Inhibition of HAX-1 by miR-125a reverses cisplatin resistance in laryngeal cancer stem cells

Heterogeneous graph inference with range constrainted L2,1-collaborative matrix factorization for small molecule-miRNA association prediction

MicroRNAs (miRNAs) play a vital role in regulating gene expression and various biological processes. As a result, they have been identified as effective targets for small molecule (SM) drugs in disease treatment. Heterogeneous graph inference stands as a classical approach for predicting SM-miRNA associations, showcasing commendable convergence accuracy and speed. However, most existing methods do not adequately address the inherent sparsity in SM-miRNA association networks, and imprecise SM/miRNA similarity metrics reduce the accuracy of predicting SM-miRNA associations. In this research, we proposed a heterogeneous graph inference with range constrained L2,1-collaborative matrix factorization (HGIRCLMF) method to predict potential SM-miRNA associations. First, we computed the multi-source similarities of SM/miRNA and integrated these similarity information into a comprehensive SM/miRNA similarity. This step improved the accuracy of SM and miRNA similarity, ensuring reliability for the subsequent inference of the heterogeneity map. Second, we used a range constrained L2,1-collaborative matrix factorization (RCLMF) model to pre-populate the SM-miRNA association matrix with missing values. In this step, we developed a novel matrix decomposition method that enhances the robustness and formative nature of SM-miRNA edges between SM networks and miRNA networks. Next, we built a well-established SM-miRNA heterogeneous network utilizing the processed biological information. Finally, HGIRCLMF used this network data to infer unknown association pair scores. We implemented four cross-validation experiments on two distinct datasets, and HGIRCLMF acquired the highest areas under the curve, surpassing six state-of-the-art computational approaches. Furthermore, we performed three case studies to validate the predictive power of our method in practical application.

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.

MicroRNAs as the pivotal regulators of cisplatin resistance in head and neck cancers

Although, there is a high rate of good prognosis in early stage head and neck tumors, about half of these tumors are detected in advanced stages with poor prognosis. A combination of chemotherapy, radiotherapy, and surgery is the treatment option in head and neck cancer (HNC) patients. Although, cisplatin (CDDP) as the first-line drug has a significant role in the treatment of HNC patients, CDDP resistance can be observed in a large number of these patients. Therefore, identification of the molecular mechanisms involved in CDDP resistance can help to reduce the side effects and also provides a better therapeutic management. MicroRNAs (miRNAs) as the post-transcriptional regulators play an important role in drug resistance. Therefore, in the present review we investigated the role of miRNAs in CDDP response of head and neck tumors. It has been reported that the miRNAs exerted their roles in CDDP response by regulation of signaling pathways such as WNT, NOTCH, PI3K/AKT, TGF-β, and NF-kB as well as apoptosis, autophagy, and EMT process. The present review paves the way to suggest a non-invasive miRNA based panel marker for the prediction of CDDP response among HNC patients. Therefore, such diagnostic miRNA based panel marker reduces the CDDP side effects and improves the clinical outcomes of these patients following an efficient therapeutic management.

The role of miRNAs in laryngeal cancer pathogenesis and therapeutic resistance - A focus on signaling pathways interplay

Laryngeal cancer (LC)is the malignancy of the larynx (voice box). The majority of LC are squamous cell carcinomas. Many risk factors were reported to be associated with LC as tobacco use, obesity, alcohol intake, human papillomavirus (HPV) infection, and asbestos exposure. Besides, epigenetics as non-coding nucleic acids also have a great role in LC. miRNAs are short nucleic acid molecules that can modulate multiple cellular processes by regulating the expression of their genes. Therefore, LC progression, apoptosis evasions, initiation, EMT, and angiogenesis are associated with dysregulated miRNA expressions. miRNAs also could have some vital signaling pathways such as mTOR/P-gp, Wnt/-catenin signaling, JAK/STAT, KRAS, and EGF. Besides, miRNAs also have a role in the modulation of LC response to different therapeutic modalities. In this review, we have provided a comprehensive and updated overview highlighting the microRNAs biogenesis, general biological functions, regulatory mechanisms, and signaling dysfunction in LC carcinogenesis, in addition to their clinical potential for LC diagnosis, prognosis, and chemotherapeutics response implications.

miRNAs as potential game-changers in head and neck cancer: Future clinical and medicinal uses

Head and neck cancers (HNCs) are a group of heterogeneous tumors formed most frequently from epithelial cells of the larynx, lips, oropharynx, nasopharynx, and mouth. Numerous epigenetic components, including miRNAs, have been demonstrated to have an impact on HNCs characteristics like progression, angiogenesis, initiation, and resistance to therapeutic interventions. The miRNAs may control the production of numerous genes linked to HNCs pathogenesis. The roles that miRNAs play in angiogenesis, invasion, metastasis, cell cycle, proliferation, and apoptosis are responsible for this impact. The miRNAs also have an impact on crucial HNCs-related mechanistic networks like the WNT/β-catenin signaling, PTEN/Akt/mTOR pathway, TGFβ, and KRAS mutations. miRNAs may affect how the HNCs respond to treatments like radiation and chemotherapy in addition to pathophysiology. This review aims to demonstrate the relationship between miRNAs and HNCs with a particular emphasis on how miRNAs impact HNCs signaling networks.

Diagnostic and Prognostic Value of microRNAs in Patients with Laryngeal Cancer: A Systematic Review

Laryngeal squamous cell cancer (LSCC) is one of the most common malignant tumors of the head and neck region, with a poor survival rate (5-year overall survival 50-80%) as a consequence of an advanced-stage diagnosis and high recurrence rate. Tobacco smoking and alcohol abuse are the main risk factors of LSCC development. An early diagnosis of LSCC, a prompt detection of recurrence and a more precise monitoring of the efficacy of different treatment modalities are currently needed to reduce the mortality. Therefore, the identification of effective diagnostic and prognostic biomarkers for LSCC is crucial to guide disease management and improve clinical outcomes. In the past years, a dysregulated expression of small non-coding RNAs, including microRNAs (miRNAs), has been reported in many human cancers, including LSCC, and many miRNAs have been explored for their diagnostic and prognostic potential and proposed as biomarkers. We searched electronic databases for original papers that were focused on miRNAs and LSCC, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. According to the outcome, 566 articles were initially screened, of which 177 studies were selected and included in the analysis. In this systematic review, we provide an overview of the current literature on the function and the potential diagnostic and prognostic role of tissue and circulating miRNAs in LSCC.

