Identification of molecular targets associated with transformed diffuse large B cell lymphoma using highly purified tumor cells

Abstract

Follicular lymphoma (FL) frequently transforms into the more aggressive diffuse large B cell lymphoma (DLBCL‐tr), but no protein biomarkers have been identified for predictive or early diagnosis. Gene expression analyses have identified genes changing on transformation but have failed to be reproducible in different studies, reflecting the heterogeneity within the tumor tissue and between tumor samples. Gene expression analyses on Affymetrix Human Genome U133 Plus 2.0 arrays were performed, using flow cytometry sorted tumor cells derived from FL and transformed DLBCL. To identify molecular targets associated with the transformation, subsequent immunohistochemistry (IHC) analyses of the corresponding proteins were performed. Using highly purified cells, this study identified 163 genes, which were significantly deregulated during the transformation in a majority of cases. Among the upregulated transcripts, 13 genes were selected for validation using IHC, based on the availability of commercial antibodies, and galectin‐3 and NEK2 proteins specifically identify DLBCL‐tr, when compared with FL. We demonstrate that by purifying tumor cells through cell sorting, thereby reducing the heterogeneity due to infiltrating cells, it was possible to identify distinct differences between tumor entities rather than variations due to cellular composition. Galectin‐3 and NEK2 both identified a subgroup of DLBCL‐tr, and the function of these protein markers also suggests a biological role in the transformation process. Am. J. Hematol. 2009. © 2009 Wiley‐Liss, Inc.

Targeting NEK2 attenuates glioblastoma growth and radioresistance by destabilizing histone methyltransferase EZH2

“…NEK2 overexpression has been recognized in various cancers, including breast cancer, lymphoma, testicular seminomas, lung cancer, and colorectal cancer, and it has been shown to correlate with an aggressive phenotype and poor prognoses for these cancers (11,(31)(32)(33)(34). A recent study reported that NEK2 silencing by shRNAs reduces tumor cell progression by interference with chromosomal segregation in human breast cancer cell lines in vitro and in fat pad xenograft mouse models, leading to aneuploidy and subsequent cell death (35).…”

Galectin-3 binds to CD45 on diffuse large B-cell lymphoma cells to regulate susceptibility to cell death

“…Gal-3 has been reported to have antiapoptotic activity in several types of tumor cells, including DLBCL cells [6][7][8] ; however, removal of cell-surface gal-3 alone with 75 g/mL GCS-100 did not decrease cell viability (Figure 2A). Thus, we asked whether removal of cell-surface gal-3 would sensitize DLBCL cells to apoptosis induced by other agents.…”

Identification of uniquely expressed transcription factors in highly purified B‐cell lymphoma samples

“…All specimens in this study were diagnosed according to the World Health Organization (WHO) criteria [16] including; FL, n 5 12; DLBCL-tr, n 5 6; DLBCL-GC, n 5 7; DLBCL-nonGC, n 5 10; MCL, n 5 12; CLL, n 5 15; L-MCL, n 5 6 and HCL, n 5 10. Of note, some samples (FL, n 5 12; DLBCL-tr, n 5 6) have been analyzed previously in a study where the transformation from FL to DLBCL-tr was examined [17]. Freshly frozen tumor cell suspensions were collected from the biobank at the Department of Pathology, Uppsala University Hospital (Uppsala, Sweden) (FL, DLBCL, MCL, CLL, HCL), and from the biobank at Rigshospitalet (Copenhagen, Denmark) (L-MCL).…”

“…The labeled cRNA was hybridized to the Human Genome U133 Plus 2.0 arrays containing 50,000 transcripts (Affymetrix). This complete procedure is described in detail previously [17,20]. All arrays included in the study passed the initial quality control, including comparison of scaling factors, background, noise, and GAPDH expression with threshold values defined by Affymetrix.…”