Tumor cell-expressed lipolysis-stimulated lipoprotein receptor negatively regulates T-cell function.

Lipolysis-stimulated lipoprotein receptor (LSR) is known as a lipoprotein receptor. LSR is expressed in various solid tumors, including epithelial ovarian, gastric, and colon cancers. High LSR expression is significantly associated with poor prognosis, but its role in cancer has not been fully elucidated. LSR belongs to the Ig protein superfamily, which is conserved in B7 family. Here, we assessed LSR as a novel immune checkpoint molecule. We developed a novel anti-LSR antibody (#27-6 mF-18) that defects antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity activity. The #27-6 mF-18 cross-reacts with both human and mouse LSR. We found that LSR was expressed on 4T1 murine breast cancer cell line. The #27-6 mF-18 exhibited antitumor effects against the 4T1 syngeneic tumor model, a poor immunogenic model refractory to treatment with anti-PD-1 or anti-CTLA-4 antibodies. Compared with control antibody-treated mice, mice treated with #27-6 mF-18 showed significantly increased numbers of CD8+ T cells and a ratio of activated CD8+ T cells infiltrated in the tumor tissue. This antitumor effect was abrogated by CD8+ T-cell depletion through anti-CD8 antibody treatment, indicating that LSR negatively regulates tumor immunity by repressing CD8+ T cells. These findings show that LSR negatively regulates T-cell immune activity. LSR targeting could provide immune checkpoint inhibitors for cancer immunotherapy.

Nano-particulate Toll-like Receptor 9 Agonist Potentiates the Antitumor Activity of Anti-Glypican-1 Antibody.

BACKGROUND/AIM: Monoclonal antibodies (mAbs) that target tumor antigens have recently been developed. Their antitumor activity is mainly achieved through antibody-dependent cellular cytotoxicity (ADCC) via effector cells such as tumor-infiltrated macrophages and natural killer (NK) cells. CpG oligodeoxynucleotides (ODNs) have potent antitumor activity and are considered to increase the tumor infiltration of macrophages and NK cells; however, a completely solubilized novel CpG-schizophyllan (SPG) complex, K3-SPG, displays more potent antitumor activity. We recently reported the significant antitumor activity of anti-glypican-1 (GPC1) mAb against GPC1-positive esophageal squamous cell carcinoma (ESCC) via ADCC. The aim of this study was to evaluate the potential synergistic antitumor activity of anti-GPC1 mAb and K3-SPG and elucidate the underlying mechanisms using a xenograft model of GPC1-positive human ESCC cells. MATERIALS AND METHODS: The established human esophageal cancer cell line TE14 was subcutaneously injected into SCID mice. Xenograft mice were treated with anti-GPC1 mAb, K3-SPG, or their combination. Antitumor activity was evaluated by measuring the tumor volume. For FACS analysis, agents were administrated, and tumors were resected 1 day after the final treatment. RESULTS: Anti-GPC1 mAb or K3-SPG monotherapy showed dose-dependent antitumor activity, and combination therapy with anti-GPC1 mAb and K3-SPG showed antitumor activity (p=0.0859). Flow cytometry revealed significantly increased numbers of macrophages (p=0.0133) and of the ratio of activated NK cells/total NK cells (p=0.0058) following K3-SPG or combination therapy. CONCLUSION: Combination therapy with K3-SPG and anti-GPC1 mAb or another antitumor mAb may represent a new cancer treatment option acting via ADCC.

Leucine-rich alpha-2 glycoprotein as a potential biomarker for large vessel vasculitides.

