Phase 2 study of vismodegib, a hedgehog inhibitor, combined with gemcitabine and nab-paclitaxel in patients with untreated metastatic pancreatic adenocarcinoma.

BACKGROUND: The Hedgehog (Hh) signalling pathway is overexpressed in pancreatic ductal adenocarcinoma (PDA). Preclinical studies have shown that Hh inhibitors reduce pancreatic cancer stem cells (pCSC), stroma and Hh signalling. METHODS: Patients with previously untreated metastatic PDA were treated with gemcitabine and nab-paclitaxel. Vismodegib was added starting on the second cycle. The primary endpoint was progression-free survival (PFS) as compared with historical controls. Tumour biopsies to assess pCSC, stroma and Hh signalling were obtained before treatment and after cycle 1 (gemcitabine and nab-paclitaxel) or after cycle 2 (gemcitabine and nab-paclitaxel plus vismodegib). RESULTS: Seventy-one patients were enrolled. Median PFS and overall survival (OS) were 5.42 months (95% confidence interval [CI]: 4.37-6.97) and 9.79 months (95% CI: 7.85-10.97), respectively. Of the 67 patients evaluable for response, 27 (40%) had a response: 26 (38.8%) partial responses and 1 complete response. In the tumour samples, there were no significant changes in ALDH + pCSC following treatment. CONCLUSIONS: Adding vismodegib to chemotherapy did not improve efficacy as compared with historical rates observed with chemotherapy alone in patients with newly diagnosed metastatic pancreatic cancer. This study does not support the further evaluation of Hh inhibitors in this patient population. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01088815.

Small-Molecule Inhibition of Axl Targets Tumor Immune Suppression and Enhances Chemotherapy in Pancreatic Cancer.

Activation of the receptor tyrosine kinase Axl is associated with poor outcomes in pancreatic cancer (PDAC), where it coordinately mediates immune evasion and drug resistance. Here, we demonstrate that the selective Axl kinase inhibitor BGB324 targets the tumor-immune interface to blunt the aggressive traits of PDAC cells in vitro and enhance gemcitibine efficacy in vivo Axl signaling stimulates the TBK1-NFκB pathway and innate immune suppression in the tumor microenvironment. In tumor cells, BGB324 treatment drove epithelial differentiation, expression of nucleoside transporters affecting gemcitabine response, and an immune stimulatory microenvironment. Our results establish a preclinical mechanistic rationale for the clinical development of Axl inhibitors to improve the treatment of PDAC patients.Significance: These results establish a preclinical mechanistic rationale for the clinical development of AXL inhibitors to improve the treatment of PDAC patients. Cancer Res; 78(1); 246-55. ©2017 AACR.

Potential risk factors for postoperative complications and deaths after laparoscopic cholecystectomy in the elderly.

Laparoscopic cholecystectomy (LC) is performed for gallbladder stones and cholecystitis in a large number of elderly patients. However, the safety of LC in the elderly is questioned. The aim of this study was to investigate predictive factors for the incidence of postoperative complications and deaths after LC in patients aged 80 years and older. Data from 85 elderly patients who underwent LC between January 2005 and December 2015 were prospectively collected in a database at our hospital. The following factors were compared for the occurrence of postoperative complications and deaths:age, gender, Body Mass Index, laboratory date, severity grade of cholecystitis, comorbidity of choledocholithiasis, conversion to open cholecystectomy, early or delayed LC, amount of time from onset to LC, operative duration, blood loss, and the following scoring systems for predicting risk of surgery:ECOG-PS, ASA, SIRS, CONUT, POSSUM, SAS, E-PASS. The complication rate of LC was 14.1% in this cohort. WBC, CRP, BUN, Cre, Na, PT-INR, severity of cholecystitis, conversion to open cholecystectomy, operative duration, early LC, ASA, SIRS, CONUT, POSSUM (PS, OS, complication rate), SAS, E-PASS (PRS, SSS, CRS) showed significant variability in univariate analysis. A high POSSUM score of complication and moderate or severe cholecystitis were independent risk factors for postoperative complication. Analysis of the ROC showed that the best cut-off point for the POSSUM score of complication was 51.5. LC for gallbladder stones and cholecystitis in elderly is a reliable operation, but the procedure for cases with a high score of the POSSUM for complications, or moderate or severe cholecystitis, may have the risk of postoperative complications in elderly patients.

