Methuosis: nonapoptotic cell death associated with vacuolization of macropinosome and endosome compartments

Perinuclear organelle trauma at the nexus of cardiomyopathy pathogenesis arising from loss of function LMNA mutation

Over the past 25 years, nuclear envelope (NE) perturbations have been reported in various experimental models with mutations in the LMNA gene. Although the hypothesis that NE perturbations from LMNA mutations are a fundamental feature of striated muscle damage has garnered wide acceptance, the molecular sequalae provoked by the NE damage and how they underlie disease pathogenesis such as cardiomyopathy (LMNA cardiomyopathy) remain poorly understood. We recently shed light on one such consequence, by employing a cardiomyocyte-specific Lmna deletion in vivo in the adult heart. We observed extensive NE perturbations prior to cardiac function deterioration with collateral damage in the perinuclear space. The Golgi is particularly affected, leading to cytoprotective stress responses that are likely disrupted by the progressive deterioration of the Golgi itself. In this review, we discuss the etiology of LMNA cardiomyopathy with perinuclear 'organelle trauma' as the nexus between NE damage and disease pathogenesis.

Methuosis key gene ARF6 as a diagnostic, prognostic and immunotherapeutic marker for prostate cancer: based on a comprehensive pan-cancer multi-omics analysis

BACKGROUND

Prostate cancer (PCa) is a leading cause of cancer-related mortality among men worldwide. Despite progress in the understanding of tumor biology, the prognosis for advanced prostate cancer remains poor, necessitating the identification of novel diagnostic, prognostic, and therapeutic biomarkers. Methuosis, a recently identified form of programmed cell death (PCD), is characterized by cytoplasmic vacuole accumulation and subsequent cell rupture, distinct from classical apoptosis and necrosis. The key regulatory gene in Methuosis, ARF6 (ADP-ribosylation factor 6), has emerged as a potential marker for cancer diagnosis and treatment. However, its role in prostate cancer and other malignancies remains insufficiently understood.

METHODS

In this study, we performed a comprehensive pan-cancer multi-omics analysis to investigate the role of ARF6 in Methuosis across multiple cancer types, with a specific focus on PCa as the primary context. Using data from public databases, including RNA sequencing, gene expression profiling, and clinical outcomes, we assessed the association between ARF6 expression and patient prognosis in PCa within this broader pan-cancer framework. Additionally, we employed functional enrichment analyses and survival analysis to explore the potential of ARF6 as a diagnostic and prognostic marker for prostate cancer. Immunotherapy-related gene expression signatures were also evaluated to determine the therapeutic relevance of ARF6.

RESULTS

ARF6 was significantly overexpressed in PCa tissues compared to normal tissues and was associated with poor prognosis (p < 0.05), particularly in advanced and metastatic stages. Receiver operating characteristic (ROC) analysis revealed a diagnostic AUC of 0.792 for ARF6. Functional analyses indicated that ARF6 regulates pathways critical to cell migration, invasion, and drug resistance. Moreover, ARF6 expression showed a strong negative correlation with immune checkpoint markers, such as PD-L1 (r = - 0.74), suggesting its potential as an immunotherapy target. These findings underscore ARF6's pivotal role in Methuosis and its promise as a biomarker in PCa.

CONCLUSION

ARF6 is a key regulator of Methuosis in prostate cancer, contributing to tumor progression, metastasis, and resistance to treatment. Our findings support the potential of ARF6 as a diagnostic, prognostic, and immunotherapeutic target in prostate cancer. Further experimental validation is needed to confirm these observations and to explore the therapeutic implications of targeting ARF6 in cancer treatment.

Potential Role of CD99 Signaling Pathway in Schwann Cell Dysfunction in Diabetic Foot Ulcers Based on Single-Cell Transcriptome Analysis

Background: Schwann cell (SC) dysfunction contributes to the delayed healing of diabetic foot ulcers (DFUs). However, the underlying molecular mechanism regarding the unregulated SC function is poorly understood. Thus, we examined the single-cell transcriptome data from different DFU states focusing on SC characteristics. Methods: The single-cell RNA sequencing (scRNA-seq) data of DFU was obtained from the Gene Expression Omnibus (GEO) database, covering foot skin samples from nondiabetic patients, diabetic patients without DFU, DFU healers, and DFU nonhealers. After scRNA-seq data processing, downscaling, and cell cluster identification, cell communication analysis was performed by the CellChat package. Furthermore, we subclustered SC populations and ran the trajectory inference and pseudotime analysis to investigate the dynamic changes in SC. Finally, the significant pathways were validated with a db/db mouse wound model. Results: scRNA-seq analysis revealed different SC percentages and gene markers across the DFU groups. We identified that the CD99 signaling pathway was upregulated in the DFU nonhealer group. In the db/db mouse wound model, we observed that CD99 was highly expressed in the demyelinated area of the peripheral nerve fibers. Conclusion: Our study elucidated that the CD99 pathway activation may play a crucial role in SC dysfunction of DFU, providing insights into the peripheral glia regulation mechanism and potential therapeutic target of DFU.

Lytic photoreceptor cell death caused by Rab escort protein deficiency in Drosophila

Choroideremia (CHM) is a rare X-linked recessive form of inherited retinal degeneration caused by the deficiency of the Rab escort protein 1 (REP1)-encoding CHM gene. REP1 is essential for the post-translational prenylation of the key players in intracellular membrane trafficking, the Rab GTPases. In this study, we aimed to analyze the mechanisms of retinal degeneration caused by Rep deficiency using the Drosophila retina as a model system. Rab GTPases lost their membrane association ability and diffused into the cytoplasm, and the accumulation of unprenylated Rab6 and Rab7 was observed in Rep-deficient photoreceptors. Notably, Rep-deficient photoreceptors underwent progressive cell death via cell swelling and rupture rather than apoptosis. These findings provide new insight to seek a therapeutic approach to CHM. Impact statement Choroideremia is an inherited retinal degeneration caused by a deficiency of Rab escort protein 1 (Rep-1). We used the Drosophila retina as a model to study the mechanism of retinal degeneration in Rep-deficiency and found that Rep-deficient photoreceptors undergo progressive cell death via cell swelling and rupture rather than apoptosis.

Cytoplasmic Vacuolization: A Fascinating Morphological Alteration From Cellular Stress to Cell Death

Cytoplasmic vacuolization is a cellular morphological alteration characterized by the presence of substantial vacuole-like structures originating from various cellular organelles. This phenomenon is often observed in various anticancer treatments, including chemotherapeutic drugs, and photodynamic therapy (PDT), and is frequently linked with cell death. Nevertheless, the precise mechanisms underlying cytoplasmic vacuolization and ensuing cell death remain ambiguous. Cytoplasmic vacuolization associated cell death (CVACD) is a complex process characterized by cellular stress, encompassing ER stress, heightened membrane permeability, ion imbalance, and mitochondrial dysfunction. The MAPK signaling pathway is closely associated with the activation of CVACD. This review provides a thorough examination of contemporary studies on cytoplasmic vacuolization in mammalian cells, elucidating its etiology, origins, and molecular pathways. Additionally, it highlights the potential of CVACD as an innovative therapeutic strategy for cancer.

Survival strategies of cancer cells: the role of macropinocytosis in nutrient acquisition, metabolic reprogramming, and therapeutic targeting

Macropinocytosis is a nonselective form of endocytosis that allows cancer cells to largely take up the extracellular fluid and its contents, including nutrients, growth factors, etc. We first elaborate meticulously on the process of macropinocytosis. Only by thoroughly understanding this entire process can we devise targeted strategies against it. We then focus on the central role of the MTOR (mechanistic target of rapamycin kinase) complex 1 (MTORC1) in regulating macropinocytosis, highlighting its significance as a key signaling hub where various pathways converge to control nutrient uptake and metabolic processes. The article covers a comprehensive analysis of the literature on the molecular mechanisms governing macropinocytosis, including the initiation, maturation, and recycling of macropinosomes, with an emphasis on how these processes are hijacked by cancer cells to sustain their growth. Key discussions include the potential therapeutic strategies targeting macropinocytosis, such as enhancing drug delivery via this pathway, inhibiting macropinocytosis to starve cancer cells, blocking the degradation and recycling of macropinosomes, and inducing methuosis - a form of cell death triggered by excessive macropinocytosis. Targeting macropinocytosis represents a novel and innovative approach that could significantly advance the treatment of cancers that rely on this pathway for survival. Through continuous research and innovation, we look forward to developing more effective and safer anti-cancer therapies that will bring new hope to patients.Abbreviation: AMPK: AMP-activated protein kinase; ASOs: antisense oligonucleotides; CAD: carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase; DC: dendritic cell; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; ERBB2: erb-b2 receptor tyrosine kinase 2; ESCRT: endosomal sorting complex required for transport; GAP: GTPase-activating protein; GEF: guanine nucleotide exchange factor; GRB2: growth factor receptor bound protein 2; LPP: lipopolyplex; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; MTORC2: mechanistic target of rapamycin kinase complex 2; NSCLC: non-small cell lung cancer; PADC: pancreatic ductal adenocarcinoma; PDPK1: 3-phosphoinositide dependent protein kinase 1; PI3K: phosphoinositide 3-kinase; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PtdIns(3,4,5)P3: phosphatidylinositol-(3,4,5)-trisphosphate; PtdIns(4,5)P2: phosphatidylinositol-(4,5)-bisphosphate; PTT: photothermal therapies; RAC1: Rac family small GTPase 1; RPS6: ribosomal protein S6; RPS6KB1: ribosomal protein S6 kinase B1; RTKs: receptor tyrosine kinases; SREBF: sterol regulatory element binding transcription factor; TFEB: transcription factor EB; TNBC: triple-negative breast cancer; TSC2: TSC complex subunit 2; ULK1: unc-51 like autophagy activating kinase 1; UPS: ubiquitin-proteasome system.

