Gene expression changes in residual advanced cervical cancer after radiotherapy: indicators of poor prognosis and radioresistance?

Alterations in Blood and Hippocampal mRNA and miRNA Expression, Along with Fat Deposition in Female B6C3F1 Mice Continuously Exposed to Prenatal Low-Dose-Rate Radiation and Their Comparison with Male Mice

Our recent study revealed that continuous prenatal low-dose-rate irradiation did not induce cellular changes in the dentate gyrus of the hippocampus in male B6C3F1 mice exposed to gamma rays during prenatal development. However, changes in body weight, body mass index (BMI), locomotor ability, and mRNA and miRNA expressions in the hippocampus and blood were observed. To investigate potential sex differences in the effects of prenatal gamma irradiation, we conducted a parallel study on female B6C3F1 mice. The results showed significant reductions in the weight of the lungs and left kidney in prenatally irradiated female offspring, accompanied by significantly increased fat deposits in the mesentery, retroperitoneal, and left perigonadal areas. Despite these systemic changes, no cellular alterations were observed in the subgranular zone (immature neurons) or the hilus of the dentate gyrus (mature neurons and glial cells, including astrocytes, microglia, and oligodendrocyte progenitor cells). However, significant increases in hippocampal mRNA expression were detected for genes such as H2bc24, Fos, Cd74, Tent5a, Traip, and Sap25. Conversely, downregulation of mRNAs Inpp5j and Gdf3 was observed in whole blood. A Venn diagram highlighted the differential expression of two mRNAs, Ttn and Slc43a3, between the hippocampus and whole blood. Comparisons between prenatally irradiated male and female B6C3F1 mice revealed sex-specific differences. In whole blood, 4 mRNAs (Scd1, Cd59b, Vmn1r58, and Gm42427) and 1 miRNA (mmu-miR-8112) exhibited differential expression. In the hippocampus, 12 mRNAs and 2 novel miRNAs were differentially expressed between the sexes. qRT-PCR analysis validated the upregulation of H2bc24, Fos, Cd74, and Tent5a in the female hippocampus. These gene expression changes may be associated with the increased fat deposition observed following chronic low-dose-rate gamma irradiation exposure. This study underscores the importance of investigating sex-specific biological responses to prenatal gamma irradiation and highlights potential molecular pathways linked to observed physiological changes.

Identifying hub genes for chemo-radiotherapy sensitivity in cervical cancer: a bi-dataset in silico analysis

PURPOSE

To identify the hub genes that associated with chemo-radiotherapy sensitivity for cervical cancer and to explore the relationship between hub genes and various cellular processes and potential mechanism of cervical cancer.

METHODS

The gene expression data of 21 patients with CESC and the mRNA expression profiles of 296 patients with CESC were obtained from the Gene Expression Omnibus(GEO) and The Cancer Genome Atlas (TCGA) databases, respectively. The potential functions and regulatory mechanisms of differentially expressed genes (DEGs) were identified using GO and KEGG enrichment analyses. Hub genes were identified using random survival forest analysis. The relationship between hub genes and various cellular processes was comprehensively analyzed. The expression of hub genes was assessed using clinical data extracted from the Human Protein Atlas (HPA) database.

RESULTS

A total of 139 and 13 DEGs were found to be upregulated and downregulated, respectively, in CESC. The six hub genes, namely, SELP, PIM2, CCL19, SDS, NRP1, and SF3A2, were significantly correlated with immune cell infiltration, chemotherapy sensitivity, disease-related genes, and enriched signaling pathways (all p-value < 0.05). A nomogram and calibration curve were generated using the six hub genes to predict prognosis with high accuracy. A regulatory network comprising TFs (ZBTB3) and mRNAs (NRP1/PIM2/SELP) and several competitive endogenous RNA (ceRNA) networks comprising mRNAs, miRNAs, and lncRNAs were constructed. Data from HPA indicated that the protein expression of the six hub genes differed significantly between patients with CESC and healthy individuals.

CONCLUSION

Upregulation of SELP, PIM2, CCL19, SDS, NRP1, and SF3A2 is associated with radiotherapy sensitivity and is involved in various cellular processes in CESC. These six genes may serve as biomarkers for predicting the radiotherapy response and prognosis in patients with CESC.

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.

