Hepatocyte growth factor inhibits anoikis of pancreatic carcinoma cells through phosphatidylinositol 3-kinase pathway

Prediction and validation of anoikis-related genes in neuropathic pain using machine learning

BACKGROUND

Neuropathic pain (NP) can be induced by a variety of clinical conditions, such as spinal cord injury, lumbar disc herniation (LDH), lumbar spinal stenosis, diabetes, herpes zoster, and spinal cord tumors, and inflammatory stimuli. The pathogenesis of NP is extremely complex. Specifically, in LDH, the herniated nucleus pulposus exerts mechanical pressure on nerve roots, triggering local inflammation and consequent NP. Anoikis, a special form of programmed cell death, is closely related to the progression of NP. In this study, we sought to clarify the molecular characteristics of anoikis-related genes in NP, providing novel insights for the diagnosis and treatment of NP.

METHODS

We screened NP-related genes based on the GSE124272 dataset and obtained 439 anoikis-related genes from the GeneCards database. Through Least Absolute Shrinkage and Selection Operator (LASSO) and Support Vector Machine (SVM) machine learning algorithms, six key hub genes were identified: hepatocyte growth factor (HGF), matrix metalloproteinase 13 (MMP13), c-abl oncogene 1, non-receptor tyrosine kinase (ABL1), elastase neutrophil expressed (ELANE), fatty acid synthase (FASN), and long non-coding RNA (Linc00324). Functional enrichment analyses, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), alongside Gene Set Enrichment Analysis (GSEA) and immune infiltration analysis, were performed on these hub genes. Additionally, transcription factors and potential therapeutic drugs were predicted. We also used rats to construct an NP model and validated the analyzed hub genes using hematoxylin and eosin (H&E) staining, real-time polymerase chain reaction (PCR), and Western blotting assays.

RESULTS

Our data indicated that anoikis-related genes have diagnostic value in NP patients, as confirmed by experimental results. Moreover, this study elucidated the role of these genes in immune infiltration during the pathogenesis of NP and identified potential therapeutic drugs targeting these key genes.

CONCLUSION

This study further explores the pathogenesis of NP and provides certain reference value for developing targeted therapeutic strategies, thereby improving NP management.

Phase Ib and Expansion Study of Gemcitabine, Nab-Paclitaxel, and Ficlatuzumab in Patients With Metastatic Pancreatic Cancer

BACKGROUND

In preclinical pancreatic ductal adenocarcinoma (PDAC) models, inhibition of hepatocyte growth factor (HGF) signaling using ficlatuzumab, a recombinant humanized anti-HGF antibody, and gemcitabine reduced tumor burden.

METHODS

Patients with previously untreated metastatic PDAC enrolled in a phase Ib dose escalation study with 3 + 3 design of 2 dose cohorts of ficlatuzumab 10 and 20 mg/kg administered intravenously every other week with gemcitabine 1000 mg/m2 and albumin-bound paclitaxel 125 mg/m2 given 3 weeks on and 1 week off. This was followed by an expansion phase at the maximally tolerated dose of the combination.

RESULTS

Twenty-six patients (sex, 12 male:14 female; median age, 68 years [range, 49-83 years]) were enrolled, 22 patients were evaluable. No dose-limiting toxicities were identified (N = 7 pts) and ficlatuzumab at 20 mg/kg was chosen as the maximum tolerated dose. Among the 21 patients treated at the MTD, best response by RECISTv1.1: 6 (29%) partial response, 12 (57%) stable disease, 1 (5%) progressive disease, and 2 (9%) not evaluable. Median progression-free survival and overall survival times were 11.0 months (95% CI, 7.6-11.4 months) and 16.2 months (95% CI, 9.1 months to not reached), respectively. Toxicities attributed to ficlatuzumab included hypoalbuminemia (grade 3, 16%; any grade, 52%) and edema (grade 3, 8%; any grade, 48%). Immunohistochemistry for c-Met pathway activation demonstrated higher tumor cell p-Met levels in patients who experienced response to therapy.

