Mitochondrial metabolism is inhibited by the HIF 1α‐ MYC ‐ PGC ‐1β axis in BRAF V600E thyroid cancer

Fasting regulates mitochondrial function through lncRNA PRKCQ-AS1-mediated IGF2BPs in papillary thyroid carcinoma

Recurring evidence suggests that fasting has extensive antitumor effects in various cancers, including papillary thyroid carcinoma (PTC). However, the underlying mechanism of this relationship with PTC is unknown. In this study, we study the effect of fasting on glycolysis and mitochondrial function in PTC. We find that fasting impairs glycolysis and reduces mitochondrial dysfunction in vitro and in vivo and also fasting in vitro and fasting mimicking diets (FMD) in vivo significantly increase the expression of lncRNA-protein kinase C theta antisense RNA 1 (PRKCQ-AS1), during the inhibition of TPC cell glycolysis and mitochondrial function. Moreover, lncRNA PRKCQ-AS1 was significantly lower in PTC tissues and cells. In addition, PRKCQ-AS1 overexpression increased PTC cell glycolysis and mitochondrial function; PRKCQ-AS1 knockdown has the opposite effect. On further mechanistic analysis, we identified that PRKCQ-AS1 physically interacts with IGF2BPs and enhances protein arginine methyltransferases 7 (PRMT7) mRNA, which is the key player in regulating glycolysis and mitochondrial function in PTC. Hence, PRKCQ-AS1 inhibits tumor growth while regulating glycolysis and mitochondrial functions via IGF2BPs/PRMT7 signaling. These results indicate that lncRNA PRKCQ-AS1 is a key downstream target of fasting and is involved in PTC metabolic reprogramming. Further, the PRKCQ-AS1/IGF2BPs/PRMT7 axis is an ideal therapeutic target for PTC diagnosis and treatment.

The potential role of reprogrammed glucose metabolism: an emerging actionable codependent target in thyroid cancer

Although the incidence of thyroid cancer is increasing year by year, most patients, especially those with differentiated thyroid cancer, can usually be cured with surgery, radioactive iodine, and thyroid-stimulating hormone suppression. However, treatment options for patients with poorly differentiated thyroid cancers or radioiodine-refractory thyroid cancer have historically been limited. Altered energy metabolism is one of the hallmarks of cancer and a well-documented feature in thyroid cancer. In a hypoxic environment with extreme nutrient deficiencies resulting from uncontrolled growth, thyroid cancer cells utilize "metabolic reprogramming" to satisfy their energy demand and support malignant behaviors such as metastasis. This review summarizes past and recent advances in our understanding of the reprogramming of glucose metabolism in thyroid cancer cells, which we expect will yield new therapeutic approaches for patients with special pathological types of thyroid cancer by targeting reprogrammed glucose metabolism.

Tumor Cell Resistance to the Inhibition of BRAF and MEK1/2

BRAF is one of the most frequently mutated oncogenes, with an overall frequency of about 50%. Targeting BRAF and its effector mitogen-activated protein kinase kinase 1/2 (MEK1/2) is now a key therapeutic strategy for BRAF-mutant tumors, and therapies based on dual BRAF/MEK inhibition showed significant efficacy in a broad spectrum of BRAF tumors. Nonetheless, BRAF/MEK inhibition therapy is not always effective for BRAF tumor suppression, and significant challenges remain to improve its clinical outcomes. First, certain BRAF tumors have an intrinsic ability to rapidly adapt to the presence of BRAF and MEK1/2 inhibitors by bypassing drug effects via rewired signaling, metabolic, and regulatory networks. Second, almost all tumors initially responsive to BRAF and MEK1/2 inhibitors eventually acquire therapy resistance via an additional genetic or epigenetic alteration(s). Overcoming these challenges requires identifying the molecular mechanism underlying tumor cell resistance to BRAF and MEK inhibitors and analyzing their specificity in different BRAF tumors. This review aims to update this information.

