Leukemia Inhibitory Factor Protein Research Articles

Abstract B095: Leukemia inhibitory factor fosters tumor growth in KRAS-driven pancreatic ductal adenocarcinoma

Abstract While inflammation is a known and well-validated risk factor for developing pancreatic ductal adenocarcinoma (PDA), it remains unclear how Leukemia inhibitory factor (LIF), a cytokine of the IL-6 class family, influences tumor initiation and progression in PDA. LIF is highly upregulated in PDA when compared to the normal healthy pancreas. Using a human single-cell RNAseq PDA data set, we identified pancreatic cancer cells as the main source of LIF, followed by fibroblasts and stellate cells. After confirming that Pdx1-expressing cells represent the majority of Lif-expressing cells in the pancreas, we crossed our newly developed Lif flox/flox allele into the well-established KrasLSL-G12D/+, Trp53flox/flox, Pdx1-Cre (KPC) mouse model. Lif flox/flox, Pdx1-Cre (LC) mice present with normal pancreas histology, mouse weight, and mouse size at 12 months, indicating that Lif is dispensable for mouse pancreas development and function. Lif flox/flox, Trp53flox/flox, Pdx1-Cre (LPC) mice also showed no differences in pancreas histology when compared to normal Lif-expressing PC mice. Lif flox/floxKPC (LKPC) mice develop PDA tumors. Cell lines from LKPC tumors (n=4) presented with undetectable Lif expression and no LIF protein secretion. Control KPC tumor cell lines (n=4) showed Lif expression and LIF secretion, confirming the successful deletion of Lif in our newly developed mouse model. LKPC mice (n=21) showed a significant increase in disease-specific overall survival at 72 days when compared to control KPC mice (n=26) at 62 days (p<0.05). When mice reached endpoint, LKPC mice presented with significantly smaller tumors with an average tumor weight of 0.7g compared to KPC control animals with an average tumor weight of 1.3g (p<0.05). In summary, we find that cancer-cell expressed LIF augments tumor growth and shortens disease-specific overall survival, nominating leukemia inhibitory factor depletion as a promising therapeutic target in KRAS-driven pancreatic cancer. Citation Format: Lisa Miller-Phillips, Imene Boukhalfa Hanafi, Sarah Umetsu, Adam Olshen, Ritu Roy, Ashley Kiemen, Man-Tzu Wang, Eric Collisson. Leukemia inhibitory factor fosters tumor growth in KRAS-driven pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B095.

MDM2-p53 mediate a miR-181c-3p/LIF axis to regulate low dose-rate radiation-induced DNA damage in human B lymphocytes

PurposeProlonged exposure to low dose-rate radiation (LDRR) is of growing concern to public health. Recent evidences indicates that LDRR causes deleterious health effects and is closely related to miRNAs. The aim of our study is to investigate the relationship between miRNAs and DNA damage caused by LDRR. Materials and methodsIn this study, we irradiated C57BL/6J mice with 12.5μGy/h dose of γ ray emitted from uranium ore for 8 h a day for 120 days at a total dose of 12 mGy, and identified differentially expressed miRNAs from the mice long-term exposed to LDRR through isolating serum RNAs, constructing small RNA library, Illumina sequencing. To further investigate the role of differential miRNA under LDRR，we first built DNA damage model in Immortal B cells irradiated with 12.5μGy/h dose of γ ray for 28 days at a total dose of 9.4 mGy. Then, we chose the highly conserved miR-181c-3p among 12 miRNA and its mechanism in alleviating DNA damage induced by LDRR was studied by transfection, quantitative PCR, luciferase assay, and Western blot. Results and conclusionsWe have found that 12 differentially expressed miRNAs including miR-181c-3p in serum isolated from irradiated mice. Analysis of GO and KEGG indicated that target genes of theses 12 miRNA enriched in pathways related to membrane, protein binding and cancer. Long-term exposure to LDRR induced upregulation of gamma-H2A histone family member X (γ-H2AX) expression, a classical biomarker for DNA damage in B cells. miR-181c-3p inhibited Leukemia inhibitory factor (LIF) expression via combining its 3‘UTR. LIF, MDM2, p53, and p-p53-s6 were upregulated after exposure to LDRR. In irradiated B cells, Transfection of miR-181c-3p reduced γ-H2AX expression and suppressed LIF and MDM2 protein levels, whereas p-p53-s6 expression was increased. As expected, the effect of LIF inhibition on irradiated B cells was similar to miR-181c-3p overexpression. Our results suggest that LDRR alters miRNA expression and induces DNA damage. Furthermore, miR-181c-3p can alleviate LDRR-induced DNA damage via the LIF/MDM2/p-p53-s6 pathway in human B lymphocytes. This could provide the basis for prevention and treatment of LDRR injury.

