Identification and characterization of ovarian cancer-initiating cells from primary human tumors

1α,25-hydroxyvitamin D/VDR suppresses stem-like properties of ovarian cancer cells by restraining nuclear translocation of β-catenin

Several studies have indicated that 1α,25-hydroxyvitamin D [1α,25(OH)2D3] inhibits the proliferation and metastasis of cancer cells through suppressing epithelial-mesenchymal transition. However, its influence on the translocation of β-catenin remains unclear. In the present study, ovarian cancer stem-like cells (CSCs), including side population (SP) and CD44+/CD117+, were isolated from mouse ovarian surface epithelial (MOSE) cells with malignant transformation. The findings revealed that 1α,25(OH)2D3 obviously reduced the sphere-forming ability, as well as Notch1 and Klf levels. Moreover, the limiting dilution assay demonstrated that 1α,25(OH)2D3 effectively hindered the tumorigenesis of ovarian CSCs in vitro. Notably, treatment with 1α,25(OH)2D3 led to a substantial increase in the cell population of CD44+/CD117+ forming one tumor from ≤ 100 to 445 in orthotopic transplanted model, indicating a pronounced suppression of stemness of ovarian CSCs. Additionally, 1α,25(OH)2D3 robustly promoted the translocation of β-catenin from the nuclear to the cytoplasm through directly binding to VDR, which resulted in decreased levels of c-Myc and CyclinD1 within late MOSE cells. Taken together, these results strongly supported the role of 1α,25(OH)2D3 in inhibiting stem-like properties in ovarian cancer cells by restraining nuclear translocation of β-catenin, thereby offering a promising target for cancer therapeutics.

Research progress on m6A demethylase FTO and its role in gynecological tumors

Recent advances in genomic research have increasingly focused on the fat mass- and obesity-associated (FTO) gene due to its notable correlation with obesity. Initially explored for its contribution to increased body weight, FTO was later discovered to function as an m6A demethylase. This pivotal role enhances our understanding of its broader implications across various pathologies. Epigenetic modifications, such as m6A, have been implicated in gynecological cancers, including ovarian, endometrial, and cervical malignancies. However, the precise mechanisms by which FTO influences the development of gynecological cancers remain largely unknown. This analysis underscores the growing relevance of investigations into the FTO gene in elucidating the mechanisms underlying gynecological cancers and exploring potential therapeutic avenues.

STAU1-mediated CNBP mRNA degradation by LINC00665 alters stem cell characteristics in ovarian cancer

BACKGROUND

To investigate the role of lncRNA LINC00665 in modulating ovarian cancer stemness and its influence on treatment resistance and cancer development.

METHODS

We isolated ovarian cancer stem cells (OCSCs) from the COC1 cell line using a combination of chemotherapeutic agents and growth factors, and verified their stemness through western blotting and immunofluorescence for stem cell markers. Employing bioinformatics, we identified lncRNAs associated with ovarian cancer, with a focus on LINC00665 and its interaction with the CNBP mRNA. In situ hybridization, immunohistochemistry, and qPCR were utilized to examine their expression and localization, alongside functional assays to determine the effects of LINC00665 on CNBP.

RESULTS

LINC00665 employs its Alu elements to interact with the 3'-UTR of CNBP mRNA, targeting it for degradation. This molecular crosstalk enhances stemness by promoting the STAU1-mediated decay of CNBP mRNA, thereby modulating the Wnt and Notch signaling cascades that are pivotal for maintaining CSC characteristics and driving tumor progression. These mechanistic insights were corroborated by a series of in vitro assays and validated in vivo using tumor xenograft models. Furthermore, we established a positive correlation between elevated CNBP levels and increased disease-free survival in patients with ovarian cancer, underscoring the prognostic value of CNBP in this context.

CONCLUSIONS

lncRNA LINC00665 enhances stemness in ovarian cancer by mediating the degradation of CNBP mRNA, thereby identifying LINC00665 as a potential therapeutic target to counteract drug resistance and tumor recurrence associated with CSCs.

A stemness-based signature with inspiring indications in discriminating the prognosis, immune response, and somatic mutation of endometrial cancer patients revealed by machine learning

Endometrial cancer (EC) is a fatal gynecologic tumor. Bioinformatic tools are increasingly developed to screen out molecular targets related to EC. Our study aimed to identify stemness-related prognostic biomarkers for new therapeutic strategies in EC. In this study, we explored the prognostic value of cancer stem cells (CSCs), characterized by self-renewal and unlimited proliferation, and its correlation with immune infiltrates in EC. Transcriptome and somatic mutation profiles of EC were downloaded from TCGA database. Based on their stemness signature and DEGs, EC patients were divided into two subtypes via consensus clustering, and patients in Stemness Subtype I presented significantly better OS and DFS than Stemness Subtype II. Subtype I also displayed better clinicopathological features, and genomic variations demonstrated different somatic mutation from subtype II. Additionally, two stemness subtypes had distinct tumor immune microenvironment patterns. In the end, three machine learning algorithms were applied to construct a 7-gene stemness subtype risk model, which were further validated in an external independent EC cohort in our hospital. This novel stemness-based classification could provide a promising prognostic predictor for EC and may guide physicians in selecting potential responders for preferential use of immunotherapy. This novel stemness-dependent classification method has high value in predicting the prognosis, and also provides a reference for clinicians in selecting sensitive immunotherapy methods for EC patients.

Extracellular vesicles and cancer stem cells: a deadly duo in tumor progression

The global incidence of cancer is increasing, with estimates suggesting that there will be 26 million new cases and 17 million deaths per year by 2030. Cancer stem cells (CSCs) and extracellular vesicles (EVs) are key to the resistance and advancement of cancer. They play a crucial role in tumor dynamics and resistance to therapy. CSCs, initially discovered in acute myeloid leukemia, are well-known for their involvement in tumor initiation, progression, and relapse, mostly because of their distinct characteristics, such as resistance to drugs and the ability to self-renew. EVs, which include exosomes, microvesicles, and apoptotic bodies, play a vital role in facilitating communication between cells within the tumor microenvironment (TME). They have a significant impact on cellular behaviors and contribute to genetic and epigenetic changes. This paper analyzes the mutually beneficial association between CSCs and EVs, emphasizing their role in promoting tumor spread and developing resistance mechanisms. This review aims to investigate the interaction between these entities in order to discover new approaches for attacking the complex machinery of cancer cells. It highlights the significance of CSCs and EVs as crucial targets in the advancement of novel cancer treatments, which helps stimulate additional research, promote progress in ideas for cancer treatment, and provide renewed optimism in the effort to reduce the burden of cancer.

Unveiling stem-like traits and chemoresistance mechanisms in ovarian cancer cells through the TGFβ1-PITX2A/B signaling axis

Ovarian cancer (OC) is the deadliest gynecological malignancy, having a high mortality rate due to its asymptomatic nature, chemoresistance, and recurrence. However, the proper mechanistic knowledge behind these phenomena is still inadequate. Cancer recurrence is commonly observed due to cancer stem cells which also show chemoresistance. We aimed to decipher the molecular mechanism behind chemoresistance and stemness in OC. Earlier studies suggested that PITX2, a homeobox transcription factor and, its different isoforms are associated with OC progression upon regulating different signaling pathways. Moreover, they regulate the expression of drug efflux transporters in kidney and colon cancer, rendering chemoresistance properties in the tumor cell. Considering these backgrounds, we decided to look for the role of PITX2 isoforms in promoting stemness and chemoresistance in OC cells. In this study, PITX2A/B has been shown to promote stemness and to enhance the transcription of ABCB1. PITX2 has been discovered to augment ABCB1 gene expression by directly binding to its promoter. To further investigate the regulatory mechanism of PITX2 gene expression, we found that TGFβ signaling could augment the PITX2A/B expression through both SMAD and non-SMAD signaling pathways. Collectively, we conclude that TGFβ1-activated PITX2A/B induces stem-like features and chemoresistance properties in the OC cells.

