downregulating GH and IGF-1, GHRH-R antagonist MIA-602 inhibits signaling pathways relevant to inflammation, including p21-activated kinase 1-signal transducer and activator of transcription 3/nuclear factor-kappa B (PAK1-STAT3/NF-κB and ERK). MIA-602 induces fibroblast apoptosis in a dose-dependent manner, which is an effect that is likely important in antifibrotic actions. Taken together, the novel data reviewed here show that GHRH is an important peptide that participates in lung homeostasis, inflammation, wound healing, and cancer; and GHRH-R antagonists may have therapeutic potential in lung diseases. Full article

Cold atmospheric plasma (CAP) is a promising new agent for (selective) cancer treatment, but the underlying cause of the anti-cancer effect of CAP is not well understood yet. Among different theories and observations, one theory in particular has been postulated in great detail and consists of a very complex network of reactions that are claimed to account for the anti-cancer effect of CAP. Here, the key concept is a reactivation of two specific apoptotic cell signaling pathways through catalase inactivation caused by CAP. Thus, it is postulated that the anti-cancer effect of CAP is due to its ability to inactivate catalase, either directly or indirectly. A theoretical investigation of the proposed theory, especially the role of catalase inactivation, can contribute to the understanding of the underlying cause of the anti-cancer effect of CAP. In the present study, we develop a mathematical model to analyze the proposed catalase-dependent anti-cancer effect of CAP. Our results show that a catalase-dependent reactivation of the two apoptotic pathways of interest is unlikely to contribute to the observed anti-cancer effect of CAP. Thus, we believe that other theories of the underlying cause should be considered and evaluated to gain knowledge about the principles of CAP-induced cancer cell death. Full article

Black spot disease, caused by Alternaria brassicicola in Brassica species, is one of the most devastating diseases all over the world, especially since there is no known fully resistant Brassica cultivar. In this study, the visualization of black spot disease development on Brassica oleracea var. capitata f. alba (white cabbage) leaves and subsequent ultrastructural, molecular and physiological investigations were conducted. Inter- and intracellular hyphae growth within leaf tissues led to the loss of host cell integrity and various levels of organelle disintegration. Severe symptoms of chloroplast damage included the degeneration of chloroplast envelope and grana, and the loss of electron denseness by stroma at the advanced stage of infection. Transcriptional profiling of infected leaves revealed that photosynthesis was the most negatively regulated biological process. However, in infected leaves, chlorophyll and carotenoid content did not decrease until 48 hpi, and several chlorophyll a fluorescence parameters, such as photosystem II quantum yield (F_v/F_m), non-photochemical quenching (NPQ), or plant vitality parameter (Rdf) decreased significantly at 24 and 48 hpi compared to control leaves. Our results indicate that the initial stages of interaction between B. oleracea and A. brassicicola are not uniform within an inoculation site and show a complexity of host responses and fungal attempts to overcome host cell defense mechanisms. The downregulation of photosynthesis at the early stage of this susceptible interaction suggests that it may be a part of a host defense strategy, or, alternatively, that chloroplasts are targets for the unknown virulence factor(s) of A. brassicicola. However, the observed decrease of photosynthetic efficiency at the later stages of infection is a result of the fungus-induced necrotic lesion expansion. Full article

The phosphopeptide P140/Lupuzor, which improves the course of lupus disease in mice and patients, targets chaperone-mediated autophagy (CMA), a selective form of autophagy that is abnormally upregulated in lupus-prone MRL/lpr mice. Administered intravenously to diseased mice, P140 reduces the expression level of two major protein players of CMA, LAMP2A and HSPA8, and inhibits CMA in vitro in a cell line that stably expresses a CMA reporter. Here, we aimed to demonstrate that P140 also affects CMA in vivo and to unravel the precise cellular mechanism of how P140 interacts with the CMA process. MRL/lpr mice and CBA/J mice used as control received P140 or control peptides intravenously. Lysosome-enriched fractions of spleen or liver were prepared to examine lysosomal function. Highly purified lysosomes were further isolated and left to incubate with the CMA substrate to study at which cellular step P140 interacts with the CMA process. The data show that P140 effectively regulates CMA in vivo in MRL/lpr mice at the step of substrate lysosomal uptake and restores some alterations of defective lysosomes. For the first time, it is demonstrated that by occluding the intralysosome uptake of CMA substrates, a therapeutic molecule can attenuate excessive CMA activity in a pathological pro-inflammatory context and protect against hyperinflammation. This recovery effect of P140 on hyperactivated CMA is not only important for lupus therapy but potentially also for treating other (auto)inflammatory diseases, including neurologic and metabolic disorders, where CMA modulation would be highly beneficial. Full article

