Selective tumorigenesis in non-parenchymal liver epithelial cell lines by hepatocyte growth factor transfection

Therapeutic advances of targeting receptor tyrosine kinases in cancer

Receptor tyrosine kinases (RTKs), a category of transmembrane receptors, have gained significant clinical attention in oncology due to their central role in cancer pathogenesis. Genetic alterations, including mutations, amplifications, and overexpression of certain RTKs, are critical in creating environments conducive to tumor development. Following their discovery, extensive research has revealed how RTK dysregulation contributes to oncogenesis, with many cancer subtypes showing dependency on aberrant RTK signaling for their proliferation, survival and progression. These findings paved the way for targeted therapies that aim to inhibit crucial biological pathways in cancer. As a result, RTKs have emerged as primary targets in anticancer therapeutic development. Over the past two decades, this has led to the synthesis and clinical validation of numerous small molecule tyrosine kinase inhibitors (TKIs), now effectively utilized in treating various cancer types. In this manuscript we aim to provide a comprehensive understanding of the RTKs in the context of cancer. We explored the various alterations and overexpression of specific receptors across different malignancies, with special attention dedicated to the examination of current RTK inhibitors, highlighting their role as potential targeted therapies. By integrating the latest research findings and clinical evidence, we seek to elucidate the pivotal role of RTKs in cancer biology and the therapeutic efficacy of RTK inhibition with promising treatment outcomes.

To Investigate Growth Factor Receptor Targets and Generate Cancer Targeting Inhibitors

Receptor tyrosine kinase (RTK) regulates multiple pathways, including Mitogenactivated protein kinases (MAPKs), PI3/AKT, JAK/STAT pathway, etc. which has a significant role in the progression and metastasis of tumor. As RTK activation regulates numerous essential bodily processes, including cell proliferation and division, RTK dysregulation has been identified in many types of cancers. Targeting RTK is a significant challenge in cancer due to the abnormal upregulation and downregulation of RTK receptors subfamily EGFR, FGFR, PDGFR, VEGFR, and HGFR in the progression of cancer, which is governed by multiple RTK receptor signalling pathways and impacts treatment response and disease progression. In this review, an extensive focus has been carried out on the normal and abnormal signalling pathways of EGFR, FGFR, PDGFR, VEGFR, and HGFR and their association with cancer initiation and progression. These are explored as potential therapeutic cancer targets and therefore, the inhibitors were evaluated alone and merged with additional therapies in clinical trials aimed at combating global cancer.

ITGB1 Drives Hepatocellular Carcinoma Progression by Modulating Cell Cycle Process Through PXN/YWHAZ/AKT Pathways

Integrin β1 (ITGB1), which acts as an extracellular matrix (ECM) receptor, has gained increasing attention as a therapeutic target for the treatment of hepatocellular carcinoma (HCC). However, the underpinning mechanism of how ITGB1 drives HCC progression remains elusive. In this study, we first found that ITGB1 expression was significantly higher in HCC tissues than in normal controls by bioinformatics analysis. Furthermore, bioinformatics analysis revealed that paxillin (PXN) and 14-3-3 protein zeta (YWHAZ) are the molecules participating in ITGB1-regulated HCC tumor cell cycle progression. Indeed, immunohistochemistry (IHC) revealed that ITGB1, paxillin, and YWHAZ were strongly upregulated in paired HCC tissue compared with adjacent normal tissues. Notably, the inhibition of ITGB1 expression by small interfering RNA (siRNA) resulted in the downregulated expression of PXN and YWHAZ in primary HCC cells, as assessed by western blot and immunostaining. In addition, ITGB1 knockdown markedly impaired the aggressive behavior of HCC tumor cells and delayed cell cycle progression as determined by cell migration assay, drug-resistance analysis, colony formation assay, quantitative real-time polymerase chain reaction (qRT-PCR), and cell cycle analysis as well as cell viability measurements. More importantly, we proved that xenograft ITGB1^high tumors grew more rapidly than ITGB1^low tumors. Altogether, our study showed that the ITGB1/PXN/YWHAZ/protein kinase B (AKT) axis enhances HCC progression by accelerating the cell cycle process, which offers a promising approach to halt HCC tumor growth.