Multimodal antiproliferative effects of oleanolic acid mitocans: In vitro and in vivo studies

Mitochondria-targeting drugs (mitocans) based on organic cations are emerging as powerful and selective cancer therapeutics. In this study, we have evaluated a novel series of oleanolic acid-derived mitocans, revealing nanomolar-range antiproliferative effects against human solid tumor cells. Continuous live-cell imaging revealed extensive cytoplasmic vacuolation, while mechanistic studies identified paraptosis as the dominant form of cell death. Remarkably, in vivo experiments demonstrated significant tumor growth inhibition in mice, with no detectable toxicity at therapeutic doses. These findings highlight the potential of oleanolic acid-derived mitocans as promising candidates for cancer therapy.

Dual targeting PPARα and NPC1L1 metabolic vulnerabilities blocks tumorigenesis

Dysregulated lipid metabolism is linked to tumor progression. In this study, we identified Niemann-Pick C1-like 1 (NPC1L1) as a downstream effector of PKM2. In breast cancer cells, PKM2 knockout (KO) enhanced NPC1L1 expression while downregulating peroxisome proliferator-activated receptor α (PPARα) signaling pathway. PPARα and nuclear factor-E2 p45-related factor 1/2(Nrf1/2) are transcription factors regulating NPC1L1. In vitro PKM2 KO enhanced recruitment of Nrf1/2 to the NPC1L1 promoter region. Fenofibrate, a PPARα activator, promoted NPC1L1 expression; ezetimibe, an NPC1L1 inhibitor and effective Nrf2 activator, also elevated NPC1L1 expression. Combined administration of fenofibrate and ezetimibe significantly induced cytoplasmic vacuolation, and cell apoptosis. Mechanistically, this combined administration activated inositol required enzyme 1α(IRE1α) and produced the spliced form of X-box binding protein (XBP1s), which in turn enhanced lysine demethylase 6B (KDM6B) transcription. XBP1s interacts with KDM6B to activate genes involved in the unfolded protein response by demethylating di- and tri-methylated lysine 27 of histone H3 (H3K27), consequently increasing H3K27 acetylation levels in breast cancer cell lines. Fenofibrate and ezetimibe synergistically inhibited tumor growth in vivo. Our findings reveal that dual targeting of PPARα and NPC1L1 may represent a novel therapeutic regimen for breast cancer therapy.

Inhibition of platin-induced BCL2 increase overcomes chemoresistance in squamous cell carcinoma of the head and neck through resensitization to cell death

The clinical outcome of head and neck squamous cell carcinoma (HNSCC) remains poor with high recurrence rates, in part due to resistance to concurrent platinum-based chemotherapy. The anti-apoptotic BCL2 protein is involved in apoptosis resistance and tumor cell invasion/migration. Here, we test whether BCL2 overexpression predicts poor therapeutic response of HNSCC to cisplatin-based chemoradiotherapy and the effects of selective BCL2 inhibition on cisplatin-induced cell changes in vitro. BCL2 immunostatus was correlated with survival after chemoradiotherapy in a uniformly treated HNSCC cohort. The combination therapy of ABT-199, a BCL2 inhibitor, and cisplatin was evaluated in vitro using corresponding patient-derived cell lines. Colony formation and the mode of cell death were analyzed in-depth. Patients with BCL2-positive tumors (44/254) prior to treatment (either radiation, cisplatin monotherapy, or both) had shorter overall and progression-free survival (log-rank; p = 0.048) and a higher rate of tumor relapse (Fisher's exact test; p = 0.0032). BCL2 inhibition alone had no effect on cell functions in our triple panel of cisplatin-sensitive cell lines but enhanced cisplatin-induced effects. Rates of autophagy and cell death, including methuosis, were doubled, while epithelial-mesenchymal transformation was inhibited. As selective inhibition of BCL2 is available and standard of care in other malignancies, its immunohistochemical assessment could help personalize therapy by identifying a subpopulation to overcome chemoresistance, particularly in locally advanced HNSCC.

TMC7 is required for spermiogenesis and male fertility by regulating TGN-derived vesicles

Infertility affects 10-12 % of couples worldwide, 50 % of which are male. Abnormal spermatogenesis is among the main causes of male infertility. We were curious about the possible role of transmembrane channel-like protein 7 (TMC7) in spermatogenesis because of its aberrant expression in several male infertility patients. In this study, we found that deletion of Tmc7, which is highly expressed during spermiogenesis, causes a human oligoasthenoteratozoospermia (OAT)-like phenotype in male mice. By histological analysis, TEM, RNA-seq and library-free data-independent acquisition mass spectrometry (DIA-MS) of TMC7-null mouse testes, we found that Tmc7 deletion caused abnormal swelling of trans-Golgi network (TGN) vesicles in elongated spermatids. Further immunofluorescence localization analysis revealed that these vesicles were defined by synaptophysin-like 1 (SYPL1). In addition, TMC7 may act as a potential chloride transport channel to regulate the size of transport vesicles. In conclusion, this study demonstrated that TMC7 is essential for male fertility and may be used as a potential protein for the identification and recognition of OAT. On the other hand, TMC7 may be a potential male contraceptive target.

Kinase Inhibitor-Induced Cell-Type Specific Vacuole Formation in the Absence of Canonical ATG5-Dependent Autophagy Initiation Pathway

Pyridinyl-imidazole class p38 MAPKα/β (MAPK14/MAPK11) inhibitors including SB202190 have been shown to induce cell-type specific defective autophagy resulting in micron-scale vacuole formation, cell death, and tumor suppression. We had earlier shown that this is an off-target effect of SB202190. Here we provide evidence that this vacuole formation is independent of ATG5-mediated canonical autophagosome initiation. While SB202190 interferes with autophagic flux in many cell lines parallel to vacuolation, autophagy-deficient DU-145 cells and CRISPR/Cas9 gene-edited ATG5-knockout A549 cells also undergo vacuolation upon SB202190 treatment. Late-endosomal GTPase RAB7 colocalizes with these compartments and RAB7 GTP-binding is essential for SB202190-induced vacuolation. A screen for modulators of SB202190-induced vacuolation revealed molecules including multi-kinase inhibitor sorafenib as inhibitors of vacuolation and sorafenib co-treatment enhanced cytotoxicity of SB202190. Moreover, VE-821, an ATR inhibitor was found to phenocopy the cell-type specific vacuolation response of SB202190. To identify the factors determining the cell-type specificity of vacuolation induced by SB-compounds and VE-821, we compared the transcriptomics data from vacuole-forming and non-vacuole-forming cancer cell lines and identified a gene expression signature that may define sensitivity of cells to these small-molecules. Further analyses using small molecule tools and the gene signature discovered here, could reveal novel mechanisms regulating this interesting anti-cancer phenotype.

Function of CSNK2/CK2 selectively affects the endoplasmic reticulum and the Golgi apparatus in mtor-mediated autophagy induction

Selective macroautophagy/autophagy of the endoplasmic reticulum, known as reticulophagy/ER-phagy, is essential to maintain ER homeostasis. We recently showed that members of the autophagy receptor family RETREG/FAM134 are regulated by phosphorylation-dependent ubiquitination. In an unbiased screen we had identified several kinases downstream of MTOR with profound impact on reticulophagy flux, including ATR and CSNK2/CK2. Inhibition of CSNK2 by SGC-CK2-1 prevented regulatory ubiquitination of RETREG1/FAM134B and RETREG3/FAM134C upon autophagy activation as well as the formation of high-density RETREG1- and RETREG3-clusters. Here we report on additional resource data of global proteomics upon CSNK2 and ATR inhibition, respectively. Our data suggests that the function of CSNK2 is mainly limited to the ER/reticulophagy and Golgi/Golgiphagy, while ATR inhibition by VE-822 affects the vast majority of organelles/selective autophagy pathways.Abbreviation: ATRi: ATR inhibitor VE-822; CSNK2i: CSNK2 inhibitor SGC-CK2-1; ER: endoplasmic reticulum.