Electroacupuncture combined with bone marrow mesenchymal stem cell transplantation promotes repair of thin endometrium by regulating SDF-1/CXCR4 signaling

It is to explore, based on stromal cell derived factor 1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) signal axis, whether the electroacupuncture (EA) combined with bone marrow mesenchymal stem cells (BMSCs) transplantation can promote thin endometrium regeneration and improve endometrial receptivity, so as to further study its mechanisms underlying improvement of promoting BMSCs homing to repair thin endometrium. Thirty matured female SD rats were randomly divided into normal control , model , BMSCs transplantation (BMSCs), BMSCs+AMD3100 (a specific antagonist of CXCR4, BMSCs+AMD3100), BMSCs+EA, and BMSCs+EA+AMD3100 groups, with 5 rats in each group. The thin endometrial model was established by intrauterine injection of 95% ethanol during the period of estrus. Rats of the model group received intravenous injection of PBS solution (tail vein) on day 1, 3 and 7 of modeling and intraperitoneal injection of normal saline once daily for 3 estrous cycles. Rats of the BMSCs group received intravenous injection of BMSCs suspension on day 1,3 and 7 of modeling, and those of the BMSCs+EA group received BMSCs transplantation and EA stimulation. EA (2 Hz/15 Hz, 1 mA) was applied to "Guanyuan" (CV4) and bilateral "Sanyinjiao"(SP9), "Zigong" (EX-CA1) for 15 min, once daily for 3 estrous cycles. Rats of the BMSCs+AMD3100 group received intravenous injection of BMSCs suspension (1×106/mL) and intraperitoneal injection of AMD3100 (5 mg/kg), and those of the BMSCs+EA+AMD3100 group received administration of BMSCs, AMD3100 and EA, with both groups being once daily for 3 estrous cycles. H.E. staining was used to observe histopathological changes of endometrium tissues, and immunohistochemistry was used to detect the expressions of cytokeratin (CK19) and vimentin in endometrium (for evaluating the damage and repair of endometrium). The expression levels of homeobox A10 (HOXA10), leukemia inhibitory factor (LIF), SDF-1 and CXCR4 proteins were detected by Western blot, and those of SDF-1 and CXCR4 mRNAs in the endometrium detected by real-time PCR. In comparison with the normal control group, the number of endometrial glands, the immunoactivity of CK19 and vimentin, the expression leve-ls of HOXA10, LIF and CXCR4 proteins and CXCR4 mRNA were significantly down-regulated (P<0.01), and the expression levels of SDF-1 protein and mRNA significantly up-regulated (P<0.05) in the model group. Compared with the model group, the number of endometrial glands, the immunoactivity of CK19 and vimentin, and the expression levels of HOXA10, LIF, CXCR4 proteins and CXCR4 mRNA in the BMSCs group, and the number of endometrial glands, the immunoactivity of CK19 and vimentin, the expression levels of HOXA10, LIF, CXCR4 proteins and CXCR4 mRNA, and SDF-1 protein and mRNA in the BMSCs+EA group were significantly up-regulated (P<0.05, P<0.01). Compared to the BMSCs group, the number of endometrial glands, and the expression levels of LIF, CXCR4 proteins and CXCR4 mRNA in the BMSCs+EA group were up-regulated (P<0.01, P<0.05)； the number of endometrial glands, the immunoactivity of CK19 and vimentin, the expression levels of HOXA10, LIF, CXCR4 proteins and CXCR4 mRNA in the BMSCs+AMD3100 group were down-regulated (P<0.01). Compared to the BMSCs+EA group, the number of endometrial glands, the immunoactivity of CK19 and vimentin, the expression levels of HOXA10, LIF, CXCR4 proteins and CXCR4 mRNA in the BMSCs+EA+AMD3100 group were down-regulated (P<0.01). Results of H.E. staining showed thin endometrium with absence of epithelial cells, and sparse glands and blood vessels, with smaller glandular cavity in the model group, which was relative milder in BMSCs and BMSCs+EA groups. EA can promote the transfer of transplanted BMSCs to the damaged site through SDF-1/CXCR4 signaling related stem cell homing, thereby promoting thin endometrial regeneration, repairing endometrial injury, and improving endometrial tolerance in rats with thin endometrium.

