EMT-related protein expression in polyploid giant cancer cells and their daughter cells with different passages after triptolide treatment

Oncogenic signaling in the Drosophila prostate-like accessory gland activates a pro-tumorigenic program in the absence of proliferation

Drosophila models for tumorigenesis have revealed conserved mechanisms of signaling involved in mammalian cancer. Many of these models use highly mitotically active Drosophila tissues. Few Drosophila tumorigenesis models use adult tissues, when most cells are terminally differentiated and postmitotic. The Drosophila accessory glands are prostate-like tissues, and a model for prostate tumorigenesis using this tissue has been explored. In this prior model, oncogenic signaling was induced during the proliferative stages of accessory gland development, raising the question of how oncogenic activity impacts the terminally differentiated, postmitotic adult tissue. Here, we show that oncogenic signaling in the adult Drosophila accessory gland leads to activation of a conserved pro-tumorigenic program, similar to that of mitotic tissues, but in the absence of proliferation. In our experiments, oncogenic signaling in the adult gland led to tissue hypertrophy with nuclear anaplasia, in part through endoreduplication. Oncogene-induced gene expression changes in the adult Drosophila prostate-like model overlapped with those in polyploid prostate cancer cells after chemotherapy, which potentially mediate tumor recurrence. Thus, the adult accessory glands provide a useful model for aspects of prostate cancer progression that lack cellular proliferation.

High-Throughput Empirical and Virtual Screening To Discover Novel Inhibitors of Polyploid Giant Cancer Cells in Breast Cancer

Therapy resistance in breast cancer is increasingly attributed to polyploid giant cancer cells (PGCCs), which arise through whole genome doubling and exhibit heightened resilience to standard treatments. Characterized by enlarged nuclei and increased DNA content, these cells tend to be dormant under therapeutic stress, driving disease relapse. Despite their critical role in resistance, strategies to effectively target PGCCs are limited, largely due to the lack of high-throughput methods for assessing their viability. Traditional assays lack the sensitivity needed to detect PGCC-specific elimination, prompting the development of novel approaches. To address this challenge, we developed a high-throughput single-cell morphological analysis workflow designed to differentiate compounds that selectively inhibit non-PGCCs, PGCCs, or both. Using this method, we screened a library of 2726 FDA Phase 1-approved drugs, identifying promising anti-PGCC candidates, including proteasome inhibitors, FOXM1, CHK, and macrocyclic lactones. Notably, RNA-Seq analysis of cells treated with the macrocyclic lactone Pyronaridine revealed AXL inhibition as a potential strategy for targeting PGCCs. Although our single-cell morphological analysis pipeline is powerful, empirical testing of all existing compounds is impractical and inefficient. To overcome this limitation, we trained a machine learning model to predict anti-PGCC efficacy in silico, integrating chemical fingerprints and compound descriptions from prior publications and databases. The model demonstrated a high correlation with experimental outcomes and predicted efficacious compounds in an expanded library of over 6,000 drugs. Among the top-ranked predictions, we experimentally validated five compounds as potent PGCC inhibitors using cell lines and patient-derived models. These findings underscore the synergistic potential of integrating high-throughput empirical screening with machine learning-based virtual screening to accelerate the discovery of novel therapies, particularly for targeting therapy-resistant PGCCs in breast cancer.

Triptolide exhibits dual anti-tumor effects through inhibiting autophagy and extracellular matrix activation in pancreatic cancer

AIM

The tumor microenvironment in pancreatic cancer, characterized by abundant desmoplastic stroma, has been implicated in the failure of chemotherapy. Therefore, developing therapeutic strategies targeting tumor and stromal cells is essential. Triptolide, a natural compound derived from the plant Tripterygium wilfordii, has shown antitumor activity in various cancers, including pancreatic cancer. However, its effects on pancreatic cancer cells and the microenvironment remain unclear. This study aimed to explore the effect of triptolide on tumor cells and the tumor microenvironment in pancreatic cancer.

METHODS

Cell Counting Kit-8, colony formation, apoptosis, and cell cycle assays were performed to determine the effect of triptolide on tumor cells. Additionally, co-culture assays were performed to explore the effects of the compound on cancer-associated fibroblasts (CAFs) in vitro. Orthotopic xenograft and subcutaneous tumor models were used to explore the antitumor and antistromal activation effects of triptolide in vivo. RNA sequencing was performed to identify the pathways involved in these processes in pancreatic cancer cells.

RESULTS

Triptolide inhibited the proliferation of pancreatic cancer cells and attenuated stromal activation in vitro and in vivo. Furthermore, it suppressed autophagy and induced apoptosis in pancreatic cancer cells by inhibiting the secretion of CXCL1. Extracellular matrix formation in CAFs was disrupted by suppressing the paracrine secretion of TGF-β from tumor cells.

CONCLUSION

These findings indicate that triptolide plays a dual antitumor role against tumor cells and CAFs, thus providing new insights into treating pancreatic cancer in the future.

Potential antitumor activity of triptolide and its derivatives: Focused on gynecological and breast cancers

Cancer remains one of the greatest global health concerns. This is especially true for gynecological cancers, which include cervical, ovarian, and endometrial cancers, and breast cancer. Natural products used for cancer treatment offer some unique advantages. Triptolide (TPL) is a biologically active terpenoid extracted from Tripterygium wilfordii, which exhibits anti-inflammatory, immunosuppressive, antitumor, and other pharmacological activities. However, clinical applications of TPL are restricted because of poor water solubility and severe cytotoxicity; to overcome these limitations, various TPL derivatives and drug delivery systems, especially nanocarriers, have been used. Furthermore, various preclinical and clinical studies have demonstrated that TPL and its derivatives exhibit excellent antitumor effects by targeting proteins involved in multiple signaling pathways. Here, we review the progress regarding novel drug delivery systems, antitumor activities, and molecular mechanisms of action of TPL and its derivatives against gynecological and breast cancers. TPL and its derivatives inhibit tumor growth, suppress tumor metastasis, and enhance the drug sensitization of resistant cancers. In addition, TPL and its derivatives exert synergistic antitumor effects against gynecological and breast cancers when combined with existing antitumor drugs, such as carboplatin, cisplatin, and PI3K inhibitors. Moreover, we highlight the clinical potential of TPL analogs against cancer from bench to bedside and their prospects for future applications in gynecologic and breast cancers.

