Sphingosylphosphorylcholine stimulates expression of fibronectin through TGF-beta1-Smad-dependent mechanism in human mesenchymal stem cells

ERK2-mediated phosphorylation of ZEB1 at S322 enhances PD-L1 expression and EMT, leading to pancreatic cancer progression

BACKGROUND

Pancreatic cancer is the fourth leading cause of cancer-related deaths. Epithelial-mesenchymal transition (EMT) drives aggressive behaviour and unfavourable outcomes in this disease. The zinc finger E-box-binding homeobox 1 (ZEB1) transcription factor is pivotal in orchestrating EMT, promoting tumor cell mobility, metastasis, and immune evasion through phosphorylation events. However, the precise mechanisms underlying individual phosphorylation sites and their relationship with ZEB1's functions in vivo remain inadequately understood.

METHODS

We assessed EMT using various techniques, including reverse transcription-quantitative polymerase chain reaction (RT-qPCR), immunoblotting, microscopy, migration, and invasion assays. ZEB1 knockdown was achieved via short hairpin RNA (shRNA), while plasmid transfection facilitated the overexpression of ZEB1, extracellular signal-regulated kinase 1 (ERK1), and extracellular signal-regulated kinase 2 (ERK2). Co-immunoprecipitation and kinase assays were used to examine the interaction between ZEB1 and ERK1/2. PANC-1 and HPAC cells were transplanted in an orthotopic mouse model for in vivo analysis.

RESULTS

Sphingosylphosphorylcholine (SPC) induced EMT in PANC-1 and HPAC cells in a dose- and time-dependent manner through the phosphorylation and nuclear translocation of ZEB1. Notably, ERK2 interacted with ZEB1 and catalysed the phosphorylation of serine 322 (S322) within the ZEB1 molecule. Disrupting S322 phosphorylation hindered ZEB1's nuclear translocation, leading to reduced programmed death-ligand 1 (PD-L1) expression and suppressed migration and invasion of pancreatic cancer cells. Furthermore, in an orthotopic mouse model, implantation of S322 phosphorylation-deficient (shZEB1/S322A) pancreatic cancer cells suppressed tumour formation and metastasis. We developed a phosphoS322 detection antibody, which validated ZEB1 phosphorylation in pancreatic cancer cells and tissue samples from patients with pancreatic cancer.

CONCLUSION

SPC induces ZEB1 phosphorylation, with ERK2, rather than ERK1, targeting the S322 site. Inhibiting S322 phosphorylation mitigates EMT, PD-L1 expression, and progression of pancreatic cancer. The phosphoS322 detection antibody might be a valuable tool for predicting pancreatic cancer prognosis. These findings implicate ERK2 as a potential therapeutic target for pancreatic cancer and highlight phosphoZEB1 as a valuable prognostic marker.

Cool Fat, Hot Topic: A Systematic Review on Cryopreservation of Adipose Tissue

Autologous fat grafting is increasingly used in plastic, reconstructive, and esthetic surgery. Cryopreservation offers a promising solution for the long-term storage of adipose tissue, enabling multiple grafting sessions while minimizing patient discomfort associated with repeated liposuction for fat harvesting. This systematic review aims to analyze the current literature focusing on factors that influence the outcome of cryopreservation, including the use of cryoprotectants, the cooling and warming rate, the storage temperature, and the enrichment of cryopreserved fat grafts. A systematic search of the PubMed/MEDLINE database up to November 2024 was performed, including original preclinical and clinical studies written in English describing the cryopreservation of unprocessed or mechanically processed adipose tissue (macrofat, microfat, or nanofat). Eligible articles needed to describe the applied cryopreservation protocol, at least the storage temperature. Studies on cryopreservation of adipose-derived stem cells (ASCs), stromal vascular fraction, microvascular fragments, and other isolated components of adipose tissue were excluded. Data on cryoprotectants, cooling and warming rates, storage temperature, and eventual supplementation or enrichment of frozen fat were collected. Of the 679 records identified, 59 met the inclusion criteria. Adipose tissue cryopreservation at -80°C with a cryoprotectant, controlled slow cooling, and fast warming represented the most often applied protocol with encouraging outcomes in maintaining tissue survival and histological structure. Several studies indicated that the supplementation of frozen adipose tissue with ASCs improves tissue survival. Taken together, existing studies present diverse, and to some extent, conflicting results regarding cryopreservation protocols and their effects on adipose tissue viability. Hence, the ideal cryopreservation protocol for autologous fat remains to be established. Moreover, tailored protocols may be necessary for the cryopreservation of fat derivatives, such as nanofat.

Epidermal growth factor and tumor necrosis factor α cooperatively promote the motility of hepatocellular carcinoma cell lines via synergistic induction of fibronectin by NF-κB/p65

BACKGROUND

The interaction between hepatocellular carcinoma (HCC) cells and their microenvironment plays a fundamental role in tumor metastasis. The HCC microenvironment is rich in epidermal growth factor (EGF) and tumor necrosis factor α (TNFα), which may cooperatively, rather than individually, interact with tumor cells to influence their biological behavior.