Advances in ovarian tumor stem cells and therapy

Ovarian cancer is considered the most lethal among all gynecological malignancies due to its early metastatic dissemination, extensive spread, and malignant ascites. The current standard of care for advanced ovarian cancer involves a combination of cytoreductive surgery and chemotherapy utilizing platinum-based and taxane-based agents. Although initial treatment yields clinical remission in 70-80% of patients, the majority eventually develop treatment resistance and tumor recurrence. A growing body of evidence indicates the existence of cancer stem cells within diverse solid tumors, including ovarian cancer, which function as a subpopulation to propel tumor growth and disease advancement by means of drug resistance, recurrence, and metastasis. The presence of ovarian cancer stem cells is widely considered to be a significant contributor to the unfavorable clinical outcomes observed in patients with ovarian cancer, as they play a crucial role in mediating chemotherapy resistance, recurrence, and metastasis. Ovarian cancer stem cells possess the capacity to reassemble within the entirety of the tumor following conventional treatment, thereby instigating the recurrence of ovarian cancer and inducing resistance to treatment. Consequently, the creation of therapeutic approaches aimed at eliminating ovarian cancer stem cells holds great potential for the management of ovarian cancer. These cells are regarded as one of the most auspicious targets and mechanisms for the treatment of ovarian cancer. There is a pressing need for a comprehensive comprehension of the fundamental mechanisms of ovarian cancer's recurrence, metastasis, and drug resistance, alongside the development of effective strategies to overcome chemoresistance, metastasis, and recurrence. The implementation of cancer stem cell therapies may potentially augment the tumor cells' sensitivity to existing chemotherapy protocols, thereby mitigating the risks of tumor metastasis and recurrence, and ultimately improving the survival rates of ovarian cancer patients.

Shear-wave elastography in renal stiffness in children with hematuria and/or proteinuria

BACKGROUND

We sought to evaluate renal stiffness in children with hematuria and/or proteinuria using shear wave elastography (SWE) and to investigate the clinical value of renal stiffness in children with hematuria and/or proteinuria.

METHODS

According to the results of urinary occult blood and urinary protein tests, 349 pediatric patients were categorized into one of four groups: pure hematuria (HU), pure proteinuria (PU), concomitant hematuria and proteinuria (HUPU), or control (non-HUPU). Patient demographic data, laboratory test results, and renal ultrasound data were collected.

RESULTS

There were significant differences in cortical/medullary elasticity among the four groups (the most sensitive cutoff value between HU and PU was 1.72) (P < 0.05). We found that hematuria and proteinuria interacted with renal cortical elasticity (P < 0.05) but that hematuria and proteinuria did not interact with renal medullary elasticity or cortical/medullary elasticity (P > 0.05). Renal elasticity values correlated with sex, age, body surface area, body mass index, qualitative urinary protein, urine N-acetyl-β-D-glucosaminidase, 24-hour urinary protein quantity, renal volume, and renal cortical thickness (P < 0.05).

CONCLUSIONS

SWE can be used to detect changes in renal stiffness in children with hematuria and/or proteinuria. SWE is beneficial for the early detection of glomerular disease in children with abnormal urine test results.

IMPACT

This study evaluated the utility of shear wave elastography for the assessment of renal elasticity in pediatric patients presenting with hematuria and/or proteinuria. Children with pure proteinuria had significantly higher renal cortical/medullary elasticity values than those with pure hematuria. An interaction effect between hematuria and proteinuria on renal cortical stiffness was observed. Shear wave elastography can be used as a tool to assess early renal injury in children with urinalysis abnormalities.

Fluorescent imaging probes for in vivo ovarian cancer targeted detection and surgery

Ovarian cancer is the most lethal gynecological cancer, with a survival rate of approximately 40% at five years from the diagno. The first-line treatment consists of cytoreductive surgery combined with chemotherapy (platinum- and taxane-based drugs). To date, the main prognostic factor is related to the complete surgical resection of tumor lesions, including occult micrometastases. The presence of minimal residual diseases not detected by visual inspection and palpation during surgery significantly increases the risk of disease relapse. Intraoperative fluorescence imaging systems have the potential to improve surgical outcomes. Fluorescent tracers administered to the patient may support surgeons for better real-time visualization of tumor lesions during cytoreductive procedures. In the last decade, consistent with the discovery of an increasing number of ovarian cancer-specific targets, a wide range of fluorescent agents were identified to be employed for intraoperatively detecting ovarian cancer. Here, we present a collection of fluorescent probes designed and developed for fluorescence-guided ovarian cancer surgery. Original articles published between 2011 and November 2022 focusing on fluorescent probes, currently under preclinical and clinical investigation, were searched in PubMed. The keywords used were targeted detection, ovarian cancer, fluorescent probe, near-infrared fluorescence, fluorescence-guided surgery, and intraoperative imaging. All identified papers were English-language full-text papers, and probes were classified based on the location of the biological target: intracellular, membrane, and extracellular.

Exploring the Potential of Natural Killer Cell-Based Immunotherapy in Targeting High-Grade Serous Ovarian Carcinomas

High-grade serous ovarian cancers (HGSOCs) likely consist of poorly differentiated stem-like cells (PDSLCs) and differentiated tumor cells. Conventional therapeutics are incapable of completely eradicating PDSLCs, contributing to disease progression and tumor relapse. Primary NK cells are known to effectively lyse PDSLCs, but they exhibit low or minimal cytotoxic potential against well-differentiated tumors. We have introduced and discussed the characteristics of super-charged NK (sNK) cells in this review. sNK cells, in comparison to primary NK cells, exhibit a significantly higher capability for the direct killing of both PDSLCs and well-differentiated tumors. In addition, sNK cells secrete significantly higher levels of cytokines, especially those known to induce the differentiation of tumors. In addition, we propose that a combination of sNK and chemotherapy could be one of the most effective strategies to eliminate the heterogeneous population of ovarian tumors; sNK cells can lyse both PDSLCs and well-differentiated tumors, induce the differentiation of PDSLCs, and could be used in combination with chemotherapy to target both well-differentiated and NK-induced differentiated tumors.

Blocking Oncostatin M receptor abrogates STAT3 mediated integrin signaling and overcomes chemoresistance in ovarian cancer

Chemotherapy such as cisplatin is widely used to treat ovarian cancer either before or after surgical debulking. However, cancer relapse due to chemotherapy resistance is a major challenge in the treatment of ovarian cancer. The underlying mechanisms related to chemotherapy resistance remain largely unclear. Therefore, identification of effective therapeutic strategies is urgently needed to overcome therapy resistance. Transcriptome-based analysis, in vitro studies and functional assays identified that cisplatin-resistant ovarian cancer cells express high levels of OSMR compared to cisplatin sensitive cells. Furthermore, OSMR expression associated with a module of integrin family genes and predominantly linked with integrin αV (ITGAV) and integrin β3 (ITGB3) for cisplatin resistance. Using ectopic expression and knockdown approaches, we proved that OSMR directly regulates ITGAV and ITGB3 gene expression through STAT3 activation. Notably, targeting OSMR using anti-OSMR human antibody inhibited the growth and metastasis of ovarian cancer cells and sensitized cisplatin treatment. Taken together, our results underscore the pivotal role of OSMR as a requirement for cisplatin resistance in ovarian cancer. Notably, OSMR fostered the expression of a distinct set of integrin genes, which in turn resulted into a crosstalk between OSMR and integrins for signaling activation that is critical for cisplatin resistance. Therefore, targeting OSMR emerges as a promising and viable strategy to reverse cisplatin-resistance in ovarian cancer.

The microRNA Let-7 and its exosomal form: Epigenetic regulators of gynecological cancers

Many types of gynecological cancer (GC) are often silent until they reach an advanced stage, and are therefore often diagnosed too late for effective treatment. Hence, there is a real need for more efficient diagnosis and treatment for patients with GC. During recent years, researchers have increasingly studied the impact of microRNAs cancer development, leading to a number of applications in detection and treatment. MicroRNAs are a particular group of tiny RNA molecules that regulate regular gene expression by affecting the translation process. The downregulation of numerous miRNAs has been observed in human malignancies. Let-7 is an example of a miRNA that controls cellular processes as well as signaling cascades to affect post-transcriptional gene expression. Recent research supports the hypothesis that enhancing let-7 expression in those cancers where it is downregulated may be a potential treatment option. Exosomes are tiny vesicles that move through body fluids and can include components like miRNAs (including let-7) that are important for communication between cells. Studies proved that exosomes are able to enhance tumor growth, angiogenesis, chemoresistance, metastasis, and immune evasion, thus suggesting their importance in GC management.

Integrin-linked kinase-frizzled 7 interaction maintains cancer stem cells to drive platinum resistance in ovarian cancer

BACKGROUND

Platinum-based chemotherapy regimens are a mainstay in the management of ovarian cancer (OC), but emergence of chemoresistance poses a significant clinical challenge. The persistence of ovarian cancer stem cells (OCSCs) at the end of primary treatment contributes to disease recurrence. Here, we hypothesized that the extracellular matrix protects CSCs during chemotherapy and supports their tumorigenic functions by activating integrin-linked kinase (ILK), a key enzyme in drug resistance.

