Local Delivery of Adipose Stem Cells Promotes Allograft Survival in a Rat Hind-Limb Model of Vascularized Composite Allotransplantation.

BACKGROUND: Adipose stem cells (ASCs) are a promising cell-based immunotherapy because of their minimally invasive harvest, high yield, and immunomodulatory capacity. In this study, the authors investigated the effects of local versus systemic ASC delivery on vascularized composite allotransplant survival and alloimmune regulation. METHODS: Lewis rats received hind-limb transplants from Brown Norway rats and were administered donor-derived ASCs (passage 3 or 4, 1 × 10 6 cells/rat) locally in the allograft, or contralateral limb, or systemically at postoperative day 1. Recipients were treated intraperitoneally with rabbit anti-rat lymphocyte serum on postoperative days 1 and 4 and daily tacrolimus for 21 days. Limb allografts were monitored for clinical signs of rejection. Donor cell chimerism, immune cell differentiation, and cytokine expression in recipient lymphoid organs were measured by flow cytometric analysis. The immunomodulation function of ASCs was tested by mixed lymphocyte reaction assay and ASC stimulation studies. RESULTS: Local-ASC-treated recipients achieved significant prolonged allograft survival (85.7% survived >130 days; n = 6) compared with systemic-ASC and contralateral-ASC groups. Secondary donor skin allografts transplanted to the local-ASC long-term surviving recipients accepted permanently without additional immunosuppression. The increases in donor cell chimerism and regulatory T-cells were evident in blood and draining lymph nodes of the local-ASC group. Moreover, mixed lymphocyte reaction showed that ASCs inhibited donor-specific T-cell proliferation independent of direct ASC-T-cell contact. ASCs up-regulated antiinflammatory molecules in response to cytokine stimulation in vitro. CONCLUSION: Local delivery of ASCs promoted long-term survival and modulated alloimmune responses in a full major histocompatibility complex-mismatched vascularized composite allotransplantation model and was more effective than systemic administration. CLINICAL RELEVANCE STATEMENT: ASCs are a readily available and abundant source of therapeutic cells that could decrease the amount of systemic immunosuppression required to maintain limb and face allografts.

Evaluation of a Pharmacist-Linked Smoking Cessation Intervention for Adults Experiencing Homelessness.

Background: Interventions are needed to increase access to tobacco treatment for people experiencing homelessness. We developed a community pharmacist-linked cessation program for adults experiencing homelessness that included one-time, pharmacist-delivered counseling and furnishing nicotine replacement therapy (NRT) for 3 months. Methods: We conducted a single-arm, uncontrolled trial of the pharmacist-linked intervention among adults experiencing homelessness recruited from three homeless shelters in San Francisco, CA. We asked participants to complete questionnaires at baseline and during 12 weekly follow-up visits. We obtained information on cigarette consumption, use of NRT, and quit attempts at each visit, and reported cumulative proportions during the study interval. We used Poisson regression and logistic regression, respectively, to examine factors associated with weekly cigarette consumption and quit attempts. We conducted in-depth interviews with residents to understand barriers to and facilitators of engagement. Results: Among 51 participants, average daily cigarette consumption reduced 55% from 10 cigarettes per day at baseline to 4.5 cigarettes at 13 wk follow-up, and 56.3% had CO-verified abstinence. Use of medications in the past week was associated with a 29% reduction in weekly consumption (IRR 0.71, 95% CI 0.67-0.74), and increased the odds of a quit attempt (adjusted odds ratio (AOR), 2.37, 95% CI 1.13-4.99). While residents benefited from engaging in the pharmacist-linked program to increase quit attempts, they felt that to sustain abstinence, longitudinal tobacco treatment was needed. Conclusions: A pharmacist-linked smoking cessation program at transitional homeless shelters can reduce structural barriers to cessation care and reduce tobacco use among people experiencing homelessness.

Modification of bacterial microcompartments with target biomolecules via post-translational SpyTagging.

