ERAP2 is a novel target involved in autophagy and activation of pancreatic stellate cells via UPR signaling pathway.

BACKGROUND/OBJECTIVES: Pancreatic ductal adenocarcinoma (PDAC) is characterized by excessive desmoplasia and autophagy-dependent tumorigenic growth. Pancreatic stellate cells (PSCs) as a predominant stromal cell type play a critical role in PDAC biology. We have previously reported that autophagy facilitates PSC activation, however, the mechanism remains unknown. We investigated the mechanism of autophagy in PSC activation. METHODS: We compared gene expression profiles between patient-derived PSCs from pancreatic cancer and chronic pancreatitis using a microarray. The stromal expression of target gene in specimen of PDAC patients (n = 63) was analyzed. The effect of target gene on autophagy and activation of PSCs was investigated by small interfering RNAs transfection, and the relationship between autophagy and ER stress was investigated. We analyzed the growth and fibrosis of xenografted tumor by orthotopic models. RESULTS: In analysis of gene expression microarray, endoplasmic reticulum aminopeptidase 2 (ERAP2) upregulated in cancer-associated PSCs was identified as the target gene. High stromal ERAP2 expression is associated with a poor prognosis of PDAC patients. Knockdown of ERAP2 inhibited unfolded protein response mediated autophagy, and led to inactivation of PSCs, thereby attenuating tumor-stromal interactions by inhibiting production of IL-6 and fibronectin. In vivo, the promoting effect of PSCs on xenografted tumor growth and fibrosis was inhibited by ERAP2 knockdown. CONCLUSIONS: Our findings demonstrate a novel mechanism of PSCs activation regulated by autophagy. ERAP2 as a promising therapeutic target may provide a novel strategy for the treatment of PDAC.

Contribution of pre-existing neoantigen-specific T cells to a durable complete response after tumor-pulsed dendritic cell vaccine plus nivolumab therapy in a patient with metastatic salivary duct carcinoma.

Although immune checkpoint inhibitors (ICIs) have emerged as new therapeutic options for refractory cancer, they are only effective in select patients. Tumor antigen-pulsed dendritic cell (DC) vaccine therapy activates tumor-specific cytotoxic T lymphocytes, making it an important immunotherapeutic strategy. Salivary ductal carcinoma (SDC) carries a poor prognosis, including poor long-term survival after metastasis or recurrence. In this study, we reported a case of refractory metastatic SDC that was treated with a tumor lysate-pulsed DC vaccine followed by a single injection of low-dose nivolumab, and a durable complete response was achieved. We retrospectively analyzed the immunological factors that contributed to these long-lasting clinical effects. First, we performed neoantigen analysis using resected metastatic tumor specimens obtained before treatment. We found that the tumor had 256 non-synonymous mutations and 669 class I high-affinity binding neoantigen peptides. Using synthetic neoantigen peptides and ELISpot analysis, we found that peripheral blood mononuclear leukocytes cryopreserved before treatment contained pre-existing neoantigen-specific T cells, and the cells obtained after treatment exhibited greater reactivity to neoantigens than those obtained before treatment. Our results collectively suggest that the rapid and long-lasting effect of this combination therapy in our patient may have resulted from the presence of pre-existing neoantigen-specific T cells and stimulation and expansion of those cells following tumor lysate-pulsed DC vaccine and ICI therapy.

Intranodal Administration of Neoantigen Peptide-loaded Dendritic Cell Vaccine Elicits Epitope-specific T Cell Responses and Clinical Effects in a Patient with Chemorefractory Ovarian Cancer with Malignant Ascites.

