Emerging structures and dynamic mechanisms of γ-secretase for Alzheimer's disease.

γ-Secretase, called "the proteasome of the membrane," is a membrane-embedded protease complex that cleaves 150+ peptide substrates with central roles in biology and medicine, including amyloid precursor protein and the Notch family of cell-surface receptors. Mutations in γ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer's disease. γ-Secretase has thus served as a critical drug target for treating familial Alzheimer's disease and the more common late-onset Alzheimer's disease as well. However, critical gaps remain in understanding the mechanisms of processive proteolysis of substrates, the effects of familial Alzheimer's disease mutations, and allosteric modulation of substrate cleavage by γ-secretase. In this review, we focus on recent studies of structural dynamic mechanisms of γ-secretase. Different mechanisms, including the "Fit-Stay-Trim," "Sliding-Unwinding," and "Tilting-Unwinding," have been proposed for substrate proteolysis of amyloid precursor protein by γ-secretase based on all-atom molecular dynamics simulations. While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-bound γ-secretase, molecular dynamics simulations on a resolved model of Notch1-bound γ-secretase that was reconstructed using the amyloid precursor protein-bound γ-secretase as a template successfully captured γ-secretase activation for proper cleavages of both wildtype and mutant Notch, being consistent with biochemical experimental findings. The approach could be potentially applied to decipher the processing mechanisms of various substrates by γ-secretase. In addition, controversy over the effects of familial Alzheimer's disease mutations, particularly the issue of whether they stabilize or destabilize γ-secretase-substrate complexes, is discussed. Finally, an outlook is provided for future studies of γ-secretase, including pathways of substrate binding and product release, effects of modulators on familial Alzheimer's disease mutations of the γ-secretase-substrate complexes. Comprehensive understanding of the functional mechanisms of γ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer's disease and perhaps Alzheimer's disease in general.

Classification and Risk Factors for Surgical Site Infections in Radical Cystectomy: A 16-Year Analysis.

Introduction: Surgical site infection (SSI) is a substantial cause of peri-operative morbidity among patients undergoing radical cystectomy (RC). The purpose of this study was to identify the risk factors of SSI after RC and to classify and characterize treatment of SSIs. Methods: We retrospectively analyzed peri-operative characteristics and SSI, for patients undergoing RC from 2007 to 2022. Patients were stratified by SSI versus no SSI and differences were assessed. Uni-variable/multi-variable logistic regression analyses were performed to identify factors associated with SSI. SSIs were categorized by the Centers for Disease Control and Prevention (CDC) type: Superficial incisional, deep incisional, and organ/space confined. Results: Three hundred and ninety-eight patients had RC, 279 open, and 119 robotic; 78 (19.6%) developed SSI. Cohorts were similar demographically. Length of stay (LOS) was longer in the SSI cohort (8.8 d versus 12.4 d, p < 0.001), and body mass index (BMI) was greater in patients with SSI (24.34 vs. 25.39, p = 0.0003). On uni-variable analysis, age, gender, Charlson Comorbidity Index, diabetes mellitus, diversion, odds ratio (OR) time, blood loss, and open versus robotic technique were not substantial SSI predictors. BMI was an independent risk factor for SSI on both uni-variable (OR: 1.07, 95% confidence interval [CI]: 1.018-1.115, p = 0.0061) and multi-variable analysis (OR: 1.06, 95% CI: 1.009-1.109, p = 0.02) for 10 (12.8%) and 24 (30.8%) superficial and deep-incisional SSIs, respectively. Superficial wound SSI was treated conservatively with 60% receiving antibiotic agents and no procedural intervention. Deep SSIs received antibiotic agents and 50% required surgical intervention. There were 44 (56.4%) organ/space SSIs, and the most common treatment was antibiotic agents (100%) and IR drain placement (30, 68.2%). Conclusion: In patients undergoing RC, BMI was an independent risk factor for SSI. Type of the surgical procedure, robotic versus open, was not predictive of SSI. LOS was longer for patients with SSI. SSI was managed differently depending on CDC classification.

Environmental damping and vibrational coupling of confined fluids within isolated carbon nanotubes.