Bacterial microcompartments (BMCs) are proteinaceous organelle-like structures formed within bacteria, often encapsulating enzymes and cellular processes, in particular, allowing toxic intermediates to be shielded from the general cellular environment. Outside of their biological role they are of interest, through surface modification, as potential drug carriers and polyvalent antigen display scaffolds. Here we use a post-translational modification approach, using copper free click chemistry, to attach a SpyTag to a target protein molecule for attachment to a specific SpyCatcher modified BMC shell protein. We demonstrate that a post-translationally SpyTagged material can react with a SpyCatcher modified BMC and show its presence on the surface of BMCs, enabling future investigation of these structures as polyvalent antigen display scaffolds for vaccine development. This post-translational 'click' methodology overcomes the necessity to genetically encode the SpyTag, avoids any potential reduction in expression yield and expands the scope of SpyTag/SpyCatcher vaccine scaffolds to form peptide epitope vaccines and small molecule delivery agents.

Active Vitamin D3 (Calcitriol) Increases Adipose Graft Retention in a Xenograft Model.

BACKGROUND: Autologous fat grafting, although broadly indicated, is limited by unsatisfactory retention and often requires multiple procedures to achieve durable outcomes. Graft survival is strongly influenced by the magnitude and duration of post-engraftment ischemia. Calcitriol is a pleiotropic, safe nutrient with cell-specific influence on viability and metabolic flux. OBJECTIVES: Evaluate the efficacy of activated vitamin D3 (calcitriol) in improving grafting outcomes and examine its mechanisms. METHODS: Lipoaspirate was collected for ex vivo culture (7 unique donors), in vitro bioenergetic analysis (6 unique donors), and in vivo transplantation (5 unique donors). Ex vivo samples were incubated for up to 2 weeks before extraction of the stromal vascular fraction (SVF) for viability or flow cytometry. SVF was collected for Seahorse (Agilent; Santa Clara, CA) analysis of metabolic activity. Human endothelial cell lines were utilized for analyses of endothelial function. In vivo, samples were implanted into athymic mice with calcitriol treatment either (1) once locally or (2) 3 times weekly via intraperitoneal injection. Grafts were assessed photographically, volumetrically, and histologically at 1, 4, and 12 weeks. Hematoxylin and eosin (H&E), Sirius red, perilipin, HIF1α, and CD31 tests were performed. RESULTS: Calcitriol-treated lipoaspirate demonstrated dose-dependent increases in SVF viability and metabolic reserve during hypoxic stress. Calcitriol treatment enhanced endothelial mobility ex vivo and endothelial function in vitro. In vivo, calcitriol enhanced adipocyte viability, reduced fibrosis, and improved vascularity. Continuous calcitriol was sufficient to improve graft retention at 12 weeks (P < .05). CONCLUSIONS: Calcitriol increased fat graft retention in a xenograft model. Calcitriol has potential to be a simple, economical means of increasing fat graft retention and long-term outcomes.

Surgical Nipple Delay and its Expanded Indications for Nipple-sparing Mastectomy.

Necrosis of the nipple-areolar complex (NAC) or surrounding skin has been reported in 6%-30% of nipple-sparing mastectomy (NSM) patients, with higher rates associated with larger breasts, previous breast surgery, previous radiation, and active smoking. The nipple delay (ND) procedure is known to improve viability of the NAC in NSM patients with high-risk factors. Methods: A single-institution retrospective review was done of patients who underwent ND and NSM or NSM alone from 2012 to 2022. Patient demographics, risk factors, and outcomes were compared. Results: Forty-two breasts received ND-NSM and 302 breasts received NSM alone. The ND-NSM group had significantly more high-risk factors, including elevated BMI (26.3 versus 22.9; P < 0.001), elevated prior breast surgery (50% versus 25%; P < 0.001), and greater mastectomy specimen weight (646.6 versus 303.2 g; P < 0.001). ND-NSM was more likely to have undergone preparatory mammoplasty before NSM (27% versus 1%; P < 0.001). There was no delay in NSM treatment from decision to pursue NSM (P = 0.483) or difference in skin necrosis (P = 0.256), NAC necrosis (P = 0.510), hematoma (P = 0.094), seroma (P = 0.137), or infection (P = 0.437) between groups. ND-NSM and NSM patients differed in total NAC necrosis (0% versus 3%) and implant loss (0% vs 13%), but not significantly. Conclusions: We demonstrated no NAC necrosis and no significant delay of treatment in higher risk ND-NSM patients. ND may allow higher risk patients to undergo NSM with similar morbidity as lower risk patients.

