Embryonic stem cell-specific signature in cervical cancer

HnRNP K regulates inflammatory gene expression by mediating splicing pattern of transcriptional factors

HnRNP K is a heterogeneous nuclear ribonucleoprotein and has been identified as an oncogene in most solid tumors via regulating gene expression or alternative splicing of genes by binding both DNA and pre-mRNA. However, how hnRNP K affects tumorigenesis and regulates the gene expression in cervical cancer (CESC) remains to be elucidated. In these data, higher expression of hnRNP K was observed in CESC and was negatively correlated with the patient survival time. We then overexpressed hnRNP K (hnRNP K-OE) and found that its overexpression promoted cell proliferation in HeLa cells (P = 0.0052). Next, global transcriptome sequencing (RNA-seq) experiments were conducted to explore gene expression and alternative splicing profiles regulated by hnRNP K. It is shown that upregulated genes by hnRNP K-OE were associated with inflammatory response and an apoptotic process of neuron cells, which involves in cancer. In addition, the alternative splicing of those genes regulated by hnRNP K-OE was associated with transcriptional regulation. Analysis of the binding features of dysregulated transcription factors (TFs) in the promoter region of the inflammatory response genes regulated by hnRNP K revealed that hnRNP K may modulate the expression level of genes related to inflammatory response by influencing the alternative splicing of TFs. Among these hnRNP K-TFs-inflammatory gene regulatory networks, quantitative reverse transcription polymerase chain reaction (RT-qPCR) experiments and gene silencing were conducted to verify the hnRNP K-IRF1-CCL5 axis. In conclusion, the hnRNP K-TFs-inflammatory gene regulatory axis provides a novel molecular mechanism for hnRNP K in promoting CESC and offers a new therapeutic target.

Infection by High-Risk Human Papillomaviruses, Epithelial-to-Mesenchymal Transition and Squamous Pre-Malignant or Malignant Lesions of the Uterine Cervix: A Series of Chained Events?

Wound healing requires static epithelial cells to gradually assume a mobile phenotype through a multi-step process termed epithelial-to-mesenchymal transition (EMT). Although it is inherently transient and reversible, EMT perdures and is abnormally activated when the epithelium is chronically exposed to pathogens: this event deeply alters the tissue and eventually contributes to the development of diseases. Among the many of them is uterine cervical squamous cell carcinoma (SCC), the most frequent malignancy of the female genital system. SCC, whose onset is associated with the persistent infection of the uterine cervix by high-risk human papillomaviruses (HR-HPVs), often relapses and/or metastasizes, being resistant to conventional chemo- or radiotherapy. Given that these fearsome clinical features may stem, at least in part, from the exacerbated and long-lasting EMT occurring in the HPV-infected cervix; here we have reviewed published studies concerning the impact that HPV oncoproteins, cellular tumor suppressors, regulators of gene expression, inflammatory cytokines or growth factors, and the interactions among these effectors have on EMT induction and cervical carcinogenesis. It is predictable and desirable that a broader comprehension of the role that EMT inducers play in SCC pathogenesis will provide indications to flourish new strategies directed against this aggressive tumor.

An Insight into the Role of UTF1 in Development, Stem Cells, and Cancer

The curiosity to understand the mechanisms regulating transcription in pluripotent cells resulted in identifying a unique transcription factor named Undifferentiated embryonic cell transcription factor 1 (UTF1). This proline-rich, nuclear protein is highly conserved among placental mammals with prominent expression observed in pluripotent, germ, and cancer cells. In pluripotent and germ cells, its role has been implicated primarily in proper cell differentiation, whereas in cancer, it shows tissue-specific function, either as an oncogene or a tumor suppressor gene. Furthermore, UTF1 is crucial for germ cell development, spermatogenesis, and maintaining male fertility in mice. In addition, recent studies have demonstrated the importance of UTF1 in the generation of high quality induced Pluripotent Stem Cells (iPSCs) and as an excellent biomarker to identify bona fide iPSCs. Functionally, UTF1 aids in establishing a favorable chromatin state in embryonic stem cells, reducing "transcriptional noise" and possibly functions similarly in re-establishing this state in differentiated cells upon their reprogramming to generate mature iPSCs. This review highlights the multifaceted roles of UTF1 and its implication in development, spermatogenesis, stem, and cancer cells.