Gene Expression Analysis for Uterine Cervix and Corpus Cancer Characterization

The analysis of gene expression quantification data is a powerful and widely used approach in cancer research. This work provides new insights into the transcriptomic changes that occur in healthy uterine tissue compared to those in cancerous tissues and explores the differences associated with uterine cancer localizations and histological subtypes. To achieve this, RNA-Seq data from the TCGA database were preprocessed and analyzed using the KnowSeq package. Firstly, a kNN model was applied to classify uterine cervix cancer, uterine corpus cancer, and healthy uterine samples. Through variable selection, a three-gene signature was identified (VWCE, CLDN15, ADCYAP1R1), achieving consistent 100% test accuracy across 20 repetitions of a 5-fold cross-validation. A supplementary similar analysis using miRNA-Seq data from the same samples identified an optimal two-gene miRNA-coding signature potentially regulating the three-gene signature previously mentioned, which attained optimal classification performance with an 82% F1-macro score. Subsequently, a kNN model was implemented for the classification of cervical cancer samples into their two main histological subtypes (adenocarcinoma and squamous cell carcinoma). A uni-gene signature (ICA1L) was identified, achieving 100% test accuracy through 20 repetitions of a 5-fold cross-validation and externally validated through the CGCI program. Finally, an examination of six cervical adenosquamous carcinoma (mixed) samples revealed a pattern where the gene expression value in the mixed class aligned closer to the histological subtype with lower expression, prompting a reconsideration of the diagnosis for these mixed samples. In summary, this study provides valuable insights into the molecular mechanisms of uterine cervix and corpus cancers. The newly identified gene signatures demonstrate robust predictive capabilities, guiding future research in cancer diagnosis and treatment methodologies.

Single-nucleus RNA sequencing and deep tissue proteomics reveal distinct tumour microenvironment in stage-I and II cervical cancer

BACKGROUND

Cervical cancer (CC) is the 3rd most common cancer in women and the 4th leading cause of deaths in gynaecological malignancies, yet the exact progression of CC is inconclusive, mainly due to the high complexity of the changing tumour microenvironment (TME) at different stages of tumorigenesis. Importantly, a detailed comparative single-nucleus transcriptomic analysis of tumour microenvironment (TME) of CC patients at different stages is lacking.

METHODS

In this study, a total of 42,928 and 29,200 nuclei isolated from the tumour tissues of stage-I and II CC patients and subjected to single-nucleus RNA sequencing (snRNA-seq) analysis. The cell heterogeneity and functions were comparatively investigated using bioinformatic tools. In addition, label-free quantitative mass spectrometry based proteomic analysis was carried out. The proteome profiles of stage-I and II CC patients were compared, and an integrative analysis with the snRNA-seq was performed.

RESULTS

Compared with the stage-I CC (CCI) patients, the immune response relevant signalling pathways were largely suppressed in various immune cells of the stage-II CC (CCII) patients, yet the signalling associated with cell and tissue development was enriched, as well as metabolism for energy production suggested by the upregulation of genes associated with mitochondria. This was consistent with the quantitative proteomic analysis that showed the dominance of proteins promoting cell growth and intercellular matrix development in the TME of CCII group. The interferon-α and γ responses appeared the most activated pathways in many cell populations of the CCI patients. Several collagens, such as COL12A1, COL5A1, COL4A1 and COL4A2, were found significantly upregulated in the CCII group, suggesting their roles in diagnosing CC progression. A novel transcript AC244205.1 was detected as the most upregulated gene in CCII patients, and its possible mechanistic role in CC may be investigated further.

CONCLUSIONS

Our study provides important resources for decoding the progression of CC and set the foundation for developing novel approaches for diagnosing CC and tackling the immunosuppressive TME.

Elevated CXCL12 in the plasma membrane of locally advanced rectal cancer after neoadjuvant chemoradiotherapy: a potential prognostic marker

Background: Neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) has been shown to improve sphincter preservation and local pelvic control, but the efficacy of nCRT plateaus due to metastasis. CXC chemokine ligand 12 (CXCL12) has a critical impact on cancer development and metastasis.

Methods: By investigating public databases containing LARC patient data, CXCL12, CXCR4 and FAPα expression was analyzed via the Tumor Immune Estimation Resource (TIMER) and GSEA. Immunohistochemistry was applied to a total of 121 surgically resected specimens consisting of 61 LARCs after nCRT and 60 LARCs with no nCRT and 16 cases with endoscopic resection of high-grade colorectal adenoma.

