Oct4 confers stemness and radioresistance to head and neck squamous cell carcinoma by regulating the homologous recombination factors PSMC3IP and RAD54L

Do PGCCs in Solid Tumors Appear Due to Treatment-related Stress or Clonal Expansion of CSCs that Survive Oncotherapy?

Dedifferentiation of epithelial cells during epithelial-mesenchymal transition (EMT) results in circulating tumor cells (CTCs) that are mobilized singly or in clusters in association with blood cells and results in metastasis. However, lineage tracing studies have failed to delineate any role of EMT during metastasis. Research is also focused on polyploid giant cancer cells (PGCCs) in solid tumors which appear in response to oncotherapy-related stress for their role in metastasis. But how to explain PGCCs role in metastatic tumors in treatment-naïve patients? Studies done using mouse models and clinical samples suggest that cancer initiates due to dysfunctions of tissue-resident, pluripotent very small embryonic-like stem cells (VSELs). VSELs are the most primitive and pluripotent stem cells that exist at top of cellular hierarchy in multiple tissues. They are normally quiescent and undergo asymmetrical cell divisions to give rise to two cells of different sizes and fates including smaller cells to self-renew and bigger tissue-specific progenitors. Progenitors undergo symmetrical cell divisions and clonal expansion (rapid proliferation, endoduplication with incomplete cytokinesis) to form giant cells that further breakdown and differentiate into tissue-specific cell types. Oncotherapy destroys actively dividing cells, but CSCs survive. We hypothesize that excessive self-renewal and clonal expansion of cancer stem cells (CSCs, dysfunctional VSELs) result in multinucleated giant cells (PGCCs) that accumulate as further differentiation into tissue-specific cell types is blocked in cancerous conditions. PGCCS are being reported by multiple groups whereas CSCs remain elusive due to small size and low abundance and actually contribute to both cancer initiation and metastasis.

Multifaceted roles of OCT4 in tumor microenvironment: biology and therapeutic implications

OCT4 (Octamer-binding transcription factor 4, encoded by the POU5F1 gene) is a master transcription factor for maintaining the self-renewal and pluripotency of pluripotent stem cells, as well as a pioneer factor regulating epigenetics-driven cell reprogramming and cell fate conversion. It is also detected in a variety of cancer tissues and particularly in a small subpopulation of cancer cells known as cancer stem cells (CSCs). Accumulating evidence has revealed that CSCs are a dynamic population, exhibiting shift between multipotency and differentiation states, or quiescence and proliferation states. Such cellular plasticity of CSCs is profoundly influenced by dynamic interplay between CSCs and the tumor microenvironment (TME). Here, we review recent evidence showing that OCT4 expressed in CSCs plays a multifaceted role in shaping the TME by interacting with the cellular TME components, including cancer-associated fibroblasts, tumor endothelial cells, tumor-infiltrating immune cells, as well as the non-cellular TME components, such as extracellular matrix (ECM), metabolites, soluble factors (e.g., growth factors, cytokines and chemokines), and intra-tumoral microbiota. Together, OCT4 regulates crucial processes encompassing ECM remodeling, epithelial-mesenchymal transition, metabolic reprogramming, angiogenesis, and immune responses. The complex and bidirectional interactions between OCT4-expressing CSCs and the TME create a supportive niche for tumor growth, invasion, and resistance to therapy. Better understanding OCT4's roles in such interactions can provide deeper insights into potential therapeutic strategies and targets for disrupting the supportive environment of tumors. The emerging therapies targeting OCT4 in CSCs might hold promise to resensitize therapeutic-resistant cancer cells, and to eradicate all cancer cells when combined with other therapies targeting the bulk of differentiated cancer cells as well as the TME.

GDF15 inhibits early-stage adipocyte differentiation by enhancing HOP2 expression and suppressing C/EBPα expression

Excessive adipocyte differentiation and accumulation contribute to the development of metabolic disorders. Growth differentiation factor 15 (GDF15) plays an essential role in energy homeostasis and is considered an anti-obesity factor; however, elevated serum levels of endogenous GDF15 have been reported in certain individuals with obesity. In this study, to gain a better understanding of this complex relationship between GDF15 levels and obesity, we investigated GDF15 expression and function during adipogenesis. Compared with mice fed a normal diet, those fed a short-term high-fat diet exhibited a reduction in epididymal white adipose tissue and serum GDF15 expression. These results were confirmed in human adipose-derived stem cells that showed reduced GDF15 expression during adipogenesis differentiation. During adipogenesis, GDF15 was primarily degraded via the autophagy lysosomal pathway, and GDF15 overexpression in pre-adipocytes inhibited adipogenesis by suppressing CCAAT enhancer binding protein alpha (C/EBPα). Furthermore, whereas we detected a reduction in homologous-pairing protein 2 (HOP2) expression during adipogenesis, expression increased in response to an overexpression of GDF15. Furthermore, following knockdown of HOP2 during GDF15 overexpression, there was no suppression of C/EBPα expression. These findings indicate that GDF15 undergoes lysosomal degradation via an autophagic pathway and suppresses adipocyte differentiation via the HOP2-mediated inhibition of C/EBPα expression. Collectively, our findings indicate that GDF15 could serve as a potential therapeutic target for the treatment of metabolic disorders.

Myriad factors and pathways influencing tumor radiotherapy resistance

Radiotherapy is a cornerstone in the treatment of various tumors, yet radioresistance often leads to treatment failure and tumor recurrence. Several factors contribute to this resistance, including hypoxia, DNA repair mechanisms, and cancer stem cells. This review explores the diverse elements that drive tumor radiotherapy resistance. Historically, resistance has been attributed to cellular repair and tumor repopulation, but recent research has expanded this understanding. The tumor microenvironment - characterized by hypoxia, immune evasion, and stromal interactions - further complicates treatment. Additionally, molecular mechanisms such as aberrant signaling pathways, epigenetic modifications, and non-B-DNA structures play significant roles in mediating resistance. This review synthesizes current knowledge, highlighting the interplay of these factors and their clinical implications. Understanding these mechanisms is crucial for developing strategies to overcome resistance and improve therapeutic outcomes in cancer patients.