CD109 mediates tumorigenicity and cancer aggressiveness via regulation of EGFR and STAT3 signalling in cervical squamous cell carcinoma

Background

CD109 was involved in the tumorigenesis and progression of various cancers via TGF-β1 signalling and STAT3 activation. As CD109 is strongly expressed in cervical squamous cell carcinoma, this study was conducted to investigate its functional characteristics in cervical cancer.

Methods

CD109 expression was examined by immunohistochemistry (IHC) with cervical tissue microarray. The effects of CD109 expression were examined on migration, cell proliferation, spheroid formation and soft-agar colony-formation assay. Meanwhile, cervical cancer cell lines with high CD109 expression were chosen for the functional study using siRNA knockdown and CRISPR/Cas9 knockout.

Results

IHC demonstrated an upregulation of CD109 in the cell membrane of cervical squamous cell carcinoma. CD109( + ) cells isolated by flow-cytometric sorting displayed enhanced migration, cell proliferation, sphere-forming and anchorage-independent cell growth ability. In contrast, silencing of CD109 expression could reverse the in vitro and in vivo tumorigenic and aggressive properties. Furthermore, CD109 induced EGFR-mediated STAT3 phosphorylation known to be responsible for cell migration, proliferation and maintenance of CSC phenotype.

Conclusion

Abundant CD109( + ) populations in cervical cancer cells potentially contributed to carcinogenesis and aggressiveness, whereas silencing of CD109 expression could reverse those properties. CD109 mediates cervical tumorigenicity and aggressiveness via CD109/EGFR/STAT3 signalling.

Role of Oct3/4 in Cervical Cancer Tumorigenesis

Cervical cancer (CC) is the fourth most common type of cancer that affects women. Compared to other types of cancer, CC has a high mortality rate in women worldwide. Several factors contribute to the development of CC, but persistent high-risk human papillomavirus infection is the main etiologic agent associated with the development of CC. Moreover, several studies reported that alterations in the expression of transcription factors present in a small subpopulation of cells within tumors called cancer stem cells (CSCs), which contribute to the development of CC by promoting tumorigenicity and metastasis. These transcription factors affect self-renewal and maintenance of pluripotency and differentiation in stem cells. OCT3/4 belongs to the family of transcription factors with the POU domain. It consists of five exons and can be edited by alternative splicing into three main transcripts: OCT3/4A, OCT3/4B, and OCT3/4B1. The OCT3/4 expression in CSCs promotes carcinogenesis and the development of malignant tumors, and the loss of expression leads to the loss of self-renewal and proliferation and favors apoptosis. This review describes the main roles of OCT3/4 in CC and its importance in several biological processes that contribute to the development of CC and may serve as molecular targets to improve prognosis of CC.

TRA-1-60-positive/CD45low cells found in the peripheral blood of prostate cancer patients with metastatic disease - A proof-of-concept study

Purpose

Over 90% of all cancer related deaths are due to metastasis. However, current diagnostic tools can't reliably discriminate between invasive and localized cancers.

Patients and methods

In this proof-of-concept study, we employed the embryonic stem cell marker TRA-1-60 (TRA+) to identify TRA + cells within the blood of prostate cancer patients and searched for TRA + cells in men with metastatic and localized cancers. We isolated whole peripheral blood mononuclear cells from 26 metastatic prostate cancer patients, from 13 patients with localized prostate cancer and from 17 healthy controls. Cells were stained for DAPI, CD45 and TRA + by immunofluorescence and imaged by epi-fluorescence microscopy. Imaged-based software was used both to identify TRA + cells, and to analyze CD45 levels in TRA+ and negative cells.