Adipose tissue is contemplated as a dynamic organ that plays key roles in the human body. Adipogenesis is the process by which adipocytes develop from adipose-derived stem cells to form the adipose tissue. Adipose-derived stem cells’ differentiation serves well beyond the simple goal of producing new adipocytes. Indeed, with the current immense biotechnological advances, the most critical role of adipose-derived stem cells remains their tremendous potential in the field of regenerative medicine. This review focuses on examining the physiological importance of adipogenesis, the current approaches that are employed to model this tightly controlled phenomenon, and the crucial role of adipogenesis in elucidating the pathophysiology and potential treatment modalities of human diseases. The future of adipogenesis is centered around its crucial role in regenerative and personalized medicine. Full article

BCL-2 interacting cell death suppressor (BIS), also known as BAG3, is a multifunctional protein. Aberrant expression and mutation of BIS have been implicated in cancers and myopathy. However, there have only been a few studies on the splicing of BIS pre-mRNA. In the present study, through RT-PCR and sequencing in various cell lines and mouse tissues, we identified for the first time the presence of BIS mRNA isomers in which exon 3 or exons 2–3 are skipped. We also demonstrated that the depletion of SRSF3 promoted the skipping of exon 3 of BIS pre-mRNA in endogenous BIS and the GFP-BIS minigene. SRSF3 specifically interacts with the putative binding sites in exon 3, in which deletion promoted the skipping of exon 3 in the GFP-BIS minigene, which was comparable to the effect of SRSF knockdown. Even though acceleration of exon 3 skipping was not observed in response to various stimuli, SRSF3 depletion, accompanied by the production of a truncated BIS protein, inhibited the nuclear translocation of HSF1, which was restored by the wild-type BIS, not by exon 3-depleted BIS. Therefore, our results suggested that the maintenance of SRSF3 levels and subsequent preservation of the intact BIS protein is an important factor in modulating HSF1 localization upon cellular stress. Full article

Our previous studies identified that retinal endothelial damage caused by hyperglycemia or nucleoside diphosphate kinase-B (NDPK-B) deficiency is linked to elevation of angiopoietin-2 (Ang-2) and the activation of the hexosamine biosynthesis pathway (HBP). Herein, we investigated how NDPK-B is involved in the HBP in endothelial cells (ECs). The activities of NDPK-B and O-GlcNAcase (OGA) were measured by in vitro assays. Nucleotide metabolism and O-GlcNAcylated proteins were assessed by UPLC-PDA (Ultra-performance liquid chromatography with Photodiode array detection) and immunoblot, respectively. Re-expression of NDPK-B was achieved with recombinant adenoviruses. Our results show that NDPK-B depletion in ECs elevated UDP-GlcNAc levels and reduced NDPK activity, similar to high glucose (HG) treatment. Moreover, the expression and phosphorylation of glutamine:fructose-6-phosphate amidotransferase (GFAT) were induced, whereas OGA activity was suppressed. Furthermore, overall protein O-GlcNAcylation, along with O-GlcNAcylated Ang-2, was increased in NDPK-B depleted ECs. Pharmacological elevation of protein O-GlcNAcylation using Thiamet G (TMG) or OGA siRNA increased Ang-2 levels. However, the nucleoside triphosphate to diphosphate (NTP/NDP) transphosphorylase and histidine kinase activity of NDPK-B were dispensable for protein O-GlcNAcylation. NDPK-B deficiency hence results in the activation of HBP and the suppression of OGA activity, leading to increased protein O-GlcNAcylation and further upregulation of Ang-2. The data indicate a critical role of NDPK-B in endothelial damage via the modulation of the HBP. Full article