CONCLUSION

In this phase Ib trial, ficlatuzumab, gemcitabine, and albumin-bound paclitaxel were associated with durable treatment responses and increased rates of hypoalbuminemia and edema.

Targeting Growth Factor Signaling Pathways in Pancreatic Cancer: Towards Inhibiting Chemoresistance

Pancreatic cancer is one of the most deadly cancers, ranking amongst the top leading cause of cancer related deaths in developed countries. Features such as dense stroma microenvironment, abnormal signaling pathways, and genetic heterogeneity of the tumors contribute to its chemoresistant characteristics. Amongst these features, growth factors have been observed to play crucial roles in cancer cell survival, progression, and chemoresistance. Here we review the role of the individual growth factors in pancreatic cancer chemoresistance. Importantly, the interplay between the tumor microenvironment and chemoresistance is explored in the context of pivotal role played by growth factors. We further describe current and future potential therapeutic targeting of these factors.

Targeting the HGF/c-MET pathway in advanced pancreatic cancer: a key element of treatment that limits primary tumour growth and eliminates metastasis

BACKGROUND

Stromal-tumour interactions facilitate pancreatic cancer (PC) progression. The hepatocyte growth factor (HGF)/c-MET pathway is upregulated in PC and mediates the interaction between cancer cells and stromal pancreatic stellate cells (PSCs). This study assessed the effect of HGF/c-MET inhibition plus gemcitabine (G) on the progression of advanced PC.

METHODS

Orthotopic PC was produced by implantation of luciferase-tagged human cancer cells + human PSCs into mouse pancreas. Tumours were allowed to develop without treatment for 4 weeks. Mice were then treated for 6 weeks with one of the following: IgG, G, HGF inhibitor (Hi), c-MET inhibitor (Ci), Hi + Ci, Hi + G, Ci + G, or Hi + Ci + G.

RESULTS

Bioluminescence imaging showed similar tumour sizes in all mice at the initiation of treatments. Triple therapy (Hi + Ci + G): (1) completely eliminated metastasis; (2) significantly reduced tumour size as assessed by bioluminescence and at necropsy; (3) significantly reduced proliferating cancer cell density and stem cell marker DCLK1 expression in tumours. In vitro 3D culture studies supported our in vivo findings.

CONCLUSION

Even at an advanced disease stage, a two-pronged approach, targeting (a) HGF/c-MET with relevant inhibitors and (b) cancer cells with chemotherapy, completely eliminated metastasis and significantly decreased tumour growth, suggesting that this is a promising treatment approach for PC.

Midkine promotes hepatocellular carcinoma metastasis by elevating anoikis resistance of circulating tumor cells

Midkine is overexpressed in hepatocellular carcinoma (HCC) and plays a role in tumor progression, but less is known about its role in resistance of circulating tumor cells (CTCs) to anoikis which leading to recurrence and metastasis. The aim of the present study was to analyze whether midkine was associated with HCC progression with anoikis resistance. We found that cultured HCC cells were more resistant to anoikis, which paralleled midkine expression, and midkine treatment significantly inhibited anoikis in a dose-dependent manner. Furthermore, in in vitro and in vivo assays, knockdown of midkine resulted in significant sensitivity to anoikis, decreased cell survival and significantly decreased tumor occurrence rate. Patients with midkine-elevated HCC had higher CTC counts and less apoptotic CTCs, as well as significantly higher recurrence rate and shorter recurrence-free interval. To understand the molecular mechanism underlying the midkine with HCC progression, we performed in vitro and in vivo studies. We found that midkine plays an important role in enhancement of HCC cell resistance to anoikis, thereby promoting subsequent metastasis. Activation of PI3K/Akt/NF-κB/TrkB signaling by midkine-activated anaplastic lymphomakinase (ALK) is responsible for anoikis resistance.

