Overview of Cancer Stem Cells and Stemness for Community Oncologists

OCT4 and MENA immunoprofiling in salivary mucoepidermoid carcinoma

BACKGROUND

Mucoepidermoid carcinoma (MEC) emblematizes the predominant malignant salivary gland neoplasm, characterized by its heterogeneous morphological features and diverse clinical representations. The expression patterns and prognostic significance of Octamer transcription factor 4 (OCT4) and Mammalian-enabled (MENA) protein in MEC perdure are incompletely described.

METHODS

Immunohistochemical analysis was performed on 46 archival MEC specimens and 5 normal salivary-gland controls. OCT4 and MENA staining were assessed histomorphometrically and correlated with clinicopathological parameters. Statistical analysis comprised Monte Carlo and Spearman's correlation tests.

RESULTS

OCT4 revealed selective cytoplasmic immunoreactivity in intermediate and epidermoid cells, without nuclear positivity. Strong OCT4 expression predominated in low-grade (66.7%), while high-grade MEC exhibited variable immunoreactivity, with 53% showing weak expression. No significant correlation was found between OCT4 expression and clinical or pathological data. MENA showed cytoplasmic and membranous immunolocalization, with expression patterns correlated significantly with age (p = 0.015), tumor size (p = 0.012), clinical stage (p = 0.004), and histological grading (p = 0.001). Spearman's correlation analysis revealed a weak, non-significant association between OCT4 and MENA expression (r = 0.05, p = 0.744).

CONCLUSIONS

The differential expression patterns of OCT4 and MENA in MEC prognosticate distinct regulatory mechanisms. While OCT4 cytoplasmic expression may presage early involvement in carcinogenesis, MENA cellular expression portends potentially independent molecular pathways, possibly encompassing subnetworks in the Wnt/β-catenin and TGF-β signaling cascades. MENA may serve as a biomarker for predicting the aggressive behavior of MEC.

A Novel Rexinoid Agonist, UAB116, Decreases Metastatic Phenotype in Hepatoblastoma by Inhibiting the Wnt/β-Catenin Pathway via Upregulation of TRIM29

Hepatoblastoma (HB) is the most common pediatric primary liver tumor. About 20% of affected children have pulmonary metastasis at presentation. Survival rates for these children are dismal, not exceeding 25%. To study this subset of patients, we sequenced a metastatic HB cell line, HLM_2, and identified downregulation of the Liver X Receptor (LXR)/Retinoid X Receptor (RXR) pathway. LXR/RXRs function as transcriptional regulators that influence genes implicated in HB development, including the Wnt/β-catenin signaling pathway. We assessed the effects of a novel LXR/RXR agonist, UAB116, on metastatic HB, hypothesizing that this compound would affect genes governing the Wnt/β-catenin pathway, decreasing the metastatic phenotype of HLM_2 metastatic HB cells. We evaluated its effects on viability, proliferation, stemness, clonogenicity, and motility, and performed RNA sequencing to study differential gene regulation. Treatment with UAB116 for 72 h decreased HLM_2 proliferation, stemness, clonogenicity, and invasion. RNA sequencing identified an eight-fold increase in TRIM29, a gene known to inhibit β-catenin, in cells treated with UAB116. Administration of the LXR/RXR agonist, UAB116, reduces proliferation, stemness, and invasiveness of metastatic HB cells, potentially by upregulation of TRIM29, a known modulator of the Wnt/β-catenin pathway, providing support for further exploration of LXR/RXR agonism as a therapeutic strategy for metastatic HB.

Glioblastoma Stem Cells at the Nexus of Tumor Heterogeneity, Immune Evasion, and Therapeutic Resistance

Glioblastoma (GBM) is an exceedingly aggressive primary brain tumor defined by rapid growth, extensive infiltration, and resistance to standard therapies. A central factor driving these malignancies is the subpopulation of glioblastoma stem cells (GSCs), which possess self-renewal capacity, multipotency, and the ability to regenerate tumor heterogeneity. GSCs contribute to key hallmarks of GBM pathobiology, including relentless progression, resistance to chemotherapy and radiotherapy, and inevitable recurrence. GSCs exhibit distinct molecular signatures, enhanced DNA repair, and metabolic adaptations that protect them against conventional treatments. Moreover, they reside within specialized niches-such as perivascular or hypoxic microenvironments-that sustain stemness, promote immunosuppression, and facilitate angiogenesis. Recent discoveries highlight signaling pathways like Notch, Wnt/β-catenin, Hedgehog, STAT3-PARN, and factors such as TFPI2 and HML-2 as critical regulators of GSC maintenance, plasticity, and immune evasion. These findings underscore the complexity of GSC biology and their pivotal role in driving GBM heterogeneity and therapeutic failure. Emerging therapeutic strategies aim to target GSCs through multiple avenues, including surface markers, immunotherapeutics (e.g., CAR T cells), metabolic vulnerabilities, and combination regimens. Advances in patient-derived organoids, single-cell omics, and 3D co-culture models enable more accurate representation of the tumor ecosystem and personalized therapeutic approaches. Ultimately, improved understanding of GSC-specific targets and the tumor microenvironment promises more effective interventions, paving the way toward better clinical outcomes for GBM patients.

Role of noncoding RNA as a pacemaker in cancer stem cell regulation: a review article

Accumulated evidence supported the crucial role of a tiny population of cells within the tumor called cancer stem cells (CSCs) in cancer origination, and proliferation. Additionally, these cells are distinguished by their self-renewal, differentiation, and therapeutic resistance capabilities. Interestingly, many studies recorded dysregulation of different types of noncoding RNAs, such as microRNA (miRNA) and long non-coding RNA (LncRNA), in cancer cells as well as CSCs. Moreover, several studies also supported the regulation of the transcription factors and signaling pathways required for CSC progression by these noncoding RNAs. However, the exact biological functions of all these noncoding RNAs are not well understood yet. These findings are of great interest, implying usage of noncoding RNA as therapeutic tool to target these cells. In this review, we provide an insight into how noncoding RNAs regulate CSCs and how this correlation is manipulated to develop new therapies to eradicate cancer cells successfully.

FBXO32 ubiquitination of SUFU promotes progression and lenvatinib resistance in hepatocellular carcinoma via hedgehog signaling

Lenvatinib is a prevalent treatment for hepatocellular carcinoma (HCC), yet resistance to the drug significantly limits its effectiveness. This study investigates the role of FBXO32 (F-Box Protein 32) in HCC progression and lenvatinib resistance. Methods: We utilized the GSE211850 and GSE46408 datasets to identify an E3 ubiquitin ligase that is highly expressed in both lenvatinib-resistant HCC cells and HCC tissues. The expression and clinical relevance of this E3 ubiquitin ligase were further validated using lenvatinib-resistant HCC cells, online databases, and HCC clinical tissue samples. The phenotype was verified by cell and animal experiments. Techniques such as RNA sequencing, western blotting, immunofluorescence, Co-immunoprecipitation (Co‑IP), Ubiquitination, and cycloheximide (CHX) chase assay reveal the mechanism. FBXO32 is highly expressed in both lenvatinib-resistant HCC cells and HCC tissues. High FBXO32 expression correlated with increased ALT, AFP levels, larger tumors, and advanced TNM stages, serving as an independent risk factor for overall survival (OS) and recurrence-free survival (RFS). Functional assays demonstrated that FBXO32 overexpression enhanced cell proliferation, stemness, apoptosis resistance, and lenvatinib resistance, while knockdown had opposing effects. KEGG enrichment analysis indicated a link between FBXO32 and the Hedgehog signaling pathway. FBXO32-mediated degradation of SUFU, a Hedgehog pathway inhibitor, activated this pathway. Inhibiting Hedgehog signaling counteracted FBXO32's impact on HCC growth and resistance. Conclusion: FBXO32 is a critical marker for lenvatinib efficacy and HCC prognosis, suggesting that targeting FBXO32 or the Hedgehog pathway could provide innovative strategies for overcoming lenvatinib resistance in HCC.

Single-cell RNA-seq reveals diverse molecular signatures associated with Methotrexate resistance in primary central nervous system lymphoma cells

PURPOSE

Methotrexate is one of the most essential single agents in patients with primary central nervous system lymphoma (PCNSL). However, 25-50% result in relapse with a poor prognosis. Therefore, studies on methotrexate resistance are warranted to explore salvage chemotherapy for recurrent PCNSL. Single-cell sequence analysis enables the characterization of novel cell types and provides a precise understanding of cancer biology.

