LAMP2 Expression Research Articles

RIPK2 and lysosomal pathway: Unveiling a new mechanism for lung cancer metastasis

BackgroundThis study aims to explore the role of RIPK2 in lung cancer metastasis and its potential mechanisms. MethodsThe expression levels of RIPK2 in lung cancer patients and cell lines were detected by immunohistochemistry, qRT-PCR, and Western blot. RIPK2 expression was knocked down using siRNA technology, and its effects on the proliferation, migration, and invasion capabilities of lung cancer cells were assessed through CCK-8, EdU, colony formation, and Transwell assays. Furthermore, by overexpressing RIPK2 and LAMP2, the regulatory effect of RIPK2 on the lysosomal pathway and its mechanism of action in lung cancer metastasis were investigated. ResultsThe results showed that the expression of RIPK2 was significantly increased in lung cancer patients and cell lines. Knockdown of RIPK2 significantly inhibited the migration, invasion, and proliferation capabilities of lung cancer cells, while overexpression of RIPK2 promoted these malignant behaviors. Further studies found that RIPK2 promoted lung cancer metastasis by inhibiting LAMP2 expression, thereby suppressing the lysosomal pathway and altering the tumor microenvironment. Additionally, overexpression of LAMP2 could reverse the promotive effects of RIPK2 overexpression on the malignant behaviors of lung cancer cells. ConclusionThis study reveals for the first time that RIPK2 promotes lung cancer metastasis by inhibiting LAMP2 expression, thereby suppressing the lysosomal pathway and altering the tumor microenvironment. In the future, targeted therapy against RIPK2 and LAMP2 may become an effective means to inhibit lung cancer metastasis.

Lysosomal LRRC8 complex regulates lysosomal pH, morphology and systemic glucose metabolism.

The lysosome integrates anabolic signalling and nutrient-sensing to regulate intracellular growth pathways. The leucine-rich repeat containing 8 (LRRC8) channel complex forms a lysosomal anion channel and regulates PI3K-AKT-mTOR signalling, skeletal muscle differentiation, growth, and systemic glucose metabolism. Here, we define the endogenous LRRC8 subunits localized to a subset of lysosomes in differentiated myotubes. We show LRRC8A regulates leucine-stimulated mTOR, lysosome size, number, pH, and expression of lysosomal proteins LAMP2, P62, LC3B, suggesting impaired autophagic flux. Mutating a LRRC8A lysosomal targeting dileucine motif sequence (LRRC8A-L706A;L707A) in myotubes recapitulates the abnormal AKT signalling and altered lysosomal morphology and pH observed in LRRC8A KO cells. In vivo , LRRC8A-L706A;L707A KI mice exhibit increased adiposity, impaired glucose tolerance and insulin resistance characterized by reduced skeletal muscle glucose-uptake, and impaired incorporation of glucose into glycogen. These data reveal a lysosomal LRRC8 mediated metabolic signalling function that regulates lysosomal activity, systemic glucose homeostasis and insulin-sensitivity.

Enhanced phagocytosis associated with multinucleated microglia via Pyk2 inhibition in an acute β-amyloid infusion model

Multinucleated microglia have been observed in contexts associated with infection, inflammation, and aging. Though commonly linked to pathological conditions, the larger cell size of multinucleated microglia might enhance their phagocytic functions, potentially aiding in the clearance of brain debris and suggesting a reassessment of their pathological significance. To assess the phagocytic capacity of multinucleated microglia and its implications for brain debris clearance, we induced their formation by inhibiting Pyk2 activity using the pharmacological inhibitor PF-431396, which triggers cytokinesis regression. Multinucleated microglia demonstrate enhanced phagocytic function, as evidenced by their increased capacity to engulf β-amyloid (Aβ) oligomers. Concurrently, the phosphorylation of Pyk2, induced by Aβ peptide, was diminished upon treatment with a Pyk2 inhibitor (Pyk2-Inh, PF-431396). Furthermore, the increased expression of Lamp1, a lysosomal marker, with Pyk2-inh treatment, suggests an enhancement in proteolytic activity. In vivo, we generated an acute Alzheimer’s disease (AD) model by infusing Aβ into the brains of Iba-1 EGFP transgenic (Tg) mice. The administration of the Pyk2-Inh led to an increased migration of microglia toward amyloid deposits in the brains of Iba-1 EGFP Tg mice, accompanied by morphological activation, suggesting a heightened affinity for Aβ. In human microglia, lipopolysaccharide (LPS)-induced inflammatory responses showed that inhibition of Pyk2 signaling significantly reduced the transcription and protein expression of pro-inflammatory markers. These results suggest that Pyk2 inhibition can modulate microglial functions, potentially reducing neuroinflammation and aiding in the clearance of neurodegenerative disease markers. This highlights Pyk2 as a promising target for therapeutic intervention in neurodegenerative diseases.

