MET amplification as a potential therapeutic target in gastric cancer

Our aim was to investigate both the prevalence of MET amplification in gastric cancer as well as the potential of this genetic alteration to serve as a therapeutic target in gastric cancer. MET amplification was assessed by initial screening with a PCR-based copy number assay followed by confirmatory FISH analysis in formalin-fixed, paraffin-embedded specimens of gastric cancer obtained at surgery. The effects of MET tyrosine kinase inhibitors (MET-TKIs) in gastric cancer cells with or without MET amplification were also examined. The median MET copy number in 266 cases of gastric cancer was 1.7, with a range of 0.41 to 21.3. We performed FISH analysis for the 15 cases with the highest MET copy numbers. MET amplification was confirmed in the four assessable cases with a MET copy number of at least 4, whereas MET amplification was not detected in those with a gene copy number of <4. The prevalence of MET amplification was thus 1.5% (4 out of 266 cases). Inhibition of MET by MET-TKIs resulted in the induction of apoptosis accompanied by attenuation of downstream MET signaling in gastric cancer cell lines with MET amplification but not in those without this genetic change. MET amplification identifies a small but clinically important subgroup of gastric cancer patients who are likely to respond to MET-TKIs. Furthermore, screening with a PCR-based copy number assay is an efficient way to reduce the number of patients requiring confirmation of MET amplification by FISH analysis.     

CXCR7 expression is associated with disease-free and disease-specific survival in cervical cancer patients

Background:

The CXC chemokine receptor (CXCR)7 is involved in tumour development and metastases formation. The aim of the present study was to determine protein expression of CXCR7, its putative co-receptors epidermal growth factor receptor (EGFR) and CXCR4, its predominant ligand CXCL12, their co-dependency and their association with survival in cervical cancer patients.

Methods:

CXC chemokine receptor 7, EGFR, CXCR4 and CXCL12 expression were determined immunohistochemically in 103 paraffin-embedded, cervical cancers. Subsequently, associations with patient characteristics were assessed and survival analyses were performed.

Results:

CXC chemokine receptor 7 was expressed by 43% of tumour specimens, in a large majority of cases together with either EGFR or CXCR4 (double positive), or both (triple positive). The CXCR7 expression was associated with tumour size (P=0.013), lymph node metastasis (P=0.001) and EGFR expression (P=0.009). CXC chemokine receptor 7 was independently associated with disease-free survival (hazard ratio (HR)=4.3, 95% confidence intervals (CI) 1.7–11.0, P=0.002), and strongly associated with disease-specific survival (HR=3.9, 95% CI 1.5–10.2, P=0.005).

Conclusion:

CXC chemokine receptor 7 expression predicts poor disease-free and disease-specific survival in cervical cancer patients, and might be a promising new therapeutic marker. In a large majority of cases, CXCR7 is co-expressed with CXCR4 and/or EGFR, supporting the hypothesis that these receptors assist in CXCR7 signal transduction.     

The MET axis as a therapeutic target

The MET receptor tyrosine kinase and its ligand hepatocyte growth factor (HGF) have been implicated in transformation of a variety of malignancies. Chronic or dysregulated activation of the MET/HGF pathway may lead to increased cell growth, invasion, angiogenesis, and metastasis, reduced apoptosis, altered cytoskeletal functions and other biological changes. It has been suggested that ligand activated MET stimulation can be sufficient for a transforming phenotype. In addition, amplification and activation mutations (germline and/or somatic) within the tyrosine kinase domain, juxtamembrane domain, or semaphorin domain have been identified for MET. MET gain-of-function mutations lead to either deregulated or prolonged tyrosine kinase activity, which are instrumental to its transforming activity. A number of therapeutic strategies targeting ligand-dependent activation or the kinase domain have been employed to inhibit MET. The different structural requirements for activation of signaling events and biological functions regulated by MET will be summarized. Therapeutic targets and current pre-clinical and clinical approaches will be described. Targeting the HGF/MET pathway, alone or in combination with standard therapies, is likely to improve present therapies in MET-dependent malignancies.     