METHODS

TCGA datasets and OC models were investigated using an integrated proteomic and gene expression analysis and examined ILK for correlations with chemoresistance pathways and clinical outcomes. Canonical Wnt pathway components, pro-survival signaling, and stemness were examined using OC models. To investigate the role of ILK in the OCSC-phenotype, a novel pharmacological inhibitor of ILK in combination with carboplatin was utilized in vitro and in vivo OC models.

RESULTS

In response to increased fibronectin secretion and integrin β1 clustering, aberrant ILK activation supported the OCSC phenotype, contributing to OC spheroid proliferation and reduced response to platinum treatment. Complexes formed by ILK with the Wnt receptor frizzled 7 (Fzd7) were detected in tumors and correlated with metastatic progression. Moreover, TCGA datasets confirmed that combined expression of ILK and Fzd7 in high grade serous ovarian tumors is correlated with reduced response to chemotherapy and poor patient outcomes. Mechanistically, interaction of ILK with Fzd7 increased the response to Wnt ligands, thereby amplifying the stemness-associated Wnt/β-catenin signaling. Notably, preclinical studies showed that the novel ILK inhibitor compound 22 (cpd-22) alone disrupted ILK interaction with Fzd7 and CSC proliferation as spheroids. Furthermore, when combined with carboplatin, this disruption led to sustained AKT inhibition, apoptotic damage in OCSCs and reduced tumorigenicity in mice.

CONCLUSIONS

This "outside-in" signaling mechanism is potentially actionable, and combined targeting of ILK-Fzd7 may lead to new therapeutic approaches to eradicate OCSCs and improve patient outcomes.

Extracellular vesicles in non-small cell lung cancer stemness and clinical applications

Non-small cell lung carcinoma (NSCLC) accounts for 85% of lung cancers, the leading cause of cancer associated deaths in the US and worldwide. Within NSCLC tumors, there is a subpopulation of cancer cells termed cancer stem cells (CSCs) which exhibit stem-like properties that drive NSCLC progression, metastasis, relapse, and therapeutic resistance. Extracellular vesicles (EVs) are membrane-bound nanoparticles secreted by cells that carry vital messages for short- and long-range intercellular communication. Numerous studies have implicated NSCLC CSC-derived EVs in the factors associated with NSCLC lethality. In this review, we have discussed mechanisms of EV-directed cross-talk between CSCs and cells of the tumor microenvironment that promote stemness, tumor progression and metastasis in NSCLC. The mechanistic studies discussed herein have provided insights for developing novel NSCLC diagnostic and prognostic biomarkers and strategies to therapeutically target the NSCLC CSC niche.

Dual-inhibition of NAMPT and PAK4 induces anti-tumor effects in 3D-spheroids model of platinum-resistant ovarian cancer

Ovarian cancer follows a characteristic progression pattern, forming multiple tumor masses enriched with cancer stem cells (CSCs) within the abdomen. Most patients develop resistance to standard platinum-based drugs, necessitating better treatment approaches. Targeting CSCs by inhibiting NAD+ synthesis has been previously explored. Nicotinamide phosphoribosyltransferase (NAMPT), which is the rate limiting enzyme in the salvage pathway for NAD+ synthesis is an attractive drug target in this pathway. KPT-9274 is an innovative drug targeting both NAMPT and p21 activated kinase 4 (PAK4). However, its effectiveness against ovarian cancer has not been validated. Here, we show the efficacy and mechanisms of KPT-9274 in treating 3D-cultured spheroids that are resistant to platinum-based drugs. In these spheroids, KPT-9274 not only inhibited NAD+ production in NAMPT-dependent cell lines, but also suppressed NADPH and ATP production, indicating reduced mitochondrial function. It also downregulated of inflammation and DNA repair-related genes. Moreover, the compound reduced PAK4 activity by altering its mostly cytoplasmic localization, leading to NAD+-dependent decreases in phosphorylation of S6 Ribosomal protein, AKT, and β-Catenin in the cytoplasm. These findings suggest that KPT-9274 could be a promising treatment for ovarian cancer patients who are resistant to platinum drugs, emphasizing the need for precision medicine to identify the specific NAD+ producing pathway that a tumor relies upon before treatment.

Ginseng-derived compounds as potential anticancer agents targeting cancer stem cells

Cancer stem cells (CSCs) are a rare subpopulation of cancer cells that exhibit stem cell-like characteristics, including self-renewal and differentiation in a multi-stage lineage state via symmetric or asymmetric division, causing tumor initiation, heterogeneity, progression, and recurrence and posing a major challenge to current anticancer therapy. Despite the importance of CSCs in carcinogenesis and cancer progression, currently available anticancer therapeutics have limitations for eradicating CSCs. Moreover, the efficacy and therapeutic windows of currently available anti-CSC agents are limited, suggesting the necessity to optimize and develop a novel anticancer agent targeting CSCs. Ginseng has been traditionally used for enhancing immunity and relieving fatigue. As ginseng's long history of use has demonstrated its safety, it has gained attention for its potential pharmacological properties, including anticancer effects. Several studies have identified the bioactive principles of ginseng, such as ginseng saponin (ginsenosides) and non-saponin compounds (e.g., polysaccharides, polyacetylenes, and phenolic compounds), and their pharmacological activities, including antioxidant, anticancer, antidiabetic, antifatigue, and neuroprotective effects. Notably, recent reports have shown the potential of ginseng-derived compounds as anti-CSC agents. This review investigates the biology of CSCs and efforts to utilize ginseng-derived components for cancer treatment targeting CSCs, highlighting their role in overcoming current therapeutic limitations.

Three-Dimensional Tumor Models to Study Cancer Stemness-Mediated Drug Resistance

Solid tumors often contain genetically different populations of cancer cells, stromal cells, various structural and soluble proteins, and other soluble signaling molecules. The American Cancer society estimated 1,958,310 new cancer cases and 609,820 cancer deaths in the United States in 2023. A major barrier against successful treatment of cancer patients is drug resistance. Gain of stem cell-like states by cancer cells under drug pressure or due to interactions with the tumor microenvironment is a major mechanism that renders therapies ineffective. Identifying approaches to target cancer stem cells is expected to improve treatment outcomes for patients. Most of our understanding of drug resistance and the role of cancer stemness is from monolayer cell cultures. Recent advances in cell culture technologies have enabled developing sophisticated three-dimensional tumor models that facilitate mechanistic studies of cancer drug resistance. This review summarizes the role of cancer stemness in drug resistance and highlights the various tumor models that are used to discover the underlying mechanisms and test potentially novel therapeutics.

Cancer Stem Cells from Definition to Detection and Targeted Drugs

Cancers remain the second leading cause of mortality in the world. Preclinical and clinical studies point an important role of cancer/leukaemia stem cells (CSCs/LSCs) in the colonisation at secondary organ sites upon metastatic spreading, although the precise mechanisms for specific actions are still not fully understood. Reviewing the present knowledge on the crucial role of CSCs/LSCs, their plasticity, and population heterogeneity in treatment failures in cancer patients is timely. Standard chemotherapy, which acts mainly on rapidly dividing cells, is unable to adequately affect CSCs with a low proliferation rate. One of the proposed mechanisms of CSC resistance to anticancer agents is the fact that these cells can easily shift between different phases of the cell cycle in response to typical cell stimuli induced by anticancer drugs. In this work, we reviewed the recent studies on CSC/LSC alterations associated with disease recurrence, and we systematised the functional assays, markers, and novel methods for CSCs screening. This review emphasises CSCs' involvement in cancer progression and metastasis, as well as CSC/LSC targeting by synthetic and natural compounds aiming at their elimination or modulation of stemness properties.

