Metastasis-related processes show various degrees of activation in different stages of pancreatic cancer rat liver metastasis

Machine learning-based approach for automated classification of cell and extracellular matrix using nanomechanical properties

Fibrosis characterized by excess accumulation of extracellular matrix (ECM) due to complex cell-ECM interactions plays a pivotal role in pathogenesis. Herein, we employ the pancreatic ductal adenocarcinoma (PDAC) model to investigate dynamic alterations in nanomechanical attributes arising from the cell-ECM interactions to study the fibrosis paradigm. Several segregated studies performed on cellular and ECM components fail to recapitulate their complex collaboration. We utilized collagen and fibronectin, the two most abundant PDAC ECM components, and studied their nanomechanical attributes. We demonstrate alteration in morphology and nanomechanical attributes of collagen with varying thicknesses of collagen gel. Furthermore, by mixing collagen and fibronectin in various stoichiometry, their nanomechanical attributes were observed to vary. To demonstrate the dynamicity and complexity of cell-ECM, we utilized Panc-1 and AsPC-1 cells with or without collagen. We observed that Panc-1 and AsPC-1 cells interact differently with collagen and vice versa, evident from their alteration in nanomechanical properties. Further, using nanomechanics data, we demonstrate that ML-based techniques were able to classify between ECM as well as cell, and cell subtypes in the presence/absence of collagen with higher accuracy. This work demonstrates a promising avenue to explore other ECM components facilitating deeper insights into tumor microenvironment and fibrosis paradigm.

Khasianine Affects the Expression of Sugar-Sensitive Proteins in Pancreatic Cancer Cells, Which Are Altered in Data from the Rat Model and Patients

Pancreatic ductal adenocarcinoma (PDAC) is a deadly malignancy with no effective treatment, particularly in the advanced stage. This study explored the antiproliferative activity of khasianine against pancreatic cancer cell lines of human (Suit2-007) and rat (ASML) origin. Khasianine was purified from Solanum incanum fruits by silica gel column chromatography and analyzed by LC-MS and NMR spectroscopy. Its effect in pancreatic cancer cells was evaluated by cell proliferation assay, chip array and mass spectrometry. Proteins showing sensitivity to sugars, i.e. sugar-sensitive lactosyl-Sepharose binding proteins (LSBPs), were isolated from Suit2-007 cells by competitive affinity chromatography. The eluted fractions included galactose-, glucose-, rhamnose- and lactose-sensitive LSBPs. The resulting data were analyzed by Chipster, Ingenuity Pathway Analysis (IPA) and GraphPad Prism. Khasianine inhibited proliferation of Suit2-007 and ASML cells with IC50 values of 50 and 54 μg/mL, respectively. By comparative analysis, khasianine downregulated lactose-sensitive LSBPs the most (126%) and glucose-sensitive LSBPs the least (85%). Rhamnose-sensitive LSBPs overlapped significantly with lactose-sensitive LSBPs and were the most upregulated in data from patients (23%) and a pancreatic cancer rat model (11.5%). From IPA, the Ras homolog family member A (RhoA) emerged as one of the most activated signaling pathways involving rhamnose-sensitive LSBPs. Khasianine altered the mRNA expression of sugar-sensitive LSBPs, some of which were modulated in data from patients and the rat model. The antiproliferative effect of khasianine in pancreatic cancer cells and the downregulation of rhamnose-sensitive proteins underscore the potential of khasianine in treating pancreatic cancer.

Modulation of the Endothelin System in Colorectal Cancer Liver Metastasis: Influence of Epigenetic Mechanisms?

Targeting of endothelin system genes is a promising strategy in cancer therapy. The modulation of these genes was explored in a model of colorectal cancer (CRC) liver metastasis and in a panel of CRC tumor cell lines that were exposed to the demethylating agent decitabine. The CC531 rat model mimicking CRC liver metastasis was used for tumor cell re-isolation and analysis of the endothelin system genes and DNA methyltransferases (DNMTs) by microarray. To mimic the effects caused by methylation changes, a panel of seven CRC cell lines was treated with the demethylating agent decitabine. Three genes of the endothelin system were potently modulated at messenger RNA (mRNA) level in rat CC531 cells during liver colonization. The concomitant decrease of two DNMTs suggested an influence from altered methylation. Changes in gene expression were also accomplished by exposure of CRC cells to the demethylating agent decitabine, when using daily low concentrations for 3 days, with minimal cytotoxic effects. Sensitive human SW480 cells showed an almost 100fold upregulation of endothelin-1 mRNA compared to untreated cells. This, however, was different in LS174T cells, which showed no significant increase in gene expression although the methylation levels were significantly decreased at a variety of corresponding loci. We suggest that the mechanism induced by methylation on gene expression in metastatic CRC cells can be compromised. The results question the overall success of treating metastatic CRC by methylation inhibitors.

Simultaneous resection of the primary tumour and liver metastases after conversion chemotherapy versus standard therapy in pancreatic cancer with liver oligometastasis: protocol of a multicentre, prospective, randomised phase III control trial (CSPAC-1)

INTRODUCTION

Approximately 50% of pancreatic ductal adenocarcinoma (PDAC) patients are diagnosed with distant metastasis, especially liver metastasis. The current standard treatment for these stage IV patients is palliative chemotherapy. There is increasing agreement that synchronous PDAC and liver metastasis resection may benefit highly selected patients. Thus, the Chinese Study Group for Pancreatic Cancer (CSPAC)-1 trial is being launched to establish a strategy for selecting PDAC patients with liver oligometastases who may benefit from synchronous resection after conversion chemotherapy.