Oxaliplatin Induces Immunogenic Cell Death in Human and Murine Laryngeal Cancer

Background

Cisplatin resistance is observed in patients with laryngeal cancer. The present study was designed to explore the efficacy of oxaliplatin on laryngeal cancer and elucidate the underlying mechanisms.

Methods

Cell viability was determined by using MTT assays. Cell apoptosis was determined by using annexin V and propidium iodide (PI) staining. Flow cytometry and immunofluorescence were applied to determine the levels of calreticulin (CALR) and DiD (1,1-dioctadecyl-3,3,3,3-tetramethylindodicarbocyanine). Flow cytometry was applied to analyze the levels of CD83, CD86, IFN-γ-producing CD8⁺ T cells, and CD4⁺CD25⁺FoxP3⁺ Tregs. The levels of adenosine triphosphate (ATP) were determined by using a chemiluminescent ATP kit and cytokines were determined by using specific enzyme-linked immunosorbent assays (ELISAs). The levels of HMGB1 were determined by using Western blot and ELISA, respectively. The xenograft animal model was constructed to evaluate the antitumor effects of oxaliplatin.

Results

Oxaliplatin inhibited cell growth, promoted cell apoptosis, and induced the levels of CALR, ATP, and high mobility group box protein 1 (HMGB1) in Hep-2 cells. Oxaliplatin-treated Hep-2 cells increased the intensity of DiD and the levels of CD83 and CD86 in dendritic cells (DCs), as well as induced the supernatant IL-6 and TNF-α. Oxaliplatin-treated primary laryngeal cancer cell-pulsed DCs increased the IFN-γ-producing CD8⁺ T cells and suppressed CD4⁺CD25⁺FoxP3⁺ Tregs. In vivo data showed that oxaliplatin suppressed tumor growth and increased the populations of CD86⁺CD80⁺ and CD8⁺CD45⁺ cells in the tumor tissues.

Conclusion

Treatment with oxaliplatin inhibited laryngeal cancer cells by inducing immunogenic cell death.

NLR, PLR, LMR and MWR as diagnostic and prognostic markers for laryngeal carcinoma

OBJECTIVE

To evaluate whether neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte to monocyte ratio (LMR) and monocyte-to-white blood cell ratio (MWR) can be used as diagnostic and prognostic markers for laryngeal carcinoma (LC).

METHODS

In this retrospective study, 50 patients with LC treated in the Department of Otolaryngology, Head and Neck Surgery of Beijing Tongren Hospital from August 2014 to August 2015 were enrolled in research group. In addition, 40 healthy volunteers from the same period were selected as control group. The counts of white blood cells, neutrophils, lymphocytes, monocytes and platelets in the peripheral blood of participants were measured with a blood counting instrument (Sysmex XE-2100, Sysmex Corporation, Japan), and the NLR, PLR, LMR and MWR were calculated. After that, the survival rate of patients was observed through a 5-year follow-up. The prognostic value of the above four indexes and their combination was discussed in patients with different clinical characteristics.

RESULTS

Compared with the control group, the NLR, PLR and MWR were higher and the LMR was lower in the research group. In terms of survival, patients with higher NLR, PLR and MWR and lower LMR showed a higher 5-year mortality than those with lower NLR, PLR and MWR and higher LMR, indicating that NLR, PLR and MWR were higher and LMR was lower in the survival group than in the death group. Subsequent analysis identified that NLR, PLR, LMR and MWR were closely correlated with age, alcohol drinking, smoking, clinical staging and T-staging. Clinical staging, T-staging, NLR, PLR, LMR, and MWR were confirmed as influencing factors for LC.

CONCLUSIONS

NLR, PLR, LMR, and MWR can be used as diagnostic and prognostic markers for LC and their combination has a superior diagnostic performance.

Overview on Molecular Biomarkers for Laryngeal Cancer: Looking for New Answers to an Old Problem

Laryngeal squamous cell cancer (LSCC) accounts for almost 25-30% of all head and neck squamous cell cancers and is clustered according to the affected districts, as this determines distinct tendency to recur and metastasize. A major role for numerous genetic alterations in driving the onset and progression of this neoplasm is emerging. However, major efforts are still required for the identification of molecular markers useful for both early diagnosis and prognostic definition of LSCC that is still characterized by significant morbidity and mortality. Non-coding RNAs appear the most promising as they circulate in all the biological fluids allowing liquid biopsy determination, as well as due to their quick and characteristic modulation useful for non-invasive detection and monitoring of cancer. Other critical aspects are related to recent progress in circulating tumor cells and DNA detection, in metastatic status and chemo-refractoriness prediction, and in the functional interaction of LSCC with chronic inflammation and innate immunity. We review all these aspects taking into account the progress of the technologies in the field of next generation sequencing.

[Research progress of microRNA in laryngeal squamous cell carcinoma]

Laryngeal carcinoma is one of the most common malignant tumors in the area of head and neck, and the main pathological type is laryngeal squamous cell carcinoma. Due to the fact that the disease usually have no overt clinical symptoms at the early stage and easy to relapse, it has a poor prognosis and low five-year survival rate. microRNA is a class of endogenous, non-coding RNA with a length of 19-25 nucleotides. microRNAs, mainly regulate the expression of target genes at the post-transcriptional level after complementing and pairing with the 3'-UTR area of the target gene. Studies have shown that the abnormal expression of microRNA is closely related to the occurrence, development, metastasis and prognosis of various cancers including laryngeal carcinoma. In this article, the research progress of microRNA in laryngeal squamous cell carcinoma is reviewed.