EGFR/c-Met and mTOR signaling are predictors of survival in non-small cell lung cancer

BACKGROUND

EGFR/c-Met activation/amplification and co-expression, mTOR upregulation/activation, and Akt/Wnt signaling upregulation have been individually associated with more aggressive disease and characterized as potential prognostic markers for lung cancer patients.

METHODS

Tumors obtained from 109 participants with stage I-IV non-small cell lung cancer (NSCLC) were studied for EGFR/c-Met co-localization as well as for total and active forms of EGFR, c-Met, mTOR, S6K, beta-catenin, and Axin2. Slides were graded by two independent blinded pathologists using a validated scoring system. Protein expression profile correlations were assessed using Pearson correlation and Spearman's rho. Prognosis was assessed using Kaplan-Meier analysis.

RESULTS

Protein expression profile analysis revealed significant correlations between EGFR/p-EGFR (p = 0.0412) and p-mTOR/S6K (p = 0.0044). Co-localization of p-EGFR/p-c-Met was associated with increased p-mTOR (p = 0.0006), S6K (p = 0.0018), and p-S6K (p < 0.0001) expression. In contrast, active beta-catenin was not positively correlated with EGFR/c-Met nor any activated proteins. Axin2, a negative regulator of the Wnt pathway, was correlated with EGFR, p-EGFR, p-mTOR, p-S6K, EGFR/c-Met co-localization, and p-EGFR/p-c-Met co-localization (all p-values <0.03). Kaplan-Meier analysis revealed shorter median survival in participants with high expression of Axin2, total beta-catenin, total/p-S6K, total/p-mTOR, EGFR, and EGFR/c-Met co-localization compared with low expression. After controlling for stage of disease at diagnosis, subjects with late-stage disease demonstrated shorter median survival when exhibiting high co-expression of EGFR/c-Met (8.1 month versus 22.3 month, p = 0.050), mTOR (6.7 month versus 22.3 month, p = 0.002), and p-mTOR (8.1 month versus 25.4 month, p = 0.004) compared with low levels.

CONCLUSIONS

These findings suggest that increased EGFR/c-Met signaling is correlated with upregulated mTOR/S6K signaling, which may in turn be associated with shorter median survival in late-stage NSCLC.

Identification of molecular targets in vulvar cancers

OBJECTIVES

To identify molecular alterations that contribute to vulvar cancer pathogenesis with the intent of identifying molecular targets for treatment.

METHODS

After retrospective analysis of a database of molecularly-profiled gynecologic cancer patients, 149 vulvar cancer patients were included and tested centrally at a CLIA laboratory (Caris Life Sciences, Phoenix, AZ). Tests included one or more of the following: gene sequencing (Sanger or next generation sequencing [NGS]), protein expression (immunohistochemistry [IHC]), and gene amplification (C/FISH). A Fisher's exact test was used when indicated with a p-value≤0.05 indicating significance.

RESULTS

Median age was 65. 85% had squamous cell carcinoma (SCC) and 15% adenocarcinoma (ADC) histologies. 46% had metastatic (Stage IV) disease. Targeted hot-spot sequencing identified variants in the following genes: TP53 (33%), PIK3CA/BRCA2 (8%, 10%, respectively), HRAS/FBXW7 (5%, 4%, respectively) and ERBB4/GNAS (3%, 3% respectively). Mutations in AKT1, ATM, FGFR2, KRAS, NRAS (n=1, respectively) and BRAF (n=2) also occurred. Specific protein changes for targetable genes included clinically pathogenic mutations commonly found in other cancers (e.g. PIK3CA: exon 9 [E545K], RAS: G13D, Q61L, BRCA2: S1667X, BRAF: R443T, FBXW7: E471fs, etc.). Drug targets identified by IHC and ISH methodologies include cMET (32% IHC, 2% ISH), PDL1 (18%), PTEN loss (56%), HER2 (4% IHC, 2% ISH) and hormone receptors (AR, 4%; ER, 11%; PR, 4%). Comparisons between SCC and ADC identified differential rates for AR, ER, HER2 and GNAS with an increased presence in ADC (p-values all <0.05).

CONCLUSIONS

Molecularly-guided precision medicine could provide vulvar cancer patients alternative, targeted treatment options.