Dissecting the Impact of Genetic Background on Oncogenic Response to Radiation Exposure in the Ptch1+/- Mouse Model

Medulloblastoma (MB) is a common primary brain cancer in children. The sonic hedgehog (SHH) pathway is indispensable for the normal development of the cerebellum, and MB is often caused by persistent SHH activation owing to mutations in pathway components. Patched1 (PTCH1) is the primary receptor for the SHH ligand and a negative regulator of the SHH signal transduction pathway. Mice heterozygous for the Ptch1 gene (Ptch1+/-) are predisposed to MB development. Irradiation of newborn Ptch1+/- mice dramatically increases MB occurrence. A genetic background carrying the Ptch1 mutation significantly influences the risk of developing MB. This study aims to investigate the genetic background-related mechanisms that regulate radiation-induced cellular response and oncogenesis in the cerebellum. We employed multiple approaches, including: (a) analysis of cellular radiosensitivity in granule cell precursors (GCPs), the MB cells of origin, derived from Ptch1 mice with a genetic background that is sensitive (CD1) or resistant (C57Bl/6) to the induction of radiogenic MB; (b) identification of genes differentially expressed in spontaneous and radiation-induced MBs from these two mouse strains; (c) bioinformatic analysis to correlate the expression of radiation-induced genes with survival in MB patients; and (d) examining the expression of these genes in ex vivo MBs induced by single or repeated radiation doses. We have identified a potential gene expression signature-Trp53bp1, Bax, Cyclin D1, p21, and Nanog-that influences tumor response. In ex vivo cultured spontaneous MBs, the expression levels of these genes increase after irradiation in CD1 mice, but not in mice with a C57Bl/6 genetic background, suggesting that this signature could predict tumor response to radiation therapy and help develop strategies for targeting DNA damage repair in tumors. A detailed understanding of the mechanisms behind genetic background-related susceptibility to radiation-induced oncogenic responses is crucial for translational research.

Cancer stem cells: advances in knowledge and implications for cancer therapy

Cancer stem cells (CSCs), a small subset of cells in tumors that are characterized by self-renewal and continuous proliferation, lead to tumorigenesis, metastasis, and maintain tumor heterogeneity. Cancer continues to be a significant global disease burden. In the past, surgery, radiotherapy, and chemotherapy were the main cancer treatments. The technology of cancer treatments continues to develop and advance, and the emergence of targeted therapy, and immunotherapy provides more options for patients to a certain extent. However, the limitations of efficacy and treatment resistance are still inevitable. Our review begins with a brief introduction of the historical discoveries, original hypotheses, and pathways that regulate CSCs, such as WNT/β-Catenin, hedgehog, Notch, NF-κB, JAK/STAT, TGF-β, PI3K/AKT, PPAR pathway, and their crosstalk. We focus on the role of CSCs in various therapeutic outcomes and resistance, including how the treatments affect the content of CSCs and the alteration of related molecules, CSCs-mediated therapeutic resistance, and the clinical value of targeting CSCs in patients with refractory, progressed or advanced tumors. In summary, CSCs affect therapeutic efficacy, and the treatment method of targeting CSCs is still difficult to determine. Clarifying regulatory mechanisms and targeting biomarkers of CSCs is currently the mainstream idea.

Transcriptional regulation of cancer stem cell: regulatory factors elucidation and cancer treatment strategies

Cancer stem cells (CSCs) were first discovered in the 1990s, revealing the mysteries of cancer origin, migration, recurrence and drug-resistance from a new perspective. The expression of pluripotent genes and complex signal regulatory networks are significant features of CSC, also act as core factors to affect the characteristics of CSC. Transcription is a necessary link to regulate the phenotype and potential of CSC, involving chromatin environment, nucleosome occupancy, histone modification, transcription factor (TF) availability and cis-regulatory elements, which suffer from ambient pressure. Especially, the expression and activity of pluripotent TFs are deeply affected by both internal and external factors, which is the foundation of CSC transcriptional regulation in the current research framework. Growing evidence indicates that regulating epigenetic modifications to alter cancer stemness is effective, and some special promoters and enhancers can serve as targets to influence the properties of CSC. Clarifying the factors that regulate CSC transcription will assist us directly target key stem genes and TFs, or hinder CSC transcription through environmental and other related factors, in order to achieve the goal of inhibiting CSC and tumors. This paper comprehensively reviews the traditional aspects of transcriptional regulation, and explores the progress and insights of the impact on CSC transcription and status through tumor microenvironment (TME), hypoxia, metabolism and new meaningful regulatory factors in conjunction with the latest research. Finally, we present opinions on omnidirectional targeting CSCs transcription to eliminate CSCs and address tumor resistance.

Oct4 activates IL-17A to orchestrate M2 macrophage polarization and cervical cancer metastasis

BACKGROUND

Cervical cancer is a common malignant tumor in the female. Interleukin (IL)-17A is a proinflammatory factor and exerts a vital function in inflammatory diseases and cancers. M2 macrophage has been confirmed to promote tumor development. Nevertheless, it is not yet known whether IL-17A facilitates cervical cancer development by inducing M2 macrophage polarization. Therefore, this study was conducted to investigate the regulatory effect of IL-17A on M2 macrophage polarization and the underlying mechanism in cervical cancer development.

METHODS

RT-qPCR was utilized for testing IL-17A expression in cancer tissues and cells. Flow cytometry was applied to evaluate the M1 or M2 macrophage polarization. Cell proliferative, migratory, and invasive capabilities were measured through colony formation and transwell assays. ChIP and luciferase reporter assays were applied to determine the interaction between IL-17A and octamer-binding transcription factor 4 (OCT4).

RESULTS

IL-17A expression and concentration were high in metastatic tissues and cells of cervical cancer. IL-17A was found to facilitate M2 macrophage polarization in cervical cancer. Furthermore, IL-17A facilitated the macrophage-mediated promotion of cervical cancer cell proliferative, migratory, and invasive capabilities. Mechanistic assays manifested that Oct4 binds to and transcriptionally activated IL-17A in cervical cancer cells. Furthermore, Oct4 promoted cervical cancer cell malignant phenotype and M2 macrophage polarization by activating the p38 pathway that, in turn, upregulated IL-17A. Additionally, in vivo experiments confirmed that Oct4 knockdown reduced tumor growth and metastasis.