Exosomal microRNA-125a-3p from human adipose-derived mesenchymal stem cells promotes angiogenesis of wound healing through inhibiting PTEN

Angiogenesis plays a key in the process of tissue repair and wound healing. Human adipose-derived mesenchymal stem cells (HADSCs) have been found to act a promotion role during angiogenesis. Moreover, miR-125a-3p in HADSCs could promote the angiogenesis of HUVECs, but their specific mechanism in wound healing needs further study. Western blotting and qRT-PCR were used for detecting the protein and mRNA level, respectively. Exosomes were isolated successfully, and transmission electron microscope was used to identify exosomes. Angiogenesis, cell migration, and proliferation were detected with tube formation, wound healing, and MTT assays. The interactions of miR-125a-3p and PTEN were validated using dual-luciferase reporter assay. Animal model was used to evaluate the effect of miR-125a-3p on wound healing. HADSCs-exosome remarkably promoted the viability, migration, and angiogenesis of HUVECs. Knockdown of miR-125a-3p in HADSCs could inhibit the effect of HADSCs-exosome, while overexpression of miR-125a-3p could further promote the effect of HADSCs-exosome on HUVECs. MiR-125a-3p from HADSCs-exosome inhibited the expression of PTEN in HUVECs. Knockdown of PTEN promoted the viability, migration, and angiogenesis of HUVECs and reversed the effect of miR-125a-3p knockdown on HUVECs. Finally, miR-125a-3p from HADSCs-exosome could promote wound healing and angiogenesis in mice by inhibiting PTEN in mice wound granulation tissues. MiR-125a-3p from the HADSCs-exosome promoted the wound healing and angiogenesis, and these effects were achieved through regulating PTEN. This study may provide a new thought for the treatment and prevention of tissue repair.

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

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

The Role of the Hematopoietic Cell-Specific Protein 1-Associated Protein X-1 in Human Papillomavirus 16 E2-Induced Human Cervical Squamous Carcinoma Cell Apoptosis via a Mitochondria-Dependent Pathway

OBJECTIVES

Human papillomavirus 16 (HPV 16) E2 is a transcriptional regulator that plays a key role in regulating a variety of biological responses. Hematopoietic cell-specific protein 1-related protein X-1 (HAX-1) is a mitochondrial membrane protein, and the HAX-1 gene is involved in the occurrence, growth, invasion, and metastasis of various human malignant tumors. The purpose of this study was to investigate the relationships among HPV 16 E2, the role of HAX-1 gene, and the underlying intracellular apoptotic mechanism of human cervical squamous carcinoma cells (C33a and SiHa).

METHODS

In this study, HAX-1 expression was examined using real-time polymerase chain reaction, Western blot, and immunohistochemical staining analysis. Apoptosis of cells was assessed by flow cytometry. The mitochondrial function was assessed by the mitochondrial copy number, reactive oxygen species (ROS) generation, the mitochondrial membrane potential (ΔΨm), and mitochondrial morphology.

RESULTS

Our study demonstrated that the expression of the HAX-1 gene was significantly increased in human cervical carcinoma tissues relative to noncancerous cervix tissues. HPV 16 E2 inhibited HAX-1 protein expression. Overexpression of HAX-1 increased the mitochondrial copy number, decreased the production of ROS, and maintained the integrity of the mitochondrial membrane and morphology. So, enhanced expression of the HAX-1 gene could abrogate the HPV 16 E2-induced cell apoptosis.

CONCLUSION

Therefore, these data support a mechanism that HAX-1 plays a crucial role in HPV 16 E2-induced human cervical squamous carcinoma cell apoptosis in a mitochondrial-dependent manner.

Mitochondrial microRNA (MitomiRs) in cancer and complex mitochondrial diseases: current status and future perspectives

Mitochondria are not only important for cellular bioenergetics but also lie at the heart of critical metabolic pathways. They can rapidly adjust themselves in response to changing conditions and the metabolic needs of the cell. Mitochondrial involvement as well as its dysfunction has been found to be associated with variety of pathological processes and diseases. mitomiRs are class of miRNA(s) that regulate mitochondrial gene expression and function. This review sheds light on the role of mitomiRs in regulating different biological processes-mitochondrial dynamics, oxidative stress, cell metabolism, chemoresistance, apoptosis,and their relevance in metabolic diseases, neurodegenerative disorders, and cancer. Insilico analysis of predicted targets of mitomiRs targeting energy metabolism identified several significantly altered pathways (needs in vivo validations) that may provide a new therapeutic approach for the treatment of human diseases. Last part of the review discusses about the clinical aspects of miRNA(s) and mitomiRs in Medicine.

Tumor microenvironment: an evil nexus promoting aggressive head and neck squamous cell carcinoma and avenue for targeted therapy

Head and neck squamous cell carcinoma (HNSCC) is a very aggressive disease with a poor prognosis for advanced-stage tumors. Recent clinical, genomic, and cellular studies have revealed the highly heterogeneous and immunosuppressive nature of HNSCC. Despite significant advances in multimodal therapeutic interventions, failure to cure and recurrence are common and account for most deaths. It is becoming increasingly apparent that tumor microenvironment (TME) plays a critical role in HNSCC tumorigenesis, promotes the evolution of aggressive tumors and resistance to therapy, and thereby adversely affects the prognosis. A complete understanding of the TME factors, together with the highly complex tumor-stromal interactions, can lead to new therapeutic interventions in HNSCC. Interestingly, different molecular and immune landscapes between HPV^+ve and HPV^-ve (human papillomavirus) HNSCC tumors offer new opportunities for developing individualized, targeted chemoimmunotherapy (CIT) regimen. This review highlights the current understanding of the complexity between HPV^+ve and HPV^-ve HNSCC TME and various tumor-stromal cross-talk modulating processes, including epithelial-mesenchymal transition (EMT), anoikis resistance, angiogenesis, immune surveillance, metastatic niche, therapeutic resistance, and development of an aggressive tumor phenotype. Furthermore, we summarize the recent developments and the rationale behind CIT strategies and their clinical applications in HPV^+ve and HPV^-ve HNSCC.

