Targeting LxCxE cleft pocket of retinoblastoma protein in M2 macrophages inhibits ovarian cancer progression.

Ovarian cancer remains a major health threat with limited treatment options available. It is characterized by immunosuppressive tumor microenvironment (TME) maintained by tumor- associated macrophages (TAMs) hindering anti-tumor responses and immunotherapy efficacy. Here we show that targeting retinoblastoma protein (Rb) by disruption of its LxCxE cleft pocket, causes cell death in TAMs by induction of ER stress, p53 and mitochondria-related cell death pathways. A reduction of pro-tumor Rb high M2-type macrophages from TME in vivo enhanced T cell infiltration and inhibited cancer progression. We demonstrate an increased Rb expression in TAMs in women with ovarian cancer is associated with poorer prognosis. Ex vivo, we show analogous cell death induction by therapeutic Rb targeting in TAMs in post-surgery ascites from ovarian cancer patients. Overall, our data elucidates therapeutic targeting of the Rb LxCxE cleft pocket as a novel promising approach for ovarian cancer treatment through depletion of TAMs and re-shaping TME immune landscape. Statement of significance: Currently, targeting immunosuppressive myeloid cells in ovarian cancer microenvironment is the first priority need to enable successful immunotherapy, but no effective solutions are clinically available. We show that targeting LxCxE cleft pocket of Retinoblastoma protein unexpectedly induces preferential cell death in M2 tumor-associated macrophages. Depletion of immunosuppressive M2 tumor-associated macrophages reshapes tumor microenvironment, enhances anti-tumor T cell responses, and inhibits ovarian cancer. Thus, we identify a novel paradoxical function of Retinoblastoma protein in regulating macrophage viability as well as a promising target to enhance immunotherapy efficacy in ovarian cancer.

Aggregation of alpha-synuclein disrupts mitochondrial metabolism and induce mitophagy via cardiolipin externalization.

Accumulation of α-synuclein aggregates in the substantia nigra pars compacta is central in the pathophysiology of Parkinson's disease, leading to the degeneration of dopaminergic neurons and the manifestation of motor symptoms. Although several PD models mimic the pathological accumulation of α-synuclein after overexpression, they do not allow for controlling and monitoring its aggregation. We recently generated a new optogenetic tool by which we can spatiotemporally control the aggregation of α-synuclein using a light-induced protein aggregation system. Using this innovative tool, we aimed to characterize the impact of α-synuclein clustering on mitochondria, whose activity is crucial to maintain neuronal survival. We observed that aggregates of α-synuclein transiently and dynamically interact with mitochondria, leading to mitochondrial depolarization, lower ATP production, mitochondrial fragmentation and degradation via cardiolipin externalization-dependent mitophagy. Aggregation of α-synuclein also leads to lower mitochondrial content in human dopaminergic neurons and in mouse midbrain. Interestingly, overexpression of α-synuclein alone did not induce mitochondrial degradation. This work is among the first to clearly discriminate between the impact of α-synuclein overexpression and aggregation on mitochondria. This study thus represents a new framework to characterize the role of mitochondria in PD.

Burn Injury Complications Impacting Rehabilitation.

Successful post-burn rehabilitation requires an understanding of a wide range of complications to maximize functional recovery. This article reviews a range of potential challenges including burn scar contracture, amputation, peripheral nerve injury, heterotopic ossification, dysphagia, altered skin physiology, pain, and pruritis. The overall focus is to serve as a guide for post-injury therapy and rehabilitation spanning the phases of care and considering evidence-based approaches, prevention, and treatment with an ultimate goal of aiding in the functional recovery and long-term quality of life for burn survivors.

Novel Design and Implementation of an Integrated Burn Rehabilitation Clinical Fellowship.

ABSTRACT: Postgraduate medical burn rehabilitation training has been limited, with very few academic physiatrists specializing in burn rehabilitation. As a result, there are no existing models for postgraduate burn rehabilitation education. A 12-mo comprehensive clinical fellowship in burn rehabilitation was offered through a tertiary burn center with formal university accreditation. In this article, the clinical, educational, and skill-based goals developed and implemented for this novel fellowship was outlined to serve as a blueprint for future fellowships in burn rehabilitation, as well as reflections on the experience.

Assessment of pharmacy technician job satisfaction and duties in ambulatory care pharmacy settings: A mixed-methods analysis.