Little things with significant impact: miRNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has developed into one of the most lethal, aggressive, and malignant cancers worldwide. Although HCC treatment has improved in recent years, the incidence and lethality of HCC continue to increase yearly. Therefore, an in-depth study of the pathogenesis of HCC and the search for more reliable therapeutic targets are crucial to improving the survival quality of HCC patients. Currently, miRNAs have become one of the hotspots in life science research, which are widely present in living organisms and are non-coding RNAs involved in regulating gene expression. MiRNAs exert their biological roles by suppressing the expression of downstream genes and are engaged in various HCC-related processes, including proliferation, apoptosis, invasion, and metastasis. In addition, the expression status of miRNAs is related to the drug resistance mechanism of HCC, which has important implications for the systemic treatment of HCC. This paper reviews the regulatory role of miRNAs in the pathogenesis of HCC and the clinical applications of miRNAs in HCC in recent years.

Integrative analysis of small non-coding RNAs predicts a piRNA/miRNA-CCND1/BRAF/HRH1/ATXN3 regulatory circuit that drives oncogenesis in glioblastoma

The high-grade astrocytoma, glioblastoma multiforme (GBM), is the most common primary tumour of the brain, known for being aggressive and developing drug resistance. The non-coding RNAs (ncRNAs), such as microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), have critical functions in tumorigenesis and cancer drug resistance. Hence, we profiled miRNAs, piRNAs, and genes in U-87 MG GBM cells by next-generation sequencing and performed target prediction, pathway enrichment, protein-protein interaction, co-expression studies, and qRT-PCR validations to predict their possible roles in the malignancy. The study identified 335 miRNAs, 665 piRNAs, and 4286 genes differentially expressed (DE) in GBM. Among them 128 DE genes (DEGs) were targeted by both miRNAs and piRNAs, while 1817 and 192 were targeted solely by miRNAs or piRNAs, respectively. Interestingly, all the DEG targets enriched in cancer processes were overexpressed in GBM. Among these, BRAF was solely targeted by two piRNAs and this was found to be co-expressed with 19 sole targets of 5 miRNAs, including CCND1, and both were found to regulate cell proliferation in cancer. We conjectured that upregulated HRH1 and ATXN3 were targeted by both piRNAs and miRNAs, and along with BRAF and CCND1 might induce cell proliferation in GBM through G-protein-coupled receptor or Akt signalling pathways due to downregulation of the respective targeting small RNAs. These targets were also linked to the progression and overall survival of GBM patients, suggesting that they could be used as biomarkers. Overall, this study has identified a few novel ncRNA targets, which might aid in a better understanding of GBM pathogenesis.

Reprogramming of Cellular Metabolism and Its Therapeutic Applications in Thyroid Cancer

Metabolism is a series of life-sustaining chemical reactions in organisms, providing energy required for cellular processes and building blocks for cellular constituents of proteins, lipids, carbohydrates and nucleic acids. Cancer cells frequently reprogram their metabolic behaviors to adapt their rapid proliferation and altered tumor microenvironments. Not only aerobic glycolysis (also termed the Warburg effect) but also altered mitochondrial metabolism, amino acid metabolism and lipid metabolism play important roles for cancer growth and aggressiveness. Thus, the mechanistic elucidation of these metabolic changes is invaluable for understanding the pathogenesis of cancers and developing novel metabolism-targeted therapies. In this review article, we first provide an overview of essential metabolic mechanisms, and then summarize the recent findings of metabolic reprogramming and the recent reports of metabolism-targeted therapies for thyroid cancer.

Ursolic acid augments the chemosensitivity of drug-resistant breast cancer cells to doxorubicin by AMPK-mediated mitochondrial dysfunction

Multidrug resistance remains the major obstacle to successful therapy for breast carcinoma. Ursolic acid (UA), a triterpenoid compound, has been regarded as a potential neoplasm chemopreventive drug in some preclinical studies since it exerts multiple biological activities. In this research, we investigated the role of UA in augmenting the chemosensitivity of drug-resistant breast carcinoma cells to doxorubicin (DOX), and we further explored the possible molecular mechanisms. Notably, we found that UA treatment led to inhibition of cellular proliferation and migration and cell cycle arrest in DOX-resistant breast cancers. Furthermore, combination treatment with UA and DOX showed a stronger inhibitory effect on cell viability, colony formation, and cell migration; induced more cell apoptosis in vitro; and generated a more potent inhibitory effect on the growth of the MCF-7/ADR xenograft tumor model than DOX alone. Mechanistically, UA effectively increased p-AMPK levels and concomitantly reduced p-mTOR and PGC-1α protein levels, resulting in impaired mitochondrial function, such as mitochondrial respiration inhibition, ATP depletion, and excessive reactive oxygen species (ROS) generation. In addition, UA induced a DNA damage response by increasing intracellular ROS production, thus causing cell cycle arrest at the G0/G1 phase. UA also suppressed aerobic glycolysis by prohibiting the expression and function of Glut1. Considered together, our data demonstrated that UA potentiated the susceptibility of DOX-resistant breast carcinoma cells to DOX by targeting energy metabolism through the AMPK/mTOR/PGC-1α signaling pathway, and it is a potential adjuvant chemotherapeutic candidate in MDR breast cancer.