Tanshinlactone triggers methuosis in breast cancer cells via NRF2 activation

Background

Tanshinlactone is a compound derived from the herb Salvia miltiorrhiza. Breast cancer is the most prevalent malignancy among women globally. While significant strides have been made in breast cancer management, these interventions are often impeded by substantial adverse effects that undermine patients' quality of life and confront limitations due to the eventual development of multi-drug resistance. Catastrophic macropinocytosis, also called methuosis, as a nonapoptotic cell death associated with cytoplasmic vacuolization, has gained increasing attention, largely because of its potential importance in cancer therapy.

Methods

The effect of tanshinlactone on the growth of human cancer cells was evaluated using sulforhodamine B and colony formation assay. Fluorescent dyes are used to label macropinosomes and lysosomes. Phase contrast, confocal and transmission electron microscopy were employed to observe cell morphological changes. RT-PCR, western blot, lentiviral-mediated gene overexpression, and pharmacological inhibitor assays were comprehensively designed to regulate the identified signaling pathways and confirm the mechanism of tanshinlactone. Human breast cancer cell lines-derived xenograft tumor explants assay was used to evaluate the compound's efficacy and to assess the induction of methuosis via NRF2 activation by tanshinlactone.

Results

Tanshinlactone selectively inhibits the growth of ER+ and HER2+/EGFR + breast cancer cells while showing limited cytotoxicity against other cancer types and normal cells. The selective anti-breast cancer activity is associated with the induction of methuosis, characterized by cytoplasmic vacuolization due to dysfunctional macropinocytosis. This process is mediated by the activation of the transcription factor NRF2, leading to the formation of macropinosomes that fail to fuse with lysosomes or recycle to the plasma membrane, resulting in cell death. The in vitro induction of methuosis via NRF2 activation was replicated in a murine xenograft explants model. Additionally, tanshinlactone demonstrated effectiveness against lapatinib-resistant breast cancer cells, suggesting its potential as a therapeutic agent for overcoming drug resistance in cancer treatment.

Conclusion

Tanshinlactone as a novel therapeutic agent, is capable of selectively inhibiting ER+ and HER2+/EGFR + breast tumors through a unique mechanism of inducing catastrophic macropinocytosis. This regimen holds promise for targeted therapy with minimized side effects and offers a new therapeutic avenue for breast patients with drug-resistant diseases.

Live and let die: analyzing ultrastructural features in cell death

Cell death is an important process that supports morphogenesis during development and tissue homeostasis during adult life by removing damaged or unwanted cells and its dysregulation is associated with numerous disease states. There are different pathways through which a cell can undergo cell death, each relying on peculiar molecular mechanisms and morpho-ultrastructural features. To date, however, while molecular and genetic approaches have been successfully integrated into the field, cell death studies rarely incorporate ultrastructural data from electron microscopy. This review article reports a gallery of original transmission electron microscopy images to describe the ultrastructural features of cells undergoing different types of cell death programs, including necrosis, apoptosis, autophagy, mitotic catastrophe, ferroptosis, methuosis, and paraptosis. TEM has been an important technology in cell biology for well over 50 years and still continues to offer significant advantages in the area of cell death research. TEM allows detailed characterization of the ultrastructural changes within the cell, such as the alteration of organelles and subcellular structures, the nuclear reorganization, and the loss of membrane integrity that enable a distinction between the different forms of cell death based on morphological criteria. Possible pitfalls are also described.

Methuosis, Alkaliptosis, and Oxeiptosis and Their Significance in Anticancer Therapy

Understanding morphological, biochemical, and functional aspects of cell death is essential for targeting new cancer therapies. Even though many different mechanisms of cell death are identified, it is crucial to highlight the role of new and lesser-known pathways, including methuosis, alkaliptosis, and oxeiptosis. The aim of this review was to summarize the data about cell death mechanisms-methuosis, alkaliptosis, and oxeiptosis-and their role in cancer treatment. Unique molecular mechanisms and cellular outcomes characterize each of these forms of cell death. This research on methuosis, alkaliptosis, and oxeiptosis provides a better understating of cell death biology and creates novel opportunities for neoplasm management.

Navigating the complexities of cell death: Insights into accidental and programmed cell death

Cell death is a critical biological phenomenon that can be categorized into accidental cell death (ACD) and programmed cell death (PCD), each exhibiting distinct signaling, mechanistic and morphological characteristics. This paper provides a comprehensive overview of seven types of ACD, including coagulative, liquefactive, caseous, fat, fibrinoid, gangrenous and secondary necrosis, discussing their pathological implications in conditions such as ischemia and inflammation. Additionally, we review eighteen forms of PCD, encompassing autophagy, apoptosis, necroptosis, pyroptosis, paraptosis, ferroptosis, anoikis, entosis, NETosis, eryptosis, parthanatos, mitoptosis, and newly recognized types such as methuosis, autosis, alkaliptosis, oxeiptosis, cuprotosis and erebosis. The implications of these cell death modalities for cellular processes, development, and disease-particularly in the context of neoplastic and neurodegenerative disorders-are also covered. Furthermore, we explore the crosstalk between various forms of PCD, emphasizing how apoptotic mechanisms can influence pathways like necroptosis and pyroptosis. Understanding this interplay is crucial for elucidating cellular responses to stress, as well as for its potential relevance in clinical applications and therapeutic strategies. Future research should focus on clarifying the molecular mechanisms that govern different forms of PCD and their interactions.

Delayed vacuolation in mammalian cells caused by hypotonicity and ion loss

Prolonged exposure of mammalian cells to hypotonic environments stimulates the development of sometimes large and numerous vacuoles of unknown origin. Here, we investigate the nature and formation of these vacuoles, which we term LateVacs. Vacuolation starts after osmotic cell swelling has subsided and continues for many hours thereafter. Most of the vacuoles are positive for the lysosomal marker LAMP-1 but not for the autophagosomal marker LC3. Vacuoles do not appear to have acidic pH, as they exclude LysoTracker and acridine orange; inhibiting the V-ATPase with bafilomycin A1 has no effect on their formation. No LateVacs were formed in cells with a knockout of the essential LRRC8A subunit of the volume-regulated anion channel (VRAC). Since the main feature of cells recovered from hypotonic swelling should be reduced chloride concentration, we tested if chloride depletion can act as a signal for vacuolation. Indeed, four different low-chloride buffers resulted in the development of similar vacuoles. Moreover, vacuolation was suppressed in WNK1/WNK3 double knockouts or by the inhibition of WNK kinase, which is activated by low chloride; in hypotonic media, the WNK inhibitor had a similar effect. However, exposing cells to a low-sodium, high-potassium medium also resulted in vacuoles, which were insensitive to WNK. We conclude that vacuole development can be triggered either by the loss of chloride or by the loss of sodium.

Formation of a giant unilocular vacuole via macropinocytosis-like process confers anoikis resistance

Cell survival in metazoans depends on cell attachment to the extracellular matrix (ECM) or to neighboring cells. Loss of such attachment triggers a type of programmed cell death known as anoikis, the acquisition of resistance to which is a key step in cancer development. The mechanisms underlying anoikis resistance remain unclear, however. The intracellular F-actin cytoskeleton plays a key role in sensing the loss of cell-ECM attachment, but how its disruption affects cell fate during such stress is not well understood. Here, we reveal a cell survival strategy characterized by the formation of a giant unilocular vacuole (GUVac) in the cytoplasm of the cells whose actin cytoskeleton is disrupted during loss of matrix attachment. Time-lapse imaging and electron microscopy showed that large vacuoles with a diameter of >500 nm accumulated early after inhibition of actin polymerization in cells in suspension culture, and that these vacuoles subsequently coalesced to form a GUVac. GUVac formation was found to result from a variation of a macropinocytosis-like process, characterized by the presence of inwardly curved membrane invaginations. This phenomenon relies on both F-actin depolymerization and the recruitment of septin proteins for micron-sized plasma membrane invagination. The vacuole fusion step during GUVac formation requires PI(3)P produced by VPS34 and PI3K-C2α on the surface of vacuoles. Furthermore, its induction after loss of matrix attachment conferred anoikis resistance. Our results thus show that the formation of a previously unrecognized organelle promotes cell survival in the face of altered actin and matrix environments.

