Cellular Distribution and Ultrastructural Changes in HaCaT Cells, Induced by Podophyllotoxin and Its Novel Fluorescent Derivative, Supported by the Molecular Docking Studies.

Podophyllotoxin (PPT) is an active pharmaceutical ingredient (API) with established antitumor potential. However, due to its systemic toxicity, its use is restricted to topical treatment of anogenital warts. Less toxic PPT derivatives (e.g., etoposide and teniposide) are used intravenously as anticancer agents. PPT has been exploited as a scaffold of new potential therapeutic agents; however, fewer studies have been conducted on the parent molecule than on its derivatives. We have undertaken a study of ultrastructural changes induced by PPT on HaCaT keratinocytes. We have also tracked the intracellular localization of PPT using its fluorescent derivative (PPT-FL). Moreover, we performed molecular docking of both PPT and PPT-FL to compare their affinity to various binding sites of tubulin. Using the Presto blue viability assay, we established working concentrations of PPT in HaCaT cells. Subsequently, we have used selected concentrations to determine PPT effects at the ultrastructural level. Dynamics of PPT distribution by confocal microscopy was performed using PPT-FL. Molecular docking calculations were conducted using Glide. PPT induces a time-dependent cytotoxic effect on HaCaT cells. Within 24 h, we observed the elongation of cytoplasmic processes, formation of cytoplasmic vacuoles, progressive ER stress, and shortening of the mitochondrial long axis. After 48 h, we noticed disintegration of the cell membrane, progressive vacuolization, apoptotic/necrotic vesicles, and a change in the cell nucleus's appearance. PPT-FL was detected within HaCaT cells after ~10 min of incubation and remained within cells in the following measurements. Molecular docking confirmed the formation of a stable complex between tubulin and both PPT and PPT-FL. However, it was formed at different binding sites. PPT is highly toxic to normal human keratinocytes, even at low concentrations. It promptly enters the cells, probably via endocytosis. At lower concentrations, PPT causes disruptions in both ER and mitochondria, while at higher concentrations, it leads to massive vacuolization with subsequent cell death. The novel derivative of PPT, PPT-FL, forms a stable complex with tubulin, and therefore, it is a useful tracker of intracellular PPT binding and trafficking.

Homotypic Entosis as a Potential Novel Diagnostic Marker in Breast Cancer.

Homotypic entotic figures, which are a form of "cell-in-cell" structures, are considered a potential novel independent prognostic marker in various cancers. Nevertheless, the knowledge concerning the biological role of this phenomenon is still unclear. Since breast cancer cells are remarkably entosis-competent, we aimed to investigate and compare the frequency of entoses in a primary breast tumor and in its lymph node metastasis. Moreover, as there are limited data on defined molecular markers of entosis, we investigated entosis in correlation with classical breast cancer biomarkers used in routine pathomorphological diagnostics (HER2, ER, PR, and Ki67). In the study, a cohort of entosis-positive breast cancer samples paired into primary lesions and lymph node metastases was used. The inclusion criteria were a diagnosis of NOS cancer, lymph node metastases, the presence of entotic figures in the primary lesion, and/or lymph node metastases. In a selected, double-negative, HER2-positive NOS breast cancer case, entoses were characterized by a correlation between an epithelial-mesenchymal transition and proliferation markers. We observed that in the investigated cohort entotic figures were positively correlated with Ki67 and HER2, but not with ER or PR markers. Moreover, for the first time, we identified Ki67-positive mitotic inner entotic cells in clinical carcinoma samples. Our study performed on primary and secondary breast cancer specimens indicated that entotic figures, when examined by routine HE histological staining, present potential diagnostic value, since they correlate with two classical prognostic factors of breast cancer.

Application of PCSK9 Inhibitors in Practice.