Targeting the HGF/c-MET pathway: stromal remodelling in pancreatic cancer

Stromal-tumor interactions in pancreatic cancer (PC) impact on treatment outcomes. Pancreatic stellate cells (PSCs) produce the collagenous stroma of PC and interact with cancer cells to facilitate disease progression. A candidate growth factor pathway that may mediate this interaction is the hepatocyte growth factor (HGF)/c-MET pathway. HGF is produced by PSCs and its receptor c-MET is expressed on pancreatic cancer cells. We studied the effects on PC progression of inhibiting the HGF/c-MET pathway in the presence and absence of a representative chemotherapeutic agent, gemcitabine. Using an orthotopic model of PC we have shown that "triple therapy" (inhibition of both HGF and c-MET combined with gemcitabine) resulted in the greatest reduction in tumor volume compared to each of the treatments alone or in dual combinations. Importantly, metastasis was virtually eliminated in mice receiving triple therapy. Our in vivo findings were supported by in vitro studies showing that the increase in cancer cell proliferation and migration in response to PSC secretions was significantly inhibited by the triple regimen. Our studies suggest that a combined approach, that targets tumor cells by chemotherapy while inhibiting specific pathways that mediate stromal-tumor interactions, may represent a novel therapeutic strategy to improve outcomes in PC.

Concise Review: Pancreatic Cancer and Bone Marrow-Derived Stem Cells

Pancreatic adenocarcinoma remains one of the most challenging diseases of modern gastroenterology, and, even though considerable effort has been put into understanding its pathogenesis, the exact molecular mechanisms underlying the development and/or systemic progression of this malignancy still remain unclear. Recently, much attention has been paid to the potential role of bone marrow-derived stem cells (BMSCs) in this malignancy. Hence, herein, we comprehensively review the most recent discoveries and current achievements and concepts in this field. Specifically, we discuss the significance of identifying pancreatic cancer stem cells and novel therapeutic approaches involving molecular interference of their metabolism. We also describe advances in the current understanding of the biochemical and molecular mechanisms responsible for BMSC mobilization during pancreatic cancer development and systemic spread. Finally, we summarize experimental, translational, and/or clinical evidence regarding the contribution of bone marrow-derived mesenchymal stem cells, endothelial progenitor cells, hematopoietic stem/progenitor cells, and pancreatic stellate cells in pancreatic cancer development/progression. We also present their potential therapeutic value for the treatment of this deadly malignancy in humans.

SIGNIFICANCE

Different bone marrow-derived stem cell populations contribute to the development and/or progression of pancreatic cancer, and they might also be a promising "weapon" that can be used for anticancer treatments in humans. Even though the exact role of these stem cells in pancreatic cancer development and/or progression in humans still remains unclear, this concept continues to drive a completely novel scientific avenue in pancreatic cancer research and gives rise to innovative ideas regarding novel therapeutic modalities that can be safely offered to patients.

Hepatocyte growth factor inhibition: a novel therapeutic approach in pancreatic cancer

BACKGROUND

Pancreatic stellate cells (PSCs, which produce the stroma of pancreatic cancer (PC)) interact with cancer cells to facilitate PC growth. A candidate growth factor pathway that may mediate this interaction is the HGF-c-MET pathway.

METHODS

Effects of HGF inhibition (using a neutralising antibody AMG102) alone or in combination with gemcitabine were assessed (i) in vivo using an orthotopic model of PC, and (ii) in vitro using cultured PC cells (AsPC-1) and human PSCs.

RESULTS

We have shown that human PSCs (hPSCs) secrete HGF but do not express the receptor c-MET, which is present predominantly on cancer cells. HGF inhibition was as effective as standard chemotherapy in inhibiting local tumour growth but was significantly more effective than gemcitabine in reducing tumour angiogenesis and metastasis. HGF inhibition has resulted in reduced metastasis; however, interestingly this antimetastatic effect was lost when combined with gemcitabine. This suggests that gemcitabine treatment selects out a subpopulation of cancer cells with increased epithelial-mesenchymal transition (EMT) and stem-cell characteristics, as supported by our findings of increased expression of EMT and stem-cell markers in tumour sections from our animal model. In vitro studies showed that hPSC secretions induced proliferation and migration, but inhibited apoptosis, of cancer cells. These effects were countered by pretreatment of hPSC secretions with a HGF-neutralising antibody but not by gemcitabine, indicating a key role for HGF in PSC-PC interactions.