METHODS

Single-cell sequence analysis of parental and methotrexate-resistant PCNSL cells was performed. We used a Weighted Gene Co-expression Network Analysis to identify groups of significantly connected genes.

RESULTS

We identified consensus modules in both the HKBML and TK datasets. HLA-DRβ1, HLA-DQβ1,and SNRPG were hub genes those detected in both datasets revealed by network analysis. Cyclosporine A was selected as the candidate drug for treating methotrexate-resistant cells.

CONCLUSION

The results of the present study characterized the methotrexate resistance-related signaling pathways in cultured PCNSL cells. Overall, these results may account for variations in treatment responses and lead potential novel therapeutic strategies for patients with PCNSL.

Inhibition of TFF3 synergizes with c-MET inhibitors to decrease the CSC-like phenotype and metastatic burden in ER+HER2+ mammary carcinoma

The interaction between HER2 and ERα signaling pathways contributes to resistance to anti-estrogen and HER2-targeted therapies, presenting substantial treatment challenges in ER-positive (ER+) HER2-positive (HER2+) mammary carcinoma (MC). Trefoil Factor-3 (TFF3) has been reported to mediate resistance to both anti-estrogen and anti-HER2 targeted therapies in ER+ and ER+HER2+ MC, respectively. Herein, the function and mechanism of TFF3 in ER+HER2+ MC were delineated; and novel combinatorial therapeutic strategies were identified. Elevated expression of TFF3 promoted the oncogenicity of ER+HER2+ MC cells, including enhanced cell proliferation, survival, anchorage-independent growth, 3D growth, cancer stem cell-like (CSC-like) phenotype, migration, invasion, and xenograft growth. Targeting TFF3 with an interfering RNA plasmid or a small-molecule inhibitor (AMPC) inhibited these oncogenic characteristics, highlighting the therapeutic potential of targeting TFF3 in ER+HER2+ MC. Furthermore, a high-throughput combinatorial anti-cancer compound library screening revealed that AMPC preferentially synergized with receptor tyrosine kinase c-MET inhibitors (c-METis) to reduce cell survival and the CSC-like phenotype. The combination of AMPC and c-METis also synergistically suppressed the in vivo growth of ER+HER2+ MC cell-derived xenografts and abrogated lung metastasis. Mechanistically, TFF3 was observed to activate c-MET signaling through a positive-feedback loop to enhance the CSC-like phenotype of ER+HER2+ MC. Therefore, proof of concept is provided herein that antagonizing of TFF3 is a promising therapeutic strategy in combination with c-MET inhibition for the treatment of ER+HER2+ MC.

Dysregulation of the p53 pathway provides a therapeutic target in aggressive pediatric sarcomas with stem-like traits

PURPOSE

Pediatric sarcomas are bone and soft tissue tumors that often exhibit high metastatic potential and refractory stem-like phenotypes, resulting in poor outcomes. Aggressive sarcomas frequently harbor a disrupted p53 pathway. However, whether pediatric sarcoma stemness is associated with abrogated p53 function and might be attenuated via p53 reactivation remains unclear.

METHODS

We utilized a unique panel of pediatric sarcoma models and tumor tissue cohorts to investigate the correlation between the expression of stemness-related transcription factors, p53 pathway dysregulations, tumorigenicity in vivo, and clinicopathological features. TP53 mutation status was assessed by next-generation sequencing. Major findings were validated via shRNA-mediated silencing and functional assays. The p53 pathway-targeting drugs were used to explore the effects and selectivity of p53 reactivation against sarcoma cells with stem-like traits.

RESULTS

We found that highly tumorigenic stem-like sarcoma cells exhibit dysregulated p53, making them vulnerable to drugs that restore wild-type p53 activity. Immunohistochemistry of mouse xenografts and human tumor tissues revealed that p53 dysregulations, together with enhanced expression of the stemness-related transcription factors SOX2 or KLF4, are crucial features in pediatric osteosarcoma, rhabdomyosarcoma, and Ewing's sarcoma development. p53 dysregulation appears to be an important step for sarcoma cells to acquire a fully stem-like phenotype, and p53-positive pediatric sarcomas exhibit a high frequency of early metastasis. Importantly, reactivating p53 signaling via MDM2/MDMX inhibition selectively induces apoptosis in aggressive, stem-like Ewing's sarcoma cells while sparing healthy fibroblasts.

CONCLUSIONS

Our results indicate that restoring canonical p53 activity provides a promising strategy for developing improved therapies for pediatric sarcomas with unfavorable stem-like traits.

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

The evolutionarily conserved Wnt signaling pathway plays a central role in development and adult tissue homeostasis across species. Wnt proteins are secreted, lipid-modified signaling molecules that activate the canonical (β-catenin dependent) and non-canonical (β-catenin independent) Wnt signaling pathways. Cellular behaviors such as proliferation, differentiation, maturation, and proper body-axis specification are carried out by the canonical pathway, which is the best characterized of the known Wnt signaling paths. Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues. This includes but is not limited to embryonic, hematopoietic, mesenchymal, gut, neural, and epidermal stem cells. Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties. Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders. Not surprisingly, aberrant Wnt signaling is also associated with a wide variety of diseases, including cancer. Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation, epithelial-mesenchymal transition, and metastasis. Altogether, advances in the understanding of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway. Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt, this review aims to summarize the current knowledge of Wnt signaling in stem cells, aberrations to the Wnt pathway associated with diseases, and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

The research progress on radiation resistance of cervical cancer

Cervical carcinoma is the most prevalent gynecology malignant tumor and ranks as the fourth most common cancer worldwide, thus posing a significant threat to the lives and health of women. Advanced and early-stage cervical carcinoma patients with high-risk factors require adjuvant treatment following surgery, with radiotherapy being the primary approach. However, the tolerance of cervical cancer to radiotherapy has become a major obstacle in its treatment. Recent studies have demonstrated that radiation resistance in cervical cancer is closely associated with DNA damage repair pathways, the tumor microenvironment, tumor stem cells, hypoxia, cell cycle arrest, and epigenetic mechanisms, among other factors. The development of tumor radiation resistance involves complex interactions between multiple genes, pathways, and mechanisms, wherein each factor interacts through one or more signaling pathways. This paper provides an overview of research progress on an understanding of the mechanism underlying radiation resistance in cervical cancer.

Exercise potentially prevents colorectal cancer liver metastases by suppressing tumor epithelial cell stemness via RPS4X downregulation

BACKGROUND

Colorectal cancer (CRC) is the third most prevalent tumor globally. The liver is the most common site for CRC metastasis, and the involvement of the liver is a common cause of death in patients with late-stage CRC. Consequently, mitigating CRC liver metastasis (CRLM) is key to improving CRC prognosis and increasing survival. Exercise has been shown to be an effective method of improving the prognosis of many tumor types. However, the ability of exercise to inhibit CRLM is yet to be thoroughly investigated.

METHODS

The GSE157600 and GSE97084 datasets were used for analysis. A pan-cancer dataset which was uniformly normalized was downloaded and analyzed from the UCSC database: TCGA, TARGET, GTEx (PANCAN, n = 19,131, G = 60,499). Several advanced bioinformatics analyses were conducted, including single-cell sequencing analysis, correlation algorithm, and prognostic screen. CRC tumor microarray (TMA) as well as cell/animal experiments are used to further validate the results of the analysis.

RESULTS

The greatest variability was found in epithelial cells from the tumor group. RPS4X was generally upregulated in all types of CRC, while exercise downregulated RPS4X expression. A lowered expression of RPS4X may prolong tumor survival and reduce CRC metastasis. RPS4X and tumor stemness marker-CD44 were highly positively correlated and knockdown of RPS4X expression reduced tumor stemness both in vitro and in vivo.

CONCLUSION

RPS4X upregulation may enhance CRC stemness and increase the odds of metastasis. Exercise may reduce CRC metastasis through the regulation of RPS4X.