Results: By investigating public databases containing LARC patient data, CXCL12 expression is correlated with poor prognosis, immune cell infiltration, epithelial- mesenchymal transition, and angiogenesis in LARC. Furthermore, radiation selectively induced CXCL12, CXCR4 and FAPα expression in tumor tissues. Immunohistochemistry results showed that the levels of CXCL12, CXCR4, and FAPα in LARC cells after nCRT were higher than in LARC cells untreated with nCRT (p < 0.001 for each). Elevated levels of CXCL12 in the plasma membrane of LARC cells after nCRT demonstrated an association with the period of freedom from recurrence (FFR) in univariate and multivariate survival analyses (p = 0.005 and p = 0.031, respectively).

Conclusions: The expression of CXCL12 may influence the survival and invasive properties of LARC cells during nCRT and promote cancer recurrence. We suggest that CXCL12 expression in the plasma membrane of radioresistant LARC cells may be a predictive factor of recurrence and a viable therapeutic strategy to control radioresistant LARC recurrence.

The Help of HPV Integration Testing to Avoid the Misdiagnosis of a Patient with Stage Ia1 Cervical Cancer: A Case Report and Literature Review

Screening and prevention in the early stage of cervical cancer could improve the 5-year survival rate of cervical cancer by up to 90%. The occurrence rate of human papillomavirus (HPV) integration has gradually increased with the development of cervical lesions. Here, we report the case of a 43-year-old woman diagnosed with chronic cervicitis based on cervical biopsy results. After medical consultation, surgery was recommended to the patient considering her 64 HPV integration sites and other biochemical and clinical test results. The pathology result of the conical biopsy obtained during operation confirmed that both her cervix and the glands had high-grade squamous intraepithelial lesion or cervical intraepithelial neoplasia III (HSIL/CIN III). The patient underwent uterectomy and bilateral salpingectomy and was discharged thereafter. The diagnosis of the patient was revised to stage Ia1 cervical cancer. The number of HPV integration sites is suggested to be an auxiliary indicator in the early screening of cervical cancer for predicting high-grade CIN and invasive cervical cancer.

IL-11 mediates the Radioresistance of Cervical Cancer Cells via the PI3K/Akt Signaling Pathway

Cervical cancer is one of the most common malignant tumors in the female reproductive system. Radioresistance remains a significant factor that limits the efficacy of radiotherapy for cervical cancer. Interleukin-11 (IL-11) has been reported to be upregulated in various types of human cancer and correlate with clinical stage and poor survival. However, the exact effects and mechanisms of IL-11 in the radioresistance of cervical cancer have not yet been defined. In this research, TCGA databases revealed that IL-11 expression was upregulated in cervical cancer tissues and was associated with clinical stages and poor prognosis in cervical cancer patients. We discovered that IL-11 concentration was significantly upregulated in radioresistant cervical cancer cells. Knocking down IL-11 in Hela cells could reduce clonogenic survival rate, decrease cell viability, induce G2/M phase block, and facilitate cell apoptosis. In contrast, Exogeneous IL-11 in C33A cells could upregulate clonogenic survival rate, increase cell viability, curb G2/M phase block, and cell apoptosis. Mechanistic investigations showed that radioresistance conferred by IL-11 was attributed to the activation of the PI3K/Akt signaling pathway. Altogether, our results demonstrate that IL-11 might be involved in radioresistance, and IL-11 may be a potent radiosensitization target for cervical cancer therapy.

Knockdown of Ubiquitin-Specific Protease 53 Enhances the Radiosensitivity of Human Cervical Squamous Cell Carcinoma by Regulating DNA Damage-Binding Protein 2

Background:

Cervical cancer ranks fourth in incidence and mortality among women. Ubiquitin-specific protein 53 binds to damage-specific DNA binding protein 2 and affects the biological properties of colon cancer. Damage-specific DNA binding protein is involved in nucleotide excision repair, which can repair DNA damage. However, the mechanism by which ubiquitin-specific protein 53 regulates the radiosensitivity of cervical cancer through damage-specific DNA binding protein remains unclear.