LncRNAs and miRNAs participate in determination of sensitivity of cancer cells to cisplatin

Cisplatin is an extensively used chemotherapeutic substance for various types of human malignancies including sarcomas, carcinomas and lymphomas. Yet, the vast application of this drug is hampered by the emergence of chemoresistance in some treated patients. Several mechanisms such as degradation of the membrane transporters by cisplatin have been implicated in the pathogenesis of this event. Recent researches have also indicated the role of long non-coding RNAs (lncRNAs) as well as micoRNAs (miRNAs) in the emergence of resistance to cisplatin in several cancer types. For instance, up-regulation of miR-21 has been associated with resistance to this agent in ovarian cancer, oral squamous cell cancer, gastric malignancy and non-small cell lung cancer (NSCLC). On the other hand, down-regulation of miR-218 has been implicated in emergence of chemoresistance in breast cancer and esophageal squamous cell carcinoma. MALAT1 is implicated in the chemoresistance of bladder cancer cells, NSCLC, gastric cancer and cervical cancer. Most notably, the expression profile of resistance-associated miRNAs and lncRNAs can predict overall survival of cancer patients. Mechanistic assays have revealed that interference with expression of some miRNAs and lncRNAs can reverse the resistance phenotype in cancer cells. In this paper, we review the scientific writings on the role of lncRNAs and miRNAs in the evolution of chemoresistance to cisplatin in cancer cells.

Revisiting cancer hallmarks: insights from the interplay between oxidative stress and non-coding RNAs

Cancer is one of the most common disease worldwide, with complex changes and certain traits which have been described as “The Hallmarks of Cancer.” Despite increasing studies on in-depth investigation of these hallmarks, the molecular mechanisms associated with tumorigenesis have still not yet been fully defined. Recently, accumulating evidence supports the observation that microRNAs and long noncoding RNAs (lncRNAs), two main classes of noncoding RNAs (ncRNAs), regulate most cancer hallmarks through their binding with DNA, RNA or proteins, or encoding small peptides. Reactive oxygen species (ROS), the byproducts generated during metabolic processes, are known to regulate every step of tumorigenesis by acting as second messengers in cancer cells. The disturbance in ROS homeostasis leads to a specific pathological state termed “oxidative stress”, which plays essential roles in regulation of cancer progression. In addition, the interplay between oxidative stress and ncRNAs is found to regulate the expression of multiple genes and the activation of several signaling pathways involved in cancer hallmarks, revealing a potential mechanistic relationship involving ncRNAs, oxidative stress and cancer. In this review, we provide evidence that shows the essential role of ncRNAs and the interplay between oxidative stress and ncRNAs in regulating cancer hallmarks, which may expand our understanding of ncRNAs in the cancer development from the new perspective.

Knockdown of miR-183 Enhances the Cisplatin-Induced Apoptosis in Esophageal Cancer Through Increase of FOXO1 Expression

Background

As an important member of platinum-based chemotherapeutic drugs, cisplatin is effective and is commonly used in the treatment of esophageal cancer. However, repeated use of cisplatin usually causes severe side-effects on patients. Novel approaches should be explored to increase the sensitivity of cancer cells to cisplatin.

Methods

The expression level of miR-183 in esophageal cancer tissues and cell lines was measured by quantitative reverse transcriptase real-time PCR (qRT-PCR). The sensitivity of EC cell lines to cisplatin was evaluated by CCK-8 assay and flow cytometry. Luciferase reporter assay was used to confirm the association between miR-183 and FOXO1. The apoptosis pathway of EC cells was tested by Western blot assay.

Results

The expression level of miR-183 was increased in esophageal cancer patients' tumor tissues and esophageal cancer cell lines. However, knockdown of miR-183 was found to enhance the effect of cisplatin on inducing the apoptotic cell death of esophageal cancer cells. In the mechanism research, we proved that FOXO1 was the target of miR-183 in esophageal cancer cells. Inhibition of miR-183 increased the expression of FOXO1 to promote the expression of Bim and Noxa. As Bim and Noxa acted as key pro-apoptotic proteins in mitochondrial apoptosis, inhibition of miR-183 enhanced the cisplatin-induced apoptosis pathway in esophageal cancer.

Conclusion

Knockdown of miR-183 enhanced the cisplatin-induced apoptosis in esophageal cancer through an increase of FOXO1 expression.

miR-125a-5p inhibits glycolysis by targeting hexokinase-II to improve pulmonary arterial hypertension

Purpose: The aim of this study was to investigate the effect of microRNAs on the proliferation of pulmonary arterial smooth muscle cells (PASMCs) as a result of targeting hexokinase-II (HK-II) and its mechanism of action.

Results: Differences in metabolic patterns were found between the normal group and monocrotaline-induced pulmonary arterial hypertension (MCT-PH) group. miR-125a-5p decreased glycolysis levels of monocrotaline (MCT)-induced PASMCs by targeting HK-II and inhibiting its proliferation. In vivo experiments found that miR-125a-5p agomir upregulated HK-II expression in the MCT-PH. Right ventricular hypertrophy was reversed and cardiac function improved as a result of decreased mean pulmonary artery pressure (mPAP).

Conclusion: In vitro and in vivo experiments both confirmed that miR-125a-5p could inhibit cell glycolysis and PASMC proliferation to improve PAH by targeting HK-II.

Methods: HK-II overexpression was constructed, and differentially expressed microRNAs were screened for using microarrays. Serum metabolites were detected using Nuclear Magnetic Resonance (NMR). Through screening for characteristic metabolites in rat body fluids and by analyzing biological functions, disordered metabolic pathways were identified. Activity of the miR-125a-5p target HK-II was measured using a luciferase reporter assay. Expression of downstream molecules was measured by RT–qPCR and/or western blot. Glucose consumption and lactic acid production were analyzed and used as a reflection of glycolysis.

Non-coding RNAs in drug resistance of head and neck cancers: A review

Head and neck cancer (HNC), which includes epithelial malignancies of the upper aerodigestive tract (oral cavity, oropharynx, pharynx, hypopharynx, larynx, and thyroid), are slowly but consistently increasing, while the overall survival rate remains unsatisfactory. Because of the multifunctional anatomical intricacies of the head and neck, disease progression and therapy-related side effects often severely affect the patient's appearance and self-image, as well as their ability to breathe, speak, and swallow. Patients with HNC require a multidisciplinary approach involving surgery, radiation therapy, and chemotherapeutics. Chemotherapy is an important part of the comprehensive treatment of tumors, especially advanced HNC, but drug resistance is the main cause of poor clinical efficacy. The most important determinant of this phenomenon is still largely unknown. Recent studies have shown that non-coding RNAs have a crucial role in HNC drug resistance. In addition, they can serve as biomarkers in the diagnosis, treatment, and prognosis of HNCs. In this review, we summarize the relationship between non-coding RNAs and drug resistance of HNC, and discuss their potential clinical application in overcoming HNC chemoresistance.

