Role of Krüppel-Like Factor 4 in the Maintenance of Chemoresistance of Anaplastic Thyroid Cancer

The Absence of Thyroid-Stimulating Hormone Receptor Expression on Natural Killer T Cells: Implications for the Immune-Endocrine Interaction

The expression of thyroid-stimulating hormone receptor (TSHR) has been documented on various immune cells, including B lymphocytes, T lymphocytes, Natural Killer (NK) cells, monocytes, and dendritic cells (DCs). Natural Killer T (NKT) cells serve as a crucial link between innate and adaptive immunity, playing significant roles in immunological interactions and autoimmune diseases. The aim of the present study was to evaluate the presence of TSHR on NKT cells. Our research involved patients with thyroid disease, as well as healthy controls. Peripheral blood mononuclear cells (PBMCs) and, thereafter, NKT cells were isolated from 86 patients with benign nodular thyroid disease with and without autoimmune thyroid disease (AITD) (28 and 56 cases, respectively), and TSHR expression was analyzed using fluorescence-activated cell sorting (FACS). In order to confirm the results, the reverse-transcription polymerase chain reaction (RT-PCR) method was used in cells obtained from healthy individuals. Our findings obtained with application of the FACS method revealed that TSHR is not expressed on NKT cells in either AITD or non-AITD patients, though TSHR was detected in the total PBMC population (TSHR+ cells 2.77%). The absence of TSHR on NKT cells was further confirmed with RT-PCR in healthy individuals (p < 0.0001). These results questioned the previously suggested direct influence of NKT cells on AITD development.

Unveil Intrahepatic Cholangiocarcinoma Heterogeneity through the Lens of Omics and Multi-Omics Approaches

Intrahepatic cholangiocarcinoma (iCCA) is recognized worldwide as the second leading cause of morbidity and mortality among primary liver cancers, showing a continuously increasing incidence rate in recent years. iCCA aggressiveness is revealed through its rapid and silent intrahepatic expansion and spread through the lymphatic system leading to late diagnosis and poor prognoses. Multi-omics studies have aggregated information derived from single-omics data, providing a more comprehensive understanding of the phenomena being studied. These approaches are gradually becoming powerful tools for investigating the intricate pathobiology of iCCA, facilitating the correlation between molecular signature and phenotypic manifestation. Consequently, preliminary stratifications of iCCA patients have been proposed according to their "omics" features opening the possibility of identifying potential biomarkers for early diagnosis and developing new therapies based on personalized medicine (PM). The focus of this review is to provide new and advanced insight into the molecular pathobiology of the iCCA, starting from single- to the latest multi-omics approaches, paving the way for translating new basic research into therapeutic practices.

Kruppel-like factor 13 acts as a tumor suppressor in thyroid carcinoma by downregulating IFIT1

BACKGROUND

Kruppel-like factor 13 (KLF13) is a transcription factor and plays an important role in carcinogenesis. However, the significance of KLF13 in thyroid carcinoma (THCA) is underdetermined. In this study, we aimed to explore the clinical relevance and function of KLF13 in the progress of THCA.

METHODS

The expression of KLF13 in thyroid carcinoma and normal tissue was investigated by qPCR and IHC assay. The expression of KLF13 and IFIT1 in cell samples was investigated with Western blot assay. Cell proliferation ability was detected with CCK8 and colony formation assay. Cell growth in vivo with or without KLF13 overexpression was evaluated on a xenograft model. Cell migration ability was measured with Transwell assay. Cell cycle was detected with flow cytometer. The downstream genes of KLF13 were screened using RNA-seq assay. Luciferase activity was employed to assess the transcriptional regulation of KLF13 on IFIT1 promoter.

RESULTS

KLF13 expression was downregulated in THCA samples. KLF13 knockdown and overexpression promoted and inhibited the proliferation and migration of THCA cells, respectively. The RNA-seq, RT-qPCR and immunoblotting data showed that KLF13 knockdown significantly potentiated IFIT1 expression at both mRNA and protein levels. Luciferase assays showed that KLF13 suppressed the transcription activity of IFIT1 promoter. Besides, IFIT1 upregulation was critical for the proliferation and migration of THCA cell lines. Lastly, silencing of IFIT1 greatly reversed the proliferation and migration induced by KLF13 knockdown.