CONCLUSION

Oct4 triggers IL-17A to facilitate the polarization of M2 macrophages, which promotes cervical cancer cell metastasis.

SOX2 and OCT4 mediate radiation and drug resistance in pancreatic tumor organoids

Pancreatic cancer has a five-year survival rate of only 10%, mostly due to late diagnosis and limited treatment options. In patients with unresectable disease, either FOLFIRINOX, a combination of 5-fluorouracil (5-FU), oxaliplatin and irinotecan, or gemcitabine plus nab-paclitaxel combined with radiation are frontline standard regimens. However, chemo-radiation therapy has shown limited success because patients develop resistance to chemotherapy and/or radiation. In this study, we evaluated the role of pancreatic cancer stem cells (CSC) using OCT4 and SOX2, CSC markers in mouse pancreatic tumor organoids. We treated pancreatic tumor organoids with 4 or 8 Gy of radiation, 10 μM of 5-FU (5-Fluorouracil), and 100 μM 3-Bromopyruvate (3BP), a promising anti-cancer drug, as a single treatment modalities, and in combination with RT. Our results showed significant upregulation of, OCT4, and SOX2 expression in pancreatic tumor organoids treated with 4 and 8 Gy of radiation, and downregulation following 5-FU treatment. The expression of CSC markers with increasing treatment dose exhibited elevated upregulation levels to radiation and downregulation to 5-FU chemotherapy drug. Conversely, when tumor organoids were treated with a combination of 5-FU and radiation, there was a significant inhibition in SOX2 and OCT4 expression, indicating CSC self-renewal inhibition. Noticeably, we also observed that human pancreatic tumor tissues exhibited heterogeneous and aberrant OCT4 and SOX2 expression as compared to normal pancreas, indicating their potential role in pancreatic cancer growth and therapy resistance. In addition, the combination of 5-FU and radiation treatment exhibited significant inhibition of the β-catenin pathway in pancreatic tumor organoids, resulting in sensitization to treatment and organoid death. In conclusion, our study emphasizes the crucial role of CSCs in therapeutic resistance in PC treatment. We recommend using tumor organoids as a model system to explore the impact of CSCs in PC and identify new therapeutic targets.

RNA m5C modification upregulates E2F1 expression in a manner dependent on YBX1 phase separation and promotes tumor progression in ovarian cancer

5-Methylcytosine (m5C) is a common RNA modification that modulates gene expression at the posttranscriptional level, but the crosstalk between m5C RNA modification and biomolecule condensation, as well as transcription factor-mediated transcriptional regulation, in ovarian cancer, is poorly understood. In this study, we revealed that the RNA methyltransferase NSUN2 facilitates mRNA m5C modification and forms a positive feedback regulatory loop with the transcription factor E2F1 in ovarian cancer. Specifically, NSUN2 promotes m5C modification of E2F1 mRNA and increases its stability, and E2F1 binds to the NSUN2 promoter, subsequently reciprocally activating NSUN2 transcription. The RNA binding protein YBX1 functions as the m5C reader and is involved in NSUN2-mediated E2F1 regulation. m5C modification promotes YBX1 phase separation, which upregulates E2F1 expression. In ovarian cancer, NSUN2 and YBX1 are amplified and upregulated, and higher expression of NSUN2 and YBX1 predicts a worse prognosis for ovarian cancer patients. Moreover, E2F1 transcriptionally regulates the expression of the oncogenes MYBL2 and RAD54L, driving ovarian cancer progression. Thus, our study delineates a NSUN2-E2F1-NSUN2 loop regulated by m5C modification in a manner dependent on YBX1 phase separation, and this previously unidentified pathway could be a promising target for ovarian cancer treatment.

Small molecules that disrupt RAD54-BLM interaction hamper tumor proliferation in colon cancer chemoresistance models

RAD54 and BLM helicase play pivotal roles during homologous recombination repair (HRR) to ensure genome maintenance. BLM amino acids (aa 181-212) interact with RAD54 and enhance its chromatin remodeling activity. Functionally, this interaction heightens HRR, leading to a decrease in residual DNA damage in colon cancer cells. This contributes to chemoresistance in colon cancer cells against cisplatin, camptothecin, and oxaliplatin, eventually promoting tumorigenesis in preclinical colon cancer mouse models. ChIP-Seq analysis and validation revealed increased BLM and RAD54 corecruitment on the MRP2 promoter in camptothecin-resistant colon cancer cells, leading to BLM-dependent enhancement of RAD54-mediated chromatin remodeling. We screened the Prestwick small-molecule library, with the intent to revert camptothecin- and oxaliplatin-induced chemoresistance by disrupting the RAD54-BLM interaction. Three FDA/European Medicines Agency-approved candidates were identified that could disrupt this interaction. These drugs bound to RAD54, altered its conformation, and abrogated RAD54-BLM-dependent chromatin remodeling on G5E4 and MRP2 arrays. Notably, the small molecules also reduced HRR efficiency in resistant lines, diminished anchorage-independent growth, and hampered the proliferation of tumors generated using camptothecin- and oxaliplatin-resistant colon cancer cells in both xenograft and syngeneic mouse models in BLM-dependent manner. Therefore, the 3 identified small molecules can serve as possible viable candidates for adjunct therapy in colon cancer treatment.