Because of their large surface areas, nanotubes and nanowires demonstrate exquisite mechanical coupling to their surroundings, promising advanced sensors and nanomechanical devices. However, this environmental sensitivity has resulted in several ambiguous observations of vibrational coupling across various experiments. Herein, we demonstrate a temperature-dependent Radial Breathing Mode (RBM) frequency in free-standing, electron-diffraction-assigned Double-Walled Carbon Nanotubes (DWNTs) that shows an unexpected and thermally reversible frequency downshift of 10 to 15%, for systems isolated in vacuum. An analysis based on a harmonic oscillator model assigns the distinctive frequency cusp, produced over 93 scans of 3 distinct DWNTs, along with the hyperbolic trajectory, to a reversible increase in damping from graphitic ribbons on the exterior surface. Strain-dependent coupling from self-tensioned, suspended DWNTs maintains the ratio of spring-to-damping frequencies, producing a stable saturation of RBM in the low-tension limit. In contrast, when the interior of DWNTs is subjected to a water-filling process, the RBM thermal trajectory is altered to that of a Langmuir isobar and elliptical trajectories, allowing measurement of the enthalpy of confined fluid phase change. These mechanisms and quantitative theory provide new insights into the environmental coupling of nanomechanical systems and the implications for devices and nanofluidic conduits.

Plerixafor for pathogen-agnostic treatment in murine thigh infection and zebrafish sepsis.

Plerixafor is a CXCR4 antagonist approved in 2008 by the FDA for hematopoietic stem cell collection. Subsequently, plerixafor has shown promise as a potential pathogen-agnostic immunomodulator in a variety of preclinical animal models. Additionally, investigator-led studies demonstrated plerixafor prevents viral and bacterial infections in patients with WHIM syndrome, a rare immunodeficiency with aberrant CXCR4 signaling. Here, we investigated whether plerixafor could be repurposed to treat sepsis or severe wound infections, either alone or as an adjunct therapy. In a Pseudomonas aeruginosa lipopolysaccharide (LPS)-induced zebrafish sepsis model, plerixafor reduced sepsis mortality and morbidity assessed by tail edema. There was a U-shaped response curve with the greatest effect seen at 0.1 µM concentration. We used Acinetobacter baumannii infection in a neutropenic murine thigh infection model. Plerixafor did not show reduced bacterial growth at 24 h in the mouse thigh model, nor did it amplify the effects of a rifampin antibiotic therapy, in varying regimens. While plerixafor did not mitigate or treat bacterial wound infections in mice, it did reduce sepsis mortality in zebra fish. The observed mortality reduction in our LPS model of zebrafish was consistent with prior research demonstrating a mortality benefit in a murine model of sepsis. However, based on our results, plerixafor is unlikely to be successful as an adjunct therapy for wound infections. Further research is needed to better define the scope of plerixafor as a pathogen-agnostic therapy. Future directions may include the use of longer acting CXCR4 antagonists, biased CXCR4 signaling, and optimization of animal models.

A devastating case of a Balamuthia mandrillaris pediatric brain infection.

Balamuthia mandrillaris is an amoeba that causes an uncommon but deadly encephalitis, referred to as granulomatous amoebic encephalitis (GAE). The highest incidence reported worldwide has occurred in America, and within the United States, it has been highest in the Southwest affecting predominantly children and young men of Hispanic ethnicity. Clinical presentation of GAE includes fever, headache, nausea, vomiting, lethargy, irritability, stiff neck, hallucinations, photophobia, and seizures. Our patient was a Hispanic male child living in Arizona. The patient presented at 3 years of age for severe encephalitis. Symptoms included difficulty with balance, gait, and sitting up and seizure-like activity. Initial CT showed an area of decreased density consistent with edema in the right frontal and left frontoparietal lobes. Rapid progression was seen on further imaging over the length of the patient's hospital stay revealing diffusion restriction, necrosis/blood products, edema, and hemorrhage. The patient expired three weeks after onset of symptoms and one week after admission to our institution. While there are multiple biochemical techniques that can test for B. mandrillaris, they are rarely employed for multiple reasons stemming from the rare occurrence of this infection. Because of the fatal nature of this infection, we propose (1) testing should be considered if a patient presents with progressing encephalitis on imaging and other pathogenic etiologies are ruled out and (2) the threshold to treat empirically should be low due to the fatal nature of the infection.

Streptococcus canis Native Aortic Valve Endocarditis Linked to Cat Exposure: A Case Report and Review.