CONCLUSIONS

In conclusion, KLF13 may function as an anti-tumor protein in THCA by regulating the expression of IFIT1 and offer a theoretical foundation for treating thyroid carcinoma.

Stemness potency and structural characteristics of thyroid cancer cell lines

BACKGROUND

Thyroid cancer is the most frequent type of endocrine malignancy. Thyroid carcinomas are derived from the follicular epithelium and classified as papillary (PTC) (85%), follicular (FTC) (12%), and anaplastic (ATC) (<3%). Thyroid cancer could arise from thyroid cancer stem-like cells (CSCs). CSCs are cancer cells that feature stem-like properties. Kruppel-like factor (KLF4) and Stage-spesific embryonic antigen 1 (SSEA-1) are types of stem cell markers. Filamentous actin (F-actin) is an essential part of the cellular cytoskeleton. The purpose of this study was to evaluate the stem cell potency and the spatial distribution of the cytoskeletal element F-actin in PTC, FTC, and ATC cell lines.

MATERIALS AND METHODS

Normal thyroid cell line (NTC) Nthy-ori-3-1, PTC cell line BCPAP, FTC cell line FTC-133 and ATC cell line 8505c were stained with SSEA-1 and KLF4 for stem cell potency and F-actin for cytoskeleton. The morphological properties of cells were assessed by a scanning electron microscope (SEM) and elemental ratios were compared with EDS.

RESULTS

PTCs had greater percentages of SSEA-1 and KLF4 protein intensity (0.32% and 0.49%, respectively) than NTCs. ATCs had a greater proportion of KLF4 expression (0.8%) than NTCs. NTCs and FTCs had increased F-actin intensity across the cell, but PTCs had the lowest among these four cell lines. NTCs and PTCs, as well as NTCs and FTCs, have statistically identical aspect ratios and round values. These values, however, were statistically different in ATCs.

CONCLUSION

The study of stem cell markers and the cytoskeletal element F-actin in cancer and normal thyroid cell lines may assist in the identification of new therapeutic targets and contribute in the understanding of treatment resistance mechanisms.

DUB3/KLF4 combats tumor growth and chemoresistance in hepatocellular carcinoma

This study aimed to investigate the role of deubiquitinating enzyme 3 (DUB3) in the regulation of Krüppel-like factor 4 (KLF4) expression in hepatocellular carcinoma (HCC). Gain- and loss-of-function assay, luciferase reporter assay, co-immunoprecipitation, and intracellular and extracellular deubiquitination assays were conducted in vitro. A tumor xenograft mouse model was established. The expression of DUB3 and KLF4 was examined in HCC patient specimens. The results showed that DUB3 upregulated KLF4 expression by deubiquitinating and stabilizing KLF4 protein in HCC cells through binding with KLF4. DUB3 inhibited HCC cell proliferation in vitro and tumor growth in vivo while enhancing the chemosensitivity of HCC cells in a KLF4-dependent manner. Furthermore, KLF4 promoted DUB3 transcription by binding to the DUB3 promoter. In HCC patients, DUB3 expression positively correlated with KLF4 expression in HCC tissues. Low DUB3 expression predicted worse overall survival and recurrence in HCC patients. In conclusion, this study revealed a positive DUB3/KLF4 feedback loop that inhibits tumor growth and chemoresistance in HCC. These results suggest that DUB3/KLF4 activation might be a potential therapeutic approach for HCC treatment.

