Anaplastic lymphoma kinase protein expression predicts micrometastases and prognosis for patients with hepatocellular carcinoma

Clinical-Pathological Evaluation and Prognostic Analysis of 228 Merkel Cell Carcinomas Focusing on Tumor-Infiltrating Lymphocytes, MCPYV Infection and ALK Expression

Merkel cell carcinoma is a rare and aggressive primary neuroendocrine carcinoma of the skin, whose pathogenesis can be traced back to UV radiation damage or Merkel cell polyomavirus (MCPyV) infection. Despite some improvements on the characterization of the disease partly due to its increased incidence, crucial pathogenetic and prognostic factors still need to be refined. A consecutive series of 228 MCC from three hospitals in Turin was collected with the aim of both analyzing the apparent increase in MCC incidence in our area and investigating the distribution and prognostic role of clinical-pathological parameters, with a focus on MCPyV status, ALK tumor expression and tumor infiltrating lymphocytes (TILs). Review of morphology and conventional immunohistochemical staining was possible in 191 cases. In 50 cases, the expression of the novel neuroendocrine marker INSM1 was additionally assessed. Fourteen cases of MCC of unknown primary skin lesion were identified and separately analyzed. While confirming an exponential trend in MCC incidence in the last decades and providing a description of histological and cytological features of a large series of MCC, the present study concludes that 1) INSM1 is a highly sensitive marker in both skin and lymph node primary MCC; 2) positive MCPyV status, brisk TILs and lower tumor size and thickness are independent positive prognostic parameters, and the combination of the former two may provide a novel tool for prognostic stratification; 3) ALK is expressed 87% of MCC and associated with positive viral status, and could represent a prognostic biomarker, if validated in larger series.

ALK is frequently phosphorylated in Merkel cell carcinoma and associates with longer survival

Merkel cell carcinoma (MCC) is a rare skin cancer with only limited therapeutic options for advanced disease. We previously showed that oncogene ALK is frequently expressed at the RNA level in MCC and further that ALK positivity by immunohistochemistry is frequent and correlates strongly with Merkel cell polyomavirus (MCPyV) positivity. In this study, we investigated whether ALK receptor is active in MCC tumor samples and MCC cell lines, and whether ALK would be a prospective treatment target in MCC. We utilized tissue microarrays constructed from 136 primary MCC tumor samples as well as nine previously established MCC cell lines to determine the presence of ALK and phosphorylated ALK (p-ALK) via immunohistochemistry. Almost half of the analyzed MCC tumors displayed ALK phosphorylation (47.8%). Analysis of MCC tumor samples revealed that the presence of p-ALK correlated to MCPyV positivity, younger age, nonexistence of metastases at diagnosis and ultimately to better MCC-specific survival. In contrast to MCC tumor samples only two out of nine MCC cell lines showed only low ALK phosphorylation by immunohistochemistry. Our study reveals clear disparity in ALK activity between patient derived tumors and cell line samples and therefore, more advanced disease models such as xenografts are necessary to resolve whether ALK is a useful treatment target in MCC.

Inhibition of anaplastic lymphoma kinase promotes apoptosis and suppresses proliferation in human hepatocellular carcinoma

Our study was to examine the roles of crizotinib and ceritinib in hepatocellular carcinoma (HCC) cells and explore the possible mechanisms. MTT assay was employed to examine the proliferation of five HCC cell lines treated with various concentrations of crizotinib or ceritinib. HepG2 and HCCLM3 cells were incubated with 2 nmol/l ceritinib for 1 week, followed by crystal violet staining and cell counting. Protein amounts of t-ALK, p-ALK, t-AKT, p-AKT, t-ERK, p-ERK, Mcl-1, survivin, and XIAP in HepG2 cells under different culture conditions were evaluated by western blot. HepG2 and HCCLM3 cells were treated with vehicle or ceritinib and measured by flow cytometry apoptosis analysis with Annexin-V/propidium iodide staining. MTT assay showed that both crizotinib and ceritinib suppressed the proliferation of various human HCC cells. Crystal violet staining analysis also indicated that ceritinib effectively inhibited human HCC cell proliferation. Western blot analysis indicated that both crizotinib and ceritinib inhibited ALK, AKT, and ERK phosphorylations. In addition, ceritinib reduced antiapoptotic gene expressions in HepG2 cells. Flow cytometry analysis indicated that ceritinib induced HepG2 and HCCLM3 cells apoptosis. ALK inhibitor exhibited antitumor effects by inhibiting ALK activation, repressing AKT and ERK pathways, and suppressing antiapoptotic gene expressions, which subsequently promoted apoptosis and suppressed HCC cell proliferations.

ALK and EGFR expression by immunohistochemistry are associated with Merkel cell polyomavirus status in Merkel cell carcinoma

AIMS

Merkel cell carcinoma, a rare cutaneous neuroendocrine tumour of the skin, can be categorised into two groups according to Merkel cell polyomavirus (MCV) presence. MCV-negative tumours are more aggressive and frequently associated with gene mutations. Some of the genes are potential therapeutic targets. We have previously reported EGFR mutations in six of 27 MCC tumours and overexpression of ALK and EZH2 at mRNA level in MCC tumours. In this study, we sought to determine expression of ALK, EGFR and EZH2 in MCC samples and assess their correlation to MCV status and clinical parameters.

METHODS AND RESULTS

Tissue microarrays were utilised and stained with primary antibodies. Staining data were statistically compared to patient sex, tumour location and development of metastasis and MCC-specific death; 112 tumours and their corresponding patient data were included. We found strong expression of ALK in 51% and strong expression of EZH2 in 76% of the tumours. There was evident correlation of ALK expression with MCV-positivity. Expression of EGFR was infrequent, presenting only in seven MCV-negative tumours. None of the proteins associated with development of metastasis or MCC specific death.