Heterogeneous Stromal Signaling within the Tumor Microenvironment Controls the Metastasis of Pancreatic Cancer

Understanding how stromal signals regulate the development of pancreatic ductal adenocarcinoma (PDAC) may suggest novel therapeutic interventions in this disease. In this study, we assessed the metastatic role of stromal signals suggested to be important in the PDAC microenvironment. Src and IGF-1R phosphorylated the prometastatic molecule Annexin A2 (AnxA2) at Y23 and Y333 in response to stromal signals HGF and IGF-1, respectively, and IGF-1 expression was regulated by the Sonic Hedgehog (Shh) pathway. Both Shh and HGF were heterogeneously expressed in PDAC stroma, and only dual inhibition of these pathways could significantly suppress AnxA2 phosphorylation, PDAC growth, and metastasis. Taken together, our results illuminate tumor-stromal interactions, which drive metastasis, and provide a mechanism-based rationale for a stroma-directed therapy for PDAC. Cancer Res; 77(1); 41-52. ©2016 AACR.

Hepatocyte growth factor and the Met system as a mediator of tumor-stromal interactions

Crosstalk between carcinoma cells and host stromal cells such as fibroblasts has a great deal of influence on the invasive and metastatic behavior of cancer cells. The oncogenic action of fibroblasts has been demonstrated through genetic alterations that occur specifically in fibroblasts. Hepatocyte growth factor (HGF), a ligand for the Met receptor tyrosine kinase, plays a definitive role, particularly in the progression to invasive and metastatic cancers, predominantly as a stroma-derived paracrine mediator. Many types of cancer cells secrete molecules that enhance HGF production in fibroblasts, while fibroblast-derived HGF, in turn, is a potent stimulator of the invasion of cancer cells. Fibroblast-specific genetic alterations leading to an overexpression of HGF are associated with the development of epithelial neoplasia and invasive carcinoma. Strategies for targeting the HGF-Met axis are being pursued, in attempts to block the malignant behavior of cancers. In normal tissues, the HGF-Met axis plays diverse roles in organogenesis and in wound healing. The simile that "cancer is a never-healing wound" appears to be pertinent here.

Hepatocyte growth factor/c-met signaling in regulating urokinase plasminogen activator in human stomach cancer: A potential therapeutic target for human stomach cancer

BACKGROUND

Up-regulation of the hepatocyte growth factor (HGF), its transmembrane tyrosine kinase receptor (c-Met), and urokinase type plasminogen activator (uPA), is associated with the development and metastasis of various types of cancers. However, the mechanisms by which HGF/c-Met signaling mediates cancer progression and metastasis are unclear.

METHODS

We investigated the roles of HGF/c-Met in tumor progression and metastasis in NUGC-3 and MKN-28 stomach cancer cell lines.

RESULTS

Treatment with HGF increased c-Met phosphorylation in a dose-dependent manner, as well as increasing cell proliferation. HGF treatment also increased the protein level and the activity of uPA in NUGC-3 and MKN-28 cells. A monoclonal antibody against human uPA receptor (uPAR), mAb 3936, inhibited HGF-mediated tumor cell invasion in a dose-dependent manner. Down-regulation of uPA using uPA-shRNA induced a decrease in in vitro cell invasion in NUGC-3 cells.

CONCLUSIONS

These results suggest that NUGC-3 and MKN-28 cells express functional c-Met, which may provide a therapeutic target for interfering with metastases of cancer cells by inhibiting uPA and uPAR-mediated proteolysis.

Augmented fumonisin B1 toxicity in co-cultures: evidence for crosstalk between macrophages and non-parenchymatous liver epithelial cells involving proinflammatory cytokines