Results

We found high numbers of TRA + cells within the blood of metastatic cancer patients, whereas healthy individuals or men with localized prostate cancer showed none or very low numbers of TRA + cells. Further analysis of the CD45 levels of TRA + cells revealed a small population of TRA + cells with almost undetectable CD45 levels that were found frequently in metastatic prostate cancer patients. By excluding CD45 positive cells from the TRA + cell pool, we were able to refine the assay to be highly specific in identifying men with metastatic disease. In fact, the difference of CD45 levels between TRA+ and negative cells was a robust measure to distinguish between men with localized and metastatic prostate cancers in this small patient cohort.

Conclusions

The data suggest that metastatic prostate cancer patient have significant numbers of TRA+/CD45^low cells which might represent a potential tool for diagnostic assessment in the future.

CRKL regulates alternative splicing of cancer-related genes in cervical cancer samples and HeLa cell

BACKGROUND

Aberrant spliced isoforms are specifically associated with cancer progression and metastasis. The cytoplasmic adaptor CRKL (v-crk avian sarcoma virus CT10 oncogene homolog-like) is a CRK like proto-oncogene, which encodes a SH2 and SH3 (src homology) domain-containing adaptor protein. CRKL is tightly linked to leukemia via its binding partners BCR-ABL and TEL-ABL, upregulated in multiple types of human cancers, and induce cancer cell proliferation and invasion. However, it remains unclear whether signaling adaptors such as CRKL could regulate alternative splicing.

METHODS

We analyzed the expression level of CRKL in 305 cervical cancer tissue samples available in TCGA database, and then selected two groups of cancer samples with CRKL differentially expressed to analyzed potential CRKL-regulated alternative splicing events (ASEs). CRKL was knocked down by shRNA to further study CRKL-regulated alternative splicing and the activity of SR protein kinases in HeLa cells using RNA-Seq and Western blot techniques. We validated 43 CRKL-regulated ASEs detected by RNA-seq in HeLa cells, using RT-qPCR analysis of HeLa cell samples and using RNA-seq data of the two group of clinical cervical samples.

RESULTS

The expression of CRKL was mostly up-regulated in stage I cervical cancer samples. Knock-down of CRKL led to a reduced cell proliferation. CRKL-regulated alternative splicing of a large number of genes were enriched in cancer-related functional pathways, among which DNA repair and G2/M mitotic cell cycle, GnRH signaling were shared among the top 10 enriched GO terms and KEGG pathways by results from clinical samples and HeLa cell model. We showed that CRKL-regulated ASEs revealed by computational analysis using ABLas software in HeLa cell were highly validated by RT-qPCR, and also validated by cervical cancer clinical samples.

CONCLUSIONS

This is the first report of CRKL-regulation of the alternative splicing of a number of genes critical in tumorigenesis and cancer progression, which is consistent with CRKL reported role as a signaling adaptor and a kinase. Our results underline that the signaling adaptor CRKL might integrate the external and intrinsic cellular signals and coordinate the dynamic activation of cellular signaling pathways including alternative splicing regulation.

Potential role of cancer stem cells as biomarkers and therapeutic targets in cervical cancer

BACKGROUND

Eradicating cancer stem cells (CSCs) that are termed as the "beating heart" of various malignant tumors, including cervical cancer, holds great importance in cancer therapeutics. CSCs not only confer chemo-radio resistance but also play an important role in tumor metastasis and thereby pose a potential barrier for the cure of cervical cancer. Cervical cancer, a common malignancy among females, is associated with high morbidity and mortality rates, and the study on CSCs residing in the niche is promising.

