Spindle integrity is critical for efficient mitotic progression and accurate chromosome segregation. Deregulation of spindles often leads to structural and functional aberrations, ultimately promoting segregation errors and aneuploidy, a hallmark of most human cancers. Here we report the characterization of a previously identified human sarcoma antigen (gene located at 19p13.11), Hice1, an evolutionarily nonconserved 46-kDa coiled-coil protein. Hice1 shows distinct cytoplasmic localization and associates with interphase centrosomes and mitotic spindles, preferentially at the spindle pole vicinity. Depletion of Hice1 by RNA interference resulted in abnormal and unstable spindle configurations, mitotic delay at prometaphase and metaphase, and elevated aneuploidy. Conversely, loss of Hice1 had minimal effects on interphase centrosome duplication. We also found that both full-length Hice1 and Hice1-N1, which is composed of 149 amino acids of the N-terminal region, but not the mutant lacking the N-terminal region, exhibited activities of microtubule bundling and stabilization at a near-physiological concentration. Consistently, overexpression of Hice1 rendered microtubule bundles in cells resistant to nocodazole-or cold-treatment-induced depolymerization. These results demonstrate that Hice1 is a novel microtubule-associated protein important for maintaining spindle integrity and chromosomal stability, in part by virtue of its ability to bind, bundle, and stabilize microtubules.

Hec1 contributes to accurate chromosome segregation by mediating spindle assembly checkpoint (SAC) signals and microtubule binding to ensure proper spindle assembly. We found that serine 165 of Hec1 was phosphorylated preferentially at kinetochores of misaligned chromosomes. This phosphorylation is important for SAC maintenance via Mad1/Mad2 localization to kinetochores.

BackgroundNEK1, the first mammalian ortholog of the fungal protein kinase never-in-mitosis A (NIMA), is involved early in the DNA damage sensing/repair pathway. A defect in DNA repair in NEK1-deficient cells is suggested by persistence of DNA double strand breaks after low dose ionizing radiation (IR). NEK1-deficient cells also fail to activate the checkpoint kinases CHK1 and CHK2, and fail to arrest properly at G1/S or G2/M-phase checkpoints after DNA damage.ResultsWe show here that NEK1-deficient cells suffer major errors in mitotic chromosome segregation and cytokinesis, and become aneuploid. These NEK1-deficient cells transform, acquire the ability to grow in anchorage-independent conditions, and form tumors when injected into syngeneic mice. Genomic instability is also manifest in NEK1 +/- mice, which late in life develop lymphomas with a much higher incidence than wild type littermates.ConclusionNEK1 is required for the maintenance of genome stability by acting at multiple junctures, including control of chromosome stability.

The value of imaging living tissue is a significant benefit. Because keloids and hypertrophic scars result from altered collagen metabolism, the development of clinical multiphoton microscopy systems may allow examination of wound healing dynamics in vivo and potentially provides a means to monitor therapy without the need for biopsy or the risk of injury to tissue.

a b s t r a c tPurpose: To investigate the relationship between abdominal chemoradiation (CRT) for locally advanced cancers and bone mineral density (BMD) reduction in the vertebral spine. Materials and methods: Data from 272 patients who underwent abdominal radiation therapy from January 1997 to May 2015 were retrospectively reviewed. Forty-two patients received computed tomography (CT) scans of the abdomen prior to initiation and at least twice after radiation therapy. Bone attenuation (in Hounsfield unit) (HU) measurements were collected for each vertebral level from T7 to L5 using sagittal CT images. Radiation point dose was obtained at each mid-vertebral body from the radiation treatment plan. Percent change in bone attenuation (D%HU) between baseline and post-radiation therapy were computed for each vertebral body. The D%HU was compared against radiation dose using Pearson's linear correlation. Results: Abdominal radiotherapy caused significant reduction in vertebral BMD as measured by HU. Patients who received only chemotherapy did not show changes in their BMD in this study. The D%HU was significantly correlated with the radiation point dose to the vertebral body (R = À0.472, P < 0.001) within 4-8 months following RT. The same relationship persisted in subsequent follow up scans 9 months following RT (R = À0.578, P < 0.001). Based on the result of linear regression, 5 Gy, 15 Gy, 25 Gy, 35 Gy, and 45 Gy caused 21.7%, 31.1%, 40.5%, 49.9%, and 59.3% decrease in HU following RT, respectively. Our generalized linear model showed that pre-RT HU had a positive effect (b = 0.830) on determining post-RT HU, while number of months post RT (b = À0.213) and radiation point dose (b = À1.475) had a negative effect. A comparison of the predicted versus actual HU showed significant correlation (R = 0.883, P < 0.001) with the slope of the best linear fit = 0.81. Our model's predicted HU were within ±20 HU of the actual value in 53% of cases, 70% of the predictions were within ±30 HU, 81% were within ±40 HU, and 90% were within ±50 HU of the actual post-RT HU. Four of 42 patients were found to have vertebral body compression fractures in the field of radiation. Vertebral body insufficiency and compression fractures are most commonly caused by osteoporosis, an age-related and systemic skeletal disorder characterized by compromised bone strength and low bone mineral density [1]. Although, most fractures are asymptomatic, the degree of BMD loss, location of the fracture, and secondary osteoporosis from underlying medical condition including chemotherapy may make an asymptomatic, stable fracture more prone to progressive collapse causing pain, loss of mobility, and spinal cord compression [2]. The overall morbidity of vertebral body compression fractures is significant, and women diagnosed with compression fractures have a 15% higher mortality rate than matched controls [3].Irradiation of normal, non-malignant bone results in small vessel damage leading to microcirculatory occlusion, marrow hypocellularity from death of osteo...