Frataxin deficiency in Friedreich's ataxia is associated with reduced levels of HAX-1, a regulator of cardiomyocyte death and survival

Frataxin deficiency, responsible for Friedreich's ataxia (FRDA), is crucial for cell survival since it critically affects viability of neurons, pancreatic beta cells and cardiomyocytes. In FRDA, the heart is frequently affected with typical manifestation of hypertrophic cardiomyopathy, which can progress to heart failure and cause premature death. A microarray analysis performed on FRDA patient's lymphoblastoid cells stably reconstituted with frataxin, indicated HS-1-associated protein X-1 (HAX-1) as the most significantly upregulated transcript (FC = +2, P < 0.0006). quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) and western blot analysis performed on (I) HEK293 stably transfected with empty vector compared to wild-type frataxin and (II) lymphoblasts from FRDA patients show that low frataxin mRNA and protein expression correspond to reduced levels of HAX-1. Frataxin overexpression and silencing were also performed in the AC16 human cardiomyocyte cell line. HAX-1 protein levels are indeed regulated through frataxin modulation. Moreover, correlation between frataxin and HAX-1 was further evaluated in peripheral blood mononuclear cells (PBMCs) from FRDA patients and from non-related healthy controls. A regression model for frataxin which included HAX-1, group membership and group* HAX-1 interaction revealed that frataxin and HAX-1 are associated both at mRNA and protein levels. Additionally, a linked expression of FXN, HAX-1 and antioxidant defence proteins MnSOD and Nrf2 was observed both in PBMCs and AC16 cardiomyocytes. Our results suggest that HAX-1 could be considered as a potential biomarker of cardiac disease in FRDA and the evaluation of its expression might provide insights into its pathogenesis as well as improving risk stratification strategies.

Inhibition of TRIM32 Induced by miR-519d Increases the Sensitivity of Colorectal Cancer Cells to Cisplatin

BACKGROUND

Colorectal cancer is a leading cause of cancer-related death in the world. Despite cisplatin is a commonly used chemotherapeutic drug for the colorectal cancer treatment, resistance of cancer cells to cisplatin restricts its clinical efficacy. It is important to explore the potential mechanisms and take strategies to sensitize colorectal cancer cells to cisplatin treatment.

METHODS

Differences of TRIM32 and miR-519d expression between colorectal cancer cells and human normal colon epithelial cells were evaluated by qRT-PCR and Western blot assays. Cytotoxicity of cisplatin against colorectal cancer cells was tested by CCK-8 assay. Generation of reactive oxygen species (ROS), mitochondrial membrane potential and apoptosis was measured by flow cytometry. Dual-luciferase reporter assay was used to validate the association between miR-519d and TRIM32.

RESULTS

Significant increase of TRIM32 expression in colorectal cancer tissues and cell lines was observed. TRIM32 negatively regulated the cisplatin sensitivity in colorectal cancer cells. Mechanically, overexpression of TRIM32 was induced by decrease of miR-519d. Exogenous miR-519d can inhibit the expression of TRIM32 and thus promoted the cisplatin-induced apoptosis through the mitochondrial pathway.

CONCLUSION

Overexpression of TRIM32 was induced by the absence of miR-519d in colorectal cancer. MiR-519d can be used as a sensitizer during the cisplatin-based chemotherapy of colorectal cancer.

MicroRNA-125 in immunity and cancer

MicroRNAs (miRNAs) are small non-coding RNAs that play a wide variety of critical roles in different biological processes by post-transcriptionally regulating gene expression. They access diverse regulatory pathways during various stages of cellular differentiation, growth, and apoptosis, and can contribute to both normal and diseased functions. One important family of miRNAs involved in these functions is the miR-125 family (miR-125a and miR-125b). Investigations have been made to increasingly uncover the mechanisms by which the miR-125 family regulates normal homeostasis and growth in a variety of cell types including immune cells, and how dysregulation of miR-125a and miR-125b can lead to disease pathogenesis and tumorigenesis. In this review, we summarize what is currently known about miR-125a and miR-125b, mainly focusing on their roles in immune cell development and function as well as tumor suppression and promotion.

The Role of MicroRNAs in Recurrence and Metastasis of Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) affects 650,000 people worldwide and has a dismal 50% 5-year survival rate. Recurrence and metastasis are believed the two most important factors causing this high mortality. Understanding the biological process and the underlying mechanisms of recurrence and metastasis is critical to develop novel and effective treatment, which is expected to improve patients' survival of HNSCC. MicroRNAs are small, non-coding nucleotides that regulate gene expression at the transcriptional and post-transcriptional level. Oncogenic and tumor-suppressive microRNAs have shown to regulate nearly every step of recurrence and metastasis, ranging from migration and invasion, epithelial-mesenchymal transition (EMT), anoikis, to gain of cancer stem cell property. This review encompasses an overview of microRNAs involved in these processes. The recent advances of utilizing microRNA as biomarkers and targets for treatment, particularly on controlling recurrence and metastasis are also reviewed.

miR-374a Inhibitor Enhances Etoposide-Induced Cytotoxicity Against Glioma Cells Through Upregulation of FOXO1

Glioma is a commonly diagnosed brain tumor that shows high mortality rate. Despite the great advancement of cancer therapy in recent years, chemotherapy is still an important approach for treatment of glioma. However, long-term chemotherapy usually causes serious side effects or complications. It is desirable to take strategies to enhance the efficacy of current chemotherapy. In the present study, we observed obvious upregulation of miR-374a in glioma cells. More importantly, we found that knockdown of miR-374a was able to enhance the etoposide-induced cytotoxicity against glioma cells. Mechanically, we demonstrated that FOXO1 was the target of miR-374a in glioma. Treatment with miR-374a inhibitor induced overexpression of FOXO1, and thus promoted the expression of Bim and Noxa. Since Bim and Noxa act as key proapoptotic proteins in mitochondrial apoptosis, miR-374a inhibitor was able to enhance the etoposide-induced apoptosis pathway in glioma.