Exploring paraptosis as a therapeutic approach in cancer treatment

A variety of cell death pathways play critical roles in the onset and progression of multiple diseases. Paraptosis, a unique form of programmed cell death, has gained significant attention in recent years. Unlike apoptosis and necrosis, paraptosis is characterized by cytoplasmic vacuolization, swelling of the endoplasmic reticulum and mitochondria, and the absence of caspase activation. Numerous natural products, synthetic compounds, and newly launched nanomedicines have been demonstrated to prime cell death through the paraptotic program and may offer novel therapeutic strategies for cancer treatment. This review summarizes recent findings, delineates the intricate network of signaling pathways underlying paraptosis, and discusses the potential therapeutic implications of targeting paraptosis in cancer treatment. The aim of this review is to expand our understanding of this unique cell death process and explore the potential therapeutic implications of targeting paraptosis in cancer treatment.

Massive entry of BK Polyomavirus induces transient cytoplasmic vacuolization of human renal proximal tubule epithelial cells

BK polyomavirus (BKPyV) is a ubiquitous human virus that establishes a persistent infection in renal tubular epithelial cells and mainly causes disease in kidney transplant recipients. The closely related simian polyomavirus SV40 is known to cause cytoplasmic vacuolization in simian kidney cells, possibly increasing progeny release and cell death. This study aimed to determine whether BKPyV causes cytoplasmic vacuolization in primary human renal proximal tubule epithelial cells (RPTECs) and to investigate its potential role in the replication cycle. Using a large infectious dose (MOI 100-1000), a fraction of RPTECs (10-72%) showed early-wave vacuolization from 3 hours post-infection (hpi), which was mainly reversed by 36 hpi. Independent of the infectious dose, late-wave vacuolization occurred around the timepoint of progeny release. BKPyV receptor binding and internalization were required, as neuraminidase pretreatment and preincubation or treatment with a BKPyV-specific neutralizing antibody prevented early or late-occurring vacuolization. Microscopy revealed that the vacuoles were enlarged acidic endo-/lysosomal structures (dextran, EEA1, Rab5, Rab7, LAMP1, and/or Lysoview positive) that contained membrane-bound BKPyV. Time-lapse microscopy and quantitative PCR revealed that cell death and progeny release preceded late-wave vacuolization, mainly affecting cells directly neighboring the lysed cells. Thus, vacuolization had little impact on cell death or progeny release. Addition of the V-ATPase inhibitor Bafilomycin A1 at 0 hpi blocked vacuolization and BKPyV replication, but addition at 2 hpi only blocked vacuolization, suggesting that continuous endosomal acidification and maturation is needed for vacuole formation, but not for BKPyV replication. Our study shows that a massive uptake of BKPyV in RPTECs induces transient enlargement of endo-/lysosomes and is an early event in the viral replication cycle. Vacuolization gives no clear benefit for BKPyV and is possibly the result of a transiently overloaded endocytic pathway. Focal vacuolization around lysed cells suggests that the spread of BKPyV is preferably local.

Functional genomic screens with death rate analyses reveal mechanisms of drug action

A common approach for understanding how drugs induce their therapeutic effects is to identify the genetic determinants of drug sensitivity. Because 'chemo-genetic profiles' are performed in a pooled format, inference of gene function is subject to several confounding influences related to variation in growth rates between clones. In this study, we developed Method for Evaluating Death Using a Simulation-assisted Approach (MEDUSA), which uses time-resolved measurements, along with model-driven constraints, to reveal the combination of growth and death rates that generated the observed drug response. MEDUSA is uniquely effective at identifying death regulatory genes. We apply MEDUSA to characterize DNA damage-induced lethality in the presence and absence of p53. Loss of p53 switches the mechanism of DNA damage-induced death from apoptosis to a non-apoptotic death that requires high respiration. These findings demonstrate the utility of MEDUSA both for determining the genetic dependencies of lethality and for revealing opportunities to potentiate chemo-efficacy in a cancer-specific manner.

Methuosis Inducer SGI-1027 Cooperates with Everolimus to Promote Apoptosis and Pyroptosis by Triggering Lysosomal Membrane Permeability in Renal Cancer

The mTOR inhibitor everolimus has been approved as a sequential or second-line therapy for renal cell carcinoma (RCC). However, the development of drug resistance limits its clinical applications. This study aims to address the challenge of everolimus resistance and provide new insights into the treatment of advanced RCC. Here, the cytotoxicity of the DNA methyltransferase 1 (DNMT1) inhibitor SGI-1027 in inducing cell vacuolation and methuosis is discovered and demonstrated for the first time. Additionally, SGI-1027 exerts synergistic effects with everolimus, as their combination suppresses the growth, migration, and invasion of renal cancer cells. Mechanistically, apoptosis and GSDME-dependent pyroptosis triggered by lysosomal membrane permeability (LMP) are observed. The upregulation of GSDME expression and increased lysosomal activity in renal cancer cells provide a therapeutic window for the combination of these two drugs to treat renal cancer. The combination treatment exhibits effective anti-tumor activity and is well tolerated in a subcutaneous tumor model. Overall, this study validates and reveals the specific cytotoxicity property of SGI-1027 and its potent synergistic effect with everolimus, offering new insights into advanced RCC therapy and everolimus-resistance overcoming.

Repurposing methuosis-inducing anticancer drugs for anthelmintic therapy

Drug-resistant parasitic nematodes pose a grave threat to plants, animals, and humans. An innovative paradigm for treating parasitic nematodes is emphasized in this opinion. This approach relies on repurposing methuosis (a death characterized by accumulation of large vacuoles) inducing anticancer drugs as anthelmintics. We review drugs/chemicals that have shown to kill nematodes or cancerous cells by inducing multiple vacuoles that eventually coalesce and rupture. This perspective additionally offers a succinct summary on Structure-Activity Relationship (SAR) of methuosis-inducing small molecules. This strategy holds promise for the development of broad-spectrum anthelmintics, shedding light on shared molecular mechanisms between cancer and nematodes in response to these inducers, thereby potentially transforming both therapeutic domains.

Novel selective inhibitors of macropinocytosis-dependent growth in pancreatic ductal carcinoma

Macropinocytosis is a cellular process that enables cells to engulf extracellular material, such as nutrients, growth factors, and even whole cells. It is involved in several physiological functions as well as pathological conditions. In cancer cells, macropinocytosis plays a crucial role in promoting tumor growth and survival under nutrient-limited conditions. In particular KRAS mutations have been identified as main drivers of macropinocytosis in pancreatic, breast, and non-small cell lung cancers. We performed a high-content screening to identify inhibitors of macropinocytosis in pancreatic ductal adenocarcinoma (PDAC)-derived cells, aiming to prevent nutrient scavenging of PDAC tumors. The screening campaign was conducted in a well-known pancreatic KRAS-mutated cell line (MIAPaCa-2) cultured under nutrient deprivation and using FITC-dextran to precisely quantify macropinocytosis. We assembled a collection of 3584 small molecules, including drugs approved by the Food and Drug Administration (FDA), drug-like molecules against molecular targets, kinase-targeted compounds, and molecules designed to hamper protein-protein interactions. We identified 28 molecules that inhibited macropinocytosis, with potency ranging from 0.4 to 29.9 μM (EC50). A few of them interfered with other endocytic pathways, while 11 compounds did not and were therefore considered specific "bona fide" macropinocytosis inhibitors and further characterized. Four compounds (Ivermectin, Tyrphostin A9, LY2090314, and Pyrvinium Pamoate) selectively hampered nutrient scavenging in KRAS-mutated cancer cells. Their ability to impair albumin-dependent proliferation was replicated both in different 2D cell culture systems and 3D organotypic models. These findings provide a new set of compounds specifically targeting macropinocytosis, which could have therapeutic applications in cancer and infectious diseases.

Approaches to selective and potent inhibition of glioblastoma by vanadyl complexes: Inducing mitotic catastrophe and methuosis

Drug resistance has been a major problem for cancer chemotherapy, especially for glioblastoma multiforme that is aggressive, heterogeneous and recurrent with <3% of a five-year survival and limited methods of clinical treatment. To overcome the problem, great efforts have recently been put in searching for agents inducing death of tumor cells via various non-apoptotic pathways. In the present work, we report for the first time that vanadyl complexes, i.e. bis(acetylacetonato)oxidovanadium (IV) (VO(acac)2), can cause mitotic catastrophe and methuotic death featured by catastrophic macropinocytic vacuole accumulation particularly in glioblastoma cells (GCs). Hence, VO(acac)2 strongly suppressed growth of GCs with both in vitro (IC50 = 4-6 μM) and in vivo models, and is much more potent than the current standard-of-care drug Temozolomide. The selective index is as high as ∼10 or more on GCs over normal neural cells. Importantly, GCs respond well to vanadium treatment regardless whether they are carrying IDH1 wild type gene that causes drug resistance. VO(acac)2 may induce methuosis via the Rac-Mitogen-activated protein kinase kinase 4 (MKK4)-c-Jun N-terminal kinase (JNK) signaling pathway. Furthermore, VO(acac)2-induced methuosis is not through a immunogenicity mechanism, making vanadyl complexes safe for interventional therapy. Overall, our results may encourage development of novel vanadium complexes promising for treatment of neural malignant tumor cells.