PCSK9i (protein convertase subtilisin/kexin type 9 inhibitors) are set to revolutionize the treatment of hypercholesterolemia in the management of atherosclerotic risk, but numerous reports have detailed unprecedented barriers to access for these drugs. To overcome these challenges, our group created a model to facilitate provision of this new therapy for patients who qualify according to Food and Drug Administration criteria. This report details the real-world follow-up experience of PCSK9i use in a large patient cohort structured to ensure rigor in data collection, analysis, and interpretation. The 271 patients approved and actively followed in our PCSK9i clinic between July 2015 and August 2018 represent a 97% approval rate from insurance, with 28% of prescriptions requiring at least one appeal. Over 50% of patients were statin intolerant. On average, there was a median lapse of 15 days between initial visit and insurance approval. PCSK9i therapy was affordable for most patients, with an average monthly out-of-pocket expense of $58.05 (median $0). Only 2.3% of patients were unable to initiate or continue therapy because of cost. Reductions from baseline in LDL (low-density lipoprotein) cholesterol and Lp(a) (lipoprotein [a])were comparable to published reports with median reductions of 60% and 23% at 1 year, respectively. PCSK9i therapy was well-tolerated overall, though 9% of patients reported adverse events, and 5% of patients discontinued due mostly to musculoskeletal and flu-like symptoms. Our practice model demonstrates that PCSK9i therapy can be accessed easily and affordably for the majority of eligible patients, resulting in dramatic improvement in lipid profile results. Moreover, our registry data suggest that results from the prospective clinical trials of PCSK9i on LDL and Lp(a) reduction and on tolerability are applicable to a real-world cohort.

Mechanisms and Evidence for Heart Failure Benefits from SGLT2 Inhibitors.

PURPOSE OF REVIEW: To review the clinical trial data and underlying mechanistic principles in support of the robust cardiovascular (CV) benefits, in particular, heart failure (HF) outcomes association with sodium-glucose co-transporter-2 (SGLT2) inhibitors. RECENT FINDINGS: Several large CV outcome trials in patients with type 2 diabetes mellitus (T2DM) and with either established atherosclerotic CV disease (ASCVD) or at high risk for ASCVD reveal that SGLT2 inhibitors cause reductions in CV and HF endpoints. The reduction in ASCVD appears to be confined to those with established ASCVD on the order of ≈ 14%, as does the mortality benefit-all-cause and CV-related. However, hospitalization for HF are reduced by ≈ 33% and occur regardless of baseline patient characteristics. The unprecedented HF outcomes are theorized to occur via several possible mechanisms and include optimization of conventional ASCVD risk factors, improvement in hemodynamics, prevention of cardiac and renal remodeling, inhibition of hormone dysregulation, use of more efficient metabolic substrates, ion channel inhibition, anti-inflammatory effects, and anti-oxidant effects. Recent evidence has unveiled the irrefutable data that SGLT2 inhibitors reduce CV events in patients with T2DM, with a profound effect on reductions in hospitalization for HF. Though several mechanisms conveying this benefit are suggested, most are based in limited data requiring further validation. Nonetheless, the arrival of SGLT2 inhibitors has ushered in a new era of CV risk reductions therapies.

Modulation of adipocyte differentiation by omega-3 polyunsaturated fatty acids involves the ubiquitin-proteasome system.

We have evaluated the effects of three different omega-3 polyunsaturated fatty acids (ω-3 PUFAs) ­ docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA) on fat accumulation and expression of adipogenic and inflammatory markers using both 3T3-L1 pre-adipocytes and differentiated 3T3-L1 adipocytes. Our results indicate that ω-3 PUFAs induce the degradation of fatty acid synthase through the ubiquitin-proteasome system, which is likely to have beneficial metabolic effect on adipose cells. Omega-3 PUFAs also increase overall levels of polyubiquitinated proteins, at least in part through decreasing the expression of proteasome subunits. Moreover, adipocytes are resistant to proteasome inhibition, which induces adipophilin while decreasing perilipin expression. On the other hand, ω-3 PUFAs decrease expression of SREBP1 while inducing expression of adipophilin and GLUT4. Moreover, all three ω-3 PUFAs appear to induce tumour necrosis factor-α without affecting NFκB levels. All three ω-3 PUFAs appear to have overall similar effects. Further research is needed to elucidate their mechanism of action.

LOGAN-CV: A Prospective Study of a Multifaceted Intervention Targeting United States Clinicians to Improve Guideline-Based Management of Lipid-Lowering Therapy.