Methods:

Tissue samples from 40 patients with cervical squamous cell carcinoma who received radiotherapy were examined by immunohistochemistry to detect the expression of ubiquitin-specific protein 53, and clinical data were collected for statistical analysis. The cell cycle was detected by flow cytometry in Siha cells transfected with Si-USP53 and exposed to 8 Gy irradiation. Cell viability was determined by the CCK8 method in cells transfected with Si-USP53 and exposed to 0, 2, 4, 6, 8, or 10 Gy. The expression of damage-specific DNA binding protein, cyclin-dependent kinase 1, and cell cycle checkpoint kinase 2 was detected in cells transfected with Si-USP53.

Results:

The expression of ubiquitin-specific protein 53 in the tissues of patients with cervical squamous cell carcinoma was correlated with the sensitivity to radiotherapy. Knockdown of ubiquitin-specific protein 53 in Siha cells downregulated damage-specific DNA binding protein and caused G2/M cell cycle arrest and decreased the survival rate of cells in response to radiation.

Conclusion:

Ubiquitin-specific protein 53–induced cell cycle arrest and affected the radiotherapy sensitivity of tumors through damage-specific DNA binding protein.

TAF1A and ZBTB41 serve as novel key genes in cervical cancer identified by integrated approaches

Cervical cancer (CC) is the second most common cancer and the leading cause of cancer mortality in women. Numerous studies have found that the development of CC was associated with multiple genes. However, the mechanisms on gene level are enigmatic, hindering the understanding of its functional roles. This study sought to identify prognostic biomarkers of CC, and explore their biological functions. Here we conducted an integrated analysis to screen potential vital genes. Candidate genes were further tested by experiments in clinical specimens and cancer cell line. Then, molecular modeling was used to predict the three-dimensional structure of candidate genes’ proteins, and the interaction pattern was analyzed by docking simulation technique. Among the potential genes identified, we found that TAF1A and ZBTB41 were highly correlated. Furthermore, there was a definite interaction between the proteins of TAF1A and ZBTB41, which was affected by the activity of the p53 signaling pathway. In conclusion, our findings identified TAF1A and ZBTB41 could serve as biomarkers of CC. We confirmed their biological function and deciphered their interaction for the first time, which may be helpful for developing further researches.

Ionizing radiation effects on the tumor microenvironment

The broad use of radiotherapy (RT) in the management of solid human tumors is based on its ability to damage cellular macromolecules, particularly the DNA, effectively inducing growth arrest and cell death locally in irradiated tumor cells. However, bystander effects, such as the transmission of lethal signals between cells via gap junctions or the production of diffusible cytotoxic mediators, can also contribute to the local antineoplastic action of RT. Traditionally, RT has been considered to exert immunosuppressive effects on the host. This idea largely stems from the radiosensitivity of quiescent lymphocytes and on the use of total body irradiation as part of myeloablative conditioning regimens preceding hematopoietic stem cell transplantation. Additionally, the occurrence of the so-called "abscopal effect," where nonirradiated distant lesions display effects of RT response, suggests that RT may also induce tumor immunization. Several RT-induced effects on cancer, immune and stromal cells, contribute to the abscopal effect: (1) induction of "immunogenic cell death", with release of tumor-associated antigens, (2) alterations of cancer cell immunophenotype, and (3) modulation of the tumor microenvironment. Damage and death of cancer cells leads to the surface exposure of immunogenic molecules as well as the release of damage associated molecular patterns such as adenosine triphosphate or High-Mobility-Group-Protein B1, and potentially tumor antigens that activate the innate and adaptive immune systems. Moreover, nuclear release and cytoplasmic sensing of altered nucleic acids via cyclic GMP-AMP Synthase/Stimulator of Interferon Genes is connected to the secretion of cytokines that support innate and adaptive antitumor immunity. As a result of the above, irradiated tumor cells may potentially act as an "in situ vaccine."

Overexpression of the immediate early response 5 gene increases the radiosensitivity of HeLa cells

The effects of the immediate early response 5 (IER5) gene on the sensitivity of HeLa cells to radiation remain unclear. In the present study, stably transfected HeLa cells resulting in the knockdown or overexpression of IER5 were investigated. In addition, xenografts of normal, IER5-silenced and -overexpressed HeLa cells were injected into nude mice and examined. The results demonstrated that the radiosensitivity of the IER5-overexpressed HeLa cells was significantly increased compared with that of the normal and IER5-silenced cells. The upregulation of IER5 effectively decreased cell proliferation and IER5 silencing promoted cell proliferation compared with that in the normal HeLa cells. Following irradiation of the cells with IER5 knockdown, cell cycle was arrested at the G₂/M phase and an increase in the proportion of S phase cells was observed. By contrast, the overexpression of IER5 led to an increase in the proportion of G₁ phase cells. Furthermore, the upregulation of IER5 inhibited tumor growth in vivo. The present findings demonstrate that the IER5 gene affects the radiosensitivity of HeLa cells and serves an important role in cell proliferation, suggesting that this gene may be a potential radiotherapeutic target in cervical cancer.