Machine learning determines stemness associated with simple and basal-like canine mammary carcinomas

Simple and complex carcinomas are the most common type of malignant Canine Mammary Tumors (CMTs), with simple carcinomas exhibiting aggressive behavior and poorer prognostic. Stemness is an ability associated with cancer initiation, malignancy, and therapeutic resistance, but is still few elucidated in canine mammary tumor subtypes. Here, we first validated, using CMT samples, a previously published canine one-class logistic regression machine learning algorithm (OCLR) to predict stemness (mRNAsi) in canine cancer cells. Then, using the canine mRNAsi, we observed that simple carcinomas exhibit higher stemness than complex carcinomas and other histological subtypes. Also, we confirmed that stemness is higher and associated with basal-like CMTs and with NMF2 metagene signature, a tumor-specific DNA-repair metagene signature. Using correlation analysis, we selected the top 50 genes correlated with higher stemness, and the top 50 genes correlated with lower stemness and further performed a gene set enrichment analysis to observe the biological processes enriched for these genes. Finally, we suggested two promise stemness-associated targets in CMTs, POLA2 and APEX1, especially in simple carcinomas. Thus, our work elucidates stemness as a potential mechanism behind the aggressiveness and development of canine mammary tumors, especially in simple carcinomas, describing evidence of a promising strategy to target this disease.

Significance of OCT3/4 and SOX2 antigens expression by leukemic blast cells in adult acute leukemia

OBJECTIVE

This study aimed to address the prognostic impact of SOX2 and OCT3/4 expression on adult acute leukemia patients' outcomes.

METHODS

SOX2 and OCT3/4 expression by blast cells were evaluated by flow cytometry in 80 acute leukemia patients and 8 healthy controls.

RESULTS

Baseline SOX2 and OCT3/4 expression were significantly higher in both ALL (P = < 0.001, P = 0.005 respectively) and AML patients (P < 0.001, P = 0.003 respectively) as compared to control, and decline at complete remission (CR) and elevated again at relapse. High SOX2 and OCT3/4 levels were significantly correlated with the presence of adverse risk stratification parameters.

CONCLUSION

Our findings indicated that both SOX2 and OCT3/4 could serve as biomarkers that could improve risk stratification of acute leukemia patients. Also, both SOX2 and OCT3/4 might be a therapeutic target, especially in resistant acute leukemia.

Neural Stem Cell-based Regenerative Therapy: A New Approach to Diabetes Treatment

Diabetes mellitus (DM) is the most common metabolic disorder that occurs due to the loss, or impaired function of insulin-secreting pancreatic beta cells, which are of two types - type 1 (T1D) and type 2 (T2D). To cure DM, the replacement of the destroyed pancreatic beta cells of islet of Langerhans is the most widely practiced treatment. For this, isolating neuronal stem cells and cultivating them as a source of renewable beta cells is a significant breakthrough in medicine. The functions, growth, and gene expression of insulin-producing pancreatic beta cells and neurons are very similar in many ways. A diabetic patient's neural stem cells (obtained from the hippocampus and olfactory bulb) can be used as a replacement source of beta cells for regenerative therapy to treat diabetes. The same protocol used to create functional neurons from progenitor cells can be used to create beta cells. Recent research suggests that replacing lost pancreatic beta cells with autologous transplantation of insulin-producing neural progenitor cells may be a perfect therapeutic strategy for diabetes, allowing for a safe and normal restoration of function and a reduction in potential risks and a long-term cure.

The Critical Function of microRNAs in Developing Resistance against 5- Fluorouracil in Cancer Cells

Although there have been significant advancements in cancer treatment, resistance and recurrence in patients make it one of the leading causes of death worldwide. 5-fluorouracil (5-FU), an antimetabolite agent, is widely used in treating a broad range of human malignancies. The cytotoxic effects of 5-FU are mediated by the inhibition of thymidylate synthase (TYMS/TS), resulting in the suppression of essential biosynthetic activity, as well as the misincorporation of its metabolites into RNA and DNA. Despite its huge benefits in cancer therapy, the application of 5-FU in the clinic is restricted due to the occurrence of drug resistance. MicroRNAs (miRNAs) are small, non-coding RNAs that act as negative regulators in many gene expression processes. Research has shown that changes in miRNA play a role in cancer progression and drug resistance. This review examines the role of miRNAs in 5-FU drug resistance in cancers.

Biomarkers and targeted therapy for cancer stem cells

Cancer stem cells (CSCs) are a small subpopulation of cancer cells with capabilities of self-renewal, differentiation, and tumorigenicity, and play a critical role in driving tumor heterogeneity that evolves insensitivity to therapeutics. For these reasons, extensive efforts have been made to identify and target CSCs to potentially improve the antitumor efficacy of therapeutics. While progress has been made to uncover certain CSC-associated biomarkers, the identification of CSC-specific markers, especially the targetable ones, remains a significant challenge. Here we provide an overview of the unique signaling and metabolic pathways of CSCs, summarize existing CSC biomarkers and CSC-targeted therapies, and discuss strategies to further differentiate CSCs from non-stem cancer cells and healthy cells for the development of enhanced CSC-targeted therapies.

Colibactin-producing Escherichia coli enhance resistance to chemotherapeutic drugs by promoting epithelial to mesenchymal transition and cancer stem cell emergence

Human colorectal cancers (CRCs) are readily colonized by colibactin-producing E. coli (CoPEC). CoPEC induces DNA double-strand breaks, DNA mutations, genomic instability, and cellular senescence. Infected cells produce a senescence-associated secretory phenotype (SASP), which is involved in the increase in tumorigenesis observed in CRC mouse models infected with CoPEC. This study investigated whether CoPEC, and the SASP derived from CoPEC-infected cells, impacted chemotherapeutic resistance. Human intestinal epithelial cells were infected with the CoPEC clinical 11G5 strain or with its isogenic mutant, which is unable to produce colibactin. Chemotherapeutic resistance was assessed in vitro and in a xenograft mouse model. Expressions of cancer stem cell (CSC) markers in infected cells were investigated. Data were validated using a CRC mouse model and human clinical samples. Both 11G5-infected cells, and uninfected cells incubated with the SASP produced by 11G5-infected cells exhibited an increased resistance to chemotherapeutic drugs in vitro and in vivo. This finding correlated with the induction of the epithelial to mesenchymal transition (EMT), which led to the emergence of cells exhibiting CSC features. They grew on ultra-low attachment plates, formed colonies in soft agar, and overexpressed several CSC markers (e.g. CD133, OCT-3/4, and NANOG). In agreement with these results, murine and human CRC biopsies colonized with CoPEC exhibited higher expression levels of OCT-3/4 and NANOG than biopsies devoid of CoPEC. Conclusion: CoPEC might aggravate CRCs by inducing the emergence of cancer stem cells that are highly resistant to chemotherapy.

Exploring Lin28 proteins: Unravelling structure and functions with emphasis on nervous system malignancies

Cancer and stem cells share many characteristics related to self-renewal and differentiation. Both cell types express the same critical proteins that govern cellular stemness, which provide cancer cells with the growth and survival benefits of stem cells. LIN28 is an example of one such protein. LIN28 includes two main isoforms, LIN28A and LIN28B, with diverse physiological functions from tissue development to control of pluripotency. In addition to their physiological roles, LIN28A and LIN28B affect the progression of several cancers by regulating multiple cancer hallmarks. Altered expression levels of LIN28A and LIN28B have been proposed as diagnostic and/or prognostic markers for various malignancies. This review discusses the structure and modes of action of the different LIN28 proteins and examines their roles in regulating cancer hallmarks with a focus on malignancies of the nervous system. This review also highlights some gaps in the field that require further exploration to assess the potential of targeting LIN28 proteins for controlling cancer.

Stemness signature and targeted therapeutic drugs identification for Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer and carries the worst prognosis, characterized by the lack of progesterone, estrogen, and HER2 gene expression. This study aimed to analyze cancer stemness-related gene signature to determine patients' risk stratification and prognosis feature with TNBC. Here one-class logistic regression (OCLR) algorithm was applied to compute the stemness index of TNBC patients. Cox and LASSO regression analysis was performed on stemness-index related genes to establish 16 genes-based prognostic signature, and their predictive performance was verified in TCGA and METABERIC merged data cohort. We diagnosed the expression level of prognostic genes signature in the tumor immune microenvironment, analyzed the TNBC scRNA-seq GSE176078 dataset, and further validated the expression level of prognostic genes using the HPA database. Finally, the small molecular compounds targeted at the anti-tumor effect of predictive genes were screened by molecular docking; this novel stemness-based prognostic genes signature study could facilitate the prognosis of patients with TNBC and thus provide a feasible therapeutic target for TNBC.

