Decoding Endothelial MPL and JAK2V617F Mutation: Insight Into Cardiovascular Dysfunction in Myeloproliferative Neoplasms.

BACKGROUND: Patients with JAK2V617F-positive myeloproliferative neoplasms (MPNs) and clonal hematopoiesis of indeterminate potential face a significantly elevated risk of cardiovascular diseases. Endothelial cells carrying the JAK2V617F mutation have been detected in many patients with MPN. In this study, we investigated the molecular basis for the high incidence of cardiovascular complications in patients with MPN. METHODS: We investigated the impact of endothelial JAK2V617F mutation on cardiovascular disease development using both transgenic murine models and MPN patient-derived induced pluripotent stem cell lines. RESULTS: Our investigations revealed that JAK2V617F mutant endothelial cells promote cardiovascular diseases under stress, which is associated with endothelial-to-mesenchymal transition and endothelial dysfunction. Importantly, we discovered that inhibiting the endothelial TPO (thrombopoietin) receptor MPL (myeloproliferative leukemia virus oncogene) suppressed JAK2V617F-induced endothelial-to-mesenchymal transition and prevented cardiovascular dysfunction caused by mutant endothelial cells. Notably, the endothelial MPL receptor is not essential for the normal physiological regulation of blood cell counts and cardiac function. CONCLUSIONS: JAK2V617F mutant endothelial cells play a critical role in the development of cardiovascular diseases in JAK2V617F-positive MPNs, and endothelial MPL could be a promising therapeutic target for preventing or ameliorating cardiovascular complications in these patients.

Factors Influencing Implementation of the Commission on Cancer's Breast Synoptic Operative Report (Alliance A20_Pilot9).

BACKGROUND: The technical aspects of cancer surgery have a significant impact on patient outcomes. To monitor surgical quality, in 2020, the Commission on Cancer (CoC) revised its accreditation standards for cancer surgery and introduced the synoptic operative reports (SORs). The standardization of SORs holds promise, but successful implementation requires strategies to address key implementation barriers. This study aimed to identify the barriers and facilitators to implementing breast SOR within diverse CoC-accredited programs. METHODS: In-depth semi-structured interviews were conducted with 31 health care professionals across diverse CoC-accredited sites. The study used two comprehensive implementation frameworks to guide data collection and analysis. RESULTS: Successful SOR implementation was impeded by disrupted workflows, surgeon resistance to change, low prioritization of resources, and poor flow of information despite CoC's positive reputation. Participants often lacked understanding of the requirements and timeline for breast SOR and were heavily influenced by prior experiences with templates and SOR champion relationships. The perceived lack of monetary benefits (to obtaining CoC accreditation) together with the significant information technology (IT) resource requirements tempered some of the enthusiasm. Additionally, resource constraints and the redirection of personnel during the COVID-19 pandemic were noted as hurdles. CONCLUSIONS: Surgeon behavior and workflow change, IT and personnel resources, and communication and networking strategies influenced SOR implementation. During early implementation and the implementation planning phase, the primary focus was on achieving buy-in and initiating successful roll-out rather than effective use or sustainment. These findings have implications for enhancing standardization of surgical cancer care and guidance of future strategies to optimize implementation of CoC accreditation standards.

JAK2V617F Mutant Megakaryocytes Contribute to Hematopoietic Aging in a Murine Model of Myeloproliferative Neoplasm.

Megakaryocytes (MKs) is an important component of the hematopoietic niche. Abnormal MK hyperplasia is a hallmark feature of myeloproliferative neoplasms (MPNs). The JAK2V617F mutation is present in hematopoietic cells in a majority of patients with MPNs. Using a murine model of MPN in which the human JAK2V617F gene is expressed in the MK lineage, we show that the JAK2V617F-bearing MKs promote hematopoietic stem cell (HSC) aging, manifesting as myeloid-skewed hematopoiesis with an expansion of CD41+ HSCs, a reduced engraftment and self-renewal capacity, and a reduced differentiation capacity. HSCs from 2-year-old mice with JAK2V617F-bearing MKs were more proliferative and less quiescent than HSCs from age-matched control mice. Examination of the marrow hematopoietic niche reveals that the JAK2V617F-bearing MKs not only have decreased direct interactions with hematopoietic stem/progenitor cells during aging but also suppress the vascular niche function during aging. Unbiased RNA expression profiling reveals that HSC aging has a profound effect on MK transcriptomic profiles, while targeted cytokine array shows that the JAK2V617F-bearing MKs can alter the hematopoietic niche through increased levels of pro-inflammatory and anti-angiogenic factors. Therefore, as a hematopoietic niche cell, MKs represent an important connection between the extrinsic and intrinsic mechanisms for HSC aging.

