Enolase-1 is a therapeutic target in endometrial carcinoma

ENO1 plays a paradoxical role in driving the pathogenesis of tumors. However, the clinical significance of ENO1 expression remains unclear and its function and modulatory mechanisms have never been reported in endometrial carcinoma (EC). In this study, ENO1 silencing significantly reduced cell glycolysis, proliferation, migration, and invasion in vitro, as well as tumorigenesis and metastasis in vivo by modulating p85 suppression. This in turn mediated inactivation of PI3K/AKT signaling and its downstream signals including glycolysis, cell cycle progression, and epithelial-mesenchymal transition (EMT)-associated genes. These effects on glycolysis and cell growth were not observed after ENO1 suppression in normal human endometrial epithelial cells (HEEC). Knocking down ENO1 could significantly enhance the sensitivity of EC cells to cisplatin (DDP) and markedly inhibited the growth of EC xenografts in vivo. In clinical samples, EC tissues exhibited higher expression levels of ENO1 mRNA and protein compared with normal endometrium tissues. Patients with higher ENO1 expression had a markedly shorter overall survival than patients with low ENO1 expression. We conclude that ENO1 favors carcinogenesis, representing a potential target for gene-based therapy.     

BRAF mutation in papillary thyroid carcinoma

The BRAF gene has been found to be activated by mutation in human cancers, predominantly in malignant melanoma. We tested 476 primary tumors, including 214 lung, 126 head and neck, 54 thyroid, 27 bladder, 38 cervical, and 17 prostate cancers, for the BRAF T1796A mutation by polymerase chain reaction (PCR)-restriction enzyme analysis of BRAF exon 15. In 24 (69%) of the 35 papillary thyroid carcinomas examined, we found a missense thymine (T)-->adenine (A) transversion at nucleotide 1796 in the BRAF gene (T1796A). The T1796A mutation was detected in four lung cancers and in six head and neck cancers but not in bladder, cervical, or prostate cancers. Our data suggest that activating BRAF mutations may be an important event in the development of papillary thyroid cancer.     

Doublecortin-like kinase 1 is a therapeutic target in squamous cell carcinoma

Doublecortin like kinase 1 (DCLK1) plays a crucial role in several cancers including colon and pancreatic adenocarcinomas. However, its role in squamous cell carcinoma (SCC) remains unknown. To this end, we examined DCLK1 expression in head and neck SCC (HNSCC) and anal SCC (ASCC). We found that DCLK1 is elevated in patient SCC tissue, which correlated with cancer progression and poorer overall survival. Furthermore, DCLK1 expression is significantly elevated in human papilloma virus negative HNSCC, which are typically aggressive with poor responses to therapy. To understand the role of DCLK1 in tumorigenesis, we used specific shRNA to suppress DCLK1 expression. This significantly reduced tumor growth, spheroid formation, and migration of HNSCC cancer cells. To further the translational relevance of our studies, we sought to identify a selective DCLK1 inhibitor. Current attempts to target DCLK1 using pharmacologic approaches have relied on nonspecific suppression of DCLK1 kinase activity. Here, we demonstrate that DiFiD (3,5-bis [2,4-difluorobenzylidene]−4-piperidone) binds to DCLK1 with high selectivity. Moreover, DiFiD mediated suppression of DCLK1 led to G2/M arrest and apoptosis and significantly suppressed tumor growth of HNSCC xenografts and ASCC patient derived xenografts, supporting that DCLK1 is critical for SCC growth.     