Exploring the Potential of Azo Compounds in Leukemia Treatment: Synthesis and Characterization of New Derivatives with Dimedone and Meldrum's Acid End Groups

AbstractThis scholarly investigation presents pioneering drug candidates for combating leukemia, distinguished by reduced side effects and elevated efficacy. The study focuses on azo compounds for their selective targeting against cancerous cells, and customizable properties. Novel azo compounds, DMTPC and DMTPD, were skillfully synthesized via diazotization of 3‐(4‐Methyl‐1H‐imidazol‐1‐yl)‐5‐(trifluoromethyl)aniline with dimedone and meldrum‘s acid. Comprehensive characterization employed advanced analytical techniques like 1H‐NMR, 13C‐NMR, LC‐MS, FT‐IR, and XRD. UV‐Vis and fluorescence spectrophotometers scrutinized absorption and fluorescence properties in diverse solvents. Theoretical DFT computations provided optimized geometries, vibrational frequencies, NMR chemical shifts, absorption wavelengths, HOMOs‐LUMOs, Mulliken charges, and molecular orbital energies. Encouragingly, experimental and theoretical values aligned well. ADME properties and toxicity profiles were evaluated using online web servers. Molecular dynamics simulations explored interactions of DMTPC and DMTPD with the leukemia inhibitory factor protein (PDB ID: 1EMR) compared to Nilotinib. Molecular docking studies indicated DMTPC′s promising potential with a binding energy of −8.8 kcal/mol, approaching Nilotinib's −9.4 kcal/mol. This investigation accentuates the burgeoning research paradigm of exploiting azo compounds in the formidable battle against leukemia, opening new avenues for breakthroughs in this field.

The Role of Leukemia Inhibitory Factor in Counteracting the Immunopathology of Acute and Chronic Lung Inflammatory Diseases

Leukemia inhibitory factor (LIF), a member of the IL-6 cytokine family, is highly expressed throughout the body in multiple tissues and cell types. LIF is primarily known to induce the differentiation of myeloid leukemia cells, but recent studies show that LIF has many other functions, including playing multiple roles in cancer and normal physiology. LIF expression is linked to cellular proliferation, metastasis, inflammation, and chemoresistance. LIF expression and secretion are triggered by many means and its downstream signaling can vary based on tissue types. Recent publications suggest that LIF may play a role in pulmonary diseases and its regulation is altered through external factors, such as cigarette smoke, inflammation stimuli, or infections. This review outlines the current knowledge of the function of LIF protein, mediators of LIF expression, receptors it interacts with, downstream LIF signaling, and possible pulmonary outcomes mediated by LIF.

The dysregulation of leukemia inhibitory factor and its implications for endometriosis pathophysiology.

Endometriosis is an estrogen dominant, chronic inflammatory disease characterized by the growth of endometrial-like tissue outside of the uterus. The most common symptoms experienced by patients include manifestations of chronic pelvic pain- such as pain with urination, menstruation, or defecation, and infertility. Alterations to Leukemia Inhibitory Factor (LIF), a cytokine produced by the luminal and glandular epithelium of the endometrium that is imperative for successful pregnancy, have been postulated to contribute to infertility. Conditions such as recurrent implantation failure, unexplained infertility, and infertility associated diseases such as adenomyosis and endometriosis, have demonstrated reduced LIF production in the endometrium of infertile patients compared to fertile counterparts. While this highlights the potential involvement of LIF in infertility, LIF is a multifaceted cytokine which plays additional roles in the maintenance of cell stemness and immunomodulation. Thus, we sought to explore the implications of LIF production within ectopic lesions on endometriosis pathophysiology. Through immunohistochemistry of an endometrioma tissue microarray and ELISA of tissue protein extract and peritoneal fluid samples, we identify LIF protein expression in the ectopic lesion microenvironment. Targeted RT qPCR for LIF and associated signaling transcripts, identify LIF to be significantly downregulated in the ectopic tissue compared to eutopic and control while its receptor, LIFR, is upregulated, highlighting a discordance in ectopic protein and mRNA LIF expression. In vitro treatment of endometriosis representative cell lines (12Z and hESC) with LIF increased production of immune-recruiting cytokines (MCP-1, MCP-3) and the angiogenic factor, VEGF, as well as stimulated tube formation in human umbilical vein endothelial cells (HUVECs). Finally, LIF treatment in a syngeneic mouse model of endometriosis induced both local and peripheral alterations to immune cell phenotypes, ultimately reducing immunoregulatory CD206+ small peritoneal macrophages and T regulatory cells. These findings suggest that LIF is present in the ectopic lesions of endometriosis patients and could be contributing to lesion vascularization and immunomodulation.

Possible Role of Leukemia Inhibitory Factor and Inflammatory Cytokines in The Recurrent Spontaneous Abortion: A Case-Control Study.