RECENT FINDINGS

Biomarker approach to screen the cervical CSCs has gained impetus since the past decade. Progress in identification and characterization of the stem cell biomarkers has led to many insights. For the diagnostic purpose, several biomarkers like viral (HPV16), stem cell markers, transcription factors (viz, SOX2, OCT 4, and c-Myc), and CSC surface markers (viz, ALDH1 and CD44) have been identified. The research so far has been directed to study the CSC stemness and demonstrates various gene expression signatures in cervical CSCs. Such studies hold a potential to improve diagnostic accuracy and predict therapeutic response and clinical outcome in patients.

CONCLUSIONS

Stem cell biomarkers have been validated and their therapeutic targets are being developed as "strategies to improve therapeutic ratio in personalized medicine." This review gives a brief overview of the cervical CSC biomarkers, their current and future diagnostic, prognostic, and therapeutic potential.

MiR-148a suppressed cell invasion and migration via targeting WNT10b and modulating β-catenin signaling in cisplatin-resistant colorectal cancer cells

Cancer stem cells (CSCs) are suggested to be responsible for high recurrence rate and metastasis of colorectal cancer (CRC). Identifying novel targets that can suppress CSCs proliferation and metastasis may provide novel approach to combat against CRC. In the present study, we examined the role of miR-148a in cisplatin-resistant CRC cells with enhanced stem cell marker expression and explored the underlying mechanisms. In this study, we used cisplatin to selectively enrich cisplatin-resistant CRC cells from SW480 cell line, and these selected cisplatin-resistant SW480 cells were with significantly enhanced expression of stem cell markers and increased chemoresistance. MicroRNA (miRNA) array and qRT-PCR assay identified the down-regulation of miR-148a in cisplatin-resistant SW480 cells. Overexpression of miR-148a suppressed expression of stem cell markers, inhibited sphere formation, invasion and migration, induced apoptosis, and reduced chemo-resistance in cisplatin-resistant SW480 cells. Bioinformatics prediction and luciferase reporter assay revealed that WNT10b was a downstream target of miR-148a, and overexpression of miR-148a suppressed WNT10b expression and β-catenin signaling activities. Enforced expression WNT10b attenuated the effects of miR-148a on cisplatin-resistant SW480 cells sphere formation, invasion and migration. Further study showed that overexpression of miR-148a also suppressed in vivo tumor growth, and WNT10b expression and β-catenin signaling activities in tumor tissues were suppressed by miR-148a overexpression. In the clinical samples, miR-184a was found to be down-regulated in CRC tissues, down-regulation of miR-148a predicted poor prognosis in CRC patients. In conclusion, our study for the first time enriched the cisplatin-resistant CRC cells with enhanced stem cell marker expression from sphere-forming and chemo-resistant SW480-derived tumor xenografts in immune-deficient mice, and miR-148a suppressed the expression of stem cell markers, increased chemo-sensitivity, cell invasion and migration at least partly via regulating WNT10b and β-catenin signaling pathway.

Cancer stem cells and tumorigenesis

Cancer is one of the most serious diseases all over the world, and the cancer stem cell (CSC) model accounts for tumor initiation, metastasis, drug resistance, and relapse. The CSCs within tumor bulk have the capacity to self-renew, differentiate, and give rise to a new tumor. The self-renewal of CSCs is precisely regulated by various modulators, including Wnt/β-catenin signaling, Notch signaling, Hedgehog signaling, transcription factors, chromatin remodeling complexes, and non-coding RNAs. CSCs reside in their niches that are also involved in the self-renewal maintenance of CSCs and protection of CSCs from chemotherapy, radiotherapy, and even endogenous damages. Moreover, CSCs can also remodel their niches to initiate tumorigenesis. The mutual interactions between CSCs and their niches play a critical role in the regulation of CSC self-renewal and tumorigenesis as well. Many surface markers of CSCs have been identified, and these markers become first choices for CSC targeting. Due to heterogeneity and plasticity, targeting CSCs is still a big challenge for tumor elimination. In this review, we summarize recent progresses on the biological features of CSCs and targeting strategies against CSCs.