Advancing cancer theranostics through biomimetics: A comprehensive review

Nanotheranostics, especially those employing biomimetic approaches, are of substantial interest for molecular imaging and cancer therapy. The incorporation of diagnostics and therapeutics, known as cancer theranostics, represents a promising strategy in modern oncology. Biomimetics, inspired by nature, offers a multidisciplinary avenue with potential in advancing cancer theranostics. This review comprehensively analyses recent progress in biomimetics-based cancer theranostics, emphasizing its role in overcoming current treatment challenges, with a focus on breast, prostate, and skin cancers. Biomimetic approaches have been explored to address multidrug resistance (MDR), emphasizing their role in immunotherapy and photothermal therapy. The specific areas covered include biomimetic drug delivery systems bypassing MDR mechanisms, biomimetic platforms for immune checkpoint blockade, immune cell modulation, and photothermal tumor ablation. Pretargeting techniques enhancing radiotherapeutic agent uptake are discussed, along with a comprehensive review of clinical trials of global nanotheranostics. This review delves into biomimetic materials, nanotechnology, and bioinspired strategies for cancer imaging, diagnosis, and targeted drug delivery. These include imaging probes, contrast agents, and biosensors for enhanced specificity and sensitivity. Biomimetic strategies for targeted drug delivery involve the design of nanoparticles, liposomes, and hydrogels for site-specific delivery and improved therapeutic efficacy. Overall, this current review provides valuable information for investigators, clinicians, and biomedical engineers, offering insights into the latest biomimetics applications in cancer theranostics. Leveraging biomimetics aims to revolutionize cancer diagnosis, treatment, and patient outcomes.

A Stem-like Patient-Derived Ovarian Cancer Model of Platinum Resistance Reveals Dissociation of Stemness and Resistance

To understand chemoresistance in the context of cancer stem cells (CSC), a cisplatin resistance model was developed using a high-grade serous ovarian cancer patient-derived, cisplatin-sensitive sample, PDX4. As a molecular subtype-specific stem-like cell line, PDX4 was selected for its representative features, including its histopathological and BRCA2 mutation status, and exposed to cisplatin in vitro. In the cisplatin-resistant cells, transcriptomics were carried out, and cell morphology, protein expression, and functional status were characterized. Additionally, potential signaling pathways involved in cisplatin resistance were explored. Our findings reveal the presence of distinct molecular signatures and phenotypic changes in cisplatin-resistant PDX4 compared to their sensitive counterparts. Surprisingly, we observed that chemoresistance was not inherently linked with increased stemness. In fact, although resistant cells expressed a combination of EMT and stemness markers, functional assays revealed that they were less proliferative, migratory, and clonogenic-features indicative of an underlying complex mechanism for cell survival. Furthermore, DNA damage tolerance and cellular stress management pathways were enriched. This novel, syngeneic model provides a valuable platform for investigating the underlying mechanisms of cisplatin resistance in a clinically relevant context, contributing to the development of targeted therapies tailored to combat resistance in stem-like ovarian cancer.

Integrin-linked kinase-frizzled 7 interaction maintains cancer stem cells to drive platinum resistance in ovarian cancer

Background

Platinum-based chemotherapy regimens are a mainstay in the management of ovarian cancer (OC), but emergence of chemoresistance poses a significant clinical challenge. The persistence of ovarian cancer stem cells (OCSCs) at the end of primary treatment contributes to disease recurrence. Here, we hypothesized that the extracellular matrix protects CSCs during chemotherapy and supports their tumorigenic functions by activating integrin-linked kinase (ILK), a key enzyme in drug resistance.

Methods

TCGA datasets and OC models were investigated using an integrated proteomic and gene expression analysis and examined ILK for correlations with chemoresistance pathways and clinical outcomes. Canonical Wnt pathway components, pro-survival signaling, and stemness were examined using OC models. To investigate the role of ILK in the OCSC-phenotype, a novel pharmacological inhibitor of ILK in combination with carboplatin was utilized in vitro and in vivo OC models.

Results

In response to increased fibronectin (FN) secretion and integrin β1 clustering, aberrant ILK activation supported the OCSC phenotype, contributing to OC spheroid proliferation and reduced response to platinum treatment. Complexes formed by ILK with the Wnt receptor frizzled 7 (Fzd7) were detected in tumors and showed a strong correlation with metastatic progression. Moreover, TCGA datasets confirmed that combined expression of ILK and Fzd7 in high grade serous ovarian tumors is correlated with reduced response to chemotherapy and poor patient outcomes. Mechanistically, interaction of ILK with Fzd7 increased the response to Wnt ligands, thereby amplifying the stemness-associated Wnt/β-catenin signaling. Notably, preclinical studies showed that the novel ILK inhibitor compound 22 (cpd-22) alone disrupted ILK interaction with Fzd7 and CSC proliferation as spheroids. Furthermore, when combined with carboplatin, this disruption led to sustained AKT inhibition, apoptotic damage in OCSCs and reduced tumorigenicity in mice.

Conclusions

This "outside-in" signaling mechanism is potentially actionable, and combined targeting of ILK-Fzd7 may represent a new therapeutic strategy to eradicate OCSCs and improve patient outcomes.

Emerging Role of Autophagy in Governing Cellular Dormancy, Metabolic Functions, and Therapeutic Responses of Cancer Stem Cells

Tumors are composed of heterogeneous populations of dysregulated cells that grow in specialized niches that support their growth and maintain their properties. Tumor heterogeneity and metastasis are among the major hindrances that exist while treating cancer patients, leading to poor clinical outcomes. Although the factors that determine tumor complexity remain largely unknown, several genotypic and phenotypic changes, including DNA mutations and metabolic reprograming provide cancer cells with a survival advantage over host cells and resistance to therapeutics. Furthermore, the presence of a specific population of cells within the tumor mass, commonly known as cancer stem cells (CSCs), is thought to initiate tumor formation, maintenance, resistance, and recurrence. Therefore, these CSCs have been investigated in detail recently as potential targets to treat cancer and prevent recurrence. Understanding the molecular mechanisms involved in CSC proliferation, self-renewal, and dormancy may provide important clues for developing effective therapeutic strategies. Autophagy, a catabolic process, has long been recognized to regulate various physiological and pathological processes. In addition to regulating cancer cells, recent studies have identified a critical role for autophagy in regulating CSC functions. Autophagy is activated under various adverse conditions and promotes cellular maintenance, survival, and even cell death. Thus, it is intriguing to address whether autophagy promotes or inhibits CSC functions and whether autophagy modulation can be used to regulate CSC functions, either alone or in combination. This review describes the roles of autophagy in the regulation of metabolic functions, proliferation and quiescence of CSCs, and its role during therapeutic stress. The review further highlights the autophagy-associated pathways that could be used to regulate CSCs. Overall, the present review will help to rationalize various translational approaches that involve autophagy-mediated modulation of CSCs in controlling cancer progression, metastasis, and recurrence.

Novel players in the development of chemoresistance in ovarian cancer: ovarian cancer stem cells, non-coding RNA and nuclear receptors

Ovarian cancer (OC) ranks as the fifth leading factor for female mortality globally, with a substantial burden of new cases and mortality recorded annually. Survival rates vary significantly based on the stage of diagnosis, with advanced stages posing significant challenges to treatment. OC is primarily categorized as epithelial, constituting approximately 90% of cases, and correct staging is essential for tailored treatment. The debulking followed by chemotherapy is the prevailing treatment, involving platinum-based drugs in combination with taxanes. However, the efficacy of chemotherapy is hindered by the development of chemoresistance, both acquired during treatment (acquired chemoresistance) and intrinsic to the patient (intrinsic chemoresistance). The emergence of chemoresistance leads to increased mortality rates, with many advanced patients experiencing disease relapse shortly after initial treatment. This review delves into the multifactorial nature of chemoresistance in OC, addressing mechanisms involving transport systems, apoptosis, DNA repair, and ovarian cancer stem cells (OCSCs). While previous research has identified genes associated with these mechanisms, the regulatory roles of non-coding RNA (ncRNA) and nuclear receptors in modulating gene expression to confer chemoresistance have remained poorly understood and underexplored. This comprehensive review aims to shed light on the genes linked to different chemoresistance mechanisms in OC and their intricate regulation by ncRNA and nuclear receptors. Specifically, we examine how these molecular players influence the chemoresistance mechanism. By exploring the interplay between these factors and gene expression regulation, this review seeks to provide a comprehensive mechanism driving chemoresistance in OC.

The prognostic significance and clinical relevance of stem cell characteristic in bladder cancer

Background

Bladder cancer (BLCA) is a common malignant tumor of urinary system and prognostic biomarkers are needed for better clinical decision-making and patient management. Cancer stem cells (CSCs) are involved in carcinogenesis, development, metastasis and recurrence of BLCA. This study explored the prognostic and predictive value of CSCs-related genes and laid the groundwork for precision treatment development in BLCA.