Invasive squamous cell carcinoma of the breast associated with breast augmentation implant capsule.

Primary squamous cell carcinoma (SCC) of the breast is rare, representing less than 0.1% of all breast cancers. To date, there have been 20 reported cases of SCC associated with breast augmentation, usually in patients with long-standing implants. A patient is reported here with primary squamous carcinoma of the breast associated with textured saline implants. Due to the paucity of cases, there is limited information on the incidence and management of implant-associated SCC of the breast.

Short-term and long-term financial toxicity from breast cancer treatment: a qualitative study.

PURPOSE: The rising cost of breast cancer treatment has increased patients' financial burden, intensifying an already stressful treatment process. Although researchers increasingly recognize the harmful impact of medical and nonmedical costs associated with cancer treatment, understanding patients' perspectives of financial toxicity is limited. We aimed to explore the topic of financial toxicity through the lived experiences of patients with breast cancer from groups at risk of social and economic marginalization. METHODS: We conducted semi-structured interviews with 50 women with breast cancer from four specific groups: Black women, Medicaid enrollees, rural residents, and women age ≤ 40. We transcribed, coded, and analyzed the data using deductive and inductive approaches. RESULTS: Two overarching themes captured patients' experiences of financial toxicity: short-term and long-term impacts. Short-term stressors included direct medical (e.g., co-pays, premiums), nonmedical (e.g., transportation, lodging), and indirect (e.g., job loss, reduced work hours) costs. Early in their treatments, patients' focus on survival took precedence over financial concerns. However, as the treatment course progressed, fear of consequences from compounding costs of care and financial distress negatively impacted patients' lifestyles and outlooks for the future. CONCLUSION: Programs addressing financial toxicity that look beyond early-phase interventions are needed. Specifically, patients struggling with the accumulation of treatment costs and the resultant stress require ongoing support. Long-term support is especially needed for groups vulnerable to financial instability and social marginalization.

Oxygen-independent disulfide bond formation in VEGF-A and CA9.

Low levels of oxygen (hypoxia) occurs in many (patho)physiological situations. Adaptation to hypoxia is in part mediated by proteins expressed in the extracellular space that mature in the endoplasmic reticulum (ER) prior to traversing the secretory pathway. The majority of such ER cargo proteins require disulfide bonds for structural stability. Disulfide bonds are formed co- and posttranslationally in a redox relay that requires a terminal electron acceptor such as oxygen. We have previously demonstrated that some ER cargo proteins such as low-density lipoprotein receptor (LDLR) and influenza hemagglutinin (Flu-HA) are unable to complete disulfide bond formation in the absence of oxygen, limiting their ability to pass ER quality control and their ultimate expression. Here, using radioactive pulse-chase immunoprecipitation analysis, we demonstrate that hypoxia-induced ER cargo proteins such as carbonic anhydrase 9 (CA9) and vascular endothelial growth factor A (VEGF-A) complete disulfide bond formation and mature with similar kinetics under hypoxia and normoxia. A global in silico analysis of ER cargo revealed that hypoxia-induced proteins on average contain fewer free cysteines and shorter-range disulfide bonds in comparison to other ER cargo proteins. These data demonstrate the existence of alternative electron acceptors to oxygen for disulfide bond formation in cellulo. However, the ability of different proteins to utilize an oxygen-independent pathway for disulfide bond formation varies widely, contributing to differential gene expression in hypoxia. The superior ability of hypoxia-induced proteins such as VEGF-A and CA9 to mature in hypoxia may be conferred by a simpler disulfide architecture.

Mammalian Y chromosomes retain widely expressed dosage-sensitive regulators.

