Anti-Human STMN1 (Phospho-Ser24) polyclonal antibody

In this communication, we present the phosphoproteome changes in an isogenic pair of colorectal cancer cell lines, viz., the poorly metastatic HCT-116 and the highly metastatic derivative E1, upon stathmin-1 (STMN1) knockdown. The aim was to better understand how the alterations of the phosphoproteins in these cells are involved in cancer metastasis. After the phosphopeptides were enriched using the TiO2 HAMMOC approach, comparative proteomics analysis was carried out using sequential window acquisition of all theoretical mass spectra-MS. Following bioinformatics analysis using MarkerView and OneOmics platforms, we identified a list of regulated phosphoproteins that may play a potential role in signaling, maintenance of cytoskeletal structure, and focal adhesion. Among these phosphoproteins, was the actin cytoskeleton regulator protein, vasodilator-stimulated phosphoprotein (VASP), where its change in phosphorylation status was found to be concomitant with STMN1-associated roles in metastasis. We further showed that silencing of stathmin-1 altered the expression, subcellular localization and phosphorylation status of VASP, which suggested that it might be associated with remodeling of the cell cytoskeleton in colorectal cancer metastasis.

STMN1 is a cytosolic phosphoprotein that not only participates in cell division, but also plays an important role in other microtubule-dependent processes, such as cell motility. Furthermore, STMN1 acts as a "relay protein" in several intracellular signaling pathways that influence cell growth and differentiation. Thus, STMN1 is likely to support cellular processes essential for tumor progression: survival and migration. Indeed, elevated STMN1 expression has been reported in various types of human malignancies and is correlated with poor prognosis in these human malignancies. However, the clinical and prognostic significance of STMN1 in pancreatic ductal adenocarcinoma (PDAC) remains unknown. Thus, we assessed STMN1 in PDAC in this retrospective study. We first examined STMN1 expression in PDAC tissues from 27 cases and matched adjacent non-cancerous tissues by quantitative polymerase chain reaction (PCR) and western blot analyses. Next, immunohistochemistry was used to evaluate STMN1 expression in 87 archived paraffin-embedded PDAC specimens. STMN1 mRNA and protein expression levels were to a large extent up-regulated in PDAC tissue compared with their adjacent non-cancerous tissues. Moreover, STMN1 expression was closely correlated with histological differentiation, lymphatic metastasis, and TNM stage (P = 0.023, 0.047, and 0.014, respectively). In addition, PDAC patients with higher STMN1 expression died sooner than those with lower STMN1 expression (P < 0.01). Multivariate analysis demonstrated that STMN1 expression was an independent prognostic factor for PDAC patients (P < 0.01). Herein, we provide the first evidence that up-regulated STMN1 may contribute to tumor progression and poor prognosis in PDAC patients and may serve as a novel prognostic marker.