INTRODUCTION: The 2018 American Heart Association (AHA)/American College of Cardiology (ACC)/Multisociety blood cholesterol guidelines recommend clinicians consider adding non-statin therapy for patients with very high-risk (VHR) atherosclerotic cardiovascular disease (ASCVD) and low-density lipoprotein cholesterol (LDL-C) ≥ 70 mg/dl while receiving maximally tolerated statins. However, according to a recent study, only 17.1% of patients with established ASCVD received appropriate lipid-lowering therapy (LLT) intensification. Here, we describe the design of a prospective, 12-month study (LOGAN-CV) evaluating a multifaceted site-level intervention to enhance clinicians' adherence to guidelines to improve LDL-C levels for patients with VHR ASCVD. METHODS: Clinicians from up to ten research sites are eligible if they care for adult patients with ASCVD. Interventions include educational modules, a cloud-based performance platform providing clinicians a tailored summary of their LDL-C management performance, newsletters, periodic peer-to-peer calls, and pre- and post-intervention surveys evaluating knowledge, attitudes, and beliefs around LDL-C management, with additional interventions for clinicians demonstrating a lower readiness to make treatment decisions based on guideline recommendations. Patients with VHR ASCVD, defined as having recent myocardial infarction and LDL-C ≥ 70 mg/dl despite statin treatment, will be included in the study. Patient data will be collected from electronic medical records from baseline (clinician enrollment) through the 12-month intervention. The study started in October 2022, with anticipated completion in March 2024. PLANNED OUTCOMES: The change in proportion of patients with LDL-C < 70 mg/dl achieved at any time during the 12-month intervention (primary); LLT intensification, changes in guideline-aligned LDL-C testing and LLT titration over 12 months, and change in overall clinicians' knowledge, attitudes, and beliefs are key outcomes of interest. The LOGAN-CV study addresses a critical unmet need in LDL-C control in patients with VHR ASCVD and evaluates the effect of a multifaceted intervention targeting clinicians to improve their adherence to guidelines and consequently improve clinical outcomes for patients.

Cardiotoxicity of the anticancer therapeutic agent bortezomib.

Recent case reports provided alarming signals that treatment with bortezomib might be associated with cardiac events. In all reported cases, patients experiencing cardiac problems were previously or concomitantly treated with other chemotherapeutics including cardiotoxic anthracyclines. Therefore, it is difficult to distinguish which components of the therapeutic regimens contribute to cardiotoxicity. Here, we addressed the influence of bortezomib on cardiac function in rats that were not treated with other drugs. Rats were treated with bortezomib at a dose of 0.2 mg/kg thrice weekly. Echocardiography, histopathology, and electron microscopy were used to evaluate cardiac function and structural changes. Respiration of the rat heart mitochondria was measured polarographically. Cell culture experiments were used to determine the influence of bortezomib on cardiomyocyte survival, contractility, Ca(2+) fluxes, induction of endoplasmic reticulum stress, and autophagy. Our findings indicate that bortezomib treatment leads to left ventricular contractile dysfunction manifested by a significant drop in left ventricle ejection fraction. Dramatic ultrastructural abnormalities of cardiomyocytes, especially within mitochondria, were accompanied by decreased ATP synthesis and decreased cardiomyocyte contractility. Monitoring of cardiac function in bortezomib-treated patients should be implemented to evaluate how frequently cardiotoxicity develops especially in patients with pre-existing cardiac conditions, as well as when using additional cardiotoxic drugs.

Classification of Cell-in-Cell Structures: Different Phenomena with Similar Appearance.

A phenomenon known for over 100 years named "cell-in-cell" (CIC) is now undergoing its renaissance, mostly due to modern cell visualization techniques. It is no longer an esoteric process studied by a few cell biologists, as there is increasing evidence that CICs may have prognostic and diagnostic value for cancer patients. There are many unresolved questions stemming from the difficulties in studying CICs and the limitations of current molecular techniques. CIC formation involves a dynamic interaction between an outer or engulfing cell and an inner or engulfed cell, which can be of the same (homotypic) or different kind (heterotypic). Either one of those cells appears to be able to initiate this process, which involves signaling through cell-cell adhesion, followed by cytoskeleton activation, leading to the deformation of the cellular membrane and movements of both cells that subsequently result in CICs. This review focuses on the distinction of five known forms of CIC (cell cannibalism, phagoptosis, enclysis, entosis, and emperipolesis), their unique features, characteristics, and underlying molecular mechanisms.

Novel podophyllotoxin and benzothiazole derivative induces transitional morphological and functional changes in HaCaT cells.

