Progress in cancer therapy targeting c-Met signaling pathway

In-vitro Evaluation of Triazine Scaffold for Anticancer Drug Development: A Review

INTRODUCTION

The widespread importance of the synthesis and modification of anticancer agents has given rise to many numbers of medicinal chemistry programs. In this regard, triazine derivatives have attracted attention due to their remarkable activity against a wide range of cancer cells. This evaluation covers work reports to define the anticancer activity, the most active synthesized compound for the target, the SAR and, when described, the probable MOA besides similarly considered to deliver complete and target-pointed data for the development of types of anti-tumour medicines of triazine derivatives. Triazine scaffold for the development of anticancer analogues. Triazine can also relate to numerous beneficial targets, and their analogues have auspicious in-vitro and in-vivo anti-tumour activity. Fused molecules can improve efficacy, and drug resistance and diminish side effects, and numerous hybrid molecules are beneath diverse stages of clinical trials, so hybrid derivatives of triazine may offer valuable therapeutic involvement for the dealing of tumours.

OBJECTIVE

The objective of the recent review was to summarize the recent reports on triazine as well as its analogues with respect to its anticancer therapeutic potential.

CONCLUSION

The content of the review would be helpful to update the researchers working towards the synthesis and designing of new molecules for the treatment of various types of cancer disease with the recent molecules that have been produced from the triazine scaffold. Triazine scaffolds based on 1,3,5-triazine considerably boost molecular diversity levels and enable covering chemical space in key medicinal chemistry fields.

Polypharmacology-based kinome screen identifies new regulators of KSHV reactivation

Kaposi's sarcoma-associated herpesvirus (KSHV) causes several human diseases including Kaposi's sarcoma (KS), a leading cause of cancer in Africa and in patients with AIDS. KS tumor cells harbor KSHV predominantly in a latent form, while typically <5% contain lytic replicating virus. Because both latent and lytic stages likely contribute to cancer initiation and progression, continued dissection of host regulators of this biological switch will provide insights into fundamental pathways controlling the KSHV life cycle and related disease pathogenesis. Several cellular protein kinases have been reported to promote or restrict KSHV reactivation, but our knowledge of these signaling mediators and pathways is incomplete. We employed a polypharmacology-based kinome screen to identify specific kinases that regulate KSHV reactivation. Those identified by the screen and validated by knockdown experiments included several kinases that enhance lytic reactivation: ERBB2 (HER2 or neu), ERBB3 (HER3), ERBB4 (HER4), MKNK2 (MNK2), ITK, TEC, and DSTYK (RIPK5). Conversely, ERBB1 (EGFR1 or HER1), MKNK1 (MNK1) and FRK (PTK5) were found to promote the maintenance of latency. Mechanistic characterization of ERBB2 pro-lytic functions revealed a signaling connection between ERBB2 and the activation of CREB1, a transcription factor that drives KSHV lytic gene expression. These studies provided a proof-of-principle application of a polypharmacology-based kinome screen for the study of KSHV reactivation and enabled the discovery of both kinase inhibitors and specific kinases that regulate the KSHV latent-to-lytic replication switch.

Design, synthesis and biological evaluation of 4-(4-aminophenoxy)picolinamide derivatives as potential antitumor agents

Cancer is a leading cause of death in humans. Molecular targeted therapy for cancer has become a research hotspot as it is associated with low toxicity and high efficiency. In this study, a total of 36 derivatives of 4-(4-aminophenoxy)pyridinamide were designed and synthesized, based on the analysis of the binding patterns of cabozantinib and BMS-777607 to MET protein. Most target compounds exhibited moderate to excellent antiproliferative activity against three different cell lines (A549, HeLa and MCF-7). A total of 7 compounds had stronger inhibitory activities than cabozantinib, and the IC₅₀ value of the most promising compound 46 was 0.26 μM against the A549 cells, which was 2.4 times more active than that of cabozantinib. The structure-activity relationship of the target compounds was analyzed and summarized, and the action mechanism was discussed. The acridine orange (AO) staining assay and cell cycle apoptosis revealed that compound 46 dose-dependently induced apoptosis of A549 cells, and blocked the cells mainly in G0/G1 phase. The IC₅₀ value of compound 46 on c-Met kinase was 46.5 nM. Further docking studies and molecular dynamics simulations signaled that compound 46 formed four key hydrogen bonds to c-Met kinase, and these key amino acids played a major role in binding free energy. In addition, compound 46 also showed good pharmacokinetic characteristics in rats. In conclusion, compound 46 is a promising antitumor agent.

The Role of Genetic Polymorphisms in Differentiated Thyroid Cancer: A 2023 Update

Thyroid cancer is the most common endocrine malignancy, with an increasing trend in the past decades. It has a variety of different histological subtypes, the most frequent one being differentiated thyroid cancer, which refers to papillary carcinoma, the most common histological type, followed by follicular carcinoma. Associations between genetic polymorphisms and thyroid cancer have been investigated over the years and are an intriguing topic for the scientific world. To date, the results of associations of single nucleotide polymorphisms, the most common genetic variations in the genome, with thyroid cancer have been inconsistent, but many promising results could potentially influence future research toward developing new targeted therapies and new prognostic biomarkers, thus consolidating a more personalized management for these patients. This review focuses on emphasizing the existing literature data regarding genetic polymorphisms investigated for their potential association with differentiated thyroid cancer and highlights the opportunity of using genetic variations as biomarkers of diagnosis and prognosis for thyroid cancer patients.

Polypharmacology-based kinome screen identifies new regulators of KSHV reactivation

Kaposi's sarcoma-associated herpesvirus (KSHV) causes several human diseases including Kaposi's sarcoma (KS), a leading cause of cancer in Africa and in patients with AIDS. KS tumor cells harbor KSHV predominantly in a latent form, while typically <5% contain lytic replicating virus. Because both latent and lytic stages likely contribute to cancer initiation and progression, continued dissection of host regulators of this biological switch will provide insights into fundamental pathways controlling the KSHV life cycle and related disease pathogenesis. Several cellular protein kinases have been reported to promote or restrict KSHV reactivation, but our knowledge of these signaling mediators and pathways is incomplete. We employed a polypharmacology-based kinome screen to identifiy specific kinases that regulate KSHV reactivation. Those identified by the screen and validated by knockdown experiments included several kinases that enhance lytic reactivation: ERBB2 (HER2 or neu ), ERBB3 (HER3), ERBB4 (HER4), MKNK2 (MNK2), ITK, TEC, and DSTYK (RIPK5). Conversely, ERBB1 (EGFR1 or HER1), MKNK1 (MNK1) and FRK (PTK5) were found to promote the maintenance of latency. Mechanistic characterization of ERBB2 pro-lytic functions revealed a signaling connection between ERBB2 and the activation of CREB1, a transcription factor that drives KSHV lytic gene expression. These studies provided a proof-of-principle application of a polypharmacology-based kinome screen for the study of KSHV reactivation and enabled the discovery of both kinase inhibitors and specific kinases that regulate the KSHV latent-to-lytic replication switch.