Dauricine attenuates Oct4/sonic hedgehog co-activated stemness and induces reactive oxygen species-mediated mitochondrial apoptosis via AKT/β-catenin signaling in human neuroblastoma and glioblastoma stem-like cells

Neuroblastoma and glioblastoma are primary malignant tumors of the nervous system, with frequent relapse and limited clinical therapeutic drugs. The failure of their treatment is due to the tumor cells exhibiting cancer stem-like cells (CSLCs) properties. Octamer binding transcription factor 4 (Oct4) is involved in mediating CSLCs, our previous work found that Oct4-driven reprogramming of astrocytes into induced neural stem cells was potentiated with continuous sonic hedgehog (Shh) stimulation. In this study, we aimed to study the importance of Oct4 and Shh combination in the stemness properties induction of neuroblastoma and glioblastoma cells, and evaluate the anti-stemness effect of dauricine (DAU), a natural product of bis-benzylisoquinoline alkaloid. The effect of Oct4 and Shh co-activation on cancer stemness was evaluated by tumor spheres formation model and flow cytometry analysis. Then the effects of DAU on SH-SY5Y and T98-G cells were assessed by the MTT, colony formation, and tumor spheres formation model. DAU acts on Oct4 were verified using the Western blotting, MTT, and so on. Mechanistic studies were explored by siRNA transfection assay, Western blotting, and flow cytometry analysis. We identified that Shh effectively improved Oct4-mediated generation of stemness in SH-SY5Y and T98-G cells, and Oct4 and Shh co-activation promoted cell growth, the resistance of apoptosis. In addition, DAU, a natural product, was found to be able to attenuate Oct4/Shh co-activated stemness and induce cell cycle arrest and apoptosis via blocking AKT/β-catenin signaling in neuroblastoma and glioblastoma, which contributed to the neuroblastoma and glioblastoma cells growth inhibition by DAU. In summary, our results indicated that the treatment of DAU may be served as a potential therapeutic method in neuroblastoma and glioblastoma.

Recent Advances in the Targeting of Head and Neck Cancer Stem Cells

Head and neck squamous cell carcinoma (HNSCC) is a very heterogeneous cancer with a poor overall response to therapy. One of the reasons for this therapy resistance could be cancer stem cells (CSCs), a small population of cancer cells with self-renewal and tumor-initiating abilities. Tumor cell heterogeneity represents hurdles for therapeutic elimination of CSCs. Different signaling pathway activations, such as Wnt, Notch, and Sonic-Hedgehog (SHh) pathways, lead to the expression of several cancer stem factors that enable the maintenance of CSC features. Identification and isolation of CSCs are based either on markers (CD133, CD44, and aldehyde dehydrogenase (ALDH)), side populations, or their sphere-forming ability. A key challenge in cancer therapy targeting CSCs is overcoming chemotherapy and radiotherapy resistance. However, in novel therapies, various approaches are being employed to address this hurdle such as targeting cell surface markers, other stem cell markers, and different signaling or metabolic pathways, but also, introducing checkpoint inhibitors and natural compounds into the therapy can be beneficial.

Cancer stem cells of head and neck squamous cell carcinoma; distance towards clinical application; a systematic review of literature

Head and neck squamous cell carcinoma (HNSCC) is the major pathological type of head and neck cancer (HNC). The disease ranks sixth among the most common malignancies worldwide, with an increasing incidence rate yearly. Despite the development of therapy, the prognosis of HNSCC remains unsatisfactory, which may be attributed to the resistance to traditional radio-chemotherapy, relapse, and metastasis. To improve the diagnosis and treatment, the targeted therapy for HNSCC may be successful as that for some other tumors. Nanocarriers are the most effective system to deliver the anti-cancerous agent at the site of interest using passive or active targeting approaches. The system enhances the drug concentration in HCN target cells, increases retention, and reduces toxicity to normal cells. Among the different techniques in nanotechnology, quantum dots (QDs) possess multiple fluorescent colors emissions under single-source excitation and size-tunable light emission. Dendrimers are the most attractive nanocarriers, which possess the desired properties of drug retention, release, unaffecting by the immune system, blood circulation time enhancing, and cells or organs specific targeting properties. In this review, we have discussed the up-to-date knowledge of the Cancer Stem Cells of Head and Neck Squamous Cell Carcinoma. Although a lot of data is available, still much more efforts remain to be made to improve the treatment of HNSCC.

OCT4's role and mechanism underlying oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC), a common malignancy of the head and neck, ranks sixth worldwide in terms of cancers with the most negative impact, owing to tumor relapse rates, cervical lymphnode metastasis, and the lack of an efficacious systemic therapy. Its prognosis is poor, and its mortality rate is high. Octamer-binding transcription factor 4 (OCT4) is a member of the Pit-Oct-Unc (POU) family and is a key reprogramming factor that produces a marked effect in preserving the pluripotency and self-renewal state of embryonic stem cells (ESCs). According to recent studies, OCT4 participates in retaining the survival of OSCC cancer stem cells (CSCs), which has far-reaching implications for the occurrence, recurrence, metastasis, and prognosis of oral carcinogenesis. Therefore, we summarize the structure, subtypes, and function of OCT4 as well as its role in the occurrence, progression, and prognosis of OSCC.

Pan-Cancer Analysis of Oncogenic Role of RAD54L and Experimental Validation in Hepatocellular Carcinoma

Background

RAD54L is a prominent member of the SWI2/SNF2 protein family, primarily involved in the homologous recombination repair (HRR) process, thereby playing a pivotal role in the repair of DNA double-strand breaks (DSBs). RAD54L has been implicated in the development of numerous tumors. Consequently, we aimed to investigate the potential contribution of RAD54L in pan-cancer.

Methods

Various databases and analytical tools were employed for bioinformatics analysis. Moreover, in vitro experiments were conducted to corroborate the findings from the bioinformatics analysis and delve deeper into the role of RAD54L in hepatocellular carcinoma (HCC).

Results

RAD54L expression demonstrated a significant elevation in the majority of tumors, and its overexpression was strongly associated with unfavorable survival outcomes. RAD54L displayed robust correlations with the infiltration levels of various immune cells, including cancer associated fibroblasts (CAFs), endothelial cells, and myeloid-derived suppressor cells (MDSCs). Additionally, associations were observed between RAD54L and key factors such as tumor mutation burden (TMB), microsatellite instability (MSI), multiple immune checkpoints, and immune cell infiltration. Moreover, a close relationship was observed between RAD54L expression levels in HCC and clinicopathological characteristics, as well as immune cell infiltration. Experimental techniques including qRT-PCR, Western blotting, colony-forming, Cell Counting Kit-8 (CCK-8), wound-healing, and transwell assays were employed, which collectively demonstrated that RAD54L promoted the proliferation and migration of HCC cells.

Conclusion

RAD54L exhibits robust expression in both pan-cancer and HCC, exerting a significant influence on the proliferation and migration of HCC cells. These findings highlight its potential as a promising biomarker for pan-cancer and a prospective target for immunotherapy.