PURPOSE: Expansion of pharmacy services into ambulatory care has prompted the integration of pharmacy technicians into this setting. Many models exist for technician practice in ambulatory care, and job satisfaction in these settings needs evaluation. This study assessed the job satisfaction of ambulatory care pharmacy technicians, obtained a deeper understanding of their varied roles, and examined commitment to the pharmacy technician career and their employing organization. METHODS: This study used a mixed-methods sequential explanatory design of quantitative followed by qualitative data analysis. The phases included a validated questionnaire on job satisfaction and semistructured interviews using a modified guide and findings from the quantitative data. Descriptive statistics and constant comparative analysis were used to analyze quantitative and qualitative data, and data were integrated in the discussion. RESULTS: The questionnaire was sent to 125 potential participants at 11 organizations in 8 unique states. Seventy-four technicians participated in the quantitative phase. Seventeen of these were interviewed in the qualitative phase. Interviewees represented 7 different institutions in 6 states in the Southeast, Midwest, and Western regions of the US. Both phases indicated that respondents felt a strong commitment to their organization, with 60% of respondents indicating this on the questionnaire. Reasons for this commitment were further elucidated in the qualitative phase, which indicated high satisfaction with technician autonomy, work schedules, and ability to provide important services to patients. It was also found in both phases that technician duties varied greatly among organizations, although most technicians were involved in facilitating medication access. CONCLUSION: Ambulatory care pharmacy technicians are highly satisfied with their positions and careers. Although technician roles vary within ambulatory care settings, the majority involve facilitating medication access in various ways. As these positions become more prevalent in pharmacy practice, it will be important to continue to capitalize on satisfiers and mitigate dissatisfiers to advance the profession and ultimately provide optimal patient care.

Anterior Elbow Heterotopic Ossification in Patient With Pemphigus Vulgaris: An Unheard Complication of a Rare Condition.

Pemphigus vulgaris is a potentially fatal disease within the epidermis with rare noncutaneous manifestations. Heterotopic ossification has not been previously described as one of the inherent complications of this skin pathology. A 44-year-old man presented with severe pemphigus vulgaris involving 80 to 90% of his body surface area. He had an extended time to wound closure of 5 months, as well as two additional months bed bound due to related infectious and respiratory complications. He progressively developed a worsening range of motion at his bilateral elbows. X-ray demonstrated bilateral anterior elbow heterotopic ossification. Passive and active range of motion exercises were initiated early in the course of his treatment and only yielded a small positive effect. Thus, screening for heterotopic ossification may be warranted when a significant joint range of motion is lost in cases of autoimmune cutaneous disease, and even more in the presence of severe open wounds with delayed wound closure.

The transcription factor hepatocyte nuclear factor 4A acts in the intestine to promote white adipose tissue energy storage.

The transcription factor hepatocyte nuclear factor 4 A (HNF4A) controls the metabolic features of several endodermal epithelia. Both HNF4A and HNF4G are redundant in the intestine and it remains unclear whether HNF4A alone controls intestinal lipid metabolism. Here we show that intestinal HNF4A is not required for intestinal lipid metabolism per se, but unexpectedly influences whole-body energy expenditure in diet-induced obesity (DIO). Deletion of intestinal HNF4A caused mice to become DIO-resistant with a preference for fat as an energy substrate and energetic changes in association with white adipose tissue (WAT) beiging. Intestinal HNF4A is crucial for the fat-induced release of glucose-dependent insulinotropic polypeptide (GIP), while the reintroduction of a stabilized GIP analog rescues the DIO resistance phenotype of the mutant mice. Our study provides evidence that intestinal HNF4A plays a non-redundant role in whole-body lipid homeostasis and points to a non-cell-autonomous regulatory circuit for body-fat management.

Early Clinical Prediction of Independent Outdoor Functional Walking Capacity in a Prospective Cohort of Traumatic Spinal Cord Injury Patients.