Capsaicin inhibits the stemness of anaplastic thyroid carcinoma cells by triggering autophagy-lysosome mediated OCT4A degradation

Capsaicin (CAP) is a well-known anti-cancer agent. Recently, we reported capsaicin-induced apoptosis in anaplastic thyroid cancer (ATC) cells. It is well accepted that the generation of cancer stem cells (CSCs) is responsible for the dedifferentiation of ATC, the most lethal subtype of thyroid cancer with highly dedifferentiation status. Whether CAP inhibited the ATC growth through targeting CSCs needed further investigation. In the present study, CAP was found to induce autophagy in ATC cells through TRPV1 activation and subsequent calcium influx. Meanwhile, CAP dose-dependently decreased the sphere formation capacity of ATC cells. The stemness-inhibitory effect of CAP was further by extreme limiting dilution analysis (ELDA). CAP significantly decreased the protein level of OCT4A in both 8505C and FRO cells. Furthermore, CAP-induced OCT4A degradation was reversed by autophagy inhibitors 3-MA and chloroquine, BAPTA-AM and capsazepine, but not proteasome inhibitor MG132. Collectively, our study firstly showed CAP suppressed the stemness of ATC cells partially via calcium-dependent autophagic degradation of OCT4A. Our study lent credence to the feasible application of capsaicin in limiting ATC stemness.

Characterisation of Levonorgestrel-Resistant Endometrial Cancer Cells

Background

Endometrial cancer (EC) is the most common gynaecologic malignancy in the developed world, and incidence is increasing in premenopausal women. The levonorgestrel intrauterine system (LNG-IUS) is gaining traction as an alternative treatment for hyperplasia and early-stage EC for women who are unable to undergo surgery. Thirty to 60% of the women do not respond to this treatment, making the unknown mechanisms of levonorgestrel (LNG) resistance a critical obstacle for the conservative management of EC. This study aimed to characterise LNG-IUS treatment resistance in early-stage endometrial cancer in cell-line models.

Methods

LNG-resistant endometrial cancer cell lines (MFE296^R and MFE319^R) and cultures from three early stage endometrial cancer patients were developed. The behavioural profile of MFE296^R and MFE319^R was analysed using proliferation, adhesion, migration (wound healing and transwell) and invasion (spheroid) assays. LNG-sensitive cell lines (MFE296^S and MFE319^S) were compared to LNG^R cell lines (MFE296^R and MFE319^R). A literature search was conducted to identify possible candidate biomarkers of LNG resistance. RT-qPCR was used to analyse the mRNA expression of 17 candidate biomarkers in MFE296^R and MFE319^R. mRNA expression of the top differentially expressed genes was measured using RT-qPCR in primary cultures.

Results

LNG resistance did not affect proliferation or invasion in immortalised endometrial cancer cells. Transwell migration was significantly increased in MFE319^R cells (p=0.03). Cellular adhesion significantly decreased in both MFE296^R cells (p=0.012) and MFE319^R cells (p=0.04). mRNA expression of KLF4 and SATB2 was significantly amplified in MFE296^R and MFE319^R cells. mRNA expression of KLF4 was significantly upregulated LNG-resistant primary cell lines.

Conclusion

LNG-resistant cells may have more oncogenic potential than their LNG-sensitive counterparts. Significant changes in the mRNA expression of KLF4 and SATB2 of LNG-resistant cells is a promising preliminary result in biomarker discovery for guiding LNG-IUS treatment of early stage endometrial cancer.

Application of Proteomics in Cancer: Recent Trends and Approaches for Biomarkers Discovery

Proteomics has become an important field in molecular sciences, as it provides valuable information on the identity, expression levels, and modification of proteins. For example, cancer proteomics unraveled key information in mechanistic studies on tumor growth and metastasis, which has contributed to the identification of clinically applicable biomarkers as well as therapeutic targets. Several cancer proteome databases have been established and are being shared worldwide. Importantly, the integration of proteomics studies with other omics is providing extensive data related to molecular mechanisms and target modulators. These data may be analyzed and processed through bioinformatic pipelines to obtain useful information. The purpose of this review is to provide an overview of cancer proteomics and recent advances in proteomic techniques. In particular, we aim to offer insights into current proteomics studies of brain cancer, in which proteomic applications are in a relatively early stage. This review covers applications of proteomics from the discovery of biomarkers to the characterization of molecular mechanisms through advances in technology. Moreover, it addresses global trends in proteomics approaches for translational research. As a core method in translational research, the continued development of this field is expected to provide valuable information at a scale beyond that previously seen.