Author Summary

Kaposi's sarcoma-associated herpesvirus (KSHV) causes Kaposi's sarcoma, a cancer particularly prevalent in Africa. In cancer cells, the virus persists in a quiescent form called latency, in which only a few viral genes are made. Periodically, the virus switches into an active replicative cycle in which most of the viral genes are made and new virus is produced. What controls the switch from latency to active replication is not well understood, but cellular kinases, enzymes that control many cellular processes, have been implicated. Using a cell culture model of KSHV reactivation along with an innovative screening method that probes the effects of many cellular kinases simultaneously, we identified drugs that significantly limit KSHV reactivation, as well as specific kinases that either enhance or restrict KSHV replicative cycle. Among these were the ERBB kinases which are known to regulate growth of cancer cells. Understanding how these and other kinases contribute to the switch leading to production of more infectious virus helps us understand the mediators and mechanisms of KSHV diseases. Additionally, because kinase inhibitors are proving to be effective for treating other diseases including some cancers, identifying ones that restrict KSHV replicative cycle may lead to new approaches to treating KSHV-related diseases.

Genomic Profiling of Metastatic Basal cell Carcinoma Reveals Candidate Drivers of Disease and Therapeutic Targets

Basal cell carcinomas (BCCs) are human beings' most common malignant tumors. Most are easily managed by surgery or topical therapies, and metastasis is rare. Although BCCs can become locally advanced, metastatic BCCs are very uncommon and may be biologically distinct. We assessed the clinicopathologic characteristics of 17 patients with metastatic BCC and pursued whole-exome sequencing of tumor and germline DNA from 8 patients. Genomic profiling revealed aberrant activation of Hedgehog signaling and alterations in GLI transcriptional regulators and Notch and Hippo signaling. Matched local recurrences of primary BCCs and metastases from 3 patients provided evidence of a clonal origin in all cases. Mutations associated with YAP inhibition were found exclusively in 2 hematogenously-spread lung metastases, and metastatic BCCs were enriched for mutations in the YAP/TAZ-binding domain of TEAD genes. Accordingly, YAP/TAZ nuclear localization was associated with metastatic types and Hippo mutations, suggesting an enhanced oncogenic role in hematogenously-spread metastases. Mutations in RET, HGF, and phosphatidylinositol 3‑kinase (PI3K)/protein kinase B (AKT) signaling were enriched compared with a cohort of low clinical-risk BCCs. Our results implicate Hippo and PI3K/AKT dysregulation in metastatic progression of BCCs, making these potential therapeutic targets in metastatic disease. The common clonal origin of matched recurrent and metastatic BCCs suggests that molecular profiling can assist in determining the nature/origin of poorly differentiated metastatic tumors of uncertain type. Genes and pathways enriched for mutations in this cohort are candidate drivers of metastasis and can be used to identify patients at high risk of metastasis who may benefit from aggressive local treatment and careful clinical follow-up.

Discovery of novel conjugates of quinoline and thiazolidinone urea as potential anti-colorectal cancer agent

Based on the obtained SARs, further structural optimisation of compound BC2021-104511-15i was conducted in this investigation, and totally ten novel quinoline derivates were designed, synthesised and optimised for biological activity. Among them, compound 10a displayed significant in vitro anticancer activity against COLO 205 cells with an IC₅₀ value of 0.11 μM which was over 90-fold more potent than that of Regorafenib (IC₅₀>10.0 μM) and Fruquintinib (IC₅₀>10.0 μM). Furthermore, compound 10a exhibited over 90-fold selectivity towards COLO 205 relative to human normal colorectal mucosa epithelial cell FHC cells. Flow cytometry study demonstrated that compound 10a could induce apoptosis in COLO 205 cells, however, it could not induce cell cycle arrest in COLO 205 cells. The results of preliminary kinase profile study showed that compound 10a was a potential HGFR and MST1R dual inhibitor, with IC₅₀ values of 0.11 μM and 0.045 μM, respectively.

Blockade of c-Met-Mediated Signaling Pathways by E7050 Suppresses Growth and Promotes Apoptosis in Multidrug-Resistant Human Uterine Sarcoma Cells

E7050 is a potent inhibitor of c-Met receptor tyrosine kinase and has potential for cancer therapy. However, the underlying molecular mechanism involved in the anti-cancer property of E7050 has not been fully elucidated. The main objective of this study was to investigate the anti-tumor activity of E7050 in multidrug-resistant human uterine sarcoma MES-SA/Dx5 cells in vitro and in vivo, and to define its mechanisms. Our results revealed that E7050 reduced cell viability of MES-SA/Dx5 cells, which was associated with the induction of apoptosis and S phase cell cycle arrest. Additionally, E7050 treatment significantly upregulated the expression of Bax, cleaved PARP, cleaved caspase-3, p21, p53 and cyclin D1, while it downregulated the expression of survivin and cyclin A. On the other hand, the mechanistic study demonstrated that E7050 inhibited the phosphorylation of c-Met, Src, Akt and p38 in HGF-stimulated MES-SA/Dx5 cells. Further in vivo experiments showed that treatment of athymic nude mice carrying MES-SA/Dx5 xenograft tumors with E7050 remarkably suppressed tumor growth. E7050 treatment also decreased the expression of Ki-67 and p-Met, and increased the expression of cleaved caspase-3 in MES-SA/Dx5 tumor sections. Therefore, E7050 is a promising drug that can be developed for the treatment of multidrug-resistant uterine sarcoma.

Cryo-electron Microscopic Analysis of Single-Pass Transmembrane Receptors

Single-pass transmembrane receptors (SPTMRs) represent a diverse group of integral membrane proteins that are involved in many essential cellular processes, including signal transduction, cell adhesion, and transmembrane transport of materials. Dysregulation of the SPTMRs is linked with many human diseases. Despite extensive efforts in past decades, the mechanisms of action of the SPTMRs remain incompletely understood. One major hurdle is the lack of structures of the full-length SPTMRs in different functional states. Such structural information is difficult to obtain by traditional structural biology methods such as X-ray crystallography and nuclear magnetic resonance (NMR). The recent rapid development of single-particle cryo-electron microscopy (cryo-EM) has led to an exponential surge in the number of high-resolution structures of integral membrane proteins, including SPTMRs. Cryo-EM structures of SPTMRs solved in the past few years have tremendously improved our understanding of how SPTMRs function. In this review, we will highlight these progresses in the structural studies of SPTMRs by single-particle cryo-EM, analyze important structural details of each protein involved, and discuss their implications on the underlying mechanisms. Finally, we also briefly discuss remaining challenges and exciting opportunities in the field.

Design, Synthesis, and Evaluation of New Mesenchymal–Epithelial Transition Factor (c-Met) Kinase Inhibitors with Dual Chiral Centers

A series of tepotinib derivatives with two chiral centers was designed, synthesized, and evaluated as anticancer agents. The optimal compound (R, S)-12a strongly exhibited antiproliferative activity against MHCC97H cell lines with an IC50 value of 0.002 μM, compared to tepotinib (IC50 = 0.013 μM). Mechanistic studies revealed that compound (R, S)-12a significantly inhibited c-Met activation, as well as the downstream AKT signaling pathway, and suppressed wound closure. Moreover, compound (R, S)-12a induced cellular apoptosis and cell cycle arrest at the G1 phase in a dose-dependent fashion.