Despite of long-lasting efforts, in more than 50% of cases, the etiology of recurrent spontaneous abortion (RSA) remains unknown. Leukemia inhibitory factor (LIF) has an essential role in the reproductive process, such as modulating inflammatory responses. This study aimed to evaluate the relationship between the LIF gene expression as well as serum levels of inflammatory cytokines and occurrence of RSA in infertile women with a history of RSA. In this case-control study, the relative gene expression levels of LIF, concentrations of tumor necrosis factor-alpha (TNF-α), and interleukin (IL)-17 were measured in peripheral blood and serum of women with a history of RSA (N=40) compared with non-pregnant and fertile women as the control group (N=40) using quantitative real-time polymerase chain reaction and the enzyme-linked immunosorbent assay, respectively. The mean age of patients and controls was 30.1 ± 4.28 and 30.03 ± 4.23, respectively. Patients had a history of at least 2 and at most 6 abortions. The mRNA levels of LIF were significantly lower in the women with RSA in comparison with the healthy participant (P=0.003). Regarding cytokine levels, no significant difference was seen between the two groups (P≥0.05). There was no correlation - between the LIF mRNA levels and TNF-α and IL-17 serum concentrations. The U-Mann-Whitney test and the Pearson correlation coefficient were applied to comparison variables between groups as well as a correlation between LIF mRNA and cytokine levels in serum. Despite a significant reduction in the LIF gene mRNA level in patients with RSA, it was not associated with increases in inflammatory cytokines. Dysfunction in the production of LIF protein may be involved in the onset of RSA disorder.

P215 Deep immune phenotyping of unconventional T cells reveals a depletion in Mucosa Associated T Cells (MAIT) in IBD patients with extraintestinal manifestations

Abstract Background Extraintestinal manifestations (EIM) are common in IBD and they affect importantly the quality of life of patients. Although the pathogenesis of EIM is still poorly understood, an altered immune response involving T cells has been proposed. In addition, the presence of EIM during disease course will impact the therapeutic choices with new biologics. In the present work we aim to characterize T cell populations -with focus on Uncoventional T cells- in IBD patients presenting EIM using advance flow cytometry and proteomics. Methods A total of 184 individuals (106 F/78 M) and were prospectively included: 149 IBD patients (84 UC/65 CD) and 25 healthy matched controls. Biologic samples including Peripheral Blood Mononuclear Cells (PBMC) and plasma were consecutively stored and classified in an established cross sectional IBD biobank at the Norwegian University of Science and Technology. Patient characteristics including age, sex, smoking status, current medication, Montreal Classification phenotype and inflammation biomarkers (CRP) and fecal Calprotectin were recorded. PBMC were stained with antibodies and acquired using BD FACS Symphony flow cytometer using automatic compensations and Multiplex ELISA for 65 proteins was performed using Immune Monitoring 65-Plex Human ProcartaPlex™ Panel at Singapore Immunology Network (SIgN), as previously described. Statistical analysis was performed using GraphPad Prism (San Diego, CA). p≤ 0.05 was considered statistically significant. Results Of the 184 IBD patients included, the presence or not of EIM was registered in 149 (mean age 37 +/-7.2; 86 female) of which 84 had UC and 65 CD. Of them, 21 (14.1%) presented EIM at inclusion. We analyzed the differences in all subsets of unconventional T cells: gammadelta T cells (VD1, VD2, VD3), MAIT cells, innate NKT cells and CD4/CD8 positive T cells between IBD patients with or without EIM (Fig1A). MAIT cells were selectively depleted in patients with EIM (p&amp;lt;0.01), while there was no statistically significant change in the ratios of other T cell subpopulations. We then studied the concentrations of plasma proteins between the two groups. We found a significant increase in IL-2, GM-CSF, IL-6, Eotaxin, Leukemia Inhibitory Factor Protein (LIF), TNF-RII and Monocyte Chemoattractant Protein-1 (MCP), all p&amp;lt;0.05 in patients with EIM (Fig1B). In order to address the potential use of MAIT as marker of EIM we constructed a ROC curve showing an AUC 0.752 (95% CI 0.639-0.865, p= 0.0002) Fig. 1C Conclusion MAIT cell depletion associated strongly with the presence of EIM and could be used as a clinical marker for EIM in IBD. A deeper understanding of its role in the pathogenesis of EIM, as well as an external validation as a marker, deserves further investigation.

Comparison of the effects of buffalo LIF and mouse LIF on the in vitro culture of buffalo spermatogonia.