Streptococcus canis is an uncommon human pathogen, but documented infections have been mostly associated with exposure to dogs. There are only five documented cases of endocarditis secondary to streptococcus canis, with all cases except one documenting exposure to a canine. We present a 74-year-old male with a history of Type 2 diabetes mellitus, CKD 3, moderate aortic stenosis and remote exposure to agent orange, who was found to have Streptococcus canis native valve endocarditis without exposure to a dog. To the best of our knowledge this case is the first case of endocarditis linked to feline exposure.

Pathway to a molecular calcium methyl.

The dimeric ß-diketiminato calcium hydride, [(BDI)CaH]2 (BDI = HC{(Me)CN-2,6-iPr2C6H3}2), reacts with ZnMe2 to afford the bimetallic calcium zincate complex, [(BDI)Ca(µ-CH3)2Zn(µ-H)]2, which subsequently undergoes an intramolecular reaction to effect the formation of [(BDI)CaMe]2, a notable omission from the homologous series of ß-diketiminato alkylcalcium derivatives.

Pavlovian or associative sensitization and its biological significance.

Pavlovian conditioning is typically distinguished from sensitization but a Pavlovian conditional stimulus (CS) also results in sensitization. A Pavlovian CS can sensitize responding to a probe stimulus that is related to the unconditional stimulus (US) or to the US itself. Pavlovian sensitization has been studied in the defensive, sexual, and feeding systems. In Pavlovian sensitization, the focus is not on a conditional response (CR) directly elicited by the CS but on the response mode that is activated by the CS. Activation of a response mode increases the probability of particular responses and also increases reactivity to various stimuli. Pavlovian sensitization reflects this increased stimulus reactivity. Pavlovian sensitization helps uncover successful learning in situations where a conventional CR does not occur. Pavlovian sensitization also encourages broadening our conceptions of Pavlovian conditioning to include changes in afferent processes. Implications for biological fitness and for basic and translational research are discussed.

High-Volume Surgeons and Reducing Racial Disparities in Route of Hysterectomy.

STUDY OBJECTIVE: To examine racial disparities in route of hysterectomy and perioperative outcomes before and after expansion of high-volume minimally invasive surgeons (>10 minimally invasive hysterectomies (MIH)/year) DESIGN: Retrospective cohort study SETTING: Multi-center academic teaching institution PATIENTS: All patients who underwent a scheduled hysterectomy for benign indications during 2018 (pre-intervention) and 2022 (post-intervention) INTERVENTIONS: Recruitment of Fellowship in Minimally Invasive Gynecologic Surgery (FMIGS)- trained faculty and increased surgical training for academic specialists in obstetrics and gynecology occurred in 2020. MEASUREMENTS AND MAIN RESULTS: Patients in the pre-intervention cohort (n=171) were older (median age 45 years vs. 43 years, p=0.003) while patients in the post-intervention cohort (n=234) had a higher burden of comorbidities (26% ASA class III vs. 19%, p=0.03). Uterine weight was not significantly different between cohorts (p=0.328). Between the pre-intervention and post-intervention cohorts, high-volume minimally invasive surgeons increased from 27% (n=4) to 44% (n=7) of those performing hysterectomies within the division and percentage of hysterectomies performed via minimally invasive route increased (63% vs. 82%, p<0.001). In the pre-intervention cohort, Black patients had a lower percentage of hysterectomies performed via minimally invasive route compared to White patients (Black = 56% MIH vs. White = 76% MIH, p=0.014). In the post-intervention cohort, differences by race were no longer significant (Black = 78% MIH vs. White = 87% MIH, p= 0.127). There was a significant increase (22%) in MIH for Black patients between cohorts (p<0.001). After adjusting for age, BMI, ASA class, prior surgery, and uterine weight, disparities by race were no longer present in the post-intervention cohort. Perioperative outcomes including length of stay (p<0.001), infection rates (p=0.002) and blood loss (p=0.01) improved post-intervention. CONCLUSION: Increasing FMIGs-trained gynecologic surgeons and providing more opportunities in robotic/laparoscopic training for academic specialists may improve access to MIH for Black patients and reduce disparities.

Tapping the Brakes on New Parkinson Disease Biological Staging.

This Viewpoint cautions against the premature adoption and implementation of biological definitions for Parkinson disease proposed in February 2024.

Spinal Cord Stimulator Inequities Within the US Military Health System.