Mapping the Genetic Interaction Network of PARP inhibitor Response

Genetic interactions have long informed our understanding of the coordinated proteins and pathways that respond to DNA damage in mammalian cells, but systematic interrogation of the genetic network underlying that system has yet to be achieved. Towards this goal, we measured 147,153 pairwise interactions among genes implicated in PARP inhibitor (PARPi) response. Evaluating genetic interactions at this scale, with and without exposure to PARPi, revealed hierarchical organization of the pathways and complexes that maintain genome stability during normal growth and defined changes that occur upon accumulation of DNA lesions due to cytotoxic doses of PARPi. We uncovered unexpected relationships among DNA repair genes, including context-specific buffering interactions between the minimally characterized AUNIP and BRCA1-A complex genes. Our work thus establishes a foundation for mapping differential genetic interactions in mammalian cells and provides a comprehensive resource for future studies of DNA repair and PARP inhibitors.

Introducing novel key genes and transcription factors associated with rectal cancer response to chemoradiation through co-expression network analysis

Preoperative radiochemotherapy is a promising therapeutic method for locally advanced rectal cancer patients. However, the response of colorectal cancer (CRC) patients to preoperative radiotherapy varies widely. In this study, we aimed to identify novel biomarkers that could predict the response of colorectal tumors to treatment using a systems biology approach. We applied the Weighted Gene Co-Expression Network Analysis to construct co-expression networks and evaluated the correlation of these networks with radiation using the module-trait relationship. We then identified hub genes and related transcription factors in the selected co-expression module. Our analysis of seven constructed modules revealed that one module, which contained 113 nodes and 6066 edges, had the strongest correlation with radiation effects on CRC (correlation = 0.85; p-value = 6e-7). By analyzing the selected module with the CytoHubba plugin, we identified four hub genes, including ZEB2, JAM2, NDN, and PPAP2A. We also identified seven important transcription factors, including KLF4, SUZ12, TCF4, NANOG, POU5F1, SOX2, and SMARCA4, which may play essential roles in regulating the four hub genes. In summary, our findings suggest that ZEB2, JAM2, NDN, and PPAP2A, along with the seven transcription factors related to these hub genes, may be associated with the response of colorectal tumors to chemoradiotherapy.

Dihydroartemisinin inhibited stem cell-like properties and enhanced oxaliplatin sensitivity of colorectal cancer via AKT/mTOR signaling

Colorectal cancer (CRC) is a common tumor with high morbidity and mortality. The use of oxaliplatin (L-OHP) as a first-line treatment for CRC is limited due to chemoresistance. Growing evidence have revealed that the existence of cancer stem-like cells (CSLCs) is one of the important reasons for drug resistance and recurrence of cancers. Dihydroartemisinin (DHA), a derivative of artemisinin, has showed anticancer effects on a variety of malignancies, in addition to its antimalarial effects. However, the effect and mechanism of DHA on CSLCs and chemosensitivity in CRC cells remains unclear. In this study, we found that DHA inhibited cell viability in HCT116 and SW620 cells. Moreover, DHA decreased cell clonogenicity, and improved L-OHP sensitivity. Furthermore, DHA treatment attenuated tumor sphere formation, and the expressions of stem cell surface marker (CD133 and CD44) and stemness-associated transcription factor (Nanog, c-Myc, and OCT4). Mechanistically, the present findings showed that DHA inhibited of AKT/mTOR signaling pathway. The activation of AKT/mTOR signaling reversed DHA-decreased cell viability, clonogenicity, L-OHP resistance, tumor sphere, and expressions of stemness-associated protein in CRC. The inhibitory effect of DHA on tumorigenicity of CRC cells has also been demonstrated in BALB/c nude mice. In conclusion, this study revealed that DHA inhibited CSLCs properties in CRC via AKT/mTOR signaling, suggesting that DHA may be used as a potential therapeutic agent for CRC.

Immunotargeting of Cancer Stem Cells

The generally accepted view is that CSCs hijack the signaling pathways attributed to normal stem cells that regulate the self-renewal and differentiation processes. Therefore, the development of selective targeting strategies for CSC, although clinically meaningful, is associated with significant challenges because CSC and normal stem cells share many important signaling mechanisms for their maintenance and survival. Furthermore, the efficacy of this therapy is opposed by tumor heterogeneity and CSC plasticity. While there have been considerable efforts to target CSC populations by the chemical inhibition of the developmental pathways such as Notch, Hedgehog (Hh), and Wnt/β-catenin, noticeably fewer attempts were focused on the stimulation of the immune response by CSC-specific antigens, including cell-surface targets. Cancer immunotherapies are based on triggering the anti-tumor immune response by specific activation and targeted redirecting of immune cells toward tumor cells. This review is focused on CSC-directed immunotherapeutic approaches such as bispecific antibodies and antibody-drug candidates, CSC-targeted cellular immunotherapies, and immune-based vaccines. We discuss the strategies to improve the safety and efficacy of the different immunotherapeutic approaches and describe the current state of their clinical development.

Cancer stem cells (CSCs): key player of radiotherapy resistance and its clinical significance

Cancer stem cells (CSCs) are self-renewing and slow-multiplying micro subpopulations in tumour microenvironments. CSCs contribute to cancer's resistance to radiation (including radiation) and other treatments. CSCs control the heterogeneity of the tumour. It alters the tumour's microenvironment cellular singling and promotes epithelial-to-mesenchymal transition (EMT). Current research decodes the role of extracellular vesicles (EVs) and CSCs interlink in radiation resistance. Exosome is a subpopulation of EVs and originated from plasma membrane. It is secreted by several active cells. It involed in cellular communication and messenger of healthly and multiple pathological complications. Exosomal biological active cargos (DNA, RNA, protein, lipid and glycan), are capable to transform recipient cells' nature. The molecular signatures of CSCs and CSC-derived exosomes are potential source of cancer theranostics development. This review discusse cancer stem cells, radiation-mediated CSCs development, EMT associated with CSCs, the role of exosomes in radioresistance development, the current state of radiation therapy and the use of CSCs and CSCs-derived exosomes biomolecules as a clinical screening biomarker for cancer. This review gives new researchers a reason to keep an eye on the next phase of scientific research into cancer theranostics that will help mankind.