Objectives: Serum levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) have been used as useful biomarkers for reflecting the activity of large vessel vasculitides (LVV). However, a novel biomarker that could have a complementary role to these markers is still required. In this retrospective observational study, we investigated whether leucine-rich α-2 glycoprotein (LRG), a known biomarker in several inflammatory diseases, could be a novel biomarker for LVVs. Methods: 49 eligible patients with Takayasu arteritis (TAK) or giant cell arteritis (GCA) whose serum was preserved in our laboratory were enrolled. The concentrations of LRG were measured with an enzyme-linked immunosorbent assay. The clinical course was reviewed retrospectively from their medical records. The disease activity was determined according to the current consensus definition. Results: The serum LRG levels were higher in patients with active disease than those in remission, and decreased after the treatments. While LRG levels were positively correlated with both CRP and erythrocyte sedimentation rate, LRG exhibited inferior performance as an indicator of disease activity compared to CRP and ESR. Of 35 CRP-negative patients, 11 had positive LRG. Among the 11 patients, two had active disease. Conclusion: This preliminary study indicated that LRG could be a novel biomarker for LVV. Further large studies should be required to promise the significance of LRG in LVV.

Combination of pimitespib (TAS-116) with sunitinib is an effective therapy for imatinib-resistant gastrointestinal stromal tumors.

Despite the effectiveness of imatinib, most gastrointestinal stromal tumors (GISTs) develop resistance to the treatment, mainly due to the reactivation of KIT tyrosine kinase activity. Sunitinib, which inhibits the phosphorylation of KIT and vascular endothelial growth factor (VEGF) receptor, has been established as second-line therapy for GISTs. The recently-developed heat shock protein 90 (HSP90) inhibitor pimitespib (PIM; TAS-116) demonstrated clinical benefits in some clinical trials; however, the effects were limited. The aim of our study was therefore to clarify the effectiveness and mechanism of the combination of PIM with sunitinib for imatinib-resistant GISTs. We evaluated the efficacy and mechanism of the combination of PIM with sunitinib against imatinib-resistant GIST using imatinib-resistant GIST cell lines and murine xenograft models. In vitro analysis demonstrated that PIM and sunitinib combination therapy strongly inhibited growth and induced apoptosis in imatinib-resistant GIST cell lines by inhibiting KIT signaling and decreasing auto-phosphorylated KIT in the Golgi apparatus. In addition, PIM and sunitinib combination therapy enhanced antitumor responses in the murine xenograft models compared to individual therapies. Further analysis of the xenograft models showed that the combination therapy not only downregulated the KIT signaling pathway but also decreased the tumor microvessel density. Furthermore, we found that PIM suppressed VEGF expression in GIST cells by suppressing protein kinase D2 and hypoxia-inducible factor-1 alpha, which are both HSP90 client proteins. In conclusion, the combination of PIM and sunitinib is effective against imatinib-resistant GIST via the downregulation of KIT signaling and angiogenic signaling pathways.

Lipolysis-stimulated lipoprotein receptor-targeted antibody-drug conjugate demonstrates potent antitumor activity against epithelial ovarian cancer.

BACKGROUND: Epithelial ovarian cancer (EOC) is a lethal malignant tumor, for which new treatment options are urgently required. Lipolysis-stimulated lipoprotein receptor (LSR) is widely expressed in EOC, and it is associated with poor prognosis. In this study, we developed an antibody-drug conjugate (ADC) targeting LSR as a new therapeutic approach to EOC. METHODS: We, herein, developed novel anti-LSR monoclonal antibodies (mAbs) and an LSR-ADC by conjugating monomethyl auristatin E as a payload. We subsequently evaluated the in vitro and in vivo (on xenograft models) antitumor effect of the LSR-ADC. RESULTS: An overexpression of LSR was observed not only in the primary EOC tumor but also in its lymph node and omental metastases. The EOC cell lines NOVC7-C and OVCAR3 strongly expressed LSR (as compared to ES2 cells). Both the anti-LSR mAb and the LSR-ADC were able to specifically bind to LSR-positive cells and were rapidly internalized and trafficked to the lysosomes. The LSR-ADC demonstrated a potent antitumor effect against NOVC-7C and OVCAR3, but little activity against ES2 cells. In vitro, the LSR-ADC exhibited a potent antitumor effect against NOVC-7C and OVCAR3. Moreover, in the OVCAR3 xenograft models as well as in the patient-derived xenograft models of LSR-positive EOC, the LSR-ADC significantly inhibited tumor growth. The LSR-ADC also suppressed the omental/bowel metastases in OVCAR3-Luc xenografts and improved the median survival. CONCLUSION: The developed LSR-ADC demonstrated a significant antitumor activity against LSR-positive EOC cell lines and tumors. Our preclinical data support the use of the LSR-ADC as a novel therapy for patients with LSR-positive ovarian cancer.