HER2 as a novel therapeutic target for cervical cancer

Surgery and radiation are the current standard treatments for cervical cancer. However, there is no effective therapy for metastatic or recurrent cases, necessitating the identification of therapeutic targets. In order to create preclinical models for screening potential therapeutic targets, we established 14 patient-derived xenograft (PDX) models of cervical cancers using subrenal implantation methods. Serially passaged PDX tumors retained the histopathologic and genomic features of the original tumors. Among the 9 molecularly profiled cervical cancer patient samples, a HER2-amplified tumor was detected by array comparative genomic hybridization and targeted next-generation sequencing. We confirmed HER2 overexpression in the tumor and serially passaged PDX. Co-administration of trastuzumab and lapatinib in the HER2-overexpressed PDX significantly inhibited tumor growth compared to the control. Thus, we established histopathologically and genomically homologous PDX models of cervical cancer using subrenal implantation. Furthermore, we propose HER2 inhibitor-based therapy for HER2-amplified cervical cancer refractory to conventional therapy.     

Orthogonal MET analysis in a population‐representative stage II–III colon cancer cohort: prognostic and potential therapeutic implications

Clinical trials for MET inhibitors have demonstrated limited success for their use in colon cancer (CC). However, clinical efficacy may be obscured by a lack of standardisation in MET assessment for patient stratification. In this study, we aimed to determine the molecular context in which MET is deregulated in CC using a series of genomic and proteomic tests to define MET expression and identify patient subgroups that should be considered in future studies with MET‐targeted agents. To this aim, orthogonal expression analysis of MET was conducted in a population‐representative cohort of stage II/III CC patients (n = 240) diagnosed in Northern Ireland from 2004 to 2008. Targeted sequencing was used to determine the relative incidence of MET R970C and MET T992I mutations within the cohort. MET amplification was assessed using dual‐colour dual‐hapten brightfield in situ hybridisation (DDISH). Expression of transcribed MET and c‐MET protein within the cohort was assessed using digital image analysis on MET RNA in situ hybridisation (ISH) and c‐MET immunohistochemistry (IHC) stained slides. We found that less than 2% of the stage II/III CC patient population assessed demonstrated a genetic MET aberration. Determination of a high MET RNA‐ISH/low c‐MET IHC protein subgroup was found to be associated with poor 5‐year cancer‐specific outcomes compared to patients with concordant MET RNA‐ISH and c‐MET IHC protein expression (HR 2.12 [95%CI: 1.27–3.68]). The MET RNA‐ISH/c‐MET IHC protein biomarker paradigm identified in this study demonstrates that subtyping of MET expression may be required to identify MET‐addicted malignancies in CC patients who will truly benefit from MET inhibition.     

Association of CXCR4 and CCR7 chemokine receptor expression and lymph node metastasis in human cervical cancer.

BACKGROUND: The chemokine receptors CXCR4 and CCR7 have been suggested to play an important role in cancer invasion and metastasis. The expression of these receptors in human cervical cancer, however, has seldom been characterized. PATIENTS AND METHODS: We investigated the expression of CXCR4 and CCR7 in cervical cancer specimens and determined the association between their expression and the clinicopathological features observed, including patient outcome. RESULTS: CXCR4 expression was significantly higher in elderly patients (P=0.025); it was also significantly increased in patients with cancers displaying large tumor size (P=0.010), deep stromal invasion (P=0.0004), lymph-vascular space involvement (P=0.0002), or lymph node metastasis (P<0.0001). CCR7 expression was significantly higher in cases of squamous cell carcinomas (P=0.010) and in patients with cancers showing large tumor size (P<0.0001), deep stromal invasion (P<0.0001), vaginal invasion (P=0.047), lymph-vascular space involvement (P=0.012), or lymph node metastasis (P<0.0001). Logistic regression analysis revealed that deep stromal invasion (P=0.017) and CXCR4 (P=0.016) and CCR7 (P=0.022) expression were independent factors that influenced pelvic lymph node metastasis. The disease-free survival and overall survival (OS) rates of patients exhibiting both CXCR4 and CCR7 expression were significantly reduced (P<0.0001). In addition, the expression of both CXCR4 and CCR7 was an independent prognostic factor for OS (95% confidence interval=1.03-17.86; P=0.046). CONCLUSIONS: CXCR4 and CCR7 expression may be associated with lymph node metastasis; moreover, the expression of these receptors can serve as an indicator of poor prognosis in patients with cervical cancer.     