METHODS

Immunohistochemistry was performed to study the expression of EGF and TNFα in HCCs. Western blotting, immunofluorescence, qRT-PCR, wound healing scratch and invasion assay, and chromatin immunoprecipitation assays were used to study the combined roles of EGF and TNFα in the motility of HCC cells in vitro.

RESULTS

We demonstrated that both EGF and TNFα were highly expressed in HCCs, and HCCs with higher expression of both EGF and TNFα were more frequently rated as high-grade tumors. In vitro, EGF and TNFα cooperatively promoted the motility of HCC cells mainly via synergistic induction of an extracellular matrix glycoprotein fibronectin (FN). Mechanistically, EGF and TNFα jointly increased the nuclear translocation and PKC mediated phosphorylation of NF-κB/p65 which could bind to the -356bp to -259bp fragment of the FN promoter, leading to a markedly increased activity of the FN promoter in HCC cells.

CONCLUSIONS

HCCs with higher expression of both EGF and TNFα were more frequently rated as high-grade tumors. EGF and TNFα cooperatively promoted the motility of HCC cells mainly through NF-κB/p65 mediated synergistic induction of FN in vitro.

GENERAL SIGNIFICANCE

These findings highlight the crosstalk between EGF and TNFα in promoting HCC, and provide potential targets for HCC prevention and treatment.

Effects of sphingosylphosphorylcholine on cryopreserved fat tissue graft survival

Autogenous microfat grafting is widely used to augment depressed deformities or for other cosmetic purposes. Since the microfat survival rate is unpredictable due to absorption and calcification, previously cryopreserved fat is widely used for secondary procedures. Sphingosylphosphorylcholine (SPC) is a lysophospholipid, which has a role in several cellular responses, and is known to stimulate DNA synthesis and proliferation. Since endothelial progenitor cells (EPCs) are known to enhance the survival rate of transplanted fat tissue, the present study assessed the effects of SPC on EPCs, in order to verify its positive effects on proliferation. Cryopreserved human fat tissues mixed with various concentrations of SPC were grafted into the nude mouse model. After grafting, the viability of each SPC mixed group was determined and compared with that of the non‑SPC group. SPC exhibited a positive effect on EPC proliferation and angiogenic potential over 3 days when used at specific concentrations. The fat grafts of the 3 µM SPC‑treated group weighed significantly more and the volume was markedly increased, as compared with the control group. A reverse transcription‑quantitative polymerase chain reaction was conducted on the total RNA extracted from SPC‑treated fat tissues, which detected increased mRNA expression levels of matrix metallopeptidase‑9 and tumor necrosis factor‑α compared with in the control group. These results indicate that specific concentrations of SPC may exert favorable effects on grafted cryopreserved human fat tissue, which may be due to the increased mRNA expression levels of genes associated with angiogenesis.

Mesenchymal stromal cells for sphincter regeneration

Stress urinary incontinence (SUI), defined as the involuntary loss of considerable amounts of urine during increased abdominal pressure (exertion, effort, sneezing, coughing, etc.), is a severe problem to the individuals affected and a significant medical, social and economic challenge. SUI is associated with pelvic floor debility, absence of detrusor contraction, or a loss of control over the sphincter muscle apparatus. The pathology includes an increasing loss of muscle cells, replacement of muscular tissue with fibrous tissue, and general aging associated processes of the sphincter complex. When current therapies fail to cure or improve SUI, application of regeneration-competent cells may be an alternative therapeutic option. Here we discuss different aspects of the biology of mesenchymal stromal cells, which are relevant to their clinical applications and for regenerating the sphincter complex. However, there are reports in favor of and against cell-based therapies. We therefore summarize the potential and the risks of cell-based therapies for the treatment of SUI.

Exposure to biomass smoke extract enhances fibronectin release from fibroblasts

COPD induced following biomass smoke exposure has been reported to be associated with a more fibrotic phenotype than cigarette smoke induced COPD. This study aimed to investigate if biomass smoke induced extracellular matrix (ECM) protein production from primary human lung fibroblasts in vitro. Primary human lung fibroblasts (n = 5–10) were stimulated in vitro for up to 72 hours with increasing concentrations of biomass smoke extract (BME) or cigarette smoke extract (CSE) prior to being assessed for deposition of ECM proteins, cytokine release, and activation of intracellular signalling molecules. Deposition of the ECM proteins perlecan and fibronectin was upregulated by both CSE (p<0.05) and BME (p<0.05). The release of the neutrophilic chemokine IL-8 was also enhanced by BME. ERK1/2 phosphorylation was significantly upregulated by BME (p<0.05). Chemical inhibition of ERK signalling molecules partially attenuated these effects (p<0.05). Stimulation with endotoxin had no effect. This study demonstrated that BME had similar effects to CSE in vitro and had the capacity to directly induce fibrosis by upregulating production of ECM proteins. The mechanisms by which both biomass and cigarette smoke exposure cause lung damage may be similar.