The human X and Y chromosomes evolved from an ordinary pair of autosomes, but millions of years ago genetic decay ravaged the Y chromosome, and only three per cent of its ancestral genes survived. We reconstructed the evolution of the Y chromosome across eight mammals to identify biases in gene content and the selective pressures that preserved the surviving ancestral genes. Our findings indicate that survival was nonrandom, and in two cases, convergent across placental and marsupial mammals. We conclude that the gene content of the Y chromosome became specialized through selection to maintain the ancestral dosage of homologous X-Y gene pairs that function as broadly expressed regulators of transcription, translation and protein stability. We propose that beyond its roles in testis determination and spermatogenesis, the Y chromosome is essential for male viability, and has unappreciated roles in Turner's syndrome and in phenotypic differences between the sexes in health and disease.

Comparative toxicoproteogenomics of mouse and rat liver identifies TCDD-resistance genes.

The aryl hydrocarbon receptor (AHR) mediates many toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, the AHR alone does not explain the widely different outcomes among organisms. To identify the other factors involved, we evaluated three transgenic mouse lines, each expressing a different rat AHR isoform (rWT, DEL, and INS) providing widely different resistance to TCDD toxicity, as well as C57BL/6 and DBA/2 mice which exhibit a ~ tenfold divergence in TCDD sensitivity (exposures of 5-1000 µg/kg TCDD). We supplement these with whole-genome sequencing, together with transcriptomic and proteomic analyses of the corresponding rat models, Long-Evans (L-E) and Han/Wistar (H/W) rats (having a ~ 1000-fold difference in their TCDD sensitivities; 100 µg/kg TCDD), to identify genes associated with TCDD-response phenotypes. Overall, we identified up to 50% of genes with altered mRNA abundance following TCDD exposure are associated with a single AHR isoform (33.8%, 11.7%, 5.2% and 0.3% of 3076 genes altered unique to rWT, DEL, C57BL/6 and INS respectively following 1000 µg/kg TCDD). Hepatic Pxdc1 was significantly repressed in all three TCDD-sensitive animal models (C57BL/6 and rWT mice, and L-E rat) after TCDD exposure. Three genes, including Cxxc5, Sugp1 and Hgfac, demonstrated different AHRE-1 (full) motif occurrences within their promoter regions between rat strains, as well as different patterns of mRNA abundance. Several hepatic proteins showed parallel up- or downward alterations with their RNAs, with three genes (SNRK, IGTP and IMPA2) showing consistent, strain-dependent changes. These data show the value of integrating genomic, transcriptomic and proteomic evidence across multi-species models in toxicologic studies.

Contrast-Enhanced Ultrasound Imaging of Breast Masses: Adjunct Tool to Decrease the Number of False-Positive Biopsy Results.

OBJECTIVES: This pilot study evaluated use of contrast-enhanced ultrasound (CEUS) to reduce the number of benign breast masses recommended for biopsy. METHODS: This prospective study included 131 consenting women, from October 2016 to June 2017, with American College of Radiology Breast Imaging Reporting and Data System category 4a, 4b, and 4c masses detected by mammography, conventional ultrasound (US), or both. Contrast-enhanced US examinations (using intravenous injection of perflutren lipid microspheres or sulfur hexafluoride lipid-type A microspheres) were performed before biopsy. Qualitative and quantitative CEUS parameters were compared with reference standard histopathologic results from biopsy of 131 masses. RESULTS: There were 109 benign, 6 high-risk, and 16 malignant masses, with a median size of 12 mm (range, 4 to 48 mm) on conventional US imaging. Of 131 masses, 93 (71%) enhanced on CEUS imaging, including 73 of 109 (67%) benign, 6 of 6 (100%) high-risk, and 14 of 16 (87.5%) malignant. Thirty-eight lesions did not enhance, including 36 of 109 (33%) benign and 2 of 16 (12.5%) malignant. Prediction models using recursive petitioning revealed that CEUS may reduce 31% (95% confidence interval, 23%, 40%) of benign biopsies for masses that are: nonenhancing with circumscribed margins or enhancing with an oval shape and homogeneous enhancement. Quantitative parameters indicated that benign masses had the longest time to peak (P = .078), highest time-to-peak ratio of mass to background (P = .036), lowest peak intensity (P = .021), and smallest difference in peak intensity between the mass and background (P = .079) compared to high-risk and malignant lesions. CONCLUSIONS: Contrast-enhanced US may be a valuable modality that can be used to predict benign pathologic results of breast masses, thereby reducing the number of biopsies.

Natural variation in genome architecture among 205 Drosophila melanogaster Genetic Reference Panel lines.