Sphingosine kinase 1 is a reliable prognostic factor and a novel therapeutic target for uterine cervical cancer

Sphingosine kinase 1 (SPHK1), an oncogenic kinase, has previously been found to be upregulated in various types of human malignancy and to play a crucial role in tumor development and progression. Although SPHK1 has gained increasing prominence as an important enzyme in cancer biology, its potential as a predictive biomarker and a therapeutic target in cervical cancer remains unknown. SPHK1 expression was examined in 287 formalin-fixed, paraffin-embedded cervical cancer tissues using immunohistochemistry, and its clinical implications and prognostic significance were analyzed. Cervical cancer cell lines including HeLa and SiHa were treated with the SPHK inhibitors SKI-II or FTY720, and effects on cell survival, apoptosis, angiogenesis, and invasion were examined. Moreover, the effects of FTY720 on tumor growth were evaluated using a patient-derived xenograft (PDX) model of cervical cancer. Immunohistochemical analysis revealed that expression of SPHK1 was significantly increased in cervical cancer compared with normal tissues. SPHK1 expression was significantly associated with tumor size, invasion depth, FIGO stage, lymph node metastasis, and lymphovascular invasion. Patients with high SPHK1 expression had lower overall survival and recurrence-free survival rates than those with low expression. Treatment with SPHK inhibitors significantly reduced viability and increased apoptosis in cervical cancer cells. Furthermore, FTY720 significantly decreased in vivo tumor weight in the PDX model of cervical cancer. We provide the first convincing evidence that SPHK1 is involved in tumor development and progression of cervical cancer. Our data suggest that SPHK1 might be a potential prognostic marker and therapeutic target for the treatment of cervical cancer.     

MET is a potential target for use in combination therapy with EGFR inhibition in triple‐negative/basal‐like breast cancer

MET, a cell surface receptor for hepatocyte growth factor, is involved in the development of triple‐negative/basal‐like breast cancer (TNBC/BLBC). However, its utility as a therapeutic target in this subtype of breast cancer is poorly understood. To evaluate MET fully as a potential therapeutic target for TNBC/BLBC, we investigated the relationship between MET expression and clinical outcomes of patients with breast cancer and the functional effect of MET inhibition. Using automated immunohistochemistry (Ventana), we analyzed MET expression in 924 breast cancer patients with relevant clinicopathologic parameters. BLBC showed the strongest relationship with MET expression (57.5%, p < 0.001). High expression of MET in breast cancer resulted in poor overall survival (p = 0.001) and disease‐free survival (DFS, p = 0.010). MET expression was relatively high in TNBC cell lines, and the silencing of MET via small interfering RNA reduced cell proliferation and migration. We observed reduced TNBC cell viability after treatment with the MET inhibitor PHA‐665752. In the most drug‐resistant cell line, MDA‐MB‐468, which showed elevated epidermal growth factor receptor (EGFR) expression, silencing of EGFR resulted in increased sensitivity to PHA‐665752 treatment. We confirmed that PHA‐665752 synergizes with the EGFR inhibitor erlotinib to decrease the viability of MDA‐MB‐468 cells. TNBC patients coexpressing MET and EGFR showed significantly worse DFS than that in patients expressing EGFR alone (p = 0.021). Our findings strongly suggest that MET may be a therapeutic target in TNBC and that the combined therapy targeting MET and EGFR may be beneficial for the treatment of TNBC/BLBC patients.     

Toll样受体信号通路作为结直肠癌潜在治疗靶点的研究进展

Toll样受体(Toll-like receptors,TLRs)信号通路参与激活固有免疫和适应性免疫应答,在结直肠癌的发生发展中发挥重要作用。TLRs信号通路失调可导致上皮出血、慢性炎症以及促进结直肠癌的发展。现在有大量证据表明靶向这一途径将有益于结直肠癌的治疗,如卡介苗、单磷酰脂A、咪喹莫特等现已应用于临床。本文综述了目前有关TLRs在肿瘤发展中的不同功能及其在结直肠癌治疗中的应用。     