Cancer stemness kinase inhibitor amcasertib: a promising therapeutic agent in ovarian cancer stem and cancer cell models with different genetic profiles

Ovarian cancer, often referred to as the 'silent killer,' is a significant contributor to mortality rates. Emerging evidence implicates Nanog as a potential therapeutic target in ovarian cancer. Amcasertib (BBI-503) is an orally administered primary class stemness kinase inhibitor that effectively targets NANOG and various cancer stem cell pathways by specifically inhibiting serine-threonine stemness kinases. This study aimed to evaluate the antineoplastic effects of Nanog inhibition, a critical transcription factor associated with pluripotency and its role in ovarian cancer tumorigenesis, using the novel therapeutic agent Amcasertib in ovarian cancer cells characterized by distinct genetic profiles. The cytotoxicity of Amcasertib was assessed in both ovarian cancer and cancer stem cell models utilizing the Xelligence-RTCA system. The impact of the determined IC50 dose on apoptosis, invasion, migration, epithelial-mesenchymal transition (EMT), cell cycle progression, colony formation, and spheroid growth was evaluated using appropriate analytical techniques. Our findings revealed that Amcasertib exhibited significant antiproliferative effects and induced apoptosis in ovarian cancer and cancer stem cells. Moreover, Amcasertib caused G1 phase arrest and impeded colony formation in MDAH-2774 cells. Additionally, Amcasertib effectively inhibited spheroid growth in OVCAR-3 and OCSC cells. Notably, it demonstrated the ability to suppress invasion and migration in MDAH-2774 and OCSC cells. Furthermore, the suppression of Nanog-mediated stem cell-like features by Amcasertib was particularly pronounced in ER-negative ovarian cancer and cancer stem cells, highlighting its high anticancer efficacy in this subgroup. These results suggest that Amcasertib holds promise as a potential standalone or combination therapy agent for the treatment of ER-negative ovarian cancer.

HSP90, as a functional target antigen of a mAb 11C9, promotes stemness and tumor progression in hepatocellular carcinoma

BACKGROUND

Identification of promising targeted antigens that exhibited cancer-specific expression is a crucial step in the development of novel antibody-targeted therapies. We here aimed to investigate the anti-tumor activity of a novel monoclonal antibody (mAb) 11C9 and identify the antibody tractable target in the hepatocellular cancer stem cells (HCSCs).

METHODS

The identification of the targeted antigen was conducted using SDS-PAGE, western blot, mass spectrometry, and co-immunoprecipitation. Silence of HSP90 was induced by siRNA interference. Positive cells were sorted by fluorescence-activated cell sorting. Double-immunofluorescent (IF) staining and two-color flow cytometry detected the co-expression. Self-renewal, invasion, and drug resistance were assessed by sphere formation, matrigel-coated Transwell assay, and CCK-8 assay, respectively. Tumorigenicity was evaluated in mouse xenograft models. RNA-seq and bioinformatics analysis were performed to explore the mechanism of mAb 11C9 and potential targets.

RESULTS

MAb 11C9 inhibited invasion and self-renewal abilities of HCC cell lines and reversed the cisplatin resistance. HSP90 (~ 95 kDa) was identified as a targeted antigen of mAb 11C9. Tissue microarrays and online databases revealed that HSP90 was overexpressed in HCC and associated with a poor prognosis. FACS and double-IF staining showed the co-expression of HSP90 and CSCs markers (CD90 and ESA). In vitro and in vivo demonstrated the tumorigenic potentials of HSP90. The inhibition of HSP90 by siRNA interference or 17-AAG inhibitor both decreased the number of invasion, sphere cells, and CD90+ or ESA+ cells, as well as reversed the resistance. Bioinformatics analysis and western blot verified that HSP90 activated Wnt/β-catenin signaling.

CONCLUSIONS

The study preliminarily revealed the anti-tumor activity of mAb 11C9. More importantly, we identified HSP90 as a targeted antigen of mAb 11C9, which functions as an oncogene in phenotype shaping, stemness maintenance, and therapeutic resistance by activating Wnt/β-catenin signaling.

Mechanical manipulation of cancer cell tumorigenicity via heat shock protein signaling

Biophysical cues of rigid tumor matrix play a critical role in cancer cell malignancy. We report that stiffly confined cancer cells exhibit robust growth of spheroids in the stiff hydrogel that exerts substantial confining stress on the cells. The stressed condition activated Hsp (heat shock protein)-signal transducer and activator of transcription 3 signaling via the transient receptor potential vanilloid 4-phosphatidylinositol 3-kinase/Akt axis, thereby up-regulating the expression of the stemness-related markers in cancer cells, whereas these signaling activities were suppressed in cancer cells cultured in softer hydrogels or stiff hydrogels with stress relief or Hsp70 knockdown/inhibition. This mechanopriming based on three-dimensional culture enhanced cancer cell tumorigenicity and metastasis in animal models upon transplantation, and pharmaceutically inhibiting Hsp70 improved the anticancer efficacy of chemotherapy. Mechanistically, our study reveals the crucial role of Hsp70 in regulating cancer cell malignancy under mechanically stressed conditions and its impacts on cancer prognosis-related molecular pathways for cancer treatments.

UCHL1 acts as a prognostic factor and promotes cancer stemness in cervical squamous cell carcinoma

BACKGROUND

The incidence and death rate of cervical cancer rank fourth among female malignant tumors worldwide. A growing number of researches are devoted to exploring more effective treatment methods and cancer stem cells (CSCs) are thought to be a potential therapeutic target in cervical cancer. In our study, we focused on the expression and function of UCHL1 in cervical squamous cell carcinoma (CESC).

METHODS

We detected and the expression of UCHL1 in 134 CESC patients through immunohistochemistry and further confirm UCHL1 was a prognostic factor by univariate and multivariate analysis. Then, according to TCGA database for CESC, we found that UCHL1 expression correlated with the markers associated with CSCs (CD133, ABCG2 and SOX2). Therefore, we used western blot and spheroid formation assays to future evaluate the function of UCHL1 on cancer stemness in C-33A and SiHa cell lines. At the same time, we detected the cell proliferation, migration and invasion change by CCK-8 assay, scratch assay and transwell assay, when UCHL1 was knockdown or overexpressed. Finally, xenograft models were used to examine the effect of UCHL1 in vivo.

RESULTS

We found the expression of UCHL1 in mRNA and protein was higher in tumor than in paired normal tissue and was a prognostic factor in CESC. The UCHL1 high expression group showed a shorter survival in the overall survival. According to TCGA database, the expression of UCHL1 was correlated with CD133, ABCG2 and SOX2. The results of sphere-forming ability and CSCs related markers expression were showed UCHL1 promoted cancer stemness in CESC. Similarly, CCK-8 assay, scratch assay and transwell assay were applied to demonstrate that overexpression of UCHL1 promoted the proliferation, migration and invasion in SiHa, but when UCHL1 was knockdown in C-33A, the function of UCHL1 displayed the opposite result. Finally, knockdown UCHL1 inhibited CESC tumor propagation in xenograft models.

CONCLUSION

Our results suggest that UCHL1 is a prognostic factor and correlated with cancer stemness, proliferation, migration and invasion of CESC, which may provide a novel therapeutic strategy for CESC treatment.

Protein Posttranslational Modification in Stemness Remodeling and Its Emerging Role as a Novel Therapeutic Target in Gastrointestinal Cancers

The posttranslational modifications (PTMs) of proteins, as critical mechanisms for protein regulation, are well known to enhance the functional diversity of the proteome and dramatically participate in complicated biological processes. Recent efforts in the field of cancer biology have illustrated the extensive landscape of PTMs and their crosstalk with a wide range of pro-tumorigenic signaling pathways that decisively contribute to neoplastic transformation, tumor recurrence, and resistance to oncotherapy. Cancer stemness is an emerging concept that maintains the ability of tumor cells to self-renew and differentiate and has been recognized as the root of cancer development and therapy resistance. In recent years, the PTM profile for modulating the stemness of various tumor types has been identified. This breakthrough has shed light on the underlying mechanisms by which protein PTMs maintain cancer stemness, initiate tumor relapse, and confer resistance to oncotherapies. This review focuses on the latest knowledge of protein PTMs in reprogramming the stemness of gastrointestinal (GI) cancer. A deeper understanding of abnormal PTMs in specific proteins or signaling pathways provides an opportunity to specifically target cancer stem cells and highlights the clinical relevance of PTMs as potential biomarkers and therapeutic targets for patients with GI malignancies.

