Targeting leukemia inhibitory factor in pancreatic adenocarcinoma.

INTRODUCTION: The Leukemia Inhibitory Factor (LIF) is a member of the interleukin-6 (IL-6) cytokine family. Known to induce differentiation of myeloid leukemia cells, evidence has accumulated supporting its role in cancer evolution through regulating cell differentiation, renewal, and survival. LIF has recently emerged as a biomarker and therapeutic target for pancreatic ductal adenocarcinoma (PDAC). The first in-human clinical trial has shown promising safety profile and has suggested a potential role for LIF inhibitor in combination regimen. AREAS COVERED: Herein, we summarize, discuss, and give an expert opinion on the role of LIF in PDAC promotion, and its potential role as a biomarker and target of anti-cancer therapy. We conducted an exhaustive PubMed search for English-language articles published from 1 January 1970, to 1 August 2022. EXPERT OPINION: PDAC carries a devastating prognosis for patients, highlighting the need for advancing drug development. The results of the phase 1 trial with MSC-1 demonstrated tolerability and safety but modest efficacy. Future research should focus on investigating LIF targets in combination with current standard-of-care chemotherapy, and immunotherapy can be a promising approach. Further, larger multicenter clinical trials are needed to define the use of LIF as a new biomarker in PDAC patients.

Antidepressant effects of Enterococcus faecalis 2001 through the regulation of prefrontal cortical myelination via the enhancement of CREB/BDNF and NF-κB p65/LIF/STAT3 pathways in olfactory bulbectomized mice.

A therapeutic strategy through the gut-brain axis has been proven to be effective in treatment for depression. In our previous study, we demonstrated that Enterococcus faecalis 2001 (EF-2001) prevents colitis-induced depressive-like behavior through the gut-brain axis in mice. More recently, we found that demyelination in the prefrontal cortex (PFC) was associated with depressive-like behavior in an animal model of major depressive disorder, olfactory bulbectomized (OBX) mice. The present study investigated the effects of EF-2001 on depressive-like behaviors in OBX mice and the underlying molecular mechanisms from the perspective of myelination in the PFC. OBX mice exhibited depressive-like behaviors in the tail-suspension, splash, and sucrose preference tests, and decreased myelin and paranodal proteins along with mature oligodendrocytes in the PFC. These behavioral and biochemical changes were all prevented by treatment with EF-2001. Further, EF-2001 treatment increased brain-derived neurotrophic factor (BDNF) and leukemia inhibitory factor (LIF) in the PFC. Interestingly, an immunohistochemical analysis revealed enhanced phospho (p) -cAMP-responsive element binding protein (CREB) expression in neurons, p-nuclear factor-kappa B (NFκB) p65 (Ser536) expression in astrocytes, and p-signal transducer and activator of transcription 3 (STAT3) (Ty705) expression in mature oligodendrocytes in the PFC of OBX mice. From these results, we suggest that EF-2001 administration prevents depressive-like behaviors by regulating prefrontal cortical myelination via the enhancement of CREB/BDNF and NFκB p65/LIF/STAT3 pathways. Our findings strongly support the idea that a therapeutic strategy involving the gut microbiota may be a promising alternative treatment for alleviating symptoms of depression.

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 8 weeks after transplantation, and promoted the regeneration of bone tissues in the mouse calvarial bone defect at 8 weeks 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: Recent advances and implications in biotechnology.

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine with several functions in health and disease ranging from inflammation to cancer. LIF is also a potential target and/or therapeutic agent for diseases such as multiple sclerosis, stroke and even psychological disorders, where the function of LIF as a neurotrophic factor has only recently been explored. In recent years, a limited number of LIF clinical trials have been completed, which partially explains the shortage of effective applications as a therapeutic agent. With the increasing interest from biotechnology companies producing recombinant LIF, this status quo will certainly change, and the potential impact of LIF in terms of disease diagnosis, treatment and management will be realized.

Leukemia inhibitory factor modulates the peripheral immune response in a rat model of emergent large vessel occlusion.