Emerging Paradigms in Cancer Metastasis: Ghost Mitochondria, Vasculogenic Mimicry, and Polyploid Giant Cancer Cells

The capacity of cancer cells to migrate from a primary tumor, disseminate throughout the body, and eventually establish secondary tumors is a fundamental aspect of metastasis. A detailed understanding of the cellular and molecular mechanisms underpinning this multifaceted process would facilitate the rational development of therapies aimed at treating metastatic disease. Although various hypotheses and models have been proposed, no single concept fully explains the mechanism of metastasis or integrates all observations and experimental findings. Recent advancements in metastasis research have refined existing theories and introduced new ones. This review evaluates several novel/emerging theories, focusing on ghost mitochondria (GM), vasculogenic mimicry (VM), and polyploid giant cancer cells (PGCCs).

High-Throughput Empirical and Virtual Screening to Discover Novel Inhibitors of Polyploid Giant Cancer Cells in Breast Cancer

Therapy resistance in breast cancer is increasingly attributed to polyploid giant cancer cells (PGCCs), which arise through whole-genome doubling and exhibit heightened resilience to standard treatments. Characterized by enlarged nuclei and increased DNA content, these cells tend to be dormant under therapeutic stress, driving disease relapse. Despite their critical role in resistance, strategies to effectively target PGCCs are limited, largely due to the lack of high-throughput methods for assessing their viability. Traditional assays lack the sensitivity needed to detect PGCC-specific elimination, prompting the development of novel approaches. To address this challenge, we developed a high-throughput single-cell morphological analysis workflow designed to differentiate compounds that selectively inhibit non-PGCCs, PGCCs, or both. Using this method, we screened a library of 2,726 FDA Phase 1-approved drugs, identifying promising anti-PGCC candidates, including proteasome inhibitors, FOXM1, CHK, and macrocyclic lactones. Notably, RNA-Seq analysis of cells treated with the macrocyclic lactone Pyronaridine revealed AXL inhibition as a potential strategy for targeting PGCCs. Although our single-cell morphological analysis pipeline is powerful, empirically testing all existing compounds is impractical and inefficient. To overcome this limitation, we trained a machine learning model to predict anti-PGCC efficacy in silico, integrating chemical fingerprints and compound descriptions from prior publications and databases. The model demonstrated a high correlation with experimental outcomes and predicted efficacious compounds in an expanded library of over 6,000 drugs. Among the top-ranked predictions, we experimentally validated two compounds as potent PGCC inhibitors. These findings underscore the synergistic potential of integrating high-throughput empirical screening with machine learning-based virtual screening to accelerate the discovery of novel therapies, particularly for targeting therapy-resistant PGCCs in breast cancer.

A Fungicide, Fludioxonil, Formed the Polyploid Giant Cancer Cells and Induced Metastasis and Stemness in MDA-MB-231 Triple-Negative Breast Cancer Cells

Fludioxonil, an antifungal agent used as a pesticide, leaves a measurable residue in fruits and vegetables. It has been identified to cause endocrine disruption, interrupt normal development, and cause various diseases such as cancers. In this study, fludioxonil was examined for its effects on the development and metastasis of breast cancer cells. On fludioxonil exposure (10-5 M) for 72 h, mutant p53 (mutp53) MDA-MB-231 triple-negative breast cancer (TNBC) cells significantly inhibited cell viability and developed into polyploid giant cancer cells (PGCCs), with an increase in the number of nuclei and expansion in the cell body size. Fludioxonil exposure disrupted the normal cell cycle phase ratio, resulting in a new peak. In addition, PGCCs showed greater motility than the control and were resistant to anticancer drugs, i.e., doxorubicin, cisplatin, and 5-fluorouracil. Cyclin E1, nuclear factor kappa B (NF-κB), and p53 expressions were remarkably increased, and the expression of cell cycle-, epithelial-mesenchymal-transition (EMT)-, and cancer stemness-related proteins were increased in the PGCCs. The daughter cells obtained from PGCCs had the single nucleus but maintained their enlarged cell size and showed greater cell migration ability and resistance to the anticancer agents. Consequently, fludioxonil accumulated Cyclin E1 and promoted the inflammatory cytokine-enriched microenvironment through the up-regulation of TNF and NF-κB which led to the transformation to PGCCs via abnormal cell cycles such as mitotic delay and mitotic slippage in mutp53 TNBC MDA-MB-231 cells. PGCCs and their daughter cells exhibited significant migration ability, chemo-resistance, and cancer stemness. These results strongly suggest that fludioxonil, as an inducer of potential genotoxicity, may induce the formation of PGCCs, leading to the formation of metastatic and stem cell-like breast cancer cells.