CONCLUSIONS

Our studies suggest that targeted therapy to inhibit stromal-tumour interactions mediated by the HGF-c-MET pathway may represent a novel therapeutic approach in PC that will require careful modelling for optimal integration with existing treatment modalities.

Differential expression of genes encoding proteins of the HGF/MET system in insulinomas

BACKGROUND

Insulinomas are the most common functional pancreatic neuroendocrine tumors, whereas histopathological features do not predict their biological behaviour. In an attempt to better understand the molecular processes involved in the tumorigenesis of islet beta cells, the present study evaluated the expression of genes belonging to the hepatocyte growth factor and its receptor (HGF/MET) system, namely, MET, HGF; HGFAC and ST14 (encode HGF activator and matriptase, respectively, two serine proteases that catalyze conversion of pro-HGF to active HGF); and SPINT1 and SPINT2 (encode serine peptidase inhibitors Kunitz type 1 and type 2, respectively, two inhibitors of HGF activator and of matriptase).

METHODS

Quantitative real-time reverse transcriptase polymerase chain reaction was employed to assess RNA expression of the target genes in 24 sporadic insulinomas: 15 grade 1 (G1), six grade 2 (G2) and three hepatic metastases. Somatic mutations of MET gene were searched by direct sequencing of exons 2, 10, 14, 16, 17 and 19.

RESULTS

Overexpression of MET was observed in the three hepatic metastases concomitantly with upregulation of the genes encoding HGF and matriptase and downregulation of SPINT1. A positive correlation was observed between MET RNA expression and Ki-67 proliferation index while a negative correlation was detected between SPINT1 expression and the mitotic index. No somatic mutations were found in MET gene.

CONCLUSION

The final effect of the increased expression of HGF, its activator (matriptase) and its specific receptor (MET) together with a decreased expression of one potent inhibitor of matriptase (SPINT1) is probably a contribution to tumoral progression and metastatization in insulinomas.

Hepatocyte Growth Factor from a Clinical Perspective: A Pancreatic Cancer Challenge

Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States and incidence rates are rising. Both detection and treatment options for pancreatic cancer are limited, providing a less than 5% five-year survival advantage. The need for new biomarkers for early detection and treatment of pancreatic cancer demands the efficient translation of bench knowledge to provide clinical benefit. One source of therapeutic resistance is the pancreatic tumor microenvironment, which is characterized by desmoplasia and hypoxia making it less conducive to current therapies. A major factor regulating desmoplasia and subsequently promoting chemoresistance in pancreatic cancer is hepatocyte growth factor (HGF), the sole ligand for c-MET (mesenchymal-epithelial transition), an epithelial tyrosine kinase receptor. Binding of HGF to c-MET leads to receptor dimerization and autophosphorylation resulting in the activation of multiple cellular processes that support cancer progression. Inhibiting activation of c-MET in cancer cells, in combination with other approaches for reducing desmoplasia in the tumor microenvironment, might significantly improve the success of chemotherapy. Therefore, HGF makes a potent novel target for developing therapeutic strategies in combination with existing drugs for treating pancreatic adenocarcinoma. This review provides a comprehensive analysis of HGF and its promising potential as a chemotherapeutic target for pancreatic cancer.

CXCL8, overexpressed in colorectal cancer, enhances the resistance of colorectal cancer cells to anoikis

Anoikis is a form of apoptosis which occurs when anchorage-dependent cells either show loss of adhesion or inappropriate adhesion. Only a few cancer cells that detach from the primary site of the tumor acquire the ability to resist anoikis and form metastasis. The mechanism underlying the resistance of colorectal cancer (CRC) cells to anoikis remains unclear. Interleukin-8 (alternatively known as CXCL8) is associated with CRC angiogenesis and progression. Here, we found that a high abundance of CXCL8 or TOPK strongly correlated with poor overall and disease-free survival of 186 patients with CRC. A combination of high CXCL8 and high TOPK expressions had the worst prognosis. We showed that CXCL8 expression was negatively correlated with anoikis in CRC cells. CXCL8 treatment enhanced the resistance of CRC cells to apoptosis, which was accompanied by the increase of TOPK, and the activation of AKT and ERK. Moreover, we demonstrated that the inhibition of either ERK or AKT by specific chemical inhibitors attenuated the CXCL8-mediated resistance to anoikis. Treatment with AKT inhibitor abolished the effects of CXCL8 on TOPK expression, suggesting that TOPK was downstream of AKT in the process of anoikis. Taken together, we demonstrated that CXCL8 is strongly implicated in the resistance of CRC cells to anoikis, and that the AKT, TOPK and ERK pathway may be a potential therapeutic target for CRC.