METHODS AND ANALYSIS

In this study, liver oligometastasis is defined as no more than three metastatic lesions irrespective of their distribution within the liver lobes. The trial contains two steps. In the first step, 1000 to 1200 needle biopsy-confirmed PDAC patients with liver oligometastases are eligible for inclusion. Candidates will receive first-line chemotherapy. The RECIST V.1.1 criteria combined with tumour markers will be applied to evaluate the tumour response to chemotherapy every two cycles. Pancreatic cancer and hepatic metastasis resectability will be identified by multidisciplinary teams. Approximately 300 patients who meet our criteria will enter the second step and be randomly assigned at a 1:1 ratio to simultaneous resection of the primary pancreatic cancer lesion and liver oligometastases if no extensive metastatic sites are found during surgery or standard chemotherapy. Postoperative chemotherapy is recommended, and regimen selection should be based on the preoperative chemotherapy regimen. The primary endpoint is real overall survival (from enrolment to death). This study was activated in July 2018 and is expected to complete accrual within 5 years.

ETHICS AND DISSEMINATION

This trial has been approved by the Clinical Research Ethics Committee of Fudan University Shanghai Cancer Centre. Written informed consent will be obtained from all participants. Serious adverse events will be reported. Trial results will be submitted for peer-reviewed publication.

TRIAL REGISTRATION NUMBER

NCT03398291; Pre-results.

Pancreatic carcinoma cells colonizing the liver modulate the expression of their extracellular matrix genes

Liver is the main target of pancreatic ductal adenocarcinoma (PDAC) metastasis. Here, a rat model was used for analysing gene expression modulations during liver colonization. ASML PDAC cells were injected to isogenic rats and re-isolated at various stages of liver colonization for RNA isolation or re-cultivation. Microarrays were used for analysing mRNA and miRNA profiles of expres­sion. The results were partially confirmed by (q) RT-PCR and western blot. Selected genes were knocked down by siRNA transfection and the resulting cell behaviour was analysed. The ratio of up- and down regulated genes decreased from 20:1 (early stage) to 1.2:1 (terminal stage). Activation of cancer relevant gene categories varied between stages of liver colonization, with a nadir in the intermediate stage. The cells' environment triggered up to hundredfold changed expression for collagens, matrix metalloproteinases and chemokines. These modulations in mRNA expression were related to respective changes at miRNA levels. Gene expression knockdown of Mmp2 and Ccl20, which were highly modulated in vivo, was correlated with reduced prolif­eration and migration in vitro. Thus, target genes and temporal alterations in expression were identified, which can serve as basis for future therapeutic or diagnostic purposes.

Time to think: Selecting patients who may benefit from synchronous resection of primary pancreatic cancer and liver metastases

Pancreatic cancer remains a lethal disease and is associated with poor prognosis, particularly for patients with distant metastasis at diagnosis. Recently, Oweira reported a retrospective study that included 13233 metastatic pancreatic cancer patients from the Surveillance, Epidemiology and End Results database. They demonstrated that pancreatic cancer patients with isolated liver metastases had worse outcomes than patients with isolated lung metastases or distant nodal metastases. At present, the standard treatment for metastatic pancreatic cancer is chemotherapy. However, improvement in the safety of pancreatic surgery has led to the consideration of more aggressive surgical approaches. Schneitler reported two cases of hepatic metastatic pancreatic cancer in which negative margin (R0) resection and long survival were achieved after effective preoperative chemotherapy. In general, these two studies indicate that although pancreatic cancer patients with liver metastasis have a poor prognosis, surgical approaches may prolong survival for a few of these patients. A strategy to select hepatic metastatic pancreatic cancer patients who may benefit from surgical intervention is urgently needed.

The adaptation of colorectal cancer cells when forming metastases in the liver: expression of associated genes and pathways in a mouse model

Background

Colorectal cancer (CRC) is the second leading cause of cancer-related death in men and women. Systemic disease with metastatic spread to distant sites such as the liver reduces the survival rate considerably. The aim of this study was to investigate the changes in gene expression that occur on invasion and expansion of CRC cells when forming metastases in the liver.

Methods

The livers of syngeneic C57BL/6NCrl mice were inoculated with 1 million CRC cells (CMT-93) via the portal vein, leading to the stable formation of metastases within 4 weeks. RNA sequencing performed on the Illumina platform was employed to evaluate the expression profiles of more than 14,000 genes, utilizing the RNA of the cell line cells and liver metastases as well as from corresponding tumour-free liver.

Results

A total of 3329 differentially expressed genes (DEGs) were identified when cultured CMT-93 cells propagated as metastases in the liver. Hierarchical clustering on heat maps demonstrated the clear changes in gene expression of CMT-93 cells on propagation in the liver. Gene ontology analysis determined inflammation, angiogenesis, and signal transduction as the top three relevant biological processes involved. Using a selection list, matrix metallopeptidases 2, 7, and 9, wnt inhibitory factor, and chemokine receptor 4 were the top five significantly dysregulated genes.

Conclusion

Bioinformatics assists in elucidating the factors and processes involved in CRC liver metastasis. Our results support the notion of an invasion-metastasis cascade involving CRC cells forming metastases on successful invasion and expansion within the liver. Furthermore, we identified a gene expression signature correlating strongly with invasiveness and migration. Our findings may guide future research on novel therapeutic targets in the treatment of CRC liver metastasis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3342-1) contains supplementary material, which is available to authorized users.