Effect of lncRNA ANRIL knockdown on proliferation and cisplatin chemoresistance of osteosarcoma cells in vitro

Chemoresistance is a major obstacle in treating cancer, including osteosarcoma. LncRNA ANRIL (ANRIL) is involved in the growth and metastasis of osteosarcoma cells, however, its role in chemoresistance remains unclear. In this study, ANRIL shRNA was used to knock down its endogenous expression in U2-OS and Saos-2 osteosarcoma cell lines. Our data showed that ANRIL-silenced cells were more sensitive to cisplatin: apoptotic ratio was increased and cleaved caspase-3 level was upregulated. Furthermore, the expression level of miR-125a-5p, a microRNA that can bind to ANRIL, was elevated in ANRIL-silenced cells. MiR-125a-5p inhibitor attenuated ANRIL knockdown-induced chemosensitivity to cisplatin. In addition, ANRIL knockdown resulted in a reduction in STAT3, a target of miR-125a-5p, in osteosarcoma cells. Forced overexpression of STAT3 weakened the chemosensitivity of ANRIL-silenced cells to cisplatin. In conclusion, our study demonstrates that ANRIL knockdown sensitizes osteosarcoma cells to cisplatin-induced cytotoxicity, suggesting ANRIL as a therapeutic target for osteosarcoma chemotherapy.

MicroRNA-mediated redox regulation modulates therapy resistance in cancer cells: clinical perspectives

BACKGROUND

Chemotherapy and radiation therapy are the most common types of cancer therapy. The development of chemo/radio-resistance remains, however, a major obstacle. Altered redox balances are among of the main factors mediating therapy resistance. Therefore, redox regulatory strategies are urgently needed to overcome this problem. Recently, microRNAs have been found to act as major redox regulatory factors affecting chemo/radio-resistance. MicroRNAs play critical roles in regulating therapeutic resistance through the regulation of antioxidant enzymes, redox-sensitive signaling pathways, cancer stem cells, DNA repair mechanisms and autophagy.

CONCLUSIONS

Here, we summarize current knowledge on microRNA-mediated redox regulatory mechanisms underlying chemo/radio-resistance. This knowledge may form a basis for a better clinical management of cancer patients.

miR-125a/b inhibits tumor-associated macrophages mediated in cancer stem cells of hepatocellular carcinoma by targeting CD90

Cancer stem cells promote tumorigenesis and progression of hepatocellular carcinoma (HCC). Recently, emerging evidence indicates tumor-associated macrophages (TAMs) play an important role in tumor progression. However, TAMs often occurs with unknown mechanisms. As an important mediator in intercellular communications, exosomes secreted by host cells mediate the exchange of genetic materials and proteins, which involves tumor aggressiveness. The aim of the study was to investigate whether exosomes derived from TAMs mediate stem cell properties in HCC. TAMs were isolated from the tissues of HCC. microRNA (miRNA) expression profiles of TAMs were analyzed using miRNA microarray. In vitro cell coculture was further conducted to investigate the crosstalk between TAMs and tumor cells mediated by TAMs exosomes. In this study, we showed that TAMs exosomes promote HCC cell proliferation and stem cell properties. Using miRNA profiles assay, we identified significantly lower levels of miR-125a and miR-125b in exosomes and cell lysate isolated from TAMs. Functional studies revealed that the HCC cells were treated with TAM exosomes or transfected with miR-125a/b suppressed cell proliferation and stem cell properties by targeting CD90, a stem cell marker of HCC stem cells. The study indicated that miR-125a/b targeting CD90 played important roles in cancer stem cells of HCC.

Circular RNA hsa_circ_0052112 promotes cell migration and invasion by acting as sponge for miR-125a-5p in breast cancer

OBJECTIVES

Accumulating evidence has been reported that circular RNAs (circRNAs) are a class of relatively stable, non-coding RNAs, which are involved in the progression of many types of diseases. However, the mechanism of hsa_circ_0052112 in breast cancer cells is not entirely clear. Hsa_circ_0052112, generated from the ZNF83 gene, is selected by analyzing circRNA expression profiles of breast cancer cell by using microarray assay. In this study, we will show the role of hsa_circ_0052112 in regulating cell invasion and migration in breast cancer.

METHODS

The expression level of hsa_circ_0052112 in MCF-7 and MDA-MB-231 cells was detected by RT-qPCR; we performed transwell assay to evaluate breast cancer cells' migration and invasion; predicated circRNA/miRNAs interaction using the miRanda and RNAhybrid software; identified the relationship between hsa_circ_0052112 and miR-125a-5p by luciferase activity assay and show the localization of hsa_circ_0052112 by FISH assay and show the significance of ZNF83 in clinical prognosis by Kaplan-Meier survival analysis.

RESULTS

Hsa_circ_0052112 expression was significantly higher in MDA-MB-231 cells than that in MCF-7 cells. Overexpression of hsa_circ_0052112 promoted cell migration and invasion in breast cancer. Inversely, down-regulation of hsa_circ_0052112 suppressed breast cancer cells migration and invasion. Hsa_circ_0052112 was mostly located in cytoplasm. Hsa_circ_0052112 could directly sponge to miR-125a-5p; overexpression of miR-125a-5p significantly inhibited breast cancer cells migration and invasion. However, high or low expression of miR-125a-5p was not correlated with relapse free survival (RFS) by TCGA database validation, but high expression of ZNF83 was closely correlated with poor RFS by Kaplan-Meier plotter.

CONCLUSIONS

These data suggest that hsa_circ_0052112 may be a potent biomarker for breast cancer, and may provide a new perspective on treatment of breast cancer.

MiR-30a-5p confers cisplatin resistance by regulating IGF1R expression in melanoma cells

BACKGROUND

Melanoma is notoriously resistant to all current modalities of cancer therapies including chemotherapy. In recent years, microRNAs (miRNAs) have emerged as molecular regulators in the development and progression of melanoma. However, the relationship between microRNA and chemo-resistance of melanoma is little known. In present study, we aimed to investigate the miRNAs related to cisplatin-resistance in melanoma cells.

METHODS

After cisplatin (DDP) resistant melanoma cells (M8/DDP and SK-Mel-19/DDP) were established in-vitro, high-throughput screening of differentially expressed miRNAs between resistant cells and parental cells were performed.