Treatment of Pancreatic Cancer Patient-Derived Xenograft Panel with Metabolic Inhibitors Reveals Efficacy of Phenformin.

Purpose: To identify effective metabolic inhibitors to suppress the aggressive growth of pancreatic ductal adenocarcinoma (PDAC), we explored the in vivo antitumor efficacy of metabolic inhibitors, as single agents, in a panel of patient-derived PDAC xenograft models (PDX) and investigated whether genomic alterations of tumors correlate with the sensitivity to metabolic inhibitors.Experimental Design: Mice with established PDAC tumors from 6 to 13 individual PDXs were randomized and treated, once daily for 4 weeks, with either sterile PBS (vehicle) or the glutaminase inhibitor bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide (BPTES), transaminase inhibitor aminooxyacetate (AOA), pyruvate dehydrogenase kinase inhibitor dichloroacetate (DCA), autophagy inhibitor chloroquine (CQ), and mitochondrial complex I inhibitor phenformin/metformin.Results: Among the agents tested, phenformin showed significant tumor growth inhibition (>30% compared with vehicle) in 5 of 12 individual PDXs. Metformin, at a fivefold higher dose, displayed significant tumor growth inhibition in 3 of 12 PDXs similar to BPTES (2/8 PDXs) and DCA (2/6 PDXs). AOA and CQ had the lowest response rates. Gene set enrichment analysis conducted using the baseline gene expression profile of pancreatic tumors identified a gene expression signature that inversely correlated with phenformin sensitivity, which is in agreement with the phenformin gene expression signature of NIH Library of Integrated Network-based Cellular Signatures (LINCS). The PDXs that were more sensitive to phenformin showed a baseline reduction in amino acids and elevation in oxidized glutathione. There was no correlation between phenformin response and genetic alterations in KRAS, TP53, SMAD4, or PTENConclusions: Phenformin treatment showed relatively higher antitumor efficacy against established PDAC tumors, compared with the efficacy of other metabolic inhibitors and metformin. Phenformin treatment significantly diminished PDAC tumor progression and prolonged tumor doubling time. Overall, our results serve as a foundation for further evaluation of phenformin as a therapeutic agent in pancreatic cancer. Clin Cancer Res; 23(18); 5639-47. ©2017 AACR.

p62/sequestosome 1 in human colorectal carcinoma as a potent prognostic predictor associated with cell proliferation.

p62/sequestosome 1 (p62) is a multi-domain protein that functions as a receptor for ubiquitinated targets in the selective autophagy and serves as a scaffold in various signaling cascades. p62 have been reported to be up-regulated in several human malignancies, but the biological roles and significance of p62 are still poorly understood in colorectal carcinoma. We immunohistochemically evaluated p62 in 118 colorectal adenocarcinoma and 28 colorectal adenoma cases. We used four colon carcinoma cells (HCT8, HT29, COLO320, and SW480) in the in vitro studies. p62 immunoreactivity was detected in 11% of colorectal adenoma cases and 31% of adenocarcinoma cases, while it was negligible in the normal epithelium. The immunohistochemical p62 status was significantly associated with synchronous liver metastasis, and it turned out to be an independent adverse prognostic factor in colorectal cancer patients. Following in vitro studies revealed that HCT8 and HT29 cells transfected with p62-specific siRNA showed significantly decreased cell proliferation activity, whereas COLO320 and SW480 cells transfected with p62 expression plasmid showed significantly increased cell proliferation activity. The p62-mediated cell proliferation was not associated with the autophagy activity. These findings suggest that p62 promotes the cell proliferation mainly as a scaffold protein, and that the p62 status is a potent prognostic factor in colorectal carcinoma patients.

Hexokinase 2 in colorectal cancer: a potent prognostic factor associated with glycolysis, proliferation and migration.