LAT1 is a putative therapeutic target in endometrioid endometrial carcinoma

l ‐type amino acid transporters (LAT1‐4) are expressed in various cancer types and are involved in the uptake of essential amino acids such as leucine. Here we investigated the expression of LAT1‐4 in endometrial adenocarcinoma and evaluated the contribution of LATs to endometrial cancer cell growth. Analysis of human gene expression data showed that all four LAT family members are expressed in endometrial adenocarcinomas. LAT1 was the most highly expressed, and showed a significant increase in both serous and endometrioid subtypes compared to normal endometrium. Endometrioid patients with the highest LAT1 levels exhibited the lowest disease‐free survival. The pan‐LAT inhibitor BCH led to a significant decrease in cell growth and spheroid area in four endometrial cancer cell lines tested in vitro. Knockdown of LAT1 by shRNA inhibited cell growth in HEC1A and Ishikawa cells, as well as inhibiting spheroid area in HEC1A cells. These data show that LAT1 plays an important role in regulating the uptake of essential amino acids such as leucine into endometrial cancer cells. Increased ability of BCH compared to LAT1 shRNA at inhibiting Ishikawa spheroid area suggests that other LAT family members may also contribute to cell growth. LAT1 inhibition may offer an effective therapeutic strategy in endometrial cancer patients whose tumours exhibit high LAT1 expression.     

Mevalonate pathway is a therapeutic target in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common lethal tumors in the world. Thus, it is very urgent to develop new therapeutic targets against this disease. The mevalonate (MVA) pathway, paced by its rate-limiting enzyme, hydroxymethylglutaryl coenzyme A reductase, is required for the generation of several fundamental end products including cholesterol and isoprenoids. The function of the MVA pathway in ESCC has not been investigated. In this study, it was found that the MVA pathway was upregulated in ESCC clinical samples. Statin, the inhibitor of the MVA pathway, exerted potent cytotoxicity against human ESCC cells by inhibiting cell growth and proliferation, while it exerted lesser effects on non-tumorigenic SHEE cells. Further study revealed that statin could potently induce cell apoptosis and cell cycle arrest and also dose-dependently inhibit the growth of xenograft tumors in nude mice. With regard to the molecular mechanism, statin treatment was related to decreased extracellular signal-regulated kinase activation and proliferating cell nuclear antigen, cyclin D1 expression, and increased cleavage of poly(ADP-ribose) polymerase. Taken together, our findings suggest that the MVA pathway plays an important role in the progression of ESCC by modulating cell growth and statin might be a potential therapeutic agent in ESCC.     

EGFR is a potential therapeutic target for highly glycosylated and aggressive pancreatic neuroendocrine neoplasms

pNENs are relative indolent tumors with heterogeneous clinical presentation at diagnosis. It is important to establish aggressive subgroups of pNENs and identify potential therapeutic targets. Patients with pNEN (322 cases) were included to examine the association between glycosylation biomarkers and clinical/pathological traits. The molecular and metabolic features stratified by glycosylation status were assessed by RNA-seq/whole exome sequencing and immunohistochemistry. A considerable proportion of patients had elevated glycosylation biomarkers (carbohydrate antigen [CA] 19-9, 11.9%; CA125, 7.5%; carcinoembryonic antigen [CEA], 12.8%). CA19-9 (hazard ratio [HR] = 2.26, P = .019), CA125 (HR = 3.79, P = .004) and CEA (HR = 3.16, P = .002) were each independent prognostic variables for overall survival. High glycosylation group, defined as pNENs with elevated level of circulating CA19-9, CA125 or CEA, accounted for 23.4% of all pNENs. High glycosylation (HR = 3.14, P = .001) was an independent prognostic variable for overall survival and correlated with G3 grade (P < .001), poor differentiation (P = .001), perineural invasion (P = .004) and distant metastasis (P < .001). Epidermal growth factor receptor (EGFR) was enriched in high glycosylation pNENs using RNA-seq. EGFR was expressed in 21.2% of pNENs using immunohistochemistry and associated with poor overall survival (P = .020). A clinical trial focusing on EGFR expressed pNENs was initiated (NCT05316480). Thus, pNEN with aberrant glycosylation correlates with a dismal outcome and suggests potential therapeutic target of EGFR.     