Lung CCR6-CXCR3- type 2 helper T cells as an indicator of progressive fibrosing interstitial lung diseases.

Progressive fibrosing interstitial lung diseases (PF-ILDs) have a poor prognosis and may be resistant to corticosteroids and/or immunosuppressants, but antifibrotic therapies such as nintedanib and pirfenidone have been shown to slow the deterioration of lung function. The aim of this study was to identify the characteristic cellular profile of bronchoalveolar lavage fluid at diagnostic bronchoscopy for predicting PF-ILDs, defined as fibrotic diseases on chest high-resolution computed tomography with more than a 5% relative decline in the percent predicted value of forced vital capacity (FVC) over 6 months. The proportions of inflammatory cells, CCR6-CXCR3- T helper type 2 (Th2) cells among conventional CD4+ T cells in bronchoalveolar lavage fluid (BALF) and peripheral blood, were measured by flowcytometry. The proportion of lymphocytes in BALF was significantly higher in non-PF-ILD patients than in PF-ILD patients. The proportion of Th2 cells in BALF, but not in peripheral blood, was significantly higher in PF-ILD patients than in non-PF-ILD patients. Multivariate analysis showed that a greater population of Th2 cells in BALF was the only indicator for PF-ILDs. An increased proportion of Th2 cells in BALF is associated with greater deterioration of lung function in fibrotic interstitial lung diseases.

SOCS1 Gene Therapy for Head and Neck Cancers: An Experimental Study.

BACKGROUND/AIM: Head and neck squamous cell carcinoma (HNSCC) is a fatal and debilitating disease, which is characterized by steady, poor survival rates despite advances in treatment. Suppressor of cytokine signaling (SOCS) 1 is up-regulated following cytokine-induced Janus kinase - signal transducer and activator of transcription (JAK-STAT) pathway activation, and inhibitors of cytokine signaling play roles in regulating cell growth and differentiation. We investigated the therapeutic potential of SOCS1 for HNSCC. MATERIALS AND METHODS: We used cell lines of oropharyngeal and tongue cancers (Detroit-562 and SCC-9, respectively) and a recombinant adenovirus vector expressing SOCS1 (AdSOCS1). RESULTS: AdSOCS1-induced SOCS1 overexpression significantly decreased cell proliferation through G2M phase cell cycle arrest and apoptosis. AdSOCS1 inhibited cell growth more strongly in SCC-9 cells than in Detroit-562 cells. JAK inhibitor I induced cell cycle arrest at the G0/G1 and GfM phases in Detroit-562 and SCC-9 cells, respectively. AdSOCS1 also decreased the activity of phosph-STAT3 (pSTAT3) and phosphop44/42 mitogen-activated protein kinase (p-p44/42 MAPK), as well as the expression of the anti-apoptotic protein B-cell lymphoma-extra large (Bcl-xL). JAK inhibitor I decreased the expression of pSTAT3, but not p-p44/42 or Bcl-xL. The MAPK/extracellular signal-regulated kinase (MEK) inhibitor, U0126, decreased the expression of Bcl-xL in SCC-9 cells, but not in Detroit-562 cells. AdSOCS1 treatment inhibited tumor growth in mouse xenograft models. CONCLUSION: Overexpression of SOCS1 has a potent antitumor effect on HNSCC, suggesting the potential for clinical use. The varying effectiveness among cancer cells by over expression of SOCS1 may contribute to efficacy of SOCS 1 gene therapy for clinical use.