Oncogenic signaling in the adult Drosophila prostate-like accessory gland leads to activation of a conserved pro-tumorigenic program, in the absence of proliferation

Drosophila models for tumorigenesis and metastasis have revealed conserved mechanisms of signaling that are also involved in mammalian cancer. Many of these models use the proliferating tissues of the larval stages of Drosophila development, when tissues are highly mitotically active, or stem cells are abundant. Fewer Drosophila tumorigenesis models use adult animals to initiate tumor formation when many tissues are largely terminally differentiated and postmitotic. The Drosophila accessory glands are prostate-like tissues and a model for some aspects of prostate tumorigenesis using this tissue has been explored. In this model, oncogenic signaling was induced during the proliferative stage of accessory gland development, raising the question of how oncogenic activity would impact the terminally differentiated and postmitotic adult tissue. Here, we show that oncogenic signaling in the adult Drosophila accessory gland leads to activation of a conserved pro-tumorigenic program, similar to that observed in mitotic larval tissues, but in the absence of proliferation. Oncogenic signaling in the adult postmitotic gland leads to tissue hyperplasia with nuclear anaplasia and aneuploidy through endoreduplication, which increases polyploidy and occasionally results in non-mitotic neoplastic-like extrusions. We compare gene expression changes in our Drosophila model with that of endocycling prostate cancer cells induced by chemotherapy, which potentially mediate tumor recurrence after treatment. Similar signaling pathways are activated in the Drosophila gland and endocycling cancer cells, suggesting the adult accessory glands provide a useful model for aspects of prostate cancer progression that do not involve cellular proliferation.

Characterization of polyploidy in cancer: Current status and future perspectives

Various cancers frequently exhibit polyploidy, observed in a condition where a cell possesses more than two sets of chromosomes, which is considered a hallmark of the disease. The state of polyploidy often leads to aneuploidy, where cells possess an abnormal number or structure of chromosomes. Recent studies suggest that oncogenes contribute to aneuploidy. This finding significantly underscores its impact on cancer. Cancer cells exposed to certain chemotherapeutic drugs tend to exhibit an increased incidence of polyploidy. This occurrence is strongly associated with several challenges in cancer treatment, including metastasis, resistance to chemotherapy and the recurrence of malignant tumors. Indeed, it poses a significant hurdle to achieve complete tumor eradication and effective cancer therapy. Recently, there has been a growing interest in the field of polyploidy related to cancer for developing effective anti-cancer therapies. Polyploid cancer cells confer both advantages and disadvantages to tumor pathogenicity. This review delineates the diverse characteristics of polyploid cells, elucidates the pivotal role of polyploidy in cancer, and explores the advantages and disadvantages it imparts to cancer cells, along with the current approaches tried in lab settings to target polyploid cells. Additionally, it considers experimental strategies aimed at addressing the outstanding questions within the realm of polyploidy in relation to cancer.

Premature endocycling of Drosophila follicle cells causes pleiotropic defects in oogenesis

Endocycling cells grow and repeatedly duplicate their genome without dividing. Cells switch from mitotic cycles to endocycles in response to developmental signals during the growth of specific tissues in a wide range of organisms. The purpose of switching to endocycles, however, remains unclear in many tissues. Additionally, cells can switch to endocycles in response to conditional signals, which can have beneficial or pathological effects on tissues. However, the impact of these unscheduled endocycles on development is underexplored. Here, we use Drosophila ovarian somatic follicle cells as a model to examine the impact of unscheduled endocycles on tissue growth and function. Follicle cells normally switch to endocycles at mid-oogenesis. Inducing follicle cells to prematurely switch to endocycles resulted in the lethality of the resulting embryos. Analysis of ovaries with premature follicle cell endocycles revealed aberrant follicular epithelial structure and pleiotropic defects in oocyte growth, developmental gene amplification, and the migration of a special set of follicle cells known as border cells. Overall, these findings reveal how unscheduled endocycles can disrupt tissue growth and function to cause aberrant development.

Dormant cancer cells and polyploid giant cancer cells: The roots of cancer recurrence and metastasis

Tumour cell dormancy is critical for metastasis and resistance to chemoradiotherapy. Polyploid giant cancer cells (PGCCs) with giant or multiple nuclei and high DNA content have the properties of cancer stem cell and single PGCCs can individually generate tumours in immunodeficient mice. PGCCs represent a dormant form of cancer cells that survive harsh tumour conditions and contribute to tumour recurrence. Hypoxic mimics, chemotherapeutics, radiation and cytotoxic traditional Chinese medicines can induce PGCCs formation through endoreduplication and/or cell fusion. After incubation, dormant PGCCs can recover from the treatment and produce daughter cells with strong proliferative, migratory and invasive abilities via asymmetric cell division. Additionally, PGCCs can resist hypoxia or chemical stress and have a distinct protein signature that involves chromatin remodelling and cell cycle regulation. Dormant PGCCs form the cellular basis for therapeutic resistance, metastatic cascade and disease recurrence. This review summarises regulatory mechanisms governing dormant cancer cells entry and exit of dormancy, which may be used by PGCCs, and potential therapeutic strategies for targeting PGCCs.

Premature endocycling of Drosophila follicle cells causes pleiotropic defects in oogenesis

Endocycling cells grow and repeatedly duplicate their genome without dividing. Cells switch from mitotic cycles to endocycles in response to developmental signals during the growth of specific tissues in a wide range of organisms. The purpose of switching to endocycles, however, remains unclear in many tissues. Additionally, cells can switch to endocycles in response to conditional signals, which can have beneficial or pathological effects on tissues. However, the impact of these unscheduled endocycles on development is underexplored. Here, we use Drosophila ovarian somatic follicle cells as a model to examine the impact of unscheduled endocycles on tissue growth and function. Follicle cells normally switch to endocycles at mid-oogenesis. Inducing follicle cells to prematurely switch to endocycles resulted in lethality of the resulting embryos. Analysis of ovaries with premature follicle cell endocycles revealed aberrant follicular epithelial structure and pleiotropic defects in oocyte growth, developmental gene amplification, and the migration of a special set of follicle cells known as border cells. Overall, these findings reveal how unscheduled endocycles can disrupt tissue growth and function to cause aberrant development.