Comparison of Soluble and Liposome Encapsulated, Sustained Release Latanoprost for Focal Adipose Reduction.

Background: To address the lack of non-cytotoxic, non-surgical options to treat undesirable focal adiposity of the face, we propose use of the anti-glaucoma medication and prostaglandin F2α analogue latanoprost, which has a well-described side effect of periorbital adipose shrinkage. Objective: To evaluate the safety and efficacy of soluble and liposomal latanoprost for focal fat reduction. Approach: To compare efficacy, single administrations of either the FDA-approved cytolytic drug deoxycholic acid (DOCA), latanoprost, or liposomal latanoprost were injected into ob/ob mouse inguinal fat pads. Study outcomes included mouse weight, inguinal fat pad volume, architecture, and cytotoxicity. Results: Both DOCA and soluble latanoprost significantly reduced inguinal fat pad volume whereas liposome encapsulation reduced inguinal fat pad volume insignificantly over the 14-day study period. Hematoxylin and eosin demonstrated effective reduction in adipocyte volume without histologic evidence of cytolysis or inflammation whereas DOCA caused dermal ulcerations, adipocyte lysis, and increased tissue inflammation. Conclusion: Latanoprost reduced fat volume without inducing cell lysis or inflammation.

Use of wound edge inversion (epibole) to generate recalcitrant and inflamed diabetic wounds.

Robust and predictive pre-clinical models of recalcitrant diabetic wounds are critical for advancing research efforts toward improving healing. Murine models have logistic and genetic benefits versus larger animals; however, native murine healing inadequately represents clinically recalcitrant wounds in humans. Furthermore, current humanization techniques employing devices, deleterious mutations or chemical agents each carry model-specific limitations. To better replicate human wounds in a mouse, we developed a novel wound-edge inversion (WEI) technique that mimics the architecture of epibole and mitigates contracture, epithelialization, and consequently wound closure. In this study, we evaluated the reliability and durability of the WEI model in wild-type and obese diabetic mice and compared to healing after (i) punch biopsy, (ii) mechanical/silicone stenting or (iii) exogenous oxidative stressors. In wild-type mice, WEI demonstrated favourable closure characteristics compared to both control and stented wounds, however, wounds progressed to closure by 4 weeks. In contrast, diabetic WEI wounds persisted for 6-10 weeks with reduced contracture and epithelialization. In both diabetic and wild-type mice, WEI sites demonstrated persistence of inflammatory populations, absence of epithelialization, and histologic presence of alpha-SMA positive granulation tissue when compared to controls. We conclude that the WEI technique is particularly valuable for modelling recalcitrant diabetic wounds with sustained inflammation and dysfunctional healing.

Quantifying the Pipeline of Ethnically Underrepresented in Medicine Physicians in Academic Plastic Surgery Leadership.

BACKGROUND: The lack of underrepresented in medicine (UIM) physicians in academic plastic surgery is emerging as a critical issue. Lack of diversity has a negative effect on patient care and on the culture of our health care system. This study reports the current status of ethnically UIM physicians in the plastic surgery pipeline, starting from the medical student level and progressing to national leadership positions. METHODS: The Electronic Residency Applications Service, National Resident Matching Program, Association of American Medical Colleges, and professional Web sites for journals and national societies were accessed for racial demographic information from 2008 to 2019. RESULTS: Over the past decade, there has been no change or a slight decrease in representation of Blacks among plastic surgery residency applicants, trainees, and academic faculty, at half or less than expected, compared with US Census data. The first point of drop-off occurs at the resident (3.8% of integrated and 5.6% of independent residents) to faculty level (<2.8%). Two percent of program directors and department heads/division chiefs are Black. The next point of drop-off occurs at the national level: there has never been a Black president of American Society of Plastic Surgeons or Plastic Surgery Foundation, and there are no Black editors-in-chiefs of major plastic surgery journals.Following LatinX American surgeons down the pipeline over the past decade, there has been no change or a decrease in representation among plastic surgery residency applicants, resident physicians, and academic faculty, at one-third or less than expected, compared with US Census data. The first point of drop-off occurs at the faculty (4.8%) to local leadership level (0% of program directors and department heads/division chiefs) where there is no representation of LatinX. Once this drop-off occurs, there is no recovery at the national leadership level. CONCLUSIONS: In order for our profession to reflect our nation's demographics, academic plastic surgery is in need of a paradigm shift now. Attrition of UIM physicians in plastic surgery begins at medical school graduation and persists through surgical training, faculty appointments, and attainment of leadership positions. Creative and innovative commitment to diversity and inclusion is necessary.