Mitochondrial Respiration Inhibition Suppresses Papillary Thyroid Carcinoma Via PI3K/Akt/FoxO1/Cyclin D1 Pathway

Background

Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy, but little is known regarding PTC metabolic phenotypes and the effects of mitochondrial activity on PTC progression. The great potential of mitochondria-targeting therapy in cancer treatment promoted us to use tool compounds from a family of Mito-Fu derivatives to investigate how the regulation of mitochondrial respiration affected tumor progression characteristics and molecular changes in PTC.

Methods

Mito-Fu L20, a representative of 12 synthetic derivatives, was chosen for mitochondrial inhibition experiments. Sample sections from PTC patients were collected and processed to explore potential molecular alterations in tumor lymph node metastasis (LNM). In vitro analyses were performed using human PTC cell lines (K1 and TPC-1), with the human normal thyroid follicular cell line (Nthy) as a control. K1 cells were injected into nude mice to generate an animal model. The mice were injected with normal saline or Mito-Fu L20 at 20 or 50 mg/kg every other day; their body weights and tumor volumes were also measured over time. To elucidate the resulting metabolic phenotype, we measured oxygen consumption rate (OCR) and extracellular acidification rate (ECAR), cellular adenosine triphosphate (ATP) levels and reactive oxygen species (ROS) production, and mitochondrial membrane potential. Wound healing and Transwell assays, cell cycle assays, real-time fluorescence quantitative PCR, Western blotting, and immunohistochemical staining were performed to explore glycolysis-dominant metabolism in PTC.

Results

Cyclin D1 and mitochondrial complex IV were detected in tumor samples from PTC patients with LNM. Mito-Fu L20 showed dose-independent and reversible modulation of mitochondrial respiration in PTC. In addition to mitochondrial dysfunction and early apoptosis, G1/S phase arrest. Notably, reversible mitochondrial inhibition yielded durable suppression of tumor proliferation, migration, and invasion via the PI3K/Akt/FoxO1/Cyclin D1 pathway. In vivo experiments demonstrated that Mito-Fu L20 has a good safety profile and specific restorative effect on mitochondrial activity in the liver. In addition, Mito-Fu L20 showed antitumor effects, alleviated tumor angiogenesis, and improved thyroid function.

Conclusion

Reversible inhibition of ATP production and durable suppression of PTC growth indicates that the downregulation of mitochondrial function has a negative impact on tumor progression and LNM via the PI3K/Akt/FoxO1/Cyclin D1 pathway. The results provide new insights into the antitumor potential and clinical translation of mitochondrial inhibitors.

BRAF V600E protect from cell death via inhibition of the mitochondrial permeability transition in papillary and anaplastic thyroid cancers

BRAF T1799A mutation is the most common genetic variation in thyroid cancer, resulting in the production of BRAF V600E mutant protein reported to make cells resistant to apoptosis. However, the mechanism by which BRAF V600E regulates cell death remains unknown. We constructed BRAF V600E overexpression and knockdown 8505C and BCPAP papillary and anaplastic thyroid cancer cell to investigate regulatory mechanism of BRAF V600E in cell death induced by staurosporine (STS). Induced BRAF V600E expression attenuated STS-induced papillary and anaplastic thyroid cancer death, while BRAF V600E knockdown aggravated it. TMRM and calcein-AM staining showed that opening of the mitochondrial permeability transition pore (mPTP) during STS-induced cell death could be significantly inhibited by BRAF V600E. Moreover, our study demonstrated that BRAF V600E constitutively activates mitochondrial ERK (mERK) to inhibit GSK-3-dependent CypD phosphorylation, thereby making BRAF V600E mutant tumour cells more resistant to mPTP opening. In the mitochondria of BRAF V600E mutant cells, there was an interaction between ERK1/2 and GSKa/ß, while upon BRAF V600E knockdown, interaction of GSKa/ß to ERK was decreased significantly. These results show that in thyroid cancer, BRAF V600E regulates the mitochondrial permeability transition through the pERK-pGSK-CypD pathway to resist death, providing new intervention targets for BRAF V600E mutant tumours.