BACKGROUND: The migration of peripheral immune cells and splenocytes to the ischemic brain is one of the major causes of delayed neuroinflammation after permanent large vessel stroke. Other groups have demonstrated that leukemia inhibitory factor (LIF), a cytokine that promotes neural cell survival through upregulation of antioxidant enzymes, promotes an anti-inflammatory phenotype in several types of immune cells. The goal of this study was to determine whether LIF treatment modulates the peripheral immune response after stroke. METHODS: Young male (3 month) Sprague-Dawley rats underwent sham surgery or permanent middle cerebral artery occlusion (MCAO). Animals were administered LIF (125 µg/kg) or PBS at 6, 24, and 48 h prior to euthanization at 72 h. Bone marrow-derived macrophages were treated with LIF (20 ng/ml) or PBS after stimulation with interferon gamma + LPS. Western blot was used to measure protein levels of CD11b, IL-12, interferon inducible protein-10, CD3, and the LIF receptor in spleen and brain tissue. ELISA was used to measure IL-10, IL-12, and interferon gamma. Isolectin was used to label activated immune cells in brain tissue sections. Statistical analysis was performed using one-way ANOVA and Student's t test. A Kruskal-Wallis test followed by Bonferroni-corrected Mann-Whitney tests was performed if data did not pass the D'Agostino-Pearson normality test. RESULTS: LIF-treated rats showed significantly lower levels of the LIF receptor and interferon gamma in the spleen and CD11b levels in the brain compared to their PBS-treated counterparts. Fluorescence from isolectin-binding immune cells was more prominent in the ipsilateral cortex and striatum after PBS treatment compared to LIF treatment. MCAO + LIF significantly decreased splenic levels of CD11b and CD3 compared to sham surgery. MCAO + PBS treatment significantly elevated splenic levels of interferon inducible protein-10 at 72 h after MCAO, while LIF treatment after MCAO returned interferon inducible protein 10 to sham levels. LIF administration with interferon gamma + LPS significantly reduced the IL-12/IL-10 production ratio compared to macrophages treated with interferon gamma + LPS alone. CONCLUSIONS: These data demonstrate that LIF promotes anti-inflammatory signaling through alterations of the IL-12/interferon gamma/interferon inducible protein 10 pathway.

Protective Effects of Leukemia Inhibitory Factor on Retinal Vasculature and Cells in Streptozotocin-induced Diabetic Mice.

BACKGROUND: Leukemia inhibitory factor (LIF) has been reported to possess various pharmacological effects, including displaying vascular and neuroprotective properties, during retinal disease. The aim of this study was to investigate the vascular and structural changes in the retina of diabetic mice and to explore whether LIF prevents experimental diabetes-induced retinal injury in the early stages. METHODS: Diabetes was induced in C57Bl/6J mice with streptozotocin (STZ) injections. Successful diabetic animal models were randomly separated into two groups: the diabetic group (n = 15) and the LIF-treated group (n = 15). Normal C57BL/6 mice served as the normal control group (n = 14). Recombinant human LIF was intravitreally injected 8 weeks after the diabetic model was successfully established. Retinas were collected and evaluated using histological and immunohistochemical techniques, and flat-mounted retinas and Western blotting were performed at 18 weeks after the induction of diabetes and 2 days after the intravitreal injection of LIF. The analysis of variance test were used. RESULTS: Histological analysis showed that there were fewer retinal ganglion cells (RGCs) and the inner nuclear layer (INL) became thinner in the diabetic model group (RGC 21.8 ± 4.0 and INL 120.2 ± 4.6 µm) compared with the normal control group (RGC 29.0 ± 6.7, t = -3.02, P = 0.007; INL 150.7 ± 10.6 µm, t = -8.88, P < 0.001, respectively). After LIF treatment, the number of RGCs (26.9 ± 5.3) was significantly increased (t = 3.39, P = 0.030) and the INL (134.5 ± 14.2 µm) was thicker compared to the diabetic group (t = 2.75, P = 0.013). In the anti-Brn-3a-labeled retinas, the number of RGCs in the LIF-treated group (3926.0 ± 143.9) was obviously increased compared to the diabetic group (3507.7 ± 286.1, t = 2.38, P = 0.030), while no significance was found between the LIF-treated group and the control group (4188.3 ± 114.7, t = -2.47, P = 0.069). Flat-mounted retinas demonstrated that a disorganized, dense distribution of the vessel was prominent in the diabetic model group. Vessel distribution in the LIF-treated mouse group was typical and the thickness was uniform. The levels of phosphosignal transducer and activator of transcription 3 activation were obviously higher in the LIF-injected retinas than those in the diabetic control group (t = 3.85, P = 0.019) and the normal control (t = -3.20, P = 0.019). CONCLUSION: The present study provides evidence that LIF treatment protects the integrity of the vasculature and prevents retinal injury in the early stages of diabetic retinopathy in STZ-induced diabetic models.