Local Recurrence Outcomes of Colorectal Cancer Oligometastases Treated With Stereotactic Ablative Radiotherapy.

PURPOSE: The aim of this study was to report local failure (LF) outcomes and associated predictors in patients with oligometastatic colorectal cancer (CRC) treated with stereotactic ablative radiotherapy (SABR). MATERIALS AND METHODS: We retrospectively reviewed patients with CRC metastases to the brain, liver, spine, or lung treated with SABR between 2001 and 2016. Time to LF was summarized using cumulative incidence of LF curves with death as a competing risk. RESULTS: The analysis included a total of 130 patients and 256 lesions. Of the metastases treated, 129 (50%) were brain, 50 (20%) liver, 49 (19%) spine, and 28 (11%) lung. Median gross tumor volume was 24 mL for liver metastases, 2 mL for brain metastases, 4 mL for spine metastases, and 1 mL for lung metastases. The overall 1, 2, and 3-year cumulative incidence of LF rates were 21.6% (16.5, 27.1), 28.2% (22.3, 34.4), and 31.5% (25.2, 38.0), respectively. LF was highest among the liver metastases (1 y: 26.0%, 2 y: 38.5%), followed by spine (1 y: 25.1%, 2 y: 31.1%), brain (1 y: 20%, 2 y: 25.2%), and lung (1 y: 13.7%, 2 y: insufficient data). Metastases from right-sided primary CRC were significantly more likely to have LF (P=0.0146, HR=2.23). Biologically effective dose>70 Gy, defined using a standard linear quadratic model using α/ß ratio of 10 on the individual lesion level, and pre-SABR chemotherapy were also significant predictors of LF (P= 0.0009 and 0.018, respectively). CONCLUSIONS: CRC metastases treated with SABR had significantly higher rates of LF if they originated from right-sided primary CRC, compared with left-sided. Liver metastases had the highest rates of LF compared with other metastatic sites. Thus, CRC liver metastases and metastases from right-sided CRC may benefit from more aggressive radiotherapy.

Access and communication for deaf individuals in Australian primary care.

BACKGROUND AND AIMS: The Australian Deaf Community face barriers that impede their access to, and communication within, primary health care settings. This study aimed to identify barriers and facilitators to access and communication for deaf individuals and Auslan interpreters in Australian general practice settings. METHODS: Semi-structured interviews were conducted with eight Auslan interpreters and four deaf participants recruited from interpreter organisations and social media. Transcripts of interviews were coded inductively and deductively based on a model of access to health care. RESULTS: Patient, provider and contextual factors were reported. Patient barriers included English and Auslan fluency levels within the Australian Deaf Community. GP clinics varied in the degree of accommodation to the needs of deaf people. There were barriers related to the communication methods used by health care providers and their use of interpreters. Visual aids and flexibility in terms of the GP clinics' appointment systems facilitated access. Contextual barriers included the shortage of Auslan interpreters and the complexity of the National Disability Insurance Scheme. CONCLUSION: The main barriers identified concerned the availability of interpreters, accommodation by health providers, cultural sensitivity and the adequacy of communication methods. Research is needed to explore the limitations of the National Disability Insurance Scheme and interventions to improve GPs' skills in communicating with Deaf individuals. PATIENT OR PUBLIC CONTRIBUTION: A researcher with a hearing impairment and experience in working with people with hearing impairments was consulted on study design and interview questions. Recruitment was assisted by Auslan interpreter agencies and a Deaf Community Facebook group.

Cross-sectional study of prevalence and risk factors, and a cost-effectiveness evaluation of screening and preventive treatment strategies for latent tuberculosis among migrants in Singapore.