BACKGROUND: It is well known that proliferating carcinoma cells preferentially use aerobic glycolysis rather than oxidative phosphorylation for energy production. Hexokinase 2 (HK2) plays a pivotal role in the glycolytic pathway. Previous studies have demonstrated that HK2 activity is markedly increased in various malignant neoplasms, but the clinical and biological significance of HK2 remain largely unclear in the colorectal carcinoma. PATIENTS AND METHODS: We performed immunohistochemistry for HK2 in 195 colorectal carcinoma tissues. We also used HCT8 and HT29 colon carcinoma cells in in vitro studies. RESULTS: HK2 immunoreactivity was detected in 100 out of 195 (51%) colorectal carcinoma tissues, and the immunohistochemical HK2 status was significantly associated with tumor size, depth of invasion, liver metastasis and TNM stage in these cases. Moreover, the HK2 status was significantly associated with increased incidence of recurrence and overall mortality of the patients, and multivariate analyses demonstrated that HK2 status was an independent prognostic factor for both disease-free and overall survival. Subsequent in vitro experiments revealed that both HCT8 and HT29 colon carcinoma cells transfected with specific siRNA for HK2 significantly decreased the lactate production, proliferation activity and migration property. CONCLUSION: These results suggest that HK2 plays important roles in the glycolytic, proliferation and migration properties of colorectal carcinoma and, therefore, HK2 status is a potent worse prognostic factor in colorectal cancer patients.

Superior therapeutic efficacy of nab-paclitaxel over cremophor-based paclitaxel in locally advanced and metastatic models of human pancreatic cancer.

BACKGROUND: Albumin-bound paclitaxel (nab-paclitaxel, nab-PTX) plus gemcitabine (GEM) combination has demonstrated efficient antitumour activity and statistically significant overall survival of patients with metastatic pancreatic ductal adenocarcinoma (PDAC) compared with GEM monotherapy. This regimen is currently approved as a standard of care treatment option for patients with metastatic PDAC. It is unclear whether cremophor-based PTX combined with GEM provide a similar level of therapeutic efficacy in PDAC. METHODS: We comprehensively explored the antitumour efficacy, effect on metastatic dissemination, tumour stroma and survival advantage following GEM, PTX and nab-PTX as monotherapy or in combination with GEM in a locally advanced, and a highly metastatic orthotopic model of human PDAC. RESULTS: Nab-PTX treatment resulted in significantly higher paclitaxel tumour plasma ratio (1.98-fold), robust stromal depletion, antitumour efficacy (3.79-fold) and survival benefit compared with PTX treatment. PTX plus GEM treatment showed no survival gain over GEM monotherapy. However, nab-PTX in combination with GEM decreased primary tumour burden, metastatic dissemination and significantly increased median survival of animals compared with either agents alone. These therapeutic effects were accompanied by depletion of dense fibrotic tumour stroma and decreased proliferation of carcinoma cells. Notably, nab-PTX monotherapy was equivalent to nab-PTX plus GEM in providing survival advantage to mice in a highly aggressive metastatic PDAC model, indicating that nab-PTX could potentially stop the progression of late-stage pancreatic cancer. CONCLUSIONS: Our data confirmed that therapeutic efficacy of PTX and nab-PTX vary widely, and the contention that these agents elicit similar antitumour response was not supported. The addition of PTX to GEM showed no survival advantage, concluding that a clinical combination of PTX and GEM may unlikely to provide significant survival advantage over GEM monotherapy and may not be a viable alternative to the current standard-of-care nab-PTX plus GEM regimen for the treatment of PDAC patients.

Therapeutic Targeting of the Warburg Effect in Pancreatic Cancer Relies on an Absence of p53 Function.