Potential Role of CXCR4 Targeting in the Context of Radiotherapy and Immunotherapy of Cancer

Cancer immunotherapy has been established as standard of care in different tumor entities. After the first reports on synergistic effects with radiotherapy and the induction of abscopal effects-tumor shrinkage outside the irradiated volume attributed to immunological effects of radiotherapy-several treatment combinations have been evaluated. Different immunotherapy strategies (e.g., immune checkpoint inhibition, vaccination, cytokine based therapies) have been combined with local tumor irradiation in preclinical models. Clinical trials are ongoing in different cancer entities with a broad range of immunotherapeutics and radiation schedules. SDF-1 (CXCL12)/CXCR4 signaling has been described to play a major role in tumor biology, especially in hypoxia adaptation, metastasis and migration. Local tumor irradiation is a known inducer of SDF-1 expression and release. CXCR4 also plays a major role in immunological processes. CXCR4 antagonists have been approved for the use of hematopoietic stem cell mobilization from the bone marrow. In addition, several groups reported an influence of the SDF-1/CXCR4 axis on intratumoral immune cell subsets and anti-tumor immune response. The aim of this review is to merge the knowledge on the role of SDF-1/CXCR4 in tumor biology, radiotherapy and immunotherapy of cancer and in combinatorial approaches.

CXCL12 modulates the radiosensitivity of cervical cancer by regulating CD44

The aim of the present study was to investigate the regulation of stromal cell‑derived factor 1 (CXCL12) in the radioresistance of cervical cancer, which was upregulated in tumors in our previous study. A CCK‑8 assay was used to detect cell viability. Flow cytometry was used to measure cell apoptosis and the expression levels of CD44 and CXCR4. ELISA was performed to measure the expression level of CXCL12 protein and CXCL12 mRNA was detected by reverse transcription‑quantitative polymerase chain reaction assays. Cell viability and apoptosis were determined with or without treatment with CXCL12 small interfering (si)RNA to examine the function of CXCL12 in Hela cells. The expression level of CD44 antigen (CD44) and C‑X‑C chemokine receptor type 4 (CXCR4) were measured using flow cytometry in the presence of CXCL12 and irradiation. In the present study, it was demonstrated that inhibition of CXCL12 reduced cell viability and increased cellular apoptosis in Hela cells treated with irradiation. Following treatment with CXCL12 siRNA, the expression level of CD44 was downregulated and the expression level of CXCR4 was upregulated. This effect of regulation additionally occurred in the presence of irradiation. In conclusion, the present data demonstrated that CXCL12 served an important role in the radioresistance of cervical cancer, suggestinh a novel therapeutic target.

miR-381-3p restrains cervical cancer progression by downregulating FGF7

This study aimed at elucidating the molecular mechanism of miR-381-3p in cervical cancer progression, which may provide a novel therapeutic target for patients with cervical cancer. The expression of miR-381-3p was confirmed by quantitative reverse transcription polymerase chain reaction. Microarray analysis was conducted to screen out differentially expressed genes, and the target gene of microRNA (miRNA) was predicted on TargetScan. Dual-luciferase reporter assay then verified the targeting relationship between miR-381-3p and FGF7. The protein expression of FGF7 was examined via Western blot assay. Colony formation assay was used to detect the cell proliferation, while flow cytometry was used to analyze cell cycle and apoptosis. The influence of miR-381-3p and FGF7 on cell migration and invasion was confirmed by transwell migration/invasion assay. Finally, we demonstrated that miR-381-3p was lowly expressed, while FGF7 was highly expressed in cervical cancer cells. There was a direct target relationship and a negative correlation between miR-381-3p and FGF7. miR-381-3p could downregulate FGF7 expression, inhibiting cell proliferation and metastasis, and inducing cell cycle arrest and apoptosis in cervical cancer.