Cycloheptylprodigiosin from marine bacterium Spartinivicinus ruber MCCC 1K03745T induces a novel form of cell death characterized by Golgi disruption and enhanced secretion of cathepsin D in non-small cell lung cancer cell lines

Prodiginines have been studied extensively for their anticancer activity, however, the majority of the research has focused on prodigiosin. In this study, cycloheptylprodigiosin (S-1) is extracted from marine bacterium Spartinivicinus ruber MCCC 1K03745T, and its anticancer property was investigated. It exhibits remarkable cytotoxicity against a panel of human lung cancer cell lines, with the IC50 values ranging from 84.89 nM to 661.2 nM. After 6 h of treatment, S-1 gradually accumulates on mitochondria and lysosomes. While lower doses of S-1 induce cell cycle arrest, treatment with higher doses results in cell death in apoptotic independent manner in both NCI-H1299 and NCI-H460 cell lines. Interestingly, treatment with S-1 leads to the accumulation of LC3B-II via pathways that vary among different cell lines. In addition to its role as an autophagy inhibitor, S-1 also promotes autophagy initiation as demonstrated by the increment of EGFP fragment in the EGFP-LC3 degradation assay, however, inhibition of autophagy does not rescue cells from death induced by S-1. Mechanistically, S-1 impairs autophagic flux through disrupting acidic lysosomal pH and blocking the maturation of cathepsin D. Moreover, treatment with S-1 enhanced secretion of both pro- and mature forms of cathepsin D, coincident with disintegration of trans-Golgi network. Interestingly, S-1 does not induce ferroptosis, pyroptosis or necroptosis in NCI-H1299 cells. However, treatment of NCI-H460 cells with S-1 induces methuosis, which can be suppressed by Rac1 inhibitor EHT 1864. Our data demonstrate that S-1 is an effective anticancer agent with potential therapeutic application.

Cellular Regulation of Macropinocytosis

Interest in macropinocytosis has risen in recent years owing to its function in tumorigenesis, immune reaction, and viral infection. Cancer cells utilize macropinocytosis to acquire nutrients to support their uncontrolled proliferation and energy consumption. Macropinocytosis, a highly dynamic endocytic and vesicular process, is regulated by a series of cellular signaling pathways. The activation of small GTPases in conjunction with phosphoinositide signaling pivotally regulates the process of macropinocytosis. In this review, we summarize important findings about the regulation of macropinocytosis and provide information to increase our understanding of the regulatory mechanism underlying it.

Studies on Autophagy and Apoptosis of Fibrosarcoma HT-1080 Cells Mediated by Chalcone with Indole Moiety

This study demonstrated the anticancer efficacy of chalcones with indole moiety (MIPP, MOMIPP) in fibrosarcoma cells for the first time. The results showed that MIPP and MOMIPP reduced the viability of HT-1080 cells in a concentration-dependent manner. MOMIPP was more active than MIPP in HT-1080 cells, showing lower IC50 values (3.67 vs. 29.90 μM). Both compounds at a concentration of 1 μM induced apoptosis in HT-1080 cells, causing death strictly related to caspase activation, as cell viability was restored when the caspase inhibitor Z-VAD was added. Reactive oxygen species production was approximately 3-fold higher than in control cells, and cotreatment with the inhibitor of mitochondrial ATPase oligomycin diminished this effect. Such effects were also reflected in mitochondrial dysfunction, including decreased membrane potential. Interestingly, the compounds that were studied caused massive vacuolization in HT-1080 cells. Immunocytochemical staining and TEM analysis showed that HT-1080 cells exhibited increased expression of the LC3-II protein and the presence of autophagosomes with a double membrane, respectively. Both compounds induced apoptosis, highlighting a promising link between autophagy and apoptosis. This connection could be a new target for therapeutic strategies to overcome chemoresistance, which is a significant cause of treatment failure and tumour recurrence in fibrosarcoma following traditional chemotherapy.

Perinuclear damage from nuclear envelope deterioration elicits stress responses that contribute to LMNA cardiomyopathy

Mutations in the LMNA gene encoding lamins A/C cause an array of tissue-selective diseases, with the heart being the most commonly affected organ. Despite progress in understanding the perturbations emanating from LMNA mutations, an integrative understanding of the pathogenesis underlying cardiac dysfunction remains elusive. Using a novel conditional deletion model capable of translatome profiling, we observed that cardiomyocyte-specific Lmna deletion in adult mice led to rapid cardiomyopathy with pathological remodeling. Before cardiac dysfunction, Lmna-deleted cardiomyocytes displayed nuclear abnormalities, Golgi dilation/fragmentation, and CREB3-mediated stress activation. Translatome profiling identified MED25 activation, a transcriptional cofactor that regulates Golgi stress. Autophagy is disrupted in the hearts of these mice, which can be recapitulated by disrupting the Golgi. Systemic administration of modulators of autophagy or ER stress significantly delayed cardiac dysfunction and prolonged survival. These studies support a hypothesis wherein stress responses emanating from the perinuclear space contribute to the LMNA cardiomyopathy development.

Novel PIKfyve/Tubulin Dual-target Inhibitor as a Promising Therapeutic Strategy for B-cell Acute Lymphoblastic Leukemia

OBJECTIVE

In B-cell acute lymphoblastic leukemia (B-ALL), current intensive chemotherapies for adult patients fail to achieve durable responses in more than 50% of cases, underscoring the urgent need for new therapeutic regimens for this patient population. The present study aimed to determine whether HZX-02-059, a novel dual-target inhibitor targeting both phosphatidylinositol-3-phosphate 5-kinase (PIKfyve) and tubulin, is lethal to B-ALL cells and is a potential therapeutic for B-ALL patients.

METHODS

Cell proliferation, vacuolization, apoptosis, cell cycle, and in-vivo tumor growth were evaluated. In addition, Genome-wide RNA-sequencing studies were conducted to elucidate the mechanisms of action underlying the anti-leukemia activity of HZX-02-059 in B-ALL.

RESULTS

HZX-02-059 was found to inhibit cell proliferation, induce vacuolization, promote apoptosis, block the cell cycle, and reduce in-vivo tumor growth. Downregulation of the p53 pathway and suppression of the phosphoinositide 3-kinase (PI3K)/AKT pathway and the downstream transcription factors c-Myc and NF-κB were responsible for these observations.

CONCLUSION

Overall, these findings suggest that HZX-02-059 is a promising agent for the treatment of B-ALL patients resistant to conventional therapies.

Casein kinase 2 phosphorylates and induces the SALL2 tumor suppressor degradation in colon cancer cells

Spalt-like proteins are Zinc finger transcription factors from Caenorhabditis elegans to vertebrates, with critical roles in development. In vertebrates, four paralogues have been identified (SALL1-4), and SALL2 is the family's most dissimilar member. SALL2 is required during brain and eye development. It is downregulated in cancer and acts as a tumor suppressor, promoting cell cycle arrest and cell death. Despite its critical functions, information about SALL2 regulation is scarce. Public data indicate that SALL2 is ubiquitinated and phosphorylated in several residues along the protein, but the mechanisms, biological consequences, and enzymes responsible for these modifications remain unknown. Bioinformatic analyses identified several putative phosphorylation sites for Casein Kinase II (CK2) located within a highly conserved C-terminal PEST degradation motif of SALL2. CK2 is a serine/threonine kinase that promotes cell proliferation and survival and is often hyperactivated in cancer. We demonstrated that CK2 phosphorylates SALL2 residues S763, T778, S802, and S806 and promotes SALL2 degradation by the proteasome. Accordingly, pharmacological inhibition of CK2 with Silmitasertib (CX-4945) restored endogenous SALL2 protein levels in SALL2-deficient breast MDA-MB-231, lung H1299, and colon SW480 cancer cells. Silmitasertib induced a methuosis-like phenotype and cell death in SW480 cells. However, the phenotype was significantly attenuated in CRISPr/Cas9-mediated SALL2 knockout SW480 cells. Similarly, Sall2-deficient tumor organoids were more resistant to Silmitasertib-induced cell death, confirming that SALL2 sensitizes cancer cells to CK2 inhibition. We identified a novel CK2-dependent mechanism for SALL2 regulation and provided new insights into the interplay between these two proteins and their role in cell survival and proliferation.