Methods

The mRNA data and corresponding clinical information obtained from TCGA-BLCA cohort was used to discover biomarkers and develop CSCs-related prognostic model, which was further validated in GSE32548 and GSE32894 datasets. In addition, the association between CSCs-related risk score and therapeutic efficacy was analyzed to explore the potential predictive value of the prognostic model.

Results

We identified four CSCs-related subtypes and 900 differentially expressed genes (DEGs) among subtypes. Then the CSCs-related prognostic model was built based on 16 CSCs-related DEGs with the most significant prognostic value. Patients in the low-risk group had better overall survival than those in high-risk group (P < 0.001; HR, 0.42; 95 %CI, 0.31-0.57). Multivariable Cox analysis in training and test sets confirmed the independence of CSCs-related risk score as a prognostic factor (P < 0.05). The difference of survival between two risk groups were probably due to the significantly varied immune microenvironment based on the analysis of infiltrated immune cells. Additionally, the risk score was significantly associated with chemotherapy sensitivity and the response to anti-PD-L1 therapy (P < 0.05) which suggested a potential predictive value of CSCs-related risk model.

Conclusion

We established a risk classifier based on 16 CSCs-related genes for predicting survival in patients with BLCA. The CSCs-related risk model has both prognostic value and potential predictive value for therapeutic efficacy, which brings us closer to understanding the important role of CSCs in BLCA and may provide guidance for clinical treatment decision-making and patient management. The clinical utility of the CSCs-related risk classifier warrants further studies.

A Recipe for Successful Metastasis: Transition and Migratory Modes of Ovarian Cancer Cells

One of the characteristic features of ovarian cancer is its early dissemination. Metastasis and the invasiveness of ovarian cancer are strongly dependent on the phenotypical and molecular determinants of cancer cells. Invasive cancer cells, circulating tumor cells, and cancer stem cells, which are responsible for the metastatic process, may all undergo different modes of transition, giving rise to mesenchymal, amoeboid, and redifferentiated epithelial cells. Such variability is the result of the changing needs of cancer cells, which strive to survive and colonize new organs. This would not be possible if not for the variety of migration modes adopted by the transformed cells. The most common type of metastasis in ovarian cancer is dissemination through the transcoelomic route, but transitions in ovarian cancer cells contribute greatly to hematogenous and lymphatic dissemination. This review aims to outline the transition modes of ovarian cancer cells and discuss the migratory capabilities of those cells in light of the known ovarian cancer metastasis routes.

Targeting signaling pathways in cancer stem cells: A potential approach for developing novel anti-cancer therapeutics

Cancer stem cells (CSCs) have emerged as prime players in the intricate landscape of cancer development, progression, and resistance to traditional treatments. These unique cellular subpopulations own the remarkable capability of self-renewal and differentiation, giving rise to the diverse cellular makeup of tumors and fostering their recurrence following conventional therapies. In the quest for developing more effective cancer therapeutics, the focus has now shifted toward targeting the signaling pathways that govern CSCs behavior. This chapter underscores the significance of these signaling pathways in CSC biology and their potential as pivotal targets for the development of novel chemotherapy approaches. We delve into several key signaling pathways essential for maintaining the defining characteristics of CSCs, including the Wnt, Hedgehog, Notch, JAK-STAT, NF-κB pathways, among others, shedding light on their potential crosstalk. Furthermore, we highlight the latest advancements in CSC-targeted therapies, spanning from promising preclinical models to ongoing clinical trials. A comprehensive understanding of the intricate molecular aspects of CSC signaling pathways and their manipulation holds the prospective to revolutionize cancer treatment paradigms. This, in turn, could lead to more efficacious and personalized therapies with the ultimate goal of eradicating CSCs and enhancing overall patient outcomes. The exploration of CSC signaling pathways represents a key step towards a brighter future in the battle against cancer.

The Emerging Landscape for Combating Resistance Associated with Energy-Based Therapies via Nanomedicine

Cancer represents a serious disease with significant implications for public health, imposing substantial economic burden and negative societal consequences. Compared to conventional cancer treatments, such as surgery and chemotherapy, energy-based therapies (ET) based on athermal and thermal ablation provide distinct advantages, including minimally invasive procedures and rapid postoperative recovery. Nevertheless, due to the complex pathophysiology of many solid tumors, the therapeutic effectiveness of ET is often limited. Nanotechnology offers unique opportunities by enabling facile material designs, tunable physicochemical properties, and excellent biocompatibility, thereby further augmenting the outcomes of ET. Numerous nanomaterials have demonstrated the ability to overcome intrinsic therapeutic resistance associated with ET, leading to improved antitumor responses. This comprehensive review systematically summarizes the underlying mechanisms of ET-associated resistance (ETR) and highlights representative applications of nanoplatforms used to mitigate ETR. Overall, this review emphasizes the recent advances in the field and presents a detailed account of novel nanomaterial designs in combating ETR, along with efforts aimed at facilitating their clinical translation.

SOX2 Expression Does Not Guarantee Cancer Stem Cell-like Characteristics in Lung Adenocarcinoma

Effectively targeting cancer stemness is essential for successful cancer therapy. Recent studies have revealed that SOX2, a pluripotent stem cell factor, significantly contributes to cancer stem cell (CSC)-like characteristics closely associated with cancer malignancy. However, its contradictory impact on patient survival in specific cancer types, including lung adenocarcinoma (LUAD), underscores the need for more comprehensive research to clarify its functional effect on cancer stemness. In this study, we demonstrate that SOX2 is not universally required for the regulation of CSC-like properties in LUAD. We generated SOX2 knockouts in A549, H358, and HCC827 LUAD cells using the CRISPR/Cas9 system. Our results reveal unchanged CSC characteristics, including sustained proliferation, tumor sphere formation, invasion, migration, and therapy resistance, compared to normal cells. Conversely, SOX2 knockdown using conditional shRNA targeting SOX2, significantly reduced CSC traits. However, these loss-of-function effects were not rescued by SOX2 resistant to shRNA, underscoring the potential for SOX2 protein level-independent results in prior siRNA- or shRNA-based research. Ultimately, our findings demonstrate that SOX2 is not absolutely essential in LUAD cancer cells. This emphasizes the necessity of considering cancer subtype-dependent and context-dependent factors when targeting SOX2 overexpression as a potential therapeutic vulnerability in diverse cancers.

Biology-driven therapy advances in high-grade serous ovarian cancer

Following a period of slow progress, the completion of genome sequencing and the paradigm shift relative to the cell of origin for high grade serous ovarian cancer (HGSOC) led to a new perspective on the biology and therapeutic solutions for this deadly cancer. Experimental models were revisited to address old questions, and improved tools were generated. Additional pathways emerging as drivers of ovarian tumorigenesis and key dependencies for therapeutic targeting, in particular, VEGF-driven angiogenesis and homologous recombination deficiency, were discovered. Molecular profiling of histological subtypes of ovarian cancer defined distinct genetic events for each entity, enabling the first attempts toward personalized treatment. Armed with this knowledge, HGSOC treatment was revised to include new agents. Among them, PARP inhibitors (PARPis) were shown to induce unprecedented improvement in clinical benefit for selected subsets of patients. Research on mechanisms of resistance to PARPis is beginning to discover vulnerabilities and point to new treatment possibilities. This Review highlights these advances, the remaining challenges, and unsolved problems in the field.