OBJECTIVES: WHO recommends that low burden countries consider systematic screening and treatment of latent tuberculosis infection (LTBI) in migrants from high incidence countries. We aimed to determine LTBI prevalence and risk factors and evaluate cost-effectiveness of screening and treating LTBI in migrants to Singapore from a government payer perspective. DESIGN: Cross-sectional study and cost-effectiveness analysis. SETTING: Migrants in Singapore. PARTICIPANTS: 3618 migrants who were between 20 and 50 years old, have not worked in Singapore previously and stayed in Singapore for less than a year were recruited. PRIMARY AND SECONDARY OUTCOME MEASURES: Costs, quality-adjusted life-years (QALYs), threshold length of stay, incremental cost-effectiveness ratios (ICERs), cost per active TB case averted. RESULTS: Of 3584 migrants surveyed, 20.4% had positive interferon-gamma release assay (IGRA) results, with the highest positivity in Filipinos (33.2%). Higher LTBI prevalence was significantly associated with age, marital status and past TB exposure. The cost-effectiveness model projected an ICER of S$57 116 per QALY and S$12 422 per active TB case averted for screening and treating LTBI with 3 months once weekly isoniazid and rifapentine combination regimen treatment compared with no screening over a 50-year time horizon. ICER was most sensitive to the cohort's length of stay in Singapore, yearly disease progression rates from LTBI to active TB, followed by the cost of IGRA testing. CONCLUSIONS: For LTBI screening and treatment of migrants to be cost-effective, migrants from high burden countries would have to stay in Singapore for ~50 years. Risk-stratified approaches based on projected length of stay and country of origin and/or age group can be considered.

Phospholipid transfer protein (PLTP) deficiency attenuates high fat diet induced obesity and insulin resistance.

Increased phospholipid transfer protein (PLTP) activity has been found to be associated with obesity, and metabolic syndrome in humans. However, whether or not PLTP has a direct effect on insulin sensitivity and obesity is largely unknown. Here we analyzed the effect by using PLTP knockout (PLTP-/-) mouse model. Although, PLTP-/- mice have normal body-weight-gain under chow diet, these mice were protected from high-fat-diet-induced obesity and insulin resistance, compared with wild type mice. In order to understand the mechanism, we evaluated insulin receptor and Akt activation and found that PLTP deficiency significantly enhanced phosphorylated insulin receptor and Akt levels in high-fat-diet fed mouse livers, adipose tissues, and muscles after insulin stimulation, while total Akt and insulin receptor levels were unchanged. Moreover, we found that the PLTP deficiency induced significantly more GLUT4 protein in the plasma membranes of adipocytes and muscle cells after insulin stimulation. Finally, we found that PLTP-deficient hepatocytes had less sphingomyelins and free cholesterols in the lipid rafts and plasma membranes than that of controls and this may provide a molecular basis for PLTP deficiency-mediated increase in insulin sensitivity. We have concluded that PLTP deficiency leads to an improvement in tissue and whole-body insulin sensitivity through modulating lipid levels in the plasma membrane, especially in the lipid rafts.

Convolutional neural networks automate detection for tracking of submicron-scale particles in 2D and 3D.

Particle tracking is a powerful biophysical tool that requires conversion of large video files into position time series, i.e., traces of the species of interest for data analysis. Current tracking methods, based on a limited set of input parameters to identify bright objects, are ill-equipped to handle the spectrum of spatiotemporal heterogeneity and poor signal-to-noise ratios typically presented by submicron species in complex biological environments. Extensive user involvement is frequently necessary to optimize and execute tracking methods, which is not only inefficient but introduces user bias. To develop a fully automated tracking method, we developed a convolutional neural network for particle localization from image data, comprising over 6,000 parameters, and used machine learning techniques to train the network on a diverse portfolio of video conditions. The neural network tracker provides unprecedented automation and accuracy, with exceptionally low false positive and false negative rates on both 2D and 3D simulated videos and 2D experimental videos of difficult-to-track species.

ZMapp Reinforces the Airway Mucosal Barrier Against Ebola Virus.

