PTPN3 Could Βe a Therapeutic Target of Pancreatic Cancer.

BACKGROUND/AIM: Recently, protein tyrosine phosphatase non-receptor type 3 (PTPN3) has gained attention. However, the role of PTPN3 in cancer has not been fully elucidated. In the present study, we analyzed the role of PTPN3 in pancreatic cancer and investigated whether PTPN3 could be a new therapeutic target for pancreatic cancer. MATERIALS AND METHODS: Two pancreatic ductal adenocarcinoma (PDAC) cell lines were used as target cells. Cell proliferation was investigated using cell counting and a xenograft mouse model. Migration and invasion were analyzed using Transwell inserts. Activation-related signaling molecules were examined by western blotting. RESULTS: PTPN3 contributes to the proliferation, migration, and invasion of PDAC cells in vitro. PTPN3 promotes tumor growth in a mouse xenograft model, an action mediated partially through the MAPK pathway. CONCLUSION: PTPN3 could be a new therapeutic target for pancreatic cancer.

Cancer therapy that targets the Hedgehog signaling pathway considering the cancer microenvironment (Review).

Recently, the cancer microenvironment (CME) has received significant attention. At the local site of the tumor, cancer progression is affected by secreted cytokines and conditions derived from the CME and stimulation by cancer­induced cytokines in an autocrine manner. The CME is characterized by various types of conditions, such as hypoxia, inflammation stimulation, and angiogenesis, and contains various components, such as reactive oxygen species, cancer­associated fibroblasts, infiltrated immune cells, exosomes, and cancer stem cells (CSCs). These conditions and components complicate the progression of cancer. The Hedgehog (HH) signaling pathway is a morphogenesis signaling pathway that is reactivated in some cancers. In these cancers, reactivated HH signaling is involved in the induction of the malignant phenotype. HH signaling is also activated under hypoxic conditions and is considered to be strongly correlated with the CME, including the induction of cancer fibrosis and maintenance of CSCs. The aim of the present review was to elucidate a cancer therapy that targets HH signaling by considering the CME, particularly focusing on hypoxia.

TrkB/BDNF Signaling Could Be a New Therapeutic Target for Pancreatic Cancer.

BACKGROUND/AIM: Tropomyosin-related kinase B (TrkB)/brain-derived neurotrophic factor (BDNF) signaling plays a role in inducing malignant phenotypes in several aggressive types of cancers. To create a conclusive therapy targeting TrkB/BDNF signaling in solid refractory cancers, the biological significance of TrkB/BDNF signaling was analyzed in pancreatic ductal adenocarcinoma (PDAC) cells. MATERIALS AND METHODS: Three PDAC cell lines were used as target cells to investigate proliferation and invasiveness. Small interfering RNA (siRNA) and the TrkB tyrosine kinase inhibitor k252a were used as TrkB/BDNF signaling inhibitors. RESULTS: All PDAC cell lines expressed TrkB and BDNF. When TrkB and BDNF were inhibited by siRNA or k252a, the invasiveness of PANC-1 and SUIT-2 cells significantly decreased. When TrkB was inhibited by siRNA or k252a, proliferation was significantly inhibited in PDAC cells. CONCLUSION: TrkB/BDNF signaling may be a new therapeutic target for PDAC. Therapies targeting TrkB/BDNF signaling may be a conclusive cancer therapy for refractory solid cancer.

Voltage-Controlled Anodic Oxidation of Porous Fluorescent SiC for Effective Surface Passivation.

This study investigated the fabrication of porous fluorescent SiC using a constant voltage-controlled anodic oxidation process. The application of a high, constant voltage resulted in a spatial distinction between the porous structures formed inside the fluorescent SiC substrates, due to the different etching rates at the terrace and the large step bunches. Large, dendritic porous structures were formed as the etching process continued and the porous layer thickened. Under the conditions of low hydrofluoric acid (HF) concentration, the uniformity of the dendritic porous structures through the entire porous layer was considerably improved compared with the conditions of high HF concentration. The resulting large uniform structure offered a sizable surface area, and promoted the penetration of atomic layer-deposited (ALD) Al2O3 films (ALD-Al2O3). The emission intensity in the porous fluorescent SiC was confirmed via photoluminescence (PL) measurements to be significantly improved by a factor of 128 after ALD passivation. With surface passivation, there was a clear blueshift in the emission wavelength, owing to the effective suppression of the non-radiative recombination rate in the porous structures. Furthermore, the spatial uniformity of emitted light was examined via PL mapping using three different excitation lasers, which resulted in the observation of uniform and distinctive emissions in the fluorescent SiC bulk and porous areas.