Neurosteroids are steroids synthetized in the nervous system, with the first step of steroidogenesis taking place within mitochondria with the synthesis of pregnenolone. They exert important brain-specific functions by playing a role in neurotransmission, learning and memory processes, and neuroprotection. Here, we show for the first time that mitochondrial neurosteroidogenesis follows a circadian rhythm and correlates with the rhythmic changes in mitochondrial morphology. We used synchronized human A172 glioma cells, which are steroidogenic cells with a functional core molecular clock, to show that pregnenolone levels and translocator protein (TSPO) are controlled by the clock, probably via circadian regulation of mitochondrial fusion/fission. Key findings were recapitulated in mouse brains. We also showed that genetic or pharmacological abrogation of fusion/fission activity, as well as disturbing the core molecular clock, abolished circadian rhythms of pregnenolone and TSPO. Our findings provide new insights into the crosstalk between mitochondrial function (here, neurosteroidogenesis) and circadian cycles. Full article

Coronaviruses are able to establish persistence. However, how coronaviruses react to persistence and whether the selected viruses have altered their characteristics remain unclear. In this study, we found that the persistent infection of bovine coronavirus (BCoV), which is in the same genus as SARS-COV-2, led to alterations of genome structure, attenuation of gene expression, and the synthesis of subgenomic mRNA (sgmRNA) with a previously unidentified pattern. Subsequent analyses revealed that the altered genome structures were associated with the attenuation of gene expression. In addition, the genome structure at the 5′ terminus and the cellular environment during the persistence were responsible for the sgmRNA synthesis, solving the previously unanswered question regarding the selection of transcription regulatory sequence for synthesis of BCoV sgmRNA 12.7. Although the BCoV variants (BCoV-p95) selected under the persistence replicated efficiently in cells without persistent infection, its pathogenicity was still lower than that of wild-type (wt) BCoV. Furthermore, in comparison with wt BCoV, the variant BCoV-p95 was not able to efficiently adapt to the challenges of alternative environments, suggesting wt BCoV is genetically robust. We anticipate that the findings derived from this fundamental research can contribute to the disease control and treatments against coronavirus infection including SARS-CoV-2. Full article

Chronic liver diseases (CLD) represent a worldwide health problem. While CLDs may have diverse etiologies, a common pathogenic denominator is the presence of liver fibrosis. Cirrhosis, the end-stage of CLD, is characterized by extensive fibrosis and is markedly associated with the development of hepatocellular carcinoma. The most important event in hepatic fibrogenesis is the activation of hepatic stellate cells (HSC) following liver injury. Activated HSCs acquire a myofibroblast-like phenotype becoming proliferative, fibrogenic, and contractile cells. While transient activation of HSCs is part of the physiological mechanisms of tissue repair, protracted activation of a wound healing reaction leads to organ fibrosis. The phenotypic changes of activated HSCs involve epigenetic mechanisms mediated by non-coding RNAs (ncRNA) as well as by changes in DNA methylation and histone modifications. During CLD these epigenetic mechanisms become deregulated, with alterations in the expression and activity of epigenetic modulators. Here we provide an overview of the epigenetic alterations involved in fibrogenic HSCs transdifferentiation with particular focus on histones acetylation changes. We also discuss recent studies supporting the promising therapeutic potential of histone deacetylase inhibitors in liver fibrosis. Full article

Activity-dependent neuroprotective protein (ADNP) mutations are linked with cognitive dysfunctions characterizing the autistic-like ADNP syndrome patients, who also suffer from delayed motor maturation. We thus hypothesized that ADNP is deregulated in versatile myopathies and that local ADNP muscle deficiency results in myopathy, treatable by the ADNP fragment NAP. Here, single-cell transcriptomics identified ADNP as a major constituent of the developing human muscle. ADNP transcript concentrations further predicted multiple human muscle diseases, with concentrations negatively correlated with the ADNP target interacting protein, microtubule end protein 1 (EB1). Reverting back to modeling at the single-cell level of the male mouse transcriptome, Adnp mRNA concentrations age-dependently correlated with motor disease as well as with sexual maturation gene transcripts, while Adnp expressing limb muscle cells significantly decreased with aging. Mouse Adnp heterozygous deficiency exhibited muscle microtubule reduction and myosin light chain (Myl2) deregulation coupled with motor dysfunction. CRISPR knockdown of adult gastrocnemius muscle Adnp in a Cas9 mouse resulted in treadmill (male) and gait (female) dysfunctions that were specifically ameliorated by treatment with the ADNP snippet, microtubule interacting, Myl2—regulating, NAP (CP201). Taken together, our studies provide new hope for personalized diagnosis/therapeutics in versatile myopathies. Full article