3,3'-Diindolylmethane Enhances Paclitaxel Sensitivity by Suppressing DNMT1-Mediated KLF4 Methylation in Breast Cancer

Paclitaxel (PTX) is a first-line chemotherapeutic drug for the treatment of breast cancer, but drug resistance seriously limits its clinical use. The aim of the present work was to explore the effect of 3,3’-diindolylmethane (DIM) on PTX sensitivity and its possible mechanism in breast cancer. The expression of Krüppel-like factor 4 (KLF4) and DNA-methyltransferase 1 (DNMT1) in breast cancer tissues were assessed by immunohistochemistry and Western blotting. The methylation of KLF4 was evaluated by the MassARRAY platform. The lentivirus carrying KLF4 and DNMT1 gene or shRNA targeting DNMT1 were used to overexpress KLF4 or knockdown DNMT1 in MCF-7 and T47D breast cancer cells and the role of KLF4 and DNMT1 in regulation of PTX sensitivity was investigated. The effect of PTX on inhibiting the proliferation of MCF-7 and T47D cells was measured by CCK-8 assay. Flow cytometry was used to examine cell apoptosis. The expression of mRNA and protein was evaluated by qRT-PCR and Western blotting analysis, respectively. Our data showed that the expression of DNMT1 was increased, and the methylation level of CpG sites (−148 bp) in the KLF4 promoter was increased while the KLF4 expression was significantly decreased in breast cancer tissues. Overexpression of KLF4 increased the sensitivity of MCF-7 and T47D cells to PTX. DNMT1 increased the methylation of the KLF4 promoter and decrease the expression of KLF4. Knockdown of DNMT1 increased the sensitivity of MCF-7 and T47D cells to PTX. DIM enhanced the PTX sensitivity of MCF-7 and T47D cells, decreased the expression of DNMT1 and the methylation level of KLF4 promoter, thus increasing the level of KLF4. Furthermore, overexpression of DNMT1 attenuated the effect of DIM on the regulation of PTX sensitivity. Collectively, our data indicated that DNMT1-mediated hypermethylation of KLF4 promoter leads to downregulation of KLF4 in breast cancer. The level of KLF4 is correlated with the sensitivity of MCF-7 and T47D cells to PTX. DIM could enhance the antitumor efficacy of PTX on MCF-7 and T47D cells by regulating DNMT1 and KLF4.

Pluripotency inducing Yamanaka factors: role in stemness and chemoresistance of liver cancer

Introduction: Liver cancer is a major cause of mortality and is characterized by the transformation of cells into an uncontrolled mass of tumor cells with many genetic and epigenetic changes, which lead to the development of tumors. A small subpopulation of cell population known as Cancer Stem Cells (CSCs) is responsible for cancer stemness and chemoresistance. Yamanaka factors [octamer-binding transcription factor 4 (OCT4), SRY (sex-determining region Y)-box 2 (SOX2), kruppel-like factor 4 (KLF4), and Myelocytomatosis (MYC); OSKM] are responsible for cancer cell stemness, chemoresistance, and recurrence.Area covered: We cover recent discoveries and investigate the role of OSKM in inducing pluripotency and stem cell-like properties in various cancers with special emphasis on liver cancer. We review Yamanaka factors' role in stemness and chemoresistance of liver cancer.Expert opinion: In CSCs, including liver CSCs, the deregulation of various signaling pathways is one of the major reasons for stemness and drug resistance and is primarily due to OSKM. OSKM are responsible for tumor heterogeneity which renders targeting drug useless after a certain period. These factors can be exploited to understand the underlying mechanism of cancer stemness and resistance to chemotherapeutic drugs.

The emerging function and clinical significance of circRNAs in Thyroid Cancer and Autoimmune Thyroid Diseases