Cancer cell cycle heterogeneity as a critical determinant of therapeutic resistance

Intra-tumor heterogeneity is now arguably one of the most-studied topics in tumor biology, as it represents a major obstacle to effective cancer treatment. Since tumor cells are highly diverse at genetic, epigenetic, and phenotypic levels, intra-tumor heterogeneity can be assumed as an important contributing factor to the nullification of chemotherapeutic effects, and recurrence of the tumor. Based on the role of heterogeneous subpopulations of cancer cells with varying cell-cycle dynamics and behavior during cancer progression and treatment; herein, we aim to establish a comprehensive definition for adaptation of neoplastic cells against therapy. We discuss two parallel and yet distinct subpopulations of tumor cells that play pivotal roles in reducing the effects of chemotherapy: "resistant" and "tolerant" populations. Furthermore, this review also highlights the impact of the quiescent phase of the cell cycle as a survival mechanism for cancer cells. Beyond understanding the mechanisms underlying the quiescence, it provides an insightful perspective on cancer stem cells (CSCs) and their dual and intertwined functions based on their cell cycle state in response to treatment. Moreover, CSCs, epithelial-mesenchymal transformed cells, circulating tumor cells (CTCs), and disseminated tumor cells (DTCs), which are mostly in a quiescent state of the cell cycle are proved to have multiple biological links and can be implicated in our viewpoint of cell cycle heterogeneity in tumors. Overall, increasing our knowledge of cell cycle heterogeneity is a key to identifying new therapeutic solutions, and this emerging concept may provide us with new opportunities to prevent the dreadful cancer recurrence.

eIF4E1b is a non-canonical eIF4E protecting maternal dormant mRNAs

Maternal mRNAs are essential for protein synthesis during oogenesis and early embryogenesis. To adapt translation to specific needs during development, maternal mRNAs are translationally repressed by shortening the polyA tails. While mRNA deadenylation is associated with decapping and degradation in somatic cells, maternal mRNAs with short polyA tails are stable. Here we report that the germline-specific eIF4E paralog, eIF4E1b, is essential for zebrafish oogenesis. eIF4E1b localizes to P-bodies in zebrafish embryos and binds to mRNAs with reported short or no polyA tails, including histone mRNAs. Loss of eIF4E1b results in reduced histone mRNA levels in early gonads, consistent with a role in mRNA storage. Using mouse and human eIF4E1Bs (in vitro) and zebrafish eIF4E1b (in vivo), we show that unlike canonical eIF4Es, eIF4E1b does not interact with eIF4G to initiate translation. Instead, eIF4E1b interacts with the translational repressor eIF4ENIF1, which is required for eIF4E1b localization to P-bodies. Our study is consistent with an important role of eIF4E1b in regulating mRNA dormancy and provides new insights into fundamental post-transcriptional regulatory principles governing early vertebrate development.

Predominant factors influencing reactive oxygen species in cancer stem cells

Reactive oxygen species (ROS) and its related signaling pathways and regulating molecules play a major role in the growth and development of cancer stem cells. The concept of ROS and cancer stem cells (CSCs) has been gaining much attention since the past decade and the evidence show that these CSCs possess robust self-renewal and tumorigenic potential and are resistant to conventional chemo- and radiotherapy and believed to be responsible for tumor progression, metastasis, and recurrence. It seems reasonable to say that cancer can be cured only if the CSCs are eradicated. ROS are Janus-faced molecules that can regulate cellular physiology as well as induce cytotoxicity, depending on the magnitude, duration, and site of generation. Unlike normal cancer cells, CSCs expel ROS efficiently by upregulating ROS scavengers. This unique redox regulation in CSCs protects them from ROS-mediated cell death and nullifies the effect of radiation, leading to chemoresistance and radioresistance. However, how these CSCs control ROS production by scavenging free radicals and how they maintain low levels of ROS is a challenging to understand and these attributes make CSCs as prime therapeutic targets. Here, we summarize the mechanisms of redox regulation in CSCs, with a focus on therapy resistance, its various pathways and microRNAs regulation, and the potential therapeutic implications of manipulating the ROS levels to eradicate CSCs. A better understanding of these molecules, their interactions in the CSCs may help us to adopt proper control and treatment measures.

Cancer stem cells: a target for overcoming therapeutic resistance and relapse

Cancer stem cells (CSCs) are a small subset of cells in cancers that are thought to initiate tumorous transformation and promote metastasis, recurrence, and resistance to treatment. Growing evidence has revealed the existence of CSCs in various types of cancers and suggested that CSCs differentiate into diverse lineage cells that contribute to tumor progression. We may be able to overcome the limitations of cancer treatment with a comprehensive understanding of the biological features and mechanisms underlying therapeutic resistance in CSCs. This review provides an overview of the properties, biomarkers, and mechanisms of resistance shown by CSCs. Recent findings on metabolic features, especially fatty acid metabolism and ferroptosis in CSCs, are highlighted, along with promising targeting strategies. Targeting CSCs is a potential treatment plan to conquer cancer and prevent resistance and relapse in cancer treatment.

The Role of Cancer Stem Cell Markers in Ovarian Cancer

Ovarian cancer is the most lethal gynaecological cancer and the eighth most common female cancer. The early diagnosis of ovarian cancer remains a clinical problem despite the significant development of technology. Nearly 70% of patients with ovarian cancer are diagnosed with stages III-IV metastatic disease. Reliable diagnostic and prognostic biomarkers are currently lacking. Ovarian cancer recurrence and resistance to chemotherapy pose vital problems and translate into poor outcomes. Cancer stem cells appear to be responsible for tumour recurrence resulting from chemotherapeutic resistance. These cells are also crucial for tumour initiation due to the ability to self-renew, differentiate, avoid immune destruction, and promote inflammation and angiogenesis. Studies have confirmed an association between CSC occurrence and resistance to chemotherapy, subsequent metastases, and cancer relapses. Therefore, the elimination of CSCs appears important for overcoming drug resistance and improving prognoses. This review focuses on the expression of selected ovarian CSC markers, including CD133, CD44, CD24, CD117, and aldehyde dehydrogenase 1, which show potential prognostic significance. Some markers expressed on the surface of CSCs correlate with clinical features and can be used for the diagnosis and prognosis of ovarian cancer. However, due to the heterogeneity and plasticity of CSCs, the determination of specific CSC phenotypes is difficult.

Applications of Innovation Technologies for Personalized Cancer Medicine: Stem Cells and Gene-Editing Tools

Personalized medicine is a new approach toward safer and even cheaper treatments with minimal side effects and toxicity. Planning a therapy based on individual properties causes an effective result in a patient's treatment, especially in a complex disease such as cancer. The benefits of personalized medicine include not only early diagnosis with high accuracy but also a more appropriate and effective therapeutic approach based on the unique clinical, genetic, and epigenetic features and biomarker profiles of a specific patient's disease. In order to achieve personalized cancer therapy, understanding cancer biology plays an important role. One of the crucial applications of personalized medicine that has gained consideration more recently due to its capability in developing disease therapy is related to the field of stem cells. We review various applications of pluripotent, somatic, and cancer stem cells in personalized medicine, including targeted cancer therapy, cancer modeling, diagnostics, and drug screening. CRISPR-Cas gene-editing technology is then discussed as a state-of-the-art biotechnological advance with substantial impacts on medical and therapeutic applications. As part of this section, the role of CRISPR-Cas genome editing in recent cancer studies is reviewed as a further example of personalized medicine application.

Defining the Role of Metastasis-Initiating Cells in Promoting Carcinogenesis in Ovarian Cancer

Ovarian cancer is the deadliest gynecological malignancy with a high prevalence of transcoelomic metastasis. Metastasis is a multi-step process and only a small percentage of cancer cells, metastasis-initiating cells (MICs), have the capacity to finally establish metastatic lesions. These MICs maintain a certain level of stemness that allows them to differentiate into other cell types with distinct transcriptomic profiles and swiftly adapt to external stresses. Furthermore, they can coordinate with the microenvironment, through reciprocal interactions, to invade and establish metastases. Therefore, identifying, characterizing, and targeting MICs is a promising strategy to counter the spread of ovarian cancer. In this review, we provided an overview of OC MICs in the context of characterization, identification through cell surface markers, and their interactions with the metastatic niche to promote metastatic colonization.

Profiling ovarian cancer tumor and microenvironment during disease progression for cell-based immunotherapy design

Ovarian cancer (OC) is highly lethal due to late detection and frequent recurrence. Initial treatments, comprising surgery and chemotherapy, lead to disease remission but are invariably associated with subsequent relapse. The identification of novel therapies and an improved understanding of the molecular and cellular characteristics of OC are urgently needed. Here, we conducted a comprehensive analysis of primary tumor cells and their microenvironment from 16 chemonaive and 10 recurrent OC patient samples. Profiling OC tumor biomarkers allowed for the identification of potential molecular targets for developing immunotherapies, while profiling the microenvironment yielded insights into its cellular composition and property changes between chemonaive and recurrent samples. Notably, we identified CD1d as a biomarker of the OC microenvironment and demonstrated its targeting by invariant natural killer T (iNKT) cells. Overall, our study presents a comprehensive immuno-profiling of OC tumor and microenvironment during disease progression, guiding the development of immunotherapies for OC treatment, especially for recurrent disease.

miR-134-3p driven by anisomycin impairs ovarian cancer stem cell activity through inhibiting GPR137 expression