Single-cell morphological and transcriptome analysis unveil inhibitors of polyploid giant breast cancer cells in vitro

Considerable evidence suggests that breast cancer therapeutic resistance and relapse can be driven by polyploid giant cancer cells (PGCCs). The number of PGCCs increases with the stages of disease and therapeutic stress. Given the importance of PGCCs, it remains challenging to eradicate them. To discover effective anti-PGCC compounds, there is an unmet need to rapidly distinguish compounds that kill non-PGCCs, PGCCs, or both. Here, we establish a single-cell morphological analysis pipeline with a high throughput and great precision to characterize dynamics of individual cells. In this manner, we screen a library to identify promising compounds that inhibit all cancer cells or only PGCCs (e.g., regulators of HDAC, proteasome, and ferroptosis). Additionally, we perform scRNA-Seq to reveal altered cell cycle, metabolism, and ferroptosis sensitivity in breast PGCCs. The combination of single-cell morphological and molecular investigation reveals promising anti-PGCC strategies for breast cancer treatment and other malignancies.

Molecular mechanism of vimentin nuclear localization associated with the migration and invasion of daughter cells derived from polyploid giant cancer cells

BACKGROUND

Polyploid giant cancer cells (PGCCs), a specific type of cancer stem cells (CSCs), can be induced by hypoxic microenvironments, chemical reagents, radiotherapy, and Chinese herbal medicine. Moreover, PGCCs can produce daughter cells that undergo epithelial-mesenchymal transition, which leads to cancer recurrence and disseminated metastasis. Vimentin, a mesenchymal cell marker, is highly expressed in PGCCs and their daughter cells (PDCs) and drives migratory persistence. This study explored the molecular mechanisms by which vimentin synergistically regulates PGCCs to generate daughter cells with enhanced invasive and metastatic properties.

METHODS

Arsenic trioxide (ATO) was used to induce the formation of PGCCs in Hct116 and LoVo cells. Immunocytochemical and immunohistochemical assays were performed to determine the subcellular localization of vimentin. Cell function assays were performed to compare the invasive metastatic abilities of the PDCs and control cells. The molecular mechanisms underlying vimentin expression and nuclear translocation were investigated by real-time polymerase chain reaction, western blotting, cell function assays, cell transfection, co-immunoprecipitation, and chromatin immunoprecipitation, followed by sequencing. Finally, animal xenograft experiments and clinical colorectal cancer samples were used to study vimentin expression in tumor tissues.

RESULTS

Daughter cells derived from PGCCs showed strong proliferative, migratory, and invasive abilities, in which vimentin was highly expressed and located in both the cytoplasm and nucleus. Vimentin undergoes small ubiquitin-like modification (SUMOylation) by interacting with SUMO1 and SUMO2/3, which are associated with nuclear translocation. P62 regulates nuclear translocation of vimentin by controlling SUMO1 and SUMO2/3 expression. In the nucleus, vimentin acts as a transcription factor that regulates CDC42, cathepsin B, and cathepsin D to promote PDC invasion and migration. Furthermore, animal experiments and human colorectal cancer specimens have confirmed the nuclear translocation of vimentin.

CONCLUSION

P62-dependent SUMOylation of vimentin plays an important role in PDC migration and invasion. Vimentin nuclear translocation and overexpressed P62 of cancer cells may be used to predict patient prognosis, and targeting vimentin nuclear translocation may be a promising therapeutic strategy for metastatic cancers.

Computational Biology Helps Understand How Polyploid Giant Cancer Cells Drive Tumor Success

Precision and organization govern the cell cycle, ensuring normal proliferation. However, some cells may undergo abnormal cell divisions (neosis) or variations of mitotic cycles (endopolyploidy). Consequently, the formation of polyploid giant cancer cells (PGCCs), critical for tumor survival, resistance, and immortalization, can occur. Newly formed cells end up accessing numerous multicellular and unicellular programs that enable metastasis, drug resistance, tumor recurrence, and self-renewal or diverse clone formation. An integrative literature review was carried out, searching articles in several sites, including: PUBMED, NCBI-PMC, and Google Academic, published in English, indexed in referenced databases and without a publication time filter, but prioritizing articles from the last 3 years, to answer the following questions: (i) "What is the current knowledge about polyploidy in tumors?"; (ii) "What are the applications of computational studies for the understanding of cancer polyploidy?"; and (iii) "How do PGCCs contribute to tumorigenesis?"

Molecules promoting circulating clusters of cancer cells suggest novel therapeutic targets for treatment of metastatic cancers

Treatment of metastatic disease remains among the most challenging tasks in oncology. One of the early events that predicts a poor prognosis and precedes the development of metastasis is the occurrence of clusters of cancer cells in the blood flow. Moreover, the presence of heterogeneous clusters of cancerous and noncancerous cells in the circulation is even more dangerous. Review of pathological mechanisms and biological molecules directly involved in the formation and pathogenesis of the heterotypic circulating tumor cell (CTC) clusters revealed their common properties, which include increased adhesiveness, combined epithelial-mesenchymal phenotype, CTC-white blood cell interaction, and polyploidy. Several molecules involved in the heterotypic CTC interactions and their metastatic properties, including IL6R, CXCR4 and EPCAM, are targets of approved or experimental anticancer drugs. Accordingly, analysis of patient survival data from the published literature and public datasets revealed that the expression of several molecules affecting the formation of CTC clusters predicts patient survival in multiple cancer types. Thus, targeting of molecules involved in CTC heterotypic interactions might be a valuable strategy for the treatment of metastatic cancers.