Hypoxia and pancreatic ductal adenocarcinoma.

Chemotherapy and immunotherapy for pancreatic ductal adenocarcinoma (PDAC) have limited success. One reason for this is thought to be the cancer microenvironment surrounding PDAC. Hypoxia is a feature of the cancer microenvironment. Under hypoxia, different various molecules and signaling pathways are activated compared with normoxia. To develop a new effective therapeutic strategy for PDAC, we need to target these hypoxic conditions to overcome PDAC. To inhibit the malignant phenotype, the cellular changes that occur under hypoxia should be elucidated. Various molecules and signaling that are activated by hypoxia may contribute to the induction of malignant phenotypes of PDAC such as proliferation, invasion, tumorigenesis, chemosensitivity, and autophagy. If we can develop therapeutic approaches to target one of these molecules or signaling pathways, we may proceed to the next therapeutic step of successfully treating refractory PDAC.

Liprin-α4 as a New Therapeutic Target for SCLC as an Upstream Mediator of HIF1α.

BACKGROUND/AIM: Small-cell lung cancer (SCLC) remains one of deadliest types of cancers. Cis-diamminedichloroplatinum (CDDP) is a key chemotherapeutic agent for SCLC, however, its therapeutic effect is limited. Recently, hypoxia in the cancer microenvironment has been suggested to influence the effect of cancer therapy. MATERIALS AND METHODS: Using small interfering RNA inhibition of leukocyte common antigen-related interacting protein alpha 4 (liprin-α4), and of hypoxia-inducible factor (HIF)-1α, proliferation, invasion, migration and chemosensitivity were investigated in SBC-5 SCLC cells, under normoxia and hypoxia. RESULTS: Liprin-α4 was found to contribute to proliferation, but not migration and invasion of SBC-5 cells both under normoxia and hypoxia. Inhibition of liprin-α4 increased chemosensitivity of SBC-5 cells under hypoxia. Liprin-α4 signaling occurs through mitogen-activated protein kinase pathways via activation of HIF1α expression. Inhibition of HIF1α reduced proliferation and increased chemosensitivity of SBC-5 cells under hypoxia. CONCLUSION: Liprin-α4 inhibition may enhance the effect of CDDP and liprin-α4 might be a novel therapeutic target in SCLC.

RBPJ and MAML3: Potential Therapeutic Targets for Small Cell Lung Cancer.

BACKGROUND/AIM: Small cell lung cancer (SCLC) is still a deadly type of cancer for which there are few effective therapeutic strategies. Development of a new molecule targeting agent is urgently desired. Previously we showed that recombination signal binding protein for immunoglobulin-kappa-J region (RBPJ) and mastermind-like 3 (MAML3) are new therapeutic targets for pancreatic cancer. In the present study, we analyzed whether RBPJ/MAML3 inhibition could also be a new therapeutic strategy for SCLC. MATERIALS AND METHODS: Using silencing of RBPJ/MAML3, proliferation, invasion, migration and chemosensitivity of SBC-5 cells were investigated. RESULTS: RBPJ/MAML3 inhibition reduced Smoothened and HES1 expression, suggesting that RBPJ/MAML3 signaling was through Hedgehog and NOTCH pathways. In the analysis of cell functions, RBPJ/MAML3 inhibition significantly reduced proliferation and invasiveness via reduction of expression of matrix metalloproteinases. On the other hand, RBPJ/MAML3 inhibition also reduced chemosensitivity to cis-diamminedichlo-roplatinum and gemcitabine. CONCLUSION: These results suggest that RBPJ and MAML3 could be new therapeutic targets for SCLC, however, chemosensitivity may be reduced in combinational use with other chemo-therapeutic agents.