Chemorefractory ovarian cancer has limited therapeutic options. Hence, new types of treatment including neoantigen-specific immunotherapy need to be investigated. Neoantigens represent promising targets for personalized cancer immunotherapy. We here describe the clinical and immunological effects of a neoantigen peptide-loaded DC-based immunotherapy in a patient with recurrent and chemoresistant ovarian cancer. A 71-year-old female patient with chemorefractory ovarian cancer and malignant ascites received intranodal vaccination of DCs loaded with four neoantigen peptides that were predicted by our immunogenomic pipeline. Following four rounds of vaccinations with this therapy, CA-125 levels were remarkably declined and tumor cells in the ascites were also decreased. Concordantly, the tumor-related symptoms such as respiratory discomfort improved without any adverse reactions. The reactivity against one HLA-A2402-restricted neoantigen peptide derived from a mutated PPM1 F protein was detected in lymphocytes from peripheral blood by IFN-γ ELISPOT assay. Furthermore, the neoantigen (PPM1 F mutant)-specific TCRs were detected in the tumor-infiltrating T lymphocytes post-vaccination. Our results showed that vaccination with intranodal injection of neoantigen peptide-loaded DCs may have clinical and immunological impacts on cancer treatment.

NFκB and TGFß contribute to the expression of PTPN3 in activated human lymphocytes.

We previously reported that protein tyrosine phosphatase non-receptor type 3 (PTPN3), which is upregulated in activated lymphocytes, acts as an immune checkpoint. However, the mechanism by which PTPN3 expression is enhanced in activated lymphocytes is unknown. In this study, we analyzed the mechanism of PTPN3 expression in activated lymphocytes with a view for developing a novel immune checkpoint inhibitor that suppresses PTPN3. Through the activation process, lymphocytes showed enhanced NFκB activation as well as increased PTPN3 expression. NFκB enhanced proliferation, migration, and cytotoxicity of lymphocytes. Furthermore, NFκB enhanced PTPN3 expression and tyrosine kinase activation. TGFß reduced PTPN3 expression and NFκB activation in the cancer microenvironment, and suppressed the biological activity of lymphocytes. The results of this study are expected to provide significant implications for improving existing immunotherapy and developing novel immunotherapy.

PTPN3 expressed in activated T lymphocytes is a candidate for a non-antibody-type immune checkpoint inhibitor.

It has been shown that protein tyrosine phosphatase non-receptor type (PTPN) 3 inhibits T-cell activation. However, there is no definitive conclusion about how the inhibition of PTPN3 in lymphocytes affects immune functions in human lymphocytes. In the present study, we showed that PTPN3 inhibition significantly contributes to the enhanced activation of activated human lymphocytes. The PTPN3 expression of lymphocytes was significantly increased through the activation process using IL-2 and anti-CD3 mAb. Interestingly, inhibiting the PTPN3 expression in activated lymphocytes significantly augmented the proliferation, migration, and cytotoxicity through the phosphorylation of zeta-chain-associated protein kinase 70 (ZAP-70), lymphocyte-specific protein tyrosine kinase (LCK), and extracellular signal-regulated kinases (ERK). Lymphocyte activation by PTPN3 inhibition was observed only in activated CD3+ T cells and not in NK cells or resting T cells. In therapy experiments using autologous tumors and lymphocytes, PTPN3 inhibition significantly augmented the number of tumor-infiltrated lymphocytes and the cytotoxicity of activated lymphocytes. Our results strongly imply that PTPN3 acts as an immune checkpoint in activated lymphocytes and that PTPN3 inhibitor may be a new non-antibody-type immune checkpoint inhibitor for cancer therapy.