Background: Ovarian cancer recurrence and metastasis are predominantly attributed to ovarian cancer stem cells; however, the mechanism by which anisomycin regulates human ovarian cancer stem cells (HuOCSCs) remains unclear. Methods: cDNA microArray was used to screen microRNAs (miRNAs) targeted by anisomycin, and RT-qPCR validated the miRNA targets. TargetScan database, GO enrichment analysis, and RT-qPCR, accompanied by a fluorescent reporter system, were employed to verify the miRNA target genes. In vitro experimental cell proliferation inhibition assay, flow cytometry, Transwell, angiogenesis assay, and in vivo transplantation tumor assay were implemented to assess the ability of the overexpressed miRNAs to hinder HuOCSC activity. Western blot, RT-qPCR, and immunofluorescence were applied to measure the transcriptional and protein-level expression of the miRNA target genes and their related genes. Bioinformatic analysis predicted and deciphered the role of the miRNA target genes and related genes in the development and prognosis of ovarian cancer. Results: The expression levels of multiple DLK1-DIO3 imprinted microRNA cluster members were altered by anisomycin, among which miR-134-3p expression was most significantly elevated. miR-134-3p overexpression significantly suppressed HuOCSC activity. The screening and validation of target genes uncovered that miR-134-3p was able to markedly suppress GPR137 expression. Additionally, miR-134-3p regulated the cytoskeleton, migration-related protein in the NDEL1/DYNEIN/TUBA1A axis through targeting GPR137. Bioinformatics prediction unveiled a close association of GPR137, NDEL1, DYNC1H1, and TUBA1A with ovarian cancer development and prognosis. Conclusions: The activity of HuOCSCs may be compromised by anisomycin through the regulation of miR-134-3p, which inhibits the GPR137/NDEL1/DYNEIN/TUBA1A axis.

Tumor-Associated Macrophages Expand Chemoresistant, Ovarian Cancer Stem-Like Cells

The persistence of ovarian cancer stem-like cells (OvCSCs) after chemotherapy resistance has been implicated in relapse. However, the ability of these relatively quiescent cells to produce the robust tumor regrowth necessary for relapse remains an enigma. Since normal stem cells exist in a niche, and tumor-associated macrophages (TAMs) are the highest abundance immune cell within ovarian tumors, we hypothesized that TAMs may influence OvCSC proliferation. To test this, we optimized OvCSC enrichment by sphere culture and in vitro polarization of monocytes to a TAM-like M2 phenotype. Using cocultures that permitted the exchange of only soluble factors, we found that M2 macrophages increased the proliferation of sphere cells. Longer-term exposure (5-7 days) to soluble TAM factors led to retention of some stem cell features by OvCSCs but loss of others, suggesting that TAMs may support an intermediate stemness phenotype in OvCSCs. Although TAM coculture decreased the percentage of OvCSCs surviving chemotherapy, it increased the overall number. We therefore sought to determine the influence of this interaction on chemotherapy efficacy in vivo and found that inhibiting macrophages improved chemotherapy response. Comparing the gene expression changes in OvCSCs cocultured with TAMs to publicly available patient data identified 34 genes upregulated in OvCSCs by exposure to soluble TAM factors whose expression correlates with outcome. Overall, these data suggest that TAMs may influence OvCSC proliferation and impact therapeutic response.

Cancer stem cell-derived exosome-induced metastatic cancer: An orchestra within the tumor microenvironment

Although the mechanisms as well as pathways associated with cancer stem cell (CSC) maintenance, expansion, and tumorigenicity have been extensively studied and the role of tumor cell (TC)-derived exosomes in this process is well understood, there is a paucity of research focusing specifically on the functional mechanisms of CSC-derived exosomes (CSC-Exo)/-exosomal-ncRNAs and their impact on malignancy. This shortcoming needs to be addressed, given that these vesicular and molecular components of CSCs could have a great impact on the cancer initiation, progression, and recurrence through their interaction with other key tumor microenvironment (TME) components, such as MSCs/MSC-Exo and CAFs/CAF-Exo. In particular, understanding CSCs/CSC-Exo and its crosstalk with MSCs/MSC-Exo or CAFs/CAF-Exo that are associated with the proliferation, migration, differentiation, angiogenesis, and metastasis through an enhanced process of self-renewal, chemotherapy as well as radiotherapy resistance may aid cancer treatment. This review contributes to this endeavor by summarizing the characteristic features and functional mechanisms of CSC-Exo/MSC-Exo/CAF-Exo and their mutual impact on cancer progression and therapy resistance.

Mitochondria in Cancer Stem Cells: From an Innocent Bystander to a Central Player in Therapy Resistance

Cancer continues to rank among the world's leading causes of mortality despite advancements in treatment. Cancer stem cells, which can self-renew, are present in low abundance and contribute significantly to tumor recurrence, tumorigenicity, and drug resistance to various therapies. The drug resistance observed in cancer stem cells is attributed to several factors, such as cellular quiescence, dormancy, elevated aldehyde dehydrogenase activity, apoptosis evasion mechanisms, high expression of drug efflux pumps, protective vascular niche, enhanced DNA damage response, scavenging of reactive oxygen species, hypoxic stability, and stemness-related signaling pathways. Multiple studies have shown that mitochondria play a pivotal role in conferring drug resistance to cancer stem cells, through mitochondrial biogenesis, metabolism, and dynamics. A better understanding of how mitochondria contribute to tumorigenesis, heterogeneity, and drug resistance could lead to the development of innovative cancer treatments.

Functional Homologous Recombination Assay on FFPE Specimens of Advanced High-Grade Serous Ovarian Cancer Predicts Clinical Outcomes

PURPOSE

Deficiency in homologous recombination (HR) repair of DNA damage is characteristic of many high-grade serous ovarian cancers (HGSC). It is imperative to identify patients with homologous recombination-deficient (HRD) tumors as they are most likely to benefit from platinum-based chemotherapy and PARP inhibitors (PARPi). Existing methods measure historical, not necessarily current HRD and/or require high tumor cell content, which is not achievable for many patients. We set out to develop a clinically feasible assay for identifying functionally HRD tumors that can predict clinical outcomes.

EXPERIMENTAL DESIGN

We quantified RAD51, a key HR protein, in immunostained formalin-fixed, paraffin-embedded (FFPE) tumor samples obtained from chemotherapy-naïve and neoadjuvant chemotherapy (NACT)-treated HGSC patients. We defined cutoffs for functional HRD separately for these sample types, classified the patients accordingly as HRD or HR-proficient, and analyzed correlations with clinical outcomes. From the same specimens, genomics-based HRD estimates (HR gene mutations, genomic signatures, and genomic scars) were also determined, and compared with functional HR (fHR) status.

RESULTS

fHR status significantly predicted several clinical outcomes, including progression-free survival (PFS) and overall survival (OS), when determined from chemo-naïve (PFS, P < 0.0001; OS, P < 0.0001) as well as NACT-treated (PFS, P < 0.0001; OS, P = 0.0033) tumor specimens. The fHR test also identified as HRD those PARPi-at-recurrence-treated patients with longer OS (P = 0.0188).

CONCLUSIONS

We developed an fHR assay performed on routine FFPE specimens, obtained from either chemo-naïve or NACT-treated HGSC patients, that can significantly predict real-world platinum-based chemotherapy and PARPi response. See related commentary by Garg and Oza, p. 2957.

Emerging role of interactions between tumor angiogenesis and cancer stem cells

Tumor angiogenesis and cancer stem cells (CSCs) are two major hallmarks of solid tumors. They have long received attention for their critical roles in tumor progression, metastasis and recurrence. Meanwhile, plenty of evidence indicates the close association between CSCs and tumor vasculature. CSCs are proven to promote tumor angiogenesis, and the highly vascularized tumor microenvironment further maintains CSCs growth in return, thereby forming a hard-breaking vicious circle to promote tumor development. Hence, though monotherapy targeting tumor vasculature or CSCs has been extensively studied over the past decades, the poor prognosis has been limiting the clinical application. This review summarizes the crosstalk between tumor vasculature and CSCs with emphasis on small-molecule compounds and the associated biological signaling pathways. We also highlight the importance of linking tumor vessels to CSCs to disrupt the CSCs-angiogenesis vicious circle. More precise treatment regimens targeting tumor vasculature and CSCs are expected to benefit future tumor treatment development.

Cd44v6 acts as a directional responding factor in the process of transcoelomic metastasis from gastric carcinoma to Krukenberg tumor

INTRODUCTION

Due to the limited number of studies focusing on the optimal treatment of multiple Krukenberg tumor (KT)-gastric carcinoma (KT - GC), it is necessary to conduct large-scale studies to confirm the definite role of serum tumor markers in the diagnosis and prognosis of KT. Moreover, the clinical significance of variant 6 of CD44 (CD44v6) in transcoelomic metastasis should be considered.