OBJECTIVES: Although studies have described inequities in spinal cord stimulation (SCS) receipt, there is a lack of information to inform system-level changes to support health care equity. This study evaluated whether Black patients exhaust more treatment options than do White patients, before receiving SCS. MATERIALS AND METHODS: This retrospective cohort study included claims data of Black and non-Latinx White patients who were active-duty service members or military retirees who received a persistent spinal pain syndrome (PSPS) diagnosis associated with back surgery within the US Military Health System, January 2017 to January 2020 (N = 8753). A generalized linear model examined predictors of SCS receipt within two years of diagnosis, including the interaction between race and number of pain-treatment types received. RESULTS: In the generalized linear model, Black patients (10.3% [8.7%, 12.0%]) were less likely to receive SCS than were White patients (13.6% [12.7%, 14.6%]) The interaction term was significant; White patients who received zero to three different types of treatments were more likely to receive SCS than were Black patients who received zero to three treatments, whereas Black and White patients who received >three treatments had similar likelihoods of receiving a SCS. CONCLUSIONS: In a health care system with intended universal access, White patients diagnosed with PSPS tried fewer treatment types before receiving SCS, whereas the number of treatment types tried was not significantly related to SCS receipt in Black patients. Overall, Black patients received SCS less often than did White patients. Findings indicate the need for structured referral pathways, provider evaluation on equity metrics, and top-down support.

An Eye on the First Surgical Side: Appreciating the Potential Impacts of a Second DBS Lead on Ipsilateral Symptoms.

Clinical Vignette: A 63-year-old man with severe essential tremor underwent staged bilateral ventralis intermedius (Vim) deep brain stimulation (DBS). Left Vim DBS resulted in improved right upper extremity tremor control. Months later, the addition of right Vim DBS to the other brain hemisphere was associated with acute worsening of the right upper extremity tremor. Clinical Dilemma: In staged bilateral Vim DBS, second lead implantation may possibly alter ipsilateral tremor control. While ipsilateral improvement is common, rarely, it can disrupt previously achieved benefit. Clinical Solution: DBS programming, including an increase in left Vim DBS amplitude, re-established and enhanced bilateral tremor control. Gap in Knowledge: The mechanisms underlying changes in ipsilateral tremor control following a second lead implantation are unknown. In this case, worsening and subsequent improvement after optimization highlight the potential impact of DBS implantation on the ipsilateral side. Expert Commentary: After staged bilateral Vim DBS, clinicians should keep an eye on the first or original DBS side and carefully monitor for emergent side effects or worsening in tremor. Ipsilateral effects resulting from DBS implantation present a reprogramming opportunity with a potential to further optimize clinical outcomes. Highlights: This case report highlights the potential for ipsilateral tremor worsening following staged bilateral DBS and provides valuable insights into troubleshooting and reprogramming strategies. The report emphasizes the importance of vigilant monitoring and individualized management in optimizing clinical outcomes for patients undergoing staged bilateral DBS for essential tremor.

Obesity is associated with muscle atrophy in rotator cuff tear.

Objective: The primary goal of this study is to evaluate the relationship between Body Mass Index (BMI) and muscle atrophy in individuals with rotator cuff tears. Methods: This study consists of patients with rotator cuff tears identified by MRI from two independent cohorts, the Rotator Cuff Outcomes Workgroup (ROW) and the Multicenter Orthopaedic Outcomes Network (MOON). Presence of atrophy (yes/no) and severity of atrophy (as an ordinal variable) were assessed on MRI by expert physicians. We used multivariable regression models to evaluate the relationship between BMI and muscle atrophy while adjusting for age and sex in each study, conducted sensitivity analyses for full-thickness tear and combined results using inverse variance-weighted meta-analysis. Results: A total of 539 patients (MOON=395, ROW=144) from the combined cohorts had MRI data available on muscle atrophy. Among these patients, 246 (46%) had atrophy of at least one of the muscles of the rotator cuff and 282 (52%) had full-thickness tears. In meta-analysis across both cohorts, each 5 kg/m2 increase in BMI was associated with a 21% (aOR=1.21, 95% CI=1.02, 1.43) increased odds of having muscle atrophy among individuals with any tear size, and 36% (aOR=1.36, 95% CI=1.01-1.81) increased odds among individuals with full-thickness tear. Conclusions: Higher BMI was associated with significantly higher odds of muscle atrophy in patiens with rotator cuff tears. More study is needed to unders1tand why and how this relationship exists, as well as whether interventions to reduce BMI may help improve outcomes for these patients. Level of Evidence: III.