Discovery of small-molecule fluorescent probes for C-Met

C-mesenchymal-epithelia transition factor (c-Met) is highly expressed in various solid tumors such as gastric cancer, liver cancer, and lung cancer, playing a pivotal role in the growth, maintenance, and development of different tumor cells. In this study, three small-molecule fluorescent probes (5, 11, 16) targeting c-Met were developed, and their design strategies were also initially explored. In general, the fluorescence properties of the probes themselves could meet the imaging requirements, and they have shown sufficient inhibitory activities against c-Met, especially probe 16, reflecting the targeting and acceptance. Also, fluorescence polarization assays and flow cytometry analysis verified the binding between the probes and c-Met. Cell imaging confirmed that these probes could be used to label c-Met on living cells. It is of positive significance for the development of c-Met kinase inhibitors and tumor pathology research.

Roles of MET in human cancer

The MET proto-oncogene was first identified in osteosarcoma cells exposed to carcinogens. Although expressed in many normal cells, MET is overexpressed in many human cancers. MET is involved in the initiation and development of various human cancers and mediates proliferation, migration and invasion. Accordingly, MET has been successfully used as a biomarker for diagnosis and prognosis, survival, post-operative recurrence, risk assessment and pathologic grading, as well as a therapeutic target. In addition, recent work indicates that inhibition of MET expression and function has potential clinical benefit. This review summarizes the role, mechanism, and clinical significance of MET in the formation and development of human cancer.

An updated patent review of small-molecule c-Met kinase inhibitors (2018-present)

INTRODUCTION

c-Met tyrosine kinase receptor is a high-affinity ligand of hepatocyte growth factor (HGF). c-Met is widely expressed in a variety of normal human tissues, but shows abnormally high expression, amplification or mutation in tumour tissues such as lung, gastric and breast cancers. Therefore, the use of c-Met as a target can achieve the inhibition of a series of abnormal physiological processes such as tumourigenesis, development and metastasis. A number of small molecule tyrosine kinase inhibitors targeting c-Met have been successfully marketed.

AREAS COVERED

This article reviews recent advances in patented c-Met small molecule inhibitors and their inhibitory activity against various cancer cells from 2018 to date.

EXPERT OPINION

To date, small molecule inhibitors targeting c-Met have demonstrated impressive therapeutic efficacy in the clinical setting. Most recent patents have focused on addressing the direction of c-Met amplification and overexpression. Despite the great success in the development of selective c-Met inhibitors, the effects of bypass secretion and mutagenesis have led to a need for new c-Met small molecule inhibitors that are safe, efficient, selective and less toxic with novel structures and effective against other targets.

Knockout of Hepatocyte Growth Factor by CRISPR/Cas9 System Induces Apoptosis in Hepatocellular Carcinoma Cells

Background: CRISPR/Cas9 system is a prokaryotic adaptive immune response system that uses noncoding RNAs to guide the Cas9 nuclease to induce site-specific DNA cleavage. Hepatocyte growth factor (HGF) is a well-known growth factor that plays a crucial role in cell growth and organ development. According to recent studies, it has been reported that HGF promoted growth of hepatocellular carcinoma (HCC) cells. Here, we investigated the apoptotic effects in HCC cells. Methods: Crispr-HGF plasmid was constructed using GeneArt CRISPR Nuclease Vector. pMex-HGF plasmid that targets HGF overexpressing gene were designed with pMex-neo plasmid. We performed real time-polymerase chain reaction to measure the expression of HGF mRNA. We performed cell counting assay and colony formation assay to evaluate cell proliferation. We also carried out migration assay and invasion assay to reveal the inhibitory effects of Crispr-HGF in HCC cells. Furthermore, we performed cell cycle analysis to detect transfection of Crispr-HGF induced cell cycle arrest. Collectively, we performed annexin V/PI staining assay and Western blot assay. Results: In Crispr-HGF-transfected group, the mRNA expression levels of HGF were markedly downregulated compared to pMex-HGF-transfected group. Moreover, Crispr-HGF inhibited cell viability in HCC cells. We detected that wound area and invaded cells were suppressed in Crispr-HGF-transfected cells. The results showed that transfection of Crispr-HGF induced cell cycle arrest and apoptosis in HCC cells. Expression of the phosphorylation of mitogen activated protein kinases and c-Met protein was regulated in Crispr-HGF-transfected group. Interestingly, we found that the expression of HGF protein in conditioned media significantly decreased in Crispr-HGF-transfected group. Conclusions: Taken together, we found that inhibition of HGF through transfection of Crispr-HGF suppressed cell proliferation and induced apoptotic effects in HCC Huh7 and Hep3B cells.

RTK Inhibitors in Melanoma: From Bench to Bedside

MAPK (mitogen activated protein kinase) and PI3K/AKT (Phosphatidylinositol-3-Kinase and Protein Kinase B) pathways play a key role in melanoma progression and metastasis that are regulated by receptor tyrosine kinases (RTKs). Although RTKs are mutated in a small percentage of melanomas, several receptors were found up regulated/altered in various stages of melanoma initiation, progression, or metastasis. Targeting RTKs remains a significant challenge in melanoma, due to their variable expression across different melanoma stages of progression and among melanoma subtypes that consequently affect response to treatment and disease progression. In this review, we discuss in details the activation mechanism of several key RTKs: type III: c-KIT (mast/stem cell growth factor receptor); type I: EGFR (Epidermal growth factor receptor); type VIII: HGFR (hepatocyte growth factor receptor); type V: VEGFR (Vascular endothelial growth factor), structure variants, the function of their structural domains, and their alteration and its association with melanoma initiation and progression. Furthermore, several RTK inhibitors targeting the same receptor were tested alone or in combination with other therapies, yielding variable responses among different melanoma groups. Here, we classified RTK inhibitors by families and summarized all tested drugs in melanoma indicating the rationale behind the use of these drugs in each melanoma subgroups from preclinical studies to clinical trials with a specific focus on their purpose of treatment, resulted effect, and outcomes.

Design, synthesis and antitumor evaluation of novel 5-methylpyrazolo[1,5-a]pyrimidine derivatives as potential c-Met inhibitors

A series of novel 5-methylpyrazolo[1,5-a]pyrimidine derivatives (10a-10x) were designed, synthesized, and evaluated for their in vitro inhibitory activities against c-Met kinase and antiproliferative activities against the SH-SY5Y, MDA-MB-231, A549, and HepG2 cell lines. Most of the compounds remarkably inhibited c-Met kinase and showed moderate to good cytotoxicity and selectivity toward the four cancer cell lines. Among them, compounds 10b and 10f were the two most potent selective c-Met inhibitors with half-maximal inhibitory concentration (IC₅₀) values of 5.17 ± 0.48 nM and 5.62 ± 0.78 nM, respectively, and suppression abilities comparable with the positive control cabozantinib. Cell proliferation assay further demonstrated that the two most promising compounds 10a and 10b also showed good cytotoxicity and selectivity toward MDA-MB-231 cells, with IC₅₀ values of 26.67 ± 2.56 μM and 26.83 ± 2.41 μM, respectively. Compounds 10f and 10g showed cytotoxicity and selectivity toward A549 cells, with IC₅₀ values of 20.20 ± 2.04 μM and 21.65 ± 1.58 μM, respectively. All antiproliferative activities were within the range of those of cabozantinib. Notably, these compounds presented relatively low hepatotoxicity compared with reference drugs. Moreover, the preliminary structure-activity relationship and docking studies revealed that replacement of a nitrogen-containing heterocycle on the R₂ (block A) group might improve the c-Met kinase inhibitory and antiproliferative effects in MDA-MB-231 cells, whereas displacement by a substituted benzene ring, especially for the p-fluorophenyl or 4-fluoro-3-methoxyphenyl moiety, on the R₂ group enhanced cytotoxicity toward A549 cells. Together, these results suggest that 10b and 10f are promising compounds and provide a basis for their development as new antitumor agents.

