Progranulin mediates immune evasion of pancreatic ductal adenocarcinoma through regulation of MHCI expression

Immune evasion is indispensable for cancer initiation and progression, although its underlying mechanisms in pancreatic ductal adenocarcinoma (PDAC) are not fully known. Here, we characterize the function of tumor-derived PGRN in promoting immune evasion in primary PDAC. Tumor- but not macrophage-derived PGRN is associated with poor overall survival in PDAC. Multiplex immunohistochemistry shows low MHC class I (MHCI) expression and lack of CD8⁺ T cell infiltration in PGRN-high tumors. Inhibition of PGRN abrogates autophagy-dependent MHCI degradation and restores MHCI expression on PDAC cells. Antibody-based blockade of PGRN in a PDAC mouse model remarkably decelerates tumor initiation and progression. Notably, tumors expressing LCMV-gp33 as a model antigen are sensitized to gp33-TCR transgenic T cell-mediated cytotoxicity upon PGRN blockade. Overall, our study shows a crucial function of tumor-derived PGRN in regulating immunogenicity of primary PDAC.

Immune responses to pancreatic ductal adenocarcinoma can be inhibited by cancer cells. Here the authors show that high levels of progranulin in PDAC inhibits immune responses by reducing MHC class I antigen presentation through enhanced degradation of MHC class I via autophagy.

Hepatic cancer stem cell marker granulin-epithelin precursor and β-catenin expression associate with recurrence in hepatocellular carcinoma

Granulin-epithelin precursor (GEP) has been demonstrated to confer enhanced cancer stem-like cell properties in hepatocellular carcinoma (HCC) cell line models in our previous studies. Here, we aimed to examine the GEP-expressing cells in relation to the stem cell related molecules and stem-like cell properties in the prospective HCC clinical cohort. GEP protein levels were significantly higher in HCCs than the paralleled non-tumor liver tissues, and associated with venous infiltration. GEP^high cells isolated from clinical HCC samples exhibited higher levels of stem cell marker CD133, pluripotency-associated signaling molecules β-catenin, Oct4, SOX2, Nanog, and chemodrug transporter ABCB5. In addition, GEP^high cells possessed preferential ability to form colonies and spheroids, and enhanced in vivo tumor-initiating ability while their xenografts were able to be serially subpassaged into secondary mouse recipients. Expression levels of GEP and pluripotency-associated genes were further examined in the retrospective HCC cohort and demonstrated significant correlation of GEP with β-catenin. Notably, HCC patients with high GEP and β-catenin levels demonstrated poor recurrence-free survival. In summary, GEP-positive HCC cells directly isolated from clinical specimens showed β-catenin elevation and cancer stem-like cell properties.

Granulin-epithelin precursor interacts with 78-kDa glucose-regulated protein in hepatocellular carcinoma

Background

Granulin-epithelin precursor (GEP) is a secretory growth factor, which has been demonstrated to control cancer growth, invasion, drug resistance and immune escape. Our previous studies and others also demonstrated its potential in targeted therapy. Comprehensive characterization of GEP partner on cancer cells are warranted. We have previously shown that GEP interacted with heparan sulfate on the surface of liver cancer cells and the interaction is crucial for GEP-mediated signaling transduction. This study aims to characterize GEP protein partner at the cell membrane with the co-immunoprecipitation and mass spectrometry approach.

Methods

The membrane fraction from liver cancer model Hep3B was used for capturing binding partner with the specific monoclonal antibody against GEP. The precipitated proteins were analyzed by mass spectrometry. After identifying the GEP binding partner, this specific interaction was validated in additional liver cancer cell line HepG2 by co-immunoprecipitation using GRP78 and GEP antibodies, respectively, as the bait. GRP78 transcript levels in hepatocellular carcinoma (HCC) clinical samples (n = 77 pairs) were examined by real-time quantitative RT-PCR. GEP and GRP78 protein expressions were investigated by immunohistochemistry on paraffin sections.

