Narciclasine, a potential allelochemical, affects subcellular trafficking of auxin transporter proteins and actin cytoskeleton dynamics in Arabidopsis roots
PLANTA
Authors: Hu, Yanfeng; Na, Xiaofan; Li, Jiaolong; Yang, Lijing; You, Jia; Liang, Xiaolei; Wang, Jianfeng; Peng, Liang; Bi, Yurong
Abstract
The present study documented the action of a potential allelochemical, narciclasine, on auxin transport in Arabidopsis by mainly affecting subcellular trafficking of PIN and AUX1 proteins and through interfering actin cytoskeletal organization. Narciclasine (NCS), an Amaryllidaceae alkaloid isolated from Narcissus tazetta bulbs, has potential allelopathic activity and affects auxin transport. However, little is known about the cellular mechanism of this inhibitory effect of NCS on auxin transport. The present study characterizes the effects of NCS at the cellular level using transgenic Arabidopsis plants harboring the promoters of PIN, in combination with PIN-GFP proteins or AUX1-YFP fusions. NCS treatment caused significant reduction in the abundance of PIN and AUX1 proteins at the plasma membrane (PM). Analysis of the subcellular distribution of PIN and AUX1 proteins in roots revealed that NCS induced the intracellular accumulation of auxin transporters, including PIN2, PIN3, PIN4, PIN7 and AUX1. However, other PM proteins, such as PIP2, BRI1, and low temperature inducible protein 6b (LTI6b), were insensitive to NCS treatment. NCS-induced PIN2 compartments were further defined using endocytic tracer FM 4-64 labeled early endosomes and suggested that this compound affects the endocytosis trafficking of PIN proteins. Furthermore, pharmacological analysis indicated that the brefeldin A (BFA)-insensitive pathway is employed in the cellular effects of NCS on PIN2 trafficking. Although NCS did not alter actin dynamics in vitro, it resulted in the depolymerization of the actin cytoskeleton in vivo. This disruption of actin filaments by NCS subsequently influences the actin-based vesicle motility. Hence, the elucidation of the specific role of NCS is useful for further understanding the mechanisms of allelopathy at the phytohormone levels.
Aberrant Expression of p63 in Adenocarcinoma of the Prostate A Radical Prostatectomy Study
AMERICAN JOURNAL OF SURGICAL PATHOLOGY
Authors: Giannico, Giovanna A.; Ross, Hillary M.; Lotan, Tamara; Epstein, Jonathan I.
Abstract
Prostatic adenocarcinoma with aberrant diffuse expression of p63 (p63-PCa) is a recently described variant of prostatic adenocarcinoma. The aim of this study was to investigate the clinical and pathologic features of p63-PCa at radical prostatectomy (RP). We reviewed 21 cases of p63-PCa diagnosed on needle biopsy at subsequent RP. Immunohistochemical analysis for PIN4 and Ki-67 was performed in all RP cases. p63-PCa showed a distinctive morphology consisting of atrophic, poorly formed glands, with multilayered and often spindled nuclei. Gleason grading was 3 + 3 = 6 in 28.5%, 3+ 5 = 8 in 38%, 3 vertical bar 4 = 7 in 14.3%, and 4 vertical bar 3 = 7, 5 vertical bar 3 = 8, and 5 vertical bar 4 = 9 in 9.5%. Usual-type acinar carcinoma coexisted in 85.7% with only p63-PCa present in the remaining cases. The usual-type carcinoma was Gleason grade 3 + 2 = 5 in 4.7%, 3+ 3= 6 in 57%, 3+ 4 = 7 in 19%, and 4+ 3= 7 in 4.3%. Overall, p63-PCa represented 65% of the total cancer volume (median 80%). The tumor was organ-confined in 16 cases (76.2%). In the remaining 5 cases, 2 had p63-PCa extending to the margin in areas of intraprostatic incisions, 2 had usual-type acinar adenocarcinoma extending to the margin and extraprostatic tissue, respectively, and 1 had p63-PCa with an unusual cribriform morphology involving the bladder neck. Ki-67 was low, < 5% in all cases of p63-PCa, with similar expression in the coexisting acinar-type carcinoma. In summary, it is recommended that these tumors not be assigned a Gleason score and their favorable findings at RP be noted.