Discrimination experiences and problematic alcohol and cannabis use in young adulthood.

BACKGROUND AND OBJECTIVES: Limited research has examined how discrimination in young adulthood relates to substance use. We examined how multiple and specific types (e.g., race-based) of experiences of unfair treatment are related to problematic alcohol and cannabis use. METHODS: We analyzed cross-sectional data from a diverse cohort of young adults (mean age 24.7) predominantly residing in southern California (n = 2303) to examine associations of multiple (count) and specific experiences (race-, sexual orientation-, gender-based) of perceived everyday discrimination with self-reported alcohol and cannabis use outcomes (consequences, use disorders, and solitary use). We also tested interactions between the three specific discrimination experiences and sociodemographic characteristics (e.g., race-based discrimination × race/ethnicity). RESULTS: In this diverse sample (e.g., 47% Latinx/o and 22% Asian; 22% sexual/gender diverse; 56% female) of young adults, about 46% reported up to four different discrimination experiences and 27% reported race-, 26% gender-, and 5% sexual orientation-based discrimination. Race- and gender-based discrimination and experiencing more types of discrimination were associated with worse cannabis use outcomes. Race-based discrimination was associated with fewer alcohol consequences and lower Alcohol Use Disorders Identification Test (AUDIT) scores. Associations with sexual orientation-based discrimination and the interactions were not significant. DISCUSSION AND CONCLUSIONS: Findings build on limited research on associations of discrimination with cannabis use in young adults. More work is needed to understand the mechanisms by which discrimination influences drinking behaviors. SCIENTIFIC SIGNIFICANCE: This study advances the field by examining the unique contributions of specific and multiple types of discrimination experiences in young adulthood, a critical developmental period in which substance use peaks.

Long-term NMN treatment increases lifespan and healthspan in mice in a sex dependent manner.

Nicotinamide adenine dinucleotide (NAD) is essential for many enzymatic reactions, including those involved in energy metabolism, DNA repair and the activity of sirtuins, a family of defensive deacylases. During aging, levels of NAD + can decrease by up to 50% in some tissues, the repletion of which provides a range of health benefits in both mice and humans. Whether or not the NAD + precursor nicotinamide mononucleotide (NMN) extends lifespan in mammals is not known. Here we investigate the effect of long-term administration of NMN on the health, cancer burden, frailty and lifespan of male and female mice. Without increasing tumor counts or severity in any tissue, NMN treatment of males and females increased activity, maintained more youthful gene expression patterns, and reduced overall frailty. Reduced frailty with NMN treatment was associated with increases in levels of Anerotruncus colihominis, a gut bacterium associated with lower inflammation in mice and increased longevity in humans. NMN slowed the accumulation of adipose tissue later in life and improved metabolic health in male but not female mice, while in females but not males, NMN increased median lifespan by 8.5%, possible due to sex-specific effects of NMN on NAD + metabolism. Together, these data show that chronic NMN treatment delays frailty, alters the microbiome, improves male metabolic health, and increases female mouse lifespan, without increasing cancer burden. These results highlight the potential of NAD + boosters for treating age-related conditions and the importance of using both sexes for interventional lifespan studies.

The Mammalian KU70 C-terminus SAP Domain Is Required to Repair Exogenous DNA Damage.

The mammalian non-homologous end joining (NHEJ) is required for V(D)J recombination as well as coping with exogenously induced DNA double strand breaks (DSBs). Initiated by the binding of KU70/KU80 (KU) dimer to DNA ends and the subsequent recruitment of the DNA- dependent protein kinase catalytic subunit (DNA-PKcs), NHEJ plays a key role in DNA repair. While there has been significant structural understandings of how KU70 participates in NHEJ, the specific function of its highly conserved C-terminal SAP domain remains elusive. In this study, we developed a novel mouse model by deleting the SAP domain but preserving the KU70 nuclear localization and its dimerization ability with KU80. We found that the KU70 SAP deletion did not affect the V(D)J recombination or animal development but significantly impaired the animals and cells in repairing exogenously induced DSBs. We further showed an inability of KU70-ΔSAP cells to retain the DNA Ligase IV (LIG4) and other NHEJ co-factors on chromatin, and a spreading pattern of DSB marker γH2AX in KU70-ΔSAP cells after DNA damage. Our findings suggest that a specific inhibition of the SAP function may offer an opportunity to modulate cell sensitivity to therapeutic DSB-inducing agents without interfering with the developmental function of KU70. KeyPoints: Generation of a novel transgenic mouse line lacking the C-terminal conserved KU70-SAP domainKU70-SAP defends against exogenous DSBs, but unessential for development and V(D)J recombinationKU70-SAP aids in recruiting and retaining NHEJ components, such as LIG4, to DSB sites.