Polyploid/Multinucleated Giant and Slow-Cycling Cancer Cell Enrichment in Response to X-ray Irradiation of Human Glioblastoma Multiforme Cells Differing in Radioresistance and TP53/PTEN Status

Radioresistance compromises the efficacy of radiotherapy for glioblastoma multiforme (GBM), the most devastating and common brain tumor. The present study investigated the relationship between radiation tolerance and formation of polyploid/multinucleated giant (PGCC/MGCC) and quiescent/senescent slow-cycling cancer cells in human U-87, LN-229, and U-251 cell lines differing in TP53/PTEN status and radioresistance. We found significant enrichment in MGCC populations of U-87 and LN-229 cell lines, and generation of numerous small mononuclear (called Raju cells, or RJ cells) U-87-derived cells that eventually form cell colonies, in a process termed neosis, in response to X-ray irradiation (IR) at single acute therapeutic doses of 2-6 Gy. For the first time, single-cell high-content imaging and analysis of Ki-67- and EdU-coupled fluorescence demonstrated that the IR exposure dose-dependently augments two distinct GBM cell populations. Bifurcation of Ki-67 staining suggests fast-cycling and slow-cycling populations with a normal-sized nuclear area, and with an enlarged nuclear area, including one resembling the size of PGCC/MGCCs, that likely underlie the highest radioresistance and propensity for repopulation of U-87 cells. Proliferative activity and anchorage-independent survival of GBM cell lines seem to be related to neosis, low level of apoptosis, fraction of prematurely stress-induced senescent MGCCs, and the expression of p63 and p73, members of p53 family transcription factors, but not to the mutant p53. Collectively, our data support the importance of the TP53wt/PTENmut genotype for the maintenance of cycling radioresistant U-87 cells to produce a significant amount of senescent MGCCs as an IR stress-induced adaptation response to therapeutic irradiation doses.

CCR3 blockage elicits polyploidization associated with the signatures of epithelial-mesenchymal transition in carcinoma cell lines

Malignant features such as the acquisition of metastatic ability, stemness of cells, and therapeutic resistance of cancer cells are associated with epithelial-mesenchymal transition (EMT) accompanied by changes in motility and morphology. Recent reports implicated that the formation of polyploid giant cancer cells (PGCCs) in human malignancy correlated with the EMT processes. Chemokines are often involved in the regulation of cancer cell migration into tissues, and various types of human cancers exhibit enhanced expression of chemokine receptors, which could augment intrinsic potentials such as invasive activity, proliferating ability, and survival capacity in cancer cells. Nevertheless, the contribution of CCR3 in malignant cancer cells is controversial because it is a well-known primal receptor for the migration of eosinophils, one of the cells of the innate immune system. Here, we explored the blockage of chemokine receptor CCR3 in carcinoma cell lines and found that inhibition of CCR3 induced the formation of polyploid giant cells and stabilization of β-catenin via the PI3K/Akt/GSK-3β signaling pathway, which are processes associated with EMT. As a result of CCR3 inhibition, converted cells acquired enhanced mobile and proliferation abilities. In summary, these data indicate that modulation of the CCR3/PI3K/Akt/GSK-3β signaling pathway regulates polyploidization associated with the EMT processes.

Polyploid giant cancer cells and cancer progression

Polyploid giant cancer cells (PGCCs) are an important feature of cellular atypia, the detailed mechanisms of their formation and function remain unclear. PGCCs were previously thought to be derived from repeated mitosis/cytokinesis failure, with no intrinsic ability to proliferate and divide. However, recently, PGCCs have been confirmed to have cancer stem cell (CSC)-like characteristics, and generate progeny cells through asymmetric division, which express epithelial-mesenchymal transition-related markers to promote invasion and migration. The formation of PGCCs can be attributed to multiple stimulating factors, including hypoxia, chemotherapeutic reagents, and radiation, can induce the formation of PGCCs, by regulating the cell cycle and cell fusion-related protein expression. The properties of CSCs suggest that PGCCs can be induced to differentiate into non-tumor cells, and produce erythrocytes composed of embryonic hemoglobin, which have a high affinity for oxygen, and thereby allow PGCCs survival from the severe hypoxia. The number of PGCCs is associated with metastasis, chemoradiotherapy resistance, and recurrence of malignant tumors. Targeting relevant proteins or signaling pathways related with the formation and transdifferentiation of adipose tissue and cartilage in PGCCs may provide new strategies for solid tumor therapy.

Isoliquiritigenin inhibits non-small cell lung cancer progression via m6A/IGF2BP3-dependent TWIST1 mRNA stabilization

BACKGROUND

N⁶-methyladenosine (m⁶A) has been identified to regulate the tumorigenesis and development of various tumors, including non-small cell lung cancer (NSCLC). Isoliquiritigenin (ISL), derived from the Chinese herb licorice, shows a significant anti-tumor activity on multiple human cancers. However, the role of ISL on NSCLC through m⁶A is still unclear.

PURPOSE

Here, we investigated the anti-tumor effect of ISL on NSCLC, and explored whether ISL affected the NSCLC phenotype by modulating its m⁶A modification.

METHODS

Cell proliferation, migration and invasion assays were performed to evaluate the inhibitory effects of ISL on NSCLC cells. M⁶A enrichment was determined by m⁶A quantitative analysis. The mechanism regarding IGF2BP3 was explored using RIP-PCR, MeRIP-qPCR and RNA decay analysis.

RESULTS

ISL significantly repressed the proliferation, migration and invasion of NSCLC cells in vitro. In addition, m⁶A reader IGF2BP3 expression significantly increased in NSCLC tissues compared to adjacent tissues, and was positively correlated with NSCLC patients' poor survival. Mechanistically, ISL reduced m⁶A modification and down-regulated IGF2BP3 expression in NSCLC. Furthermore, IGF2BP3 enhanced the mRNA stability of twist family bHLH transcription factor 1 (TWIST1) in m⁶A-dependent manner. Moreover, ISL treatment combined with TWSIT1 knockdown effectively reversed IGF2BP3 overexpression-induced NSCLC cells' proliferation, migration and invasion.