Liprin-α4 as a Possible New Therapeutic Target for Pancreatic Cancer.

BACKGROUND/AIM: In pancreatic cancer, where the microenvironment is extremely hypoxic, analyzing signal transduction under hypoxia is thought to be significantly important. By investigating microarray analysis of pancreatic cancer cells cultured under both normoxia and hypoxia, we found that the expression of leukocyte common antigen-related (LAR)-interacting protein (liprin)-α4 was extremely increased under hypoxia compared to under normoxia. MATERIALS AND METHODS: In the present study, the biological significance of liprin-α4 in pancreatic cancer was investigated and whether liprin-α4 has potential as a therapeutic target for pancreatic cancer was estimated. RESULTS: Suppression of liprin-α4 reduced proliferation of pancreatic cancer cells both in vitro and in vivo. Inhibition of liprin-α4 also reduced invasiveness through the suppression of endothelial-mesenchymal transition. Stimulation by liprin-α4 was through phosphoinositide 3-kinase and mitogen-activated protein kinase signaling pathways. CONCLUSION: Liprin-α4 plays a pivotal role in inducing malignant phenotypes such as increased proliferation and invasion in pancreatic cancer, and that liprin-α4 could be a new effective therapeutic target for pancreatic cancer.

Hedgehog Inhibition Upregulates TRK Expression to Antagonize Tumor Suppression in Small Cell Lung Cancer Cells.

BACKGROUND/AIM: Previously we have shown that tropomyosin-related kinase B (TRKB) and Hedgehog (Hh) signalling pathways induce malignant phenotypes in many cancer types. However, results from small cell lung cancer (SCLC) clinical trials using TRK and Hh inhibitors have been disappointing. One reason for this may be the existence of crosstalk between TRKB and Hh signalling pathways. In this study, we detected negative crosstalk between the TRKB and Hh-GLI1 signalling pathways. MATERIALS AND METHODS: The human small cell lung carcinoma cell line, SBC-5, was used. Using small interfering RNA to inhibit TRKB and Hh signalling, whether TRKB and Hh signaling contribute to proliferation and invasiveness in SBC-5 cells were investigated. RESULTS: TRKB expression in GLI1 siRNA-transfected SBC-5 cells was higher than that of control cells. GLI1-knockdown alone did not affect invasiveness of SBC-5 cells. However, combined knockdown of TRKB and GLI1 significantly decreased invasiveness. Moreover, combined TRKB and GLI1 knockdown inhibited proliferation and migration to a greater extent than when either was inhibited alone. CONCLUSION: These results suggest that Hh inhibition increases TrkB expression to counter tumor suppression in SBC-5 cells. The combined use of TRKB and Hh inhibitors may, therefore, be useful for the treatment of refractory SCLC.

Feasibility of laparoscopic surgery for complex Crohn's disease of the small intestine.

BACKGROUND: The laparoscopic approach for complex Crohn's disease (CD), which involves abscess formation, fistula formation, and recurrent CD, is controversial. The aim of this study was to investigate the feasibility and safety of the laparoscopic approach for complex CD. METHODS: Fifty-six patients who had undergone surgery for CD of the small bowel from January 2007 to August 2014 were divided into two groups: the laparoscopic approach for complex CD group (LC group, n = 31) and the laparoscopic approach for simple CD group (LS group, n = 25). The preoperative data and surgical outcomes of the LC group were compared with those of the LS groups. RESULTS: There were no significant differences in preoperative data and operating time between the two groups. Blood loss was not significantly different between the LC and LS groups. The incision length was longer in the LC group than the LS group (P = 0.004). The incidence of severe postoperative complications in the LC group was higher than in the LS group (P = 0.026). The length of postoperative stay was similar in the LC and LS groups. CONCLUSIONS: The laparoscopic approach for complex CD is feasible and provides good cosmesis that is comparable to that offered by simple CD.

