Probes for INS

Abstract: Objective: To investigate the potential involvement of secreted protein acidic and rich in cysteine (SPARC) in the progression of the breast tumor and to determine its association with outcome variables and matrix metalloproteinases (MMPs) expression in patients with breast carcinoma (BC). Methods: SPARC expression was examined in 8 pairs of BC tissues and surrounding normal tissues at mRNA and protein levels by qRT-PCR, RNAscope in situ hybridization (ISH), Western blotting, and immunohistochemistry techniques. Immunohistochemical staining of SPARC was done in 26 normal breasts, 76 ductal carcinoma in situ (DCIS), and 198 BC samples. In addition, immunohistochemical staining was performed for MMP-2 and MMP-9 in BC. Results: SPARC expression at mRNA and protein levels was significantly increased in BC tissues compared to the surrounding normal tissues (P < 0.05 and P < 0.01, respectively). RNAscope ISH and immunohistochemistry of SPARC confirmed an increase in SPARC expression in BC tissues compared with the normal tissues. Epithelial SPARC expression increased continuously from normal breast through DCIS to BC (P < 0.001). In patients with BC, high epithelial SPARC expression was associated with worse disease-free survival and overall survival (P = 0.002 and P = 0.048, respectively) and independently predicted worse disease-free survival (P = 0.002). Epithelial SPARC expression was significantly correlated with MMP-2 expression (P < 0.05). Conclusion: Up-regulation of SPARC contributes to breast tumor progression. SPARC expression may be a useful biomarker for the prognostic prediction in patients with BC. SPARC can control extracellular matrix degradation through up-regulation of MMP-2.

Secreted protein acidic and rich in cysteine (SPARC) plays an essential role in tumor invasion and metastasis. The present work was undertaken to detect expression of SPARC mRNA in phyllodes tumors (PTs) and its association with SPARC protein expression. This study also evaluated expression of SPARC mRNA and its correlation between grade and clinical behavior of PTs. In addition, we assessed in PTs the association of expression of SPARC with that of matrix metalloproteinase (MMP)-2 and of MMP-9. SPARC mRNA expression was determined by RNAscope in situ hybridization (ISH) in 50 benign, 22 borderline, and 10 malignant PTs using a tissue microarray. Furthermore, we applied immunohistochemistry (IHC) to examine expression of SPARC, MMP-2, and MMP-9. SPARC mRNA appeared to be concentrated mainly in the stromal compartment of PTs. IHC staining patterns of SPARC protein showed concordance with SPARC mRNA ISH results. Stromal SPARC expression increased continuously as PTs progress from benign through borderline to malignant PTs, both at mRNA (using ISH) (P = 0.044) and protein level (using IHC) (P = 0.000). The recurrence percentage was higher in the stromal SPARC mRNA or protein-positive group than in the SPARC-negative group but this difference was not statistically significant. Stromal SPARC mRNA and protein expression was associated with PT grade and correlated with MMP-2 expression. These results indicate that SPARC-mediated degradation of the extracellular matrix, and its possible association with MMPs, might contribute to progression of PTs.

How stem cells maintain their identity and potency as tissues change during growth is not well understood. In mammalian hair, it is unclear how hair follicle stem cells can enter an extended period of quiescence during the resting phase but retain stem cell potential and be subsequently activated for growth. Here, we use lineage tracing and gene expression mapping to show that the Wnt target gene Axin2 is constantly expressed throughout the hair cycle quiescent phase in outer bulge stem cells that produce their own Wnt signals. Ablating Wnt signaling in the bulge cells causes them to lose their stem cell potency to contribute to hair growth and undergo premature differentiation instead. Bulge cells express secreted Wnt inhibitors, including Dickkopf (Dkk) and secreted frizzled-related protein 1 (Sfrp1). However, the Dickkopf 3 (Dkk3) protein becomes localized to the Wnt-inactive inner bulge that contains differentiated cells. We find that Axin2 expression remains confined to the outer bulge, whereas Dkk3 continues to be localized to the inner bulge during the hair cycle growth phase. Our data suggest that autocrine Wnt signaling in the outer bulge maintains stem cell potency throughout hair cycle quiescence and growth, whereas paracrine Wnt inhibition of inner bulge cells reinforces differentiation.