Locally aggressive differentiated thyroid carcinoma

Local infiltration of adjacent anatomic structures and soft tissues of the neck from well-differentiated carcinoma of the thyroid gland is a relatively infrequent occurrence. We report our experience with 21 such cases seen in our department over the past 20 years. All patients were treated by total thyroidectomy and total or partial excision of the infiltrated adjacent structures. Papillary carcinoma was the most frequent type of primary tumor seen. Following the definitive surgery, all patients were scanned with radioactive iodine (131I). In case of isotope entrapment, a curative dose 131I was given. All patients in our series were required to receive thyroid hormone replacement. Four patients died as a result of their disease. Uncontrolled local disease and distant metastases were present at the time of death. Three patients died of unrelated causes. Two-thirds of the patients are still alive (from 1 to 19 years after the treatment).     

Axl receptor tyrosine kinase is a potential therapeutic target in renal cell carcinoma

Background:

Axl plays multiple roles in tumourigenesis in several cancers. Here we evaluated the expression and biological function of Axl in renal cell carcinoma (RCC).

Methods:

Axl expression was analysed in a tissue microarray of 174 RCC samples by immunostaining and a panel of 11 normal tumour pairs of human RCC tissues by western blot, as well as in RCC cell lines by both western blot and quantitative PCR. The effects of Axl knockdown in RCC cells on cell growth and signalling were investigated. The efficacy of a humanised Axl targeting monoclonal antibody hMAb173 was tested in histoculture and tumour xenograft.

Results:

We have determined by immunohistochemistry (IHC) that Axl is expressed in 59% of RCC array samples with moderate to high in 20% but not expressed in normal kidney tissue. Western blot analysis of 11 pairs of tumour and adjacent normal tissue show high Axl expression in 73% of the tumours but not normal tissue. Axl is also expressed in RCC cell lines in which Axl knockdown reduces cell viability and PI3K/Akt signalling. The Axl antibody hMAb173 significantly induced RCC cell apoptosis in histoculture and inhibited the growth of RCC tumour in vivo by 78%. The hMAb173-treated tumours also had significantly reduced Axl protein levels, inhibited PI3K signalling, decreased proliferation, and induced apoptosis.

Conclusions:

Axl is highly expressed in RCC and critical for RCC cell survival. Targeting Axl is a potential approach for RCC treatment.     

HOTAIR is a therapeutic target in glioblastoma

HOTAIR is a negative prognostic factor and is overexpressed in multiple human cancers including glioblastoma multiform (GBM). Survival analysis of Chinese Glioma Genome Atlas (CGGA) patient data indicated that high HOTAIR expression was associated with poor outcome in GBM patients. NLK (Nemo-like kinase), a negative regulator of the β-catenin pathway, was negatively correlated with HOTAIR expression. When the β-catenin pathway was inhibited, GBM cells became susceptible to cell cycle arrest and inhibition of invasion. Introduction of the HOTAIR 5′ domain in human glioma-derived astrocytoma induced β-catenin. An intracranial animal model was used to confirm that HOTAIR depletion inhibited GBM cell migration/invasion. In the orthotopic model, HOTAIR was required for GBM formation in vivo. In summary, HOTAIR is a potential therapeutic target in GBM.     

B-RAF is a therapeutic target in melanoma

B-RAF is a serine/threonine-specific protein kinase that is mutated in approximately 70% of human melanomas. However, the role of this signalling molecule in cancer is unclear. Here, we show that ERK is constitutively activated in melanoma cells expressing oncogenic B-RAF and that this activity is required for proliferation. B-RAF depletion by siRNA blocks ERK activity, whereas A-RAF and C-RAF depletion do not affect ERK signalling. B-RAF depletion inhibits DNA synthesis and induces apoptosis in three melanoma cell lines and we show that the RAF inhibitor BAY43-9006 also blocks ERK activity, inhibits DNA synthesis and induces cell death in these cells. BAY43-9006 targets B-RAF signalling in vivo and induces a substantial growth delay in melanoma tumour xenografts. Our data demonstrate that oncogenic B-RAF activates ERK signalling, induces proliferation and protects cells from apoptosis, demonstrating that it is an important therapeutic target and thus provides novel strategies for clinical management of melanoma and other cancers.     