OBJECTIVE: The first objective was to identify a method for early prediction of independent outdoor functional walking 1 yr after a traumatic spinal cord injury using the motor and sensory function derived from the International Standards for Neurological Classification of Spinal Cord Injury assessment during acute care. Then, the second objective was to develop a clinically relevant prediction rule that would be accurate, easy to use, and quickly calculated in clinical setting. DESIGN: A prospective cohort of 159 traumatic spinal cord injury patients was analyzed. Bivariate correlations were used to determine the assessment method of motor strength and sensory function as well as the specific dermatomes and myotomes best associated with independent outdoor functional walking 1 yr after injury. An easy-to-use clinical prediction rule was produced using a multivariable linear regression model. RESULTS: The highest motor strength for a given myotome (L3 and L5) and preserved light touch sensation (dermatome S1) were the best predictors of the outcome. The proposed prediction rule displayed a sensitivity of 84.21%, a specificity of 85.54%, and a global accuracy of 84.91% for classification. CONCLUSIONS: After an acute traumatic spinal cord injury, accurately predicting the ability to walk is challenging. The proposed clinical prediction rule aims to enhance previous work by identifying traumatic spinal cord injury patients who will reach a mobility level that fosters social participation and quality of life in the chronic period after the injury. TO CLAIM CME CREDITS: Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME. CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Revise the different motor and sensory function assessment methods used for prognostication of walking after an acute traumatic spinal cord injury; (2) Identify clinical factors that are significantly associated with functional walking 1 yr after a traumatic spinal cord injury; and (3) Accurately estimate the likelihood of reaching independent outdoor functional walking in the chronic phase after an acute traumatic spinal cord injury. LEVEL: Advanced. ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

NCOR1 Sustains Colorectal Cancer Cell Growth and Protects against Cellular Senescence.

NCOR1 is a corepressor that mediates transcriptional repression through its association with nuclear receptors and specific transcription factors. Some evidence supports a role for NCOR1 in neonatal intestinal epithelium maturation and the maintenance of epithelial integrity during experimental colitis in mice. We hypothesized that NCOR1 could control colorectal cancer cell proliferation and tumorigenicity. Conditional intestinal epithelial deletion of Ncor1 in ApcMin/+ mice resulted in a significant reduction in polyposis. RNAi targeting of NCOR1 in Caco-2/15 and HT-29 cell lines led to a reduction in cell growth, characterized by cellular senescence associated with a secretory phenotype. Tumor growth of HT-29 cells was reduced in the absence of NCOR1 in the mouse xenografts. RNA-seq transcriptome profiling of colon cancer cells confirmed the senescence phenotype in the absence of NCOR1 and predicted the occurrence of a pro-migration cellular signature in this context. SOX2, a transcription factor essential for pluripotency of embryonic stem cells, was induced under these conditions. In conclusion, depletion of NCOR1 reduced intestinal polyposis in mice and caused growth arrest, leading to senescence in human colorectal cell lines. The acquisition of a pro-metastasis signature in the absence of NCOR1 could indicate long-term potential adverse consequences of colon-cancer-induced senescence.

Clinical judgment is a cornerstone for validating and using clinical prediction rules: a head-to-head study on ambulation outcomes for spinal cord injured patients.

STUDY DESIGN: Retrospective comparative study. OBJECTIVE: Clinical prediction rules (CPRs) are an effervescent topic in the medical literature. Recovering ambulation after a traumatic spinal cord injury (tSCI) is a priority for patients and multiple CPRs have been proposed for predicting ambulation outcomes. Our objective is to confront clinical judgment to an established CPR developed for patients with tSCI. SETTINGS: Level one trauma center specialized in tSCI and its affiliated rehabilitation center. METHOD: In this retrospective comparative study, six physicians had to predict the ambulation outcome of 68 patients after a tSCI based on information from the acute hospitalization. Ambulation was also predicted according to the CPR of van Middendorp (CPR-vM). The success rate of the CPR-vM and clinicians to predict ambulation was compared using criteria of 5% for defining clinical significance, and a level of statistical significance of 0.05 for bilateral McNemar tests. RESULTS: There was no statistical difference between the overall performance of physicians (success rate of 79%) and of the CPR-vM (81%) for predicting ambulation. The differences between the CPR-vM and physicians varied clinically and significantly with the level of experience, clinical setting, and field of expertise. CONCLUSION: Confronting CPRs with the judgment of a group of clinicians should be an integral part of the design and validation of CPRs. Head-to-head comparison of CPRs with clinicians is also a cornerstone for defining the optimal strategy for translation into the clinical practice, and for defining which clinician and specific clinical context would benefit from using the CPR.

Evaluation of the Safety of Intravenous Thiamine Administration in a Large Academic Medical Center.