[Inflammatory and immune biomarkers of radiation response]

In radiotherapy, the treatment is adapted to each individual to protect healthy tissues but delivers most of time a standard dose according to the tumor histology and site. The only biomarkers studied to individualize the treatment are the HPV status with radiation dose de-escalation strategies, and tumor hypoxia with dose escalation to hypoxic subvolumes using FMISO- or FAZA-PET imaging. In the last decades, evidence has grown about the contribution of the immune system to radiation tumor response. Many preclinical studies have identified some of the mechanisms involved. In this context, we have realised a systematic review to highlight potential inflammatory and immune biomarkers of radiotherapy response. Some are inside the tumor microenvironment, as lymphocyte infiltration or PD-L1 expression, others are circulating biomarkers, including different types of hematological cells, cytokines and chemokines.

Distributions of manganese in diverse human cancers provide insights into tumour radioresistance

We show that measuring manganese levels in tumours of cancer patients is predictive for their radiation treatment.

Evaluation of short- and long-term efficacy of chemoradiotherapy for advanced cervical cancer using HSP70 protein combined with multimodal MRI

This study aims to evaluate the efficacy of chemoradiotherapy for advanced cervical cancer using heat shock protein 70 (HSP70) combined with multimodal MRI. The protein expressions of HSP70 in biopsy specimens obtained from 101 patients with cervical cancer were detected by immunohistochemistry. Plain MRI scan, DWI, DCE-MR, and MRS were performed before and after a period of 6 months of chemoradiotherapy. All patients were assigned into the complete response (CR) and partial response (PR) groups. HSP70 protein expression, tumor diameter, and tumor volume were lower in the CR group than in the PR group. The rate of tumor shrinkage, relative positive enhancement integral (rPEI), relative maximum slope of decrease (rMSD), relative signal enhancement ratio at 60 s (rSER₆₀ ) and maximum SER (rSER_max ), mean apparent diffusion coefficient (ADC_mean ) and minimum ADC value (ADC_min ) values in the CR group were higher than those in the PR group. Tumor diameter and volume, rSER₁₅ and rSER₃₀ were reduced after chemoradiotherapy, while rMSD, rSER_max , time to peak (TTP), ADC_mean and ADC_min were higher after the treatment. The receiver operating characteristic (ROC) curves indicated that HSP70 expression, tumor diameter, rPEI, ADC_mean and Cho peak showed the better chemoradiotherapy efficacy. Our data demonstrates that HSP70 protein combined with multimodal MRI may accurately evaluate the chemoradiotherapy efficacy of patients with advanced cervical cancer. The recurrence of cervical cancer significantly decreased in patients with negative expression of HSP70 and HSP70 protein detection provides potential therapy for the prevention, diagnosis, and prognosis of cervical cancer.

miR-668 enhances the radioresistance of human breast cancer cell by targeting IκBα

BACKGROUND

A large proportion of breast cancer patients are resistant to radiotherapy, which is a mainstay treatment for this malignancy, but the mechanisms of radioresistance remain unclear.

METHODS AND MATERIALS

To evaluate the role of miRNAs in radioresistance, we established two radioresistant breast cancer cell lines MCF-7R and T-47DR derived from parental MCF-7 and T-47D. Moreover, miRNA microarray, quantitative RT-PCR analysis, luciferase reporter assay and western blotting were used.

RESULTS

We found that miR-668 was most abundantly expressed in radioresistant cells MCF-7R and T-47DR. miR-668 knockdown reversed radioresistance of MCF-7R and T-47DR, miR-668 overexpression enhanced radioresistance of MCF-7 and T-47D cells. Mechanically, bioinformatics analysis combined with experimental analysis demonstrated IκBα, a tumor-suppressor as well as an NF-κB inhibitor, was a direct target of miR-668. Further, miR-668 overexpression inhibited IκBα expression, activated NF-κB, thus, increased radioresistance of MCF-7 and T-47D cells. Conversely, miR-668 knockdown restored IκBα expression, suppressed NF-κB, increased radiosensitivity of MCF-7R and T-47DR cells.

CONCLUSION

Our findings suggest miR-668 is involved in the radioresistance of breast cancer cells and miR-668-IκBα-NF-κB axis may be a novel candidate for developing rational therapeutic strategies for human breast cancer treatment.

A meta-analysis of CXCL12 expression for cancer prognosis

Background:

CXCL12 (SDF1) is reported to promote cancer progression in several preclinical models and this is corroborated by the analysis of human tissue specimens. However, the relationship between CXCL12 expression and cancer survival has not been systematically assessed.