BACE1 inhibitors from the fruits of Alpinia oxyphylla have efficacy to treat T2DM-related cognitive disorder

The fruits of Alpinia oxyphylla (Alpiniae Oxyphyllae Fructus, AOF) are one of the “Four Famous South Medicines” in China. In this study, beta-site amyloid protein precursor cleaving enzyme 1 (BACE1) was applied to explore the active components in AOF responsible for type 2 diabetes mellitus (T2DM)-related cognitive disorder. As a result, 24 compounds including three unreported ones (1, 3, 4) were isolated from AOF. Compound 1 is an unusual carbon‑carbon linked diarylheptanoid dimer, and compound 4 is the first case of 3,4-seco-eudesmane sesquiterpenoid with a 5/6-bicyclic skeleton. Four diarylheptanoids (3, 5–7), one flavonoid (9) and two sesquiterpenoids (14 and 20) showed BACE1 inhibitory activity, of which the most active 6 was revealed to be a non-competitive and anti-competitive mixed inhibitor. Docking simulation suggested that OH-4′ of 6 played important roles in maintaining activity by forming hydrogen bonds with Ser36 and Ile126 residues. Compounds 3, 5, 9 and 20 displayed neuroprotective effects against amyloid β (Aβ)-induced damage in BV2 cells. Mechanism study revealed that compounds 5 and 20 downregulated the expression of BACE1 and upregulated the expression of Lamp2 to exert effects. Thus, the characteristic diarylheptanoids and sesquiterpenoids in AOF had the efficacy to alleviate T2DM-related cognitive disorder by inhibiting BACE1 activity and reversing Aβ-induced neuronal damage.

Abstract Or125: Numb Family Proteins regulate left ventricular compaction by modulating autophagic process

Background: Left ventricular noncompaction (LVNC) is a type of cardiomyopathy, which patients manifest clinical features of heart failure, arrhythmias, thrombotic events, and sudden death. We previously found that the ablation of Numb(Nb) , and its homologue Numbl(Nl) at early stage, causes LVNC defects resulting in embryonic lethality. In this study, we found that mice with Nb and Nl deletion at later stage survive to adulthood and develop toLVNC cardiomyopathy. Method: We applied aMHC-Cre to delete and generate Nb and Nl double knockout (ADKO); examine the structure and functions of the ADKO hearts via echocardiography (ECHO); determine the heart arrhythmia via telemetry; determine the Nb subcellular localization via a Nb overexpression line (R26-Flag:mCherry:Numb); and determine the mechanistic function of NFPs in autophagy via autophagic reporter, electron microscopy, and molecular and biochemical assays. Results: The cTnT-Cre mediated Nb and Nl deletion causes LVNC and embryonic lethality, while the ADKO can survive to adulthood and died between eight- and twelve-month-old. The ADKO hearts display LVNC by two months of age, a reduced systolic function by four months old, and left ventricular remodeling and dilatation starting at six months old. ADKO hearts manifest major clinical features of LVNC, including arrhythmias and thrombosis. ADKO hearts exhibit significant accumulation of damaged mitochondria, autophagosomes and autophagolysosomes compared to controls. Biochemical analyses reveal elevated levels of p62 and a higher ratio of LC3II/LC3I in ADKO hearts. NFP null cells and ADKO hearts exhibit abnormal autophagic flux, characterized by arrested at autophagolysosome, increased expression of Lamp1 and Lamp2, but reduced levels of cathepsin D. Mass spectrometry analyses reveal Numb's interaction with proteins involved in endocytosis and autophagy. Consistently, Numb localizes to autophagosomes and autophagolysosomes. Conclusion: NFPs regulate left ventricular compaction at both embryonic and postnatal stages, suggesting that LVNC can be both congenital and acquired. As LVNC mice progress, they develop dilated cardiomyopathy (DCM) at later stage, suggesting that LVNC can occur independently at early stage, and is associated with DCM at later stage. Deletion of NFPs in cardiomyocytes disrupts endocytosis and autophagic flux. Our studies suggest that NFPs mediated endocytosis and autophagy are essential for left ventricular compaction.

E3 Ubiquitin Ligase RNF13 Suppresses TLR Lysosomal Degradation by Promoting LAMP-1 Proteasomal Degradation.