Fumonisin B1, a common mycotoxin produced by Fusarium verticillioides found in corn, causes several fatal animal diseases. Liver and kidney are target organs of fumonisin B1 in laboratory animals, but primary rodent hepatocytes and liver slices were resistant to fumonisin B1-induced cytotoxic effects. We have shown that fumonisin B1 induces expression of tumor necrosis factor (TNF)alpha, interferon (IFN)gamma, and interleukine (IL) 12, in mouse liver. In various models of acute liver injury, a positive amplification loop involving TNFalpha, IFNgamma, and IL-12 has been implied that involves Kupffer cells (macrophages), hepatic lymphocytes and non-parenchymatous liver epithelial cells (NPECs). In the current study, cellular interactions in fumonisin B1-induced toxicity were investigated, using co-cultures of murine macrophages (J774A.1) and NPECs (NMuLi). Treatment of the co-cultures with fumonisin B1-produced cytotoxicity, whereas either J774A.1 or NMuLi cultures alone showed no response to the mycotoxin. Accumulation of sphinganine occurred to the similar extent in individual cultures as well as co-cultures. Expression of TNFalpha and IL-12 was increased in co-cultures but not in individual cultures. Transfer of conditioned medium from fumonisin B1-treated J774A.1 cells to NMuLi cultures produced an increase in IFNgamma expression in NMuLi cells. Results indicated that macrophages and liver epithelial cells interact in response to fumonisin B1 and potentiate the cytokines expression, which may have implications in making hepatocytes responsive to cytotoxicity of fumonisin B1.

NK4 (HGF-antagonist/angiogenesis inhibitor) in cancer biology and therapeutics

Invasion and subsequent establishment of metastasis are devastating events for patients with cancer, but past therapeutic approaches have paid relatively little attention to these important issues. Hepatocyte growth factor (HGF) and its receptor, the c-Met tyrosine kinase, play roles in cancer invasion and metastasis in a wide variety of tumor cells. Activation of the c-Met receptor integrates multiple signal transduction pathways involved in cell-cell and cell-matrix interactions, cellular migration, and breakdown of the extracellular scaffold. Paracrine activation of the c-Met receptor by stromal-derived HGF mediates tumor-stromal interactions that facilitate invasion and metastasis. Likewise, aberrant expression of the c-Met receptor and autocrine or mutational activation of c-Met receptor tyrosine kinase are closely associated with the progression of malignant tumors. Based on this background, NK4, a competitive antagonist of HGF-c-Met association was prepared so as to block cancer invasion and metastasis. NK4, an internal fragment of HGF, binds to but does not activate the c-Met receptor, thereby competitively antagonizing the biological activities of HGF. Unexpectedly, NK4 was subsequently shown to be an angiogenesis inhibitor as well, and this angioinhibitory activity is independent of its action as an HGF-antagonist. Importantly, NK4 protein or NK4 gene therapy have been shown to inhibit tumor invasion, metastasis and angiogenesis, effectively converting malignant tumors into benign tumors. Targeting tumor invasion-metastasis and angiogenesis with NK4 seems to have considerable therapeutic potential for cancer patients.

High expression of Met/hepatocyte growth factor receptor suppresses tumorigenicity in NCI-H1264 lung carcinoma cells

The protein product of c-met proto-oncogene, Met, is a tyrosine kinase receptor for the hepatocyte growth factor (HGF). Met receptor is expressed in normal human bronchial epithelium. In comparison, its expression in squamous cell carcinoma (SQCC) of the lung is markedly decreased in a great majority of cases. To understand further the role of Met receptor overexpression in non-small-cell lung carcinoma, we forced-expressed the full-length met cDNA in the NCI-H1264 (H1264) lung carcinoma cell line with low constitutive expression of this receptor. In vitro studies demonstrated that increased Met expression in H1264 cells resulted in strong inhibition of their ability to form soft agar colonies and in marked suppression of tumorigenicity in the subcutaneous tissue of immune-deficient mice. This is despite inconsistent alteration in the proliferation rate on plastic surfaces. Tumor cells explanted from occasional xenograft tumors formed by the Met-overexpressing H1264 cells also demonstrated marked down-regulation of the receptor protein levels as compared to the transplanted cells. The results suggest that constitutive overexpression of Met receptor may negatively regulate the malignancy of certain human lung cancer cells.