The "Warburg effect" describes a peculiar metabolic feature of many solid tumors, namely their increased glucose uptake and high glycolytic rates, which allow cancer cells to accumulate building blocks for the biosynthesis of macromolecules. During aerobic glycolysis, pyruvate is preferentially metabolized to lactate by the enzyme lactate dehydrogenase-A (LDH-A), suggesting a possible vulnerability at this target for small-molecule inhibition in cancer cells. In this study, we used FX11, a small-molecule inhibitor of LDH-A, to investigate this possible vulnerability in a panel of 15 patient-derived mouse xenograft (PDX) models of pancreatic cancer. Unexpectedly, the p53 status of the PDX tumor determined the response to FX11. Tumors harboring wild-type (WT) TP53 were resistant to FX11. In contrast, tumors harboring mutant TP53 exhibited increased apoptosis, reduced proliferation indices, and attenuated tumor growth when exposed to FX11. [18F]-FDG PET-CT scans revealed a relative increase in glucose uptake in mutant TP53 versus WT TP53 tumors, with FX11 administration downregulating metabolic activity only in mutant TP53 tumors. Through a noninvasive quantitative assessment of lactate production, as determined by 13C magnetic resonance spectroscopy (MRS) of hyperpolarized pyruvate, we confirmed that FX11 administration inhibited pyruvate-to-lactate conversion only in mutant TP53 tumors, a feature associated with reduced expression of the TP53 target gene TIGAR, which is known to regulate glycolysis. Taken together, our findings highlight p53 status in pancreatic cancer as a biomarker to predict sensitivity to LDH-A inhibition, with regard to both real-time noninvasive imaging by 13C MRS as well as therapeutic response.

Combined Inhibition of Cyclin-Dependent Kinases (Dinaciclib) and AKT (MK-2206) Blocks Pancreatic Tumor Growth and Metastases in Patient-Derived Xenograft Models.

KRAS is activated by mutation in the vast majority of cases of pancreatic cancer; unfortunately, therapeutic attempts to inhibit KRAS directly have been unsuccessful. Our previous studies showed that inhibition of cyclin-dependent kinase 5 (CDK5) reduces pancreatic cancer growth and progression, through blockage of the centrally important RAL effector pathway, downstream of KRAS. In the current study, the therapeutic effects of combining the CDK inhibitor dinaciclib (SCH727965; MK-7965) with the pan-AKT inhibitor MK-2206 were evaluated using orthotopic and subcutaneous patient-derived human pancreatic cancer xenograft models. The combination of dinaciclib (20 mg/kg, i.p., three times a week) and MK-2206 (60 mg/kg, orally, three times a week) dramatically blocked tumor growth and metastasis in all eight pancreatic cancer models examined. Remarkably, several complete responses were induced by the combination treatment of dinaciclib and MK-2206. The striking results obtained in these models demonstrate that the combination of dinaciclib with the pan-AKT inhibitor MK-2206 is promising for therapeutic evaluation in pancreatic cancer, and strongly suggest that blocking RAL in combination with other effector pathways downstream from KRAS may provide increased efficacy in pancreatic cancer. Based on these data, an NCI-CTEP-approved multicenter phase I clinical trial for pancreatic cancer of the combination of dinaciclib and MK-2206 (NCT01783171) has now been opened.

Autophagy is critical for pancreatic tumor growth and progression in tumors with p53 alterations.

UNLABELLED: Pancreatic ductal adenocarcinoma is refractory to available therapies. We have previously shown that these tumors have elevated autophagy and that inhibition of autophagy leads to decreased tumor growth. Using an autochthonous model of pancreatic cancer driven by oncogenic Kras and the stochastic LOH of Trp53, we demonstrate that although genetic ablation of autophagy in the pancreas leads to increased tumor initiation, these premalignant lesions are impaired in their ability to progress to invasive cancer, leading to prolonged survival. In addition, mouse pancreatic cancer cell lines with differing p53 status are all sensitive to pharmacologic and genetic inhibition of autophagy. Finally, a mouse preclinical trial using cohorts of genetically characterized patient-derived xenografts treated with hydroxychloroquine showed responses across the collection of tumors. Together, our data support the critical role of autophagy in pancreatic cancer and show that inhibition of autophagy may have clinical utility in the treatment of these cancers, independent of p53 status. SIGNIFICANCE: Recently, a mouse model with embryonic homozygous Trp53 deletion showed paradoxical effects of autophagy inhibition. We used a mouse model with Trp53 LOH (similar to human tumors), tumor cell lines, and patient-derived xenografts to show that p53 status does not affect response to autophagy inhibition. These findings have important implications on ongoing clinical trials.