Leukemia inhibitory factor (LIF) is an important growth factor that supports the culture and maintenance of spermatogonial stem cells (SSCs) by suppressing spontaneous differentiation. Different LIF sequences may lead to differences in function. The protein sequences of buffalo LIF and mouse LIF differed by 65.5% according to MEGA software analysis. The PB-LIF-GFP-Puro vector was constructed, and the CHO-K1 cell line was established. The final LIF protein concentration in the CHO-K1 cell culture medium was approximately 4.268 ng/mL. Here, we report that buffalo LIF effectively maintains the self-renewal of buffalo spermatogonia during culture. Buffalo spermatogonia were cultured in conditioned medium containing no LIF (0 ng/mL), mouse LIF (1 ng/mL), mouse LIF (10 ng/mL), or buffalo LIF (1 ng/mL). Furthermore, the effects of mouse LIF and buffalo LIF culture on the maintenance of buffalo spermatogonia were determined by analyzing cell colony formation, quantitative real-time polymerase chain reaction, cell immunofluorescence, and cell counting. The buffalo LIF (1 ng/mL) group showed similar maintenance of the proliferation of buffalo spermatogonia to that in the mouse LIF (10 ng/mL) group. These results demonstrated that the proliferation of buffalo spermatogonia can be maintained in vitro by adding a low dose of buffalo LIF. This study provides a foundation for the further optimization of in vitro buffalo SSC culture systems.

Leukemia inhibitory factor protects against graft-versus-host disease while preserving graft-versus-leukemia activity

AbstractGraft-versus-host disease (GVHD) remains a major complication after allogeneic hematopoietic stem cell transplantation, a widely used therapy for hematologic malignancies and blood disorders. Here, we report an unexpected role of cytokine leukemia inhibitory factor (LIF) in protecting against GVHD development. Administrating recombinant LIF protein (rLIF) protects mice from GVHD-induced tissue damage and lethality without compromising the graft-versus-leukemia activity, which is crucial to prevent tumor relapse. We found that rLIF decreases the infiltration and activation of donor immune cells and protects intestinal stem cells to ameliorate GVHD. Mechanistically, rLIF downregulates IL-12–p40 expression in recipient dendritic cells after irradiation through activating STAT1 signaling, which results in decreased major histocompatibility complex II levels on intestinal epithelial cells and decreased donor T-cell activation and infiltration. This study reveals a previously unidentified protective role of LIF for GVHD-induced tissue pathology and provides a potential effective therapeutic strategy to limit tissue pathology without compromising antileukemic efficacy.

Yikang decoction facilitates embryo implantation in mice with implantation dysfunction via upregulation of LIF expression

ObjectiveThe present study investigates the effects and mechanisms of Yikang decoction on embryo implantation in mice. MethodsTotally, mature female mice were randomly divided into four groups: normal, implantation failure (mifepristone treatment), Yikang decoction treatment (mifepristone and Yikang decoction treatment), and control (mifepristone and physiological saline treatment) groups. The efficacy of Yikang decoction was evaluated by the adhesion of uterine endometrial cells. The expression of leukemia inhibitory factor (LIF) and integrin αvβ3 in the endometrium were detected by real-time quantitative PCR and western blot. In addition, mouse endometrial cells were transfected with LIF specific siRNA-1, and the expression of LIF and αvβ3 were detected. ResultsThe number of embryos markedly decreased after mifepristone treatment. The adhesion of endometrial cells in the Yikang decoction treatment group significantly increased, when compared to the control group. The expression of LIF and integrin αvβ3 was significantly reduced by mifepristone, but the attenuated expression of LIF and αvβ3 was markedly reversed by treatment with Yikang decoction. In addition, after LIF siRNA-1 transfection, the expression of integrin αvβ3 significantly decreased (P < 0.01). The correlation analysis revealed a significant positive correlation between LIF and αvβ3 protein expression. ConclusionYikang decoction can regulate the expression of αvβ3 and increase cell adhesion by upregulating the expression of LIF, thereby improving embryo implantation in mice. These data suggest that Yikang decoction may have therapeutic effect in treating infertility.

Role of three-dimensional Doppler ultrasonography and leukemia inhibitory factor from endometrial secretion in predicting endometrial receptivity in IVF treatment: a pilot study