Previous studies have stipulated Hec1 as a conserved kinetochore component critical for mitotic control in part by directly binding to kinetochore fibers of the mitotic spindle and by recruiting spindle assembly checkpoint proteins Mad1 and Mad2. Hec1 has also been reported to localize to centrosomes, but its function there has yet to be elucidated. Here, we show that Hec1 specifically colocalizes with Hice1, a previously characterized centrosomal microtubule-binding protein, at the spindle pole region during mitosis. In addition, the C-terminal region of Hec1 directly binds to the coiled-coil domain 1 of Hice1. Depletion of Hice1 by small interfering RNA (siRNA) reduced levels of Hec1 in the cell, preferentially at centrosomes and spindle pole vicinity. Reduction of de novo microtubule nucleation from mitotic centrosomes can be observed in cells treated with Hec1 or Hice1 siRNA. Consistently, neutralization of Hec1 or Hice1 by specific antibodies impaired microtubule aster formation from purified mitotic centrosomes in vitro. Last, disruption of the Hec1/Hice1 interaction by overexpressing Hice1DeltaCoil1, a mutant defective in Hec1 interaction, elicited abnormal spindle morphology often detected in Hec1 and Hice1 deficient cells. Together, the results suggest that Hec1, through cooperation with Hice1, contributes to centrosome-directed microtubule growth to facilitate establishing a proper mitotic spindle.

Purpose Radiation oncologists are frequently involved in providing palliative and supportive care (PSC) for patients with advanced cancers through delivery of palliative radiation. Whether they are confident in their ability to assess and initiate treatments for pain, nonpain, and psychosocial distress is unknown. The American Society for Radiation Oncology surveyed its practicing members in the United States on self-assessment of their primary PSC skills and access to continuing medical education on PSC. Methods We electronically surveyed 4093 practicing radiation oncologists in the United States. The survey consisted of 16-questions in 5 sections1: demographics,2 PSC training,3 domains of PSC,4 perceived barriers as a radiation oncologist to initiate advanced care planning, and5 discussion of prognosis. Results The survey was e-mailed to 4093 American Society for Radiation Oncology members, and 649 responses were received (response rate 16%). The majority (91%) of radiation oncologists surveyed believe PSC is an important competency for radiation oncologists. Most radiation oncologists reported that they are moderately confident in their ability to assess and manage pain and gastrointestinal symptoms, but less confident in their ability to manage anorexia, anxiety, and depression. Despite areas of decreased confidence, a large number (42%) of radiation oncologists do not receive any additional PSC education beyond their residency training. Lastly, a perceived fear of upsetting referring medical oncologists and lack of clinic time are concerns for radiation oncologists who may want to initiate goals of care/advance care planning discussions with patients and their families. Conclusion Radiation oncologists are more confident in their ability to assess and manage pain than in their ability to manage depression, anxiety, anorexia, and fatigue. There is a need for increasing continuing medical educational efforts in PSC for practicing radiation oncologists, and strengthening PSC training in residency programs.

Renal cell carcinoma (RCC) is a heterogeneous disease with resistance to systemic chemotherapy. Elevated expression of multiple drug resistance (MDR) has been suggested to be one of the mechanisms for this resistance. Here, we provide an alternative mechanism to explain RCC's resistance to chemotherapy-induced apoptosis. Never-in mitosis A-related protein kinase 1 (Nek1) plays an important role in DNA damage response and proper checkpoint activation. The association of Nek1 with the voltage-dependent anion channel (VDAC1) is a critical determinant of cell survival following DNA-damaging treatment. We report here that Nek1 is highly expressed in RCC tumor and cultured RCC cells compared to that of normal renal tubular epithelial cells (RTE). The association between Nek1 and VDAC1 is genotoxic dependent: prolonged Nek1/VDAC1 dissociation will lead to VDAC1 dephosphorylation and initiate apoptosis. Down-regulation of Nek1 expression in RCC cells enhanced their sensitivity to DNA-damaging treatment. Collectively, these results suggest that the increased Nek1 expression in RCC cells maintain persistent VDAC1 phosphorylation, closing its channel and preventing the onset of apoptosis under genotoxic insults. Based on these results, we believe that Nek1 can serve as a potential therapeutic target for drug development in the treatment of RCC.