Inhibition of c-MET increases the antitumour activity of PARP inhibitors in gastric cancer models

Gastric cancer is the fifth most common malignancy and the third leading cause of cancer‐related death worldwide. Activation of c‐MET increases tumour cell survival through the initiation of the DNA damage repair pathway. PARP is an essential key in the DNA damage repair pathway. The primary role of PARP is to detect and initiate an immediate cellular response to single‐strand DNA breaks. Tumours suppressor genes such as BRCA1/2 are closely associated with the DNA repair pathway. In BRCA1/2 mutations or deficiency status, cells are more likely to develop additional genetic alterations and chromosomal instability and can lead to cancer. In this study, we investigate the role of c‐MET and PARP inhibition in a gastric cancer model. We exploited functional in vitro and in vivo experiments to assess the antitumour potential of co‐inhibition of c‐MET (SU11274) and PARP (NU1025). This leads to a reduction of gastric cancer cells viability, especially after knockdown of BRCA1/2 through apoptosis and induction of γ‐Η2ΑΧ. Moreover, in AGS xenograft models, the combinatorial treatment of NU1025 plus SU11274 reduced tumour growth and triggers apoptosis. Collectively, our data may represent a new therapeutic approach for GC thought co‐inhibition of c‐MET and PARP, especially for patients with BRCA1/2 deficiency tumours.

Identification of novel quinoline analogues bearing thiazolidinones as potent kinase inhibitors for the treatment of colorectal cancer

In this investigation, a novel series of quinoline analogues bearing thiazolidinones were designed and synthesized based on our previous study. Among them, the most potent compound 11k, 4-((4-(4-(3-(2-(2,6-difluorophenyl)-4-oxothiazolidin-3-yl)ureido)phenoxy)-6-methoxyquinolin-7-yl)oxy)-N-isopropylpiperidine-1-carboxamide, possessed submicromolar c-Met and Ron inhibitory activities. In addition, enzymatic assays against a mini-panel of kinases (c-Kit, B-Raf, c-Src, IGF1R, PDGFRα and AXL) were performed, the results showed that compound 11k exhibited moderate inhibitory activity against PDGFRα, c-Src and AXL. MTT assay revealed in vitro antitumor activities against HT-29 cells of compound 11k with an IC₅₀ value of 0.31 μM which was 9.3- and 34.2-fold more potent than that of Regorafenib (IC₅₀ = 2.87 μM) and Cabozantinib (IC₅₀ = 10.6 μM). Preliminary antitumor mechanisms were also investigated by cellular assays. Considerable cytotoxicity, antiproliferation and induction of apoptosis of compound 11k in a dose- and time-dependent manner were confirmed by IncuCyte live-cell imaging assays. Treatment with compound 11k caused slight G2-or M-phase arrest in HT-29 cells. Further cell selectivity of compound 11k showed that it was not active against human normal colorectal mucosa epithelial cell FHC at 10.0 μg/mL. The above results support further structural modification of compound 11k to improve its inhibitory activity, which will lead to more potent anticancer agents.

Effects of DSPP and MMP20 Silencing on Adhesion, Metastasis, Angiogenesis, and Epithelial-Mesenchymal Transition Proteins in Oral Squamous Cell Carcinoma Cells

Recent reports highlight the potential tumorigenic role of Dentin Sialophosphoprotein (DSPP) and its cognate partner Matrix Metalloproteinase 20 (MMP-20) in Oral Squamous Cell Carcinomas (OSCCs). However, the function/mechanism of these roles is yet to be fully established. The present study aimed to investigate the effects of DSPP and MMP20 silencing on specific proteins involved in oral cancer cell adhesion, angiogenesis, metastasis, and epithelial-mesenchymal transition (EMT). Stable lines of DSPP/MMP20 silenced OSCC cell line (OSC2), previously established via lentiviral-mediated shRNA transduction, were analyzed for the effects of DSPP, MMP20, and combined DSPP–MMP20 silencing on MMP2, MMP9, integrins αvβ3 and αvβ6, VEGF, Kallikerin- 4,-5,-8,-10, E-cadherin, N-cadherin, Vimentin, met, src, snail, and Twist by Western blot. Results show a significant decrease (p < 0.05) in the expression of MMP2, MMP9, integrin αvβ3, αvβ6, VEGF, Kallikerins -4, -5, -8, -10, N-cadherin, vimentin met, src, snail and twist following DSPP and MMP20 silencing, individually and in combination. On the other hand, the expression of E-cadherin was found to be significantly increased (p < 0.05). These results suggest that the tumorigenic effect of DSPP and MMP20 on OSC2 cells is mediated via the upregulation of the genes involved in invasion, metastasis, angiogenesis, and epithelial-mesenchymal transition (EMT).

Recurrence of ovarian squamous cell carcinoma with MET gene copy number variation: a case report and review of literature

Background

Malignant transformation such as ovarian squamous cell carcinoma (SCC) in ovarian mature cystic teratoma (OMCT) is a rare tumor. The gene mutation of ovarian SCC remains unclear. We herein report a recurrent case of ovarian squamous cell carcinoma with MET gene copy number variation.

Case presentation

A 60-year-old woman presented with recurrence of ovarian SCC 8 months after primary surgery. Adhesiolysis, right abdominal wall mass excision, prosthetics, enterectomy, enterostomy and partial cystectomy were performed by laparoscope. Pathologic examination demonstrated metastatic squamous cell carcinoma in ileocecus, rectum and abdominal wall muscle. MET gene copy number was elevated with copy number of six in this case. Postoperatively, the patient was treated with four cycles of combination chemotherapy with docetaxel and carboplatin. The patient was free of disease at 20 months’ follow-up.

Conclusions

Optimal cytoreductive surgery combined with platinum-based chemotherapy is recommended currently for not only primary tumor but also recurrence. For patients with malignant transformation in OMCT, prompt diagnosis and individualized treatment are crucial for better prognosis. Increased copy number of MET may be correlated with her poor PFS and can be a potential therapeutic target for this case.

TR1801-ADC: a highly potent cMet antibody-drug conjugate with high activity in patient-derived xenograft models of solid tumors

cMet is a well‐characterized oncogene that is the target of many drugs including small molecule and biologic pathway inhibitors, and, more recently, antibody–drug conjugates (ADCs). However, the clinical benefit from cMet‐targeted therapy has been limited. We developed a novel cMet‐targeted ‘third‐generation’ ADC, TR1801‐ADC, that was optimized at different levels including specificity, stability, toxin–linker, conjugation site, and in vivo efficacy. Our nonagonistic cMet antibody was site‐specifically conjugated to the pyrrolobenzodiazepine (PBD) toxin–linker tesirine and has picomolar activity in cancer cell lines derived from different solid tumors including lung, colorectal, and gastric cancers. The potency of our cMet ADC is independent of MET gene copy number, and its antitumor activity was high not only in high cMet‐expressing cell lines but also in medium‐to‐low cMet cell lines (40 000–90 000 cMet/cell) in which a cMet ADC with tubulin inhibitor payload was considerably less potent. In vivo xenografts with low–medium cMet expression were also very responsive to TR1801‐ADC at a single dose, while a cMet ADC using a tubulin inhibitor showed a substantially reduced efficacy. Furthermore, TR1801‐ADC had excellent efficacy with significant antitumor activity in 90% of tested patient‐derived xenograft models of gastric, colorectal, and head and neck cancers: 7 of 10 gastric models, 4 of 10 colorectal cancer models, and 3 of 10 head and neck cancer models showed complete tumor regression after a single‐dose administration. Altogether, TR1801‐ADC is a new generation cMet ADC with best‐in‐class preclinical efficacy and good tolerability in rats.