BACKGROUND/OBJECTIVE: Previous literature describes increased incidence of infusion-related reactions when administering thiamine doses greater than 100 mg as an intravenous (IV) push. The purpose of this evaluation was to assess the safety of administering higher doses of thiamine as IV push compared to infusion. METHODS: A single-center, retrospective review was performed from June to October 2017. Included patients were aged 18 years or older and received 1 dose of IV thiamine 200 mg or greater. Patients were divided into 2 groups: group 1 included patients who received 200-mg IV push and, group 2 included patients who received any dose greater than 200 mg. The primary objective was to quantify and compare rate of adverse reactions between the 2 groups. Institutional thiamine prescribing practices were examined. Wilcoxon Rank Sum and Fischer exact tests were performed. RESULTS: Sixty-six percent of patients were male, and the median age was 55 years (interquartile range [IQR]: 44-63). Fifty percent received 200-mg IV push, 20% received a combination of IV infusion and IV push, and 30% received IV infusion. Adverse reactions possibly due to thiamine administration occurred in 4 (2.0%) patients. One patient received 200 mg via IV infusion, while 3 received 200 mg via IV push. There was no significant difference in adverse reaction rate between IV push and IV infusion administrations (P = .640). CONCLUSION: Our results support administering thiamine doses of 200 mg or less as an IV push. Given lack of robust safety data, it is recommended to continue to dilute doses greater than 200 mg and infuse over 30 minutes.

Impact of embedded medication assistance program specialists on medication access in outpatient oncology clinics.

INTRODUCTION: Medication prior authorizations (PA) required by insurance payers can be time-consuming to complete and may lead to delays in treatment for cancer patients. The primary objective of this study is to assess the impact of Medication Assistance Program (MAP) specialists embedded in adult hematology and oncology clinics on the PA and financial assistance process. METHODS: This was a retrospective chart review study performed at a large academic medical center that examined medication referrals completed by MAP specialists in four hematology and oncology clinics. The primary outcome was the median PA turnaround time, defined as time from initial referral creation to final referral completion. Secondary outcomes assessed median turnaround time for financial assistance programs and total patient savings. RESULTS: A total of 176 prior authorization, 92 manufacturer patient assistance program (PAP), and 37 copay assistance referrals were completed. The median turnaround times were 24, 154, and 19 hours for PA, manufacturer PAP, and copay assistance program referrals, respectively. Total cost savings amounted to over $1.8 million for patients approved to receive medications through manufacturer PAPs. CONCLUSIONS: Embedding MAP specialists in adult hematology/oncology clinics supports an efficient and timely process for PA approvals while also providing patient cost-savings.

Rapid tumor vaccine using Toll-like receptor-activated ovarian cancer ascites monocytes.

BACKGROUND: Novel therapeutic strategies in ovarian cancer (OC) are needed as the survival rate remains dismally low. Although dendritic cell-based cancer vaccines are effective in eliciting therapeutic responses, their complex and costly manufacturing process hampers their full clinical utility outside specialized clinics. Here, we describe a novel approach of generating a rapid and effective cancer vaccine using ascites-derived monocytes for treating OC. METHODS: Using the ID8 mouse ovarian tumor model and OC patient samples, we isolated ascites monocytes and evaluated them with flow cytometry, Luminex cytokine and chemokine array analysis, ex vivo cocultures with T cells, in vivo tumor challenge and T cell transfer experiments, RNA-sequencing and mass spectrometry. RESULTS: We demonstrated the feasibility of isolating ascites monocytes and restoring their ability to function as bona fide antigen-presenting cells (APCs) with Toll-like receptor (TLR) 4 lipopolysaccharide and TLR9 CpG-oligonucleotides, and a blocking antibody to interleukin-10 receptor (IL-10R Ab) in the ID8 model. The ascites monocytes were laden with tumor antigens at a steady state in vivo. After a short 48 hours activation, they upregulated maturation markers (CD80, CD86 and MHC class I) and demonstrated strong ex vivo T cell stimulatory potential and effectively suppressed tumor and malignant ascites in vivo. They also induced protective long-term T cell memory responses. To evaluate the translational potential of this approach, we isolated ascites monocytes from stage III/IV chemotherapy-naïve OC patients. Similarly, the human ascites monocytes presented tumor-associated antigens (TAAs), including MUC1, ERBB2, mesothelin, MAGE, PRAME, GPC3, PMEL and TP53 at a steady state. After a 48-hour treatment with TLR4 and IL-10R Ab, they efficiently stimulated oligoclonal tumor-associated lymphocytes (TALs) with strong reactivity against TAAs. Importantly, the activated ascites monocytes retained their ability to activate TALs in the presence of ascitic fluid. CONCLUSIONS: Ascites monocytes are naturally loaded with tumor antigen and can perform as potent APCs following short ex vivo activation. This novel ascites APC vaccine can be rapidly prepared in 48 hours with a straightforward and affordable manufacturing process, and would be an attractive therapeutic vaccine for OC.