Upsetting the Balance: When Viruses Manipulate Cell Polarity Control

The central importance of cell polarity control is emphasized by the frequency with which it is targeted by many diverse viruses. It is clear that in targeting key polarity control proteins, viruses affect not only host cell polarity, but also influence many cellular processes, including transcription, replication, and innate and acquired immunity. Examination of the interactions of different virus proteins with the cell and its polarity controls during the virus life cycles, and in virally‐induced cell transformation shows ever more clearly how intimately all cellular processes are linked to the control of cell polarity.

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Multiple viruses target cell polarity.

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Viral targeting of polarity frequently occurs through PDZ recognition.

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Biological effects include immune-avoidance, cell proliferation and apoptosis inhibition.

Chondrosarcoma-like metastasis from a poorly differentiated uterine cervical squamous cell carcinoma. A unique morphology and diagnostic pitfall in cytology

Rare cases of metastatic squamous cell carcinoma with chondroid differentiation from esophageal primary have been reported but none from the uterine cervix. Given the rarity of this phenomenon and potential diagnostic pitfall, we present this unusual case. The patient is a 25-year-old woman who presented with shortness of breath. Computerized tomography (CT) showed several lung and pleural-based nodules. CT-guided core biopsy with touch preparations were performed on the pleural-based nodule. The touch preparations showed large, spindle-to-oval shaped cells with pleomorphic nuclei embedded in metachromatic chondroid stroma. The core biopsies also showed predominantly round-to-spindle shaped cells with hyperchromatic nuclei and prominent nucleoli embedded in a cartilaginous matrix. Her past medical history is significant for a poorly differentiated squamous cell carcinoma of the cervix, which on review showed a typical non-keratinizing squamous cell carcinoma without sarcomatous differentiation. Immunohistochemical stains performed on the pleural-based mass showed tumor positivity for AE1/AE3, CK5/6, p16, and S-100. Similar results were seen when the cervical tumor was stained retrospectively. Human papilloma virus (HPV) in situ hybridization performed on both the pleural-based mass and cervical tumor detected the presence of high-risk HPV subtypes including 16 and 18. These findings supported a lung metastasis from the prior cervical carcinoma. This case emphasizes that cervical carcinoma can develop mesenchymal (chondrosarcomatous) differentiation in metastasis even in tumors presenting with pure epithelial phenotype. Awareness of this occurrence especially on limited cytology material, knowledge of the prior history and use of ancillary tests are extremely helpful in arriving at the correct diagnosis. Diagn. Cytopathol. 2017;45:750-753. © 2017 Wiley Periodicals, Inc.

Distance in cancer gene expression from stem cells predicts patient survival

The degree of histologic cellular differentiation of a cancer has been associated with prognosis but is subjectively assessed. We hypothesized that information about tumor differentiation of individual cancers could be derived objectively from cancer gene expression data, and would allow creation of a cancer phylogenetic framework that would correlate with clinical, histologic and molecular characteristics of the cancers, as well as predict prognosis. Here we utilized mRNA expression data from 4,413 patient samples with 7 diverse cancer histologies to explore the utility of ordering samples by their distance in gene expression from that of stem cells. A differentiation baseline was obtained by including expression data of human embryonic stem cells (hESC) and human mesenchymal stem cells (hMSC) for solid tumors, and of hESC and CD34+ cells for liquid tumors. We found that the correlation distance (the degree of similarity) between the gene expression profile of a tumor sample and that of stem cells orients cancers in a clinically coherent fashion. For all histologies analyzed (including carcinomas, sarcomas, and hematologic malignancies), patients with cancers with gene expression patterns most similar to that of stem cells had poorer overall survival. We also found that the genes in all undifferentiated cancers of diverse histologies that were most differentially expressed were associated with up-regulation of specific oncogenes and down-regulation of specific tumor suppressor genes. Thus, a stem cell-oriented phylogeny of cancers allows for the derivation of a novel cancer gene expression signature found in all undifferentiated forms of diverse cancer histologies, that is competitive in predicting overall survival in cancer patients compared to previously published prediction models, and is coherent in that gene expression was associated with up-regulation of specific oncogenes and down-regulation of specific tumor suppressor genes associated with regulation of the multicellular state.