Laparoscopic lateral pelvic lymph node dissection is achievable and offers advantages as a minimally invasive surgery over the open approach.

BACKGROUND: Laparoscopic lateral pelvic lymph node dissection (LPLD) is a minimally invasive alternative to open surgical therapy for advanced low rectal cancer patients. This study assessed potential risk factors for lateral pelvic lymph node metastasis (LPLM) and evaluated the feasibility and oncological safety of laparoscopic LPLD compared with the conventional open approach. METHODS: We retrospectively reviewed the clinical records of 90 patients with advanced low rectal cancer who underwent LPLD following total mesorectal excision at Kyushu University Hospital between January 2001 and July 2014. We compared the clinicopathological features between the patients with and without LPLM and the surgical outcomes between patients who underwent laparoscopic LPLD (LL) and open LPLD (OL). RESULTS: Fourteen (15.6 %) patients had LPLM. Univariate analysis revealed that undifferentiated cancer, positive lymphatic invasion, >50 % circumferential cancer extent, mesorectal lymph node metastases (MLM), and distant metastasis were associated with LPLM. In the multivariate analysis, MLM was the only independent risk factor for LPLM. Forty-six (51.1 %) patients underwent LL, and 44 (48.9 %) patients underwent OL. The mean surgical duration was longer in the LL group than in the OL group (641.0 vs. 312.0 min, P < 0.001). The LL group also had less hemorrhage (252.0 vs. 815.0 mL, P < 0.001) and a shorter hospital stay (22.9 vs. 29.1 days, P = 0.04) than the OL group. The mean number of harvested lateral pelvic lymph nodes was larger in the LL group than in the OL group (19.5 vs. 15.8, P < 0.05). The morbidity rate and overall survival (3-year OS: 94.7 vs. 82.9 %, P = 0.25) did not differ between the two groups. CONCLUSIONS: Patients with advanced low rectal cancer presenting MLM are good candidates for LPLD. Laparoscopic LPLD enables retrieval of more lymph nodes and may be acceptable for the treatment of advanced low rectal cancer.

Reduced-port laparoscopic restorative proctocolectomy without diverting ileostomy.

INTRODUCTION: We introduced a reduced-port procedure for laparoscopic restorative proctocolectomy without diverting ileostomy for patients with familial adenomatous polyposis and ulcerative colitis. MATERIALS AND SURGICAL TECHNIQUE: A multichannel port was inserted through a 2.5-cm umbilical incision. A 12-mm port in the right lower abdomen and a 3- or 5-mm port were also employed. A proctocolectomy was performed intracorporeally, and the entire colon and rectum were delivered through the umbilical incision. An ileal J-pouch was made extracorporeally following division of the mesenteric vessels. Ileal j-pouch-anal anastomosis was performed intracorporeally or transanally after rectal mucosectomy. A drain was inserted through the 12-mm port incision, and a transanal decompression tube was placed in the pouch. Two women and one man underwent this surgery, and their postoperative recovery was uneventful. DISCUSSION: Laparoscopic restorative proctocolectomy without a diverting stoma by a reduced-port technique is feasible and provides excellent cosmetic outcomes in selected patients.

Lipopolysaccharide (LPS) increases the invasive ability of pancreatic cancer cells through the TLR4/MyD88 signaling pathway.

BACKGROUND: Inflammation plays a multifaceted role in cancer progression, and NF-kappaB is one of the key factors connecting inflammation with cancer progression. We have shown that lipopolysaccharide (LPS) promotes NF-kappaB activation in colon cancer cells and pancreatic cancer cells. However, it is unclear why inflammatory stimuli can induce NF-kappaB activation in cancer cells. METHODS: We used two human pancreatic cancer cells, Panc-1 and AsPC-1, as target cells. LPS was used as an inflammatory stimulus. To confirm the participation of TLR4/NF-kappaB signaling pathway, we used three different NF-kappaB inhibitors (PDTC, IkappaBalpha mutant, and NF-kappaB decoy ODN) and siRNAs (against TLR4, MyD88, and MMP-9). Effect of LPS on pancreatic cancer cell invasive ability was determined by Matrigel invasion assay. RESULTS: LPS increased the invasive ability of pancreatic cancer cells, while blockade of NF-kappaB pathway decreased the LPS-dependent increased invasive ability. Blockade of TLR4 or MyD88 by siRNA also decreased the LPS-dependent increased invasive ability. CONCLUSION: These results suggest that TLR/MyD88/NF-kappaB signaling pathway plays a significant role in connecting inflammation and cancer invasion and progression.