Plant cell walls play an important role in shaping the defense strategies of plants. This research demonstrates the influence of two differentiators: the lifestyle and properties of the Trichoderma species on cell wall changes in common wheat seedlings. The methodologies used in this investigation include microscopy observations and immunodetection. In this study was shown that the plant cell wall was altered due to its interaction with Trichoderma. The accumulation of lignins and reorganization of pectin were observed. The immunocytochemistry indicated that low methyl-esterified pectins appeared in intercellular spaces. Moreover, it was found that the arabinogalactan protein epitope JIM14 can play a role in the interaction of wheat roots with both the tested Trichoderma strains. Nevertheless, we postulate that modifications, such as the appearance of lignins, rearrangement of low methyl-esterified pectins, and arabinogalactan proteins due to the interaction with Trichoderma show that tested strains can be potentially used in wheat seedlings protection to pathogens. Full article

Myelodysplastic syndromes are a group of clonal diseases of hematopoietic stem cells and are characterized by multilineage dysplasia, ineffective hematopoiesis, peripheral blood cytopenias, genetic instability and a risk of transformation to acute myeloid leukemia. Some patients with non-Hodgkin lymphomas (NHLs) may have developed secondary myelodysplasia before therapy. Bone marrow (BM) hematopoiesis is regulated by a spectrum of epigenetic factors, among which microRNAs (miRNAs) are special. The aim of this work is to profile miRNA expression in BM cells in untreated NHL patients with secondary myelodysplasia. A comparative analysis of miRNA expression levels between the NHL and non-cancer blood disorders samples revealed that let-7a-5p was upregulated, and miR-26a-5p, miR-199b-5p, miR-145-5p and miR-150-5p were downregulated in NHL with myelodysplasia (p < 0.05). We for the first time developed a profile of miRNA expression in BM samples in untreated NHL patients with secondary myelodysplasia. It can be assumed that the differential diagnosis for blood cancers and secondary BM conditions based on miRNA expression profiles will improve the accuracy and relevance of the early diagnosis of cancerous and precancerous lesions in BM. Full article

The incidence and prevalence of cardiac diseases, which are the main cause of death worldwide, are likely to increase because of population ageing and changes in lifestyle. Prevailing theories about the mechanisms of cardiac disease onset feature the gradual derailment of cellular protein homeostasis (proteostasis) and loss of the protein quality control as central factors. In the heart, loss of protein patency, due to flaws in design (genetically) or environmentally-induced wear and tear, may overwhelm protein quality control, thereby triggering derailment of proteostasis and contributing to cardiac disease onset. Full article

Hedgehog (Hh) signaling and mTOR signaling, essential for embryonic development and cellular metabolism, are both coordinated by the primary cilium. Observations from cancer cells strongly indicate crosstalk between Hh and mTOR signaling. This hypothesis is supported by several studies: Evidence points to a TGFβ-mediated crosstalk; Increased PI3K/AKT/mTOR activity leads to increased Hh signaling through regulation of the GLI transcription factors; increased Hh signaling regulates mTORC1 activity positively by upregulating NKX2.2, leading to downregulation of negative mTOR regulators; GSK3 and AMPK are, as members of both signaling pathways, potentially important links between Hh and mTORC1 signaling; The kinase DYRK2 regulates Hh positively and mTORC1 signaling negatively. In contrast, both positive and negative regulation of Hh has been observed for DYRK1A and DYRK1B, which both regulate mTORC1 signaling positively. Based on crosstalk observed between cilia, Hh, and mTORC1, we suggest that the interaction between Hh and mTORC1 is more widespread than it appears from our current knowledge. Although many studies focusing on crosstalk have been carried out, contradictory observations appear and the interplay involving multiple partners is far from solved. Full article