CONCLUSIONS

ALK and EZH2 expression are frequent in MCC and ALK expression correlates to MCV positivity. EGFR positive tumours might respond to EGFR inhibiting treatment.

Systematic analysis of NLMP suggests nuclear localization of RTK/MET kinases resemble cancer cell clearance

BACKGROUND

Some membrane proteins can translocate into the nucleus, defined as nuclear localized membrane proteins (NLMPs), including receptor tyrosine kinases (RTKs). We previously showed that nuclear MET (nMET), a member of RTKs, mediates cancer stem-like cells self-renewal to promote cancer recurrence. However, it is unknown that nMET or mMET, which is the ancestor in the evolution of cancer cell survival and clearance. Here, we aim to study the NLMP functions in cell death, differentiation and survival.

METHOD

We applied the systematic reanalysis of functional NLMP and clinical investigations of nMET from databases. In addition, we used soft agar assay, immunoblotting, flow cytometry, and immunofluorescence confocal microscopy for examinations of nMET functions including stem-like cell formation, cell signaling, cell cycle regulation, and co-localization with regulators of cell signaling. ShRNA, antibody of recognizing surface membrane MET based treatment were used to downregulate endogenous nMET to uncover its function.

RESULTS

We predicted and demonstrated that nMET and nEGFR are most likely not ancestors. nMET overexpression induces both cell death and survival with drug resistance and stem cell-like characters. Moreover, the paradoxical function of nMET in both cell death and cell survival is explained by the fact that nMET induces stem cell-like cell growth, DNA damage repair, to evade the drug sensitization for survival of single cells while non-stem cell-like nMET expressing single cells may undergo clearance by cell death through cell cycle arrest induced by p21.

CONCLUSION

Taken together, our data suggest a link between nuclear RTK and cancer cell evolutionary clearance via cell death, and drug resistance for survival through stemness selection. Targeting evolved nuclear RTKs in cancer stem cells would be a novel avenue for precision cancer therapy.

Inhibition of insulin-like growth factor 1 receptor enhances the efficacy of sorafenib in inhibiting hepatocellular carcinoma cell growth and survival

Hepatocellular carcinoma (HCC) is the fifth most common primary cancer and second largest cause of cancer-related death worldwide. The first-line oral chemotherapeutic agent sorafenib only increases survival in patients with advanced HCC by less than 3 months. Most patients with advanced HCC have shown limited response rates and survival benefits with sorafenib. Although sorafenib is an inhibitor of multiple kinases, including serine/threonine-protein kinase c-Raf, serine/threonine-protein kinase B-Raf, vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, VEGFR-3, and platelet-derived growth factor receptor β, HCC cells are able to escape from sorafenib treatment using other pathways that the drug insufficiently inhibits. The aim of this study was to identify and target survival and proliferation pathways that enable HCC to escape the antitumor activity of sorafenib. We found that insulin-like growth factor 1 receptor (IGF1R) remains activated in HCC cells treated with sorafenib. Knockdown of IGF1R sensitizes HCC cells to sorafenib treatment and decreases protein kinase B (AKT) activation. Overexpression of constitutively activated AKT reverses the effect of knockdown of IGF1R in sensitizing HCC cells to treatment with sorafenib. Further, we found that ceritinib, a drug approved by the U.S. Food and Drug Administration for treatment of non-small cell lung cancer, effectively inhibits the IGF1R/AKT pathway and enhances the inhibitory efficacy of sorafenib in human HCC cell growth and survival in vitro, in a xenograft mouse model and in the c-Met/β-catenin-driven HCC mouse model. Conclusion: Our study provides a biochemical basis for evaluation of a new combination treatment that includes IGF1R inhibitors, such as ceritinib and sorafenib, in patients with HCC. (Hepatology Communications 2018;2:732-746).

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.

Aberrant expression of ALK and EZH2 in Merkel cell carcinoma

BACKGROUND

Distinct characteristic features categorize Merkel cell carcinoma (MCC) into two subgroups according to the Merkel cell polyomavirus infection. Many mutational studies on MCC have been carried out in recent years without identifying a prominent driver mutation. However, there is paucity reporting the expression of cancer genes at the RNA level in MCC tumors. In this study, we studied the RNA expression profiles of 26 MCC tumors, with a goal to identify prospective molecular targets that could improve the treatment strategies of MCC.

METHODS

RNA expression of 50 cancer-related genes in 26 MCC tumors was analyzed by targeted amplicon based next-generation sequencing using the Ion Torrent technology and the expression compared with that of normal, non-cancerous skin samples. Sequencing data were processed using Torrent Suite™ Software. Expression profiles of MCV-negative and MCV-positive tumors were compared. Fluorescence in situ hybridization was performed to study ALK rearrangements and immunohistochemistry to study ALK expression in tumor tissue.

RESULTS

ALK, CDKN2A, EZH2 and ERBB4 were overexpressed, and EGFR, ERBB2, PDGFRA and FGFR1 were underexpressed in MCC tumors compared to normal skin. In the MCV-negative tumors, MET, NOTCH1, FGFR3, and SMO were overexpressed and JAK3 and NPM1 were under-expressed compared to the MCV-positive tumors.

CONCLUSIONS

High expression of ALK, CDKN2A and EZH2 was recorded in MCC tumors. No ALK fusion was seen by FISH analysis. Overexpression of EZH2 suggests its potential as a drug target in MCC.