Chemo-profiling of Purpureocillium lilacinum and Paecilomyces variotii isolates using GC-MS analysis, and evaluation of their metabolites against M. incognita

Nematophagous fungi are the best alternatives to chemical nematicides for managing nematodes considering environmental health. In the current study, activity of metabolites from ten isolates of Purpureocillium lilacinum (Thom) Luangsa-ard (Hypocreales: Ophiocordycipitaceae) and two isolates of Paecilomyces variotii Bainier (Eurotiales: Trichocomaceae), were examined to inhibit the hatching of Meloidogyne incognita (Kofoid & White) Chitwood (Tylenchida: Heteroderidae) eggs. At 100%, 50%, and 25% concentrations, respectively, the culture filtrate of the isolate P. lilacinum 6887 prevented 97.55%, 90.52%, and 62.97% of egg hatching. Out of all the isolates, Pl 6887, Pl 6553, and Pl 2362 showed the greatest results in the hatching inhibition experiment.Gas chromatography-mass spectrometry (GC-MS) analysis revealed a variety of nematicidal compounds from different isolates. A total of seven nematicidal compounds, including four very potent nematicidal fatty acids were found in the isolate Pl 6553. Secondary metabolites of the same isolate possess the highest M. incognita juvenile mortality, i.e., 43.33% and 92% after 48 hrs of treatment at 100 and 200 ppm concentrations, respectively. Significant difference was observed in juvenile mortality percentage among the isolate having highest and lowest nematicidal compounds. Nematicidal fatty acids like myristic and lauric acid were found for the first time in P. lilacinum. Multiple vacuole-like droplets were found inside the unhatched eggs inoculated with the culture filtrate of isolate Pl 6887, and also in the juveniles that perished in the ethyl acetate extract of isolate Pl 6553.

Rutin Linoleate Triggers Oxidative Stress-Mediated Cytoplasmic Vacuolation in Non-Small Cell Lung Cancer Cells

Lung cancer (LC) represents one of the most prevalent health issues globally and is a leading cause of tumor-related mortality. Despite being one the most attractive compounds of plant origin due to its numerous biological properties, the therapeutic applications of rutin (RUT) are limited by its disadvantageous pharmacokinetics. Thus, the present study aimed to evaluate in vitro the application of two RUT fatty acids bioconjugates, rutin oleate (RUT-O) and rutin linoleate (RUT-L), as potential improved RUT-based chemotherapeutics in non-small cell lung cancer (NSCLC) treatment. The results indicate that both compounds lacked cytotoxic potential in EpiAirway™ tissues at concentrations up to 125 µM. However, only RUT-L exerted anti-tumorigenic activity in NCI-H23 NSCLC cells after 24 h of treatment by reducing cell viability (up to 47%), proliferation, and neutral red uptake, causing cell membrane damage and lactate dehydrogenase (LDH) leakage, affecting cytoskeletal distribution, inducing cytoplasmic vacuolation, and increasing oxidative stress. The cytopathic effects triggered by RUT-L at 100 and 125 µM are indicators of a non-apoptotic cell death pathway that resembles the characteristics of paraptosis. The novel findings of this study stand as a basis for further investigations on the anti-cancer properties of RUT-L and their underlying mechanisms.

Discovery of Potent and Selective Phosphatidylinositol 3-Phosphate 5-Kinase (PIKfyve) Inhibitors as Methuosis Inducers

Cytoplasmic vacuolation-associated cell death, known as methuosis, offers a promising nonapoptotic approach for cancer treatment. In this study, we outline the synthesis and evaluation of potent methuosis-inducing compounds. These compounds selectively induce cell death, characterized by extensive cytoplasmic vacuolation in HeLa and MDA-MB-231 cells. Notably, compound L22 exhibited a remarkable interaction with PIKfyve kinase, boasting a Kd value of 0.47 nM, surpassing the positive controls D-13 and MOMIPP in potency. Furthermore, it is important to highlight that cell death induced by compound L22 is unequivocally attributed to methuosis as it differs from apoptosis, necrosis, or autophagy. Importantly, when administered orally, L22 effectively inhibited tumor growth in a HeLa xenograft model without any apparent signs of toxicity. These results underscore the potential of L22 as a valuable tool for in-depth investigations into the mechanisms of methuosis and as a promising lead compound to guide structural optimization.

The Mechanisms of Regulated Cell Death: Structural and Functional Proteomic Pathways Induced or Inhibited by a Specific Protein-A Narrative Review

Billions of cells die in us every hour, and our tissues do not shrink because there is a natural regulation where Cell Death (CD) is balanced with cell division. The process in which cells eliminate themselves in a controlled manner is called Programmed Cell Death (PCD). The PCD plays an important role during embryonic development, in maintaining homeostasis of the body's tissues, and in the elimination of damaged cells, under a wide range of physiological and developmental stimuli. A multitude of protein mediators of PCD have been identified and signals have been found to utilize common pathways elucidating the proteins involved. This narrative review focuses on caspase-dependent and caspase-independent PCD pathways. Included are studies of caspase-dependent PCD such as Anoikis, Catastrophe Mitotic, Pyroptosis, Emperitosis, Parthanatos and Cornification, and Caspase-Independent PCD as Wallerian Degeneration, Ferroptosis, Paraptosis, Entosis, Methuosis, and Extracellular Trap Abnormal Condition (ETosis), as well as neutrophil extracellular trap abnormal condition (NETosis) and Eosinophil Extracellular Trap Abnormal Condition (EETosis). Understanding PCD from those reported in this review could shed substantial light on the processes of biological homeostasis. In addition, identifying specific proteins involved in these processes is mandatory to identify molecular biomarkers, as well as therapeutic targets. This knowledge could provide the ability to modulate the PCD response and could lead to new therapeutic interventions in a wide range of diseases.

Infection of tumor cells with Salmonella typhimurium mimics immunogenic cell death and elicits tumor-specific immune responses

Some properties of Salmonella-infected cells overlap with immunogenic cell death. In this study, we demonstrated that intracellular infection of melanoma with Salmonella typhimurium induced high immunogenicity in melanoma cells, leading to antitumor effects with melanoma-antigen-specific T-cell responses. Murine B16F10 melanoma cells were infected with tdTomato-expressing attenuated S. typhimurium (VNP20009; VNP-tdT), triggering massive cell vacuolization. VNP-tdT-infected B16F10 cells were phagocytosed efficiently, which induced the activation of antigen-presenting cells with CD86 expression in vitro. Subcutaneous coimplantation of uninfected and VNP-tdT-infected B16F10 cells into C57BL/6 mice significantly suppressed tumor growth compared with the implantation of uninfected B16F10 cells alone. Inoculation of mice with VNP-tdT-infected B16F10 cells elicited the proliferation of melanoma-antigen (gp100)-specific T cells, and it protected the mice from the second tumor challenge of uninfected B16F10 cells. These results suggest that Salmonella-infected tumor cells acquire effective adjuvanticity, leading to ideal antitumor immune responses.

Ferroptosis, Metabolic Rewiring, and Endometrial Cancer

Ferroptosis is a newly discovered form of regulated cell death. The main feature of ferroptosis is excessive membrane lipid peroxidation caused by iron-mediated chemical and enzymatic reactions. In normal cells, harmful lipid peroxides are neutralized by glutathione peroxidase 4 (GPX4). When GPX4 is inhibited, ferroptosis occurs. In mammalian cells, ferroptosis serves as a tumor suppression mechanism. Not surprisingly, in recent years, ferroptosis induction has gained attention as a potential anticancer strategy, alone or in combination with other conventional therapies. However, sensitivity to ferroptosis inducers depends on the metabolic state of the cell. Endometrial cancer (EC) is the sixth most common cancer in the world, with more than 66,000 new cases diagnosed every year. Out of all gynecological cancers, carcinogenesis of EC is mostly dependent on metabolic abnormalities. Changes in the uptake and catabolism of iron, lipids, glucose, and glutamine affect the redox capacity of EC cells and, consequently, their sensitivity to ferroptosis-inducing agents. In addition to this, in EC cells, ferroptosis-related genes are usually mutated and overexpressed, which makes ferroptosis a promising target for EC prediction, diagnosis, and therapy. However, for a successful application of ferroptosis, the connection between metabolic rewiring and ferroptosis in EC needs to be deciphered, which is the focus of this review.