[A case of advanced gallbladder cancer with mediastinum lymph node metastasis successfully treated with multimodality therapy].

A 69 -year-old female with advanced gallbladder cancer underwent cholecystectomy, S4a/S5 segmentectomy of the liver, and resection of the extra-hepatic bile duct in October 2005. Adjuvant chemotherapy consisted of gemcitabine (GEM) and tegafururacil (UFT) administered consecutively. Four years after surgery, computed tomography revealed a single enlarged lymph node in the mediastinum, along with ¹8F-fluorodeoxyglucose accumulation and increased carcinoembryonic antigen (CEA) levels. Therefore, the mediastinal lymph node was considered to be a metastasis and GEM was readministered. Although the patient was treated with GEM for 1 year, the accumulation of 18F-fluorodeoxyglucose in the lymph node remained elevated. No other distant metastases were detected. Abronchoscopic biopsy histologically confirmed mucinous adenocarcinoma in the lymph node. Thus, the mediastinal lymph node was resected. Post-surgery, there was no evidence of recurrence during the 30-month follow up period without chemotherapy. Herein, we report a successful case of surgical treatment for solitary mediastinal lymph node metastasis of gallbladder cancer and review the relevant literature.

[A case of pancreatic cancer with local recurrence and liver metastases eight years after surgery].

Here we report a rare case of late recurrence of pancreatic cancer 8 years after surgery. A woman in her mid-fifties was hospitalized for examination of epigastralgia. Computed tomography (CT) revealed a 4 cm nodule at the pancreatic head with suspected invasion of the superior mesenteric vein. She underwent pancreaticoduodenectomy with wedge resection of superior mesenteric vein and intraoperative radiation therapy. Pathological findings showed moderately differentiated tubular adenocarcinoma and T3N1M0, Stage IIB according to The Union for International Cancer Control (UICC) TNM classification. As adjuvant chemotherapy, 56 courses of gemcitabine (GEM) were administered in 3.5 years. Because of long-term use of GEM, common terminology criteria for adverse events (CTCAE) Grade 3 anemia occurred, and chemotherapy was discontinued. Tumor markers were evaluated every month and CT scans were taken every 6 months for 5 years. Subsequently, CT was performed annually. The patient was hospitalized for high-grade fever, 8.5 years after surgery. CT, magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET-CT) detected local recurrence with liver metastases. GEM was administered again, but was ineffective. The patient died 9 years after surgery. In conclusion, even if long-term survival is achieved in pancreatic cancer, follow-ups should not be stopped.

MicroRNA 223 is upregulated in the multistep progression of Barrett's esophagus and modulates sensitivity to chemotherapy by targeting PARP1.

PURPOSE: Recent microarray and RNA-sequencing studies have uncovered aberrantly expressed microRNAs (miRNA) in Barrett's esophagus-associated esophageal adenocarcinoma. The functional significance of these miRNAs in esophageal adenocarcinoma initiation and progression is largely unknown. EXPERIMENTAL DESIGN: Expression levels of miR-199a/b-3p, -199a-5p, -199b-5p, -200b, -200c, -223, and -375 were determined in microdissected tissues from cardiac mucosa, Barrett's esophagus, dysplastic Barrett's esophagus, and esophageal adenocarcinoma using quantitative real-time PCR. miR-223 expression was validated in precursors and esophageal adenocarcinomas from 95 patients with esophageal adenocarcinoma by in situ hybridization (ISH). miR-223 was transfected into two esophageal adenocarcinoma cell lines, and in vitro assays were conducted. Target genes were identified using Illumina microarray, and results were validated in cell lines and human specimens. RESULTS: miR-199 family members and miR-223 were significantly overexpressed in esophageal adenocarcinoma, however, only miR-223 showed a stepwise increase during esophageal adenocarcinoma carcinogenesis. A similar trend was observed by ISH, which additionally showed that miR-223 is exclusively expressed by the epithelial compartment. miR-223-overexpressing cells had statistically significantly more migratory and invasive potential than scramble sequence-transfected cells. PARP1 was identified as a direct target gene of miR-223 in esophageal adenocarcinoma cells. Increased sensitivity to chemotherapy was observed in cells with enforced miR-223 expression and reduced PARP1. CONCLUSIONS: miR-223 is significantly upregulated during the Barrett's esophagus-dysplasia-esophageal adenocarcinoma sequence. Although high miR-223 levels might contribute to an aggressive phenotype, our results also suggest that patients with esophageal adenocarcinoma with high miR-223 levels might benefit from treatment with DNA-damaging agents.