Thyroid cancer (TC) is one of the most common malignant tumors, with high morbidity and mortality rates worldwide. The incidence of TC, especially that of papillary thyroid carcinoma (PTC); has increased rapidly in recent decades. Autoimmune thyroid disease (AITD) is closely related to TC and has an estimated prevalence of 5%. Thus, it is becoming increasingly important to identify potential diagnostic biomarkers and therapeutic targets for TC and AITD. Circular RNAs (circRNAs) are a class of non-coding RNAs with covalently bonded circular structures that lack 5'-3' polarity and polyadenylated tails. Several circRNAs play crucial roles in the development of various diseases, including TC and AITD, and could be important new biomarkers and/or targets for the diagnosis and therapy of such disorders. Although there are four subtypes of TC, research on circRNA has largely focused on its connection to PTC. Therefore, this review mainly summarizes the relationships between circRNAs and PTC and AITD, including the molecular mechanisms underlying these relationships. In particular, the functions of “miRNA sponges” and their interactions with proteins and RNA are discussed. The possible targeting of circRNAs for the prevention, diagnosis, and treatment of TC and AITD is also described. CircRNAs could be potential biomarkers of TC and AITD, although validation will be required before they can be implemented in clinical practice.

Circular RNAs in drug resistant tumors

Chemotherapy is an effective method to treat patients with advanced malignant tumors. However, tumor cells can develop resistance to multiple drugs during the therapy process, leading to treatment failure. Circular RNAs (circRNAs) are a new class of regulatory RNAs that can regulate endogenous gene expression. Previous studies revealed the diagnostic and prognostic value of circRNAs in malignant cancer and other diseases, but few reports have examined their association with clinical drug resistance. In this review, we summarize the up-to-date information regarding the role of circRNAs in the resistance of tumors to chemotherapy and discuss specific regulatory mechanisms. This analysis is expected to provide direction for the prevention and management of drug resistance in tumors.

In Silico Integration Approach Reveals Key MicroRNAs and Their Target Genes in Follicular Thyroid Carcinoma

To better understand the molecular mechanism for the pathogenesis of follicular thyroid carcinoma (FTC), this study aimed at identifying key miRNAs and their target genes associated with FTC, as well as analyzing their interactions. Based on the gene microarray data GSE82208 and microRNA dataset GSE62054, the differentially expressed genes (DEGs) and microRNAs (DEMs) were obtained using R and SAM software. The common DEMs from R and SAM were fed to three different bioinformatic tools, TargetScan, miRDB, and miRTarBase, respectively, to predict their biological targets. With DEGs intersected with target genes of DEMs, the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed through the DAVID database. Then a protein-protein interaction (PPI) network was constructed by STRING. Finally, the module analysis for PPI network was performed by MCODE and BiNGO. A total of nine DEMs were identified, and their function might work through regulating hub genes in the PPI network especially KIT and EGFR. KEGG analysis showed that intersection genes were enriched in the PI3K-Akt signaling pathway and microRNAs in cancer. In conclusion, the study of miRNA-mRNA network would offer molecular support for differential diagnosis between malignant FTC and benign FTA, providing new insights into the potential targets for follicular thyroid carcinoma diagnosis and treatment.

Circular RNA EIF6 (Hsa_circ_0060060) sponges miR-144-3p to promote the cisplatin-resistance of human thyroid carcinoma cells by autophagy regulation

Anaplastic thyroid carcinoma (ATC) responds for the majority of death of thyroid carcinoma and often causes chemotherapy resistance. We investigated the influence of circEIF6 (Hsa_circ_0060060) on the cisplatin-sensitivity in papillary thyroid carcinoma (PTC) and ATC cells, and explored its regulation to downstream molecules miR-144-3p and Transforming Growth Factor α (TGF-α). Differentially expressed circRNAs in PTC were analyzed using the GSE93522 data downloaded. Expressions of circEIF6, miR-144-3p, TGF-α, autophagy-related proteins and apoptosis-related proteins were determined using qRT-PCR or western blot. RNA pull-down assay and dual luciferase report assay were applied to reveal the target relationships. Autophagy marker LC3 and cell proliferation marker ki67 were evaluated by immunofluorescence and immunohistochemistry. Cell viability was evaluated with MTT assay and cell apoptosis was assessed by flow cytometric analysis. CircEIF6, could promote autophagy induced by cisplatin, thus inhibiting cell apoptosis and enhancing the resistance of PTC and ATC cells to cisplatin. Has-miR-144-3p was the target of circEIF6 and was regulated by circEIF6. Besides, circEIF6 promoted autophagy by regulating miR-144-3p/TGF-α axis, enhancing the cisplatin-resistance in PTC and ATC cells. CircEIF6 promoted tumor growth by regulating miR-144-3p/TGF-α and circEIF6 knock-down enhanced cisplatin sensitivity in vivo. CircEIF6 could provide a target for therapy of cisplatin-resistance in thyroid carcinoma.