Metabolic Reprogramming in Cancer Cells: Emerging Molecular Mechanisms and Novel Therapeutic Approaches

The constant changes in cancer cell bioenergetics are widely known as metabolic reprogramming. Reprogramming is a process mediated by multiple factors, including oncogenes, growth factors, hypoxia-induced factors, and the loss of suppressor gene function, which support malignant transformation and tumor development in addition to cell heterogeneity. Consequently, this hallmark promotes resistance to conventional anti-tumor therapies by adapting to the drastic changes in the nutrient microenvironment that these therapies entail. Therefore, it represents a revolutionary landscape during cancer progression that could be useful for developing new and improved therapeutic strategies targeting alterations in cancer cell metabolism, such as the deregulated mTOR and PI3K pathways. Understanding the complex interactions of the underlying mechanisms of metabolic reprogramming during cancer initiation and progression is an active study field. Recently, novel approaches are being used to effectively battle and eliminate malignant cells. These include biguanides, mTOR inhibitors, glutaminase inhibition, and ion channels as drug targets. This review aims to provide a general overview of metabolic reprogramming, summarise recent progress in this field, and emphasize its use as an effective therapeutic target against cancer.

Papillary thyroid carcinoma tall cell variant shares accumulation of mitochondria, mitochondrial DNA mutations, and loss of oxidative phosphorylation complex I integrity with oncocytic tumors

Papillary thyroid carcinoma tall cell variant (PTC-TCV), a form of PTC regarded as an aggressive subtype, shares several morphologic features with oncocytic tumors. Pathogenic homoplasmic/highly heteroplasmic somatic mitochondrial DNA (mtDNA) mutations, usually affecting oxidative phosphorylation (OXPHOS) complex I subunits, are hallmarks of oncocytic cells. To clarify the relationship between PTC-TCV and oncocytic thyroid tumors, 17 PTC-TCV and 16 PTC non-TCV controls (cPTC) were subjected to: (1) transmission electron microscopy (TEM) to assess mitochondria accumulation, (2) next-generation sequencing to analyze mtDNA and nuclear genes frequently mutated in thyroid carcinoma, and (3) immunohistochemistry (IHC) for prohibitin and complex I subunit NDUFS4 to evaluate OXPHOS integrity. TEM showed replacement of cytoplasm by mitochondria in PTC-TCV but not in cPTC cells. All 17 PTC-TCV had at least one mtDNA mutation, totaling 21 mutations; 3/16 cPTC (19%) had mtDNA mutations (p < 0.001). PTC-TCV mtDNA mutations were homoplasmic/highly heteroplasmic, 16/21 (76%) mapping within mtDNA-encoded complex I subunits. MtDNA mutations in cPTC were homoplasmic in 2 cases and at low heteroplasmy in the third case, 2/3 mapping to mtDNA-encoded complex I subunits; 2/3 cPTC with mtDNA mutations had small tall cell subpopulations. PTC-TCV showed strong prohibitin expression and cPTC low-level expression, consistent with massive and limited mitochondrial content, respectively. All 17 PTC-TCV showed NDUFS4 loss (partial or complete) and 3 of 16 cPTC (19%) had (partial) NDUFS4 loss, consistent with lack of complex I integrity in PTC-TCV (p < 0.001). IHC loss of NDUFS4 was associated with mtDNA mutations (p < 0.001). Four BRAF V600E mutated PTCs had loss of NDUSF4 expression limited to neoplastic cell subpopulations with tall cell features, indicating that PTCs first acquire BRAF V600E and then mtDNA mutations. Similar to oncocytic thyroid tumors, PTC-TCV is characterized by mtDNA mutations, massive accumulation of mitochondria, and loss of OXPHOS integrity. IHC loss of NDUFS-4 can be used as a surrogate marker for OXPHOS disruption and to reliably diagnose PTC-TCV.