Gene therapy with SOCS1 induces potent preclinical antitumor activities in oral squamous cell carcinoma.

BACKGROUND: Constitutive activation of STAT3 promotes oncogenesis and growth of oral squamous cell carcinoma (OSCC). We investigated the mechanism of action of suppressor of cytokine signaling 1 (SOCS1), an endogenous inhibitor of JAK, as gene therapy for OSCC. METHODS: Antitumor effect of SOCS1 was compared to JAK inhibitor I by cell proliferation assay, cell cycle analysis, and apoptosis analysis in vitro. In addition, antitumor effect was evaluated using xenograft mouse models in vivo. RESULTS: JAK inhibitor I inhibited the proliferation of KOSC2 cl3-43 or T3M-1 clone2 OSCC cell lines in vitro. While JAK inhibitor I arrested both cell lines at the G2/M phase, induction of apoptosis was observed in T3M-1 clone2 cells, but not KOSC2-cl3-43 cells. An adenoviral vector expressing SOCS1 (AdSOCS1) significantly decreased the proliferation of both OSCC cell lines and induced G2/M phase cell cycle arrest and apoptosis, suggesting that induction of apoptosis of KOSC2 cl3-43 cells by AdSOCS1 is regulated by the JAK/STAT independent pathway. Overexpression of SOCS1 inhibited activation of the JAK/STAT and p44/42 MAPK pathways, while JAK inhibitor I inhibited activation of the JAK/STAT pathway only. Consistently, expression of Mcl-1 was decreased by overexpression of SOCS1, but not JAK inhibitor I. Additionally, KOSC2 cl3-43 or T3M-1 clone2 OSCC cells were subcutaneously implanted in the flanks of two xenograft mouse models. As compared to a control adenovirus vector (AdLacZ), intratumor injection of AdSOCS1 significantly decreased the tumor volume and induced apoptosis in vivo. CONCLUSION: SOCS1 gene therapy may be a beneficial approach for the treatment of OSCC.

Targeted therapy for drug-tolerant persister cells after imatinib treatment for gastrointestinal stromal tumours.

BACKGROUND: Despite the effectiveness of tyrosine kinase inhibitors (TKI), gastrointestinal stromal tumours (GIST) develop after the withdrawal of TKI. Based on previous studies, a subpopulation of drug-tolerant cells called "persister cells" may be responsible for the recurrence and have thus, gained attention as a novel target in cancer therapy. METHODS: The metabolic changes were investigated in imatinib-derived persister GIST cells. We investigated the efficacy and the mechanism of GPX4 inhibitor, which is known as a major inducer of "ferroptosis". We also evaluated the effects of RSL3 to the gefitinib-derived persister lung cancer cells. RESULTS: We demonstrated a downregulation of glucose metabolism, subsequent decrease in the glutathione level and sensitivity to glutathione peroxidase 4 (GPX4) inhibitor, RSL3 in persister cells. As the cell death induced by RSL3 was found to be "iron-dependent" and "caspase-independent", loss of GPX4 function could have possibly induced selective persister cell ferroptotic death. In the xenograft model, we confirmed the inhibition of tumour regrowth after discontinuation of imatinib treatment. Moreover, RSL3 prevented the growth of gefitinib-derived persister lung cancer cells. CONCLUSIONS: RSL3 combined with TKI may be a promising therapy for both GIST and epidermal growth factor receptor-mutated lung cancer.

Correction: Lipolysis-stimulated lipoprotein receptor overexpression is a novel predictor of poor clinical prognosis and a potential therapeutic target in gastric cancer.

[This corrects the article DOI: 10.18632/oncotarget.25952.].