Enhancement of paclitaxel-induced apoptosis by inhibition of mitogen-activated protein kinase pathway in colon cancer cells.

Resistance to chemotherapy represents a major obstacle to improving the survival of patients with colorectal cancer. In this study, the inhibition of the mitogen-activated protein kinase (MAPK) pathway was demonstrated to markedly enhance the apoptosis of colon cancer cells induced by paclitaxel, one of the key chemotherapeutic drugs widely used to treat various types of cancer. The treatment of the colon cancer cell lines SW480 and DLD-1 with paclitaxel resulted in increased activation of the MAPK pathway, which was blocked by PD98059, a MEK inhibitor. In both cell lines, MAPK inhibition by PD98059 led to a dramatic enhancement of the paclitaxel-induced apoptosis, as determined by cell cycle analysis and Hoechst 33342 staining, although the inhibitor alone did not affect apoptosis. This effect was restricted to paclitaxel since PD98059 did not alter the sensitivity to other drugs, including 5-fluorouracil (5-FU) and camptothecin (CPT). Importantly, selective blockage of the MAPK pathway by small interfering RNA (siRNA) also increased the apoptotic cell death induced by paclitaxel. These findings highlight the importance of the MAPK pathway in paclitaxel-induced apoptosis and suggest that a combined treatment with paclitaxel and MEK inhibitors could be an attractive therapeutic strategy against colon cancer.

Gli1 contributes to the invasiveness of pancreatic cancer through matrix metalloproteinase-9 activation.

The hedgehog (Hh) signaling pathway has been reported to be associated with the growth of pancreatic cancer, but its role in the invasive phenotype is poorly understood. Therefore, we investigated the role of the Hh pathway in pancreatic cancer cell invasiveness using a Matrigel invasion assay. Blockade of the Hh pathway by cyclopamine inhibited pancreatic cancer cell invasion in association with a decreased expression of matrix metalloproteinase (MMP)-9. By contrast, activation of the Hh pathway by the addition of exogenous Sonic hedgehog increased cell invasion and MMP-9 expression. Stable transfection of pancreatic cancer cells with Gli1 increased their invasiveness, which was associated with activation of MMP-9. We also showed that inhibition of MMP-9 by small interfering RNA blocked the increased invasiveness of Gli1-transfected cells. Furthermore, inhibition of Gli1 by small interfering RNA suppressed the invasiveness and MMP-9 expression of pancreatic cancer cells. Taken together, these findings suggest that members of the Hh pathway, especially Gli1, play an important role in the invasiveness of pancreatic cancer cells through the regulation of MMP-9 expression.

Crosstalk of hedgehog and Wnt pathways in gastric cancer.

Morphogenic signals like Hedgehog (Hh) and Wnt are reported to play critical roles in the progression of gastric cancer. We aimed to assess the relationship between Hh and Wnt signaling pathways. In 58 gastric cancer specimens, Wnt pathway activation was inversely correlated with Hh pathway activation. When AGS gastric cancer cells, in which Wnt signaling was constitutively active, were used as a target cell line, Gli1 overexpression suppressed Wnt transcriptional activity, nuclear beta-catenin accumulation and proliferation of AGS cells. Knock-down of beta-catenin by siRNA suppressed Wnt pathway activity and proliferation of AGS cells. Our data may provide some clues for the treatment of gastric cancer associated with Wnt signaling activation.

Gamma-secretase inhibitors enhance taxane-induced mitotic arrest and apoptosis in colon cancer cells.