The Drosophila melanogaster Genetic Reference Panel (DGRP) is a community resource of 205 sequenced inbred lines, derived to improve our understanding of the effects of naturally occurring genetic variation on molecular and organismal phenotypes. We used an integrated genotyping strategy to identify 4,853,802 single nucleotide polymorphisms (SNPs) and 1,296,080 non-SNP variants. Our molecular population genomic analyses show higher deletion than insertion mutation rates and stronger purifying selection on deletions. Weaker selection on insertions than deletions is consistent with our observed distribution of genome size determined by flow cytometry, which is skewed toward larger genomes. Insertion/deletion and single nucleotide polymorphisms are positively correlated with each other and with local recombination, suggesting that their nonrandom distributions are due to hitchhiking and background selection. Our cytogenetic analysis identified 16 polymorphic inversions in the DGRP. Common inverted and standard karyotypes are genetically divergent and account for most of the variation in relatedness among the DGRP lines. Intriguingly, variation in genome size and many quantitative traits are significantly associated with inversions. Approximately 50% of the DGRP lines are infected with Wolbachia, and four lines have germline insertions of Wolbachia sequences, but effects of Wolbachia infection on quantitative traits are rarely significant. The DGRP complements ongoing efforts to functionally annotate the Drosophila genome. Indeed, 15% of all D. melanogaster genes segregate for potentially damaged proteins in the DGRP, and genome-wide analyses of quantitative traits identify novel candidate genes. The DGRP lines, sequence data, genotypes, quality scores, phenotypes, and analysis and visualization tools are publicly available.

Accuracy of Contrast-Enhanced Ultrasound Compared With Magnetic Resonance Imaging in Assessing the Tumor Response After Neoadjuvant Chemotherapy for Breast Cancer.

OBJECTIVES: This pilot study compared contrast enhanced ultrasound (US) with contrast-enhanced magnetic resonance imaging (MRI) in assessing the treatment response in patients with breast cancer receiving preoperative neoadjuvant chemotherapy (NAC). METHODS: This prospective Institutional Review Board-approved and Health Insurance Portability and Accountability Act-compliant study included 30 patients, from January 2014 to October 2015, with invasive breast cancer detected by mammography, conventional US imaging, or both and scheduled for NAC. Informed consent was obtained. Contrast-enhanced US (perflutren lipid microspheres, 10 µL/kg) and MRI (gadopentetate dimeglumine, 0.1 mmol/kg) scans were performed at baseline before starting NAC and after completing NAC before surgery. Results of the imaging techniques were compared with each other and with histopathologic findings obtained at surgery using the Spearman correlation. Tumor size and enhancement parameters were compared for 15 patients with contrast-enhanced US, MRI, and surgical pathologic findings. RESULTS: The median tumor size at baseline was 3.1 cm on both contrast-enhanced US and MRI scans. The Spearman correlation showed strong agreement in tumor size at baseline between contrast-enhanced US and MRI (r = 0.88; P < .001) but less agreement in tumor size after NAC (r = 0.66; P = .004). Trends suggested that contrast-enhanced US (r = 0.75; P < .001) had a better correlation than MRI (r = 0.42; P = .095) with tumor size at surgery. Contrast-enhanced US was as effective as MRI in predicting a complete pathologic response (4 patients; 75.0% accuracy for both) and a non-complete pathologic response (11 patients; 72.7% accuracy for both). CONCLUSIONS: Contrast enhanced US is a valuable imaging modality for assessing the treatment response in patients receiving NAC and had a comparable correlation as MRI with breast cancer size at surgery.

Quantitative Measurement of Histone Tail Acetylation Reveals Stage-Specific Regulation and Response to Environmental Changes during Drosophila Development.

Histone modification plays a major role in regulating gene transcription and ensuring the healthy development of an organism. Numerous studies have suggested that histones are dynamically modified during developmental events to control gene expression levels in a temporal and spatial manner. However, the study of histone acetylation dynamics using currently available techniques is hindered by the difficulty of simultaneously measuring acetylation of the numerous potential sites of modification present in histones. Here, we present a methodology that allows us to combine mass spectrometry-based histone analysis with Drosophila developmental genetics. Using this system, we characterized histone acetylation patterns during multiple developmental stages of the fly. Additionally, we utilized this analysis to characterize how treatments with pharmacological agents or environmental changes such as γ-irradiation altered histone acetylation patterns. Strikingly, γ-irradiation dramatically increased the level of acetylation at H3K18, a site linked to DNA repair via nonhomologous end joining. In mutant fly strains deficient in DNA repair proteins, however, this increase in the level of H3K18 acetylation was lost. These results demonstrate the efficacy of our combined mass spectrometry system with a Drosophila model system and provide interesting insight into the changes in histone acetylation during development, as well as the effects of both pharmacological and environmental agents on global histone acetylation.