Hepatocyte growth factor in renal failure: promise and reality

Can science discover some secrets of Greek mythology? In the case of Prometheus, we can now suppose that his amazing hepatic regeneration was caused by a peptide growth factor called hepatocyte growth factor (HGF). Increasing evidence indicates that HGF acts as a multifunctional cytokine on different cell types. This review addresses the molecular mechanisms that are responsible for the pleiotropic effects of HGF. HGF binds with high affinity to its specific tyrosine kinase receptor c-met, thereby stimulating not only cell proliferation and differentiation, but also cell migration and tumorigenesis. The three fundamental principles of medicine-prevention, diagnosis, and therapy-may be benefited by the rational use of HGF. In renal tubular cells, HGF induces mitogenic and morphogenetic responses. In animal models of toxic or ischemic acute renal failure, HGF acts in a renotropic and nephroprotective manner. HGF expression is rapidly up-regulated in the remnant kidney of nephrectomized rats, inducing compensatory growth. In a mouse model of chronic renal disease, HGF inhibits the progression of tubulointerstitial fibrosis and kidney dysfunction. Increased HGF mRNA transcripts were detected in mesenchymal and tubular epithelial cells of rejecting kidney. In transplanted patients, elevated HGF levels may indicate renal rejection. When HGF is considered as a therapeutic agent in human medicine, for example, to stimulate kidney regeneration after acute injury, strategies need to be developed to stimulate cell regeneration and differentiation without an induction of tumorigenesis.

The five amino acid-deleted isoform of hepatocyte growth factor promotes carcinogenesis in transgenic mice

Hepatocyte growth factor (HGF) is a polypeptide with mitogenic, motogenic, and morphogenic effects on different cell types including hepatocytes. HGF is expressed as two biologically active isotypes resulting from alternative RNA splicing. The roles of each HGF isoform in development, liver regeneration and tumorigenesis have not yet been well characterized. We report the generation and analysis of transgenic mice overexpressing the five amino acid-deleted variant of HGF (dHGF) in the liver by virtue of an albumin expression vector. These ALB-dHGF transgenic mice develop normally, have an enhanced rate of liver regeneration after partial hepatectomy, and exhibit a threefold higher incidence of hepatocellular carcinoma (HCC) beyond 17 months of age. Moreover, overexpression of dHGF dramatically accelerates diethyl-nitrosamine induced HCC tumorigenesis. These tumors arise faster, are significantly larger, more numerous and more invasive than those appearing in non-transgenic littermates. Approximately 90% of female dHGF-transgenic mice had multiple macroscopic HCCs 40 weeks after injection of DEN; whereas the non-transgenic counterparts had only microscopic nodules. Liver tumors and cultured tumor cell lines from dHGF transgenics showed high levels of HGF and c-Met mRNA and protein. Together, these results reveal that in vivo dHGF plays an active role in liver regeneration and HCC tumorigenesis.

Establishment of a functional HGF/C-MET autocrine loop in spontaneous transformants of WB-F344 rat liver stem-like cells

A model of spontaneous malignant transformation was used to evaluate the molecular changes that take place in WB-F344 rat liver epithelial cells during neoplastic transformation and tumorigenesis. A comparison of wild-type low-passage WB-F344 cells to spontaneously transformed tumor cell lines revealed that the majority of the tumor cell lines have an increased capacity for autonomous proliferation and motility when maintained in serum-free media. In the current study, we show that c-met is expressed at some level in wild-type WB-F344 cells and in all of the spontaneously transformed tumor cell lines, and that 9/16 of the tumor cell lines have acquired hepatocyte growth factor (HGF) expression. In vitro growth of HGF-expressing tumor cell lines is inhibited as much as 68% by the addition of neutralizing antibodies to HGF or antisense HGF oligonucleotides, indicating that the production of HGF by the tumor cells is partially responsible for driving autonomous proliferation in a subset of tumor cell lines. Furthermore, conditioned media collected from HGF-expressing tumor cell lines stimulates DNA synthesis in wild-type WB-F344 cells, and this effect can be abrogated by pre-incubation of the conditioned media with neutralizing antibodies to HGF. Because HGF is a motility-promoting growth factor, all cell lines were evaluated to determine if expression of HGF stimulated motogenesis. All tumor cell lines (regardless of HGF expression) were highly motile in comparison with wild-type WB-F344 cells, with a 3.5-fold to 20-fold greater number of motile cells. The high basal rate of motility characteristic of the tumor cell lines is not a result of the production of HGF, because it is also a property of the cell lines that do not express HGF messenger RNA. Furthermore, tumor cell motility is not inhibited by antisense oligonucleotides or neutralizing antibodies. Establishment of an autocrine HGF/c-met loop in a subset of spontaneously transformed WB-F344 cell lines may influence development and/or expression of the tumorigenic phenotype by driving cellular proliferation.