C7 peptide inhibits hepatocellular carcinoma metastasis by targeting the HGF/c-Met signaling pathway

Hepatocellular carcinoma (HCC), characterized by a high rate of metastasis and recurrence after surgery, is caused by malignant proliferation of hepatocytes with epigenetic and/or genetic mutations. In particular, abnormal activation of the hepatocyte growth factor (HGF)-/c-mesenchymal-epithelial transition receptor (c-Met) axis is closely associated with HCC metastasis. Unfortunately, effective treatments or drugs that target the HGF/c-Met signaling pathway are still in the research pipeline. Here, a c-Met inhibitor named the C7 peptide, which can inhibit both HGF and c-Met, can significantly inhibit HGF-induced (but not EGF-induced) cell migration and suppress the phosphorylation of c-Met, Akt and Erk1/2. Moreover, the C7 peptide can also significantly suppress tumor metastasis in nude mice and the phosphorylation of c-Met. Together, our current findings, demonstrated that the C7 peptide can inhibit HGF-induced cancer cell migration and invasion through the inhibition of Akt and Erk1/2. Identification of a peptide that can block HGF/c-Met signaling provides new insight into the mechanism of HCC and future clinical treatments.

MET Genomic Alterations in Head and Neck Squamous Cell Carcinoma (HNSCC): Rapid Response to Crizotinib in a Patient with HNSCC with a Novel MET R1004G Mutation

Identification of effective targeted therapies for recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) remains an unmet medical need. A patient with platinum-refractory recurrent oral cavity HNSCC underwent comprehensive genomic profiling (CGP) that identified an activating MET mutation (R1004). The patient was treated with the oral MET tyrosine kinase inhibitor crizotinib with rapid response to treatment.Based on this index case, we determined the frequency of MET alterations in 1,637 HNSCC samples, which had been analyzed with hybrid capture-based CGP performed in the routine course of clinical care. The specimens were sequenced to a median depth of >500× for all coding exons from 182 (version 1, n = 24), 236 (version 2, n = 326), or 315 (version 3, n = 1,287) cancer-related genes, plus select introns from 14 (version 1), 19 (version 2), or 28 (version 3) genes frequently rearranged in cancer. We identified 13 HNSCC cases (0.79%) with MET alterations (4 point mutation events and 9 focal amplification events). MET-mutant or amplified tumors represent a small but potentially actionable molecular subset of HNSCC. KEY POINTS: This case report is believed to be the first reported pan-cancer case of a patient harboring a MET mutation at R1004 demonstrating a clinical response to crizotinib, in addition to the first documented case of head and neck squamous cell carcinoma (HNSCC) with any MET alteration responding to crizotinib.The positive response to MET inhibition in this patient highlights the significance of comprehensive genomic profiling in advanced metastatic HNSCC to identify actionable targetable molecular alterations as current treatment options are limited.

Challenges facing antiangiogenesis therapy: The significant role of hypoxia-inducible factor and MET in development of resistance to anti-vascular endothelial growth factor-targeted therapies

It is now fully recognized that along with multiple physiological functions, angiogenesis is also involved in the fundamental process and pathobiology of several disorders including cancer. Recent studies have fully established the role of angiogenesis in cancer progression as well as invasion and metastasis. Consequently, many therapeutic agents such as monoclonal antibodies targeting angiogenesis pathway have been introduced in clinic with the hope for improving the outcomes of cancer therapy. Bevacizumab (Avastin®) was the first anti-vascular endothelial growth factor (VEGF) targeting monoclonal antibody developed with this purpose and soon received its accelerated US Food and Drug Administration (FDA) approval for treatment of patients with metastatic breast cancer in 2008. However, the failure to meet expecting results in different follow-up studies, forced FDA to remove bevacizumab approval for metastatic breast cancer. Investigations have now revealed that while suppressing VEGF pathway initially decreases tumor progression rate and vasculature density, activation of several interrelated pathways and signaling molecules following VEGF blockade compensate the insufficiency of VEGF and initially blocked angiogenesis, explaining in part the failure observed with bevacizumab single therapy. In present review, we introduce some of the main pathways and signaling molecules involved in angiogenesis and then propose how their interconnection may result in development of resistance to bevacizumab.

MTOR inhibition reversed drug resistance after combination radiation with erlotinib in lung adenocarcinoma

Objective

To investigate the effects of mTOR inhibition on drug resistance in lung adenocarcinoma after combined radiation and erlotinib therapy.

Results

Combined radiation and erlotinib therapy produced clear radiosensitization effects both in vitro and in vivo; however, tumor cells remained drug resistant. Additionally, combined radiation and erlotinib therapy significantly increased p-AKT and p-P70 levels. After mTOR inhibition, the number of surviving cells significantly decreased compared with that before inhibition, and the in vivo growth curve was significantly reduced.

Methods

The effects of combined radiation and erlotinib therapy on tumor inhibition and drug resistance were evaluated by in vitro survival curves in PC9 lung adenocarcinoma cell line and in vivo growth curves in nude mouse xenograft tumor model respectively. The association between tumor drug resistance and the phosphatidylinositol 3-kinase/protein kinase B/mechanistic target of rapamycin (PI3K-AKT-mTOR) pathway was measured by western blot, assessing the changes in protein kinase B (AKT), phosphor-AKT (p-AKT), P70, and p-P70 protein levels. MTOR was inhibited using everolimus, and changes in AKT, p-AKT, P70, and p-P70 levels were observed. Furthermore, changes in in vitro survival curves, and in vivo growth curves before and after mTOR inhibition were evaluated to confirm its effects on drug resistance in lung adenocarcinoma after combined radiation and TKI therapy.

Conclusion

mTOR was associated with drug resistance in lung adenocarcinoma after radiation combined with TKI, and MTOR inhibition reversed drug resistance in lung adenocarcinoma after combined radiation and TKI therapy.

PKG II reverses HGF-triggered cellular activities by phosphorylating serine 985 of c-Met in gastric cancer cells

Previous studies showed that type II cGMP-dependent protein kinase G (PKG II) could inhibit the activation of epidermal growth factor receptor (EGFR). Both c-Met and EGFR belong to family of receptor tyrosine kinases (RTKs) and have high molecular analogy. However, the effect of PKG II on c-Met activation is unclear. This study was designed to investigate the inhibitory effect of PKG II on the activation of c-Met and consequent biological activities. The results from CCK8 assay, Transwell assay and TUNEL assay showed that HGF enhanced cell proliferation and migration, and decreased cell apoptosis. Activated PKG II reversed the above changes caused by HGF. Immunoprecipitation and Western blotting results showed that PKG II could bind with c-Met and phosphorylate its Ser985, and thereby inhibited HGF-induced activation of c-Met and MAPK/ERK and PI3K/Akt/mTOR mediated signal transduction. When Ser985 of c-Met was mutated to Alanine for preventing phosphorylation of this site, the blocking effect of PKG II on c-Met activation was annulled. When Ser985 of c-Met was mutated to Aspartic acid for mimicking phosphorylation of this site, HGF-induced activation of c-Met was prevented. In conclusion, the results indicated that PKG II could block c-Met activation via phosphorylating Ser985 of this RTK.