ED breast cases and other breast emergencies.

Patients with pathologic processes of the breast commonly present in the Emergency Department (ED). Familiarity with the imaging and management of the most common entities is essential for the radiologist. Additionally, it is important to understand the limitations of ED imaging and management in the acute setting and to recognize when referrals to a specialty breast center are necessary. The goal of this article is to review the clinical presentations, pathophysiology, imaging, and management of emergency breast cases and common breast pathology seen in the ED.

Radiologist's role in breast cancer staging: providing key information for clinicians.

Breast cancer is the second leading cause of cancer death in women, exceeded only by lung cancer, and the 5-year survival rate is largely dependent on disease stage. The American Joint Committee on Cancer (AJCC) staging system for breast cancer (7th edition) provides a tumor-node-metastasis (TNM) classification scheme for breast cancer that is important for determining prognosis and treatment. Ascertaining the correct stage of breast cancer can be challenging, and the importance of the radiologist's role has increased over the years. The radiologist should understand how breast cancer stage is assigned and should be familiar with the AJCC's TNM classification scheme. The authors review the AJCC's TNM staging system for breast cancer with emphasis on clinical and preoperative staging, the different imaging modalities used in staging, and the key information that should be conveyed to clinicians. Radiologic information that may alter stage, prognosis, or treatment includes tumor size; number of tumor lesions; total span of disease; regional nodal status (axillary levels I-III, internal mammary, supraclavicular); locoregional invasion (involvement of the pectoralis muscle, skin, nipple, or chest wall); and distant metastases to bone, lung, brain, and liver, among other anatomic structures.

Comparison of the POP-Q examination, transvaginal ultrasound, and direct anatomic measurement of cervical length.

INTRODUCTION AND HYPOTHESIS: Our objective was to determine the relationship between the Pelvic Organ Prolapse Quantification (POP-Q) examination for determining cervical length (CL) and CL at hysterectomy. Secondary objectives were to define cervical elongation using both measures in a urogynecologic population, determine the relationship between POP-Q estimate and CL on ultrasound (US) and examine the interobserver reliability of each mode of measurement. METHODS: This was a prospective cohort study of women scheduled for hysterectomy at the Los Angeles County + University of Southern California (LAC + USC) medical center. CLs were measured by POP-Q and at the time of hysterectomy. Transvaginal US CLs were determined when available. Exam CL (eCL) was compared with anatomic (aCL) and US (uCL) CL. Repeat measures of eCL, uCL, and aCL were all compared for interobserver reliability. RESULTS: The study enrolled 151 women. Median eCL was 3.0 cm (0.5-9.0) (n = 149); average uCL was 2.3 cm ± 0.7 (n = 108), average aCL 2.8 cm ± 1.1 (n = 87); eCL correlated fairly with aCL (r = 0.3, p = 0.005, n = 88) but poorly with uCL (r = -0.13, p = 0.18, n = 105); uCL correlated poorly with aCL (r = 0.19, p = 0.14, n = 64). Interobserver reliability for eCL and aCL were good to excellent (eCL α=0.881; aCL α=0.889) but for uCL adequate (α=0.699). The 97.5 percentile cutoff for aCL was 5.0 cm and for eCL 8.0 cm. CONCLUSIONS: The POP-Q examination estimate of CL correlates fairly with aCL at the time of hysterectomy; uCL does not appear to correlate with aCL or eCL. Cervical elongation may be defined as an anatomic length of 5.0 cm or a POP-Q estimate of 8.0 cm.

Deciphering the differential impact of thrombopoietin/MPL signaling on hematopoietic stem/progenitor cell function in bone marrow and spleen.