Cell death classification: A new insight based on molecular mechanisms

Cells tend to disintegrate themselves or are forced to undergo such destructive processes in critical circumstances. This complex cellular function necessitates various mechanisms and molecular pathways in order to be executed. The very nature of cell death is essentially important and vital for maintaining homeostasis, thus any type of disturbing occurrence might lead to different sorts of diseases and dysfunctions. Cell death has various modalities and yet, every now and then, a new type of this elegant procedure gets to be discovered. The diversity of cell death compels the need for a universal organizing system in order to facilitate further studies, therapeutic strategies and the invention of new methods of research. Considering all that, we attempted to review most of the known cell death mechanisms and sort them all into one arranging system that operates under a simple but subtle decision-making (If \ Else) order as a sorting algorithm, in which it decides to place and sort an input data (a type of cell death) into its proper set, then a subset and finally a group of cell death. By proposing this algorithm, the authors hope it may solve the problems regarding newer and/or undiscovered types of cell death and facilitate research and therapeutic applications of cell death.

Nutlin-3a induces KRAS mutant/p53 wild type lung cancer specific methuosis-like cell death that is dependent on GFPT2

BACKGROUND

Oncogenic KRAS mutation, the most frequent mutation in non-small cell lung cancer (NSCLC), is an aggressiveness risk factor and leads to the metabolic reprogramming of cancer cells by promoting glucose, glutamine, and fatty acid absorption and glycolysis. Lately, sotorasib was approved by the FDA as a first-in-class KRAS-G12C inhibitor. However, sotorasib still has a derivative barrier, which is not effective for other KRAS mutation types, except for G12C. Additionally, resistance to sotorasib is likely to develop, demanding the need for alternative therapeutic strategies.

METHODS

KRAS mutant, and wildtype NSCLC cells were used in vitro cell analyses. Cell viability, proliferation, and death were measured by MTT, cell counting, colony analyses, and annexin V staining for FACS. Cell tracker dyes were used to investigate cell morphology, which was examined by holotomograpy, and confocal microscopes. RNA sequencing was performed to identify key target molecule or pathway, which was confirmed by qRT-PCR, western blotting, and metabolite analyses by UHPLC-MS/MS. Zebrafish and mouse xenograft model were used for in vivo analysis.

RESULTS

In this study, we found that nutlin-3a, an MDM2 antagonist, inhibited the KRAS-PI3K/Akt-mTOR pathway and disrupted the fusion of both autophagosomes and macropinosomes with lysosomes. This further elucidated non-apoptotic and catastrophic macropinocytosis associated methuosis-like cell death, which was found to be dependent on GFPT2 of the hexosamine biosynthetic pathway, specifically in KRAS mutant /p53 wild type NSCLC cells.

CONCLUSION

These results indicate the potential of nutlin-3a as an alternative agent for treating KRAS mutant/p53 wild type NSCLC cells.

Paradigm Shift in Gastric Cancer Prevention: Harnessing the Potential of Aristolochia olivieri Extract

Gastric cancer, particularly adenocarcinoma, is a significant global health concern. Environmental risk factors, such as Helicobacter pylori infection and diet, play a role in its development. This study aimed to characterize the chemical composition and evaluate the in vitro antibacterial and antitumor activities of an Aristolochia olivieri Colleg. ex Boiss. Leaves' methanolic extract (AOME). Additionally, morphological changes in gastric cancer cell lines were analyzed. AOME was analyzed using HPLC-MS/MS, and its antibacterial activity against H. pylori was assessed using the broth microdilution method. MIC and MBC values were determined, and positive and negative controls were included in the evaluation. Anticancer effects were assessed through in vitro experiments using AGS, KATO-III, and SNU-1 cancer cell lines. The morphological changes were examined through SEM and TEM analyses. AOME contained several compounds, including caffeic acid, rutin, and hyperoside. The extract displayed significant antimicrobial effects against H. pylori, with consistent MIC and MBC values of 3.70 ± 0.09 mg/mL. AOME reduced cell viability in all gastric cancer cells in a dose- and time-dependent manner. Morphological analyses revealed significant ultrastructural changes in all tumor cell lines, suggesting the occurrence of cellular apoptosis. This study demonstrated that AOME possesses antimicrobial activity against H. pylori and potent antineoplastic properties in gastric cancer cell lines. AOME holds promise as a natural resource for innovative nutraceutical approaches in gastric cancer management. Further research and in vivo studies are warranted to validate its potential clinical applications.

The Genetic Background of Abnormalities in Metabolic Pathways of Phosphoinositides and Their Linkage with the Myotubular Myopathies, Neurodegenerative Disorders, and Carcinogenesis

Myo-inositol belongs to one of the sugar alcohol groups known as cyclitols. Phosphatidylinositols are one of the derivatives of Myo-inositol, and constitute important mediators in many intracellular processes such as cell growth, cell differentiation, receptor recycling, cytoskeletal organization, and membrane fusion. They also have even more functions that are essential for cell survival. Mutations in genes encoding phosphatidylinositols and their derivatives can lead to many disorders. This review aims to perform an in-depth analysis of these connections. Many authors emphasize the significant influence of phosphatidylinositols and phosphatidylinositols' phosphates in the pathogenesis of myotubular myopathies, neurodegenerative disorders, carcinogenesis, and other less frequently observed diseases. In our review, we have focused on three of the most often mentioned groups of disorders. Inositols are the topic of many studies, and yet, there are no clear results of successful clinical trials. Analysis of the available literature gives promising results and shows that further research is still needed.

Lipid polymer hybrid nanoparticles: a custom-tailored next-generation approach for cancer therapeutics

Lipid-based polymeric nanoparticles are the highly popular carrier systems for cancer drug therapy. But presently, detailed investigations have revealed their flaws as drug delivery carriers. Lipid polymer hybrid nanoparticles (LPHNPs) are advanced core-shell nanoconstructs with a polymeric core region enclosed by a lipidic layer, presumed to be derived from both liposomes and polymeric nanounits. This unique concept is of utmost importance as a combinable drug delivery platform in oncology due to its dual structured character. To add advantage and restrict one's limitation by other, LPHNPs have been designed so to gain number of advantages such as stability, high loading of cargo, increased biocompatibility, rate-limiting controlled release, and elevated drug half-lives as well as therapeutic effectiveness while minimizing their drawbacks. The outer shell, in particular, can be functionalized in a variety of ways with stimuli-responsive moieties and ligands to provide intelligent holding and for active targeting of antineoplastic medicines, transport of genes, and theragnostic. This review comprehensively provides insight into recent substantial advancements in developing strategies for treating various cancer using LPHNPs. The bioactivity assessment factors have also been highlighted with a discussion of LPHNPs future clinical prospects.

Progress in the discovery and development of small molecule methuosis inducers

Current cancer chemotherapies rely mainly on the induction of apoptosis of tumor cells, while drug resistance arising from conventional chemicals has always been a big challenge. In recent years, more and more new types of cell deaths including methuosis have been extensively investigated and recognized as potential alternative targets for future cancer treatment. Methuosis is usually caused by excessive accumulation of macropinosomes owing to ectopic activation of macropinocytosis, which can be triggered by external stimuli such as chemical agents. Increasing reports demonstrate that many small molecule compounds could specifically induce methuosis in tumor cells while showing little or no effect on normal cells. This finding raises the possibility of targeting tumor cell methuosis as an effective strategy for the prevention of cancer. Based on fast-growing studies lately, we herein provide a comprehensive overview on the overall research progress of small molecule methuosis inducers. Promisingly, previous efforts and experiences will facilitate the development of next-generation anticancer therapies.

Diversity and complexity of cell death: a historical review

Death is the inevitable fate of all living organisms, whether at the individual or cellular level. For a long time, cell death was believed to be an undesirable but unavoidable final outcome of nonfunctioning cells, as inflammation was inevitably triggered in response to damage. However, experimental evidence accumulated over the past few decades has revealed different types of cell death that are genetically programmed to eliminate unnecessary or severely damaged cells that may damage surrounding tissues. Several types of cell death, including apoptosis, necrosis, autophagic cell death, and lysosomal cell death, which are classified as programmed cell death, and pyroptosis, necroptosis, and NETosis, which are classified as inflammatory cell death, have been described over the years. Recently, several novel forms of cell death, namely, mitoptosis, paraptosis, immunogenic cell death, entosis, methuosis, parthanatos, ferroptosis, autosis, alkaliptosis, oxeiptosis, cuproptosis, and erebosis, have been discovered and advanced our understanding of cell death and its complexity. In this review, we provide a historical overview of the discovery and characterization of different forms of cell death and highlight their diversity and complexity. We also briefly discuss the regulatory mechanisms underlying each type of cell death and the implications of cell death in various physiological and pathological contexts. This review provides a comprehensive understanding of different mechanisms of cell death that can be leveraged to develop novel therapeutic strategies for various diseases.

Investigating ionizing radiation-induced changes in breast cancer cells using stimulated Raman scattering microscopy

Significance

Altered lipid metabolism of cancer cells has been implicated in increased radiation resistance. A better understanding of this phenomenon may lead to improved radiation treatment planning. Stimulated Raman scattering (SRS) microscopy enables label-free and quantitative imaging of cellular lipids but has never been applied in this domain.