Hepatocyte growth factor is a prognostic marker in patients with colorectal cancer: a meta-analysis

Hepatocyte growth factor (HGF) is a crucial factor associated with development, progression and metastasis of colorectal cancer (CRC). However, its prognostic value remains unclear. Thus studies referring to the correlation between HGF and CRC patients’ prognosis were included to explore the role of HGF in CRC. At last nine articles were included. The results showed that the over-expression of HGF was associated with a poor prognosis, presented through overall survival (OS, Hazard ratio (HR) = 2.50, 95% confidence interval (CI): 2.12–2.96) and disease-free survival (DFS, HR = 1.99, 95% CI: 1.59–2.50). Subgroup analysis indicated that no significant difference was found between the Asian countries (OS: HR = 2.37; DFS: HR = 2.02) and the non-Asian countries (OS: HR = 3.15; DFS: HR = 1.87), between the studies that used univariate analyses (OS: HR = 2.51; DFS: HR = 2.07) and those that used multivariate analyses (OS: HR = 2.65; DFS: HR = 1.78), and between metastatic CRC (OS: HR = 2.26; DFS: HR = 2.06) and stage I-IV CRC (OS: HR = 3.08; DFS: HR = 0.70). Our meta-analysis has shown that the over-expression of HGF is valuable in CRC prognosis evaluation. This conclusion should be further confirmed by large-sample cohort studies.

Identifying ultrasensitive HGF dose-response functions in a 3D mammalian system for synthetic morphogenesis

Nonlinear responses to signals are widespread natural phenomena that affect various cellular processes. Nonlinearity can be a desirable characteristic for engineering living organisms because it can lead to more switch-like responses, similar to those underlying the wiring in electronics. Steeper functions are described as ultrasensitive, and can be applied in synthetic biology by using various techniques including receptor decoys, multiple co-operative binding sites, and sequential positive feedbacks. Here, we explore the inherent non-linearity of a biological signaling system to identify functions that can potentially be exploited using cell genome engineering. For this, we performed genome-wide transcription profiling to identify genes with ultrasensitive response functions to Hepatocyte Growth Factor (HGF). We identified 3,527 genes that react to increasing concentrations of HGF, in Madin-Darby canine kidney (MDCK) cells, grown as cysts in 3D collagen cell culture. By fitting a generic Hill function to the dose-responses of these genes we obtained a measure of the ultrasensitivity of HGF-responsive genes, identifying a subset with higher apparent Hill coefficients (e.g. MMP1, TIMP1, SNORD75, SNORD86 and ERRFI1). The regulatory regions of these genes are potential candidates for future engineering of synthetic mammalian gene circuits requiring nonlinear responses to HGF signalling.

Biomarker development in MET-targeted therapy

Activation of the MET receptor tyrosine kinase by its ligand, hepatocyte growth factor (HGF), has been implicated in a variety of cellular processes, including cell proliferation, survival, migration, motility and invasion, all of which may be enhanced in human cancers. Aberrantly activated MET/HGF signaling correlates with tumorigenesis and metastasis, and is regarded as a robust target for the development of novel anti-cancer treatments. Various clinical trials were conducted to evaluate the safety and efficacy of selective HGF/MET inhibitors in cancer patients. There is currently no optimal or standardized method for accurate and reliable assessment of MET levels, or other biomarkers that are predictive of the patient response to MET-targeted therapeutics. In this review, we discuss the importance of accurate HGF/MET signal detection as a predictive biomarker to guide patient selection for clinical trials of MET-targeted therapies in human cancers.

Sorafenib and DE605, a novel c-Met inhibitor, synergistically suppress hepatocellular carcinoma

Sorafenib, an oral multikinase inhibitor of Raf, VEGF and PDGF receptor signaling is approved for advanced hepatocellular carcinoma (HCC). One strategy to improve HCC therapy is to combine agents that target key signaling pathways. Aberrant mesenchymal-epithelial transition factor (c-Met) activation is associated with a variety of human malignancies and therefore represents a target for therapy. In this study, we investigated a novel c-Met inhibitor, DE605, together with sorafenib in hepatocellular carcinoma cells in vitro and in vivo. DE605 and sorafenib synergistically induced apoptosis in hepatocellular carcinoma cells. Mechanistically, DE605 activated the FGFR3/Erk pathway, which in turn was inhibited by sorafenib, resulting in synergism. Finally, DE605 and sorafenib significantly inhibited growth of PLC/PRF/5 hepatocellular carcinoma tumor xenografts in athymic nude mice. Importantly, no obvious weight loss (toxicity) was detected. Thus in combination, DE605 and sorafenib target complementary anti-apoptotic pathways and synergistically suppress HCC, providing the rationale for clinical studies with this novel combination.

Met tyrosine kinase inhibitor, PF-2341066, suppresses growth and invasion of nasopharyngeal carcinoma

Purpose

We explored the effect of hepatocyte growth factor (HGF)/Met signaling pathway on nasopharyngeal carcinoma (NPC) cells in vitro and in vivo, and investigated the ability of Met tyrosine kinase inhibitor (TKI) to block HGF-induced biological signaling.

Experimental design

Met TKI inhibitor PF-2341066 alone, or in combination with cisplatin, was investigated for its ability to block HGF-induced signaling and biological effects in vitro and in vivo. HGF/Met expression and activation of signaling in NPC cells were detected by using Western blot and immunohistochemistry. Biological evaluation, including wound healing, cell proliferation, and invasion of NPC cells, was also examined, and the correlation between HGF/Met expression of primary and metastatic tumor in NPC patients and clinical prognosis were also analyzed.

Results

Met TKI inhibitor, PF-2341066, inhibited growth of NPC cells in vivo with half maximal inhibitory concentration of 0.79±0.21 μmol/L, and suppressed invasion and migration of NPC cells; also, the inhibition of PF-2341066 was synergized with cisplatin treatment. Compared with the control group, Met TKI inhibited metastasis of transplanted NPC in nude mice (the number of live metastases [mean ± SD]: 5.8±2.2 versus 11.8±2.2, P=0.03; the number of lung metastases: 2.3±1.5 versus 5.3±0.9, P=0.06). HGF was widely expressed in both primary and metastatic lesions while Met expression of metastatic lesions was higher than that of primary lesions (primary lesions: 24.7%; liver metastases: 40%; lung metastases: 29%; lymph node metastases: 29%, P<0.05), and overall survival of NPC patients with higher expression of Met was shorter (P=0.13).

Conclusion

Our results demonstrated that HGF/Met signaling promoted NPC growth, further resulting in metastasis and poor prognosis. Met TKI, PF-2341066, showed potent antitumor activity in vivo and in vitro which was enhanced by combination with cisplatin. Our study implied that HGF/Met signaling was the potential therapeutic target in NPC, and blockage of the signaling could prevent growth and metastasis of NPC and derive clinical benefit.