Glypican-1 Is a Novel Target for Stroma and Tumor Cell Dual-Targeting Antibody-Drug Conjugates in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a stroma-rich cancer. Extracellular matrix proteins produced by cancer-associated fibroblasts (CAFs) found in tumor stroma that impedes effective delivery of chemotherapeutic agents results in poor response in patients with PDAC. Previously, our group reported that glypican-1 (GPC1) was overexpressed in human PDAC and negatively correlated with patient survival. Immunohistochemical analysis of 25 patients with PDAC tumor specimens revealed elevated expression of GPC1 in stromal cells and pancreatic cancer cells in 80% of patients. Interestingly, GPC1 was expressed on CAFs in PDAC. We generated a GPC1 antibody-drug conjugate conjugated with monomethyl auristatin E [GPC1-ADC(MMAE)] and evaluated its preclinical antitumor activity by targeting GPC1-positive CAF and cancer cells in PDAC. GPC1-ADC(MMAE) inhibited the growth of GPC1-positive PDAC cell lines in vitro Furthermore, GPC1-ADC(MMAE) showed a potent antitumor effect in the PDAC patient-derived tumor xenograft (PDX) model against GPC1-positive CAF and heterogeneous GPC1-expressing cancer cells. Notably, GPC1-ADC(MMAE) showed robust preclinical efficacy against GPC1 in a stroma-positive/cancer-negative PDAC PDX model. GPC1-ADC(MMAE) was delivered and internalized to CAFs. Although apoptosis was not observed in CAFs, the released MMAE from CAFs via MDR-1 induced apoptosis of cancer cells neighboring CAFs and efficiently inhibited PDAC tumor growth. GPC1-ADC(MMAE) exhibited potent and unique antitumor activity in GPC1-positive PDAC PDX models, which suggests that GPC1 is a novel therapeutic target in PDAC and other stromal GPC1-positive solid tumors. These findings show that targeting GPC1 on CAF using GPC1-ADC(MMAE) is a useful approach in case of stroma-rich tumors such as PDAC.

Anti-Glypican-1 Antibody-drug Conjugate as Potential Therapy Against Tumor Cells and Tumor Vasculature for Glypican-1-Positive Cholangiocarcinoma.

Cholangiocarcinoma is a highly malignant cancer. Many patients need systemic chemotherapy to prevent tumor development and recurrence; however, their prognosis is poor due to the lack of effective therapy. Therefore, a new treatment option is urgently required. We recently identified glypican-1 (GPC1) as a novel cancer antigen of esophageal squamous cell carcinoma. We also demonstrated the efficacy and safety of GPC1-targeted ADC (GPC1-ADC) conjugating anti-GPC1 mAb possessing high internalization activity with monomethyl auristatin F (MMAF), which is a potent tubulin polymerizing inhibitor. In this study, we confirmed that GPC1 was highly expressed in cholangiocarcinoma cells and tissues. IHC analysis of 49 extrahepatic cholangiocarcinoma patient tumor specimens revealed high expression of GPC1 in 47% of patients. These patients demonstrated significantly poorer prognosis compared with the low-expression group in terms of disease-free survival and overall survival (P < 0.05). GPC1 was also expressed in tumor vessels of cholangiocarcinoma, but not on the vessels of nontumor tissues. MMAF-conjugated GPC1-ADC showed potent tumor growth inhibition against GPC1-positive cholangiocarcinoma cells in vitro and in vivo In a GPC1 knockout xenograft model, GPC1-ADC partially inhibited tumor growth. Vascular endothelial cells in tumor tissues of GPC1-negative xenograft mice expressed GPC1 and were arrested in the G2-M phase of cell cycle by GPC1-ADC. GPC1-ADC exhibits direct as well as indirect antitumor effects via inhibition of tumor angiogenesis. Our preclinical data highlight GPC1-ADC as a promising therapy for GPC1-positive cholangiocarcinoma.

A glypican-1-targeted antibody-drug conjugate exhibits potent tumor growth inhibition in glypican-1-positive pancreatic cancer and esophageal squamous cell carcinoma.