miR-148a inhibits self-renewal of thyroid cancer stem cells via repressing INO80 expression

Anaplastic thyroid carcinoma (ATC) is aggressive and lethal with extrathyroidal invasion, distant metastasis, and resistance to conventional therapies. Cancer stem cells (CSCs) are proposed to be responsible for high recurrence rate in ATC. MicroRNAs (miRNAs) have recently been found as an important class of cellular regulators of ATC carcinogenesis. Identification of CSC-related miRNAs and targets is therefore a priority for the development of new therapeutic paradigms. Patient-derived ATC cells were cultured in conditional media on poly-hema-treated dish. ATC CSCs were isolated and enriched through as a series of steps including initial isolation of sphere-forming CSC population, subsequent amplification of this CSC population in a xenograft model treated with cisplatin, and purification of CSCs from xenograft tumors followed by final enrichment using sphere-forming assays. Expression of CSC markers was measured by flow cytometry, immunofluorescence staining, qPCR and western blot analyses. Expression of miRNAs in ATC-CSCs was profiled by microarray analysis. Proliferation and differentiation rates were determined based on the size of spheres formed in vitro and tumors formed in vivo. We successfully isolated and enriched an ATC-CSC population. We identified 17 miRNAs differentially expressed in primary ATC cells vs. ATC-CSCs, among which miRNA-148a was significantly downregulated in ATC-CSCs. Overexpression of miRNA148a in ATC-CSCs induced cell cycle arrest and loss of stem cell characteristics. In addition, we identified INO80 as a target gene of miR-148a. The expression of INO80 was upregulated in ATC-CSCs and downregulated upon miRNA-148 overexpression. Overexpression of miRNA-148a and knockdown of INO80 acted synergistically to decrease the expression of stem cell marker genes as well as to attenuate stem cell-specific properties including the ability to form tumors. This study identified novel contrasting roles for miR-148a and INO80 in the regulation of the stemness of ATC-CSCs and their capacity to initiate tumor formation. Our findings may open a new avenue for therapeutic development against ATC that targets INO80 in the CSCs through enhancing miRNA-148a levels.

Crk-like adapter protein is overexpressed in cervical carcinoma, facilitates proliferation, invasion and chemoresistance, and regulates Src and Akt signaling

Overexpression of Crk-like (CrkL) adapter protein has been implicated in a number of types of human cancer. However, its involvement in human cervical carcinoma remains unclear. The present study aimed to explore the clinical significance and biological characteristics of CrkL in human cervical carcinoma. CrkL protein expression was examined in tissue samples from 92 cases of cervical carcinoma using immunohistochemistry, and was found to be overexpressed in 48.9% (45/92 cases). CrkL was transfected into HeLa and CaSki cervical carcinoma cell lines and its effects on biological behavior were examined. CrkL overexpression was revealed to promote cell proliferation, invasion and chemoresistance. In addition, CrkL overexpression increased the level of Src and Akt phosphorylation. Treatment with the Src inhibitor dasatinib eliminated the effect of CrkL on cell invasion. In conclusion, the current results demonstrate that CrkL is an oncoprotein overexpressed in cervical carcinoma which contributes to malignant cell growth and chemoresistance. In addition, the findings indicate that CrkL promotes cervical cancer cell invasion through a Src-dependent pathway.

