Phosphoinositide (PI) 3-kinases are required for the acute regulation of the cytoskeleton by growth factors. We have shown previously that in the MTLn3 rat adenocarcinoma cells line, the p85/p110␣ PI 3-kinase is required for epidermal growth factor (EGF)-stimulated lamellipod extension and formation of new actin barbed ends at the leading edge of the cell. We have now examined the role of the p85␣ regulatory subunit in greater detail. Microinjection of recombinant p85␣ into MTLn3 cells blocked both EGF-stimulated mitogenic signaling and lamellipod extension. In contrast, a truncated p85(1-333), which lacks the SH2 and iSH2 domains and does not bind p110, had no effect on EGF-stimulated mitogenesis but still blocked EGF-stimulated lamellipod extension. Additional deletional analysis showed that the SH3 domain was not required for inhibition of lamellipod extension, as a construct containing only the proline-rich and breakpoint cluster region (BCR) homology domains was sufficient for inhibition. Although the BCR domain of p85 binds Rac, the effects of the p85 constructs were not because of a general inhibition of Rac signaling, because sorbitol-induced JNK activation in MTLn3 cells was not inhibited. These data show that the proline-rich and BCR homology domains of p85 are involved in the coupling of p85/p110 PI 3-kinases to regulation of the actin cytoskeleton. These data provide evidence of a distinct cellular function for the N-terminal domains of p85.The regulation of cellular motility is important in a variety of physiological processes, ranging from wound healing to the metastatic behavior of transformed cells. We have used a metastatic breast cancer cell model, the MTLn3 cell, to study the role of phosphoinositide 3Ј-kinases in EGF 1 -stimulated motility (1). The acute regulation of the actin cytoskeleton by EGF requires the p85/p110␣ isoform of PI 3-kinase. MTLn3 breast cancer cells express similar levels of p85/p110␣ and p85/p110␤. However, EGF-stimulated lamellipod extension is blocked by microinjection of inhibitory antibodies to p110␣ but not p110␤ (2). Inhibition of p110␣ also blocks the production of new barbed ends at the leading edge of EGF-stimulated cells (2). Isoform-specific regulation of the cytoskeleton by class IA PI 3-kinases has also been described in macrophages and fibroblasts (3, 4). These findings suggest that different PI 3-kinase isoforms signal differently within the same cell.Although the mechanism by which PI 3-kinases affect the cytoskeleton are not clear, several potential pathways have recently emerged. Rho family GTPases are central in growth factor-mediated actin reorganization (5), and p85/p110 has been linked to Rac activation in platelet-derived growth factorstimulated cells (6). Furthermore, GTP exchange factors for Rac and CDC42 contain pleckstrin homology or (Fab1, YGL023, Vps27, EEAI) domains and are likely targets of 3-phosphoinositides (7-9). Potential effectors for Rac/CDC42-mediated cytoskeletal signaling include (a) the actin-severing protein cofilin, whose activi...

Background Ursolic acid (UA), a plant extract from traditional Chinese medicines as well as edible vegetables, exhibits a potent anticancer activity in various tumor cells. Annexin A1(AnxA1) is dysregulated and play a pivotal role in various tumor. However, the function of AnxA1 in breast cancer(BC) remains unclear. Methods Western blot, real-time quantitative polymerase chain reaction(qRT- PCR), transwell, wound healing and immunofluorescence were used to study the biological features of AnxA1 in breast cancer. The stemness of cancer cells was assessed by sphere formation assay. CCK-8 and flow cytometry assay were used to detect the effects of ursolic acid on the growth, proliferation and apoptosis of breast cancer cells in vitro. A nude mice xenograft model was employed in vivo. The potential mechanism by which Ursolic acid regulates the biological behaviors of breast cancer stem cells through AnxA1 via the wnt/β-catenin signaling pathway was tested by western blot, qRT- PCR and immunohistochemistry. Results AnxA1 was highly expressed in MDA-MB-231 cell line compared with MCF-7 cell line, Down-regulation of AnxA1 could reduce the mammosphere formation, inhibit EMT, decrease the ability of migration and invasion in MCF-7 and MDA-MB-231 cells. Ursolic acid can reduce the expression of AnxA1 and inhibit proliferation of breast cancer cells, stemness, EMT, migration and invasion, promote cell apoptosis of breast cancer cell. This studies suggest that the anticancer effects of AnxA1 knockdown and UA treatment may be realized by affecting the EMT process and the wnt/β-catenin signaling pathway. Conclusions This research suggest that AnxA1 knockdown enhanced the sensitivity of breast cancer cells to UA, the combination of UA treatment and AnxA1 knockdown possesses multiple anti-tumor activities against breast cancer, as it, in particular, inhibited the cancer stem cell and attenuated EMT. Therefore, it is emerging as a promising therapeutic strategy to inhibit breast cancer.

To elucidate respective effects of sodium and chloride ion on filament formation in Zymomonas mobilis232B culture induced by NaCl, the morphological changes of cell grown in medium containing 0.2 M (NH 4 ) 2 SO 4 , Na + (as Na 2 SO 4 ) and Cl -(as NH 4 Cl) were observed using a scanning electronic nicroscope (SEM). The occurrence of filament formation began as early as 4 h after exposuring to NaCl and Cl and the length was approximate 10 to 15 μm after exposuring for 20 h, which was 3 to 5 fold longer compared to normal cell, while Na + and (NH 4 ) 2 SO 4 treated cells kept normal morphology, indicating that filament formation in NaCl-inhibited Z. mobilis cultures is attributable to chloride ion. In the presence of 0.2 M chloride ion, increase in cell number stop almost immediately, whereas cells continued to elongate slowly, suggesting that chloride ion has a direct inhibitory effect on cell division.

Aggressive fibromatosis, also referred to as desmoid-type fibromatosis or desmoid tumor, is an uncommon locally invasive tumor with a high local recurrence rate. It rarely occurs in the breast and the etiology of aggressive breast fibromatosis is still unknown but may be related to previous mammary trauma or surgery. Preoperative diagnosis of aggressive breast fibromatosis is still a challenge for clinicians. The optimal treatment for the disease is still controversial, but wide surgical excision with negative margins is considered the standard option. We report a 28-year-old woman of aggressive breast fibromatosis accompanied with accessory breast mastitis in her ipsilateral axilla. The lesions imitated breast carcinoma with axillary lymph node metastasis due to their similar clinical and imaging manifestations. Her mammary mass finally underwent wide surgical excision, and negative margins were confirmed during the surgery. To our knowledge, this is an extremely rare case accompanied with axillary accessory breast mastitis and will contribute to the management of aggressive breast fibromatosis.