KIFC1 is a novel potential therapeutic target for breast cancer

Kinesin-like protein KIFC1, a normally nonessential kinesin motor, plays a critical role in centrosome clustering in cancer cells and is essential for the survival of cancer cells. Herein, we reported that KIFC1 expression is up-regulated in breast cancer, particularly in estrogen receptor negative, progesterone receptor negative and triple negative breast cancer, and is not associated with epidermal growth factor receptor 2 status. In addition, KIFC1 is highly expressed in all 8 tested human breast cancer cell lines, but is absent in normal human mammary epithelial cells and weakly expressed in 2 human lung fibroblast lines. Moreover, KIFC1 silencing significantly reduced breast cancer cell viability. Finally, we found that PJ34, a potent small molecule inhibitor of poly(ADP-ribose) polymerase, suppressed KIFC1 expression and induced multipolar spindle formation in breast cancer cells, and inhibited cell viability and colony formation within the same concentration range, suggesting that KIFC1 suppression by PJ34 contributes to its anti-breast cancer activity. Together, these results suggest that KIFC1 is a novel promising therapeutic target for breast cancer.     

Connective tissue growth factor as a novel therapeutic target in high grade serous ovarian cancer

Ovarian cancer is the most common cause of death among women with gynecologic cancer. We examined molecular profiles of fibroblasts from normal ovary and high-grade serous ovarian tumors to identify novel therapeutic targets involved in tumor progression. We identified 2,300 genes that are significantly differentially expressed in tumor-associated fibroblasts. Fibroblast expression of one of these genes, connective tissue growth factor (CTGF), was confirmed by immunohistochemistry. CTGF protein expression in ovarian tumor fibroblasts significantly correlated with gene expression levels. CTGF is a secreted component of the tumor microenvironment and is being pursued as a therapeutic target in pancreatic cancer. We examined its effect in in vitro and ex vivo ovarian cancer models, and examined associations between CTGF expression and clinico-pathologic characteristics in patients. CTGF promotes migration and peritoneal adhesion of ovarian cancer cells. These effects are abrogated by FG-3019, a human monoclonal antibody against CTGF, currently under clinical investigation as a therapeutic agent. Immunohistochemical analyses of high-grade serous ovarian tumors reveal that the highest level of tumor stromal CTGF expression was correlated with the poorest prognosis. Our findings identify CTGF as a promoter of peritoneal adhesion, likely to mediate metastasis, and a potential therapeutic target in high-grade serous ovarian cancer. These results warrant further studies into the therapeutic efficacy of FG-3019 in high-grade serous ovarian cancer.     

High MET expression is an adverse prognostic factor in patients with triple-negative breast cancer

Background:

The mesenchymal–epithelial transition (MET) pathway is frequently altered in tumours. The purpose of our study was to determine the prognostic value of tumour MET expression levels in patients with triple-negative breast cancer (TNBC), in order to strengthen the rationale for targeted therapy of TNBC using MET inhibitors.

Methods:

We determined expression of MET in formalin-fixed paraffin-embedded surgical specimens of TNBC by immunohistochemistry. Recurrence-free and overall survival was analysed with Cox models adjusted for clinical and pathological factors.

Results:

Immunostaining for MET was classified as high in 89 of 170 (52%) tumours. MET expression was more frequently observed in G3 carcinomas (P=0.02) but was not significantly associated to any of the other clinical or pathological parameters. High MET expression predicted shorter survival of the patients. Multivariate Cox proportional hazards regression analyses identified MET to be an independent prognostic factor for recurrence (adjusted hazard ratio (HR) for recurrence 3.43; 95% confidence interval (CI) 1.65–7.12; P=0.001) and death (adjusted HR for death 3.74; 95% CI 1.65–8.46; P=0.002).

Conclusion:

These results provide further evidence that the MET pathway could be exploited as a target for TNBC.     

Fluorescent imaging of high‐grade bladder cancer using a specific antagonist for chemokine receptor CXCR4