Leukemia inhibitory factor attenuates renal fibrosis through Stat3-miR-29c.

Leukemia inhibitory factory (LIF), as a member of the IL-6 family, has been reported to ameliorate myocardial fibrosis and myocardial cell death. The purpose of the present study was to investigate the effect of LIF on renal fibrosis and its underlying mechanism. Our results showed, first, that LIF inhibited collagen type 1 and collagen type 3 expression induced by ANG II in NRK-49F (rat kidney fibroblast) cells and in mice with unilateral ureteral obstruction. Second, LIF induced Stat3 Tyr(705) phosphorylation and inhibited Stat3 Tyr(705) and Ser(727) phosphorylation induced by ANG II in NRK-49F cells. Third, LIF exerted an antirenal fibrosis effect mainly through activation of Stat3 Tyr(705) phosphorylation in NRK-49F cells. These effects of LIF were not observed in Stat3(-/-) cells. Finally, LIF-Stat3 upregulated microRNA-29c expression, and the latter downregulated collagen type 1 and collagen type 3 expression in NRK-49F cells and in mice with unilateral ureteral obstruction. In conclusion, LIF played a role in antirenal fibrosis by competitively activating Stat3 Tyr(705) phosphorylation, which upregulated microRNA-29c to suppress collagen expression.

The neuron regrowth is associated with the proliferation of neural precursor cells after leukemia inhibitory factor administration following spinal cord injury in mice.

OBJECTIVES: To explore whether LIF could promote the proliferation of neural precursor cells (NPCs) and to analyze the correlation between increased NPCs and FluoroGold (FG) labeled neurons in mice after spinal cord injury (SCI). METHODS: Motor behavior was assessed using Rotarod and Platform Hang tests; neurons in the corticospinal and rubrospinal systems were labeled with FG, NPCs were immustained with nestin-FITC conjugate. The numbers of FG-labeled neurons and NPCs were estimated, and the correlation between FG-labeled neurons and NPCs was assessed. RESULTS: Mice in the SCI group showed negligible recovery of locomotor behavior; in contrast, mice in the LIF group showed a statically significant improvement. Both FG-labeled neurons and NPCs were significantly increased in the LIF group compared to the SCI group, and this increase in FG-labeled neurons and NPCs showed a clear association above the lesion level. CONCLUSIONS: LIF could promote locomotive behaviors in mice post-SCI by encouraging the proliferation of NPCs; LIF may in fact be a potential cytokine for the induction of NPCs post-SCI.

Leukemia inhibitor factor promotes functional recovery and oligodendrocyte survival in rat models of focal ischemia.

Human umbilical cord blood (HUCB) cells have shown efficacy in rodent models of focal ischemia and in vitro systems that recapitulate stroke conditions. One potential mechanism of protection is through secretion of soluble factors that protect neurons and oligodendrocytes (OLs) from oxidative stress. To overcome practical issues with cellular therapies, identification of soluble factors released by HUCB and other stem cells may pave the way for treatment modalities that are safer for a larger percentage of stroke patients. Among these soluble factors is leukemia inhibitory factor (LIF), a cytokine that exerts pleiotropic effects on cell survival. Here, data show that LIF effectively reduced infarct volume, reduced white matter injury and improved functional outcomes when administered to rats following permanent middle cerebral artery occlusion. To further explore downstream signaling, primary oligodendrocyte cultures were exposed to oxygen-glucose deprivation to mimic stroke conditions. LIF significantly reduced lactate dehydrogenase release from OLs, reduced superoxide dismutase activity and induced peroxiredoxin 4 (Prdx4) transcript. Additionally, the protective and antioxidant capacity of LIF was negated by both Akt inhibition and co-incubation with Prdx4-neutralising antibodies, establishing a role for the Akt signaling pathway and Prdx4-mediated antioxidation in LIF protection.