Identity matters: cancer stem cells and tumour plasticity in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) represents frequent yet aggressive tumours that encompass complex ecosystems of stromal and neoplastic components including a dynamic population of cancer stem cells (CSCs). Recently, research in the field of CSCs has gained increased momentum owing in part to their role in tumourigenicity, metastasis, therapy resistance and relapse. We provide herein a comprehensive assessment of the latest progress in comprehending CSC plasticity, including newly discovered influencing factors and their possible application in HNSCC. We further discuss the dynamic interplay of CSCs within tumour microenvironment considering our evolving appreciation of the contribution of oral microbiota and the pressing need for relevant models depicting their features. In sum, CSCs and tumour plasticity represent an exciting and expanding battleground with great implications for cancer therapy that are only beginning to be appreciated in head and neck oncology.

CD24+CD44+CD54+EpCAM+ gastric cancer stem cells predict tumor progression and metastasis: clinical and experimental evidence

BACKGROUND

Gastric cancer (GC) is a leading cause of cancer-related deaths worldwide. Specific and thorough identification of cancer cell subsets with higher tumorigenicity and chemoresistance, such as cancer stem cells (CSCs), could lead to the development of new and promising therapeutic targets. For better CSC identification, a complete or extended surface marker phenotype is needed to provide increased specificity for new cell targeting approaches. Our goal is to identify and characterize a putative extended phenotype for CSCs derived from patients with GC before treatment, as well as to evaluate its clinical value. In addition, we aim to ensure that cells with this phenotype have stemness and self-renewal capabilities.

METHODS

This is a cohort study including 127 treatment-naïve patients with GC who attended the Instituto Nacional de Cancerología. Multiparametric flow cytometry analysis was performed to determine the extended phenotype of cells derived from gastric biopsies. The tumorigenic capability of cells identified in patients was assessed in a zebrafish model.

RESULTS

CD24+CD44+CD54+EpCAM+ cells were present in all treatment-naïve patients included, with a median abundance of 1.16% (0.57-1.89%). The percentage of CD24+CD44+CD54+EpCAM+ cells was categorized as high or low using 1.19% as the cutoff for the CD24+CD44+CD54+EpCAM+ cell subset. Additionally, a higher TNM stage correlated with a higher percentage of CD24+CD44+CD54+EpCAM+ cells (Rho coefficient 0.369; p < 0.0001). We also demonstrated that a higher percentage of CD24+CD44+CD54+EpCAM+ cells was positively associated with metastasis. The metastatic potential of these cells was confirmed in a zebrafish model. Ultimately, under our conditions, we conclude that CD24+CD44+CD54+EpCAM+ cells are true gastric cancer stem cells (GCSCs).

CONCLUSION

The CD24+CD44+CD54+EpCAM+ cells present in tissue samples from patients are true GCSCs. This extended phenotype results in better and more specific characterization of these highly tumorigenic cells. The relative quantification of CD24+CD44+CD54+EpCAM+ cells has potential clinical value, as these cells are associated with metastatic disease, making their presence an additional prognostic marker and possibly a target for the design of new antineoplastic treatments in the era of precision oncology. Overall, the extended CD24+CD44+CD54+EpCAM+ phenotype of GCSCs could support their isolation for the study of their stemness mechanisms, leading to the identification of better molecular targets for the development of both new therapeutic approaches such as oncoimmunotherapy and new diagnostic and clinical prognostic strategies for GC.

Oct4 promoted proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in colon cancer cells by activating the SCF/c-Kit signaling pathway

Octamer-binding transcription factor 4 (Oct4) is closely related to the occurrence and development of cancer. In the present study, we paid a special interest in exploring the effect of Oct4 on colon cancer (CC) proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) and its molecular mechanism. Immunohistochemistry (IHC) was used to detect the expression level of Oct4 in colon tissue of patients with colon cancer. Oct4 overexpression vector pcDNA-Oct4 was used to stably express Oct4 in human colon cancer cells HT29 and SW480. Cell counting kit-8 (CCK-8) assay was used to detect the cell proliferation. The invasion and migration abilities were observed by transwell and wound healing assays. The expression of EMT relate genes were observed by Western blot. We found that Oct4 was up-regulated in human colon cancer tissues than that in paracancerous tissues. The proliferation, migration, and invasion of HT29 and SW480 cells was significantly induced by transfection of pcDNA-Oct4. Furthermore, Oct4 overexpression enhanced EMT of CC cells, characterized by the increased expression of vimentin, Twist, and Snail, as well as decreased expression of E-cadherin. Mechanistically, Oct4 overexpression activated stem cell factor (SCF)/c-Kit signaling pathway in CC cells, and the SCF/c-Kit signaling inhibitor imatinib reversed pro-oncogenic effects of Oct4. These finding provide an insight into the potential of Oct4 for CC diagnosis and therapy.

A positive feedback loop: RAD18-YAP-TGF-β between triple-negative breast cancer and macrophages regulates cancer stemness and progression

As a key regulator of the DNA translesion synthesis (TLS) pathway, RAD18 is error-prone and contributes to the accumulation of DNA mutations. Our previous study showed that it plays an essential role in the progression of multiple tumors. However, the mechanism through which RAD18 influences triple-negative breast cancer (TNBC), especially the interaction between tumor cells and the tumor microenvironment, remains elusive. In this study, we showed that RAD18 expression is markedly higher in patients with high T stage TNBC and inversely correlated with prognosis. High expression of RAD18 facilitated a highly stem-cell phenotype through the Hippo/YAP pathway, which supports the proliferation of TNBC. In addition, the cytokine byproduct TGF-β activates macrophages to have an M2-like tumor-associated macrophage (TAM) phenotype. Reciprocally, TGF-β from TAMs activated RAD18 in TNBC to enhance tumor stemness, forming a positive feedback loop. Inhibition of YAP or TGF-β breaks this loop and suppresses cancer stemness and proliferation In nude mice, RAD18 promoted subcutaneous transplanted tumor growth and M2-type TAM recruitment. Collectively, the RAD18-YAP-TGF-β loop is essential for the promotion of the stemness phenotype by TNBC and could be a potential therapeutic target for TNBC.