The Role of FBXW7 in Gynecologic Malignancies

The F-Box and WD Repeat Domain Containing 7 (FBXW7) protein has been shown to regulate cellular growth and act as a tumor suppressor. This protein, also known as FBW7, hCDC4, SEL10 or hAGO, is encoded by the gene FBXW7. It is a crucial component of the Skp1-Cullin1-F-box (SCF) complex, which is a ubiquitin ligase. This complex aids in the degradation of many oncoproteins, such as cyclin E, c-JUN, c-MYC, NOTCH, and MCL1, via the ubiquitin-proteasome system (UPS). The FBXW7 gene is commonly mutated or deleted in numerous types of cancer, including gynecologic cancers (GCs). Such FBXW7 mutations are linked to a poor prognosis due to increased treatment resistance. Hence, detection of the FBXW7 mutation may possibly be an appropriate diagnostic and prognostic biomarker that plays a central role in determining suitable individualized management. Recent studies also suggest that, under specific circumstances, FBXW7 may act as an oncogene. There is mounting evidence indicating that the aberrant expression of FBXW7 is involved in the development of GCs. The aim of this review is to give an update on the role of FBXW7 as a potential biomarker and also as a therapeutic target for novel treatments, particularly in the management of GCs.

An Immunohistochemical Study of Breast Cancer Brain Metastases: The Role of CD44 and AKT in the Prognosis

Breast cancer is a major health burden, and up to one-third of patients with breast cancer develop brain metastases, which are linked to a very poor prognosis. Few biomarkers are available to predict the prognosis of patients with metastases. Assessment by immunohistochemistry may be used as a tool to predict the behavior of these tumors. A retrospective transversal study including 114 patients (diagnosed between 2000 and 2016) with breast cancer brain metastases was carried out using archival biological material from 114 patients with breast cancer brain metastases. Expression of CD44, HER2, ER, PR, CA9, PDL-1, CD133, ALDH1, PTEN, AKT, PI3K, and AR markers was assessed by immunohistochemistry. The overexpression of CD44 and AKT was associated with worse overall survival ( P =0.047 and P =0,034, respectively), on univariate analysis, in the cohort of parenchymal and bone metastases; the impact of AKT expression was also evident in the parenchymal cohort on uni ( P =0.021) and multivariate analysis ( P =0.027). The remaining markers did not exhibit a statistical correlation. Immunohistochemistry markers such as CD44 and AKT may have a prognostic impact on survival in patients with breast cancer brain metastases. The conjugation with other markers may help with the stratification of patients and therapy.

Cancer Stem Cells and Prostate Cancer: A Narrative Review

Cancer stem cells (CSCs) are a small and elusive subpopulation of self-renewing cancer cells with the remarkable ability to initiate, propagate, and spread malignant disease. In the past years, several authors have focused on the possible role of CSCs in PCa development and progression. PCa CSCs typically originate from a luminal prostate cell. Three main pathways are involved in the CSC development, including the Wnt, Sonic Hedgehog, and Notch signaling pathways. Studies have observed an important role for epithelial mesenchymal transition in this process as well as for some specific miRNA. These studies led to the development of studies targeting these specific pathways to improve the management of PCa development and progression. CSCs in prostate cancer represent an actual and promising field of research.

Origin and evolution of animal multicellularity in the light of phylogenomics and cancer genetics

The rise of animals represents a major but enigmatic event in the evolutionary history of life. In recent years, numerous studies have aimed at understanding the genetic basis of this transition. However, genome comparisons of diverse animal and protist lineages suggest that the appearance of gene families that were previously considered animal specific indeed preceded animals. Animals' unicellular relatives, such as choanoflagellates, ichthyosporeans, and filastereans, demonstrate complex life cycles including transient multicellularity as well as genetic toolkits for temporal cell differentiation, cell-to-cell communication, apoptosis, and cell adhesion. This has warranted further exploration of the genetic basis underlying transitions in cellular organization. An alternative model for the study of transitions in cellular organization is tumors, which exploit physiological programs that characterize both unicellularity and multicellularity. Tumor cells, for example, switch adhesion on and off, up- or downregulate specific cell differentiation states, downregulate apoptosis, and allow cell migration within tissues. Here, we use insights from both the fields of phylogenomics and tumor biology to review the evolutionary history of the regulatory systems of multicellularity and discuss their overlap. We claim that while evolutionary biology has contributed to an increased understanding of cancer, broad investigations into tissue-normal and transformed-can also contribute the framework for exploring animal evolution.

Cancer Stem Cells and Their Possible Implications in Cervical Cancer: A Short Review

Cervical cancer (CC) is the fourth most common type of gynecological malignancy affecting females worldwide. Most CC cases are linked to infection with high-risk human papillomaviruses (HPV). There has been a significant decrease in the incidence and death rate of CC due to effective cervical Pap smear screening and administration of vaccines. However, this is not equally available throughout different societies. The prognosis of patients with advanced or recurrent CC is particularly poor, with a one-year relative survival rate of a maximum of 20%. Increasing evidence suggests that cancer stem cells (CSCs) may play an important role in CC tumorigenesis, metastasis, relapse, and chemo/radio-resistance, thus representing potential targets for a better therapeutic outcome. CSCs are a small subpopulation of tumor cells with self-renewing ability, which can differentiate into heterogeneous tumor cell types, thus creating a progeny of cells constituting the bulk of tumors. Since cervical CSCs (CCSC) are difficult to identify, this has led to the search for different markers (e.g., ABCG2, ITGA6 (CD49f), PROM1 (CD133), KRT17 (CK17), MSI1, POU5F1 (OCT4), and SOX2). Promising therapeutic strategies targeting CSC-signaling pathways and the CSC niche are currently under development. Here, we provide an overview of CC and CCSCs, describing the phenotypes of CCSCs and the potential of targeting CCSCs in the management of CC.

Epigenomic Profiling of Epithelial Ovarian Cancer Stem-Cell Differentiation Reveals GPD1 Associated Immune Suppressive Microenvironment and Poor Prognosis

Intraperitoneal metastasis is a challenging clinical scenario in epithelial ovarian cancer (EOC). As they are distinct from hematogenous metastasizing tumors, epithelial ovarian cancer cells primarily disseminate within the peritoneal cavity to form superficially invasive carcinomas. Unfavorable pharmacokinetics for peritoneal tumors and gut toxicity collectively lead to a narrow therapeutic window and therefore limit the opportunities for a favorable clinical outcome. New insights into tumor metastasis in the peritoneal microenvironment are keenly awaited to develop new therapeutic strategies. Epithelial ovarian cancer stem cell (OCSC) seeding is considered to be a critical component of the peritoneal spread. Using a unique and stepwise process of the OCSC differentiation model may provide insight into the intraperitoneal metastasis. The transcriptome and epigenome of OCSC differentiation were characterized by expression array and MethylCap-Seq. The TCGA, AOCS, and KM-Plotter databases were used to evaluate the association between survival outcomes and the methylation/expression levels of candidate genes in the EOC datasets. The STRING database was used to investigate the protein–protein interaction (PPI) for candidates and their associated genes. The infiltration level of immune cells in EOC patients and the association between clinical outcome and OCSCs differentiation genes were estimated using the TIDE and TIME2.0 algorithms. We established an EOC differentiation model using OCSCs. After an integrated transcriptomics and methylomics analysis of OCSCs differentiation, we revealed that the genes associated with earlier OCSC differentiation were better able to reflect the patient’s outcome. The OCSC differentiation genes were involved in regulating metabolism shift and the suppressive immune microenvironment. High GPD1 expression with high pro-tumorigenic immune cells (M2 macrophage, and cancer associated fibroblast) had worst survival. Moreover, we developed a methylation signature, constituted by GNPDA1, GPD1, GRASP, HOXC11, and MSLN, that may be useful for prognostic prediction in EOC. Our results revealed a novel role of epigenetic plasticity OCSC differentiation and suggested metabolic and immune intervention as a new therapeutic strategy.

Single cell mass spectrometry studies reveal metabolomic features and potential mechanisms of drug-resistant cancer cell lines

Irinotecan (Iri) is a key drug to treat metastatic colorectal cancer, but its clinical activity is often limited by de novo and acquired drug resistance. Studying the underlying mechanisms of drug resistance is necessary for developing novel therapeutic strategies. In this study, we used both regular and irinotecan-resistant (Iri-resistant) colorectal cell lines as models, and performed single cell mass spectrometry (SCMS) metabolomics studies combined with analyses from cytotoxicity assay, western blot, flow cytometry, quantitative real-time polymerase chain reaction (qPCR), and reactive oxygen species (ROS). Our SCMS results indicate that Iri-resistant cancer cells possess higher levels of unsaturated lipids compared with the regular cancer cells. In addition, multiple protein biomarkers and their corresponding mRNAs of colon cancer stem cells are overexpressed in Iri-resistance cells. Particularly, stearoyl-CoA desaturase 1 (SCD1) is upregulated with the development of drug resistance in Iri-resistant cells, whereas inhibiting the activity of SCD1 efficiently increase their sensitivity to Iri treatment. In addition, we demonstrated that SCD1 directly regulates the expression of ALDH1A1, which contributes to the cancer stemness and ROS level in Iri-resistant cell lines.