Functional inclusion bodies produced in bacteria as naturally occurring nanopills for advanced cell therapies.

Inclusion bodies (50-500 nm in diameter) produced in recombinant bacteria can be engineered to contain functional proteins with therapeutic potential. Upon exposure, these protein particles are efficiently internalized by mammalian cells and promote recovery from diverse stresses. Being fully biocompatible, inclusion bodies are a novel platform, as tailored nanopills, for sustained drug release in advanced cell therapies.

Understanding the link between the IL-6 cytokine family and pregnancy: implications for future therapeutics.

Cytokines are involved in almost all processes during the menstrual cycle, the fertilization period and pregnancy. They are expressed in numerous reproduction-related body fluids and tissues. Disorders of cytokine expression patterns may cause pregnancy pathologies. Therefore, cytokines have the potential as new biomarkers in different body compartments for a variety of such pathologies. Furthermore, cytokines may also serve to treat fertility and pregnancy disorders. The IL-6-like family of cytokines is an intensively investigated group of cytokines with well-accepted functions in fertility and pregnancy. This article summarizes current knowledge on IL-6-like cytokines in regard of their role in reproduction and their potential for new strategies in the treatment of reproductive pathologies.

Effect of leukemia inhibitory factor on corneal nerve regeneration of rabbit eyes after laser in situ keratomileusis.

To explore the effect of leukemia inhibitory factor on corneal nerve regeneration in a rabbit model after laser in situ keratomileusis. Thirty five healthy New Zealand rabbits were divided into three groups for a 6-month observation, the blank control group, the control group, and the treatment group respectively. Laser in situ keratomileusis for myopia was performed on 30 rabbits (60 eyes in total) and then 1 µg/ml LIF eye drops were used four times a day on the left eyes as the treatment group, and the balanced salt solution (BSS) was used on the right eyes as the control group. Nerve regeneration was evaluated by counting the new regenerated nerves in golden chloride staining. The parameters for dry eye include Schirmer I test and tear break-up time were also examined. The number of regenerated nerve fibers in the treatment group was significantly higher than that in the control group at all time points except the 6th month after LASIK (P<0.05). The parameters for dry eye between two groups were compared at each postoperative time point and the results showed they were significantly higher in the LIF-treated group than in the BSS-control group at 2w, 1m, and 3m respectively. Leukemia inhibitory factor can effectively accelerate the corneal nerve regeneration of rabbit eyes after LASIK surgery and decrease the occurrence of dry eye symptoms.

LIF in the regulation of T-cell fate and as a potential therapeutic.

At the heart of lineage commitment within the adaptive immune response is the intrinsic genetic plasticity of the naive peripheral T lymphocyte (T cell). Primary activation by presentation of cognate antigen is coupled to rapid T-cell cycling and progressive epigenetic changes that guide the cell down distinct T-cell lineages, either effector (Th1, Th2, Th17) or tolerogenic (Treg). Fate choice is influenced both by strength of the priming activation signal and by cues from the micro-environment that are integrated with lineage-specific gene expression profiles, eventually becoming hard-wired in the fully differentiated cell. The micro-environmental cues include cytokines, and the discovery that leukaemia inhibitory factor (LIF) and interleukin (IL)-6 counter-regulate development of the Treg and Th17 lineages places LIF within the core regulatory circuitry of T cells. I first summarise current understanding of LIF and the LIF receptor in the context of T cells. Next, the central relevance of the LIF/IL-6 axis in immune-mediated disease is set in the context of (i) a new nano-therapeutic approach for targeted delivery of LIF and (ii) MARCH-7, a novel E3-ligase discovered to have a central mechanistic role in LIF-mediated T-cell biology, functioning as a rheostat-type regulator of endogenous LIF-signalling.