Cancer Stem Cell DNA Enabled Real-Time Genotyping with Self-Functionalized Quantum Superstructures-Overcoming the Barriers of Noninvasive cfDNA Cancer Diagnostics

Cancer diagnosis and determining its tissue of origin are crucial for clinical implementation of personalized medicine. Conventional diagnostic techniques such as imaging and tissue biopsy are unable to capture the dynamic tumor landscape. Although circulating tumor DNA (ctDNA) shows promise for diagnosis, the clinical relevance of ctDNA remains largely undetermined due to several biological and technical complexities. Here, cancer stem cell-ctDNA is used to overcome the biological complexities like the inability for molecular analysis of ctDNA and dependence on ctDNA concentration rather than the molecular profile. Ultrasensitive quantum superstructures overcome the technical complexities of trace-level detection and rapid diagnosis to detect ctDNA within its short half-life. Activation of multiple surface enhanced Raman scattering mechanisms of the quantum superstructures achieved a very high enhancement factor (1.35 × 10¹¹ ) and detection at ultralow concentration (10^-15 M) with very high reliability (RSD: 3-12%). Pilot validation with clinical plasma samples from an independent validation cohort achieved a diagnosis sensitivity of ≈95% and specificity of 83%. Quantum superstructures identified the tissue of origin with ≈75-86% sensitivity and ≈92-96% specificity. With large scale clinical validation, the technology can develop into a clinically useful liquid biopsy tool improving cancer diagnostics.

Cisplatin overcomes radiotherapy resistance in OCT4-expressing head and neck squamous cell carcinoma

OBJECTIVES

Cisplatin is combined with radiotherapy for advanced head and neck squamous cell carcinoma (HNSCC). While providing a beneficial effect on survival, it also causes side effects and thus is an important target when considering treatment de-escalation. Currently, there are no biomarkers to predict its patient-selective therapeutic utility. In this study, we examined the role of the stem cell factor OCT4 as a potential biomarker to help clinicians stratify HNSCC patients between radiotherapy and chemoradiotherapy.

MATERIALS AND METHODS

OCT4 immunohistochemical staining of a population-validated tissue microarray (PV-TMA) (n = 166) representative of a standard HNSCC patients was carried out, and 5-year survival was analyzed. The results were validated using ex vivo drug sensitivity analysis of HNSCC tumor samples, and further cross-validated in independent oropharyngeal (n = 118), nasopharyngeal (n = 170), and vulvar carcinoma (n = 95) clinical datasets. In vitro, genetically modified, patient-derived HNSCC cells were used.

RESULTS

OCT4 expression in HNSCC tumors was associated with radioresistance. However, combination therapy with cisplatin was found to overcome thisradioresistance in OCT4-expressing HNSCC tumors. The results were validated by using several independent patient cohorts. Furthermore, CRISPRa-based OCT4 overexpression in the HNSCC cell line resulted in apoptosis resistance, and cisplatin was found to downregulate OCT4 protein expression in vitro. Ex vivo drug sensitivity analysis of HNSCC tumors confirmed the association between OCT4 expression and cisplatin sensitivity.

CONCLUSION

This study introduces OCT4 immunohistochemistry as a simple and cost-effective diagnostic approach for clinical practice to identify HNSCC patients benefitting from radiosensitization by cisplatin using either full or reduced dosing.

San-Zhong-Kui-Jian-Tang Exerts Antitumor Effects Associated With Decreased Cell Proliferation and Metastasis by Targeting ERK and the Epithelial-Mesenchymal Transition Pathway in Oral Cavity Squamous Cell Carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is an aggressive cancer whose 5-year survival rate remains poor. San-Zhong-Kui-Jian-Tang (SZKJT), a Chinese herbal formula, has long been used in clinical practice as adjuvant therapy in cancers. However, its therapeutic effects and molecular mechanisms in OSCC remain unclear.

METHODS

We investigated the potential therapeutic effects and molecular mechanism of SZKJT in OSCC in tumor cell lines and in tumor xenograft mice and evaluated combined SZKJT and cisplatin treatment efficacy. In vitro-cultured OSCC cells were administered SZKJT at different doses or SZKJT plus cisplatin, and cell proliferation, colony formation assays, and cell cycle analysis were used to assess the effects on cancer cell proliferation and apoptosis. We also analyzed the effects of SZKJT on oral cancer cell line migration, the regulation of mitogen-activated protein kinase (MAPK) signaling, and epithelial-mesenchymal transition (EMT)-associated genes. The antitumor effects of SZKJT plus cisplatin were also tested in vivo using a tumor-bearing NOD/SCID mice model.

RESULTS

The results showed that SZKJT effectively inhibited OSCC cell proliferation, induced cell cycle S phase arrest, and induced cell apoptosis. SZKJT also inhibited cell migration by modulating the MAPK signaling and epithelial-mesenchymal transition (EMT) pathway. Further exploration suggested that SZKJT affects OSCC by modulating ERK pathway; downregulating vimentin, fibronectin, and Oct-4; and upregulating E-cadherin. In vivo, SZKJT significantly inhibited tumor growth, and SZKJT and cisplatin exerted synergistic antitumor effects in model animals.

CONCLUSIONS

SZKJT exerts antitumor effects in OSCC cells. Additionally, SZKJT and cisplatin exhibit synergy in OSCC treatment. These findings support the clinical usage of Chinese herbal formulas as adjuvant therapy with chemotherapy in cancer treatment.

Two novel biallelic mutations in PSMC3IP in a patient affected by premature ovarian insufficiency

Premature ovarian insufficiency (POI) is a heterogeneous condition occurring when a woman experiences a loss of ovarian activity before the age of 40. POI is one of the most common reproductive endocrine diseases in women of childbearing age. The present study investigated the clinical manifestations and genetic features of a Chinese patient affected by POI. Next‑generation whole‑exome capture sequencing with Sanger direct sequencing were applied to the proband and her clinically unaffected family members. Two novel compound heterozygous mutations were identified in PSMC3IP. The first was a splicing mutation (c.597+1G>T) that was inherited from her father, whereas the second mutation (c.268G>C p.D90H) was discovered in both her mother and younger sister. The two mutations were co‑segregated with the disease phenotype in the family. In conclusion, the findings of the present study further support the key role of PSMC3IP in the etiology of POI and provide a novel insight into elucidating the mechanisms of female infertility.