RESULTS

It was found that a cancer-related miRNA, miR-30a-5p, was highly over-expressed in resistant cells. Transfection of miR-30a-5p mimic or inhibitor could alter the sensitivity of melanoma cells to cisplatin. Next, we showed that Insulin Like Growth Factor 1 Receptor (IGF1R) gene turned out to be a direct target of miR-30a-5p. Knockdown of IGF1R in melanoma cells could not only reduce the sensitivity to cisplatin but also lead to cell cycle arrest by regulating phosphorylation of Serine-Threonine Protein Kinase (P-AKT (Ser473)) and Tumor Protein P53 (P53).

CONCLUSION

Taken together, our study demonstrated that miR-30a-5p could influence chemo-resistance by targeting IGF1R gene in melanoma cells, which might provide a potential target for the therapy of chemo-resistant melanoma cells.

MiR-106b inhibitors sensitize TRAIL-induced apoptosis in hepatocellular carcinoma through increase of death receptor 4

TNF-related apoptosis-inducing ligand (TRAIL), which is a member of the TNF superfamily, can induce tumor cell apoptosis. However, multiple types of tumor, including hepatocellular carcinoma, show tolerance to TRAIL. Previous studies have demonstrated that tumor cells usually change their expression profile of microRNA (miRNA) to obtain the ability of tolerance to drugs. However, whether such change of miRNA on TRAIL sensitivity is seen in hepatocellular carcinoma still needs to be explored. In this study, we observed overexpression of miR-106b in both HCC patients’ tumor tissues and cell lines. Furthermore, we found that overexpression of miR-106b is associated with the sensitivity of TRAIL to HCC. Silencing of miR-106b with antisense oligonucleotide (anti-miR-106b) is proved to enhance the TRAIL-induced apoptosis and reduce the acquired drug resistance to TRAIL in HCC. Mechanically, we didn't observe the obvious change of pro-apoptotic proteins (Bax and Bid) and anti-apoptotic proteins (Bcl-2, Mcl-1 and Bcl-xl) after treatment of anti-miR-106b. However, we used the methods of bioinformatics, flow cytometry, cellular and molecular methods to prove that miR-106b directly targeted to death receptor 4 (DR4) 3′-UTR (3′-Untranslated Regions). MiR-106b inhibitors induced increase of DR4 expression and therefore enhancing TRAIL-mediated apoptosis in HCC. In summary, these results suggest the application of miR-106b inhibitors in HCC treatment. Combination with miR-106b inhibitors and TRAIL may be a novel clinical treatment method on HCC treatment in the future.

lncRNA-NKILA/NF-κB feedback loop modulates laryngeal cancer cell proliferation, invasion, and radioresistance

Laryngeal cancer is one of the most common head and neck malignant tumors and is commonly resistant to X‐ray‐based radiotherapy. NF‐κB interacting lncRNA (NKILA) has been reported to serve as a tumor suppressor in several cancers through combining with NF‐κB: IκB complex thereby inhibiting NF‐κB activation. Herein, we demonstrated a low NKILA expression in laryngeal cancer and its correlation with shorter overall survival in patients with laryngeal cancer. NKILA serves as a tumor suppressor in laryngeal cancer by suppressing laryngeal cancer cell viability and migration, whereas promoting cell apoptosis; NKILA knockdown reverses the cytotoxicity of X‐ray radiation on laryngeal cancer cells through combining with NF‐κB: IκB complex to inhibit IκB phosphorylation, inhibit p65 nuclear translocation, and finally inhibit NF‐κB activation. NF‐κB binds to the promoter region of NKILA to activate its transcriptional activity, upregulated NKILA then inhibits IκB phosphorylation and NF‐κB activation, thus forming a negative feedback loop to sensitize laryngeal cancer cell to X‐ray radiation. In conclusion, NKILA can serve as a promising agent of enhancing the cytotoxicity of X‐ray radiation on laryngeal cancer and addressing the radioresistance of laryngeal cancer.

MiR-519d impedes cisplatin-resistance in breast cancer stem cells by down-regulating the expression of MCL-1

Cancer stem cells are considered as the cell population which is responsible for chemoresistance and treatment failure in breast cancer patients. Therefore, it is urgent to explore the mechanism by which cancer stem cells survive under the treatment of chemotherapeutic drugs such as cisplatin. In this paper, we demonstrated significant decrease of miR-519d in breast cancer stem cells by quantitative RT-PCR analysis. Furthermore, we found the enforced expression of miR-519d in T-47D-cancer stem cells significantly increased their sensitivity to cisplatin through the apoptosis pathway. In addition, the gene of MCL-1, which is a member of pro-apoptotic Bcl-2 family, was found to be the target of miR-519d in T-47D-cancer stem cells. Our date demonstrated that enforced miR-519d expression enhanced the cisplatin-induced apoptosis through the MCL-1 dependent mitochondria pathway in breast cancer stem cells. Taken together, the present study suggests that miR-519d reduces chemoresistance in breast cancer stem cells, and understanding of miR-519d may be helpful for increasing the efficacy of chemotherapy.

miR-125a suppresses viability and glycolysis and induces apoptosis by targeting Hexokinase 2 in laryngeal squamous cell carcinoma

Background

miR-125a usually functions as a tumor suppressor in cancers. However, the role of miR-125a in laryngeal squamous cell carcinoma (LSCC) has not been determined.

Methods

qRT-PCR was applied to measure the expression of miR-125a and HK2 mRNA in LSCC tissues and cells. CCK-8 kit and flow cytometry analysis were performed to detect cell viability and apoptosis. Luciferase reporter assay and RNA immunoprecipitation (RIP) were conducted to confirm the relationship between miR-125a and HK2. Commercial test kits were used to determine the concentrations of glucose and l-lactate. Xenograft in mice was constructed to validate the function and mechanism of miR-125a in LSCC tumor growth.

Results

A negative correlation was found between miR-125a expression and the level of Hexokinase 2 (HK2) mRNA in LSCC tissues. Functional experiments found that miR-125a inhibited viability and glycolysis and induced apoptosis in LSCC cells. Similarly, HK2 downregulation led to viability and glycolysis inhibition and induction of apoptosis in LSCC cells in vitro. Moreover, miR-125a overexpression suppressed LSCC xenograft growth in vivo. Mechanically, HK2 was verified to be a target of miR-125a by luciferase reporter assays and RNA immunoprecipitation (RIP) assays. Furthermore, restored HK2 expression reversed miR-125a-mediated proliferation and glycolysis inhibition and induction of apoptosis in LSCC cells.