Cervical cancer stem cells

The concept of cancer stem cells (CSC) has been established over the past decade or so, and their role in carcinogenic processes has been confirmed. In this review, we focus on cervical CSCs, including (1) their purported origin, (2) markers used for cervical CSC identification, (3) alterations to signalling pathways in cervical cancer and (4) the cancer stem cell niche. Although cervical CSCs have not yet been definitively identified and characterized, future studies pursuing them as therapeutic targets may provide novel insights for treatment of cervical cancer.

Doxycycline Induces Apoptosis and Inhibits Proliferation and Invasion of Human Cervical Carcinoma Stem Cells

Background

Cancer stem cells (CSCs) are proposed to be responsible for high recurrence rate in cervical carcinoma. Reagents that can suppress the proliferation and differentiation of CSCs would provide new opportunities to fight against tumor recurrence. Doxycycline has been reported as a potential anti-cancer compound. However, few studies investigated its inhibitory effect against cervical cancer stem cells.

Methods

HeLa cells were cultured in cancer stem cell conditional media in a poly-hema-treated dish. In this non-adhesive culture system, HeLa cells were treated with cisplatin until some cells survived and formed spheroids, which were then collected and injected into the immunodeficient mice. Cisplatin was administered every three days for five times. The tumor xenografts with CSC enrichment were cultured in cancer stem cell specific medium again to form tumorsphere, which we called HeLa-CSCs. Expression of cancer stem cell markers in HeLa-CSCs was measured by flow cytometry and qPCR. HeLa-CSCs were then treated with doxycycline. Proliferation and differentiation rates were determined by the size of spheres formed in vitro and tumor formed in vivo.

Results

We developed a new strategy to selectively enrich CSCs from human cervical carcinoma cell line HeLa, and these HeLa-CSCs are CD133+/CD49f+ cell populations with significantly enhanced expression of stem cell markers. When these HeLa-CSCs were treated with doxycycline, the colony formation, proliferation, migration and invasion, and differentiation were all suppressed. Meanwhile, stem cell markers SOX-2, OCT-4, NANOG, NOTCH and BMI-1 decreased in doxycycline treated cells, so as the surface markers CD133 and CD49f. Furthermore, proliferation markers Ki67 and PCNA were also decreased by doxycycline treatment in the in vivo xenograft mouse model.

Conclusions

Cancer stem cells are enriched from sphere-forming and chemoresistant HeLa-derived tumor xenografts in immunodeficient mice. Doxycycline inhibits proliferation, invasion, and differentiation, and also induces apoptosis of these HeLa-CSCs in vitro and in vivo.

Cervical cancer stem cells: opportunities and challenges

INTRODUCTION

Cervical cancer remains a leading cause of cancer-related deaths in women in spite of screening and vaccination programs. The current treatment strategies including chemotherapy and surgery could only prolong the patient's survival rather than provide a permanent cure. In case of advanced cervical cancer, radical surgery remains the only option which not only affects the child-bearing ability of the patient, but also comes with a continual risk of recurrence of the disease. Hence, there is a need to develop innovative therapeutics. The cancer stem cell hypothesis states that a tumor has a hierarchical cellular structure in which only a small subpopulation, referred to as cancer stem cells (CSCs), is capable of tumorigenesis. The CSCs possess the stem-like properties of self-renewal and can differentiate into non-stem tumor cells.

RESULTS

A large number of studies suggest that CSCs are resistant to the conventional therapies used for cancer treatment. These therapies rather enrich the proportion of CSCs in the tumor by eliminating non-stem tumor cells, thereby causing enhanced drug resistance resulting in relapse of the disease. This makes CSCs as the most likely targets for therapeutic intervention. Also, the increase in the proportion of CSCs in patient samples is associated with poor survival rate, thus highlighting their potential role as prognostic biomarker.

CONCLUSION

The CSCs have been identified and characterized in cervical cancer cell lines, but there are hardly any reports of CSCs in cervical cancer patient samples. This review highlights the current status of research on cervical CSCs, their clinical significance and the challenges in the field.