Notch signaling pathway targeted therapy suppresses tumor progression and metastatic spread in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDA) remains a lethal human malignancy with historically limited success in treatment. The role of aberrant Notch signaling, which requires the constitutive activation of γ-secretase, in the initiation and progression of PDA is well defined and inhibitors of this pathway are currently in clinical trials. Here we investigated the in vivo therapeutic effect of PF-03084014, a selective γ-secretase inhibitor, alone and in combination with gemcitabine in pancreatic cancer xenografts. PF-03084014 treatment inhibited the cleavage of nuclear Notch 1 intracellular domain and Notch targets Hes-1 and Hey-1. Gemcitabine treatment showed good response but not capable of inducing tumor regressions and targeting the tumor-resident cancer stem cells (CD24(+)CD44(+) and ALDH(+) tumor cells). A combination of PF-03084014 and gemcitabine treatment resulted tumor regression in 3 of 4 subcutaneously implanted xenograft models. PF-03084014, and in combination with gemcitabine reduced putative cancer stem cells, indicating that PF-03084014 target the especially dangerous and resilient cancer stem cells within pancreatic tumors. Tumor re-growth curves plotted after drug treatments demonstrated that the effect of the combination therapy was sustainable than that of gemcitabine. Notably, in a highly aggressive orthotopic model, PF-03084014 and gemcitabine combination was effective in inducing apoptosis, inhibition of tumor cell proliferation and angiogenesis, resulting in the attenuation of primary tumor growth as well as controlling metastatic dissemination, compared to gemcitabine treatment. In summary, our preclinical data suggest that PF-03084014 has greater anti-tumor activity in combination with gemcitabine in PDA and provides rationale for further investigation of this combination in PDA.

[Efficacy of neoadjuvant chemotherapy for resectable pancreatic carcinoma].

Surgery followed by adjuvant chemotherapy is standard care for resectable pancreatic carcinoma. The maximum estimated 2-year survival rate associated with this strategy is nearly 50%. The use of neoadjuvant therapy for pancreatic cancer remains controversial, and its efficacy has not been elucidated. To evaluate the efficacy of neoadjuvant chemotherapy for planned pancreatic cancer resection, the oncological outcomes of neoadjuvant gemcitabine plus S-1 combination therapy( GS therapy) and a surgery-first approach were retrospectively compared. Patients with planned pancreatic cancer resection and without major artery abutments were enrolled in this study. There were 39 cases of neoadjuvant GS therapy (N group) and 93 cases of the surgery-first approach( S group). Survival and surrogate markers, including the R0 rate, the "true R0 rate"( R0 with tumor marker normalization after resection), and N0 rate, were compared. The groups did not differ significantly in terms of age, gender, or tumor location. The resection rates of the N and S groups were similar (92% and 86%, respectively). The median survival of the N group (39.4 months) was significantly longer than that of the S group (20.8 months) in intention-to-treat analysis (p=0.0009). The R0, true R0, and N0 rates of the N group (85%, 69%, and 44%, respectively) were higher than those of the S group( 72%, 48%, and 24%, respectively). In conclusion, this retrospective analysis showed that neoadjuvant GS therapy might be more effective than the standard surgery-first strategy in terms of oncological outcomes for resectable pancreatic cancer. A prospective randomized study, Prep-02/JSAP-05, which compares neoadjuvant therapy to the surgery-first approach, is ongoing (UMIN-No. 000009634).