Filoviruses, including Ebola, have the potential to be transmitted via virus-laden droplets deposited onto mucus membranes. Protecting against such emerging pathogens will require understanding how they may transmit at mucosal surfaces and developing strategies to reinforce the airway mucus barrier. Here, we prepared Ebola pseudovirus (with Zaire strain glycoproteins) and used high-resolution multiple-particle tracking to track the motions of hundreds of individual pseudoviruses in fresh and undiluted human airway mucus isolated from extubated endotracheal tubes. We found that Ebola pseudovirus readily penetrates human airway mucus. Addition of ZMapp, a cocktail of Ebola-binding immunoglobulin G antibodies, effectively reduced mobility of Ebola pseudovirus in the same mucus secretions. Topical delivery of ZMapp to the mouse airways also facilitated rapid elimination of Ebola pseudovirus. Our work demonstrates that antibodies can immobilize virions in airway mucus and reduce access to the airway epithelium, highlighting topical delivery of pathogen-specific antibodies to the lungs as a potential prophylactic or therapeutic approach against emerging viruses or biowarfare agents.

Stereolithography-Based 3D Printed "Pillar Plates" that Minimizes Fluid Transfers During Enzyme Linked Immunosorbent Assays.

Enzyme linked immunosorbent assay (ELISA) is one of the most popular and indispensable tools in molecular biology. Despite numerous advances in ELISA methods that markedly improve the sensitivity and throughput of detection, a hallmark of all ELISA continues to be repeated pipetting of fluids that is not only cumbersome but can easily introduce errors or contaminations. Robotics, despite obvious advantages, remains expensive. Here, we designed and produced cheap "pillar plates" using stereolithography-based 3D printing that can be readily inserted into conventional 96- and 384- well plates and serve as the substrate for ELISA. We demonstrate that ELISA using these "pillar plates" affords comparable specificity and sensitivity of detection of serum antibodies to traditional sandwich ELISA, while markedly reducing the time and efforts associated with fluid transfer. These results underscore "pillar plates" as an attractive platform for rapid yet robotics-free ELISA.

Continuous ambulatory adductor canal catheters for patients undergoing knee arthroplasty surgery.

STUDY OBJECTIVE: To determine after knee arthroplasty surgery the feasibility of discharging patients home on postoperative day 1 with continuous adductor canal blocks. DESIGN: Retrospective case series. SETTING: Outpatient setting after hospital discharge. PATIENTS: Patients undergoing knee arthroplasty surgery from October 2013 to August 2014. INTERVENTIONS: All patients received continuous adductor canal catheters for postoperative analgesia and were discharged to home on postoperative day 1. Continuous catheters were intended to remain intact in the ambulatory setting through postoperative day 3. MEASUREMENTS: Data obtained included demographic information, duration of hospital stay, resting and active pain scores, opioid utilization, opioid-induced adverse effects, complications relating to the perineural catheter, and hospital readmissions. MAIN RESULTS: Sixty-nine of 582 patients (11.9%) were discharged to home on postoperative day 1. The median numerical pain score after discharge with a continuous adductor canal block was ≤2 at rest and ≤4 with activity. After block discontinuation on postoperative day 4, median pain scores were the same. No patients reported any unintentional catheter dislodgements, falls, or dysesthesias. There were no readmissions of any patient in this cohort within 90 days of surgery. CONCLUSIONS: Ambulatory adductor canal catheters are a feasible analgesic modality after knee arthroplasty surgery as pain scores remained low and adverse events were minimal.

Acupoint stimulation, massage therapy and expressive writing for breast cancer: A systematic review and meta-analysis of randomized controlled trials.

UNLABELLED: Researches have accumulated using non-pharmacologic interventions including acupoint stimulation, massage therapy and expressive writing to manage breast cancer-related symptoms. Results from randomized controlled trials (RCTs) can get contradictory. OBJECTIVE: A systematic review and meta-analysis were conducted to determine the effects on the quality of life, negative emotions and disease-related symptoms among women with breast cancer. METHODS: Two independent researchers performed a structured search using data sources including MEDLINE, CINAHL, Cochrane Central Register of Controlled Trials, EMBASE, PubMed and PsychINFO from the beginning of time until the first week of January 2015. A total of 23 acupoint stimulation, massage therapy and expressive writing RCTs were included in the review. RESULTS: The study showed that no single intervention could be put under the spotlight exhibiting an overall effective result on all measured outcomes; however, looking into each one in detail shows different results in specific outcomes. Among the three interventions, acupoint stimulation has a treatment effect for general pain (MD=-1.46, 95% CI=-2.38 to -0.53) and fatigue (MD=-2.22, 95% CI=-3.68 to -0.77), massage therapy has a treatment effect for anxiety (MD=-0.50, 95% CI=-0.77 to -0.24), and expressive writing has a treatment effect for quality of life (MD=7.18, 95% CI=0.38 to 13.98). The measurement other outcomes showed either ineffective or equivocal results. CONCLUSION: Non-pharmacologic interventions including acupoint stimulation, massage therapy and expressive writing have an effect on a middle-age woman with breast cancer. However, because of limitations, the seemingly promising results should be interpreted with caution.