CONCLUSION

Our findings uncover that ISL might function as an anticarcinogen through targeting IGF2BP3/m⁶A/TWIST1 axis for NSCLC.

Targeting tumor cell senescence and polyploidy as potential therapeutic strategies

Senescence is a unique state of growth arrest that develops in response to a plethora of cellular stresses, including replicative exhaustion, oxidative injury, and genotoxic insults. Senescence has been implicated in the pathogenesis of multiple aging-related pathologies, including cancer. In cancer, senescence plays a dual role, initially acting as a barrier against tumor progression by enforcing a durable growth arrest in premalignant cells, but potentially promoting malignant transformation in neighboring cells through the secretion of pro-tumorigenic drivers. Moreover, senescence is induced in tumor cells upon exposure to a wide variety of conventional and targeted anticancer drugs (termed Therapy-Induced Senescence-TIS), representing a critical contributing factor to therapeutic outcomes. As with replicative or oxidative senescence, TIS manifests as a complex phenotype of macromolecular damage, energetic dysregulation, and altered gene expression. Senescent cells are also frequently polyploid. In vitro studies have suggested that polyploidy may confer upon senescent tumor cells the ability to escape from growth arrest, thereby providing an additional avenue whereby tumor cells escape the lethality of anticancer treatment. Polyploidy in tumor cells is also associated with persistent energy production, chromatin remodeling, self-renewal, stemness and drug resistance - features that are also associated with escape from senescence and conversion to a more malignant phenotype. However, senescent cells are highly heterogenous and can present with variable phenotypes, where polyploidy is one component of a complex reversion process. Lastly, emerging efforts to pharmacologically target polyploid tumor cells might pave the way towards the identification of novel targets for the elimination of senescent tumor cells by the incorporation of senolytic agents into cancer therapeutic strategies.

Long non-coding RNA CATIP antisense RNA 1 (lncRNA CATIP-AS1) downregulation contributes to the progression and metastasis of thyroid cancer via epithelial-mesenchymal transition (EMT) pathway

Thyroid cancer (THCA) is the most common cancer of the endocrine system across the globe. To date, the mechanism of development of THCA remains scarcely known. In this study, we aim to elucidate the long non-coding RNA CATIP antisense RNA 1 (lncRNA CATIP-AS1/CATIP-AS1) role in the pathogenesis of THCA and its regulatory mechanism. The result shows that the CATIP-AS1 was significantly downregulated in THCA tissues and cells and was associated with a poor prognosis of patients diagnosed with THCA. The overexpression of CATIP-AS1 significantly inhibited THCA cell proliferation, migration, and epithelial–mesenchymal transition (EMT) but increased the THCA cell apoptosis. We found that CATIP-AS1 endogenously sponges miR-515-5p and its overexpression could inhibit miR-515-5p regulatory effect. Moreover, the overexpression of miR-515-5p repressed the Smad4 expression level, consequently reversed the inhibiting effect of overexpressed CATIP-AS1 on the proliferation, and migration of THCA cell. It also reversed the increased THCA cell apoptosis and the downregulated-CATIP-AS1-induced cell EMT inhibition. Summarily, we demonstrated that the CATIP-AS1 promotes the progression and metastasis of THCA via EMT pathway partly through regulating the miR-515-5p and Smad4 expression in THCA cell. The CATIP-AS1 could be a promising biomarker for early THCA detection and prognosis and a possible therapeutic target for its treatment.

Arsenic Trioxide Promotes Tumor Progression by Inducing the Formation of PGCCs and Embryonic Hemoglobin in Colon Cancer Cells

Arsenic trioxide (ATO) has been used to treat acute promyelocytic leukemia. However, it is not effective in treating solid tumors such as colorectal cancer. We have previously reported that polyploid giant cancer cells (PGCCs) exhibiting the characteristics of cancer stem cells can be generated by various inducers. In this study, ATO was used to induce the formation of PGCCs in LoVo and Hct116 colon cancer cell lines. The migration, invasion, and proliferation abilities of colon cancer cells with and without ATO treatment were assessed by wound-healing, transwell, and plate colony formation assays. The expression of epithelial to mesenchymal transition-related proteins and erythroid differentiation-related proteins in colon cancer cells was further evaluated by western blot and immunocytochemical assays. LoVo and Hct116 cells were transfected with a eukaryotic expression vector for green fluorescent protein (GFP), red fluorescent protein (RFP), H2B-GFP, and H2B-mCherry to study PGCCs formation via cell fusion. WB and ICC assays were performed to assess the expression of cell fusion-related proteins. MG132, small interfering RNA-glial cell missing 1 (GCM1), and chromatin immunoprecipitation-polymerase chain reaction assays were performed to study the role of GCM1/syncytin-1-mediated cell fusion. Clinically, the significance of cell fusion-related proteins and erythroid differentiation-related proteins expression in human colorectal cancer tissues was evaluated. Results of our study showed that ATO induced the formation of PGCCs, and the daughter cells derived from PGCCs gained a mesenchymal phenotype and exhibited strong migration, invasion, and proliferation abilities. PGCCs also produced embryonic hemoglobin-delta and -zeta with strong oxygen-binding ability and erythroid differentiation-related proteins after ATO treatment. In addition, cell fusion was observed during the formation of PGCCs, indicated by the presence of yellow fluorescence via the GCM1/syncytin-1 signaling pathway. Clinically, the expression of cell fusion-related and erythroid differentiation-related proteins gradually increased with the progression of human colorectal cancer tissues. In conclusion, ATO can promote tumor progression by inducing the formation of PGCCs via GCM1/syncytin-1-mediated cell fusion. PGCCs can produce daughter cells with high invasion and migration abilities and embryonic hemoglobin with strong oxygen binding ability, promoting survival of tumor cells in a hypoxic microenvironment.