Dissecting Tumor Growth: The Role of Cancer Stem Cells in Drug Resistance and Recurrence

Simple Summary

Cancer is one of the most debated problems all over the world. Cancer stem cells are considered responsible of tumor initiation, metastasis, drug resistance, and recurrence. This subpopulation of cells has been found into the tumor bulk and showed the capacity to self-renew, differentiate, up to generate a new tumor. In the last decades, several studies have been set on the molecular mechanisms behind their specific characteristics as the Wnt/β-catenin signaling, Notch signaling, Hedgehog signaling, transcription factors, etc. The most powerful part of CSCs is represented by the niches as “promoter” of their self-renewal and “protector” from the common oncological treatment as chemotherapy and radiotherapy. In our review article we highlighted the primary mechanisms involved in CSC tumorigenesis for the setting of further targets to control the metastatic process.

Abstract

Emerging evidence suggests that a small subpopulation of cancer stem cells (CSCs) is responsible for initiation, progression, and metastasis cascade in tumors. CSCs share characteristics with normal stem cells, i.e., self-renewal and differentiation potential, suggesting that they can drive cancer progression. Consequently, targeting CSCs to prevent tumor growth or regrowth might offer a chance to lead the fight against cancer. CSCs create their niche, a specific area within tissue with a unique microenvironment that sustains their vital functions. Interactions between CSCs and their niches play a critical role in regulating CSCs’ self-renewal and tumorigenesis. Differences observed in the frequency of CSCs, due to the phenotypic plasticity of many cancer cells, remain a challenge in cancer therapeutics, since CSCs can modulate their transcriptional activities into a more stem-like state to protect themselves from destruction. This plasticity represents an essential step for future therapeutic approaches. Regarding self-renewal, CSCs are modulated by the same molecular pathways found in normal stem cells, such as Wnt/β-catenin signaling, Notch signaling, and Hedgehog signaling. Another key characteristic of CSCs is their resistance to standard chemotherapy and radiotherapy treatments, due to their capacity to rest in a quiescent state. This review will analyze the primary mechanisms involved in CSC tumorigenesis, with particular attention to the roles of CSCs in tumor progression in benign and malignant diseases; and will examine future perspectives on the identification of new markers to better control tumorigenesis, as well as dissecting the metastasis process.

The role of the STAT3 signaling transduction pathways in radioresistance

The efficacy of radiotherapy has long known to be limited by the emergence of resistance. The four Rs of radiotherapy (DNA damage repair, reoxygenation, redistribution of the cell cycle, and repopulation) are generally accepted concepts in radiobioolgy. Recent studies have strongly linked signal transducer and activator of transcription 3 (STAT3) to the regulation of cancer stemness and radioresistance. In particular, a STAT3 pathway inhibitor napabucasin, claimed to be the first cancer stemness antagonist in clinical trials, strengthens the link. However, no reviews connect STAT3 with the four Rs of radiotherapy. Herein, the evidence-based role of STAT3 in radioresistance is discussed in relation to the four Rs of radiotherapy. The proposed mechanisms include upstream and downstream effector proteins of STAT3, including FOXM1, MELK, NEK2, AKT, EZH2, and HIF1α. Downstream transcriptional products of the mechanistically-related proteins are involved in cancer stemness, anti-apoptosis, and the four Rs of radiotherapy. Utilizing selective inhibitors of the mechanistically-related proteins has shown promising antagonism of radioresistance, suggesting that the expression levels of these proteins may be biomarkers for the prediction of radiotherapeutic outcomes, and that this molecular mechanism may provide a rational axis through which to treat radioresistance.

Integrated single-cell RNA sequencing analysis reveals distinct cellular and transcriptional modules associated with survival in lung cancer

Lung adenocarcinoma (LUAD) and squamous carcinoma (LUSC) are two major subtypes of non-small cell lung cancer with distinct pathologic features and treatment paradigms. The heterogeneity can be attributed to genetic, transcriptional, and epigenetic parameters. Here, we established a multi-omics atlas, integrating 52 single-cell RNA sequencing and 2342 public bulk RNA sequencing. We investigated their differences in genetic amplification, cellular compositions, and expression modules. We revealed that LUAD and LUSC contained amplifications occurring selectively in subclusters of AT2 and basal cells, and had distinct cellular composition modules associated with poor survival of lung cancer. Malignant and stage-specific gene analyses further uncovered critical transcription factors and genes in tumor progression. Moreover, we identified subclusters with proliferating and differentiating properties in AT2 and basal cells. Overexpression assays of ten genes, including sub-cluster markers AQP5 and KPNA2, further indicated their functional roles, providing potential targets for early diagnosis and treatment in lung cancer.

Targeting CDK7 reverses tamoxifen resistance through regulating stemness in ER+ breast cancer

BACKGROUND

Although tamoxifen is the mainstay endocrine therapy for estrogen receptor-positive (ER+) breast cancer patients, the emergence of tamoxifen resistance is still the major challenge that results in treatment failure. Tamoxifen is very effective in halting breast cancer cell proliferation; nonetheless, the ability of tamoxifen to target cancer stem and progenitor cell populations (CSCs), a major key player for the emergence of tamoxifen resistance, has not been adequately investigated yet. Thus, we explored whether targeting CDK7 modulates CSCs subpopulation and tamoxifen resistance in ER+ breast cancer cells.

METHODS

Mammosphere-formation assay, stem cell biomarkers and tamoxifen sensitivity were analyzed in MCF7 tamoxifen-sensitive cell line and its resistant counterpart, LCC2, following CDK7 targeting by THZ1 or siRNA.

RESULTS

Analysis of clinically relevant data indicated that expression of stemness factor, SOX2, was positively correlated with CDK7 expression in tamoxifen-treated patients. Moreover, overexpression of the stemness gene, SOX2, was associated with shorter overall survival in those patients. Importantly, the number of CSC populations and the expression of CDK7, P-Ser118-ER-α and c-MYC were significantly higher in LCC2 cells compared with parental MCF-7 cells. Moreover, targeting CDK7 inhibited mammosphere formation, CSC-regulating genes, and CSC biomarkers expression in MCF-7 and LCC2 cells.

CONCLUSION

Our data indicate, for the first time, that CDK7-targeted therapy in ER+ breast cancer ameliorates tamoxifen resistance, at least in part, by inhibiting cancer stemness. Thus, targeting CDK7 might represent a potential approach for relieving tamoxifen resistance in ER+ breast cancer.

A review on epidermal growth factor receptor's role in breast and non-small cell lung cancer

Epithelial growth factor receptor (EGFR) is a cell surface transmembrane receptor that mediates the tyrosine signaling pathway to carry the extracellular messages inside the cell and thereby alter the function of nucleus. This leads to the generation of various protein products to up or downregulate the cellular function. It is encoded by cell erythroblastosis virus oncogene B1, so called C-erb B1/ERBB2/HER-2 gene that acts as a proto-oncogene. It belongs to the HER-2 receptor-family in breast cancer and responds best with anti-Herceptin therapy (anti-tyrosine kinase monoclonal antibody). HER-2 positive breast cancer patient exhibits worse prognosis without Herceptin therapy. Similar incidence and prognosis are reported in other epithelial neoplasms like EGFR + lung non-small cell carcinoma and glioblastoma (grade IV brain glial tumor). Present study highlights the role and connectivity of EGF with various cancers via signaling pathways, cell surface receptors mechanism, macromolecules, mitochondrial genes and neoplasm. Present study describes the EGFR associated gene expression profiling (in breast cancer and NSCLC), relation between mitrochondrial genes and carcinoma, and several in vitro and in vivo models to screen the synergistic effect of various combination treatments. According to this study, although clinical studies including targeted treatments, immunotherapies, radiotherapy, TKi-EGFR combined targeted therapy have been carried out to investigate the synergism of combination therapy; however still there is a gap to apply the scenarios of experimental and clinical studies for further developments. This review will give an idea about the transition from experimental to most advanced clinical studies with different combination drug strategies to treat cancer.