RAD51B Activity and Cell Cycle Regulation in Response to DNA Damage in Breast Cancer Cell Lines.

Common genetic variants mapping to two distinct regions of RAD51B, a paralog of RAD51, have been associated with breast cancer risk in genome-wide association studies (GWAS). RAD51B is a plausible candidate gene because of its established role in the homologous recombination (HR) process. How germline genetic variation in RAD51B confers susceptibility to breast cancer is not well understood. Here, we investigate the molecular function of RAD51B in breast cancer cell lines by knocking down RAD51B expression by small interfering RNA and treating cells with DNA-damaging agents, namely cisplatin, hydroxyurea, or methyl-methanesulfonate. Our results show that RAD51B-depleted breast cancer cells have increased sensitivity to DNA damage, reduced efficiency of HR, and altered cell cycle checkpoint responses. The influence of RAD51B on the cell cycle checkpoint is independent of its role in HR and further studies are required to determine whether these functions can explain the RAD51B breast cancer susceptibility alleles.

Targeting DNA-PKcs and telomerase in brain tumour cells.

BACKGROUND: Patients suffering from brain tumours such as glioblastoma and medulloblastoma have poor prognosis with a median survival of less than a year. Identifying alternative molecular targets would enable us to develop different therapeutic strategies for better management of these tumours. METHODS: Glioblastoma (MO59K and KNS60) and medulloblastoma cells (ONS76) were used in this study. Telomerase inhibitory effects of MST-312, a chemically modified-derivative of epigallocatechin gallate, in the cells were assessed using telomere repeat amplification protocol. Gene expression analysis following MST-312 treatment was done by microarray. Telomere length was measured by telomere restriction fragments analysis. Effects of MST-312 on DNA integrity were evaluated by single cell gel electrophoresis, immunofluorescence assay and cytogenetic analysis. Phosphorylation status of DNA-PKcs was measured with immunoblotting and effects on cell proliferation were monitored with cell titre glow and trypan blue exclusion following dual inhibition. RESULTS: MST-312 showed strong binding affinity to DNA and displayed reversible telomerase inhibitory effects in brain tumour cells. In addition to the disruption of telomere length maintenance, MST-312 treatment decreased brain tumour cell viability, induced cell cycle arrest and double strand breaks (DSBs). DNA-PKcs activation was observed in telomerase-inhibited cells presumably as a response to DNA damage. Impaired DNA-PKcs in MO59J cells or in MO59K cells treated with DNA-PKcs inhibitor, NU7026, caused a delay in the repair of DSBs. In contrast, MST-312 did not induce DSBs in telomerase negative osteosarcoma cells (U2OS). Combined inhibition of DNA-PKcs and telomerase resulted in an increase in telomere signal-free chromosomal ends in brain tumour cells as well. Interestingly, continual exposure of brain tumour cells to telomerase inhibitor led to population of cells, which displayed resistance to telomerase inhibition-mediated cell arrest. DNA-PKcs ablation in these cells, however, confers higher cell sensitivity to telomerase inhibition, inducing cell death. CONCLUSIONS: Efficient telomerase inhibition was achieved with acute exposure to MST-312 and this resulted in subtle but significant increase in DSBs. Activation of DNA-PKcs might indicate the requirement of NHEJ pathway in the repair telomerase inhibitor induced DNA damage. Therefore, our results suggest a potential strategy in combating brain tumour cells with dual inhibition of telomerase and NHEJ pathway.