The gamma secretase inhibitor MRK-003 attenuates pancreatic cancer growth in preclinical models.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy, with most patients facing an adverse clinical outcome. Aberrant Notch pathway activation has been implicated in the initiation and progression of PDAC, specifically the aggressive phenotype of the disease. We used a panel of human PDAC cell lines as well as patient-derived PDAC xenografts to determine whether pharmacologic targeting of Notch pathway could inhibit PDAC growth and potentiate gemcitabine sensitivity. MRK-003, a potent and selective γ-secretase inhibitor, treatment resulted in the downregulation of nuclear Notch1 intracellular domain, inhibition of anchorage-independent growth, and reduction of tumor-initiating cells capable of extensive self-renewal. Pretreatment of PDAC cells with MRK-003 in cell culture significantly inhibited the subsequent engraftment in immunocompromised mice. MRK-003 monotherapy significantly blocked tumor growth in 5 of 9 (56%) PDAC xenografts. A combination of MRK-003 and gemcitabine showed enhanced antitumor effects compared with gemcitabine in 4 of 9 (44%) PDAC xenografts, reduced tumor cell proliferation, and induced both apoptosis and intratumoral necrosis. Gene expression analysis of untreated tumors indicated that upregulation of NF-κB pathway components was predictive of sensitivity to MRK-003, whereas upregulation in B-cell receptor signaling and nuclear factor erythroid-derived 2-like 2 pathway correlated with response to the combination of MRK-003 with gemcitabine. Our findings strengthen the rationale for small-molecule inhibition of Notch signaling as a therapeutic strategy in PDAC.

Overexpression of adenovirus-mediated p27kip1 lacking the Jab1-binding region enhances cytotoxicity and inhibits xenografted human cholangiocarcinoma growth.

The cyclin-dependent kinase inhibitor (CDK1) p27(kip1) is a negative regulator of cell cycling and has antitumor effects. In our previous study, the recombinant adenovirus expressing wild-type p27(kip1) (Adp27-wt) induced cell cycle arrest and apoptosis, and proved that p27 is a tumor suppressor gene like p53. Another adenovirus vector expressing mutant p27(kip1) (Adp27-mt), which inhibited degradation by the ubiquitin-proteasome system, showed increased protein stability and caused a stronger induction of apoptosis. Recently, the p27(kip1) protein binding with Jab1 (Jun activating binding protein 1) was found to translocate from the nucleus into the cytosol, and then become degraded by the 26S proteasome system. The inhibition of nuclear-cytoplasmic translocation increases the protein stability of p27(kip1) and p27(kip1) with a deletion of the Jab1-binding region (p27-jab-d) is not translocated and not degraded. Therefore, a new recombinant adenovirus (Adp27-jab-d) expressing p27-jab-d was made which was able to induce greater cytotoxicity. Adp27-jab-d inhibited the growth of human cholangiocarcinoma cell line (TFK-1) cells in vitro at 3.3 times (IC(50)) lower concentration than Adp27-wt. Moreover, in a xenografted severe combined immuno-deficient (SCID) mouse model injected with TFK-1 cells in the subcutaneous tissue, treatment by intratumor injection of Adp27-jab-d once a day for 3 days after the tumor was established, inhibited tumor growth more strongly than Adp27-wt or Adp27-mt and even induced tumor regression. However, the flow cytometric TUNEL assay showed little enhancement of apoptosis. Adp27-jab-d was thought to induce not only apoptosis but also necrosis, which was due to a specific effect of the Adp27-jab-d. Thus, by enhancing the cytotoxicity through inhibiting the translocaton of p27(kip1), p27(kip1) lacking the Jab1-binding region might be useful for cancer therapy. The control protein localization might also be a new target not only for cancer treatment, but also other diseases.

ZD1839 (IRESSA) stabilizes p27Kip1 and enhances radiosensitivity in cholangiocarcinoma cell lines.

