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1.
Clin Interv Aging ; 19: 1509-1517, 2024.
Article in English | MEDLINE | ID: mdl-39253399

ABSTRACT

Purpose: In recent times, growing uncertainty has emerged regarding the effectiveness of standard pressure ulcer (PU) risk assessment tools, which are suspected to be no better than clinical judgment, especially in the frail and comorbid elderly population. This study aimed to identify the primary clinical predictive variables for PU development and severity in hospitalized older adults, utilizing a multidimensional frailty assessment, and compare them with the Braden scale. Patients and methods: The population consisted of 316 patients, admitted to the Geriatric Unit and Transitional Care of San Bartolomeo Hospital in Sarzana (Italy) during the period 21/02/22-01/07/22. The collected information included both anamnestic and laboratory data. A comprehensive geriatric assessment was performed, including also anthropometric and physical performance measurements. Multivariate logistic analysis was used, both in a binary classification test and in the subsequent ordinal classification test of severity levels. The final performance of the model was assessed by ROC curve estimation and AUC comparison with the Braden scale. Results: Within the population, 152 subjects (48%) developed PU at different levels of severity. The results showed that age, Braden scale (subscales of mobility and friction/shear), Barthel scale, Mini Nutritional Assessment, hemoglobin, and albumin are predictors associated with the development of PU (AUC 85%). The result is an improvement over the use of the Braden scale alone (AUC 75%). Regarding the identification of predictive factors for PU severity, 4AT also emerges as potentially relevant. Conclusion: Assessing the subject's nutritional status, physical performance, and functional autonomies enables the effective integration of the Braden scale in identifying patients most susceptible to developing PU. Our findings support the integration of a comprehensive set of methodologically robust frailty determinants into traditional risk assessment tools. This integration reflects the mutual interplay between patients' frailty, skin frailty, and PU development in very old hospitalized patients.


Subject(s)
Frail Elderly , Geriatric Assessment , Hospitalization , Pressure Ulcer , Severity of Illness Index , Humans , Pressure Ulcer/epidemiology , Male , Female , Geriatric Assessment/methods , Retrospective Studies , Aged, 80 and over , Italy , Risk Assessment , Hospitalization/statistics & numerical data , Logistic Models , Risk Factors , ROC Curve , Nutrition Assessment , Multivariate Analysis , Aged
2.
Front Med (Lausanne) ; 11: 1393367, 2024.
Article in English | MEDLINE | ID: mdl-39228804

ABSTRACT

Aging is associated with an increased risk of developing pain, especially in the presence of concurrent chronic clinical conditions. Similarly, multimorbidity can affect the perception and ability of older adults to appropriately respond to and communicate pain, and there is a clinical heterogeneity in the processing of painful sensations in different neurological conditions. The present narrative review is aimed at assessing the prevalent diseases associated with poor communication and pain in older adults, together with the available diagnostic instruments for the clinical assessment of pain in such a vulnerable population. Dementia was the most described pathology identified in the current literature associated with poor communication in older adults affected by pain, along with Parkinson's disease and stroke. Notably, a common pattern of pain behaviors in these neurological disorders also emerged, indicating potential similarities in the clinical presentation and appropriate diagnostic workout. At the same time, there are many differences in the way patients express their pain according to their main neurological pathology. In addition to this, although a plethora of observation-based tools for pain in patients with dementia have been developed, there is no gold standard, and the clinical utility of such measurements is still largely unaddressed. Meanwhile, there is substantially no standardized observation-based tool for pain in non-communicative patients with Parkinson's disease, and only a few for stroke. Overall, the present narrative review provides an update on the prevalent diseases beyond dementia associated with a communicative disability and a painful condition in older adults.