Characterization of the medication regimen complexity index in high-utilizer, adult psychiatric patients.

INTRODUCTION: Few studies have examined the role of medication-related factors in psychiatric readmissions. Our objective was to characterize the medication regimen complexity index (MRCI) and assess its association with psychiatric hospital readmission frequency and time to readmission in a high-utilizer psychiatric cohort. METHODS: Adult patients admitted between July 2012 and March 2014 were identified if discharged from an inpatient psychiatry service with greater than or equal to 5 psychiatric readmissions or at least one 30-day readmission. Complexity of the medication regimen was determined using a validated MRCI electronic capture tool. RESULTS: One hundred sixty-eight patients were included. Average MRCI for all readmissions was 7.09 for psychotropic medications, 5.90 for other prescription medications, 2.98 for over the counter, and 16.00 for total medications. Ages greater than 65 years old and female sex were associated with higher total MRCI scores. Average MRCI for psychotropic medications and average psychotropic medication count, along with depression diagnosis, were found to be significantly associated with average time between each readmission but not with readmission frequency. An average total MRCI score greater than 19.7, when broken down by percentiles, was associated with a shorter time to readmission. DISCUSSION: Psychotropic regimen complexity, psychotropic medication count, total MRCI greater than 19.7, and a diagnosis of depression may contribute to a shorter time to readmission in adult psychiatric patients with a history of frequent readmissions. Future studies are needed to confirm findings and evaluate clinical significance and impact.

Multi-omics Reveal that c-Src Modulates the Mitochondrial Phosphotyrosine Proteome and Metabolism According to Nutrient Availability.

BACKGROUND/AIMS: Src kinase family members, including c-Src, are involved in numerous signaling pathways and have been observed inside different cellular compartments. Notably, c-Src modulates carbohydrate and fatty acid metabolism and is involved in the metabolic rewiring of cancer cells. This kinase is found within mitochondria where it targets different proteins to impact on the organelle functions and overall metabolism. Surprisingly, no global metabolic characterization of Src has been performed although c-Src knock-out mice have been available for 30 years. Considering that c-Src is sensitive to various metabolites, c-Src might represent a crucial player in metabolic adjustments induced by nutrient stress. The aim of this work was to characterize the impact of c-Src on mitochondrial activity and overall metabolism using multi-omic characterization. METHODS: Src+/+ and Src-/- mice were fed ad libitum or fasted during 24h and were then analyzed using multi-omics. RESULTS: We observed that deletion of c-Src is linked to lower phosphorylation of Y412-NDUFA8, inhibition of oxygen consumption and accumulation of metabolites involved in glycolysis, TCA cycle and amino acid metabolism in mice fed ad libitum. Finally, metabolomics and (phosphotyrosine) proteomics are differently impacted by Src according to nutrient availability. CONCLUSION: The findings presented here highlight that c-Src reduces mitochondrial metabolism and impacts the metabolic adjustment induced by nutrient stress.

Suprastyloid Crest of the Radius in Wrist Ultrasonography: A Bony Prominence Not to Mistake for Lister's Tubercle.

N/A.

EZH2 Inhibition Sensitizes CARM1-High, Homologous Recombination Proficient Ovarian Cancers to PARP Inhibition.

In response to DNA double-strand breaks, MAD2L2-containing shieldin complex plays a critical role in the choice between homologous recombination (HR) and non-homologous end-joining (NHEJ)-mediated repair. Here we show that EZH2 inhibition upregulates MAD2L2 and sensitizes HR-proficient epithelial ovarian cancer (EOC) to poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor in a CARM1-dependent manner. CARM1 promotes MAD2L2 silencing by driving the switch from the SWI/SNF complex to EZH2 through methylating the BAF155 subunit of the SWI/SNF complex on the MAD2L2 promoter. EZH2 inhibition upregulates MAD2L2 to decrease DNA end resection, which increases NHEJ and chromosomal abnormalities, ultimately causing mitotic catastrophe in PARP inhibitor treated HR-proficient cells. Significantly, EZH2 inhibitor sensitizes CARM1-high, but not CARM-low, EOCs to PARP inhibitors in both orthotopic and patient-derived xenografts.

Evaluation of telepharmacy and the use of a gravimetric technology-assisted workflow system for remote sterile product pharmacist checks.