The prognosis of cholangiocarcinoma patients is extremely poor despite the aggressive multidisciplinary cancer therapies that have been used clinically (1). Recently, molecular target therapy has attracted attention. Epidermal growth factor receptor (EGFR) tyrosine kinase (TK) is a promising target for anticancer therapy. ZD1839 (IRESSA) is an orally active, selective inhibitor of EGFR-TK. This study examined the effects of ZD1839 in TFK-1 and HuCCT1, the human cholangiocarcinoma cell lines that express EGFR. Somatic mutations in the TK domain of the EGFR gene are associated with the sensitivity of lung cancers to ZD1839 (2). In the analysis of the EGFR sequence, no mutations were found in TFK-1 and HuCCT1. The TFK-1 and HuCCT1 cells showed almost the same sensitivity to ZD1839. It is shown that ZD1839 induced apoptotic cell death of TFK-1 cells as indicated by apoptotic morphological changes and an enhancement of TUNEL-positive cells. ZD1839 produced a dose-dependent inhibition of cellular proliferation in TFK-1. Cell cycle analysis demonstrated that ZD1839 induces G1 arrest. Moreover, concurrent evaluation of the expression of p27(Kip1) protein and Jun activating domain-binding protein 1 (Jab1) with ZD1839 by Western blotting analysis was performed. It was found that ZD1839 activity causes an increase of p27(Kip1) stability that correlates with Jab1 down-regulation. Thus, ZD1839 affects key cellular pathways, controlling cell proliferation and apoptosis. Furthermore, the treatment of TFK-1 with ZD1839 reduced the cell survival after radiation exposure. ZD1839 in combination with radiation produced a dose-dependent and synergic inhibitory effect on cellular proliferation. In conclusion, these results suggest that ZD1839 may have clinical activity against cholangiocarcinoma.

Clock gene mouse period2 overexpression inhibits growth of human pancreatic cancer cells and has synergistic effect with cisplatin.

Circadian rhythms are the daily oscillations of multiple biological processes regulated by an endogenous clock. The Period2 gene is essential in controlling the circadian rhythm and plays an important role in tumor suppression. We examined whether the overexpression of the mouse Period2 gene (mPer2) in cultured tumor cells from human tissues inhibits cell growth, using the recombinant adenovirus vector AdmPer2. The overexpression of mPer2 in human pancreatic cancer cells (Panc1, Aspc1) reduced cellular proliferation and induced apoptotic cell death. Infection with AdmPer2 also inhibited cell-cycle progression, inducing arrest at the G(2)-M phase. Western blotting analyses confirmed that infection with AdmPer2 reduced Bcl-X(L), Cdc2 and cyclin B1 protein, whereas it increased Bax protein in Aspc1 cells. The overexpression of mPer2 suppressed Cdc2 kinase activity. Moreover, infection with AdmPer2 resulted in dose-dependent synergic cell killing effects with the anticancer agent cisplatin (CDDP) in human pancreatic cancer cells. This synergic effect might be related to the reduction of Bcl-X(L) induced by infection with AdmPer2. Our results suggest that the circadian gene Period2 may play an important role in suppression of cell proliferation in human cancer, and additionally Period2 gene expression level may influence the sensitivity to cisplatin depending on Bcl-X(L) expression level.

Up-regulated p27Kip1 reduces matrix metalloproteinase-9 and inhibits invasion of human breast cancer cells.

BACKGROUND: p27Kip1 is a cyclin-dependent kinase inhibitor which has been reported to be associated with invasion, metastasis and angiogenesis in malignant tumors, but its mechanism of action remains unknown. Here, it was examined whether p27Kip1 has an inhibitory effect on cancer cell invasion and correlates with matrix metalloproteinase expression (MMPs). MATERIAL AND METHODS: The human breast cancer cell line MDA-MB-231 and MDA-MB-231 transfectedp27Kip1 MDA-MB-p27 were used for the invasion assay, Western blotting and real-time quantitative RT-PCR. RESULTS: In the invasion assay, the invasion of MDA-MB-p27 was significantly less than that of the parent cell line. In Western blotting analyses, the protein level of MMP-9 was also reduced in MDA-MB-p27. Furthermore, the activity of MMP-9 in cell culture supernatants was lower in MDA-MB-p27 as compared with enzyme-linked immunosorbent assays. In real-time quantitative RT-PCR, the mRNA level of MMP-9 was lower in MDA-MB-p27 cells. CONCLUSION: Up-regulation of p27Kip1 remarkably inhibited the invasion of the breast cancer cells, in part due to the reduced expression of MMP-9. This is the first report of p27Kip1 modulating MMP-9 and indicating that p27Kip1 might play a key role in tumor cell invasion.