3.
Intern Emerg Med ; 2024 Aug 02.
Article in English | MEDLINE | ID: mdl-39095675

ABSTRACT

The raising number of older patients who are diagnosed with breast cancer represents a significant medical and societal challenge. Aromatase inhibitors (AI), which are commonly utilized to treat this condition in these patients have significant adverse events on bone and muscle health. Falling estrogen production leads to an increase in RANKL secretion by osteoblasts with accelerated bone remodeling due to osteoclast activity. Furthermore, estrogen deficiency reduces skeletal muscle strength and mass. The humanized monoclonal antibody, denosumab, neutralizes RANKL, thereby inhibiting osteoclast formation, function and survival and ultimately exerting powerful anti-resorptive effects.. In this study, we report on the efficacy of denosumab in mitigating aromatase inhibitor-induced bone loss (AIBL) and sarcopenia in older women with breast cancer. From January 2022 to January 2023, we enrolled 30 patients (female sex, ≥ 65 years) diagnosed with non-metastatic breast cancer undergoing adjuvant endocrine therapy; patients received, as per clinical practice, primary bone prophylaxis with denosumab (60 mg via subcutaneous injection every 6 months) according to oncologic guidelines. This group was matched with 30 patients with non-metastatic breast cancer, who were treated with biphosphonates (BF) therapy (oral alendronate 70 mg/week). For each patient bone mineral density (BMD) and bone quality in terms of trabecular bone score (TBS) in addition to body composition and Relative Skeletal Muscle Index (RSMI) was assessed by bone densitometry at baseline and after one year of treatment. Significant improvements in TBS at the lumbar spine, RSMI and whole-body composition (arms, legs, and trunk) were observed in the denosumab group compared with the BF group. These findings underscore the role of denosumab as an effective strategy in managing AIBL and osteosarcopenia in older women with breast cancer and undergoing adjuvant endocrine therapy, which is crucial for improving quality of life, preventing functional decline, and optimizing treatment outcomes.

4.
Aging Cell ; : e14289, 2024 Aug 05.
Article in English | MEDLINE | ID: mdl-39102875

ABSTRACT

Neuronal senescence is a major risk factor for the development of many neurodegenerative disorders. The mechanisms that drive neurons to senescence remain largely elusive; however, dysregulated mitochondrial physiology seems to play a pivotal role in this process. Consequently, strategies aimed to preserve mitochondrial function may hold promise in mitigating neuronal senescence. For example, dietary restriction has shown to reduce senescence, via a mechanism that still remains far from being totally understood, but that could be at least partially mediated by mitochondria. Here, we address the role of mitochondrial inorganic polyphosphate (polyP) in the intersection between neuronal senescence and dietary restriction. PolyP is highly present in mammalian mitochondria; and its regulatory role in mammalian bioenergetics has already been described by us and others. Our data demonstrate that depletion of mitochondrial polyP exacerbates neuronal senescence, independently of whether dietary restriction is present. However, dietary restriction in polyP-depleted cells activates AMPK, and it restores some components of mitochondrial physiology, even if this is not sufficient to revert increased senescence. The effects of dietary restriction on polyP levels and AMPK activation are conserved in differentiated SH-SY5Y cells and brain tissue of male mice. Our results identify polyP as an important component in mitochondrial physiology at the intersection of dietary restriction and senescence, and they highlight the importance of the organelle in this intersection.