Macroautophagy is a conserved degradative process for maintaining cellular homeostasis and plays a key role in aging and various human disorders. The microtubule-associated protein 1A/1B light chain 3B (MAP1LC3B or LC3B) is commonly analyzed as a key marker for autophagosomes and as a proxy for autophagic flux. Three paralogues of the LC3 gene exist in humans: LC3A, LC3B and LC3C. The molecular function, regulation and cellular localization of LC3A and LC3C have not been investigated frequently, even if a similar function to that described for LC3B appears likely. Here, we have selectively decapacitated LC3B by three separate strategies in primary human fibroblasts and analyzed the evoked effects on LC3A, LC3B and LC3C in terms of their cellular distribution and co-localization with p62, a ubiquitin and autophagy receptor. First, treatment with pharmacological sirtuin 1 (SIRT1) inhibitors to prevent the translocation of LC3B from the nucleus into the cytosol induced an increase in cytosolic LC3C, a heightened co-localization of LC3C with p62, and an increase LC3C-dependent autophagic flux as assessed by protein lipidation. Cytosolic LC3A, however, was moderately reduced, but also more co-localized with p62. Second, siRNA-based knock-down of SIRT1 broadly reproduced these findings and increased the co-localization of LC3A and particularly LC3C with p62 in presumed autophagosomes. These effects resembled the effects of pharmacological sirtuin inhibition under normal and starvation conditions. Third, siRNA-based knock-down of total LC3B in cytosol and nucleus also induced a redistribution of LC3C as if to replace LC3B in the nucleus, but only moderately affected LC3A. Total protein expression of LC3A, LC3B, LC3C, GABARAP and GABARAP-L1 following LC3B decapacitation was unaltered. Our data indicate that nuclear trapping and other causes of LC3B functional loss in the cytosol are buffered by LC3A and actively compensated by LC3C, but not by GABARAPs. The biological relevance of the potential functional compensation of LC3B decapacitation by LC3C and LC3A warrants further study. Full article

The endoplasmic reticulum (ER) has emerged as a source of hydrogen peroxide (H₂O₂) and a hub for peroxide-based signaling events. Here we outline cellular sources of ER-localized peroxide, including sources within and near the ER. Focusing on three ER-localized proteins—the molecular chaperone BiP, the transmembrane stress-sensor IRE1, and the calcium pump SERCA2—we discuss how post-translational modification of protein cysteines by H₂O₂ can alter ER activities. We review how changed activities for these three proteins upon oxidation can modulate signaling events, and also how cysteine oxidation can serve to limit the cellular damage that is most often associated with elevated peroxide levels. Full article

Anti-Müllerian hormone (AMH) is responsible for the Müllerian ducts’ regression in male fetuses. In cells of cancers with AMH receptors (AMHRII), AMH induces cell cycle arrest or apoptosis. As AMH occurs naturally and does not exhibit significant side effects while reducing neoplastic cell colonies, it can be considered as a potential therapeutic agent for cancer treatment. The purpose of this study was to assess the AMHRII expression in endometrial cancer (EC) in correlation to various demographic data and clinical conditions. Immunohistochemical analysis was used to assess AMHRII expression in EC tissue samples retrieved from 230 women with pre-cancerous state of endometrium (PCS) and EC. AMHRII was detected in 100% of samples. No statistical difference was observed for AMHRII expression depending on the histopathological type of EC, cancer staging, body mass index, and age, as well as the number of years of menstruation, births and miscarriages, and average and total breastfeeding time. Diabetes mellitus type 2 is the only factor that has an impact on AMHRII expression in EC tissue. Thus, this study supports the idea of theoretical use of AMH in EC treatment because all histopathological types of EC at all stages of advancement present receptors for AMH. Full article

One third of all human proteins are either transmembrane or soluble secretory proteins that first target the endoplasmic reticulum (ER). These proteins subsequently leave the ER and enter the Golgi apparatus via ER-Golgi intermediate vesicular structures. Live-cell imaging of cargos fused to fluorescent proteins (FPs) enables the high-resolution visualization and characterization of secretory transport processes. Here, we performed fluorescence time-lapse imaging to assess the Ca²⁺ and energy dependency of ER-to-Golgi transport in living HeLa cells, a cancer cell model which has been well investigated. Our data revealed that ER-to-Golgi transport remained highly efficient in the absence of ATP-generating substrates, despite clear reductions in cytosolic and mitochondrial ATP levels under these energy stress conditions. However, cell treatment with 2-deoxy-D-glucose (2-DG), which severely diminished subcellular ATP levels, abolished ER-to-Golgi transport. Interestingly, while 2-DG elevated cytosolic Ca²⁺ levels and reduced long-distance movements of glycosylphosphatidylinositol (GPI)-positive vesicles, robust short-term ER Ca²⁺ mobilizations, which strongly affected the motility of these vesicles, did not considerably impair ER-to-Golgi transport. In summary, we highlight that ER-to-Golgi transport in HeLa cells remains functional despite high energy and Ca²⁺ stress levels. Full article