REC8 enhances stemness and promotes metastasis of colorectal cancer through BTK/Akt/β-catenin signaling pathway

Cancer/testis antigens (CTAs) are often aberrantly expressed in cancer stem cells (CSCs) which are responsible for tumor metastasis. Rec8 meiotic recombination protein (REC8), a member of CTAs, shares distinct roles in various cancers, while its contribution to CSCs and colorectal cancer (CRC) remains unclear. We found that overexpression of REC8 facilitated the migration and invasion of CRC cells (DLD-1 and SW480 cells) in vitro and promoted the liver metastasis of CRC in vivo. Moreover, REC8 is highly expressed in CRC stem-like cells and is required for the maintenance of CSC stemness. Mechanistic studies suggested that REC8 mediated through the activation of Bruton tyrosine kinase (BTK). Inhibition of BTK by ibrutinib not only suppressed the migration and invasion-promoting ability, but also declined the increased expression of p-BTK, p-Akt, β-catenin, and CSC markers upon REC8 overexpression. Importantly, high expression of REC8 in cancerous tissues was related to advanced clinical stage and lymph node metastasis of 62 CRC patients, and REC8 was enriched in the cancerous cells positive for CSC markers. Collectively, our results indicate that REC8 promotes CRC metastasis by increasing cell stemness through BTK/Akt/β-catenin pathway.

F-box proteins in cancer stemness: An emerging prognostic and therapeutic target

Cancer is a complex heterogenic disease with significant therapeutic challenges. The presence of cancer stem cells (CSCs) in cancer tissue orchestrates tumor growth, progression, and metastasis, the tumor heterogeneity, disease relapse, and therapeutic resistance. Hence, it is imperative to explore how progenitor or cancer-initiating cells acquire stemness features and reprogram different biological mechanisms to maintain their sustained oncogenicity. Interestingly, deregulation of F-box proteins (FBPs) is crucial for cancer stemness features, including drug resistance and disease relapse. In this review, we highlight recent updates on the clinical significance of targeting FBPs in cancer therapy, with emphasis on eliminating CSCs and associated therapeutic challenges. Moreover, we also discuss novel strategies for the selective elimination of CSCs by targeting FBPs.

Luteolin attenuates cancer cell stemness in PTX-resistant oesophageal cancer cells through mediating SOX2 protein stability

Cancer drug resistance is a formidable obstacle that enhances cancer stem-like cell properties, tumour metastasis and relapse. Luteolin (Lut) is a natural flavonoid with strong antitumor effects. However, the underlying mechanism(s) by which Lut protects against paclitaxel-resistant (PTX-resistant) cancer cell remains unknown. Herein, we found that Lut significantly attenuated the stem-like properties of PTX-resistant cancer cells by downregulating the expression of SOX2 protein. Additionally, further study showed that Lut could inhibit the PI3K/AKT pathway to decrease the phosphorylation level of AKT(S473) and UBR5 expression, which is an ubiquitin E3 ligase that promotes SOX2 degradation. In addition, Lut also inhibited PTX-resistant cancer cell migration and invasion by blocking epithelial-mesenchymal transition (EMT). Importantly, Lut inhibited the tumorigenic ability of oesophageal PTX-resistant cancer cells and showed no obvious toxicity in vivo. Thus, Lut has potential as a promising agent for drug-resistant oesophageal cancer therapy.

Cancer Stem Cell Traits in Tumor Spheres Derived from Primary Laryngeal Carcinoma Cell Lines

Objective

Cancer stem cells (CSCs) belong to a subpopulation of undifferentiated cells present within tumors that have the potential to regenerate, differentiate, maintenance of pluripotency, drug resistance, and tumorigenicity when transplanted into an innate host. These can influence the growth and behavior of these tumors and are used to investigate the initiation, progression, and treatment strategies of laryngeal cancer. Research on CSC science and targeted therapies were hinge on their isolation and/or enrichment procedures. The object of the study is to isolate cancer stem cells from primary laryngeal carcinoma (CSCPLC) by tumor spheres enrichment. We checked the properties of self-renewal, stemness, clonogenicity, and chemotherapeutic resistance.

Materials and Methods

We performed tumor sphere formation assay (primary, secondary, and tertiary) chemotherapy resistance by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay were performed to evaluate the CSC cells. Immunofluorescence for stem cell markers (CD133+, CD44+) and gene expression of stem cell markers for CD133+, CD44+, OCT4, SOX2, and NANOG was done using the real-time polymerase chain reaction technique.

Results

We were able to isolated CSC subpopulations from PLC cell lines by the tumor sphere method. These cells exhibited good primary, secondary, and tertiary tumor sphere formation efficiency and also disclosed a resistant index of more than 2. Immunofluorescence for stem cell markers (CD133+ and CD44+) confirms the presence of CSC. There was significantly higher mRNA expression of stem cell markers in CSC enriched subpopulations compared to the parental cell lines.

Conclusion

We conclude that tumor spheres enrichment is an efficient, economical, and reliable approach for the isolation and characterization of CSC from PLC cell lines. These cells demonstrated the properties of self-renewal, stemness, clonogenicity, and chemotherapeutic resistance.

Single-cell RNA sequencing and bioinformatics as tools to decipher cancer heterogenicity and mechanisms of drug resistance

It is well known that cancer is an aggressive disease, often associated with relapse, in many cases due to drug resistance. Cancer stem cell and clonal evolution are frequently causes of innate or acquired drug resistance. Current RNA sequencing technologies do not distinguish gene expression of different cell lineages because they are based on bulk cell studies. Single-cell RNA sequencing technologies and related bioinformatics clustering and differential expression analysis represent a turning point in cancer research. They are emerging as essential tools for dissecting tumors at single-cell resolution and represent novel tools to understand carcinogenesis and drug response. In this review, we will outline the role of these new technologies in addressing cancer heterogeneity and cell lineage-dependent drug resistance.

Establishment and characterization of novel highly aggressive HER2‑positive and triple‑negative breast cancer cell lines

Breast cancer cell lines are widely used as an in vitro system with which to study the mechanisms underlying biological and chemotherapeutic resistance. In the present study, two novel breast cancer cell lines designated as PC‑B‑142CA and PC‑B‑148CA were successfully established from HER2‑positive and triple‑negative (TN) breast cancer tissues. The cell lines were characterized by cytokeratin (CK), α‑smooth muscle actin (α‑SMA), fibroblast‑activation protein (FAP) and programmed death‑ligand 1 (PD‑L1). Cell proliferation was assessed using a colony formation assay, an MTS assay, 3‑dimensional (3‑D) spheroid and 3‑D organoid models. Wound healing and Transwell migration assays were used to explore the cell migration capability. The responses to doxorubicin (DOX) and paclitaxel (PTX) were evaluated by 3‑D spheroids. The results showed that the PC‑B‑142CA and PC‑B‑148CA cell lines were α‑SMA‑negative, FAP‑negative, CK‑positive and PD‑L1‑positive. Both cell lines were adherent with the ability of 3‑D‑multicellular spheroid and organoid formations; invadopodia were found in the spheroids/organoids of only PC‑B‑148CA. PC‑B‑142CA had a faster proliferative but lower metastatic rate compared to PC‑B‑148CA. Compared to MDA‑MB‑231, a commercial TN breast cancer cell line, PC‑B‑148CA had a similar CD44⁺/CD24^‑ stemness property (96.90%), whereas only 8.75% were found in PC‑B‑142CA. The mutations of BRCA1/2, KIT, PIK3CA, SMAD4, and TP53 were found in PC‑B‑142CA cells related to the resistance of several drugs, whereas PC‑B‑148CA had mutated BRCA2, NRAS and TP53. In conclusion, PC‑B‑142CA can serve as a novel HER2‑positive breast cancer cell line for drug resistance studies; while PC‑B‑148CA is a novel TN breast cancer cell line suitable for metastatic and stemness‑related properties.

MicroRNA-34a Alleviates Gemcitabine Resistance in Pancreatic Cancer by Repression of Cancer Stem Cell Renewal

OBJECTIVES

This study aimed to enhance the sensitivity of pancreatic ductal adenocarcinoma cells by microRNA-34a (miR-34a)-mediated targeting of Notch 1.

METHODS

Cell viability was determined by using an MTT (3-(4,5)-dimethylthiahiazo(-2)-3,5-diphenytetrazoliumromide) assay. The expression levels of miR-34a and relevant mRNAs were determined using quantitative polymerase chain reaction. Protein levels were measured by Western blotting. Cellular stemness was assessed by cell invasiveness and sphere formation assays. A transplanted tumor model was established for in vivo experiments.