5.
Front Med (Lausanne) ; 11: 1439353, 2024.
Article in English | MEDLINE | ID: mdl-39165376

ABSTRACT

Background: Sarcopenia, characterized by muscle mass, strength, and performance decline, significantly impacts outcomes in older adults. This study aims to assess the predictive value of calf circumference (CC), in conjunction with SARC-F and hand grip, concerning in-hospital complications and post-discharge mortality among hospitalized frail older adults. Methods: A cohort of 158 hospitalized patients aged over 65 years underwent Comprehensive Geriatric Assessment and sarcopenia screening, including CC measurement. Multivariable regression analyses, adjusted for confounders, were conducted to assess predictive associations. Results: The study cohort, comprising 53% males with a median age of 86 years, exhibited significant sarcopenia prevalence based on SARC-F (85% indicating sarcopenia), hand grip strength (probable sarcopenia in 77% of males and 72% of females), and CC (sarcopenia in 83%). Multivariate analysis, adjusting for age, sex, Clinical Frailty Scale (CFS), and Mini Nutritional Assessment-Short Form (MNA-SF), demonstrated associations of CC and SARC-F with in-hospital complications, while CC also showed a significant association with reduced risks of in-hospital mortality (OR 0.441, 95% CI 0.257 to 0.754, p = 0.003) and 90-day mortality (OR 0.714, 95% CI 0.516 to 0.988, p = 0.043). Conclusion: This study provides insights into the predictive accuracy of sarcopenia screening tools on mortality in real-world hospitalized older adults with frailty. Notably, CC emerges as a robust predictor of mortality outcomes. Further research is warranted to validate and elucidate the respective contributions of CC and frailty to mortality in vulnerable populations.

6.
Nutrients ; 16(14)2024 Jul 13.
Article in English | MEDLINE | ID: mdl-39064705

ABSTRACT

There is currently a growing interest in diets and physical activity patterns that may be beneficial in preventing and treating breast cancer (BC). Mounting evidence indicates that indeed, the so-called Mediterranean diet (MedDiet) and regular physical activity likely both help reduce the risk of developing BC. For those who have already received a BC diagnosis, these interventions may decrease the risk of tumor recurrence after treatment and improve quality of life. Studies also show the potential of other dietary interventions, including fasting or modified fasting, calorie restriction, ketogenic diets, and vegan or plant-based diets, to enhance the efficacy of BC therapies. In this review article, we discuss the biological rationale for utilizing these dietary interventions and physical activity in BC prevention and treatment. We highlight published and ongoing clinical studies that have applied these lifestyle interventions to BC patients. This review offers valuable insights into the potential application of these dietary interventions and physical activity as complimentary therapies in BC management.


Subject(s)
Breast Neoplasms , Diet, Ketogenic , Diet, Mediterranean , Exercise , Humans , Breast Neoplasms/prevention & control , Breast Neoplasms/therapy , Female , Caloric Restriction , Quality of Life , Diet
7.
Int J Mol Sci ; 25(4)2024 Feb 08.
Article in English | MEDLINE | ID: mdl-38396769

ABSTRACT

The addiction of tumors to elevated nicotinamide adenine dinucleotide (NAD+) levels is a hallmark of cancer metabolism. Obstructing NAD+ biosynthesis in tumors is a new and promising antineoplastic strategy. Inhibitors developed against nicotinamide phosphoribosyltransferase (NAMPT), the main enzyme in NAD+ production from nicotinamide, elicited robust anticancer activity in preclinical models but not in patients, implying that other NAD+-biosynthetic pathways are also active in tumors and provide sufficient NAD+ amounts despite NAMPT obstruction. Recent studies show that NAD+ biosynthesis through the so-called "Preiss-Handler (PH) pathway", which utilizes nicotinate as a precursor, actively operates in many tumors and accounts for tumor resistance to NAMPT inhibitors. The PH pathway consists of three sequential enzymatic steps that are catalyzed by nicotinate phosphoribosyltransferase (NAPRT), nicotinamide mononucleotide adenylyltransferases (NMNATs), and NAD+ synthetase (NADSYN1). Here, we focus on these enzymes as emerging targets in cancer drug discovery, summarizing their reported inhibitors and describing their current or potential exploitation as anticancer agents. Finally, we also focus on additional NAD+-producing enzymes acting in alternative NAD+-producing routes that could also be relevant in tumors and thus become viable targets for drug discovery.