Characteristics and clinical significance of polyploid giant cancer cells in laryngeal carcinoma

OBJECTIVES

We aimed to construct an induction system for polyploid giant cancer cells (PGCCs), as well as to investigate PGCC features and clinical significance.

METHODS

A laryngeal neoplasm-PGCC induction system was constructed using paclitaxel liposomes (PTX). We used western blots to compare expression of epithelial-mesenchymal transition-related proteins, stem cell interrelated proteins, and cyclin-associated proteins. We then measured PGCC count in tissue samples of patients with laryngeal neoplasms and analyzed its relationship with prognosis. Statistical significance was determined using t-tests.

RESULTS

PTX successfully induced PGCCs. Western blotting showed that CyclinB1, CDC25C, CDK1, E-cadherin, and EIF-4A expression decreased in PGCCs compared with normal cancer cells, whereas vimentin and CD133 expression increased. Number of PGCCs in laryngeal cancer tissues and overall survival time were inversely correlated (P < .05).

CONCLUSIONS

PTX successfully induces PGCC formation in laryngeal carcinoma, which may be the cause of poor prognosis in patients with laryngeal cancer.Level of Evidence: 4.

Stress-Induced Polyploid Giant Cancer Cells: Unique Way of Formation and Non-Negligible Characteristics

Polyploidy is a conserved mechanism in cell development and stress responses. Multiple stresses of treatment, including radiation and chemotherapy drugs, can induce the polyploidization of tumor cells. Through endoreplication or cell fusion, diploid tumor cells convert into giant tumor cells with single large nuclei or multiple small nucleuses. Some of the stress-induced colossal cells, which were previously thought to be senescent and have no ability to proliferate, can escape the fate of death by a special way. They can remain alive at least before producing progeny cells through asymmetric cell division, a depolyploidization way named neosis. Those large and danger cells are recognized as polyploid giant cancer cells (PGCCs). Such cells are under suspicion of being highly related to tumor recurrence and metastasis after treatment and can bring new targets for cancer therapy. However, differences in formation mechanisms between PGCCs and well-accepted polyploid cancer cells are largely unknown. In this review, the methods used in different studies to induce polyploid cells are summarized, and several mechanisms of polyploidization are demonstrated. Besides, we discuss some characteristics related to the poor prognosis caused by PGCCs in order to provide readers with a more comprehensive understanding of these huge cells.

High Migration and Invasion Ability of PGCCs and Their Daughter Cells Associated With the Nuclear Localization of S100A10 Modified by SUMOylation

Our previous studies have confirmed that cobalt chloride (CoCl2) or chemoradiotherapy could induce the formation of polyploid tumor giant cells (PGCCs). Polyploid giant cancer cells are a special subpopulation of cancer cells that contribute to solid tumor heterogeneity. The size of PGCC was at least three times larger than regular diploid cancer cells. PGCCs have the properties of cancer stem cells (CSCs) and can express CSC markers CD44 and CD133. Daughter cells derived from PGCCs have strong proliferation, infiltration and migration abilities. However, the detailed molecular mechanism of daughter cells expressing mesenchymal phenotype and displaying strong abilities of proliferation and migration is unclear. As a plasminogen receptor, S100A10 which is closely associated with the invasion and metastasis of malignant tumors, was highly expressed in PGCCs with their daughter cells. In this study, CoCl2 was used to induce the formation of PGCCs in LoVo and HCT116 CRC cells. Cell functional experiments, co-immunoprecipitation, MG132 and ginkgolic acid treatment, western blot, and ChIP-Seq were used to identify the mechanism of S100A10 nuclear location. The proliferation and migration abilities of PGCCs and their daughter cells decreased significantly after S100A10 knockdown. In the control cells, S100A10 was mainly ubiquitinated, while in PGCCs and daughter cells, S100A10 was mainly SUMOylated, which was associated with S100A10 nuclear location. After SUMO1 was inhibited, the nuclear S100A10 in PGCCs and daughter cells decreased, and their proliferation and migration abilities significantly decreased. ChIP-Seq combined with real-time fluorescent quantitative PCR showed that S100A10 regulated the expression of neutrophil defensin 3 (DEFA3), receptor-type tyrosine-protein phosphatase N2 (PTPRN2), and rho guanine nucleotide exchange factor 18 (ARHGEF18), which were associated with actin dynamics and cytoskeleton remodeling. The expression of S100A10 in the nuclei and cytoplasm of rectal cancer after neoadjuvant chemoradiation (nCRT) and liver metastases increased compared with that in rectal cancer without nCRT. Taken together, the expression and nuclear localization of S100A10 modified by SUMOylation were associated with the high proliferation and migration of PGCCs and their daughter cells, and the differentiation, metastases, and relapse of CRCs by regulating the expression of ARHGEF18, PTPRN2, and DEFA3.

Human CD133-positive hematopoietic progenitor cells enhance the malignancy of breast cancer cells

BACKGROUND

Human CD133+ hematopoietic progenitor cells (HPCs) are a specific subset of cells that can regulate tumor malignancy. However, the mechanism by which CD133+ HPCs affect the malignancy of human breast cancer has not been reported.

METHODS

CD133+ HPCs were isolated and purified from human umbilical cord blood (UCB). We used in vitro culture of MCF-7 and MDA-MB-231 cell lines, and MCF-7 and MDA-MB-231 cells in nude mice to evaluate whether CD133+ HPCs affected the apoptosis, proliferation, invasion and epithelial mesenchymal transition EMT of breast cancer cells.