Overexpression of miR-221 is associated with aggressive clinicopathologic characteristics and the BRAF mutation in papillary thyroid carcinomas

Correlation between clinicopathogenetic features and the expression of specific miRNAs is unclear in papillary thyroid carcinoma (PTC). We therefore sought to assess whether miR-221 was associated with aggressive clinicopathologic characteristics and the BRAF mutation. We studied the expression levels of miR-221 using northern blot quantitated by scion image in 51 cases of PTCs. The status of BRAF of PTCs was analyzed through direct DNA sequencing. Mann?CWhitney U test was used to analyze different expression of miR-221 in PTCs with distinct clinicopathogenetic characteristics including gender, age, tumor size, multifocality, extrathyroidal invasion, disease stages, node metastasis, and BRAF status. Compared with the normal thyroid tissues, the relative expression of miR-221 in tumor tissues was significantly upregulated (p?<?0.001). Overexpression of miR-221 was significantly associated with extrathyroidal invasion (p?=?0.001), lymph node metastasis (p?=?0.046), advanced disease stages III?CIV (p?=?0.001), and the BRAF mutation (p?=?0.014). While among BRAF wild tumors, miR-221 was only associated with extarthyroidal invasion, it showed strong association with all above aggressive features among BRAF mutation tumors. MiR-221 may be of potential importance in determining the aggressive properties of PTCs including the BRAF mutation, and it may further refine the risk stratification by BRAF mutation in PTCs.     

BRAF,a target in melanoma

The successful translation of therapies targeting signal‐transduction pathways that are activated by oncogenes has provided a model for molecularly targeted therapy, and the identification of mutations in v‐raf murine sarcoma viral oncogene homolog B1 (BRAF), a serine/threonine kinase, has turned the attention of the melanoma field toward this concept. The current review indicated that BRAF represents an important target in cancer, in part because it is present in 7% of all cancers and also because it represents the first intracellular signaling molecule that is activated by point mutations for which single‐agent therapy appears to have efficacy. Therapy for advanced melanoma has progressed slowly over the past 3 decades, although significant advances have been made in other cancers with the application of cytotoxic chemotherapy and targeted therapies. However, in melanoma, cytotoxic chemotherapies have severe limits, chemotherapy does not convincingly improve on the natural history of metastatic disease and has no role in the adjuvant setting, and cytokine therapy may have a niche in both the adjuvant and metastatic settings but confers only a modest benefit to a small proportion of patients at the cost of severe toxicity. Thus, there are few other cancers in which completely novel therapies are so highly prioritized in clinical research. Understanding network of signal‐transduction pathways and how that network may adapt to BRAF inhibition or mitogen‐activated protein kinase kinase inhibition will point to the next generation of clinical trials investigating rational combination regimens. The current investigations in melanoma will create a set of hypotheses to be tested in each cancer that harbors BRAF mutations. Cancer 2010. © 2010 American Cancer Society.     

Increased fatty acid synthase is a therapeutic target in mesothelioma.

Many common human cancer tissues express high levels of fatty acid synthase (FAS), the primary enzyme for the synthesis of fatty acids, and the differential expression of FAS between normal and neoplastic tissues has led to the consideration of FAS as a target for anticancer therapy. To investigate the potential of targeting FAS for the treatment of pleural mesothelioma, we first determined whether FAS is overexpressed in human mesothelioma. By immunohistochemistry, we found 22 of 30 human mesothelioma tissue samples tested to express significantly increased levels of FAS compared with normal tissues, including mesothelium. To further explore FAS as a therapeutic target in mesothelioma, we established a nude mouse xenograft model for human mesothelioma using the H-Meso cell line. The i.p. xenografts of this cell line have high levels of FAS expression and fatty acid synthesis pathway activity and grow along mesothelial surfaces in a manner similar to the growth pattern of human mesothelioma. Growth of these tumor xenografts was essentially abolished in mice treated with weekly i.p. injections of C75, a synthetic, small molecule inhibitor of FAS, at levels that resulted in no significant systemic toxicity except for reversible weight loss. These results suggest that FAS may be an effective target for pharmacological therapy in a high proportion of human mesotheliomas.     

