Probes for INS

 BACKGROUND:
 Expression of the colony-stimulating factor 1 (CSF1) gene is elevated in most tenosynovial giant-cell tumors. This observation has led to the discovery and clinical development of therapy targeting the CSF1 receptor (CSF1R).
 METHODS:
 Using x-ray co-crystallography to guide our drug-discovery research, we generated a potent, selective CSF1R inhibitor, PLX3397, that traps the kinase in the autoinhibited conformation. We then conducted a multicenter, phase 1 trial in two parts to analyze this compound. In the first part, we evaluated escalations in the dose of PLX3397 that was administered orally in patients with solid tumors (dose-escalation study). In the second part, we evaluated PLX3397 at the chosen phase 2 dose in an extension cohort of patients with tenosynovial giant-cell tumors (extension study). Pharmacokinetic and tumor responses in the enrolled patients were assessed, and CSF1 in situ hybridization was performed to confirm the mechanism of action of PLX3397 and that the pattern of CSF1 expression was consistent with the pathological features of tenosynovial giant-cell tumor.
 RESULTS:
 A total of 41 patients were enrolled in the dose-escalation study, and an additional 23 patients were enrolled in the extension study. The chosen phase 2 dose of PLX3397 was 1000 mg per day. In the extension study, 12 patients with tenosynovial giant-cell tumors had a partial response and 7 patients had stable disease. Responses usually occurred within the first 4 months of treatment, and the median duration of response exceeded 8 months. The most common adverse events included fatigue, change in hair color, nausea, dysgeusia, and periorbital edema; adverse events rarely led to discontinuation of treatment.
 CONCLUSIONS:
 Treatment of tenosynovial giant-cell tumors with PLX3397 resulted in a prolonged regression in tumor volume in most patients. (Funded by Plexxikon; ClinicalTrials.gov number, NCT01004861.).

Abstract

BACKGROUND:

Increasing evidence has demonstrated that mesenchymal stem cells (MSCs) play a role in the construction of tumor microenvironments. Co-culture between tumor cells and MSCs provides an easy and useful platform for mimicking tumor microenvironments and identifying the important members involved in tumor progress. The long non-coding RNAs (lncRNAs) have been shown to regulate different tumorigenic processes. In this study, we aimed to examine functional lncRNA deregulations associated with breast cancer malignancy instigated by MSC-MCF-7 co-culture.

METHODS:

The microarrays were used to profile the expression changes of lncRNAs in MCF-7 cells during epithelial-mesenchymal transition (EMT) induced by co-culture with MSCs. We found that an intergenic lncRNA KB-1732A1.1 (termed LincK, partly overlapped with GASL1) was significantly elevated. To investigate the biological function of LincK, the expression of EMT markers, cell migration, invasion, proliferation, and colony formation were evaluated in vitro and xenograft assay in nude mice were performed in vivo. Furthermore, we detected LincK expression in clinical samples using RNAscope™ technology and verified aberrant expression of LincK in breast cancer data sets from The Cancer Genome Atlas (TCGA) by bioinformatic analysis. The underlying mechanisms of LincK were investigated using mRNA microarray analyses, Western blot, RNA pull down, and RNA immunoprecipitation.

RESULTS:

LincK induced an EMT progress in breast cancer cells (BCC) MCF-7, MDA-MB-453, and MDA-MB-231. The depletion of LincK decreased the growth, migration, and invasion in BCC, whereas the overexpression of LincK exerted the opposite effects. Moreover, knockdown of LincK repressed tumorigenesis, and ectopic expression of LincK promoted tumor growth in MCF-7 xenograft model. LincK ablation in MDA-MB-231 cells dramatically impaired lung metastasis when incubated intravenously into nude mice. Further, LincK was frequently elevated in breast cancer compared with normal breast tissue in clinical samples. Mechanistically, LincK may share common miRNA response elements with PBK and ZEB1 and regulate the effects of miR-200 s.

CONCLUSION:

LincK plays a significant role in regulating EMT and tumor growth and could be a potential therapeutic target in breast cancer.

PD-L1 expression may be a predictive marker for anti-PD-1 therapeutic efficacy. No standard detection method of PD-L1 expression was available for advanced gastric cancer (AGC), which would be investigated in this study using RNA in situ hybridization and immunohistochemistry. Patients (N = 165) with AGC treated at Peking University Cancer Hospital from October 2008 to February 2013 were retrospectively studied. Tissue samples prior to chemotherapy were assessed for PD-L1 expression using RNA in situ hybridization (an RNAscope assay) and immunohistochemistry (IHC). The correlations of PD-L1 expression to patient characteristics and clinical outcomes were statistically analyzed. PD-L1 mRNA signals were located in tumor compartments or the mesenchyme in a brown dotted or clustered pattern, and PD-L1 mRNA expression in gastric cancer was heterogeneous. PD-L1-positive expressions were observed in 33.9% (56/165) and 35.1% (46/131) patients in mRNA level and protein level, respectively. A positive relationship was found between PD-L1 mRNA and PD-L1 protein, and compared to IHC, RNAscope assay could provide an intuitional and quantitative data with potential clinical application. No statistically significant differences occurred between PD-L1 expression and clinical response to chemotherapy, or survival. However, we found that PD-L1 expression was higher in intestinal type than in diffuse type. These findings suggested that the RNAscope assay may be a promising method for patient assessment in gastric cancer clinical trials, which would be illustrated in further study.

Hepatocellular carcinoma (HCC) represents the fifth and ninth cause of mortality among male and female cancer patients, respectively and typically arises on a background of a cirrhotic liver. HCC develops in a multi-step process, often encompassing chronic liver injury, steatosis and cirrhosis eventually leading to the malignant transformation of hepatocytes. Aberrant expression of the class I homeobox gene family (HOX), a group of genes crucial in embryogenesis, has been reported in a variety of malignancies including solid tumors. Among HOX genes, HOXA13 is most overexpressed in HCC and is known to be directly regulated by the long non-coding RNA HOTTIP. In this study, taking advantage of a tissue microarray containing 305 tissue specimens, we found that HOXA13 protein expression increased monotonically from normal liver to cirrhotic liver to HCC and that HOXA13-positive HCCs were preferentially poorly differentiated and had fewer E-cadherin-positive cells. In two independent cohorts, patients with HOXA13-positive HCC had worse overall survival than those with HOXA13-negative HCC. Using HOXA13 immunohistochemistry and HOTTIP RNA in situ hybridization on consecutive sections of 16 resected HCCs, we demonstrated that HOXA13 and HOTTIP were expressed in the same neoplastic hepatocyte populations. Stable overexpression of HOXA13 in liver cancer cell lines resulted in increased colony formation on soft agar and migration potential as well as reduced sensitivity to sorafenib in vitro. Our results provide compelling evidence of a role for HOXA13 in HCC development and highlight for the first time its ability to modulate response to sorafenib.