Pancreatic Juice Exosomal MicroRNAs as Biomarkers for Detection of Pancreatic Ductal Adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a lethal neoplasm because of difficulties in early detection. Several studies have recently suggested that exosomes may have potential as novel biomarkers. This study aimed to isolate exosomes from pancreatic juice and to investigate whether exosomal microRNAs (ex-miRs) could be used as biomarkers for PDAC. METHODS: Pancreatic juice was collected from patients with PDAC and chronic pancreatitis (CP) by endoscopic retrograde pancreatography. Exosomes were extracted by ultracentrifugation. The presence of exosomes was confirmed by electron microscopy and Western blotting using anti-CD63, -CD81, and -TSG101 antibodies. Relative levels of ex-miR-21 and ex-miR-155 were quantified and compared between PDAC and CP patients. RESULTS: A total of 35 pancreatic juice samples (27 PDAC and 8 CP) were collected. Relative levels of both ex-miR-21 and ex-miR-155 were significantly higher in PDAC patients compared with CP patients (p < 0.001 and p = 0.008, respectively). By contrast, no significant difference was apparent in relative levels of miR-21 and miR-155 in whole pancreatic juice from PDAC patients compared with CP patients (p = 0.08 and p = 0.61, respectively). Ex-miR-21 and ex-miR-155 levels discriminated PDAC patients from CP patients with area under the curve values of 0.90 and 0.89, respectively. The accuracies of ex-miR-21 levels, ex-miR-155 levels, and pancreatic juice cytology were 83%, 89%, and 74%, respectively. When combining the results of ex-miR profiling with pancreatic juice cytology, the accuracy was improved to 91%. CONCLUSIONS: We successfully extracted exosomes from pancreatic juice. Ex-miRs, including ex-miR-21 and ex-miR-155, in pancreatic juice may be developed as biomarkers for PDAC.

Brain-derived neurotrophic factor/tropomyosin-related kinase B signaling pathway contributes to the aggressive behavior of lung squamous cell carcinoma.

The tropomyosin-related kinase (Trk) family consists of TrkA, TrkB, and TrkC, which play essential roles in tumor progression and/or suppression in various cancers. Little is known about the biological significance of the Trk family in human lung squamous cell carcinoma (SCC). Here we investigated the clinical significance of the protein expression of Trk family members in samples from 99 SCC patients, and we explored the relationship between invasion/proliferation activities and Trk expression using lung SCC cell lines to clarify the biological significance of the Trk family in lung SCC. Immunohistochemical high expression of TrkB was significantly correlated with vascular invasion (P=0.004), lymph node metastasis (P<0.001), and advanced stage (P=0.0015). The overall survival of the patients with TrkB-high expression was significantly shorter than those with TrkB-low expression (P=0.0110). TrkA/TrkC expressions were not predictors of poor prognosis. An in vitro assay demonstrated that the inhibition of brain-derived neurotrophic factor (BDNF) (a TrkB ligand) and TrkB by K252a (a Trk inhibitor) or siRNA (BDNF-siRNA, TrkB-siRNA) suppressed the invasion, migration, and proliferative activities of lung SCC cells. The administration of recombinant human BDNF (rhBDNF) enhanced the invasion, migration, and proliferation activities, which were abrogated by K252a. TrkB-siRNA transfection increased the protein expression of E-cadherin and decreased vimentin expressions in lung SCC cells. Matrix metalloproteinase-2 (MMP-2)-mediated gelatin degradations were decreased in lung SCC cells transfected with TrkB-siRNA. Thus, TrkB-high expression is an indicator of poor prognosis in lung SCC, probably due to invasion/proliferation activities promoted by the BDNF/TrkB signaling pathway, which could become a therapeutic target for lung SCC.

[Development of Holistic Cancer Treatment Centering Cancer Patients - From the Standpoint of Hypoxia and Hedgehog Signaling].

Recently, hypoxia that is one of cancer microenvironments, takes much attention. Because circumstance that we usually perform experiment is 20% O2 condition, it is likely that different signaling pathways may be activated in vivo cancer. We focused Hedgehog(Hh)signaling as one of activated pathways under hypoxia. It has been shown that Hh signaling is activated under hypoxia, followed by inducing malignant phenotypes in pancreatic cancer. Therefore, Hh signaling inhibitor should elicit anti-tumor effect. However, if we consider "whole-person therapy" we should confirm how Hh signaling affects the function of immune cells. In the present study, we describe hypoxia/Hh signaling/functions of cancer cells and immune cells focusing our previous results.