RESULTS

MicroRNA-34a enhanced gemcitabine sensitivity both in vivo and in vitro. MicroRNA-34a suppressed the stemness and proliferation of pancreatic cancer stem cells. MicroRNA-34a directly associated with Notch 1, which lies upstream of epithelial-mesenchymal transition signaling pathways.

CONCLUSIONS

MicroRNA-34a sensitized pancreatic cancer cells to gemcitabine treatment by inhibiting Notch 1 signaling in pancreatic cancer stem cells, indicating that miR-34a has the potential to be developed as a novel therapeutic agent for the treatment of gemcitabine-resistant pancreatic ductal adenocarcinoma cells.

Research Progress on the Functions and Mechanism of circRNA in Cisplatin Resistance in Tumors

Cisplatin is a common chemotherapeutic drug that has been used to treat of numerous tumors, including testicular, lung, bladder, ovarian, liver and head and neck cancers. Although clinical chemotherapy based on cisplatin has shown a remarkable therapeutic effect, the resistance to cisplatin becomes increasingly obvious as a patient uses it for a prolonged period. It not only affects the prognosis of these tumors, but also causes the recurrence of cancer and decreases the overall survival rate. The development of cisplatin resistance involves several mechanisms, including DNA damage repair, ATP-binding cassette (ABC) transporter, autophagy, cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT), and other related signaling pathways. Interestingly, these mechanisms have been found to be influenced by circular RNAs (circRNAs) to regulate tumor proliferation, invasion, chemosensitivity, and other biological behaviors in the tumor microenvironment (TME). In recent years, circRNAs in cisplatin resistance in tumors, especially lung cancer and gastric cancer, have gradually drawn peoples' attention. This review summarizes recent studies on the functions and mechanisms of circRNAs in cisplatin resistance. We emphasize that circRNA can be used as a promising target gene to improve drug resistance and therapeutic efficacy.

Modulating cell differentiation in cancer models

Cancer has been traditionally viewed as a disease characterised by excessive and uncontrolled proliferation, leading to the development of cytotoxic therapies against highly proliferating malignant cells. However, tumours frequently relapse due to the presence of slow-cycling cancer stem cells eluding chemo and radiotherapy. Since these malignant stem cells are largely undifferentiated, inducing their lineage commitment has been proposed as a potential intervention strategy to deplete tumours from their most resistant components. Pro-differentiation approaches have thus far yielded clinical success in the reversion of acute promyelocytic leukaemia (APL), and new developments are fast widening their therapeutic applicability to solid carcinomas. Recent advances in cancer differentiation discussed here highlight the potential and outstanding challenges of differentiation-based approaches.

Emerging Regulatory Mechanisms Involved in Liver Cancer Stem Cell Properties in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the predominant form of primary liver cancer and one of the leading causes of cancer-related deaths worldwide. A growing body of evidence supports the hypothesis that HCC is driven by a population of cells called liver cancer stem cells (LCSCs). LCSCs have been proposed to contribute to malignant HCC progression, including promoting tumor occurrence and growth, mediating tumor metastasis, and treatment resistance, but the regulatory mechanism of LCSCs in HCC remains unclear. Understanding the signaling pathways responsible for LCSC maintenance and survival may provide opportunities to improve patient outcomes. Here, we review the current literature about the origin of LCSCs and the niche composition, describe the current evidence of signaling pathways that mediate LCSC stemness, then highlight several mechanisms that modulate LCSC properties in HCC progression, and finally, summarize the new developments in therapeutic strategies targeting LCSCs markers and regulatory pathways.

Gastric Cancer Stem Cells: A Glimpse on Metabolic Reprogramming

Gastric cancer (GC) is one of the most widespread causes of cancer-related death worldwide. Recently, emerging implied that gastric cancer stem cells (GCSCs) play an important role in the initiation and progression of GC. This subpopulation comprises cells with several features, such as self-renewal capability, high proliferating rate, and ability to modify their metabolic program, which allow them to resist current anticancer therapies. Metabolic pathway intermediates play a pivotal role in regulating cell differentiation both in tumorigenesis and during normal development. Thus, the dysregulation of both anabolic and catabolic pathways constitutes a significant opportunity to target GCSCs in order to eradicate the tumor progression. In this review, we discuss the current knowledge about metabolic phenotype that supports GCSC proliferation and we overview the compounds that selectively target metabolic intermediates of CSCs that can be used as a strategy in cancer therapy.

Alternative splicing associated with cancer stemness in kidney renal clear cell carcinoma

Backgroud

Cancer stemness is associated with metastases in kidney renal clear cell carcinoma (KIRC) and negatively correlates with immune infiltrates. Recent stemness evaluation methods based on the absolute expression have been proposed to reveal the relationship between stemness and cancer. However, we found that existing methods do not perform well in assessing the stemness of KIRC patients, and they overlooked the impact of alternative splicing. Alternative splicing not only progresses during the differentiation of stem cells, but also changes during the acquisition of the stemness features of cancer stem cells. There is an urgent need for a new method to predict KIRC-specific stemness more accurately, so as to provide help in selecting treatment options.

Methods

The corresponding RNA-Seq data were obtained from the The Cancer Genome Atlas (TCGA) data portal. We also downloaded stem cell RNA sequence data from the Progenitor Cell Biology Consortium (PCBC) Synapse Portal. Independent validation sets with large sample size and common clinic pathological characteristics were obtained from the Gene Expression Omnibus (GEO) database. we constructed a KIRC-specific stemness prediction model using an algorithm called one-class logistic regression based on the expression and alternative splicing data to predict stemness indices of KIRC patients, and the model was externally validated. We identify stemness-associated alternative splicing events (SASEs) by analyzing different alternative splicing event between high- and low- stemness groups. Univariate Cox and multivariable logistic regression analysisw as carried out to detect the prognosis-related SASEs respectively. The area under curve (AUC) of receiver operating characteristic (ROC) was performed to evaluate the predictive values of our model.

Results

Here, we constructed a KIRC-specific stemness prediction model with an AUC of 0.968,and to provide a user-friendly interface of our model for KIRC stemness analysis, we have developed KIRC Stemness Calculator and Visualization (KSCV), hosted on the Shiny server, can most easily be accessed via web browser and the url https://jiang-lab.shinyapps.io/kscv/. When applied to 605 KIRC patients, our stemness indices had a higher correlation with the gender, smoking history and metastasis of the patients than the previous stemness indices, and revealed intratumor heterogeneity at the stemness level. We identified 77 novel SASEs by dividing patients into high- and low- stemness groups with significantly different outcome and they had significant correlations with expression of 17 experimentally validated splicing factors. Both univariate and multivariate survival analysis demonstrated that SASEs closely correlated with the overall survival of patients.

Conclusions

Basing on the stemness indices, we found that not only immune infiltration but also alternative splicing events showed significant different at the stemness level. More importantly, we highlight the critical role of these differential alternative splicing events in poor prognosis, and we believe in the potential for their further translation into targets for immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08470-8.

EMT and Cancer Cell Stemness Associated With Chemotherapeutic Resistance in Esophageal Cancer

Drug resistance often occurs after chemotherapy in esophageal cancer patients, leading to cancer metastasis and recurrence. However, the relationship among cancer cell migration, recurrence and drug resistance in esophageal cancer drug-resistant cells has not been clearly explained. In this study, we constructed paclitaxel (PTX)-resistant esophageal cancer cells to explore the causes of drug resistance and poor prognosis after chemotherapy in esophageal cancer. Colony formation assay was used to evaluate the difference of colony formation between parental cells and drug resistance cells. Microsphere formation assay was used to examine the phenotype of stem cells. Wound healing and Transwell assays were used to detect the migration ability of drug-resistant cells. Western blotting and immunofluorescence assays were used to explore the mechanisms. Finally, we used nude mouse xenograft model to explore the tumor characteristics and the expression of relative proteins to verify our findings in vivo. Our study demonstrated that the cancer cell stemness characteristics exist in drug-resistant esophageal cancer cells, that expressed the biomarkers of stem cells and were prone to epithelial-mesenchymal transition (EMT). Our results suggested that the expression of EMT biomarkers and stemness-related proteins increased in esophageal cancer cells after continuously using chemotherapeutic drugs for a period of time. This study indicated that simultaneously targeting EMT and stemness could be a better strategy for the treatment of esophageal cancer drug resistance.