PurposeThis pilot study aimed to evaluate the potential synergistic role of three-dimensional power Doppler angiography ultrasound and the expression of Leukemia Inhibitory Factor (LIF) protein in predicting the endometrial receptivity of fresh In-Vitro Fertilization (IVF) cycles.Materials and methodsThis prognostic cohort study involved 29 good prognosis women who underwent fresh IVF cycles with fresh blastocysts transfer. Serial measurements of sub-endometrial parameters including vascularity index (VI), flow index (FI), and vascularization flow index (VFI) were conducted consecutively via power Doppler angiography on the day of oocyte maturation trigger, oocyte retrieval, and blastocyst transfer. Aspiration of endometrial secretion was performed on the day of embryo transfer.ResultsThe mean index of VI and VFI on the trigger and oocyte retrieval day and also LIF protein concentration at the window of implantation were significantly higher in clinically pregnant women than that of the non-pregnant women (p < 0.05). The area under the curve (AUC) of VI and VFI was shown to have a powerful predictive value to forecast receptive endometrium on either trigger day (0.788 and 0.813, respectively) or oocyte retrieval day (0.813 and 0.818). Likewise, LIF concentration on the day of embryo transfer was adequate to become a predictor for endometrial receptivity (AUC 0.874). A combination of the VI and VFI on the trigger day and LIF concentration at specific cut-off values (VI > 5.381, VFI > 1.483, LIF 703.5 pg/mL) produced an algorithm with high AUC (0.881) and high specificity (94.4%) for an adequate prediction of non-receptive endometrium.ConclusionVI and VFI index assessed on maturation trigger day and the expression of LIF protein concentration at the window of implantation provided sufficient information to predict endometrial receptivity. A large randomized control trial is needed to validate these findings.

Leukemia Inhibitory Factor Promotes Survival of Hematopoietic Progenitors Ex Vivo and Is Post-Translationally Regulated by DPP4.

Hematopoietic cells are regulated in part by extracellular cues from cytokines. Leukemia inhibitory factor (LIF) promotes survival, self-renewal, and pluripotency of mouse embryonic stem cells (mESC). While genetic deletion of LIF affects hematopoietic progenitor cells (HPCs), the direct effect of LIF protein exposure on HPC survival is not known. Furthermore, post-translational modifications (PTM) of LIF and their effects on its function have not been evaluated. We demonstrate that treatment with recombinant LIF preserves mouse and human HPC numbers in stressed conditions when growth factor addition is delayed ex vivo. We show that Lif is upregulated in response to irradiation-induced stress. We reveal novel PTM of LIF where it is cleaved twice by dipeptidyl peptidase 4 (DPP4) protease so that it loses its 4 N-terminal amino acids. This truncation of LIF down-modulates LIF's ability to preserve functional HPC numbers ex vivo following delayed growth factor addition. DPP4-truncated LIF blocks the ability of full-length LIF to preserve functional HPC numbers. This LIF role and its novel regulation by DPP4 have important implications for normal and stress hematopoiesis, as well as for other cellular contexts in which LIF and DPP4 are implicated.

Cancer-Associated Fibroblasts Regulate the Plasticity of Breast Cancer Stemness through the Production of Leukemia Inhibitory Factor

Simple SummaryCancer-associated fibroblasts (CAFs; as components of cancer stroma) use different signaling pathways to promote tumor progression and growth, invasion, and metastasis in diverse cancers. They have crosstalk with cancer cells during tumor progression. To investigate this crosstalk, in this study, a coculture system of CAF cells isolated from breast cancer patients with breast cancer cells was used to investigate leukemia inhibitory factor (LIF) production from CAFs. LIF is a signaling molecule that activates distinct signaling pathways through which cell cycle progression, cell death, adhesion, migration, and tumorigenesis are regulated.Leukemia inhibitory factor (LIF), as a member of the interleukin-6 cytokine family, plays a complex role in solid tumors. However, the effect of LIF as a tumor microenvironment factor on plasticity control in breast cancer remains largely unknown. In this study, an in vitro investigation is conducted to determine the crosstalk between breast cancer cells and fibroblasts. Based on the results, cancer-associated fibroblasts are producers of LIF in the cocultivation system with breast cancer cells. Treatment with the CAF-CM and human LIF protein significantly promoted stemness through the dedifferentiation process and regaining of stem-cell-like properties. In addition, the results indicate that activation of LIFR signaling in breast cancer cells in the existence of CAF-secreted LIF can induce Nanog and Oct4 expression and increase breast cancer stem cell markers CD24−/CD44+. In contrast, suppression of the LIF receptor by human LIF receptor inhibition antibody decreased the cancer stem cell markers. We found that LIF was frequently overexpressed by CAFs and that LIF expression is necessary for dedifferentiation of breast cancer cell phenotype and regaining of cancer stem cell properties. Our results suggest that targeting LIF/LIFR signaling might be a potent therapeutic strategy for breast cancer and the prevention of tumor recurrence.

Leukemia inhibitory factor is involved in the pathogenesis of NSCLC through activation of the STAT3 signaling pathway.