Nuclear expression of Y-box binding protein-1 is associated with poor prognosis in patients with pancreatic cancer and its knockdown inhibits tumor growth and metastasis in mice tumor models.

The objective of this study was to examine the implication of Y-box-binding protein-1 (YB-1) for the aggressive phenotypes, prognosis and therapeutic target in pancreatic ductal adenocarcinoma (PDAC). YB-1 expression in PDAC, pancreatic intraepithelial neoplasia (PanIN) and normal pancreas specimens was evaluated by immunohistochemistry, and its correlation with clinicopathological features was assessed in patients with PDAC. The effects of YB-1 on proliferation, invasion and expressions of cell cycle-related proteins and matrix metalloproteinases (MMPs) were analyzed by WST-8, cell cycle and Matrigel invasion assays, Western blotting and quantitative RT-PCR in PDAC cells transfected with YB-1-siRNAs. To verify the significance of YB-1 for tumor progression in vivo, the growth and metastasis were monitored after intrasplenic implantation of ex vivo YB-1 siRNA-transfected PDAC cells, and YB-1-targeting antisense oligonucleotides were intravenously administered in nude mice harboring subcutaneous tumor. The intensity of YB-1 expression and positivity of nuclear YB-1 expression were higher in PDAC than PanIN and normal pancreatic tissues. Nuclear YB-1 expression was significantly associated with dedifferentiation, lymphatic/venous invasion and unfavorable prognosis. YB-1 knockdown inhibited cell proliferation via cell cycle arrest by S-phase kinase-associated protein 2 downregulation and consequent p27 accumulation, and decreased the invasion due to downregulated membranous-type 2 MMP expression in PDAC cells. Tumor growth and liver metastasis formation were significantly suppressed in nude mice after implantation of YB-1-silenced PDAC cells, and the YB-1 targeting antisense oligonucleotide significantly inhibited the growth of subcutaneous tumors. In conclusion, YB-1 may be involved in aggressive natures of PDAC and a promising therapeutic target.

Hedgehog signaling regulates PDL-1 expression in cancer cells to induce anti-tumor activity by activated lymphocytes.

We investigated whether hypoxia-induced activation of Hh signaling contributes to PDL-1 expression in cancer and whether it affects the anti-tumor function of activated lymphocytes. Hypoxia augmented PDL-1 expression and inhibition of Hh signaling reduced PDL-1 expression under hypoxia. When activated lymphocytes were cocultured with cancers treated with a Hh inhibitor, activated lymphocyte cell numbers increased under hypoxia. In contrast, this increase was abrogated when cancer cells were treated with a PDL-1 neutralizing antibody. These results suggest that Hh signaling is one of regulatory pathways of PDL-1 expression under hypoxia and that inhibiting Hh signaling may induce lymphocyte anti-tumor activity.

Reoxygenation from chronic hypoxia promotes metastatic processes in pancreatic cancer through the Hedgehog signaling.

Pancreatic ductal adenocarcinoma (PDAC) is among the most deadly types of malignancies because of its high ability to metastasize. PDAC is thought to be under hypoxic condition. Therefore, to investigate the mechanism of metastatic processes, chronic-hypoxia-resistant PDAC cells were newly generated under hypoxic condition for 3-6 months and reoxygenation experiments were performed using these chronic-hypoxia-resistant PDAC cells in in vivo-mimicking conditions. Proliferation, invasiveness and tumorigenicity in PDAC cells were significantly increased by reoxygenation. A Hedgehog (Hh) signaling component, Gli1, was significantly increased by reoxygenation. Gli1 knockdown inhibited reoxygenation-induced increases in proliferation and tumorigenicity and decreased invasiveness through suppression of matrix metalloproteinase (MMP) 2 and MMP9. Moreover, inhibition of Sonic Hh and Smoothened abrogated reoxygenation induced increases in proliferation and invasiveness. These results suggest that metastatic processes in PDAC are induced through activation of the Hh signaling pathway. Therefore, the Hh signaling pathway may be a therapeutic target for refractory PDAC in metastatic processes induced by reoxygenation.