Results

We identified the GEP-binding protein as 78-kDa glucose-regulated protein (GRP78, also named heat shock 70-kDa protein 5, HSPA5). This interaction was validated in independent HCC cell lines. Increased GRP78 mRNA levels were demonstrated in liver cancer tissues compared with the paralleled liver tissues (t-test, P = 0.002). GRP78 and GEP transcript levels were significantly correlated (Spearman’s correlation, P = 0.001), and the proteins were also detectable in the cytoplasm of liver cancer cells by immunohistochemical staining.

Conclusions

GRP78 and GEP are interacting protein partners in liver cancer cells and may play a role in GEP-mediated cancer progression in HCC.

Comprehensive characterization of the patient-derived xenograft and the paralleled primary hepatocellular carcinoma cell line

BACKGROUND

Hepatocellular carcinoma (HCC) is an aggressive cancer with high mortality and morbidity worldwide. The limited clinically relevant model has impeded the development of effective HCC treatment strategy. Patient-derived xenograft (PDX) models retain most of the characteristics of original tumors and were shown to be highly predictive for clinical outcomes. Notably, primary cell line models allow in-depth molecular characterization and high-throughput analysis. Combined usage of the two models would provide an excellent tool for systematic study of therapeutic strategies. Here, we comprehensively characterized the novel PDX and the paralleled primary HCC cell line model.

METHODS

Tumor tissues were collected from HCC surgical specimens. HCC cells were sorted for in vivo PDX and in vitro cell line establishment by the expression of hepatic cancer stem cell marker to enhance cell viability and the rate of success on subsequent culture. The PDX and its matching primary cell line were authenticated and characterized in vitro and in vivo.

RESULTS

Among the successful cases for generating PDXs and primary cells, HCC40 is capable for both PDX and primary cell line establishment, which were then further characterized. The novel HCC40-PDX and HCC40-CL exhibited consistent phenotypic characteristics as the original tumor in terms of HBV protein and AFP expressions. In common with HCC40-PDX, HCC40-CL was tumorigenic in immunocompromised mice. The migration ability in vitro and metastatic properties in vivo echoed the clinical feature of venous infiltration. Genetic profiling by short tandem repeat analysis and p53 mutation pattern consolidated that both the HCC40-PDX and HCC40-CL models were derived from the HCC40 clinical specimen.

CONCLUSIONS

The paralleled establishment of PDX and primary cell line would serve as useful models in comprehensive studies for HCC pathogenesis and therapeutics development for personalized treatment.

Granulin-epithelin precursor renders hepatocellular carcinoma cells resistant to natural killer cytotoxicity

Immunoevasion is an emerging hallmark of cancer. Impairment of natural killer (NK) cytotoxicity is a mechanism to evade host immunosurveillance. Granulin-epithelin precursor (GEP) is a hepatic oncofetal protein regulating growth, invasion, and chemoresistance in hepatocellular carcinoma (HCC). We examined the role of GEP in conferring HCC cells the ability to evade NK cytotoxicity. In HCC cell lines, GEP overexpression reduced, whereas GEP suppression enhanced sensitivity to NK cytotoxicity. GEP downregulated surface expression of MHC class I chain-related molecule A (MICA), ligand for NK stimulatory receptor NK group 2 member D (NKG2D), and upregulated human leukocyte antigen-E (HLA-E), ligand for NK inhibitory receptor CD94/NKG2A. Functionally, GEP augmented production of soluble MICA, which suppressed NK activation. Matrix metalloproteinase (MMP)2 and MMP9 activity was involved partly in the GEP-regulated MICA shedding from HCC cells. In primary HCCs (n = 80), elevated GEP (P < 0.001), MICA (P < 0.001), and HLA-E (P = 0.089) expression was observed when compared with those in nontumor (n = 80) and normal livers (n = 10). Serum GEP (P = 0.010) and MICA (P < 0.001) levels were higher in patients with HCC (n = 80) than in healthy individuals (n = 30). High serum GEP and/or MICA levels were associated with poor recurrence-free survival (log-rank test, P = 0.042). Importantly, GEP blockade by mAbs sensitized HCC cells to NK cytotoxicity through MICA. In summary, GEP rendered HCC cells resistant to NK cytotoxicity by modulating MICA expression, which could be reversed by GEP blockade using antibody. Serum GEP and MICA levels are prognostic factors and can be used to stratify patients for targeted therapy.