As a highly organized system, endo-lysosomes play a crucial role in maintaining immune homeostasis. However, the mechanisms involved in regulating endo-lysosome progression and subsequent inflammatory responses are not fully understood. By screening 103 E3 ubiquitin ligases in regulating endo-lysosomal acidification, it is discovered that lysosomal RNF13 inhibits lysosome maturation and promotes inflammatory responses mediated by endosomal Toll-like receptors (TLRs) in macrophages. Mechanistically, RNF13 mediates K48-linked polyubiquitination of LAMP-1 at residue K128 for proteasomal degradation. Upon TLRs activation, LAMP-1 promotes lysosomes maturation, which accelerates lysosomal degradation of TLRs and reduces TLR signaling in macrophages. Furthermore, peripheral blood mononuclear cells (PBMCs) from patients with rheumatoid arthritis (RA) show increased RNF13 levels and decreased LAMP-1 expression. Accordingly, the immunosuppressive agent hydroxychloroquine (HCQ) can increase the polyubiquitination of RNF13. Taken together, the study establishes a linkage between proteasomal and lysosomal degradation mechanisms for the induction of appropriate innate immune response, and offers a promising approach for the treatment of inflammatory diseases by targeting intracellular TLRs.

The cGAS-STING pathway drives inflammation in Usual Interstitial Pneumonia, phagocytosis could prevent inflammation but is inhibited by the don’t eat me signal CD47

BackgroundUsual Interstitial Pneumonia (UIP) a fibrosing pneumonia is associated with idiopathic pulmonary fibrosis, chronic autoimmune disease (AID), or hypersensitivity pneumonia. Oxygen radicals, due to tobacco smoke, can damage DNA and might upregulate PARP1. Cytosolic DNA from dying pneumocytes activate cytosolic GMP-AMP-synthase–stimulator of interferon genes (cGAS-STING) pathway and TREX1. Prolonged inflammation induces senescence, which might be inhibited by phagocytosis, eliminating nuclear debris. We aimed to evaluate activation of cGAS-STING-TREX1 pathway in UIP, and if phagocytosis and anti-phagocytosis might counteract inflammation. Methods44 cases of UIP with IPF or AID were studied for the expression of cGAS, pSTING, TREX1 and PARP1. LAMP1 and Rab7 expression served as phagocytosis markers. CD47 protecting phagocytosis and p16 to identify senescent cells were also studied. ResultsEpithelial cells in remodeled areas and macrophages expressed cGAS-pSTING, TREX1; epithelia but not macrophages stained for PARP1. Myofibroblasts, endothelia, and bronchial/bronchiolar epithelial cells were all negative except early myofibroblastic foci expressing cGAS. Type II pneumocytes expressed cGAS and PARP1, but less pSTING. TREX1 although expressed was not activated. Macrophages and many regenerating epithelial cells expressed LAMP1 and Rab7. CD47, the ’don’t-eat-me-signal‘, was expressed by macrophages and epithelial cells including senescence cells within the remodeled areas. ConclusionsThe cGAS-STING pathway is activated in macrophages and epithelial cells within remodeled areas. LikelyTREX1 because not activated cannot sufficiently degrade DNA fragments. PARP1 activation points to smoking-induced oxygen radical release, prolonging inflammation and leading to fibrosis. By expressing CD47 epithelial cells within remodeled areas protect themselves from being eliminated by phagocytosis.

JEV infection leads to dysfunction of lysosome by downregulating the expression of LAMP1 and LAMP2

Japanese Encephalitis Virus (JEV), the predominant cause of viral encephalitis in many Asian countries, affects approximately 68,000 people annually. Lysosomes are dynamic structures that regulate cellular metabolism by mediating lysosomal biogenesis and autophagy. Here, we showed that lysosome-associated membrane protein 1 (LAMP1) and LAMP2 were downregulated in cells after JEV infection, resulting in a decrease in the quantity of acidified lysosomes and impaired lysosomal catabolism. What’s more, JEV nonstructural protein 4B plays key roles in the reduction of LAMP1/2 via the autophagy-lysosome pathway. JEV NS4B also promoted abnormal aggregation of SLA-DR, an important component of the swine MHC-II molecule family involved in antigen presentation and CD4+ cell activation initiation. Mechanistically, NS4B localized to the ER during JEV infection and interacted with GRP78, leading to the activation of ER stress-mediated autophagy. The 131–204 amino acid (aa) region of NS4B is essential for autophagy induction and LAMP1/2 reduction. In summary, our findings reveal a novel pathway by which JEV induces autophagy and disrupts lysosomal function.