An antibody-drug conjugate (ADC) is a promising therapeutic modality because selective and effective delivery of an anti-cancer drug is achieved by drug-conjugated antibody-targeting cancer antigen. Glypican 1 (GPC1) is highly expressed in malignant tumors, including pancreatic ductal adenocarcinoma (PDAC) and esophageal squamous cell carcinoma (ESCC). Herein, we describe the usefulness of GPC1-targeting ADC. Humanized anti-GPC1 antibody (clone T2) was developed and conjugated with monomethyl auristatin E (MMAE) via maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl (mc-vc-PABC) linkers (humanized GPC1-ADC[MMAE]). Humanized GPC1-ADC(MMAE) inhibited the growth of GPC1-positive PDAC and ESCC cell lines via inducing cycle arrest in the G2/M phase and apoptosis in vitro. The binding activity of humanized GPC1-ADC(MMAE) with GPC1 was comparable with that of the unconjugated anti-GPC1 antibody. The humanized GPC1-ADC(MMAE) was effective in GPC1-positive BxPC-3 subcutaneously xenografted mice but not in GPC1-negative BxPC-3-GPC1-KO xenografted mice. To assess the bystander killing activity of the humanized GPC1-ADC(MMAE), a mixture of GPC1-positive BxPC-3 and GPC1-negative BxPC-3-GPC1-KO-Luc cells were subcutaneously inoculated, and a heterogenous GPC1-expressing tumor model was developed. The humanized GPC1-ADC(MMAE) inhibited the tumor growth and decreased the luciferase signal, measured with an in vivo imaging system (IVIS), which suggests that the suppression of the BxPC-3-GPC1-KO-Luc population. The humanized GPC1-ADC(MMAE) also inhibited the established liver metastases of BxPC-3 cells and significantly improved the overall survival of the mice. It exhibited a potent antitumor effect on the GPC1-positive PDAC and ESCC patient-derived xenograft (PDX) models. Our preclinical data demonstrate that GPC1 is a promising therapeutic target for ADC.

Propranolol suppresses gastric cancer cell growth by regulating proliferation and apoptosis.

BACKGROUND: Despite improvements in gastric cancer treatment, the mortality associated with advanced gastric cancer is still high. The activation of ß-adrenergic receptors by stress has been shown to accelerate the progression of several cancers. Accordingly, increasing evidence suggests that the blockade of ß-adrenergic signaling can inhibit tumor growth. However, the effect of ß-blockers, which target several signaling pathways, on gastric cancer remains to be elucidated. This study aimed to investigate the anti-tumor effects of propranolol, a non-selective ß-blocker, on gastric cancer. METHODS: We explored the effect of propranolol on the MKN45 and NUGC3 gastric cancer cell lines. Its efficacy and the mechanism by which it exerts anti-tumor effects were examined using several assays (e.g., cell proliferation, cell cycle, apoptosis, and wound healing) and a xenograft mouse model. RESULTS: We found that propranolol inhibited tumor growth and induced G1-phase cell cycle arrest and apoptosis in both cell lines. Propranolol also decreased the expression of phosphorylated CREB-ATF and MEK-ERK pathways; suppressed the expression of matrix metalloproteinase-2, 9 and vascular endothelial growth factor; and inhibited gastric cancer cell migration. In the xenograft mouse model, propranolol treatment significantly inhibited tumor growth, and immunohistochemistry revealed that propranolol led to the suppression of proliferation and induction of apoptosis. CONCLUSIONS: Propranolol inhibits the proliferation of gastric cancer cells by inducing G1-phase cell cycle arrest and apoptosis. These findings indicate that propranolol might have an opportunity as a new drug for gastric cancer.

The Skin-Liver Axis Modulates the Psoriasiform Phenotype and Involves Leucine-Rich α-2 Glycoprotein.