Functional expression of smooth muscle-specific ion channels in TGF-β(1)-treated human adipose-derived mesenchymal stem cells

Human adipose tissue-derived mesenchymal stem cells (hASCs) have the power to differentiate into various cell types including chondrocytes, osteocytes, adipocytes, neurons, cardiomyocytes, and smooth muscle cells. We characterized the functional expression of ion channels after transforming growth factor-β1 (TGF-β1)-induced differentiation of hASCs, providing insights into the differentiation of vascular smooth muscle cells. The treatment of hASCs with TGF-β1 dramatically increased the contraction of a collagen-gel lattice and the expression levels of specific genes for smooth muscle including α-smooth muscle actin, calponin, smooth mucle-myosin heavy chain, smoothelin-B, myocardin, and h-caldesmon. We observed Ca(2+), big-conductance Ca(2+)-activated K(+) (BKCa), and voltage-dependent K(+) (Kv) currents in TGF-β1-induced, differentiated hASCs and not in undifferentiated hASCs. The currents share the characteristics of vascular smooth muscle cells (SMCs). RT-PCR and Western blotting revealed that the L-type (Cav1.2) and T-type (Cav3.1, 3.2, and 3.3), known to be expressed in vascular SMCs, dramatically increased along with the Cavβ1 and Cavβ3 subtypes in TGF-β1-induced, differentiated hASCs. Although the expression-level changes of the β-subtype BKCa channels varied, the major α-subtype BKCa channel (KCa1.1) clearly increased in the TGF-β1-induced, differentiated hASCs. Most of the Kv subtypes, also known to be expressed in vascular SMCs, dramatically increased in the TGF-β1-induced, differentiated hASCs. Our results suggest that TGF-β1 induces the increased expression of vascular SMC-like ion channels and the differentiation of hASCs into contractile vascular SMCs.

The impact of bioactive lipids on cardiovascular development

Lysophospholipids comprise a group of bioactive molecules with multiple biological functions. The cardinal members of this signalling molecule group are sphingosylphosphorylcholine (SPC), lysophosphatidic acid (LPA), and sphingosine 1-phosphate (S1P) which are, at least in part, homologous to each other. Bioactive lipids usually act via G-protein coupled receptors (GPCRs), but can also function as direct intracellular messengers. Recently, it became evident that bioactive lipids play a role during cellular differentiation development. SPC induces mesodermal differentiation of mouse ES cells and differentiation of promyelocytic leukemia cells, by a mechanism being critically dependent on MEK-ERK signalling. LPA stimulates the clonal expansion of neurospheres from neural stem/progenitor cells and induces c-fos via activation of mitogen- and stress-activated protein kinase 1 (MSK1) in ES cells. S1P acts on hematopoietic progenitor cells as a chemotactic factor and has also been found to be critical for cardiac and skeletal muscle regeneration. Furthermore, S1P promotes cardiogenesis and similarly activates Erk signalling in mouse ES cells. Interestingly, S1P may also act to maintain human stem cell pluripotency. Both LPA and S1P positively regulate the proliferative capacity of murine ES cells. In this paper we will focus on the differential and developmental impact of lysophospholipids on cardiovascular development.

TGF-beta receptor kinase inhibitor LY2109761 reverses the anti-apoptotic effects of TGF-beta1 in myelo-monocytic leukaemic cells co-cultured with stromal cells

Transforming growth factor beta1 (TGF-beta1) is an essential regulator of cell proliferation, survival and apoptosis, depending on the cellular context. TGF-beta1 is also known to affect cell-to-cell interactions between tumour cells and stromal cells. We investigated the role of TGF-beta1 in the survival of myelo-monocytic leukaemia cell lines co-cultured with bone marrow (BM)-derived mesenchymal stem cells (MSC). Treatment with recombinant human (rh)TGF-beta1 inhibited spontaneous and cytarabine-induced apoptosis in U937 cells, most prominently in U937 cells directly attached to MSCs. Conversely, the pro-survival effects of TGF-beta1 were inhibited by LY2109761 or TGF-beta1 neutralizing antibody. rhTGF-beta1 increased pro-survival phosphorylation of Akt, which was inhibited by LY2109761. The combination of rhTGF-beta1 and MSC co-culture induced significant upregulation of C/EBPbeta gene (CEBPB) and protein expression along with increased C/EBPbeta liver-enriched activating protein: liver-enriched inhibitory protein ratio, suggesting the novel role of C/EBPbeta in TGF-beta1-mediated U937 cell survival in the context of stromal cell support. In summary, these results indicate that TGF-beta1 produced by BM stromal cells promotes the survival and chemoresistance of leukaemia cells under the direct cell-to-cell interactions. The blockade of TGF-beta signalling by LY2109761, which effectively inhibited the pro-survival signalling, may enhance the efficacy of chemotherapy against myelo-monocytic leukaemic cells in the BM microenvironment.