Characterization of the Role of Caloric Restriction and Sir2.1 in the Heat Shock Response

The heat shock response (HSR) enables an organism to manage protein damaging stress through the activation of the transcription factor HSF1 and the induction of heat shock proteins (hsps). Understanding how the HSR is regulated is important as manipulating this response may be therapeutically beneficial for neurodegenerative disease and cancer. Previously, we have shown that the NAD+-dependent deactylase SIRT1 positively regulates the HSR, thus providing a direct link between the HSR and metabolism. We are further investigating this link using the nematode C. elegans. Caloric restriction (CR) induces the HSR and has been associated with longevity in C. elegans. We show here that heat shock and CR have a synergistic effect in inducing hsp genes. To determine if this effect depends on Sir2.1 (the C. elegans SIRT1 homolog) we will knockdown this gene using RNAi and expect to see a loss of synergy. In addition, we have analyzed the cytoprotective effect that induction of the HSR has on the ability of C. elegans to survive a lethal heat stress. We expect to see that both heat shock and CR promote increased survivability. This study will shed light on the effect of metabolism on the HSR and cytoprotection

X-ray irradiation induced Disabled-2 gene promoter de-methylation enhances radiosensitivity of non-small-cell lung carcinoma cells

Abstract Background Disabled-2 (Dab2) is known as a tumor suppressor as well as a Wnt pathway inhibitor. We previously reported that Dab2 was down-regulated due to gene promoter hypermethylation in lung cancer. Here, we aim to study if X-ray irradiation can induce de-methylation of the Dab2 gene and subsequently up-regulate its expression, and also to attempt to suppress the malignant biological behavior of and enhance the radiosensitivity in lung cancer cells with hypermethylation of the Dab2 gene. Methods Immunostaining was performed to investigate the relationship between Dab2 expression and lung cancer clinicopathological characteristics. Bisulfite sequencing PCR (BSP) was used to evaluate the methylation status of lung cancer cells with or without X-ray treatment. Real-time PCR and western Blot were performed to investigate the expression of Dab2, Wnt pathway factors, DNMTs and methyl CpG binding protein 2 (MeCP2). Colony Formation, matrigel invasion and xenograft experiment were performed to evaluate the malignant biological behavior of lung cancer cells with irradiation. Results The result of immunostaining of Dab2 in lung cancer tissues showed that decreased Dab2 expression was positively correlated with poor differentiation, lymph node metastasis, advanced TNM stage and poor prognosis. X-ray treatment significantly up-regulated Dab2 expression and inhibited Wnt factors in LK2 cells (with hypermethylation of the Dab2 gene promoter, P < 0.05), but not in SPC-A-1 cells (with hypomethylation of the Dab2 gene promoter); however, the effect could be reversed by Dab2 or Axin knockdown (P < 0.05). Decreased expression of DNMT1, DNMT3b and MeCP2 could be detected in both LK2 and SPC-A-1 cells compared to non-irradiated cells (P < 0.05). Both in vitro studies and in vivo xenograft tumor growth demonstrated that X-ray could significantly inhibit the proliferation and invasion of LK2 but not SPC-A-1 cells (P < 0.05). Conclusion In general, X-ray-induced up-regulation of Dab2 and inhibition of the Wnt pathway may be mediated by de-methylation of a hypermethylated Dab2 gene promoter. X-ray treatment significantly inhibits proliferation and invasion of lung cancer cells with hypermethylation of the Dab2 gene promoter, but is less effective in lung cancer cells with hypomethylation of the Dab2 gene promoter. These results indicate that the methylation status of the Dab2 gene promoter might be a potential predictor of the radiosensitivity of lung cancer cells

Tumor necrosis is an underappreciated histopathologic factor in the grading of chondrosarcoma

Abstract Background Cartilaginous neoplasms can be challenging to grade; there is a need to create an evidence-based rubric for grading. The goal of this study was to identify histopathologic features of chondrosarcoma that were associated with 5-year survival and to compare these to traditional patient, tumor and treatment variables. Methods This was a retrospective review of all patients undergoing surgical resection of a primary chondrosarcoma with at least 2 years of follow up. All specimens were independently reviewed by two pathologists and histopathologic features scored. Univariate and multivariate analyses were performed utilizing Kaplan Meier and proportional hazards methods to identify variables associated with 5-year disease specific survival (DSS) and disease free survival (DFS). Results We identified 51 patients with an average follow up of 49 months eligible for inclusion. 30% of tumors were low grade, 45% were intermediate grade, and 25% were high grade. In a univariate analysis considering histopathologic factors, higher tumor mitotic rate (HR 8.9, p < 0.001), tumor dedifferentiation (HR 7.3, p < 0.001), increased tumor cellularity (HR 5.8, p = 0.001), increased tumor atypia (HR 5.8, p = 0.001), LVI (HR 4.7, p = 0.04) and higher tumor necrosis (HR 3.7, p = 0.02) were all associated with worse 5-year DSS. In a multivariate analysis controlling for potentially confounding variables, higher tumor necrosis was significantly associated with disease specific survival survival (HR 3.58, p = 0.035); none of the factors were associated with DFS. Conclusions This study provides an evidence-based means for considering histopathologic markers and their association with prognosis in chondrosarcoma. Our findings suggest that necrosis and LVI warrant further study

The Utility of Chest Imaging for Surveillance of Atypical Lipomatous Tumors

BackgroundUnlike other soft tissue sarcomas, atypical lipomatous tumors (ALTs) are thought to have a low propensity for metastasis. Despite this, a standard of care for pulmonary metastasis (PM) surveillance has not been established. This study aimed to evaluate the utility of chest imaging for PM surveillance following ALT excision.MethodsThis was a multi-institution, retrospective review of all patients with primary ALTs of the extremities or superficial torso who underwent excision between 2006 and 2018. Minimum follow-up was two years. Long-term survival was evaluated using the Kaplan-Meier method.Results190 patients with ALT were included. Average age was 61.7 years and average follow-up was 58.6 months (24 to 180 months). MDM2 testing was positive in 88 patients (46.3%), and 102 (53.7%) did not receive MDM2 testing. 188 patients (98.9%) had marginal excision, and 127 (66.8%) had marginal or positive margins. Patients received an average of 0.9 CT scans and 1.3 chest radiographs over the surveillance period. 10-year metastasis-free survival was 100%, with no documented deaths from disease.ConclusionsThis study suggests that chest imaging does not have a significant role in PM surveillance following ALT excision, but advanced local imaging and chest surveillance may be considered in cases of local recurrence or concern for dedifferentiation