Discovery of ester-linked ubiquitylation of PARP10 mono-ADP-ribosylation in cells: a dual post-translational modification on Glu/Asp side chains.

The prevailing view on post-translational modifications (PTMs) is that amino acid side chains in proteins are modified with a single PTM at any given time. However, a growing body of work has demonstrated crosstalk between different PTMs, some occurring on the same residue. Such interplay is seen with ADP-ribosylation and ubiquitylation, where specialized E3 ligases ubiquitylate targets for proteasomal degradation in an ADP-ribosylation-dependent manner. More recently, the DELTEX family of E3 ligases was reported to catalyze ubiquitylation of the 3'- hydroxy group of the adenine-proximal ribose of free NAD + and ADP-ribose in vitro , generating a non-canonical ubiquitin ester-linked species. In this report, we show, for the first time, that this dual PTM occurs in cells on mono-ADP-ribosylated (MARylated) PARP10 on Glu/Asp sites to form a MAR ubiquitin ester (MARUbe). We term this process m ono- A DP-ribosyl ub iquit ylation or MARUbylation. Using chemical and enzymatic treatments, including a newly characterized bacterial deubiquitinase with esterase-specific activity, we discovered that PARP10 MARUbylation is extended with K11-linked polyubiquitin chains. Finally, mechanistic studies using proteasomal and ubiquitin-activating enzyme inhibitors demonstrated that PARP10 MARUbylation leads to its proteasomal degradation, providing a functional role for this new PTM in regulating protein turnover.

Enhanced RHO-ROCK signaling is associated with CRELD2 production and fibroblast recruitment in cutaneous squamous cell carcinoma.

A key characteristic of cancer cells is their ability to induce changes in their microenvironment that render it permissive to tumor growth, invasion and metastasis. Indeed, these changes are required for tumor progression. Consequently, the tumor microenvironment is emerging as a key source of new targets against cancer, with novel therapies aimed at reversing tumor-promoting changes, reinstating a tumor-hostile microenvironment and suppressing disease progression. RHO-ROCK signaling, and consequent tension within the cellular actomyosin cytoskeleton, regulates a paracrine signaling cascade that establishes a tumor-promoting microenvironment. Here, we show that consistent with our observations in breast cancer, enhanced ROCK activity and consequent production of CRELD2 is associated with the recruitment and tumor-promoting polarization of cancer-associated fibroblasts in cutaneous squamous cell carcinoma. Our observations provide support for the notion that the role of RHO-ROCK signaling in establishing a tumor-promoting microenvironment may be conserved across patients and potentially also different cancer types.

Identification and characterization of TM4SF1+ tumor self-seeded cells.

Tumor self-seeding is a process whereby circulating tumor cells (CTCs) recolonize the primary tumor, which promotes tumor growth, angiogenesis, and invasion. However, the detailed nature and functions of tumor self-seeded cells (TSCs) have not been well defined due to challenges in tracking and isolating TSCs. Here, we report an accurate animal model using photoconvertible tagging to recapitulate the spontaneous process of tumor self-seeding and identify TSCs as a subpopulation of primary tumor cells with enhanced invasiveness and survival. We demonstrate transmembrane-4-L-six-family-1 (TM4SF1) as a marker of TSCs, which promotes migration, invasion, and anchorage-independent survival in cancer cells. By analyzing single-cell RNA sequencing datasets, we identify a potential TSC population with a metastatic profile in patients with cancer, which is detectable in early-stage disease and expands during cancer progression. In summary, we establish a framework to study TSCs and identify emerging cell targets with diagnostic, prognostic, or therapeutic potential in cancers.