The nucleolar protein PinX1 has been proposed to be a putative tumor suppressor due to its binding to and inhibition of the catalytic activity of telomerase, an enzyme that is highly expressed in most human cancers in which it counteracts telomere shortening-induced senescence to confer cancer cell immortalization. However, the role of PinX1 in telomere regulation, as well as in cancer, is still poorly understood. In this study, we showed that the PinX1 protein is constitutively expressed in various human cells regardless of their telomerase activity and malignant status. Most interestingly, we found that silencing PinX1 expression by a potent short hairpin RNA construct led to a robust telomere length shortening and growth inhibition in telomerase-positive but not in telomerase-negative human cancer cells. We further showed that silencing PinX1 significantly reduced the endogenous association of telomerase with the Pot1-containing telomeric protein complex, and therefore, could account for the phenotypic telomere shortening in the affected telomerasepositive cancer cells. Our results thus reveal a novel positive role for PinX1 in telomerase/telomere regulations and suggest that the constitutive expression of PinX1 attributes to telomere maintenance by telomerase and tumorigenicity in cancer cells. [Cancer Res 2009;69(1):75-83]

Objective:We evaluated 3-D computed tomography angiography (3-D CTA) in the diagnosis of the nutcracker phenomenon, and its significance in postoperative follow up. Patients and Methods: Three-dimensional CTA was used to compare the anatomical relations of the left renal vein with the aorta and the superior mesenteric artery in patients with the nutcracker phenomenon and in a control group. Four patients with the nutcracker phenomenon received a surgical procedure of the transposition of the left renal vein. The 3-D CTA was used for all patients during postoperation follow-up testing. Results: The 3-D CTA showed a compression of the left renal vein between the aorta and the superior mesenteric artery (SMA) and the abnormal acute angle between them. The angles and distances between the SMA and the aorta were 39.3 ± 4.3° and 3.1 ± 0.2 mm in the patient groups and 90 ± 10° and 12 ± 1.8 mm in the control groups, respectively. Differences in angles and distances were statistically significant between the two groups (P < 0.05). Surgical transposition of the left renal vein was performed successfully. Postoperative 3-D CTA revealed the distance between the SMA and the aorta was nearly normal. Conclusion:The reconstruction imaging of the renal vein by means of 3-D CTA revealed that unusual hematuria was due to compression of the left renal vein; therefore it may be a useful alternative imaging technique instead of conventional examinations. The non-invasive 3-D CTA may be a useful tool in the diagnosis of the nutcracker phenomenon and follow-up testing.

We report on fabrication of a two-dimensional topological insulator-Bi(111) bilayer on Sb nanofilms via a sequential molecular beam epitaxy (MBE) growth technique. Our angle-resolved photoemission measurements demonstrate the evolution of the electronic band structure of the heterostructure as a function of the film thickness and reveal the existence of a two-dimensional spinful massless electron gas within the top Bi bilayer. Interestingly, Our first-principles calculation extrapolating the observed band structure shows that, by tuning down the thickness of the supporting Sb films into the quantum dimension regime, a pair of isolated topological edge states emerges in a partial energy gap at 0.32 eV above the Fermi level as a consequence of quantum confinement effect. Our results and methodology of fabricating nanoscale heterostructures establish the Bi bilayer/Sb heterostructure as a platform of great potential for both ultralow-energy-cost electronics and surface-based spintronics.

Supplementary Figure 1 from Silencing PinX1 Compromises Telomere Length Maintenance As Well As Tumorigenicity in Telomerase-Positive Human Cancer Cells

Supplementary Figure 2 from Silencing PinX1 Compromises Telomere Length Maintenance As Well As Tumorigenicity in Telomerase-Positive Human Cancer Cells