The multiple faces of NANOG in cancer: a therapeutic target to chemosensitize therapy-resistant cancers

The transcription factor NANOG regulates self-renewal and pluripotency in embryonic cells, and its downregulation leads to cell differentiation. Recent studies have linked upregulation of NANOG in various cancers and the regulation of expression of different molecules, and vice versa, to induce proliferation, metastasis, invasion and chemoresistance. Thus NANOG is an oncogene that functions by inducing stem cells' circuitries and heterogeneity in cancers. Understanding NANOG's role in various cancers may lead to it becoming a therapeutic target to halt cancer progression. The NANOG network can also be targeted to resensitize resistant cancer cells to conventional therapies. The current review focuses on NANOG regulation in the various signaling networks leading to cancer progression and chemoresistance, and highlights the therapeutic aspect of targeting NANOG in various cancers.

In Search of a Unifying Concept in Human Diseases

Throughout the history of biological/medicine sciences, there has been opposing strategies to find solutions to complex human disease problems. Both empirical and deductive approaches have led to major insights and concepts that have led to practical preventive and therapeutic benefits for the human population. The classic definitions of "science" (to know) has been paired with the classic definition of technology (to do). One knew more as the technology developed, and that development was often based on science. In other words, one could do more if science could improve the technology. In turn, this made possible to know more science with improved technology. However, with the development of new technologies of today in biology and medicine, major advances have been made, such as the information from the Human Genome Project, genetic engineering techniques and the use of bioinformatic uses of sophisticated computer analyses. This has led to the renewed idea that Precision Medicine, while raising some serious ethical concerns, also raises the expectation of improved potential of risk predictions for prevention and treatment of various genetically and environmentally influenced human diseases. This new field Artificial Intelligence, as a major handmaiden to Precision Medicine, is significantly altering the fundamental means of biological discovery. However, can today's fundamental premise of "Artificial Intelligence", based on identifying DNA, as the primary nexus of human health and disease, provide the practical solutions to complex human diseases that involve the interaction of those genes with the broad spectrum of "environmental factors"? Will it be "precise" enough to provide practical solutions for prevention and treatments of diseases? In this "Commentary", with the example of human carcinogenesis, it will be challenged that, without the integration of mechanistic and hypothesis-driven approaches with the "unbiased" empirical analyses of large numbers of data, the Artificial Intelligence approach with fall short.

Beyond the Double-Strand Breaks: The Role of DNA Repair Proteins in Cancer Stem-Cell Regulation

Simple Summary

Cancer stem cells (CSCs) are a tumor cell population maintaining tumor growth and promoting tumor relapse if not wholly eradicated during treatment. CSCs are often equipped with molecular mechanisms making them resistant to conventional anti-cancer therapies whose curative potential depends on DNA damage-induced cell death. An elevated expression of some key DNA repair proteins is one of such defense mechanisms. However, new research reveals that the role of critical DNA repair proteins is extending far beyond the DNA repair mechanisms. This review discusses the diverse biological functions of DNA repair proteins in CSC maintenance and the adaptation to replication and oxidative stress, anti-cancer immune response, epigenetic reprogramming, and intracellular signaling mechanisms. It also provides an overview of their potential therapeutic targeting.

Abstract

Cancer stem cells (CSCs) are pluripotent and highly tumorigenic cells that can re-populate a tumor and cause relapses even after initially successful therapy. As with tissue stem cells, CSCs possess enhanced DNA repair mechanisms. An active DNA damage response alleviates the increased oxidative and replicative stress and leads to therapy resistance. On the other hand, mutations in DNA repair genes cause genomic instability, therefore driving tumor evolution and developing highly aggressive CSC phenotypes. However, the role of DNA repair proteins in CSCs extends beyond the level of DNA damage. In recent years, more and more studies have reported the unexpected role of DNA repair proteins in the regulation of transcription, CSC signaling pathways, intracellular levels of reactive oxygen species (ROS), and epithelial–mesenchymal transition (EMT). Moreover, DNA damage signaling plays an essential role in the immune response towards tumor cells. Due to its high importance for the CSC phenotype and treatment resistance, the DNA damage response is a promising target for individualized therapies. Furthermore, understanding the dependence of CSC on DNA repair pathways can be therapeutically exploited to induce synthetic lethality and sensitize CSCs to anti-cancer therapies. This review discusses the different roles of DNA repair proteins in CSC maintenance and their potential as therapeutic targets.

On the potential origin and characteristics of cancer stem cells

The 'cancer stem cell' hypothesis has pointed to a specific target for new cancer therapies. The hypothesis is based on the observation that only the 'cancer stem cell' among the other heterogeneous cancer cells can sustain the growth of the cancer. The goal is to identify biomarkers of 'cancer stem cells' to distinguish them from the 'cancer non-stem cells' and normal adult tissue-specific stem cells. This analyst posits a hypothesis that, although all cancers originated from a single cell, there exist two types of 'cancer stem cells' either by the 'Stem Cell hypothesis' or from the 'De-differentiation hypothesis'. It is proposed that there exist two different 'cancer stem cells'. Some 'cancer stem cells' (a) lack the expression of connexins or gap junction genes and lack any form of gap junctional intercellular communication (GJIC) or (b) they have the expressed connexin-coded proteins for functional GJIC but are dysfunctional by some expressed oncogene. This is consistent with the Loewenstein hypothesis that a universal characteristic of cancer cells is they do not have growth control, nor terminally differentiate. This review speculates the normal organ-specific adult stem cell, that is 'initiated', is the origin of the 'cancer stem cells' with expressed Oct4A gene and no expressed connexin genes; whereas the other cancer stem cell has no expressed Oct4A genes but expressed connexin gene, whose coded protein is dysfunctional. Hence. both types of 'cancer stem cells' lack GJIC, for two different reasons, the selective therapies have to be different for these different cell types.