Methods:

We conducted a systematic review and meta-analysis of studies that evaluated the association between CXCL12 expression and cancer survival.

Results:

Thirty-eight studies inclusive of 5807 patients were included in the analysis of overall, recurrence-free or cancer-specific survival, the majority of which were retrospective. The pooled hazard ratios (HRs) for overall and recurrence-free survival in patients with high CXCL12 expression were 1.39 (95% CI: 1.17–1.65, P=0.0002) and 1.12 (95% CI: 0.82–1.53, P=0.48) respectively, but with significant heterogeneity between studies. On subgroup analysis by cancer type, high CXCL12 expression was associated with reduced overall survival in patients with oesophagogastric (HR 2.08; 95% CI: 1.31–3.33, P=0.002), pancreatic (HR 1.54; 95% CI: 1.21–1.97, P=0.0005) and lung cancer (HR 1.37; 95% CI: 1.08–1.75, P=0.01), whereas in breast cancer patients high CXCL12 expression conferred an overall survival advantage (HR 0.5; 95% CI: 0.38–0.66, P<0.00001).

Conclusions:

Determination of CXCL12 expression has the potential to be of use as a cancer biomarker and adds prognostic information in various cancer types. Prospective or prospective–retrospective analyses of CXCL12 expression in clearly defined cancer cohorts are now required to advance our understanding of the relationship between CXCL12 expression and cancer outcome.

CXCL12 is a key regulator in tumor microenvironment of cervical cancer: an in vitro study

CXCL12 is a small pro-inflammatory chemo-attractant cytokine which signals through chemokine receptor CXCR4. The importance of CXCL12/CXCR4 axis is coming to the fore in several divergent signaling pathway-initiating signals related to cell survival and/or proliferation and cancer metastasis. In the present study we have investigated whether deregulation in CXCR4 signaling (as a consequence of deregulated expression of CXCL12) modulate the metastatic potential of cervical carcinoma cells. We demonstrate that CXCL12 is frequently down regulated and its promoter is hypermethylated in cervical cancer cell lines and primary tumor biopsies. Exogenous treatment of cervical cancer cell lines (HeLa, SiHa and C-33A) with recombinant CXCL12 inhibited the metastasis promoting cell migration, cell invasion and anchorage independent cell growth events. Although this study will need further in vivo validation, our observations suggest that (a) silencing of CXCL12 in cervical cancer cells may be critical in migration and invasion, the key events in cancer cell metastases; (b) cervical cancer cells having down regulated CXCL12 are more prone to being attracted to CXCL12 expressed at secondary sites of metastases; and (c) CXCL12 inhibits anchorage independent cell growth via anoikis. These findings suggest the tumor suppressor functions of CXCL12 in cervical cancer.

MALAT1-miR-124-RBG2 axis is involved in growth and invasion of HR-HPV-positive cervical cancer cells

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT 1) is a large, infrequently spliced non-coding RNA aberrantly expressed in cervical cancer. But the molecular mechanisms of its oncogenic role are still not quite clear. The present study explored whether there is a competing endogenous RNAs (ceRNAs) mechanism involved in the oncogenic effect of MALAT1. MALAT1 expression was firstly verified in high-risk human papillomavirus (HR-HPV)-positive tumor tissues and cell lines. Its regulation over miR-124 and the downstream target of miR-124 in regulation of growth, invasion, and apoptosis of the cancer cells are also studied. Findings of this study confirmed higher MALAT1 expression in HR-HPV (+) cervical cancer. Knockdown of endogenous MALAT1 significantly reduced cell growth rate and invasion and increased cell apoptosis of Hela and siHa cells. Besides, knockdown of MALAT1 increased the expression of miRNA-124, while ectopic expression of miR-124 decreased MALAT1 expression. In addition, we also verified a direct interaction between miR-124 and 3'UTR of GRB2. MALAT1 can indirectly modulate GRB2 expression via competing miR-124. Knockdown of GRB2 reduced cell invasion and increased cell apoptosis. In conclusion, MALAT1 can promote HR-HPV (+) cancer cell growth and invasion at least partially through the MALAT1-miR-124-RBG2 axis. This finding might provide some useful evidence about the lncRNA interaction regulatory network in tumorigenesis cervical cancer.