Aim

We sought to investigate the radiobiological response in human breast cancer MCF7 cells using SRS microscopy, focusing on how radiation affects lipid droplet (LD) distribution and cellular morphology.

Approach

MCF7 breast cancer cells were exposed to either 0 or 30 Gy (X-ray) ionizing radiation and imaged using a spectrally focused SRS microscope every 24 hrs over a 72-hr time period. Images were analyzed to quantify changes in LD area per cell, lipid and protein content per cell, and cellular morphology. Cell viability and confluency were measured using a live cell imaging system while radiation-induced lipid peroxidation was assessed using BODIPY C11 staining and flow cytometry.

Results

The LD area per cell and total lipid and protein intensities per cell were found to increase significantly for irradiated cells compared to control cells from 48 to 72 hrs post irradiation. Increased cell size, vacuole formation, and multinucleation were observed as well. No significant cell death was observed due to irradiation, but lipid peroxidation was found to be greater in the irradiated cells than control cells at 72 hrs.

Conclusions

This pilot study demonstrates the potential of SRS imaging for investigating ionizing radiation-induced changes in cancer cells without the use of fluorescent labels.

V-ATPase V0 subunit activation mediates maduramicin-induced methuosis through blocking endolysosomal trafficking in vitro and in vivo

Methuosis, a novel cell death phenotype, is characterized by accumulation of cytoplasmic vacuolization upon external stimulus. Methuosis plays a critical role in maduramicin-induced cardiotoxicity despite the underlying mechanism is largely unknown. Herein, we aimed to investigate the origin and intracellular trafficking of cytoplasmic vacuoles, as well as the molecular mechanism of methuosis caused by maduramicin (1 μg/mL) in myocardial cells. H9c2 cells and broiler chicken were used and were exposed to maduramicin at doses of 1 μg/mL in vitro and 5 ppm-30 ppm in vivo. Morphological observation and dextran-Alexa Fluor 488 tracer experiment showed that endosomal compartments swelling and excessive macropinocytosis contributed to madurdamcin-induced methuosis. Cell counting kit-8 assay and morphology indicated pharmacological inhibition of macropinocytosis largely prevent H9c2 cells from maduramicin-triggered methuosis. In addition, late endosomal marker Rab7 and lysosomal associated membrane protein 1 (LAMP1) increased in a time-dependent manner after maduramicin treatment, and the recycling endosome marker Rab11 and ADP-ribosylation factor 6 (Arf6) were decreased by maduramicin. Vacuolar-H⁺-ATPase (V-ATPase) was activated by maduramicin, and pharmacological inhibition and genetic knockdown V0 subunit of V-ATPase restore endosomal-lysosomal trafficking and prevent H9c2 cells methuosis. Animal experiment showed that severe cardiac injury included the increase of creatine kinase (CK) and creatine kinase-MB (CK-MB), and vacuolar degeneration resembled methuosis in vivo after maduramicin treatment. Taken together, these findings demonstrate that targeting the inhibition of V-ATPase V0 subunit will prevent myocardial cells methuosis by restoring endosomal-lysosomal trafficking.

V. J, Pal S, Nair BG, Kar R, Mishra N. Paraptosis: a unique cell death mode for targeting cancer

Programmed cell death (PCD) is the universal process that maintains cellular homeostasis and regulates all living systems' development, health and disease. Out of all, apoptosis is one of the major PCDs that was found to play a crucial role in many disease conditions, including cancer. The cancer cells acquire the ability to escape apoptotic cell death, thereby increasing their resistance towards current therapies. This issue has led to the need to search for alternate forms of programmed cell death mechanisms. Paraptosis is an alternative cell death pathway characterized by vacuolation and damage to the endoplasmic reticulum and mitochondria. Many natural compounds and metallic complexes have been reported to induce paraptosis in cancer cell lines. Since the morphological and biochemical features of paraptosis are much different from apoptosis and other alternate PCDs, it is crucial to understand the different modulators governing it. In this review, we have highlighted the factors that trigger paraptosis and the role of specific modulators in mediating this alternative cell death pathway. Recent findings include the role of paraptosis in inducing anti-tumour T-cell immunity and other immunogenic responses against cancer. A significant role played by paraptosis in cancer has also scaled its importance in knowing its mechanism. The study of paraptosis in xenograft mice, zebrafish model, 3D cultures, and novel paraptosis-based prognostic model for low-grade glioma patients have led to the broad aspect and its potential involvement in the field of cancer therapy. The co-occurrence of different modes of cell death with photodynamic therapy and other combinatorial treatments in the tumour microenvironment are also summarized here. Finally, the growth, challenges, and future perspectives of paraptosis research in cancer are discussed in this review. Understanding this unique PCD pathway would help to develop potential therapy and combat chemo-resistance in various cancer.

p53 controls choice between apoptotic and non-apoptotic death following DNA damage

DNA damage can activate apoptotic and non-apoptotic forms of cell death; however, it remains unclear what features dictate which type of cell death is activated. We report that p53 controls the choice between apoptotic and non-apoptotic death following exposure to DNA damage. In contrast to the conventional model, which suggests that p53-deficient cells should be resistant to DNA damage-induced cell death, we find that p53-deficient cells die at high rates following DNA damage, but exclusively using non-apoptotic mechanisms. Our experimental data and computational modeling reveal that non-apoptotic death in p53-deficient cells has not been observed due to use of assays that are either insensitive to cell death, or that specifically score apoptotic cells. Using functional genetic screening - with an analysis that enables computational inference of the drug-induced death rate - we find in p53-deficient cells that DNA damage activates a mitochondrial respiration-dependent form of cell death, called MPT-driven necrosis. Cells deficient for p53 have high basal respiration, which primes MPT-driven necrosis. Finally, using metabolite profiling, we identified mitochondrial activity-dependent metabolic vulnerabilities that can be targeted to potentiate the lethality of DNA damage specifically in p53-deficient cells. Our findings reveal how the dual functions of p53 in regulating mitochondrial activity and the DNA damage response combine to facilitate the choice between apoptotic and non-apoptotic death.

Exploring the anticancer activity and the mechanism of action of pyrrolomycins F obtained by microwave-assisted total synthesis

Pyrrolomycins (PMs) are a family of naturally occurring antibiotic agents, isolated from the fermentation broth of Actinosporangium and Streptomyces species. Pursuing our studies on pyrrolomycins, we performed the total synthesis of the F-series pyrrolomycins (1-4) by microwave-assisted synthesis (MAOS), thus obtaining the title compounds in excellent yields (63-69%). Considering that there is no evidence so far of the anticancer effect of this class of compounds, we investigated PMs for their antiproliferative activity against HCT116 and MCF-7 cancer cell lines. PMs showed anticancer activity at submicromolar level with a minimal effect on normal epithelial cell line (hTERT RPE-1), and they were able to induce several morphological changes including elongated cells, cytoplasm vacuolization, long and thin filopodia as well as the appearance of tunneling nanotubes (TNTs). These data suggest that PMs could act by impairing the cell membranes and the cytoskeleton organization, with subsequent increase of ROS generation and the activation of different forms of non-apoptotic cell death.

Tubeimoside-2 Triggers Methuosis in Hepatocarcinoma Cells through the MKK4-p38α Axis

Liver cancer, consisting mainly of hepatocellular carcinoma, is the third leading cause of cancer-related mortality worldwide. Despite advances in targeted therapies, these approaches remain insufficient in meeting the pressing clinical demands. Here, we present a novel alternative that calls for a non-apoptotic program to solve the current dilemma. Specifically, we identified that tubeimoside 2 (TBM-2) could induce methuosis in hepatocellular carcinoma cells, a recently recognized mode of cell death characterized by pronounced vacuolization, necrosis-like membrane disruption, and no response to caspase inhibitors. Further proteomic analysis revealed that TBM-2-driven methuosis is facilitated by the hyperactivation of the MKK4-p38α axis and the boosted lipid metabolism, especially cholesterol biosynthesis. Pharmacological interventions targeting either the MKK4-p38α axis or cholesterol biosynthesis effectively suppress TBM-2-induced methuosis, highlighting the pivotal role of these mechanisms in TBM-2-mediated cell death. Moreover, TBM-2 treatment effectively suppressed tumor growth by inducing methuosis in a xenograft mouse model of hepatocellular carcinoma. Taken together, our findings provide compelling evidence of TBM-2's remarkable tumor-killing effects by inducing methuosis, both in vitro and in vivo. TBM-2 represents a promising avenue for the development of innovative and effective therapies for hepatocellular carcinoma, one that may ultimately offer significant clinical benefits for patients with this devastating disease.