Thrombopoietin (TPO) and its receptor MPL play crucial roles in hematopoietic stem cell (HSC) function and platelet production. However, the precise effects of TPO/MPL signaling on HSC regulation in different hematopoietic niches remain unclear. Here, we investigated the effects of TPO/MPL ablation on marrow and splenic hematopoiesis in TPO-/- and MPL-/- mice during aging. Despite severe thrombocytopenia, TPO-/- and MPL-/- mice did not develop marrow failure during a 2-year follow-up. Marrow and splenic HSCs exhibited different responses to TPO/MPL ablation and exogenous TPO treatment. Splenic niche cells compensated for marrow HSC loss in TPO-/- and MPL-/- mice by upregulating CXCL12 levels. These findings provide new insights into the complex regulation of HSCs by TPO/MPL and reveal a previously unknown link between TPO and CXCL12, two key growth factors for HSC maintenance. Understanding the distinct regulatory mechanisms between marrow and spleen hematopoiesis will help to develop novel therapeutic approaches for hematopoietic disorders.

Idiopathic Granulomatous Mastitis: Imaging Findings and Outcomes with Nonsteroidal Treatment in a Predominantly Hispanic Population.

OBJECTIVE: We describe the demographics, clinical presentation, imaging findings, and treatment response among 235 cases of biopsy-proven idiopathic granulomatous mastitis (IGM) at a single institution. METHODS: An institutional review board-approved retrospective search of the breast imaging database was performed to select patients with biopsy-proven IGM between 2017 and 2022. Retrospective review evaluated clinical presentation, imaging findings with US and mammography, and treatment recommendations (antibiotics, nonsteroidal anti-inflammatory drugs [NSAIDs], warm compresses, or observation only). Response to treatment was evaluated on follow-up US. A favorable treatment response was a decrease in size or resolution of disease on follow-up imaging. Statistical analysis using Poisson regression was performed to evaluate the clinical outcomes associated with each treatment. RESULTS: A total of 235 patients met the selection criteria with a mean age of 38 years (18 to 68). The majority of patients were Hispanic (95%, 223/235). Of all patients, 75.3% (177/235) received treatment (consisting of 1 or any combination of antibiotics, NSAIDs, warm compresses), 24.7% (58/235) were treated with observation, 78.7% (185/235) returned for follow-up imaging, and 21.3% (50/235) were lost to follow-up. Of those with follow-up imaging, disease improvement was seen in 70.3% (102/145) of patients who received treatment compared with 72.5% (29/40) of patients treated by observation alone. Multivariate analysis further showed no difference in clinical outcomes among the treatment of unifocal, multifocal, or recurrent IGM. CONCLUSION: Nonsteroidal treatment of IGM showed no significant improvement on follow-up imaging compared to treatment with observation alone in a predominantly Hispanic patient population.

Perspectives of Health Care Providers on Peer Support for Adolescents with Cancer in Pediatrics.

Health care providers (HCPs) play a key role in psychosocial care of adolescents with cancer (AWC) and present a unique perspective. This prospective study included a brief survey followed by an interview, seeking to understand HCPs' viewpoints on peer support needs of AWC. Participants were 10 multidisciplinary HCPs with 5-30 years of experience. Three key themes found were: observations made and relationships with AWC; challenges to providing support; and potential peer support interventions. HCPs want to provide peer support resources but lack adequate information. Next steps: interventions should include information dissemination to all HCPs caring for AWC.

Cysteamine dioxygenase (ADO) governs cancer cell mitochondrial redox homeostasis through proline metabolism.

2-Aminoethanethiol dioxygenase (ADO) is a thiol dioxygenase that sulfinylates cysteamine and amino-terminal cysteines in polypeptides. The pathophysiological roles of ADO remain largely unknown. Here, we demonstrate that ADO expression represents a vulnerability in cancer cells, as ADO depletion led to loss of proliferative capacity and survival in cancer cells and reduced xenograft growth. In contrast, generation of the ADO knockout mouse revealed high tolerance for ADO depletion in adult tissues. To understand the mechanism underlying ADO's essentiality in cancer cells, we characterized the cell proteome and metabolome following depletion of ADO. This revealed that ADO depletion leads to toxic levels of polyamines which can be driven by ADO's substrate cysteamine. Polyamine accumulation in turn stimulated expression of proline dehydrogenase (PRODH) which resulted in mitochondrial hyperactivity and ROS production, culminating in cell toxicity. This work identifies ADO as a unique vulnerability in cancer cells, due to its essential role in maintenance of redox homeostasis through restraining polyamine levels and proline catabolism.