Hedgehog signaling pathway is a potential therapeutic target for gallbladder cancer.

Gallbladder cancer (GBC) is a particularly deadly type of cancer with a 5-year survival rate of only 10%. New effective therapeutic strategies are greatly needed. Recently, we have shown that Hedgehog (Hh) signaling is reactivated in various types of cancer and is a potential therapeutic target. However, little is known about the biological significance of Hh signaling in human GBC. In this study, we determined whether Hh signaling could be a therapeutic target in GBC. The Hh transcription factor Gli1 was detected in the nucleus of GBC cells but not in the nucleus of normal gallbladder cells. The expression levels of Sonic Hh (Shh) and Smoothened (Smo) in human GBC specimens (n = 37) were higher than those in normal gallbladder tissue. The addition of exogenous Shh ligand augmented the anchor-dependent and anchor-independent proliferation and invasiveness of GBC cells in vitro. In contrast, inhibiting the effector Smo decreased the anchor-dependent and anchor-independent proliferation. Furthermore, the suppression of Smo decreased GBC cell invasiveness through the inhibition of MMP-2 and MMP-9 expression and inhibited the epithelial-mesenchymal transition. In a xenograft model, tumor volume in Smo siRNA-transfected GBC cells was significantly lower than in control tumors. These results suggest that Hh signaling is elevated in GBC and may be involved in the acquisition of malignant phenotypes, and that Hh signaling may be a potential therapeutic target for GBC.

Modulation of allograft immune responses by Porphyromonas gingivalis lipopolysaccharide administration in a rat model of kidney transplantation.

Periodontitis is a chronic inflammatory disease that affects the periodontal tissues. Although it is associated with various systemic diseases, the impact of periodontitis on kidney transplantation (KT) outcomes, particularly allograft rejection, remains unclear. This study investigated the effect of periodontitis on transplant immunity, specifically examining Porphyromonas gingivalis-derived lipopolysaccharide (LPS-PG). In vitro experiments revealed that LPS-PG increased regulatory T cells (Tregs) in Lewis rat spleen cells. In a mixed lymphocyte reaction assay, concentrations of interferon-γ, indicative of alloreactivity, were lower than in controls when LPS-PG was added to the culture and when LPS-PG-administered Lewis rat spleen cells were used as responders. In a rat KT model, LPS-PG administration to recipients promoted mild tubulitis and low serum creatinine and blood urea nitrogen levels 5 days post-KT compared with PBS-administered controls. Furthermore, LPS-PG-administered recipients had an elevated Treg proportion in their peripheral blood and spleen cells, and increased infiltrating Tregs in kidney allografts, compared with controls. The elevated Treg proportion in peripheral blood and spleen cells had a significant negative correlation with serum creatinine, suggesting elevated Tregs modulated allograft rejection. These findings suggest that periodontitis might modulate alloimmune reactivity through LPS-PG and Tregs, offering insights to refine immunosuppressive strategies for KT recipients.

Inhibition of PTPN3 Expressed in Activated Lymphocytes Enhances the Antitumor Effects of Anti-PD-1 Therapy in Head and Neck Cancer, Especially in Hypoxic Environments.