Podophyllotoxin (PPT) is an antimitotic drug used topically in the treatment of anogenital warts. Due to its toxicity it cannot be administered systemically as an anticancer agent. However, modified PPT derivatives such as etoposide and teniposide are used clinically as systemic agents. Thus, we invented novel PPT derivative KL3 that was synthesized by photocyclization. Earlier we have shown that KL3 has an anticancer effect in various cell lines. Here we compared the toxicity of KL3 vs PPT on non-cancerous normal human keratinocytes (HaCaT) and peripheral blood mononuclear cells (PBMC) showing that KL3 is less toxic than PPT to non-cancerous cells. At concentrations that neither induced cell death, nor affected cell cycle, KL3 in HaCaT cells evoked transient ultrastructural features of ER stress, swelling of mitochondria and elongation of cytoplasmic processes. Those changes partially reversed with prolonged incubation while features of autophagy were induced. PPT in equivalent concentrations induced HaCaT cell death by cell cycle arrest, intrinsic apoptosis and finally disintegration of cell membranes followed by secondary necrosis. In conclusion, we show that the KL3 derivative of PPT in contrast to PPT allows repair of normal keratinocytes and triggers mechanisms that restore non-tumor cell homeostasis.

Hepatic Sensing Loop Regulates PCSK9 Secretion in Response to Inhibitory Antibodies.

BACKGROUND: Monoclonal antibodies against proprotein convertase subtilisin/kexin type 9 (PCSK9i) lower LDL-C by up to 60% and increase plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) levels by 10-fold. OBJECTIVES: The authors studied the reasons behind the robust increase in plasma PCSK9 levels by testing the hypothesis that mechanisms beyond clearance via the low-density lipoprotein receptor (LDLR) contribute to the regulation of cholesterol homeostasis. METHODS: In clinical cohorts, animal models, and cell-based studies, we measured kinetic changes in PCSK9 production and clearance in response to PCSK9i. RESULTS: In a patient cohort receiving PCSK9i therapy, plasma PCSK9 levels rose 11-fold during the first 3 months and then plateaued for 15 months. In a cohort of healthy volunteers, a single injection of PCSK9i increased plasma PCSK9 levels within 12 hours; the rise continued for 9 days until it plateaued at 10-fold above baseline. We recapitulated the rapid rise in PCSK9 levels in a mouse model, but only in the presence of LDLR. In vivo turnover and in vitro pulse-chase studies identified 2 mechanisms contributing to the rapid increase in plasma PCSK9 levels in response to PCSK9i: 1) the expected delayed clearance of the antibody-bound PCSK9; and 2) the unexpected post-translational increase in PCSK9 secretion. CONCLUSIONS: PCSK9 re-entry to the liver via LDLR triggers a sensing loop regulating PCSK9 secretion. PCSK9i therapy enhances the secretion of PCSK9, an effect that contributes to the increased plasma PCSK9 levels in treated subjects.

Functional differences between two major ubiquitin receptors in the proteasome; S5a and hRpn13.

It is well known that S5a and hRpn13 are two major ubiquitin (Ub) receptors in the proteasome but little is known about their functional difference in recruiting ubiquitinated substrates. In this study using siRNA-mediated knockdown of S5a or hRpn13, we found that two Ub receptors had different substrate specificity although similar level of accumulation of high molecular weight Ub-conjugates was observed. Interesting enough, depletion of S5a, but not hRpn13, resulted in the Ub-containing aggregates and induced ER chaperones such as Grp78 and Grp94. ERAD substrates such as alpha-TCR and alpha1-antitrypsin were also stabilized by the depletion of S5a but not hRpn13. Our results suggest that there is different substrate specificity between S5a and hRpn13 at the level of delivery and S5a may be the major docking site for ERAD substrates.

Rubinstein-Taybi syndrome associated with Chiari type I malformation caused by a large 16p13.3 microdeletion: a contiguous gene syndrome?

Rubinstein-Taybi Syndrome (RSTS, OMIM 180849) is a rare condition, which in 65% of cases is caused by haploinsufficiency of CREBBP (cAMP response element binding protein binding protein) localized to 16p13.3. A small subset of RSTS cases caused by 16p13.3 microdeletions involving neighboring genes have been recently suggested to be a true contiguous gene syndrome called severe RSTS or 16p13.3 deletion syndrome (OMIM 610543). In the present report, we describe a case of a 2-year-old female with RSTS who, besides most of the typical features of RSTS has corpus callosum dysgenesis and a Chiari type I malformation which required neurosurgical decompression. CGH microarray showed a approximately 520.7 kb microdeletion on 16p13.3 involving CREBBP, ADCY9, and SRL genes. We hypothesize that the manifestations in this patient might be influenced by the haploinsufficiency for ADCY9 and SRL.

Emerging lipid lowering agents targeting LDL cholesterol.