Lysosomal dysfunction and overload of nucleosides in thymidine phosphorylase deficiency of MNGIE

Inherited deficiency of thymidine phosphorylase (TP), encoded by TYMP, leads to a rare disease with multiple mitochondrial DNA (mtDNA) abnormalities, mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). However, the impact of TP deficiency on lysosomes remains unclear, which are important for mitochondrial quality control and nucleic acid metabolism. Muscle biopsy tissue and skin fibroblasts from MNGIE patients, patients with m.3243 A > G mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and healthy controls (HC) were collected to perform mitochondrial and lysosomal functional analyses. In addition to mtDNA abnormalities, compared to controls distinctively reduced expression of LAMP1 and increased mitochondrial content were detected in the muscle tissue of MNGIE patients. Skin fibroblasts from MNGIE patients showed decreased expression of LAMP2, lowered lysosomal acidity, reduced enzyme activity and impaired protein degradation ability. TYMP knockout or TP inhibition in cells can also induce the similar lysosomal dysfunction. Using lysosome immunoprecipitation (Lyso- IP), increased mitochondrial proteins, decreased vesicular proteins and V-ATPase enzymes, and accumulation of various nucleosides were detected in lysosomes with TP deficiency. Treatment of cells with high concentrations of dThd and dUrd also triggers lysosomal dysfunction and disruption of mitochondrial homeostasis. Therefore, the results provided evidence that TP deficiency leads to nucleoside accumulation in lysosomes and lysosomal dysfunction, revealing the widespread disruption of organelles underlying MNGIE.Graphical

Increased interleukin-6 correlates with LAMP1 expression in NK cells and hospital stay of patients with SARS-COV-2 pneumonia.

Abstract During viral infections, NK cells play an important role in virus clearance. In the course of COVID-19 pandemic, the immunologic response to viral infections gains a main interest. Despite the extensive evidence, the functional status of cytotoxic cells has remained a controversial area of interest. Here, we provide a detailed comparative analysis of immune population counts and activation markers expression (LAMP1, IFNγ, KIR2DL1 and granzyme B) in NK cells from blood by flow cytometry, and serum cytokine concentration by LUMINEX from patients with severe COVID-19 and healthy participants. A significant decrease in total lymphocyte was observed in COVID-19 patients, mainly by T-CD4+, T-CD8+ and NK cells. The expression of the activation marker LAMP1 on NK cells was significantly higher in COVID-19 patients compared with the control group (P<0.05), and its expression was related to their clinical outcome. Also, IL-6 concentration was significantly higher in COVID-19 patients, correlated negatively with LAMP1 expression (r2=-0.693, P<0.05) and positively with hospital stay (r2=0.752, P<0.01). In conclusion, we show evidence of increased expression of the activation marker LAMP1 in NK cells, and high levels of IL-6 in COVID-19 patients, as well as, their correlation with the clinical outcome and hospital stay of the patients.

CX-4945 (Silmitasertib) Induces Cell Death by Impairing Lysosomal Utilization in KRAS Mutant Cholangiocarcinoma Cell Lines.

Macropinocytosis is a non-selective form of endocytosis that facilitates the uptake of extracellular substances, such as nutrients and macromolecules, into the cells. In KRAS-driven cancers, including pancreatic ductal adenocarcinoma, macropinocytosis and subsequent lysosomal utilization are known to be enhanced to overcome metabolic stress. In this study, we investigated the role of Casein Kinase 2 (CK2) inhibition in macropinocytosis and subsequent metabolic processes in KRAS mutant cholangiocarcinoma (CCA) cell lines. The bovine serum albumin (BSA) uptake indicating macropinocytosis was performed by flow cytometry using the HuCCT1 KRAS mutant CCA cell line. To validate macropinosome, the Rab7 and LAMP2 were labeled and analyzed via immunocytochemistry and western blot. The CX-4945 (Silmitasertib), CK2 inhibitor, was used to investigate the role of CK2 in macropinocytosis and subsequent lysosomal metabolism. The TFK-1, a KRAS wild-type CCA cell line, showed only apoptotic morphological changes. However, the HuCCT1 cell line showed macropinocytosis. Although CX-4945 induced morphological changes accompanied by the accumulation of intracellular vacuoles and cell death, the level of macropinocytosis did not change. These intracellular vacuoles were identified as late macropinosomes, representing Rab7+ vesicles before fusion with lysosomes. In addition, CX-4945 suppressed LAMP2 expression following the inhibition of the Akt-mTOR signaling pathway, which interrupts mature macropinosome and lysosomal metabolic utilization. Macropinocytosis is used as an energy source in the KRAS mutant CCA cell line HuCCT1. The inhibition of CK2 by CX-4945 leads to cell death in HuCCT1 cells through alteration of the lysosome-dependent metabolism.

Infection of Human Macrophage-Like Cells by African Swine Fever Virus.