In the tumor microenvironment, wherein cytotoxic lymphocytes interact with cancer cells, lymphocyte exhaustion, an immune checkpoint inhibitor target, is promoted. However, the efficacy of these inhibitors is limited, and improving response rates remains challenging. We previously reported that protein tyrosine phosphatase nonreceptor type (PTPN) 3 is a potential immune checkpoint molecule for activated lymphocytes and that PTPN3 inhibition should be a focus area for cancer immunotherapy development. Therefore, in this study, we focused on PTPN3-suppressive therapy in terms of lymphocyte exhaustion under hypoxic conditions, which are a cancer microenvironment, and investigated measures for improving the response to anti-programmed death receptor (PD)-1 antibody drugs. We found that PTPN3 expression was upregulated in activated lymphocytes under hypoxic conditions, similar to the findings for other immune checkpoint molecules, such as PD-1, T cell immunoglobulin mucin-3, and lymphocyte-activation gene-3; furthermore, it functioned as a lymphocyte exhaustion marker. In addition, PTPN3-suppressed activated lymphocytes promoted the mammalian target of rapamycin (mTOR)-Akt signaling pathway activation and enhanced proliferation, migration, and cytotoxic activities under hypoxic conditions. Furthermore, PTPN3 suppression in activated lymphocytes increased PD-1 expression and enhanced the antitumor effects of anti-PD-1 antibody drugs against head and neck cancer in vitro and in vivo. These results suggest that the suppression of PTPN3 expression in activated lymphocytes enhances the therapeutic effect of anti-PD-1 antibody drugs in head and neck cancer, especially under hypoxic conditions that cause lymphocyte exhaustion.

Hedgehog Gli3 activator signal augments tumorigenicity of colorectal cancer via upregulation of adherence-related genes.

Hedgehog signal is re-activated in several cancers. In this study, we examined the role of Gli3 on malignant phenotype of tumorigenicity for colorectal cancer and its relationship with p53, WNT and ERK/AKT signals. Gli3 expression was detected in HT29 and SW480 (p53-mutant) cells, but not in DLD-1 (p53-mutant) or HCT116 (p53-wild type) cells by reverse transcription-polymerase chain reaction and immunocytochemistry. Full-length Gli3 transfection increased anchor-independent growth for all cells regardless of p53 status, with upregulation of adhesion-related genes. Exogenous Sonic-Hedgehog increased activator-type of Gli3 and colony formation in Gli3-positive HT29 and SW480 cells. After implantation of Gli3-FL or mock-transfectant DLD-1 cells into SCID mice, tumor formation was highly observed in only Gli3-FL-transfectant group. In clinical specimens, Gli3 expression was detected in subsets of colorectal cancer and related with poorly-differentiated histological type, while Sonic-Hedgehog was present with high incidence. In conclusion, activator Gli3 signal augments tumorigenicity of colorectal cancer irrespective of p53 status.

Intratumoral FOXP3+VEGFR2+ regulatory T cells are predictive markers for recurrence and survival in patients with colorectal cancer.

Previously, we have shown that CD8(+)T/FOXP3(+) cell ratio but not FOXP3(+) cell number alone is an independent prognostic factor for colorectal cancer. In the present study, we evaluated whether the number of intratumoral FOXP3(+)VEGFR2(+) (itFOXP3(+)VEGFR2(+)) T cells alone could be a predictive factor for survival prognosis in patients with colorectal cancer. Distribution of regulatory T cells (Tregs) at tumor sites derived from 88 patients with primary colorectal cancer was fluorescence-immunohistochemically examined. Relatively low number of itFOXP3(+)VEGFR2(+) cells significantly correlated with better [corrected] disease-free survival (DS) and overall survival (OS); multivariate analysis indicated that number of itFOXP3(+)VEGFR2(+) cells is an independent predictive and prognostic factor of DS and OS while neither intratumoral FOXP3(+) cell number nor intratumoral FOXP3(+)VEGFR2(-) cell number alone showed significant correlation with DS or OS. These results suggest that FOXP3(+)VEGFR2(+) may be a better predictive Treg marker than FOXP3(+) alone for recurrence and survival in patients with colorectal cancer.

The Hedgehog inhibitor suppresses the function of monocyte-derived dendritic cells from patients with advanced cancer under hypoxia.