FBXO17 promotes cell proliferation through activation of Akt in lung adenocarcinoma cells

BACKGROUND

The ubiquitin-proteasome pathway, mediated in part, by ubiquitin E3 ligases, is critical in regulating cellular processes such as cell proliferation, apoptosis, and migration. FBXO17 was recently identified as an F-box protein that targets glycogen synthase kinase-3β to the E3 ubiquitin ligase protein complex for polyubiquitination and proteasomal degradation. Here, we identified that in several lung adenocarcinoma cell lines, FBXO17 cellular protein was detected at relatively high levels, as was expression in a subset of lung cancers. Hence, we investigated the effects of FBXO17 on cell proliferation.

METHODS

Single cell RNA sequencing analysis was performed on a resection of a non-small cell lung carcinoma tumor to examine FBXO17 expression. Multiple lung cancer cell lines were immunoblotted, and The Cancer Genome Atlas was analyzed to determine if FBXO17 expression was amplified in a subset of lung cancers. A549 cells were transfected with empty vector or FBXO17-V5 plasmid and immunoblotted for Akt pathway mediators including PDK1, ERK1/2, ribosomal protein S6, and CREB. Cell proliferation and viability were analyzed by trypan blue exclusion, BrdU incorporation and an MTS-based fluorometric assay. Studies were also performed after transfecting with sifbxo17. Samples were used in an RNA microarray analysis to evaluate pathways affected by reduced FBXO17 gene expression.

RESULTS

We observed that overexpression of FBXO17 increased A549 cell proliferation coupled with Akt activation. Ectopically expressed FBXO17 also increased ERK1/2 kinase activation and increased phosphorylation of RPS6, a downstream target of mTOR. We also observed an increased number of cells in S-phase and increased metabolic activity of lung epithelial cells expressing FBXO17. FBXO17 knockdown reduced Akt Ser 473 phosphorylation approaching statistical significance with no effect on Thr 308. However, ERK1/2 phosphorylation, cellular metabolic activity, and overall cell numbers were reduced. When we analyzed RNA profiles of A549 cells with reduced FBXO17 expression, we observed downregulation of several genes associated with cell proliferation and metabolism.

CONCLUSIONS

These data support a role for FBXO17 abundance, when left unchecked, in regulating cell proliferation and survival through modulation of Akt and ERK kinase activation. The data raise a potential role for the F-box subunit in modulating tumorigenesis.

Inhibiting 6-phosphogluconate dehydrogenase reverses doxorubicin resistance in anaplastic thyroid cancer via inhibiting NADPH-dependent metabolic reprogramming

Anaplastic thyroid carcinoma (ATC) is the most aggressive type of thyroid malignancies and resistant to chemotherapy. Little is known on the underlying mechanisms of ATC resistance to chemotherapy. In our work, we identified that 6-phosphogluconate dehydrogenase (6PGD) is critically involved in the development of ATC resistance to doxorubicin. We found that 6PGD mRNA, protein and enzyme activity levels are significantly upregulated in ATC cells during the prolonged exposure to doxorubicin in a time-dependent manner. 6PGD inhibition by genetic and pharmacological approaches significantly inhibits growth and survival of ATC cells that are highly resistant to doxorubicin. Consistently, 6PGD inhibition also sensitizes ATC cells to doxorubicin treatment. Of note, we observed the decreased level of NADPH, NADH and enzymatic activity of sirtuin-1 in response to 6PGD inhibition in doxorubicin-resistant ATC cells. Lactate level was also reduced by 6PGD inhibition. All these indicate that 6PGD inhibition disrupts metabolic reprogramming in doxorubicin-resistant ATC cells. Our work demonstrates 6PGD activation-mediated resistance in response to doxorubicin and provides an alternative therapeutic strategy to overcome resistance to chemotherapy for ATC treatment. Our findings also highlight the importance of metabolic reprogramming in ATC chemoresistance.