Altered regulation of DNA ligase IV activity by aberrant promoter DNA methylation and gene amplification in colorectal cancer

Colorectal cancer (CRC) presents as a very heterogeneous disease which cannot sufficiently be characterized with the currently known genetic and epigenetic markers. To identify new markers for CRC we scrutinized the methylation status of 231 DNA repair-related genes by methyl-CpG immunoprecipitation followed by global methylation profiling on a CpG island microarray, as altered expression of these genes could drive genomic and chromosomal instability observed in these tumors. We show for the first time hypermethylation of MMP9, DNMT3A and LIG4 in CRC which was confirmed in two CRC patient groups with different ethnicity. DNA ligase IV (LIG4) showed strong differential promoter methylation (up to 60%) which coincided with downregulation of mRNA in 51% of cases. This functional association of LIG4 methylation and gene expression was supported by LIG4 re-expression in 5-aza-2'-deoxycytidine-treated colon cancer cell lines, and reduced ligase IV amounts and end-joining activity in extracts of tumors with hypermethylation. Methylation of LIG4 was not associated with other genetic and epigenetic markers of CRC in our study. As LIG4 is located on chromosome 13 which is frequently amplified in CRC, two loci were tested for gene amplification in a subset of 47 cases. Comparison of amplification, methylation and expression data revealed that, in 30% of samples, the LIG4 gene was amplified and methylated, but expression was not changed. In conclusion, hypermethylation of the LIG4 promoter is a new mechanism to control ligase IV expression. It may represent a new epigenetic marker for CRC independent of known markers.

Hand-assisted laparoscopic versus total laparoscopic right colectomy: a randomized controlled trial

AIM

Laparoscopic colectomy for colorectal cancer is associated with definite short-term benefits, and is increasingly practised worldwide. The limitations of a pure laparoscopic approach include a relative lack of tactile feedback and long procedural time. Hand-assisted laparoscopic surgery was introduced in an attempt to facilitate operation by improving the tactile sensation. To date, there is no consensus as to which approach is better. Herein we conducted a randomized controlled trial comparing hand-assisted laparoscopic colectomy (HALC) with total laparoscopic colectomy (TLC) in the management of right-sided colonic cancer.

METHODS

Adult patients with carcinoma of the caecum and ascending colon were recruited and randomized to undergo either HALC or TLC. Measured outcomes included operative time, blood loss, conversion rate, postoperative morbidities, postoperative pain, length of hospital stay, disease recurrence and patient survival.

RESULTS

Sixty patients (HALC=30, TLC=30) were recruited. The two groups were comparable with regard to age, gender distribution, body mass index and final histopathological staging. No difference was observed between the groups in terms of operating time, conversion rate, operative blood loss, pain score and length of hospital stay. With a median follow-up of 27 to 33 months, no difference was observed in terms of disease recurrence, and the 5-year survival rates remained similar (83%vs 80%, P=0.923).

CONCLUSION

HALC is safe and feasible, but it does not show any significant benefits over TLC in terms of operating time and conversion rate. Routine use of the hand-assisted laparoscopic technique in right hemicolectomy is therefore not recommended.

Hybrid NOTES colectomy for right-sided colonic tumors

INTRODUCTION

Given the limitation of surgical access and instrumentation, pure NOTES technique currently appears challenging for colorectal surgery. As such, we would like to determine the technical feasibility and clinical results of hybrid NOTES right hemicolectomy with transrectal extraction of specimen.