Subject(s)
Antineoplastic Agents , Neoplasms , Niacin , Humans , NAD/metabolism , Nicotinamide Phosphoribosyltransferase/metabolism , Neoplasms/drug therapy , Niacinamide/pharmacology , Niacinamide/therapeutic use , Niacinamide/metabolism , Cytokines/metabolism , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use
8.
Med Chem ; 20(7): 694-708, 2024.
Article in English | MEDLINE | ID: mdl-38333979

ABSTRACT

BACKGROUND: During the past two decades, many nicotinamide phosphoribosyltransferase (NAMPT) inhibitors were prepared and tested because this enzyme is overexpressed in pancreatic cancer. Although FK866 is a well-known, strong NAMPT inhibitor, it suffers severe drawbacks. OBJECTIVE: Our work aimed to synthesize efficient NAMPT inhibitors featuring better pharmacokinetic properties than the pyridine-containing FK866. To this aim, the new anticancer agents were based on benzene, pyridazine, or benzothiazole moieties as a cap group instead of the pyridine unit found in FK866 and other NAMPT inhibitors. METHODS: The new compounds, prepared exploiting standard heterocycle chemistry and coupling reactions (e.g., formation of amides, ureas, and cyanoguanidines, copper-mediated azide-alkyne cycloaddition), have been fully characterized using NMR and HRMS analyses. Their activity has been evaluated using cytotoxicity and intracellular NAD depletion assays in the human pancreatic cancer cell line MiaPaCa-2. RESULTS: Among the 14 products obtained, compound 28, bearing a pyridazine unit as the cap group and a thiophene moiety as the tail group, showed 6.7 nanomolar inhibition activity in the intracellular NAD depletion assay and 43 nanomolar inhibition in the MiaPaCa-2 cells cytotoxicity assay, comparable to that observed for FK866. CONCLUSION: The positive results observed for some newly synthesized molecules, particularly those carrying a thiophene unit as a tail group, indicate that they could act as in vivo anti-pancreatic cancer agents.


Subject(s)
Acrylamides , Antineoplastic Agents , Enzyme Inhibitors , Nicotinamide Phosphoribosyltransferase , Pancreatic Neoplasms , Piperidines , Nicotinamide Phosphoribosyltransferase/antagonists & inhibitors , Nicotinamide Phosphoribosyltransferase/metabolism , Humans , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Antineoplastic Agents/chemical synthesis , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/pathology , Pancreatic Neoplasms/metabolism , Piperidines/pharmacology , Piperidines/chemistry , Piperidines/chemical synthesis , Cell Line, Tumor , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/chemical synthesis , Acrylamides/pharmacology , Acrylamides/chemical synthesis , Acrylamides/chemistry , Structure-Activity Relationship , Drug Screening Assays, Antitumor , Molecular Structure , Cell Proliferation/drug effects
9.
Nutrients ; 15(24)2023 Dec 14.
Article in English | MEDLINE | ID: mdl-38140367

ABSTRACT

Fasting is a nutritional practice involving complete food restriction for a varying length of time [...].


Subject(s)
Cognitive Dysfunction , Fasting , Humans , Food Deprivation , Cognitive Dysfunction/etiology , Food
10.
Front Immunol ; 14: 1268756, 2023.
Article in English | MEDLINE | ID: mdl-37915565

ABSTRACT

Nicotinamide phosphoribosyltransferase (NAMPT) plays a central role in mammalian cell metabolism by contributing to nicotinamide adenine dinucleotide biosynthesis. However, NAMPT activity is not limited to the intracellular compartment, as once secreted, the protein accomplishes diverse functions in the extracellular space. Extracellular NAMPT (eNAMPT, also called visfatin or pre-B-cell colony enhancing factor) has been shown to possess adipocytokine, pro-inflammatory, and pro-angiogenic activities. Numerous studies have reported the association between elevated levels of circulating eNAMPT and various inflammatory and metabolic disorders such as obesity, diabetes, atherosclerosis, arthritis, inflammatory bowel disease, lung injury and cancer. In this review, we summarize the current state of knowledge on eNAMPT biology, proposed roles in disease pathogenesis, and its potential as a disease biomarker. We also briefly discuss the emerging therapeutic approaches for eNAMPT inhibition.