BACKGROUND & AIMS: Colorectal cancers are resistant to conventional chemotherapeutic treatments, including taxanes. gamma-Secretase is a multimeric membrane protein complex responsible for the intramembrane proteolysis of various type I transmembrane proteins, including amyloid beta-precursor protein and Notch. gamma-Secretase inhibitors have attracted increasing interest as anticancer drugs because of their ability to inhibit Notch signaling. However, the therapeutic usefulness of gamma-secretase inhibitors against colorectal cancers remains unclear. METHODS: The effects of gamma-secretase inhibitors on growth and apoptosis induced by various chemotherapeutic agents in colon cancer cells were evaluated using Hoechst 33342 staining, colony formation assay, and cell cycle analysis. The effect of gamma-secretase inhibitors on taxane-induced mitotic arrest was evaluated using the cyclin B1-associated histone H1 kinase assay and MPM-2 reactivity. The involvement of Notch signaling was evaluated by the silencing of Notch/CBF1 signaling by RNA interference. RESULTS: gamma-Secretase inhibitors enhanced taxane-induced mitotic arrest and apoptosis of colon cancer cells both in vitro and in vivo, although gamma-secretase inhibitors alone did not affect growth and apoptosis of colon cancer cells. We also showed that this effect by gamma-secretase inhibitors was restricted to taxanes and colon cancer cells. Silencing of Notch/CBF1 signaling failed to affect paclitaxel-induced mitotic arrest and apoptosis. CONCLUSIONS: These data suggest that gamma-secretase inhibitors could be a new therapeutic modality for overcoming resistance to taxanes in colorectal cancers.

Anti-patched-1 antibodies suppress hedgehog signaling pathway and pancreatic cancer proliferation.

BACKGROUND: The hedgehog (Hh) signaling pathway is aberrantly activated in many human carcinomas including pancreatic cancer and regulates tumor cell growth. Overproduction of sonic hedgehog (Shh), a ligand of the Hh signaling pathway, increases the Hh signaling activity through transmitting the signal to patched-1 (Ptch1), the receptor of the Hh signaling pathway. MATERIALS AND METHODS: a-Ptch1 antibodies were raised against an oligo-peptide, designed according to the Ptch1 aminoacid sequence. The specificity of a-Ptch1 was examined by immunoblotting and immuno-fluorescence, and biological effects were detected by RT-PCR and cell proliferation assay using two pancreatic cancer cell lines, Panc1 and SUIT-2. RESULTS: a-Ptch1 recognized a 160 kDa protein as shown by immunoblotting and cell surface staining of pancreatic cancer cells. Incubation with a-Ptch1 suppressed Hh signaling activity and proliferation of pancreatic cancer cells. CONCLUSION: These results provide a new strategy for controling Hh dependent development of pancreatic cancer and other Hh related carcinomas.

Hedgehog signaling pathway is a possible therapeutic target for gastric cancer.

BACKGROUND AND OBJECTIVES: It has been shown that the hedgehog (Hh) signaling pathway is activated in gastric cancer. To investigate the viability of the Hh pathway as a therapeutic target, we analyzed activation of the Hh pathway in gastric cancer. METHODS: Surgically resected gastric carcinoma specimens and lymph nodes were analyzed immunohistochemically. We used the percentage of cancer cells with nuclear translocation of Gli1 as a marker of Hh pathway activation. RESULTS: Nuclear localization of Gli1 was higher in 28 undifferentiated-type tumors than in 30 differentiated-type tumors. Eighteen of the fifty-eight cancer specimens consisted of a mixture of a histologically predominant part and a small area with different histology. In these 18 tumors, the percentage of cells showing nuclear staining of Gli1 was higher in the undifferentiated-type part than in the differentiated-type part. Nuclear staining of Gli1 in primary tumors was positively correlated with lymph node metastasis. The Gli1 nuclear staining percentage of metastatic lymph nodes correlated closely with that of each primary carcinoma. Cyclopamine, a Hh pathway inhibitor, suppressed the growth of gastric cancer cells in vitro. CONCLUSIONS: The Hh pathway may be a useful therapeutic target for such as undifferentiated-type gastric cancer with lymph node metastasis.