PURPOSE: To evaluate the impact of remote sterile product pharmacist checks when used with a gravimetric-based technology-assisted workflow (TAWF) system on product checking accuracy, pharmacist review time, workload sharing, cost savings, and staff perceptions. METHODS: A double-arm, prospective study was conducted at 4 pharmacy locations for a 90-day period. Each compounded sterile product (CSP) checked by a remote pharmacist was also checked by a local pharmacist at the site of CSP preparation. An anonymous, online survey was emailed to staff before and after implementation to evaluate perceptions of the accuracy, timeliness, safety, potential impact, and value of the remote process. RESULTS: There was no statistically significant difference in the numbers of errors detected through the remote process and through the current, nonremote process (P = 0.177). The median pharmacist review time in the local process was significantly lower (P < 0.001). Remote pharmacists in the study workflow verified 30.4% of the total number of CSPs verified in the 90-day period. Annualized cost savings were calculated to be $23,770.08. Percent agreement increased from the preimplementation to the postimplementation period for survey questions about the safety of the remote process, opportunity for workload sharing, and optimization of current workflow. Percent agreement decreased for questions about the accuracy, timeliness, and value of the remote process and its impact on job security. CONCLUSION: The study demonstrated that with use of a gravimetric-based TAWF system, there was no difference in the accuracy and safety of sterile product pharmacist checks performed remotely and those performed at the product preparation site. In addition, the remote process allows for opportunities for workload sharing and cost savings.

NAMPT Inhibition Suppresses Cancer Stem-like Cells Associated with Therapy-Induced Senescence in Ovarian Cancer.

Epithelial ovarian cancer (EOC) is the most lethal of gynecologic malignancies. The standard-of-care treatment for EOC is platinum-based chemotherapy such as cisplatin. Platinum-based chemotherapy induces cellular senescence. Notably, therapy-induced senescence contributes to chemoresistance by inducing cancer stem-like cells (CSC). However, therapeutic approaches targeting senescence-associated CSCs remain to be explored. Here, we show that nicotinamide phosphoribosyltransferase (NAMPT) inhibition suppresses senescence-associated CSCs induced by platinum-based chemotherapy in EOC. Clinically applicable NAMPT inhibitors suppressed the outgrowth of cisplatin-treated EOC cells both in vitro and in vivo. Moreover, a combination of the NAMPT inhibitor FK866 and cisplatin improved the survival of EOC-bearing mice. These phenotypes correlated with inhibition of the CSCs signature, which consists of elevated expression of ALDH1A1 and stem-related genes, high aldehyde dehydrogenase activity, and CD133 positivity. Mechanistically, NAMPT regulates EOC CSCs in a paracrine manner through the senescence-associated secretory phenotype. Our results suggest that targeting NAMPT using clinically applicable NAMPT inhibitors, such as FK866, in conjunction with platinum-based chemotherapy represents a promising therapeutic strategy by suppressing therapy-induced senescence-associated CSCs. SIGNIFICANCE: This study highlights the importance of NAMPT-mediated NAD+ biosynthesis in the production of cisplatin-induced senescence-associated cancer stem cells, as well as tumor relapse after cisplatin treatment.

Intramitochondrial Src kinase links mitochondrial dysfunctions and aggressiveness of breast cancer cells.

High levels and activity of Src kinase are common among breast cancer subtypes, and several inhibitors of the kinase are currently tested in clinical trials. Alterations in mitochondrial activity is also observed among the different types of breast cancer. Src kinase is localized in several subcellular compartments, including mitochondria where it targets several proteins to modulate the activity of the organelle. Although the subcellular localization of other oncogenes modulates the potency of known treatments, nothing is known about the specific role of intra-mitochondrial Src (mtSrc) in breast cancer. The aim of this work was to determine whether mtSrc kinase has specific impact on breast cancer cells. We first observed that activity of mtSrc is higher in breast cancer cells of the triple negative subtype. Over-expression of Src specifically targeted to mitochondria reduced mtDNA levels, mitochondrial membrane potential and cellular respiration. These alterations of mitochondrial functions led to lower cellular viability, shorter cell cycle and increased invasive capacity. Proteomic analyses revealed that mtSrc targets the mitochondrial single-stranded DNA-binding protein, a regulator of mtDNA replication. Our findings suggest that mtSrc promotes aggressiveness of breast cancer cells via phosphorylation of mitochondrial single-stranded DNA-binding protein leading to reduced mtDNA levels and mitochondrial activity. This study highlights the importance of considering the subcellular localization of Src kinase in the development of potent therapy for breast cancer.