The African swine fever (ASF) virus (ASFV) and ASF-like viral sequences were identified in human samples and sewage as well as in different water environments. Pigs regularly experience infections by the ASFV. The considerable stability of the virus in the environment suggests that there is ongoing and long-term contact between humans and the ASFV. However, humans exhibit resistance to the ASFV, and the decisive factor in developing infection in the body is most likely the reaction of target macrophages to the virus. Therefore, this study aimed to characterize the responses of human macrophages to the virus and explore the distinct features of the viral replication cycle within human macrophages. The ASFV Armenia/07 strain was used in all experiments. In this study, quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the ASFV gene expression; flow cytometry analysis was performed to evaluate the effects of the inactive and active ASFV (inASFV and aASFV) treatments on the phenotype of THP-1-derived macrophages (Mφ0) and inflammatory markers. Moreover, other methods such as cell viability and apoptosis assays, staining techniques, phagocytosis assay, lysosome-associated membrane protein (LAMP-1) cytometry, and cytokine detection were used during experiments. Our findings showed that the virus initiated replication by entering human macrophages. Subsequently, the virus shed its capsid and initiated the transcription of numerous viral genes, and at least some of these genes executed their functions. In THP-1-derived macrophages (Mφ0), the ASFV implemented several functions to suppress cell activity, although the timing of their implementation was slower compared with virus-sensitive porcine alveolar macrophages (PAMs). Additionally, the virus could not complete the entire replication cycle in human Mφ0, as indicated by the absence of viral factories and a decrease in infectious titers of the virus with each subsequent passage. Overall, the infection of Mφ0 with the ASFV caused significant alterations in their phenotype and functions, such as increased TLR2, TLR3, CD80, CD36, CD163, CXCR2, and surface LAMP-1 expression. Increased production of the tumor necrosis factor (TNF) and interleukin (IL)-10 and decreased production of interferon (IFN)-α were also observed. Taken together, the virus enters human THP-1-derived macrophages, starts transcription, and causes immunological responses by target cells but cannot complete the replicative cycle. These findings suggest that there may be molecular limitations within human macrophages that at least partially restrict the complete replication of the ASFV. Understanding the factors that hinder viral replication in Mφ0 can provide valuable insights into the host-virus interactions and the mechanisms underlying the resistance of human macrophages to the ASFV.

High copper levels induce premature senescence in 3T3-L1 preadipocytes

Copper (Cu) dyshomeostasis has been linked to obesity and related morbidities and also to aging. Cu levels are higher in older or obese individuals, and adipose tissue (AT) Cu levels correlate with body mass index. Aging and obesity induce similar AT functional and structural changes, including an accumulation of senescent cells. To study the effect of Cu-mediated stress-induced premature senescent (Cu-SIPS) on preadipocytes, 3T3-L1 cell line was exposed to a subcytotoxic concentration of copper sulfate. After Cu treatment, preadipocytes acquired typical senescence characteristics including diminished cell proliferation, cell and nuclei enlargement and increased lysosomal mass (higher Lamp2 expression and a slight increased number of cells positive for β-galactosidase associated with senescence (SA-β-Gal)). Cell cycle arrest was due to upregulation of p16Ink4aInk4a and p21Waf1/Cip1. Accordingly, protein levels of the proliferation marker KI67 were reduced. Cu-SIPS relates with oxidative stress and, in this context, an increase of SOD1 and HO-1 expression was detected in Cu-treated cells. The mRNA expression of senescence-associated secretory phenotype factors, such as Mmp3, Il-6 and Tnf-α, increased in Cu-SIPS 3T3-L1 cells but no effect was observed on the expression of heterochromatin-associated protein 1(HP1).Although the downregulation of Lamin B1 expression is considered a hallmark of senescence, Cu-SIPS cells presented higher levels of Lamin B1. The dysregulation of nuclear lamina was accompanied by an increase of nuclear blebbing, but not of micronuclei number.To conclude, a Cu-SIPS model in 3T3-L1 preadipocytes is here described, which may be an asset to the study of AT dysregulation observed in obesity and aging.

Rhizoma Alismatis Decoction improved mitochondrial dysfunction to alleviate SASP by enhancing autophagy flux and apoptosis in hyperlipidemia acute pancreatitis