Immunotherapy using monocyte derived dendritic cells (Mo-DCs) from cancer patients has been developed; however, the Mo-DCs regularly studied have been derived from non-cancer bearing donors or mice, and evaluated in normoxic conditions. In the present study, we investigated the effects of Hedgehog (Hh) inhibitors which are being developed as molecular target drugs for cancer on the functions of Mo-DCs derived from patients with advanced cancer when cultured in a tumor-like hypoxic environment. Mo-DC induction, migration, chemotaxis, phagocytosis, maturation, IL-12 p40 or p70 secretion and the allogeneic lymphocyte stimulation activity of Mo-DCs from patients with advanced cancer were all significantly inhibited by the Hh inhibitor, cyclopamine under hypoxic conditions. Our results suggest that Hh signaling plays an important role in the maintenance and function of Mo-DCs derived from patients with advanced cancer when cultured under hypoxic conditions.

The Hedgehog inhibitor cyclopamine impairs the benefits of immunotherapy with activated T and NK lymphocytes derived from patients with advanced cancer.

Hedgehog (Hh) signaling is activated in various types of cancer and contributes to the progression, proliferation, and invasiveness of cancer cells. Many Hh inhibitors are undergoing clinical trial and show promise as anticancer drugs. Hh signaling is also induced in the activated T and NK (TNK) lymphocytes that are used in immunotherapy. Activated TNK lymphocyte therapy is anticipated to work well within a tumor's hypoxic environment. However, most studies on the immunobiological functions of activated TNK lymphocytes have been conducted on healthy donor samples, under normoxic conditions. In the present study, we evaluated the effects of Hh inhibition and oxygen concentrations on the function of activated TNK lymphocytes derived from patients with advanced cancer. Proliferation, migration, surface NKG2D expression, and cytotoxicity were all significantly inhibited, and IFN-γ secretion was significantly increased upon Hh inhibitor treatment of activated TNK lymphocytes under hypoxic conditions in vitro. Tumors from mice injected with cyclopamine-treated activated TNK lymphocytes showed a significant increase in tumor size and had fewer apoptotic cells compared with the tumors in mice injected with control activated TNK lymphocytes. These results suggest that Hh signaling plays a pivotal role in activated TNK lymphocyte cell function. Combination therapy using Hh inhibitors and activated TNK lymphocytes derived from patients with advanced cancer may not be advantageous.

C4orf47 Contributes to the Induction of Stem-like Properties in Gallbladder Cancer Under Hypoxia.

BACKGROUND/AIM: Gallbladder cancer (GBC) is a refractory cancer with poor prognosis. Recently, therapy targeting the tumor microenvironment (TME) has gained attention. Cancer hypoxia is a significant factor in the tumor microenvironment (TME). Our research has shown that hypoxia activates several molecules and signaling pathways that contribute to the development of various types of cancer. Our analysis indicated that C4orf47 expression was up-regulated in a hypoxic environment and had a role in the dormancy of pancreatic cancer. There are no other reports on the biological significance of C4orf47 in cancer and its mechanism is still unknown. This study analyzed how C4orf47 affects refractory GBC to develop a new effective therapy for GBC. MATERIALS AND METHODS: Two human gallbladder carcinomas were used to examine how C4orf47 affects proliferation, migration, and invasion. C4orf47 was silenced using C4orf47 siRNA. RESULTS: C4orf47 was over-expressed in gallbladder carcinomas under hypoxic conditions. C4orf47 inhibition increased the anchor-dependent proliferation and decreased the anchor-independent colony formation of GBC cells. C4orf47 inhibition reduced epithelial-mesenchymal transition and suppressed migration and invasiveness of GBC cells. C4orf47 inhibition decreased CD44, Fbxw-7, and p27 expression and increased C-myc expression. CONCLUSION: C4orf47 enhanced invasiveness and CD44 expression, and reduced anchor-independent colony formation, suggesting that C4orf47 is involved in plasticity and the acquisition of the stem-like phenotype of GBC. This information is useful for the development of new therapeutic strategies for GBC.