MiR-449c inhibits gastric carcinoma growth

AIMS

Gastric carcinoma (GC) is among the leading causes of cancer-related deaths in China. Growing evidence indicates that dysregulation of miRNAs contributes to GC development. Although it has been shown that miR-449c acts as a tumor suppressor in lung cancer, the role of miR-449c in GC remains unclear.

MAIN METHODS

Here, we analyzed miR-449c levels in GC tissues and cell lines by RT-qPCR. We also overexpressed and inhibited miR-449c by transfecting miRNA mimics and antisense oligonucleotides (ASO), respectively. Cell growth was analyzed by MTT assay, and cell apoptosis was evaluated by FACS analysis. MiR-449c target genes were predicted using bioinformatics algorithms and confirmed by a dual luciferase reporter assay.

KEY FINDINGS

We detected lower miR-449c levels in GC tissues; the low miR-449c levels correlated with low survival rate. Overexpression of miR-449c inhibited cell growth and promoted apoptosis, while depletion of miR-449c increased cell growth and suppressed apoptosis. Moreover, the 3' UTR of MET, an oncogene that activates tumor cell growth, appeared to be targeted by miR-449c.

SIGNIFICANCE

Together, we showed that the reduced miR-449c levels in GC tissues promote GC growth, which possibly contributes to the low survival rate of GC patients. Mechanistically, miR-449c may target MET to suppress GC cell growth.

Gastric cancer and gene copy number variation: emerging cancer drivers for targeted therapy

Gastric cancer (GC) is among the most common malignancy in the world with poor prognosis and limited treatment options. It has been established that gastric carcinogenesis is caused by a complex interaction between host and environmental factors. Copy number variation (CNV) refers to a form of genomic structural variation that results in abnormal gene copy numbers, including gene amplification, gain, loss and deletion. DNA CNV is an important influential factor for the expression of both protein-coding and non-coding genes, affecting the activity of various signaling pathways. CNV arises as a result of preferential selection that favors cancer development, and thus, targeting the amplified 'driver genes' in GC may provide novel opportunities for personalized therapy. The detection of CNVs in chromosomal or mitochondrial DNA from tissue or blood samples may assist the diagnosis, prognosis and targeted therapy of GC. In this review, we discuss the recent CNV discoveries that shed light on the molecular pathogenesis of GC, with a specific emphasis on CNVs that display diagnostic, prognostic or therapeutic significances in GC.

Synthesis and anticancer activity of 4-aza-daurinol derivatives

Daurinol, a natural aryl naphthalene lactone, has been reported to have antiproliferative activity against various cell lines, and has also been shown to be efficacious in an in vivo xenograft mouse model. In this study, we tried to discover a new scaffold that enables both rapid structure-activity relationship study of daurinol and scalable synthesis of active compounds. 4-Aza-daurinol, a bioisosterism-based scaffold of daurinol, was designed and 17 analogues were synthesized and evaluated against five representative cancer cell lines. Among them, the 2,3-dihydrobenzo[b][1,4]dioxinyl derivative was found to be the most potent and showed similar activity and tendency as daurinol.

Pharmacokinetics and pharmacodynamics of rilotumumab: a decade of experience in preclinical and clinical cancer research

Rilotumumab is a fully human monoclonal antibody against hepatocyte growth factor, the only known ligand of the MET receptor. Over the last decade, rilotumumab has been extensively tested in preclinical studies and in clinical studies in a variety of cancer types. In this review, we examine the pharmacokinetic and pharmacodynamic data that have been collected in the rilotumumab programme to date, and discuss retrospectively how the knowledge acquired in this programme can be applied to a number of key issues in oncology drug development, including: (i) using preclinical data to inform first-in-human study design; (ii) the role of biomarkers in the identification of a target patient population; (iii) the potential for drug interactions between therapeutic proteins and other anticancer agents; and (iv) pharmacokinetic and pharmacodynamic considerations in phase 3 study design.

Recent Progress and Advances in HGF/MET-Targeted Therapeutic Agents for Cancer Treatment

The hepatocyte growth factor (HGF): MET axis is a ligand-mediated receptor tyrosine kinase pathway that is involved in multiple cellular functions, including proliferation, survival, motility, and morphogenesis. Aberrancy in the HGF/MET pathway has been reported in multiple tumor types and is associated with tumor stage and prognosis. Thus, targeting the HGF/MET pathway has become a potential therapeutic strategy in oncology development in the last two decades. A number of novel therapeutic agents-either as therapeutic proteins or small molecules that target the HGF/MET pathway-have been tested in patients with different tumor types in clinical studies. In this review, recent progress in HGF/MET pathway-targeted therapy for cancer treatment, the therapeutic potential of HGF/MET-targeted agents, and challenges in the development of such agents will be discussed.

HGF/c-MET Axis in Tumor Microenvironment and Metastasis Formation

Tumor metastases are responsible for approximately 90% of all cancer-related deaths. Metastasis formation is a multistep process that requires acquisition by tumor cells of a malignant phenotype that allows them to escape from the primary tumor site and invade other organs. Each step of this mechanism involves a deep crosstalk between tumor cells and their microenvironment where the host cells play a key role in influencing metastatic behavior through the release of many secreted factors. Among these signaling molecules, Hepatocyte Growth Factor (HGF) is released by many cell types of the tumor microenvironment to target its receptor c-MET within the cells of the primary tumor. Many studies reveal that HGF/c-MET axis is implicated in various human cancers, and genetic and epigenetic gain of functions of this signaling contributes to cancer development through a variety of mechanisms. In this review, we describe the specific types of cells in the tumor microenvironment that release HGF in order to promote the metastatic outgrowth through the activation of extracellular matrix remodeling, inflammation, migration, angiogenesis, and invasion. We dissect the potential use of new molecules that interfere with the HGF/c-MET axis as therapeutic targets for future clinical trials in cancer disease.

Association Analysis of MET Gene Polymorphism with Papillary Thyroid Carcinoma in a Chinese Population

To investigate the association of MET SNPs with gender disparity in thyroid tumors, as well as the metastasis and prognosis of patients, 858 patients with papillary thyroid carcinoma (PTC), 556 patients with nodular goiter, and 896 population-based normal controls were recruited. The genotyping of MET SNPs was carried out using the Sequenom MassARRAY system. The distribution of MET SNPs (rs1621 and rs6566) was different among groups. Gender stratification analysis revealed a significant association between the rs1621 genotype and PTC in female patients (P = 0.037), but not in male patients (P > 0.05). For female patients, the rs1621 AG genotype was significantly higher in patients with PTC than in normal controls (P = 0.01) and revealed an increasing risk of PTC (OR: 1.465, 95% CI: 1.118-1.92). However, association analysis of the rs1621 genotype with metastasis and prognosis revealed no significant correlation in both male and female patients. The findings of our study showed that polymorphism of SNP locus rs1621 in MET gene may be associated with gender disparity in PTC. Higher AG genotypes in rs1621 were correlated with PTC in female patients, but not in male patients.

Discovery and SAR study of c-Met kinase inhibitors bearing an 3-amino-benzo[d]isoxazole or 3-aminoindazole scaffold

A series of 3-amino-benzo[d]isoxazole-/3-aminoindazole-based compounds were designed, synthesized and pharmacologically evaluated as tyrosine kinase c-Met inhibitors. The SAR study was conducted leading to identification of nine compounds (8d, 8e, 12, 28a-d, 28h and 28i) with IC50s less than 10nM against c-Met. Compound 28a stood out as the most potent c-Met inhibitor displaying potent inhibitory effects both at enzymatic (IC50=1.8 nM) and cellular (IC50=0.18 μM on EBC-1 cells) levels. In addition, 28a had a relatively good selectivity compared to a panel of our in-house 14 RTKs.