Met receptor-induced Grb2 or Shc signals both promote transformation of intestinal epithelial cells, albeit they are required for distinct oncogenic functions

Background

Deregulation of receptor tyrosine kinases (RTK) contributes to the initiation and progression of intestinal-derived epithelial cancers, including colorectal cancer (CRC). However, the roles of the proximal signaling molecules engaged by RTKs in different oncogenic functions of CRC remain unclear.

Methods

Herein, the functional impact of expressing variant forms of the oncogenic Met receptor (Tpr-Met) that selectively recruit the adaptor proteins Grb2 or Shc was investigated in a model derived from normal intestinal epithelial cells (IEC-6). An RNA interference (RNAi) approach was used to define the requirement of Grb2 or Shc in Tpr-Met-transformed IEC-6 cells. Since Grb2 and Shc couple RTKs to the activation of the Ras/MEK/Erk and PI3K/Akt pathways, Erk and Akt phosphorylation/activation states were monitored in transformed IEC-6 cells, and a pharmacological approach was employed to provide insights into the roles of these pathways in oncogenic processes evoked by activated Met, and downstream of Grb2 and Shc.

Results

We show, for the first time, that constitutive activation of either Grb2 or Shc signals in IEC-6 cells, promotes morphological transformation associated with down-regulation of E-cadherin, as well as increased cell growth, loss of growth contact inhibition, anchorage-independent growth, and resistance to serum deprivation and anoikis. Oncogenic activation of Met was revealed to induce morphological transformation, E-cadherin down-regulation, and protection against anoikis by mechanisms dependent on Grb2, while Shc was shown to be partly required for enhanced cell growth. The coupling of activated Met to the Ras/MEK/Erk and PI3K/Akt pathways, and the sustained engagement of Grb2 or Shc in IECs, was shown to trigger negative feedback, limiting the extent of activation of these pathways. Nonetheless, morphological alterations and E-cadherin down-regulation induced by the oncogenic Tpr-Met, and by Grb2 or Shc signals, were blocked by MEK, but not PI3K, inhibitors while the enhanced growth and resistance to anoikis induced by Tpr-Met were nearly abolished by co-treatment with both inhibitors.

Conclusion

Overall, these results identify Grb2 and Shc as central signaling effectors of Met-driven progression of intestinal epithelial-derived cancers. Notably, they suggest that Grb2 may represent a promising target for the design of novel CRC therapies.

Anoikis resistance: an essential prerequisite for tumor metastasis

Metastasis is a multistep process including dissociation of cancer cells from primary sites, survival in the vascular system, and proliferation in distant target organs. As a barrier to metastasis, cells normally undergo an apoptotic process known as “anoikis,” a form of cell death due to loss of contact with the extracellular matrix or neighboring cells. Cancer cells acquire anoikis resistance to survive after detachment from the primary sites and travel through the circulatory and lymphatic systems to disseminate throughout the body. Because recent technological advances enable us to detect rare circulating tumor cells, which are anoikis resistant, currently, anoikis resistance becomes a hot topic in cancer research. Detailed molecular and functional analyses of anoikis resistant cells may provide insight into the biology of cancer metastasis and identify novel therapeutic targets for prevention of cancer dissemination. This paper comprehensively describes recent investigations of the molecular and cellular mechanisms underlying anoikis and anoikis resistance in relation to intrinsic and extrinsic death signaling, epithelial-mesenchymal transition, growth factor receptors, energy metabolism, reactive oxygen species, membrane microdomains, and lipid rafts.