MATERIALS AND SURGICAL TECHNIQUE

After the right-sided colon was fully mobilized and vessels ligated, bowel resection and intracorporeal side-to-side ileocolic anastomosis were performed with endostaplers. The Transanal Endoscopic Operations device was inserted transanally. The resected specimen was removed via the Transanal Endoscopic Operations device through an enterotomy made over the anterior wall of the upper rectum.

DISCUSSION

The operation was performed on a 42-year-old woman and lasted 120 minutes; blood loss was 30 mL. The patient had an uneventful recovery and was discharged on postoperative day 5. The median pain score was 2 (range, 2-3). Our preliminary experience shows that hybrid NOTES right hemicolectomy is safe and feasible. The technique eliminates the need for mini-laparotomy in patients undergoing laparoscopic right hemicolectomy, and it offers promise in this era of minimally invasive surgery.

Adipose-derived stem cells from pregnant women show higher proliferation rate unrelated to estrogen

BACKGROUND

Adipose tissue contains an abundant population of multipotent adipose-derived stem cells (ASCs) and has been an excellent source of mesenchymal stem cells for cell therapy and tissue engineering. To ensure successful cell therapies, consistency of stem cell performance across donors is critical. However, the effect of the donor's reproductive status on ASC proliferation rate and differentiation capacity is undefined.

METHODS

We investigated whether the yield and function of ASCs are affected by the woman's reproductive status: pregnancy, premenopause or menopause. ASCs were isolated from the abdomen of 15 women and their proliferation rates and differentiation capacities were compared by cell count. The capacity of ASCs to differentiate into the chondrogenic lineage was investigated by quantitative real-time polymerase chain reaction and immunohistochemistry.

RESULTS

There was no significant difference in the differentiation capacity between the three groups, whereas the proliferation rate of ASCs from pregnant women was significantly higher than from the other two groups (P < 0.05). The proliferation rate of ASCs after estrogen treatment remained unchanged.

CONCLUSIONS

Despite the higher proliferation rate in pregnant women, ASCs showed consistency in cell differentiation capacity and were unaffected by donor status. This suggests that factors other than estrogen are responsible for the difference in proliferation.

Dopaminergic and adrenergic toxicities on SK-N-MC human neuroblastoma cells are mediated through G protein signaling and oxidative stress

Dopamine and norepinephrine are neurotransmitters which participate in various regulatory functions of the human brain. These functions are lost in neurodegenerative diseases including Parkinson's disease and Alzheimer's disease. In this study, we used SK-N-MC neuroblastoma cells to investigate the cytotoxicities of high concentrations of dopamine and norepinephrine on neuronal cells. Dopamine, norepinephrine, as well as their corresponding synthetic agonists (SKF38393 and isoproterenol, respectively) triggered SK-N-MC cell death when applied at 50-100 muM persistently for 2 days. This catecholamine-induced cell death appears to be neuronal specific, as demonstrated by their inabilities of triggering apoptosis of A549 lung carcinoma cells and Cos-7 kidney fibroblasts. By pretreating SK-N-MC cells with target-specific inhibitors before administration of catecholamine, components of G protein signaling (i.e. G( s )/cAMP/PKA), monoamine oxidases, nitric oxide synthase, c-Jun N-terminal kinase and oxidative stress were found to be involved in this dopamine/norepinephrine-induced cytotoxicity, which subsequently led to caspase-dependent and -independent apoptotic responses as well as DNA degradation. In contrast, agonists of G( i )-coupled dopamine receptors and adrenergic receptors (quinpirole and UK14,304, respectively) were incapable of triggering apoptosis of SK-N-MC cells. Our results suggest that both G protein (G( s ))-mediated signaling cascade and oxidative stress participate in the dopamine/norepinephrine-induced neuronal apoptosis.