Subject(s)
Diabetes Mellitus , Neoplasms , Animals , Humans , Nicotinamide Phosphoribosyltransferase/metabolism , Extracellular Space/metabolism , Biomarkers , Mammals/metabolism
11.
Nat Commun ; 14(1): 6951, 2023 10 31.
Article in English | MEDLINE | ID: mdl-37907500

ABSTRACT

Identifying oncological applications for drugs that are already approved for other medical indications is considered a possible solution for the increasing costs of cancer treatment. Under the hypothesis that nutritional stress through fasting might enhance the antitumour properties of at least some non-oncological agents, by screening drug libraries, we find that cholesterol biosynthesis inhibitors (CBIs), including simvastatin, have increased activity against cancers of different histology under fasting conditions. We show fasting's ability to increase CBIs' antitumour effects to depend on the reduction in circulating insulin, insulin-like growth factor-1 and leptin, which blunts the expression of enzymes from the cholesterol biosynthesis pathway and enhances cholesterol efflux from cancer cells. Ultimately, low cholesterol levels through combined fasting and CBIs reduce AKT and STAT3 activity, oxidative phosphorylation and energy stores in the tumour. Our results support further studies of CBIs in combination with fasting-based dietary regimens in cancer treatment and highlight the value of fasting for drug repurposing in oncology.


Subject(s)
Fasting , Simvastatin , Simvastatin/pharmacology , Simvastatin/therapeutic use , Diet , Insulin , Cholesterol
13.
Diagnostics (Basel) ; 13(18)2023 Sep 11.
Article in English | MEDLINE | ID: mdl-37761272

ABSTRACT

Optimizing the functional status of patients of any age is a major global public health goal. Rehabilitation is a process in which a person with disabilities is accompanied to achieve the best possible physical, functional, social, intellectual, and relational outcomes. The Intermediate Care Unit within the O.U. of Geriatrics and Gerontology of the San Martino Hospital in Genoa is focused on the treatment and motor reactivation of patients with geriatric pathologies. The objective of this study was to identify which factor, among the characteristics related to the patient and those identified by the geriatric evaluation, had the greatest impact on rehabilitation outcomes. Our findings revealed significant correlations between the Barthel Index delta, the 4AT Screening Test, and the number of drugs taken. This association highlights the potential benefits of medication management in enhancing the overall well-being and functional abilities of frail older adults, despite the literature suggesting that polypharmacotherapy is associated with a reduction in functional status and an increase in mortality. These findings underscore the significance of a multidimensional geriatric assessment. Refining and optimising these multidisciplinary approaches is the objective of a more effective geriatric rehabilitation strategy.

14.
J Chemother ; 35(8): 730-736, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37608747

ABSTRACT

Clinical trials demonstrated that SARS-CoV-2 vaccines reduce COVID-19-related mortality and morbidity. We describe the effect of vaccination on COVID-19-patients admitted at our hospital. Retrospective, single-center study conducted in Genoa, Italy, including patients ≥18years hospitalized for COVID-19 from May to December 2021. Demographical and clinical data were collected, vaccinated (group-A) and not-vaccinated (group-B) patients were compared. Impact of vaccination on mortality, ICU admission, and oxygen need was studied using Cox proportional hazards and logistic regression models after adjusting for propensity scores. Overall, 395 patients SARS-CoV-2 infected were included, of which 150 (38%) were vaccinated and 245 (62%) were not vaccinated. Patients in group-A were older, more disable, and with higher morbidity. Overall, 64 patients (16%) died within 30 days from admission, 34 in Group A (23%), and 30 in group B (12%). However, no statistically significant differences were observed (group-A versus group-B: HR 0.83, 95% CI 0.49-1.40, p = 0.483). On the other hand, vaccination was protective in terms of ICU admission (OR = 0.23, p = 0.046) and oxygen need (OR = 0.33, p = 0.008). Our study confirms that SARS-CoV-2 vaccination reduces morbidity among patients hospitalized for COVID-19. The still high mortality in our cohort of vaccinated individuals could be partially due to vulnerable conditions of our patients.