PDGFR-A is a therapeutic target in alveolar rhabdomyosarcoma

Alveolar rhabdomyosarcoma is an aggressive skeletal muscle cancer of childhood. Our initial studies of rhabdomyosarcoma gene expression for patients enrolled in a national clinical trial suggested that platelet-derived growth factor receptor A (PDGFR-A) may be a mediator of disease progression and metastasis. Using our conditional mouse tumor models that authentically recapitulate the primary mutations and metastatic progression of alveolar rhabdomyosarcomas in humans, we found by immunoblotting and immunokinase assays that PDGFR-A and its downstream effectors, mitogen-activated protein kinase and Akt, were highly activated in both primary and metastatic tumors. Inhibition of PDGFR-A by RNA interference, small molecule inhibitor or neutralizing antibody had a dramatic effect on tumor cell growth both in vitro and in vivo, although resistance evolved in one-third of tumors. These results establish proof-of-principal for PDGFR-A as a therapeutic target in alveolar rhabdomyosarcoma.     

Adrenomedullin is a therapeutic target in colorectal cancer

The KRAS oncogene influences angiogenesis, metastasis and chemoresistance in colorectal cancers (CRCs), and these processes are all enhanced in hypoxic conditions. To define functional activities of mutant KRAS in a hypoxic microenvironment, we first performed cDNA microarray experiments in isogenic DKs5 and DKO3 colon cancer cell lines that differ only by their expression of mutant KRAS (K‐ras^D13). Adrenomedullin (ADM) was identified as one of the most significantly upregulated genes in DKs5 cells that express the KRAS oncogene in hypoxia (3.2‐fold, p = 1.47 × 10^?5). Ectopic expression of mutant KRAS (K‐ras^V12) in Caco‐2 cells (K‐ras^WT) induced ADM, whereas selective knockdown of mutant KRAS alleles (K‐ras^D13 or K‐ras^V12) in HCT116, DLD1 and SW480 colon cancer cells suppressed the expression of ADM in hypoxia. Knockdown of ADM in colon tumor xenografts blocked angiogenesis and stimulated apoptosis, resulting in tumor suppression. Furthermore, ADM also regulated colon cancer cell invasion in vitro. Among 56 patients with CRC, significantly higher expression levels of ADM were observed in samples harboring a KRAS mutation. Collectively, ADM is a new target of oncogenic KRAS in the setting of hypoxia. This observation suggests that therapeutic targets may differ depending upon the specific tumor microenvironment.     

AMPK as a therapeutic target in renal cell carcinoma

AMPK is a cellular energy sensor that negatively regulates the mTOR signaling pathway. As mTOR plays critical roles in cell growth and tumorigenesis of renal cell carcinoma (RCC), we examined whether exogenous induction of AMPK activity exhibits inhibitory effects on growth and survival of renal cell carcinoma cells. Activation of AMPK by AICAR resulted in potent suppressive effects on RCC growth, while combinations of AICAR with statins were potent inducers of apoptosis in such cells. The effects of AICAR resulted from inhibition of mTOR and its effectors, resulting from induction of AMPK activity. Similar results on RCC cell growth were obtained when combinations of metformin with statins were examined. Importantly, studies to examine the effects of AICAR or metformin, alone or in combinations with statins, on anchorage-independent growth demonstrated potent suppressive effects on RCC tumorigenicity in vitro. Altogether, our studies demonstrate that AMPK plays critical regulatory roles in the regulation of growth of RCC cells and raise the prospect of future use of AMPK activators in the treatment of renal cell carcinoma in humans.