AREAS COVERED

This review covers molecular pre-cancer diagnosis, gastric carcinoma metastasis, and anti-cancer treatments. Additionally, gastrointestinal cancer metastasis is a key area for improvement.

EXPERT OPINION

The detection of CD44v6 differs in the World Health Organization Classification of Gastric Adenocarcinoma, the Lauren Classification of Gastric Adenocarcinoma, and the anatomic location of gastric adenocarcinoma. The results were compared among the three groups. The mechanism of gastric adenocarcinoma metastasis still requires further elucidation. CD44v6 molecular detection helps clarify the pre-cancer diagnosis of KT before seeding. If subsequent studies confirm its role as a signaling molecule, it could pave the way for new research directions in clinical practice; however, additional academic confirmation is necessary.

Molecular Mechanisms of Tumor Cell Stemness Modulation during Formation of Spheroids

Cancer stem cells (CSCs), their properties and interaction with microenvironment are of interest in modern medicine and biology. There are many studies on the emergence of CSCs and their involvement in tumor pathogenesis. The most important property inherent to CSCs is their stemness. Stemness combines ability of the cell to maintain its pluripotency, give rise to differentiated cells, and interact with environment to maintain a balance between dormancy, proliferation, and regeneration. While adult stem cells exhibit these properties by participating in tissue homeostasis, CSCs behave as their malignant equivalents. High tumor resistance to therapy, ability to differentiate, activate angiogenesis and metastasis arise precisely due to the stemness of CSCs. These cells can be used as a target for therapy of different types of cancer. Laboratory models are needed to study cancer biology and find new therapeutic strategies. A promising direction is three-dimensional tumor models or spheroids. Such models exhibit properties resembling stemness in a natural tumor. By modifying spheroids, it becomes possible to investigate the effect of therapy on CSCs, thus contributing to the development of anti-tumor drug test systems. The review examines the niche of CSCs, the possibility of their study using three-dimensional spheroids, and existing markers for assessing stemness of CSCs.

"DEPHENCE" system-a novel regimen of therapy that is urgently needed in the high-grade serous ovarian cancer-a focus on anti-cancer stem cell and anti-tumor microenvironment targeted therapies

Ovarian cancer, especially high-grade serous type, is the most lethal gynecological malignancy. The lack of screening programs and the scarcity of symptomatology result in the late diagnosis in about 75% of affected women. Despite very demanding and aggressive surgical treatment, multiple-line chemotherapy regimens and both approved and clinically tested targeted therapies, the overall survival of patients is still unsatisfactory and disappointing. Research studies have recently brought some more understanding of the molecular diversity of the ovarian cancer, its unique intraperitoneal biology, the role of cancer stem cells, and the complexity of tumor microenvironment. There is a growing body of evidence that individualization of the treatment adjusted to the molecular and biochemical signature of the tumor as well as to the medical status of the patient should replace or supplement the foregoing therapy. In this review, we have proposed the principles of the novel regimen of the therapy that we called the "DEPHENCE" system, and we have extensively discussed the results of the studies focused on the ovarian cancer stem cells, other components of cancer metastatic niche, and, finally, clinical trials targeting these two environments. Through this, we have tried to present the evolving landscape of treatment options and put flesh on the experimental approach to attack the high-grade serous ovarian cancer multidirectionally, corresponding to the "DEPHENCE" system postulates.

Deciphering Common Traits of Breast and Ovarian Cancer Stem Cells and Possible Therapeutic Approaches

Breast cancer (BC) and ovarian cancer (OC) are among the most common and deadly cancers affecting women worldwide. Both are complex diseases with marked heterogeneity. Despite the induction of screening programs that increase the frequency of earlier diagnosis of BC, at a stage when the cancer is more likely to respond to therapy, which does not exist for OC, more than 50% of both cancers are diagnosed at an advanced stage. Initial therapy can put the cancer into remission. However, recurrences occur frequently in both BC and OC, which are highly cancer-subtype dependent. Therapy resistance is mainly attributed to a rare subpopulation of cells, named cancer stem cells (CSC) or tumor-initiating cells, as they are capable of self-renewal, tumor initiation, and regrowth of tumor bulk. In this review, we will discuss the distinctive markers and signaling pathways that characterize CSC, their interactions with the tumor microenvironment, and the strategies they employ to evade immune surveillance. Our focus will be on identifying the common features of breast cancer stem cells (BCSC) and ovarian cancer stem cells (OCSC) and suggesting potential therapeutic approaches.

Low-dose BPA and its substitute BPS promote ovarian cancer cell stemness via a non-canonical PINK1/p53 mitophagic signaling

The environmental toxicity of bisphenol A (BPA) and its analog like bisphenol S (BPS) have drawn wide attention, but their roles in cancer progression remain controversial. Here, we investigated the effect of BPA/BPS on the development of ovarian cancer. Human internal BPA/BPS exposure levels were analyzed from NHANES 2013-2016 data. We treated human ovarian cancer cells with 0-1000 nM BPA/BPS and found that 100 nM BPA/BPS treatment significantly increased Cancer Stem Cell (CSC) markers expression including OCT4, NANOG and SOX2. Cancer cell stemness evaluation induced by BPA/BPS was notably attenuated by the knockdown of PINK1 or Mdivi-1 treatment. The activation of PINK1 initiated mitophagy by inhibiting p-p53 nuclear translocation in a non-canonical manner. In vivo studies validated that BPA/BPS-exposed mice have higher tumor metastasis incidence compared with the control group, while mitophagy inhibition blocked such a promotion effect. In addition, CSC markers such as SOX2 had been found to be overexpressed in the tumor tissues of BPA/BPS exposure group. Taken together, the findings herein first provide the evidence that environmentally relevant BPA/BPS exposure could enhance ovarian cancer cell stemness through a non-canonical PINK1/p53 mitophagic pathway, raising concerns about the potential population hazards of BPA and other bisphenol analogs.

Fatty Acid Metabolites and the Tumor Microenvironment as Potent Regulators of Cancer Stem Cell Signaling

Individual cancer cells are not equal but are organized into a cellular hierarchy in which only a rare few leukemia cells can self-renew in a manner reminiscent of the characteristic stem cell properties. The PI3K/AKT pathway functions in a variety of cancers and plays a critical role in the survival and proliferation of healthy cells under physiologic conditions. In addition, cancer stem cells might exhibit a variety of metabolic reprogramming phenotypes that cannot be completely attributed to the intrinsic heterogeneity of cancer. Given the heterogeneity of cancer stem cells, new strategies with single-cell resolution will become a powerful tool to eradicate the aggressive cell population harboring cancer stem cell phenotypes. Here, this article will provide an overview of the most important signaling pathways of cancer stem cells regarding their relevance to the tumor microenvironment and fatty acid metabolism, suggesting valuable strategies among cancer immunotherapies to inhibit the recurrence of tumors.

Novel chromobox 2 inhibitory peptide decreases tumor progression

BACKGROUND

The Polycomb Repressor Complex 1 (PRC1) is an epigenetic regulator of differentiation and development, consisting of multiple subunits including RING1, BMI1, and Chromobox. The composition of PRC1 dictates its function and aberrant expression of specific subunits contributes to several diseases including cancer. Specifically, the reader protein Chromobox2 (CBX2) recognizes the repressive modifications including histone H3 lysine 27 tri-methylation (H3K27me3) and H3 lysine 9 dimethylation (H3K9me2). CBX2 is overexpressed in several cancers compared to the non-transformed cell counterparts, it promotes both cancer progression and chemotherapy resistance. Thus, inhibiting the reader function of CBX2 is an attractive and unique anti-cancer approach.

RESEARCH DESIGN & METHODS

Compared with other CBX family members, CBX2 has a unique A/T-hook DNA binding domain that is juxtaposed to the chromodomain (CD). Using a computational approach, we constructed a homology model of CBX2 encompassing the CD and A/T hook domain. We used the model as a basis for peptide design and identified blocking peptides that are predicted to directly bind the CD and A/T-hook regions of CBX2. These peptides were tested in vitro and in vivo models.

CONCLUSION

The CBX2 blocking peptide significantly inhibited both 2D and 3D growth of ovarian cancer cells, downregulated a CBX2 target gene, and blunted tumor growth in vivo.