Up to 18% of patients with acute myeloid leukemia (AML) present with a white blood cell (WBC) count of greater than 100,000/µL, a condition that is frequently referred to as hyperleukocytosis. Hyperleukocytosis has been associated with an adverse prognosis and a higher incidence of life-threatening complications such as leukostasis, disseminated intravascular coagulation (DIC), and tumor lysis syndrome (TLS). The molecular processes underlying hyperleukocytosis have not been fully elucidated yet. However, the interactions between leukemic blasts and endothelial cells leading to leukostasis and DIC as well as the processes in the bone marrow microenvironment leading to the massive entry of leukemic blasts into the peripheral blood are becoming increasingly understood. Leukemic blasts interact with endothelial cells via cell adhesion molecules such as various members of the selectin family which are upregulated via inflammatory cytokines released by leukemic blasts. Besides their role in the development of leukostasis, cell adhesion molecules have also been implicated in leukemic stem cell survival and chemotherapy resistance and can be therapeutically targeted with specific inhibitors such as plerixafor or GMI-1271 (uproleselan). However, in the absence of approved targeted therapies supportive treatment with the uric acid lowering agents allopurinol and rasburicase as well as aggressive intravenous fluid hydration for the treatment and prophylaxis of TLS, transfusion of blood products for the management of DIC, and cytoreduction with intensive chemotherapy, leukapheresis, or hydroxyurea remain the mainstay of therapy for AML patients with hyperleukocytosis. Full article

Aberrant metabolism is a major hallmark of cancer. Abnormal cancer metabolism, such as aerobic glycolysis and increased anabolic pathways, has important roles in tumorigenesis, metastasis, drug resistance, and cancer stem cells. Well-known oncogenic signaling pathways, such as phosphoinositide 3-kinase (PI3K)/AKT, Myc, and Hippo pathway, mediate metabolic gene expression and increase metabolic enzyme activities. Vice versa, deregulated metabolic pathways contribute to defects in cellular signal transduction pathways, which in turn provide energy, building blocks, and redox potentials for unrestrained cancer cell proliferation. Studies and clinical trials are being performed that focus on the inhibition of metabolic enzymes by small molecules or dietary interventions (e.g., fasting, calorie restriction, and intermittent fasting). Similar to genetic heterogeneity, the metabolic phenotypes of cancers are highly heterogeneous. This heterogeneity results from diverse cues in the tumor microenvironment and genetic mutations. Hence, overcoming metabolic plasticity is an important goal of modern cancer therapeutics. This review highlights recent findings on the metabolic phenotypes of cancer and elucidates the interactions between signal transduction pathways and metabolic pathways. We also provide novel rationales for designing the next-generation cancer metabolism drugs. Full article

GUN1 (genomes uncoupled 1), a chloroplast-localized pentatricopeptide repeat (PPR) protein with a C-terminal small mutS-related (SMR) domain, plays a central role in the retrograde communication of chloroplasts with the nucleus. This flow of information is required for the coordinated expression of plastid and nuclear genes, and it is essential for the correct development and functioning of chloroplasts. Multiple genetic and biochemical findings indicate that GUN1 is important for protein homeostasis in the chloroplast; however, a clear and unified view of GUN1′s role in the chloroplast is still missing. Recently, GUN1 has been reported to modulate the activity of the nucleus-encoded plastid RNA polymerase (NEP) and modulate editing of plastid RNAs upon activation of retrograde communication, revealing a major role of GUN1 in plastid RNA metabolism. In this opinion article, we discuss the recently identified links between plastid RNA metabolism and retrograde signaling by providing a new and extended concept of GUN1 activity, which integrates the multitude of functional genetic interactions reported over the last decade with its primary role in plastid transcription and transcript editing. Full article