BackgroundAcute pancreatitis (AP) is an inflammatory disorder of the exocrine pancreas, especially hyperlipidemia acute pancreatitis (HLAP) is the third leading cause of acute pancreatitis which is more severe with a greater incidence of persistent multiorgan failure. HLAP inflicts injury upon the organelles within the acinar cell, particularly mitochondria, the endolysosomal–autophagy system, and is accompanied by senescence-associated secretory phenotype (SASP). RAD, only two consists of Rhizoma Alismatis and Atractylodes macrocephala Rhizoma, which is best known for its ability to anti-inflammatory and lipid-lowering. Nevertheless, the mechanism by which RAD alleviates HLAP remains obscure, necessitating further investigation. PurposeThe study aimed to assess the effects of the RAD on HLAP and to elucidate the underlying mechanism in vivo and in vitro, offering a potential medicine for clinical treatment for HLAP. Study design and methodsC57BL/6 mice with hyperlipidemia acute pancreatitis were induced by HFD and CER, then administrated with RAD. AR42J were stimulated by cerulein or conditioned medium and then cultured with RAD. Serums were analyzed to evaluate potential pancreas and liver damage. Furthermore, tissue samples were obtained for histological, and protein investigations by H&E, Oil red staining, and Western blot. In addition, western blot and immunofluorescent staining were utilized to estimate the effect of RAD on mitochondrial function, autophagy flux, and SASP. ResultsIn vivo, RAD considerably alleviated systemic inflammation while attenuating TC, TG, AMY, LPS, inflammatory cytokines, histopathology changes, oxidative damage, mitochondrial fission, and autophagy markers in HLAP mice. Impaired autophagy flux and mitochondrial dysfunction resulted in a significant enhancement of NLRP3 and IL-1β in the pancreas. RAD could reverse these changes. In vitro, RAD significantly restored mitochondrial membrane potential and oxidative phosphorylation levels. RAD decreased Beclin-1 and LC3-II expression and increased LAMP-1 and Parkin-Pink expression, which showed that RAD significantly ameliorated HLAP-induced damage to the mitochondria function by suppressing mitochondrial oxidative damage and enhancing autophagy flux and mitophagy to remove the damaged mitochondria. In addition, we found that RAD could up-regulate the expression of BAX, and Bad and down-regulate the expression of p16, and p21, indicating that RAD could promote damaged cell apoptosis and alleviate SASP. ConclusionsThis study revealed that RAD ameliorates mitochondrial function to alleviate SASP through enhancing autophagy flux, mitophagy, and apoptosis which provided a molecular basis for the advancement and development of protection strategies against HLAP.

Exosomes biogenesis was increased in metformin-treated human ovary cancer cells; possibly to mediate resistance

BackgroundExosomes derived from tumor cells contribute to the pathogenesis of cancers. Metformin, the most usually used drug for type 2 diabetes, has been frequently investigated for anticancer effects. Here, we examined whether metformin affects exosomes signaling in human ovary cancer cells in vitro.MethodsHuman ovary cancer cells, including A2780 and Skov3 cells, were treated with metformin for either 24–48 h. Cell viability and caspase-3 activity were determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) and colorimetric assays respectively. Oil-Red-O staining and in vitro, scratch assays were used to examine cellular toxicity and wound healing rate. After treatment with metformin, exosomes were isolated from cells and quantified by acetylcholinesterase (AChE) assay, Dynamic Light Scattering (DLS), and their markers. Genes related to exosomes signaling were analyzed by real-time PCR or western blotting.ResultsOur results showed that metformin decreased the viability of both cells dose/time-dependently (P < 0.05). Metformin increased the activity of caspase-3 (P < 0.05) as well as the number of Oil-Red-O positive cells in both cell lines. In vitro scratch assay showed that the cell migration rate of metformin-treated cells was decreased (P < 0.05), whereas AChE activity of exosomes from metformin-treated cells was increased (P < 0.05). Concurrent with an increase in CD63 protein levels, expression of Alix, CD63, CD81, Lamp-2, and Rab27b up-regulated in treated cells (P < 0.05).ConclusionResults indicated that metformin had a cytotoxic effect on ovary cancer cells and enhanced exosome biogenesis and secretion.

Characterization of three lamp genes from largemouth bass (Micropterus salmoides): molecular cloning, expression patterns, and their transcriptional levels in response to fast and refeeding strategy.

Lysosomes-associated membrane proteins (LAMPs), a family of glycosylated proteins and major constituents of the lysosomal membranes, play a dominant role in various cellular processes, including phagocytosis, autophagy and immunity in mammals. However, their roles in aquatic species remain poorly known. In the present study, three lamp genes were cloned and characterized from Micropterus salmoides. Subsequently, their transcriptional levels in response to different nutritional status were investigated. The full-length coding sequences of lamp1, lamp2 and lamp3 were 1251bp, 1224bp and 771bp, encoding 416, 407 and 256 amino acids, respectively. Multiple sequence alignment showed that LAMP1-3 were highly conserved among the different fish species, respectively. 3-D structure prediction, genomic survey, and phylogenetic analysis were further confirmed that these genes are widely existed in vertebrates. The mRNA expression of the three genes was ubiquitously expressed in all selected tissues, including liver, brain, gill, heart, muscle, spleen, kidney, stomach, adipose and intestine, lamp1 shows highly transcript levels in brain and muscle, lamp2 displays highly expression level in heart, muscle and spleen, but lamp3 shows highly transcript level in spleen, liver and kidney. To analyze the function of the three genes under starvation stress in largemouth bass, three experimental treatment groups (fasted group and refeeding group, control group) were established in the current study. The results indicated that the expression of lamp1 was significant induced after starvation, and then returned to normal levels after refeeding in the liver. The expression of lamp2 and lamp3 exhibited the same trend in the liver. In addition, in the spleen and the kidney, the transcript level of lamp1 and lamp2 was remarkably increased in the fasted treatment group and slightly decreased in the refed treatment group, respectively. Collectively, our findings suggest that three lamp genes may have differential function in the immune and energetic organism in largemouth bass, which is helpful in understanding roles of lamps in aquatic species.