Experimental study on the regulation of erlotinib-induced radiosensitization with an anti-c-MET monoclonal antibody

PURPOSE

Erlotinib is a novel therapeutic agent for cancer treatment. This study was performed to investigate the role of c-MET-PI3K-AKT pathway in the regulation of erlotinib-induced radiosensitization.

METHODS

A973 lung adenocarcinoma cells treated with 6 Gy of radiation were incubated in the presence of erlotinib. The apoptotic rate after 24 hours, the colony-formating rate after 14 days, and changes in the c-MET expression levels after 14 days of irradiation were examined. Surviving fractions in different treatment groups (blank control, radiation alone, erlotinib alone, anti-c-MET monoclonal antibody alone, combined erlotinib and radiation, and combined erlotinib and radiation with anti-c-MET monoclonal antibody groups) were determined, the survival curves were plotted, and the sensitizer enhancement ratio was calculated using colony formation assays. Expressions of c-MET, p-c-MET, PI3K, AKT, and p-AKT in cells in different treatment groups were examined by Western blot analysis.

RESULTS

The apoptotic rate in the combined erlotinib and radiation group was higher than those in single treatment groups; however, the colony-forming rate remained approximately 2.04 ± 1.02%. The expression of c-MET in colony-forming cells in the combined group significantly increased, and the blockade of c-MET activity significantly enhanced the radiosensitizing effect of erlotinib. The expression of c-Met, p-c-MET, PI3K, AKT, and p-AKT among colony-forming cells significantly decreased upon the inhibition of c-MET.

CONCLUSIONS

Upregulated activity of the c-MET-PI3K-AKT pathway was found to be important for cell survival under combined the treatment with erlotinib and radiation. The blockade of the c-MET-PI3K-AKT signaling pathway enhanced the radiosensitizing effect of erlotinib.

Novel Suppressive Effects of Ketotifen on Migration and Invasion of MDA-MB-231 and HT-1080 Cancer Cells

The high mortality rates associated with cancer reflect the metastatic spread of tumor cells from the site of their origin. Metastasis, in fact, is the cause of 90% of cancer deaths. Therefore, considerable effort is being made to inhibit metastasis. In the present study, we screened ketotifen for anti-migratory and anti-invasive activities against MDA-MB-231 breast cancer and HT-1080 fibrosarcoma cancer cells. Cancer cell migration and invasion were measured using multi-well chambers. Additionally, western blots were used to examine the effects of ketotifen on the expressions of CDC42, Rho, Rac, and matrix metalloproteinase 9 (MMP-9). The results showed that ketotifen dose-dependently suppressed the migration and invasion of MDA-MB-231 and HT-1080 cells. Ketotifen also suppressed the expressions of CDC42, Rac, and Rho, which, significantly, are involved in MDA-MB-231 and HT-1080 cancer cell migration. Moreover, ketotifen suppressed the expression and activity of MMP-9, which is involved in degradation of the extracellular matrix leading to invasion. The overall data suggested that ketotifen suppresses the migration and invasion of MDA-MB-231 and HT-1080 cancer cells via inhibition of CDC42, Rac, Rho, and MMP-9 expression.

[Research progress of HGF/MET signaling pathway in EGFR-TKI resistance in non-small cell lung cancer]

肺癌是世界上最常见的恶性肿瘤之一，其中非小细胞肺癌约占80%。肝细胞生长因子（hepatocyte growth factor, HGF）/上皮间质转化因子（mesenchymal-epithelial transition factor, MET）信号通路在许多生物学进程中都发挥着多效性影响，然而，在多种类型的肿瘤中都观察到HGF/MET信号通路的异常激活，并且通过生长因子受体和其他致癌性基因受体通路促进细胞增殖和转移。近年来，HGF/MET信号通路的异常激活被认为是对表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factor receptor tyrosine kinase inhibitor, EGFR-TKI）产生耐药的一个重要原因。本文将重点阐述该通路异常激活与非小细胞肺癌患者EGFR-TKI耐药的联系。

New radiotracers for imaging of vascular targets in angiogenesis-related diseases

Tremendous advances over the last several decades in positron emission tomography (PET) and single photon emission computed tomography (SPECT) allow for targeted imaging of molecular and cellular events in the living systems. Angiogenesis, a multistep process regulated by the network of different angiogenic factors, has attracted world-wide interests, due to its pivotal role in the formation and progression of different diseases including cancer, cardiovascular diseases (CVD), and inflammation. In this review article, we will summarize the recent progress in PET or SPECT imaging of a wide variety of vascular targets in three major angiogenesis-related diseases: cancer, cardiovascular diseases, and inflammation. Faster drug development and patient stratification for a specific therapy will become possible with the facilitation of PET or SPECT imaging and it will be critical for the maximum benefit of patients.

The c-Met Inhibitor MSC2156119J Effectively Inhibits Tumor Growth in Liver Cancer Models

The mesenchymal-epithelial transition factor (c-Met) is a receptor tyrosine kinase with hepatocyte growth factor (HGF) as its only high-affinity ligand. Aberrant activation of c-Met is associated with many human malignancies, including hepatocellular carcinoma (HCC). We investigated the in vivo antitumor and antimetastatic efficacy of the c-Met inhibitor MSC2156119J (EMD 1214063) in patient-derived tumor explants. BALB/c nude mice were inoculated with MHCC97H cells or with tumor fragments of 10 patient-derived primary liver cancer explants selected according to c-Met/HGF expression levels. MSC2156119J (10, 30, and 100 mg/kg) and sorafenib (50 mg/kg) were administered orally as single-agent treatment or in combination, with vehicle as control. Tumor response, metastases formation, and alpha fetoprotein (AFP) levels were measured. MSC2156119J inhibited tumor growth and induced complete regression in mice bearing subcutaneous and orthotopic MHCC97H tumors. AFP levels were undetectable after 5 weeks of MSC2156119J treatment, and the number of metastatic lung foci was reduced. Primary liver explant models with strong c-Met/HGF activation showed increased responsiveness to MSC2156119J, with MSC2156119J showing similar or superior activity to sorafenib. Tumors characterized by low c-Met expression were less sensitive to MSC2156119J. MSC2156119J was better tolerated than sorafenib, and combination therapy did not improve efficacy. These findings indicate that selective c-Met/HGF inhibition with MSC2156119J is associated with marked regression of c-Met high-expressing tumors, supporting its clinical development as an antitumor treatment for HCC patients with active c-Met signaling.

Quantum dot-based nanoprobes for in vivo targeted imaging

Fluorescent semiconductor quantum dots (QDs) have attracted tremendous attention over the last decade. The superior optical properties of QDs over conventional organic dyes make them attractive labels for a wide variety of biomedical applications, whereas their potential toxicity and instability in biological environment have puzzled scientific researchers. Much research effort has been devoted to surface modification and functionalization of QDs to make them versatile probes for biomedical applications, and significant progress has been made over the last several years. This review article aims to describe the current state-of-the-art of the synthesis, modification, bioconjugation, and applications of QDs for in vivo targeted imaging. In addition, QD-based multifunctional nanoprobes are also summarized.