Subject(s)
COVID-19 , Humans , COVID-19/prevention & control , COVID-19 Vaccines/therapeutic use , SARS-CoV-2 , Retrospective Studies , Hospitals , Vaccination , Italy/epidemiology , Oxygen
15.
Front Med (Lausanne) ; 10: 1200007, 2023.
Article in English | MEDLINE | ID: mdl-37554502

ABSTRACT

It's still undetermined whether ultra-old persons, aged >90 years, are able to tolerate hip fracture surgical stress while maintaining their functional reserve, and even fewer studies have investigated the role of frailty on the risk of mortality, disability, or morbidity in the ultra-old. This is a prospective study performed at the Orthogeriatrics Ward of the IRCCS Policlinico San Martino (Genoa, Italy) that consecutively enrolled 205 older adult patients with hip fractures due to low-energy trauma. Namely, 85 patients were categorized as ultra-old, and 120 patients (64-89 years) were the younger control group. Demographic data, perioperative data, and rehabilitation data were collected. Here we estimated the overall survival and related predictive variables in hospitalized ultra-old hip fracture patients based on a methodologically robust frailty stratification (Rockwood 40-item tool). The median OS for the ultra-old was 18.7 months, which also showed a doubled 1-year mortality risk. Our findings assessed that frailty in the presence of malnutrition, delayed verticalization, and post-operative respiratory complications was associated with a two-fold increase in the risk of long-term mortality, irrespective of advanced chronological age in the ultra-old. Although the higher mortality rate in these patients may be related to a priori lower life expectancy, chronological age alone is an insufficient prognostic determinant for unfavorable outcomes. Our multicomponent prognostic score can be used in combination to stratify frailty in the ultra-old for timely screening and to deliver goals of care discussions prior to surgery, potentially targeting new orthogeriatric pathways for the improvement of appropriateness and treatment intensity.

16.
Biomed Pharmacother ; 166: 115326, 2023 10.
Article in English | MEDLINE | ID: mdl-37611438

ABSTRACT

Sirtuin 6 (SIRT6) has a critical role in cutaneous Squamous Cell Carcinoma (cSCC): SIRT6 silencing in skin SCC cells has pro-differentiating effects and SIRT6 deletion abrogated DMBA-TPA-induced skin tumorigenesis in mice. On the other hand, SIRT6 acts as tumor suppressor in SCC by enhancing glycolysis in tumor propagating cells. Herein, pharmacological modulation of SIRT6 deacetylase activity was investigated in cSCC, with S6 (inhibitor) or MDL-800 (activator). In cSCC cells, S6 recreated the pro-differentiating effects of SIRT6 silencing, as the levels of Keratin 1, Keratin 10 and Loricrin were upregulated compared to controls. Next, the effects of SIRT6 pharmacological modulation were evaluated in a DMBA-TPA-induced skin cancer mouse model. Mice treated with the inhibitor S6 in a preventive approach, i.e. at the beginning of the promotion stage, presented reduced number and size of papillomas, compared to the controls. The epidermal hyperproliferation marker Keratin 6 and the cSCC marker Keratin 8 were less abundant when SIRT6 was inhibited. In S6-treated lesions, the Epithelial-Mesenchymal Transition (EMT) markers Zeb1 and Vimentin were less expressed compared to untreated lesions. In a therapeutic approach, i.e. treatment starting after papilloma appearance, the S6 group presented reduced papillomas (number and size), whereas MDL-800-treated mice displayed an opposite trend. In S6-treated lesions, Keratin 6 and Keratin 8 were less expressed, EMT was less advanced, with a higher E-cadherin/Vimentin ratio, indicating a delayed carcinogenesis when SIRT6 was inhibited. Our results confirm that SIRT6 plays a role in skin carcinogenesis and suggest SIRT6 pharmacological inhibition as a promising strategy in cSCC.