ALKBH5 suppresses autophagic flux via N6-methyladenosine demethylation of ZKSCAN3 mRNA in acute pancreatitis.

Increasing evidence has demonstrated that N6-methyladenosine (m6A) RNA modification plays an essential role in a wide range of pathological conditions. Impaired autophagy is a critical hallmark of acute pancreatitis (AP). To explore the role of the m6A modification of ZKSCAN3 in the regulation of autophagy in AP. The AP mouse cell model was established by cerulein-treated mouse pancreatic acinar cells (MPC-83), and the results were confirmed by the levels of amylase and inflammatory factors. Autophagy activity was evaluated by specific identification of the autophagy-related microstructure and the expression of autophagy-related genes. ZKSCAN3 and ALKBH5 were knocked down to study the function in AP. A m6A RNA binding protein immunoprecipitation assay was used to study how the m6A modification of ZKSCAN3 mRNA is regulated by ALKBH. The increased expression of amylase and inflammatory factors in the supernatant and the accumulation of autophagic vacuoles verified that the AP mouse cell model was established. The downregulation of LAMP2 and upregulation of LC3-II/I and SQSTM1 demonstrated that autophagy was impaired in AP. The expression of ZKSCAN3 was upregulated in AP. Inhibition of ZKSCAN3 increased the expression of LAMP2 and decreased the expression of the inflammatory factors, LC3-II/I and SQSTM1. Furthermore, ALKBH5 was upregulated in AP. Knockdown of ALKBH5 downregulated ZKSCAN3 expression and restored decreased autophagic flux in AP. Notably, the bioinformatic analysis revealed 23 potential m6A modification sites on ZKSCAN3 mRNA. The m6A modification of ZKSCAN3 mRNA was significantly decreased in AP. Knockdown of ALKBH5 increased the modification of ZKSCAN3 mRNA, which confirmed that ALKBH5 upregulated ZKSCAN3 expression in a m6A-dependent manner. ALKBH5 inhibits autophagic flux through m6A demethylation of ZKSCAN3 mRNA in AP, thereby aggravating the severity of the disease.

Identification and validation of the biomarkers related to ferroptosis in calcium oxalate nephrolithiasis.

Ferroptosis is a specific type of programmed cell death characterized by iron-dependent lipid peroxidation. Understanding the involvement of ferroptosis in calcium oxalate (CaOx) stone formation may reveal potential targets for this condition. The publicly available dataset GSE73680 was used to identify 61 differentially expressed ferroptosis-related genes (DEFERGs) between normal kidney tissues and Randall's plaques (RPs) from patients with nephrolithiasis through employing weighted gene co-expression network analysis (WGCNA). The findings were validated through in vitro and in vivo experiments using CaOx nephrolithiasis rat models induced by 1% ethylene glycol administration and HK-2 cell models treated with 1 mM oxalate. Through WGCNA and the machine learning algorithm, we identified LAMP2 and MDM4 as the hub DEFERGs. Subsequently, nephrolithiasis samples were classified into cluster 1 and cluster 2 based on the expression of the hub DEFERGs. Validation experiments demonstrated decreased expression of LAMP2 and MDM4 in CaOx nephrolithiasis animal models and cells. Treatment with ferrostatin-1 (Fer-1), a ferroptosis inhibitor, partially reversed oxidative stress and lipid peroxidation in CaOx nephrolithiasis models. Moreover, Fer-1 also reversed the expression changes of LAMP2 and MDM4 in CaOx nephrolithiasis models. Our findings suggest that ferroptosis may be involved in the formation of CaOx kidney stones through the regulation of LAMP2 and MDM4.