Leukemia inhibitory factor (LIF) is a tumor promoter in several cancer types. However, the role of LIF in non-small cell lung cancer (NSCLC) remains to be explored. The present study explored the hypothesis that LIF is important for NSCLC development by measuring LIF expression and its downstream signal transducer and activator of transcription 3 (STAT3) phosphorylation in tumor samples derived from patients with NSCLC. The association between LIF expression and clinical features was analyzed in two cancer subtypes. The effects of LIF on cell proliferation, migration and invasion were also evaluated in a NSCLC-derived cell line, A549. LIF mRNA and protein expression levels were significantly higher in tumor tissues compared with those in the corresponding adjacent and normal lung tissues. Regarding NSCLC subtypes, LIF expression was significantly higher in adenocarcinoma than in squamous cell carcinoma tissues. It was also found that phosphorylated-STAT3 levels were higher in tumor tissues compared with those in the corresponding adjacent and normal lung tissues, which was in agreement with the LIF expression levels in NSCLC tissues. Clinically, overexpression of LIF was positively correlated with aggressive tumor characteristics, including lymph node metastasis and advanced tumor stage. In A549 cells, LIF treatment enhanced cell proliferation, migration and invasion. LIF also increased STAT3 phosphorylation in A549 cells, and the STAT3 inhibitor Stattic decreased A549 cell migration and invasion following LIF stimulation. The present results demonstrate that LIF is overexpressed in NSCLC, and that LIF can promote NSCLC development through activation of the STAT3 signaling pathway. The present study indicates that LIF may serve as a potential prognostic marker for NSCLC.

Investigation into the effects of leukemia inhibitory factor on the bone repair capacity of BMSCs-loaded BCP scaffolds in the mouse calvarial bone defect model.

Leukemia inhibitory factor (LIF) is known to play a major role in bone physiology. In the present study, we examined the in vitro effects of LIF on osteoblast differentiation of bone marrow stem cells (BMSCs) and explored in vivo effects of LIF on the bone repair capacity of BMSCs-loaded biphasic calcium phosphate (BCP) scaffolds in mouse calvarial bone defect model. The mRNA and protein expression levels in the BMSCs were determined by quantitative real-time PCR and western blot, respectively; the in vitro osteoblast differentiation of the BMSCs was evaluated by using Alizarin Red S staining. The bone volume and bone density in the repaired calvarial bone defect were determined by Micro-CT. Bone regeneration was also histologically evaluated by hematoxylin and eosin staining and Masson's trichrome staining. Hypoxia treatment induced the up-regulation of Lif mRNA and LIF protein in the BMSCs. Lif overexpression up-regulated the mRNA expression levels of osteopontin and Runt-related transcription factor 2, and increased intensity of Alizarin Red S staining in the BMSCs; while Lif silence exerted the opposite effects. The in vivo studies showed that implantation of Lif-overexpressing BMSCs-loaded BCP scaffolds significantly increased the bone volume and bone density at 4 and 8weeks after transplantation, and promoted the regeneration of bone tissues in the mouse calvarial bone defect at 8weeks after transplantation when compared to the BMSCs-loaded BCP scaffolds group; while Lif-silencing BMSCs-loaded BCP scaffolds had the opposite effects. The present study for the first time demonstrated that LIF promoted the in vitro osteoblast differentiation of hypoxia-treated BMSCs; and further studies revealed that LIF exerted enhanced effects on the bone repair capacity of BMSCs-load BCP scaffolds in mouse calvarial bone defect model. However, future studies are warranted to determine the detailed mechanisms of LIF in the large-scale bone defect repair.

Leukemia inhibitory factor regulates Schwann cell proliferation and migration and affects peripheral nerve regeneration

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that stimulates neuronal development and survival. Our previous study has demonstrated that LIF mRNA is dysregulated in the peripheral nerve segments after nerve injury. Here, we show that LIF protein is abundantly expressed in Schwann cells after rat sciatic nerve injury. Functionally, suppressed or elevated LIF increases or decreases the proliferation rate and migration ability of Schwann cells, respectively. Morphological observations demonstrate that in vivo application of siRNA against LIF after peripheral nerve injury promotes Schwann cell migration and proliferation, axon elongation, and myelin formation. Electrophysiological and behavior assessments disclose that knockdown of LIF benefits the function recovery of injured peripheral nerves. Differentially expressed LIF affects the metabolism of Schwann cells and negatively regulates ERFE (Erythroferrone). Collectively, our observations reveal the essential roles for LIF in regulating the proliferation and migration of Schwann cells and the regeneration of injured peripheral nerves, discover ERFE as a downstream effector of LIF, and extend our understanding of the molecular mechanisms underlying peripheral nerve regeneration.