Leucine-rich α-2 glycoprotein (LRG), one of the acute phase proteins mainly produced by the liver, similar to C-reactive protein, has been recognized as an inflammatory biomarker for rheumatoid arthritis and inflammatory bowel diseases. We recently demonstrated that LRG was also increased in the sera of psoriasis patients and correlated well with disease activity with a sensitivity and specificity much higher than C-reactive protein; however, whether LRG mechanistically contributed to the pathogenesis of psoriasis remained unclear. In this study, we explored the role of LRG in psoriasiform inflammation using LRG-knockout (KO) mice in an imiquimod (IMQ)-mediated model. Following topical treatment with IMQ, serum levels of LRG and its expression in the liver were abruptly elevated. Similarly, an acute surge of proinflammatory cytokines was observed in the liver, including IL-1ß, TNF-α, and IL-6, although LRG-KO mice showed delayed responses. LRG-KO mice showed less skin inflammation in the IMQ model than wild-type mice. K5.Stat3C mice developed psoriasis-like lesions following tape stripping, which also abruptly induced LRG expression in the liver. A deficiency of Lrg mitigated tape stripping-induced lesions, similar to the IMQ model. These results indicate that LRG modulates both feed-forward and feedback loops of cytokines in the skin-liver axis involved with psoriasiform inflammation.

The involvement of leucine-rich α-2 glycoprotein in the progression of skin and lung fibrosis in bleomycin-induced systemic sclerosis model.

OBJECTIVE: Systemc sclerosis (SSc) is an autoimmune disorder characterized by fibrosis of the skin and internal organs. Recently, it has been shown that leucine-rich α-2 glycoprotein (LRG) functions as a modulator of transforming growth factor-ß (TGF-ß) signaling in fibrosis. We aimed to characterize the effect of LRG in SSc model and SSc patients. METHODS: Histological analysis was performed on LRG knockout (KO) and wild type (WT) mouse in the skin and the lung after bleomycin administration. Serum LRG levels were measured during the injection period. Gene expression analysis of the skin and lung tissue from LRG KO and WT mice was performed. In addition, serum LRG levels were determined in SSc patients and healthy controls. RESULTS: LRG KO mice display an inhibition of fibrosis in the skin in association with a decrease of dermal thickness, collagen deposition, and phospho-Smad3 expression after bleomycin. Serum LRG concentration significantly increased in WT mice after bleomycin. There was also a suppression of inflammation and fibrosis in the LRG KO mouse lung indicated by a reduction of lung weight, collagen content, and phospho-Smad3 expression after bleomycin. Gene expressions of TGF-ß and Smad2/3 were significantly reduced in LRG KO mice. Serum LRG levels in SSc patients were significantly higher than those in controls. CONCLUSION: LRG promotes fibrotic processes in SSc model through TGF-ß-Smad3 signaling, and LRG can be a biomarker for SSc in humans and also a potential therapeutic target for SSc.

LSR promotes epithelial ovarian cancer cell survival under energy stress through the LKB1-AMPK pathway.

Lipolysis-stimulated lipoprotein receptor (LSR), also known as a component of tricellular tight junctions, is highly expressing in epithelial ovarian cancer (EOC). However, the biological role of LSR in EOC cells remains unclear. In this study, we evaluated liver kinase B1 (LKB1) mediated AMP-activated protein kinase (AMPK) activity and investigated the effect of LSR on EOC cell survival under energy stress. LSR increased the levels of phospho-AMPKα at Thr172 and phospho-acetyl-CoA carboxylase (ACC) at Ser79 via LKB1-AMPK pathway in glucose deprivation in vitro. The increase of P-AMPKα (Thr172) and P-ACC (Ser79) was also detected in tumor microenvironment in vivo. Meanwhile, LSR promoted LKB1 localization at the cell membrane of EOC cells. By cell survival analysis, LSR attenuated glucose deprivation-induced cell death in EOC cells in vitro. Our results suggest that LSR promotes EOC cell survival and tumor growth through the LKB1-AMPK pathway.