Abstract 7584: The solute transported xCT (SLC7A11) modulates lysosome biogenesis and microRNA trafficking in drug resistant renal cell carcinoma

Abstract Multi-tyrosine kinase inhibitors (TKIs) like sunitinib bind to over 50 kinases and inhibit several receptors such as VEGFR-1, VEGFR-2, and VEGFR-3 receptors, PDGFRa and PDGFRb, RET, cKIT, and FLT3. TKIs are effective drugs for the treatment of renal cell carcinoma (RCC) but intrinsic/acquired resistance remains a major hurdle. One of the proposed models for TKI resistance is drug sequestration by lysosomes. The solute transporter xCT is a cystine/glutamate antiporter that plays a role in the production of antioxidants in cancer cells. Our lab has found that SLC7A11, the gene that encodes xCT, is overexpressed in sunitinib resistant RCC cells. LAMP1 expression was also increased in sunitinib resistant RCC cells, suggesting an upregulation of lysosome biogenesis. The biochemical knock down of SLC7A11 by shRNA showed a decrease in LAMP1 expression, suggesting a decrease in lysosome biogenesis. SEC24D is a key catalytic component of COPII complex involved in formation of exosomes and secretory pathways. Our preliminary data showed that reduction in xCT expression was associated with a decrease in SEC24D protein levels which was associated with a reduction in the extracellular export and, consequently, an increase in intracytoplasmic levels of miRNA 605, a known tumor suppressor. We are currently testing the hypothesis that xCT may modulate lysosomes biogenesis and micro-RNA trafficking in several clear cell and translation renal cell carcinoma models. In summary, a better understanding of the role of xCT in the regulation of intracytoplasmic organelles may lead to the identification of a novel therapeutic strategy to overcome TKI resistance in RCC. Citation Format: Abbas Jawadwala, Christopher Rupert, Remi Adelaiye-Ogala, Roberto Pili, Sreenivasulu Chintala, Ashley Orillion, May Elbanna, Nur Damayanti, Ilaria Delle Fontane. The solute transported xCT (SLC7A11) modulates lysosome biogenesis and microRNA trafficking in drug resistant renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7584.

Abstract 1326: Pre-clinical development of ARB011: A CDH17 targeting allogeneic nonviral RNA-based “Flash” CAR-NK therapy for gastrointestinal cancer

Abstract Background: Treatment for advanced gastrointestinal (GI) cancers has remained challenging, therefore, novel immunotherapies using chimeric antigen receptor (CAR)-T cells are being developed as a new hope for the patients. However, despite the clinical successes in hematologic malignancies, the overall safety and efficacy against solid tumors of CAR-T cells have yet to be established, and the manufacturing of autologous CAR-T cells requires lengthy cell expansion and viral transduction processes. In view of these technical challenges, we have developed ARB011, an RNA-based allogeneic CAR-NK therapy targeting GI cancers expressing cadherin-17 (CDH17), a promising therapeutic target with its overexpression associated with poor prognosis in patients with GI cancers. The use of allogeneic NK cells would mitigate the risk of graft-versus-host disease. Moreover, engineering NK cells with nonviral CAR-encoding mRNA would provide a rapid large-scale manufacturing platform with minimal risk of abnormal genetic alteration mediated by viral integration. Methods: To generate the ARB011 CAR-NK cells, ex vivo expanded human peripheral blood NK (Magicell-NK, Medigen, Taiwan) cells were electroporated with mRNA encoding a humanized anti-CDH17 scFv fused with transactivation domains. Flow cytometry, in vitro cytotoxicity assay, and cytokine release assay were performed to evaluate the expression and functionality of ARB011. To examine the developability of ARB011 as an off-the-shelf cell product, cryopreservation and large-scale electroporation were also studied. Results: Flow cytometry analysis revealed efficient electroporation with a high level of CDH17 CAR expression (&amp;gt;80%) and optimal CAR-NK cell viability (60%-80%). Following electroporation, cytotoxicity of ARB011 was tested against gastric (AGS and NCI-N87), colorectal (DLD-1 and T84), and liver (MHCC-97H) cancer cells by co-culturing at 1:1 and 2:1 effector/target ratio for 12-24h. ARB011 showed significant cytotoxicity against CDH17+ but not CDH17- cancer cells. The CDH17-sepcific cytotoxicity was accompanied with elevated levels of CD107a or LAMP-1 expression on CAR-NK cells and IFN-γ and TNF-α releases. Interestingly, cryopreserved ARB011 maintained optimal cell viability, CAR expression, and potent CDH17 target-specific cytolytic activity. Lastly, large-scale electroporation showed the establishment of up-scaling process of ARB011 production for clinical application. Conclusions: Overall, the findings suggest that ARB011 could be a novel off-the-shelf, CAR-NK therapy that warrants further studies in animal models and in clinical trials. Citation Format: Jaydeep Roy, Nga Tin Lin, Kronos Chow, Chih Ya Yang, James C.L. Lin, John M. Luk, Kwong F. Wong. Pre-clinical development of ARB011: A CDH17 targeting allogeneic nonviral RNA-based “Flash” CAR-NK therapy for gastrointestinal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1326.