Subject(s)
Carcinoma, Squamous Cell , Papilloma , Sirtuins , Skin Neoplasms , Animals , Mice , Skin Neoplasms/drug therapy , Carcinoma, Squamous Cell/drug therapy , Keratin-8 , Vimentin , Keratin-6 , Carcinogenesis
18.
Pharmaceutics ; 15(5)2023 May 11.
Article in English | MEDLINE | ID: mdl-37242714

ABSTRACT

The nicotinamide phosphoribosyltransferase (NAMPT) is considered a very promising therapeutic target because it is overexpressed in pancreatic cancer. Although many inhibitors have been prepared and tested, clinical trials have shown that NAMPT inhibition may result in severe haematological toxicity. Therefore, the development of conceptually new inhibitors is an important and challenging task. We synthesized ten ß-d-iminoribofuranosides bearing various heterocycle-based chains carbon-linked to the anomeric position starting from non-carbohydrate derivatives. They were then submitted to NAMPT inhibition assays, as well as to pancreatic tumor cells viability and intracellular NAD+ depletion evaluation. The biological activity of the compounds was compared to that of the corresponding analogues lacking the carbohydrate unit to assess, for the first time, the contribution of the iminosugar moiety to the properties of these potential antitumor agents.

19.
Neoplasia ; 41: 100903, 2023 07.
Article in English | MEDLINE | ID: mdl-37148658

ABSTRACT

Nicotinamide phosphoribosyltransferase (NAMPT) is a key metabolic enzyme in NAD+ synthesis pathways and is found upregulated in several tumors, depicting NAD(H) lowering agents, like the NAMPT inhibitor FK866, as an appealing approach for anticancer therapy. Like other small molecules, FK866 triggers chemoresistance, observed in several cancer cellular models, which can prevent its clinical application. The molecular mechanisms sustaining the acquired of resistance to FK866 were studied in a model of triple negative breast cancer (MDA-MB-231 parental - PAR), exposed to increasing concentrations of the small molecule (MDA-MB-231 resistant - RES). RES cells are not sensitive to verapamil or cyclosporin A, excluding a potential role of increased efflux pumps activity as a mechanism of resistance. Similarly, the silencing of the enzyme Nicotinamide Riboside Kinase 1 (NMRK1) in RES cells does not increase FK866 toxicity, excluding this pathway as a compensatory mechanism of NAD+ production. Instead, Seahorse metabolic analysis revealed an increased mitochondrial spare respiratory capacity in RES cells. These cells presented a higher mitochondrial mass compared to the FK866-sensitive counterparts, as well as an increased consumption of pyruvate and succinate for energy production. Interestingly, co-treatment of PAR cells with FK866 and the mitochondrial pyruvate carrier (MPC) inhibitors UK5099 or rosiglitazone, as well as with the transient silencing of MPC2 but not of MPC1, induces a FK866-resistant phenotype. Taken together, these results unravel novel mechanisms of cell plasticity to counteract FK866 toxicity, that, besides the previously described LDHA dependency, rely on mitochondrial rewiring at functional and energetic levels.


Subject(s)
NAD , Triple Negative Breast Neoplasms , Humans , NAD/metabolism , Triple Negative Breast Neoplasms/drug therapy , Triple Negative Breast Neoplasms/genetics , Cytokines/metabolism , Nicotinamide Phosphoribosyltransferase/genetics , Nicotinamide Phosphoribosyltransferase/metabolism , Mitochondria/metabolism , Cell Line, Tumor , Phosphotransferases (Alcohol Group Acceptor)
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