XMD8-92 inhibits pancreatic tumor xenograft growth via a DCLK1-dependent mechanism

DCLK1 is detectable in plasma of patients with Barrett's esophagus and esophageal adenocarcinoma

BACKGROUND

Doublecortin-like kinase 1 (DCLK1), a putative tumor stem cell marker has been shown to be highly expressed in the stromal and epithelial compartments in colon and pancreatic cancer as well as Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC).

AIM

To prospectively investigate whether the immunohistochemical expression of DCLK1 was associated with detectable DCLK1 plasma expression in patients with existing BE and EAC.

METHODS

Immunohistochemistry was performed on paraffin-embedded sections using DCLK1 antibody and scored based on staining intensity and tissue involvement. Purified human plasma samples were subjected to Western blot and ELISA analysis.

RESULTS

Forty (40) patients were enrolled: 10 controls (normal endoscopy) and 30 with BE/EAC (13 nondysplastic BE [NDBE], 9 dysplastic BE [DBE] and 8 EAC). Mean epithelial DCLK1 staining was as follows: controls = 0.11, NDBE = 3.83, DBE = 6.0, EAC = 7.17. Mean stromal DCLK1 staining was as follows: NDBE = 5.83, DBE = 5.375, EAC = 10.83. DCLK1 was detected by plasma Western blot in 1 control and in all patients with BE/EAC p < 0.0005. Plasma DCLK1 was elevated by ELISA in EAC compared to other groups, p < 0.05.

CONCLUSIONS

Increased expression of DCLK1 was observed in the epithelium, stroma and plasma of patients with BE/EAC. Furthermore, the presence of detectable DCLK1 in plasma of BE/EAC patients may provide a less invasive, detection tool in those patients as well as represent a novel molecular marker distinguishing between normal esophageal mucosa and BE or EAC.

Regulation of miRNAs by agents targeting the tumor stem cell markers DCLK1, MSI1, LGR5, and BMI1

Gastrointestinal cancers such as colorectal, pancreatic, liver, gastric, and esophageal, are the most common forms of malignant cancers. MicroRNAs (miRNA) play important role in regulating gastrointestinal cancer progress either as potent oncogenes or tumor suppressors. In this report, we will discuss the importance of several tumor suppressors involved in colon or pancreatic cancer. Some recent studies on tumor stem cells and regulation of these miRNAs via agents targeting the tumor stem cell markers doublecortin-like kinase 1 (DCLK1), Musashi-1 (MSI1), polycomb protein BMI1, and WNT genes (LGR5 and ASCL2) will also be discussed. Agents such as siRNA/shRNA, small molecule kinase inhibitors, and general herbal drugs (curcumin) targeting these tumor stem cell markers and tumor suppressor miRNAs could be the perfect therapeutic agents for the treatment of these cancers.

Differential Expression of MicroRNAs in Tissues and Plasma Co-exists as a Biomarker for Pancreatic Cancer

OBJECTIVE

Pancreatic cancer (PC) is a lethal disease with disappointing results from current treatment modalities, suggesting that novel therapeutic strategies are urgently needed. Since microRNAs (miRNAs) are important player in biology, the clinical utility of miRNAs for designing novel therapeutics is an active area of research. The objective of the present study was to examine differentially expressed miRNAs between normal and tumor tissues, and in plasma samples obtained from PC patients, chronic pancreatitis (CP) patients and healthy subjects (HC).

MATERIAL AND METHODS

The miRNA expression profiling using formalin-fixed paraffin embedded (FFPE) tissues from normal and tumor specimens was accomplished using miRBase version 19 (LC Sciences, Houston, TX, USA). Quantitative real-time PCR (qRT-PCR) was subsequently performed in individual samples for 7 selected miRNAs. In addition, qRT-PCR was also performed for assessing the expression of 8 selected miRNAs in plasma samples.

RESULTS

A significant difference in the expressions of miR-21, miR-205, miR-155, miR-31, miR-203, miR-214 and miR-129-2 were found in tumor tissue samples. Lower expression of miR-214 was found to be associated with better overall survival. We also observed differential expression of 8 miRNAs in plasma samples of CP and PC patients compared to HC. Interestingly, over expression of miR-21, and miR-31 was noted in both tumor tissues and in the plasma.

CONCLUSION

We found deregulated expression of miRNAs that could distinguish normal from PC in two different types of samples (tissues and plasma). Interestingly, lower expression of miR-214 was found to be associated with better overall survival. Although not statistically significant, we also observed higher expression of let-7a and lower expression of miR-508 to be associated with overall better survival. We conclude that our study nicely lays the foundation for detailed future investigations for assessing the role of these miRNAs in the pathology of pancreatic cancer.