We previously reported that the expression of CXC chemokine receptor‐4 (CXCR4) was upregulated in invasive bladder cancers and that the small peptide T140 was a highly sensitive antagonist for CXCR4. In this study, we identified that CXCR4 expression was induced in high‐grade superficial bladder tumors, including carcinoma in situ and invasive bladder tumors. To visualize the bladder cancer cells using urinary sediments from the patients and chemically induced mouse bladder cancer model, a novel fluorescent CXCR4 antagonist TY14003 was developed, that is a T140 derivative. TY14003 could label bladder cancer cell lines expressing CXCR4, whereas negative‐control fluorescent peptides did not label them. When labeling urinary sediments from patients with invasive bladder cancer, positive‐stained cells were identified in all patients with bladder cancer and positive urine cytology but not in controls. Although white blood cells in urine were also labeled with TY14003, they could be easily discriminated from urothelial cells by their shape and size. Finally, intravesical instillation of TY14003 into mouse bladder, using N‐butyl‐N‐(4‐hydroxybutyl) nitrosamine (BBN)‐induced bladder cancer model, demonstrated that fluorescent signals were detected in the focal areas of bladder of all mice examined at 12 weeks of BBN drinking by confocal microscopy and fluorescent endoscopy. On the contrary, all the normal bladders were found to be negative for TY14003 staining. In conclusion, these results indicate that TY14003 is a promising diagnostic tool to visualize small or flat high‐grade superficial bladder cancer.     

HLA-B*07 is a high risk allele for familial cervical cancer

Aim: The purpose of this study was to investigate 50 women from eight families with familial cervical cancer in Wufeng County, Hubei Province, China, a region with a high incidence of cervical cancer. Eighty-nine healthy women, of similar age, location and ethnicity, were selected as a control group. Methods: Blood samples were collected from both groups, and HLA-A, HLA-B, and HLA-DRB1 genotypes were profiled with the Multi-Analyte Profiling system (xMAP) (Luminex HLA-SSO) using a WAKFlow HLA typing kit. Results were analyzed with Luminex HLA typing software and showed good stability, reproducibility and specificity. Results: We found several high risk alleles in women with familial cervical cancer, that associated with the highest risk being HLA-B*07 (OR = 8.7, 95% CI = 1.8-41.1). Conclusions: HLA-B*07 is a high risk allele for cervical cancer, and has strong potential for use as a molecular biomarker.     

MET receptor tyrosine kinase as a therapeutic anticancer target

Tyrosine kinases are frequently deregulated in cancer either by constitutive activation, mutation, or over-expression. Though they are often associated with an aggressive phenotype they are also proving to be a druggable target. Activation of the MET receptor tyrosine kinase promotes cell proliferation, scattering, invasion, survival, and angiogenesis. Deregulation of MET promotes tumor formation, growth, progression, metastasis, and therapeutic resistance. Because MET is a player in so many aspects of cancer development and progression, it is a strong candidate for targeted therapy. Numerous agents have been developed that are able to target MET expression and/or function and are the focus of this review.     

HER2 expression in cervical cancer as a potential therapeutic target

Background  

Trastuzumab, a humanized monoclonal antibody against the HER2 receptor is currently being used in breast and other tumor types. Early studies have shown that a variable proportion of cervical carcinoma tumors overexpress the HER2 receptor as evaluated by diverse techniques and antibodies. Currently it is known that a tumor response to trastuzumab strongly correlates with the level of HER2 expression evaluated by the Hercep Test, thus, it seems desirable to evaluate the status of expression of this receptor using the FDA-approved Hercep Test and grading system to gain insight in the feasibility of using trastuzumab in cervical cancer patients.     

Sortilin‐related receptor is a druggable therapeutic target in breast cancer

In breast cancer, the currently approved anti‐receptor tyrosine‐protein kinase erbB‐2 (HER2) therapies do not fully meet the expected clinical goals due to therapy resistance. Identifying alternative HER2‐related therapeutic targets could offer a means to overcome these resistance mechanisms. We have previously demonstrated that an endosomal sorting protein, sortilin‐related receptor (SorLA), regulates the traffic and signaling of HER2 and HER3, thus promoting resistance to HER2‐targeted therapy in breast cancer. This study aims to assess the feasibility of targeting SorLA using a monoclonal antibody. Our results demonstrate that anti‐SorLA antibody (SorLA ab) alters the resistance of breast cancer cells to HER2 monoclonal antibody trastuzumab in vitro and in ovo. We found that SorLA ab and trastuzumab combination therapy also inhibits tumor cell proliferation and tumor cell density in a mouse xenograft model of HER2‐positive breast cancer. In addition, SorLA ab inhibits the proliferation of breast cancer patient‐derived explant three‐dimensional cultures. These results provide, for the first time, proof of principle that SorLA is a druggable target in breast cancer.