Contraceptive and molecular function of a novel recombinant vaccine based human leukemia inhibitory factor on Balb/c mice: An experimental in vivo study

The functional competence of leukemia inhibitory factor (LIF), as immunocontraceptive vaccine in mice, was investigated. Balb/c mice were divided into two groups of vaccinated and controls. The recombinant human LIF (rhLIF) protein and phosphate buffer saline was emulsified with Freund's adjuvant and injected into vaccinated and control groups, respectively. Theinhibition of implantation was evaluated in mice uterine. The concentration of secreted interferon-γ (IFN-γ) and interleukin (IL)-4 were measured in cultured splenocyte of mice stimulated by rhLIF. The expressions of immune responsive gene 1 (IRG-1), cochlin (COCH), amphiregulin(Ar), and heparin-binding EGF-like growth factor (HB-EGF) genes were determined. Mice were assessed for inhibition of fertility after delivery, reversibility of immune response against rhLIF, and survival rate. Active immunization of mice with rhLIF resulted in reduction of the implantation and fertility rate up to 80.49% and 75%, respectively. All mice produced a high titer of anti-rhLIF antibodies in serums and vaginal fluids washes after 16 weeks; however, these antibodies were cleared from vaginal fluid washes after six months. A significant down-regulation in mRNA levels of IRG-1, Ar and HB-EGF was observed in vaccinated group compared to controls; however, no significant change in the expression profile of cochlin gene was detected. The results showed that rhLIF prevented pregnancy in a high percentage of female mice. Although the immunization of female Balb/c mice with rhLIF inhibited fertility and expression of genes associated with this molecule, further studies are needed to support this protein as a suitable candidate for contraceptive vaccine in mammals.

Leukemia Inhibitory Factor Participates in the Formation of Stress Adaptation via Hippocampal Myelination in Mice

Leukemia inhibitory factor (LIF) has been shown to be involved in myelination. The present study investigated whether LIF plays a significant role in the formation of stress adaptation using stress-adaptive and -maladaptive mice, and also attempted to confirm whether there was any difference in myelination between these animal models. A single exposure to restraint stress for 1 h induced a decrease in head-dipping behavior in the hole-board test. This stress response was not seen in mice that had been exposed to restraint stress for 1 h/day for 14 days, which is referred to as stress adaptation. In contrast, repeated exposure to restraint stress for 4 h/day for 14 days did not lead to the development of stress adaptation, and was still associated with a decrease in head-dipping behaviors. Under these conditions, LIF protein was found to be increased with astrocyte activation in the hippocampus of stress-adaptive mice, whereas no change was observed in stress-maladaptive mice. On the other hand, major myelin proteins including myelin-associated glycoprotein and myelin basic protein, as well as mature oligodendrocytes, were decreased in the hippocampus of stress-maladaptive, but not stress-adaptive, mice. Furthermore, while the levels of phosphorylated-extracellular signal-regulated kinase (p-ERK) were increased in the hippocampus of stress-adaptive, this change did not occur in stress-maladaptive mice. Taken together, the present findings suggest that LIF, which may be derived from activated astrocytes, plays a critical role in the maintenance of hippocampal myelination via an ERK signaling pathway, and contributes to the development of stress adaptation.

Abstract 304: Androgen deprivation induces epithelial to mesenchymal transition and neuroendocrine differentiation of prostate cancer via LIF-mediated phosphorylation of Smad2

Abstract The current therapies for prostate cancer, which can either be androgen-sensitive or androgen-insensitive ones, are based on AR-targeting approaches; however, there is no available treatment for neuroendocrine prostate cancer (NEPC). We previously identified the leukemia inhibitory factor (LIF), which is stimulated by androgen deprivation therapy (ADT). Here, we further elucidated the physiological relevance of LIF, whereby the high LIF output is associated with the activation of epithelial-to-mesenchymal transition (EMT), and neuroendocrine differentiation of prostate cancer cells through stimulation of transforming growth factor (TGF)-β signaling. We have elucidated the effect of LIF on inducing the EMT and NEPC progression through the stimulated TGF-β signaling via phosphorylation of Smad2. We also demonstrated that the inverse relationship between inhibition of AR signaling and induction of LIF-Smad2 signaling may predispose prostate cancer to metastasis. Importantly, an established activation in prostate cancer cells was shown between recombinant LIF protein and phosphorylation of Smad2, supporting the connection between LIF and p-Smad2. This was supported by the results obtained in high-LIF samples with elevated expression of p-Smad2 in tissues from high-grade prostate cancer. This study highlights the role of the important crosstalk between the LIF and TGF-β signaling pathways may exist and provide a new direction for investigating NEPC development. Citation Format: Yen-Nien Liu, Shian-Ren Lin, Ntlotlang Mokgautsi, Hsiu-Lien Yeh, Jiaoti Huang. Androgen deprivation induces epithelial to mesenchymal transition and neuroendocrine differentiation of prostate cancer via LIF-mediated phosphorylation of Smad2 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 304.