Conclusions

miR-125a suppressed LSCC progression by targeting HK2 in vitro and in vivo, suggesting that miR-125a may be a potential molecular target for LSCC treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13578-017-0178-y) contains supplementary material, which is available to authorized users.

Overexpression of miR-26b decreases the cisplatin-resistance in laryngeal cancer by targeting ATF2

Cisplatin is a common used chemotherapeutic drug for the treatment of laryngeal cancer. However, drug-resistance is a major obstacle in platinum-based chemotherapy for laryngeal cancer. Recent studies have demonstrated that dysregulation of microRNAs (miRNAs) is responsible for chemoresistance in multiple cancers including laryngeal cancer, but the potential mechanisms are required to be explored. In the present study, we constantly exposed the laryngeal cancer cell line Hep-2 with cisplatin to establish a cisplatin-resistant laryngeal cancer cell model (Hep-2/R). We found that Hep-2/R cells exhibited obvious resistance to cisplatin compared to the Hep-2 cells. However, overexpression of miR-26b significantly decreased the half maximal inhibitory concentration (IC50) of cisplatin to Hep-2/R. Mechanically, miR-26b in Hep-2/R decreased the expression of ATF2, and thus inhibiting the phosphorylation of ATF2 and formation of cellular ATF2-c-Jun complex induced by cisplatin. As the results, Hep-2/R cells failed to overexpress the Bcl-xl which is a key anti-apoptotic protein under the cisplatin treatment. Therefore, overexpression of miR-26b was found to be able to promote mitochondrial apoptosis induced by cisplatin.

Metformin partially reverses the carboplatin-resistance in NSCLC by inhibiting glucose metabolism

Platinum-based chemotherapeutic drugs are irreplaceable for the treatment of advanced non-small cell lung cancer (NSCLC). However, acquired drug resistance has become a major obstacle for the clinical application of chemotherapy on NSCLC. In the present study, we established carboplatin-resistant NSCLC models on A549 and PC9 cell lines, which were named A549/R and PC9/R. Besides the low sensitivity of A549/R and PC9/R to carboplatin treatment, they exhibited higher metabolism rate of glucose compared to their parental A549 and PC9 cells, respectively. Mechanically, we confirmed that overexpression of PKM2 in A549/R and PC9/R was responsible for the high glucose metabolism and carboplatin resistance. Metformin, an antidiabetic drug, was observed to increase the sensitivity of carboplatin-resistant NSCLC cells to carboplatin treatment in vitro and in vivo. Mechanically, metformin decreased expression of PKM2 and subsequently inhibited the glucose uptake, lactate generation and ATP production in A549/R and PC9/R. Therefore, metformin promoted carboplatin-induced apoptosis through the mitochondria pathway. In addition, we demonstrated that metformin treatment also impaired the cross-resistance of A549/R and PC9/R to cisplatin, etoposide and 5-fluorouracil.

Restoration of secreted frizzled-related protein 1 suppresses growth and increases cisplatin sensitivity in laryngeal carcinoma cells by downregulating NHE1

It has been documented that secreted frizzled-related protein 1 (SFRP1) is epigenetically silenced in laryngeal carcinoma. However, the function of SFRP1 in laryngeal carcinoma remains elusive. In this study, we performed gain-of-function studies to determine the roles of SFRP1 in laryngeal carcinoma growth, tumorigenesis, and cisplatin resistance. Laryngeal carcinoma cell lines were treated with 5-aza-2'-deoxycytidine (5-aza-dC) and examined for SFRP1 expression. The effects of overexpression of SFRP1 on cell proliferation, colony formation, apoptosis, tumorigenesis, and cisplatin sensitivity were assessed. It was found that 5-aza-dC exposure significantly induced the expression of SFRP1 in both Hep-2 and SNU899 laryngeal carcinoma cells. Ectopic expression of SFRP1 significantly decreased cell proliferation and colony formation in vitro and retarded xenograft tumor growth in vivo. SFRP1-overexpressing Hep-2 cells displayed a higher percentage of apoptosis and enhancement of caspase-3 cleavage, which was coupled with loss of Δψm and increased release of cytochrome c from the mitochondria to the cytosol. Moreover, SFRP1 overexpression sensitized laryngeal carcinoma cells to cisplatin and decreased intracellular pH values. Mechanistically, SFRP1 inhibited the expression of Na+/H+ exchanger 1 (NHE1) and overexpression of NHE1 reversed the suppressive activity of SFRP1 on laryngeal carcinoma cells. In conclusion, we demonstrate that SFRP1 induces mitochondrial apoptosis and increases cisplatin sensitivity in laryngeal carcinoma cells via downregulation of NHE1. Delivery of SFRP1 may offer therapeutic benefits in the treatment of laryngeal carcinoma.

Metformin increases sensitivity of osteosarcoma stem cells to cisplatin by inhibiting expression of PKM2

Multiple drug resistance is reported to be a major obstacle in treatment of osteosarcoma (OS). Research has demonstrated that small subsets of cells called cancer stem cells (CSCs) are responsible for multiple drug resistance. CSCs are potential targets for reversing chemoresistance. In the present study, we compared cisplatin sensitivity between OS stem cells and OS non-stem cells. We confirmed that OS stem cells showed significant cisplatin-resistance compared with the OS non-CSCs. Mechanically, we proved that overexpression of the pyruvate kinase isoenzyme M2 (PKM2) was responsible for the resistance to cisplatin in OS stem cells. As a potential strategy, we found that co-treatment with metformin significantly decreased the half maximal inhibitory concentration (IC50) of cisplatin to HOS OS stem cells by downregulating the expression of PKM2. PKM2 downregulation resulted in, metformin inhibited glucose uptake, lactate production and ATP production in HOS CSCs. Therefore, metformin impaired the resistance of HOS CSCs to cisplatin and promoted cisplatin-induced apoptosis. In addition, antitumor effects of other chemotherapeutic drugs such as doxorubicin and 5-fluorouracil were proved to be enhanced by metformin on OS stem cells.