Evaluation of leucine-rich alpha-2 glycoprotein as a biomarker of fetal infection.

This study aimed to determine the association between umbilical cord leucine-rich alpha-2 glycoprotein (LRG) and fetal infection and investigate the underlying mechanism of LRG elevation in fetuses. We retrospectively reviewed the medical records of patients who delivered at Osaka University Hospital between 2012 and 2017 and selected those with histologically confirmed chorioamnionitis (CAM), which is a common pregnancy complication that may cause neonatal infection. The participants were divided into two groups: CAM with fetal infection (CAM-f[+] group, n = 14) and CAM without fetal infection (CAM-f[-] group, n = 31). Fetal infection was defined by the histological evidence of funisitis. We also selected 50 cases without clinical signs of CAM to serve as the control. LRG concentrations in sera obtained from the umbilical cord were unaffected by gestational age at delivery, neonatal birth weight, nor the presence of noninfectious obstetric complications (all, p > 0.05). Meanwhile, the LRG levels (median, Interquartile range [IQR]) were significantly higher in the CAM-f(+) group (10.37 [5.21-13.7] µg/ml) than in the CAM-f(-) (3.61 [2.71-4.65] µg/ml) or control group (3.39 [2.81-3.93] µg/ml; p < 0.01). The area under the receiver operating characteristic (ROC) curve of LRG for recognizing fetal infection was 0.92 (optimal cutoff, 5.08 µg/ml; sensitivity, 86%; specificity, 88%). In a mouse CAM model established by lipopolysaccharide administration, the fetal LRG protein in sera and LRG mRNA in the liver were significantly higher than those in phosphate-buffered saline (PBS)-administered control mice (p < 0.01). In vitro experiments using a fetal liver-derived cell line (WRL68) showed that the expression of LRG mRNA was significantly increased after interleukin (IL)-6, IL-1ß, and tumor necrosis factor- alpha (TNF-α) stimulation (p < 0.01); the induction was considerably stronger following IL-6 and TNF-α stimulation (p < 0.01). In conclusion, LRG is an effective biomarker of fetal infection, and fetal hepatocytes stimulated with inflammatory cytokines may be the primary source of LRG production in utero.

Correlation of increased serum leucine-rich α2-glycoprotein levels with disease prognosis, progression, and activity of interstitial pneumonia in patients with dermatomyositis: A retrospective study.

OBJECTIVE: To investigate whether leucine-rich α2-glycoprotein (LRG) can be a biomarker for the disease activity, progression, and prognosis of interstitial pneumonia (IP) in patients with dermatomyositis (DM). METHODS: Correlations between the clinical findings and serum LRG levels were investigated in 46 patients with DM-IP (33 with acute/subacute IP [A/SIP] and 13 patients with chronic IP [CIP], including 10 fatal cases of IP). RESULTS: The median serum LRG level of 18.4 (14.6-25.2) µg/mL in DM-IP patients was higher than that in healthy control subjects. The median levels of serum LRG at baseline and at 2 and 4 weeks after the initiation of treatment in the patients who died were significantly higher than those in the surviving patients (P = 0.026, 0.029, and 0.008, respectively). The median level of serum LRG in the DM-A/SIP patients was significantly higher than that in the DM-CIP patients (P = 0.0004), and that in the anti-MDA5-Ab-positive group was slightly higher than that in the anti-ARS-Ab-positive group. The serum LRG levels correlated significantly with the serum levels of LDH, C-reactive protein, ferritin, AaDO2, %DLco, and total ground-glass opacity score. The survival rate after 24 weeks in patients with an initial LRG level ≥ 17.6 µg/mL (survival rate: 40%) was significantly lower than that in patients with an initial LRG level < 17.6 µg/mL (100%) (P = 0.0009). CONCLUSION: The serum LRG level may be a promising marker of disease activity, progression, and prognosis in patients with DM-IP.