RESULTS

Co-culture with CD133+ HPCs, but not UCB CD133- cells, promoted the proliferation of human breast cancer MCF-7 and MDA-MB-231 cells, accompanied by reducing in vitro spontaneous apoptosis. Co-administration of these two lines with CD133+ HPCs significantly enhanced the growth of implanted breast cancer in vivo. Furthermore, co-culture with CD133+ HPCs, enhanced the invasion of breast cancer cells, N-cadherin and Vimentin expression, but reduced E-cadherin expression in breast cancer cells.

CONCLUSIONS

Our study demonstrated that CD133+ HPCs enhance the malignancy of breast cancer cells by attenuating spontaneous apoptosis and promoting the process of epithelial mesenchymal transition. These findings may provide new insights into the role of human CD133+ HPCs in breast cancer pathogenesis. Therefore, CD133+ HPCs may be a new therapeutic target for inhibiting the progression of breast cancer.

Loss of Aurora Kinase Signaling Allows Lung Cancer Cells to Adopt Endoreplication and Form Polyploid Giant Cancer Cells That Resist Antimitotic Drugs

Polyploid giant cancer cells (PGCC) are common in tumors and have been associated with resistance to cancer therapy, tumor relapse, malignancy, immunosuppression, metastasis, cancer stem cell production, and modulation of the tumor microenvironment. However, the molecular mechanisms that cause these cells to form are not yet known. In this study, we discover that Aurora kinases are synergistic determinants of a switch from the proliferative cell cycle to polyploid growth and multinucleation in lung cancer cell lines. When Aurora kinases were inhibited together, lung cancer cells uniformly grew into multinucleated PGCCs. These cells adopted an endoreplication in which the genome replicates, mitosis is omitted, and cells grow in size. Consequently, such cells continued to safely grow in the presence of antimitotic agents. These PGCC re-entered the proliferative cell cycle and grew in cell number when treatment was terminated. Thus, PGCC formation might represent a fundamental cellular response to Aurora kinase inhibitors and contributes to therapy resistance or tumor relapse. SIGNIFICANCE: These findings provide a novel insight about how cancer cells respond to Aurora kinase inhibitors and identify a new mechanism responsible for resistance to these agents and other antimitotic drugs.

FGFR2/STAT3 Signaling Pathway Involves in the Development of MMTV-Related Spontaneous Breast Cancer in TA2 Mice

The Tientsin Albino 2 (TA2) mouse has a high incidence of spontaneous breast cancer (SBC) in the absence of external inducers or carcinogens. The initiation of SBC is related to mouse mammary tumor virus (MMTV) infection and pregnancy. Pathologic analysis showed that breast cancer cells in TA2 mice are triple negative. Our previous study confirmed that fibroblast growth factor receptor 2 (FGFR2) expression increased in SBC tissue compared to that in their corresponding normal breast tissues of TA2 mice. The present study focused on the function of the FGFR2/STAT3 signaling pathway in the initiation of SBC. In this study, the expression of FGF3, FGFR2, STAT3, p-STAT3Tyr705, and p-STAT3Ser727 was detected in serum and normal mammary gland tissues of TA2 mice with different number of pregnancies and SBC. The proliferation, invasiveness, and migration abilities of MA-891 cells from TA2 SBC were compared before and after cryptotanshinone and Stattic treatment. Transient siRNA transfection was used to detect the invasiveness, and migration abilities to avoid the off-targets effects. Downstream protein expression of STAT3 was also detected in MA-891 cells and TA2 xenografts from MA-891 inoculation. In addition, STAT3 expression was analyzed in 139 cases of human breast cancer including 117 cases of non-triple negative breast cancer (non-TNBC) (group I) and 22 cases of triple-negative breast cancer (TNBC) (group II). Results of our study confirmed that MMTV-LTR amplification, and FGFR2, p-STAT3Tyr705, p-STAT3Ser727 expression increased with the number of pregnancies in the breast tissue of TA2 mice and were the highest in SBC. Serum FGF3 expression of SBC was higher than it of TA2 mice with different number of pregnancies. After STAT3 was inhibited, the abilities of proliferation, invasiveness, and migration in MA-891 decreased and the expression levels of STAT3, p-STAT3Ser727, p-STAT3Tyr705, Bcl2, cyclin D1, and c-myc in MA-891 and animal xenografts were also down-regulated. In human breast cancer, STAT3 expression was significantly higher in TNBC than that in non-TNBC. Our results showed that the FGFR2/STAT3 signaling pathway may be related to SBC initiation in TA2 mice. Inhibition of STAT3 can decrease proliferation, invasiveness, and migration in MA-891 cells and the growth of TA2 xenografts.

Giants and monsters: Unexpected characters in the story of cancer recurrence

Polyploid giant cancer cells (PGCC) constitute a dangerous subpopulation of cancer cells and are a driving force in cancer recurrence. These unique cells arise from diploid tumor cells in response to stress encountered in the tumor microenvironment or during cancer therapy. PGCC are greatly dedifferentiated, acquire pluripotency, and are able to replicate through a form of asymmetric division called neosis, which results in new populations that are themselves able to differentiate into new cell types or to re-establish tumors. Progeny tend to be more genetically unstable than the founding population due to the dysregulation required to transition through a PGCC state. Therefore, cancers that escape stressors through this mechanism tend to re-emerge with a more aggressive phenotype that is therapy resistant. This review focuses on the clinical significance of PGCC, the need for standardized nomenclature and molecular markers, as well as possible avenues to develop therapies aimed at PGCC and the process of neosis. The biology underlying the development of PGCC including cell cycle checkpoint dysregulation, stress responses, dedifferentiation, stemness and epithelial-mesenchymal transition is discussed.