Atherosclerotic cardiovascular disease (ASCVD) is the main cause of morbidity and mortality in the US. ASCVD is caused by elevated levels of ApoB lipoproteins, which over many years penetrate the arterial subendothelial space leading to plaque growth and eventually rupture causing clinical symptoms. ApoB lipoprotein levels are approximated in clinical practice by LDL-C measurement. LDL-C lowering agents (statins, ezetimibe, and PCSK9 inhibitors) reduce cardiovascular risk in primary and secondary prevention proportionally to LDL-C reduction (23% per 1 mmol/L of LDL). However, for a variety of reasons, many patients do not achieve their recommended LDL-C levels using currently available therapies. This has prompted the development of new LDL-C lowering drugs in the hope to reduce cardiovascular risk, such as bempedoic acid, inclisiran, gemcabene, and evinacumab. Drugs targeting other lipids (triglycerides, HDL-C, lipoprotein (a)), intravascular inflammation or acting by other mechanisms also have a role in atherosclerosis prevention, however, they will not be covered in this review. ABBREVIATIONS: ACLY: (ATP-citrate lyase); ANGPTL: (angiopoietin-like protein 3); ASCVD: (atherosclerotic cardiovascular disease); BPA: (bempedoic acid); CETP (cholesteryl ester transfer protein); CV: (cardiovascular); CVD: (cardiovascular diseases); FH (familial hypercholesterolemia); HMGCR (3-hydroxy-3-methyl-glutaryl-coenzyme A reductase); HoFH (homozygous FH); LDL-C: (low density lipoprotein cholesterol); LDL-P: (low density lipoprotein particle); LDLr: (low density lipoprotein receptor); NPC1L1: (Niemann-Pick C1-like 1 protein); PCSK9: (proprotein convertase subtilisin/kexin type 9); SREBP-2: (sterol regulatory element binding protein 2).

Entosis: From Cell Biology to Clinical Cancer Pathology.

Entosis is a phenomenon, in which one cell enters a second one. New clinico-histopathological studies of entosis prompted us to summarize its significance in cancer. It appears that entosis might be a novel, independent prognostic predictor factor in cancer histopathology. We briefly discuss the biological basis of entosis, followed by a summary of published clinico-histopathological studies on entosis significance in cancer prognosis. The correlation of entosis with cancer prognosis in head and neck squamous cell carcinoma, anal carcinoma, lung adenocarcinoma, pancreatic ductal carcinoma and breast ductal carcinoma, is shown. Numerous entotic figures are associated with a more malignant cancer phenotype and poor prognosis in many cancers. We also showed that some anticancer drugs could induce entosis in cell culture, even as an escape mechanism. Thus, entosis is likely beneficial for survival of malignant cells, i.e., an entotic cell can hide from unfavourable factors in another cell and subsequently leave the host cell remaining intact, leading to failure in therapy or cancer recurrence. Finally, we highlight the potential relationship of cell adhesion with entosis in vitro, based on the model of the BxPc3 cells cultured in full adhesive conditions, comparing them to a commonly used MCF7 semiadhesive model of entosis.

Analysis of Npl4 deletion mutants in mammalian cells unravels new Ufd1-interacting motifs and suggests a regulatory role of Npl4 in ERAD.

Npl4 is a 67 kDa protein forming a stable heterodimer with Ufd1, which in turn binds the ubiquitous p97/VCP ATPase. According to a widely accepted model, VCP(Ufd1-Npl4) promotes the retrotranslocation of emerging ER proteins, their ubiquitination by associated ligases, and handling to the 26S proteasome for degradation in a process known as ERAD (ER-associated degradation). Using a series of Npl4 deletion mutants we have revealed that the binding of Ufd1 to Npl4 is mediated by two regions: a conserved stretch of amino acids from 113 to 255 within the zf-Npl4 domain and by the Npl4 homology domain between amino acids 263 and 344. Within the first region, we have identified two discrete subdomains: one involved in Ufd1 binding and one regulating VCP binding. Expression of any one of the mutants failed to induce any changes in the morphology of the ER or Golgi compartments. Moreover, we have observed that overexpression of all the analyzed mutants induced mild ER stress, as evidenced by increased Grp74/BiP expression without associated XBP1 splicing or induction of apoptosis. Surprisingly, we have not observed any accumulation of the typical ERAD substrate alphaTCR. This favors the model where the Ufd1-Npl4 dimer forms a regulatory gate at the exit from the retrotranslocone, rather than actively promoting retrotranslocation like the p97VCP ATPase.