Metformin and Cancer Hallmarks: Molecular Mechanisms in Thyroid, Prostate and Head and Neck Cancer Models

Metformin is the most used drug for type 2 diabetes (T2DM). Its antitumor activity has been described by clinical studies showing reduced risk of cancer development in T2DM patients, as well as management of T2DM compared with those receiving other glucose-lowering drugs. Metformin has a plethora of molecular actions in cancer cells. This review focused on in vitro data on the action mechanisms of metformin on thyroid, prostate and head and neck cancer. AMPK activation regulating specific downstream targets is a constant antineoplastic activity in different types of cancer; however, AMPK-independent mechanisms are also relevant. In vitro evidence makes it clear that depending on the type of tumor, metformin has different actions; its effects may be modulated by different cell conditions (for instance, presence of HPV infection), or it may regulate tissue-specific factors, such as the Na⁺/I⁻ symporter (NIS) and androgen receptors. The hallmarks of cancer are a set of functional features acquired by the cell during malignant development. In vitro studies show that metformin regulates almost all the hallmarks of cancer. Interestingly, metformin is one of these therapeutic agents with the potential to synergize with other chemotherapeutic agents, with low cost, low side effects and high positive consequences. Some questions are still challenging: Are metformin in vitro data able to translate from bench to bedside? Does metformin affect drug resistance? Can metformin be used as a generic anticancer drug for all types of tumors? Which are the specific actions of metformin on the peculiarities of each type of cancer? Several clinical trials are in progress or have been concluded for repurposing metformin as an anticancer drug. The continuous efforts in the field and future in vitro studies will be essential to corroborate clinical trials results and to elucidate the raised questions.

Metabolic Reprogramming of Thyroid Cancer Cells and Crosstalk in Their Microenvironment

Metabolism differs significantly between tumor and normal cells. Metabolic reprogramming in cancer cells and metabolic interplay in the tumor microenvironment (TME) are important for tumor formation and progression. Tumor cells show changes in both catabolism and anabolism. Altered aerobic glycolysis, known as the Warburg effect, is a well-recognized characteristic of tumor cell energy metabolism. Compared with normal cells, tumor cells consume more glucose and glutamine. The enhanced anabolism in tumor cells includes de novo lipid synthesis as well as protein and nucleic acid synthesis. Although these forms of energy supply are uneconomical, they are required for the functioning of cancer cells, including those in thyroid cancer (TC). Increasing attention has recently focused on alterations of the TME. Understanding the metabolic changes governing the intricate relationship between TC cells and the TME may provide novel ideas for the treatment of TC.

Physciosporin suppresses mitochondrial respiration, aerobic glycolysis, and tumorigenesis in breast cancer

BACKGROUND

Physciosporin (PHY) is one of the potent anticancer lichen compound. Recently, PHY was shown to suppress colorectal cancer cell proliferation, motility, and tumorigenesis through novel mechanisms of action.

PURPOSE

We investigated the effects of PHY on energy metabolism and tumorigenicity of the human breast cancer (BC) cells MCF-7 (estrogen and progesterone positive BC) and MDA-MB-231 (triple negative BC).

METHODS

The anticancer effect of PHY on cell viability, motility, cancer metabolism and tumorigenicity was evaluated by MTT assay, migration assay, clonogenic assay, anchorage-independent colony formation assay, glycolytic and mitochondrial metabolism analysis, qRT-PCR, flow cytometric analysis, Western blotting, immunohistochemistry in vitro; and by tumorigenicity study with orthotopic breast cancer xenograft model in vivo.

RESULTS

PHY markedly inhibited BC cell viability. Cell-cycle profiling and Annexin V-FITC/PI double staining showed that a toxic dosage of PHY triggered apoptosis in BC cell lines by regulating the B-cell lymphoma-2 (Bcl-2) family proteins and the activity of caspase pathway. At non-toxic concentrations, PHY potently decreased migration, proliferation, and tumorigenesis of BC cells in vitro. Metabolic studies revealed that PHY treatment significantly reduced the bioenergetic profile by decreasing respiration, ATP production, and glycolysis capacity. In addition, PHY significantly altered the levels of mitochondrial (PGC-1α) and glycolysis (GLUT1, HK2 and PKM2) markers, and downregulated transcriptional regulators involved in cancer cell metabolism, including β-catenin, c-Myc, HIF-1α, and NF-κB. An orthotopic implantation mouse model of BC confirmed that PHY treatment suppressed BC growth in vivo and target genes were consistently suppressed in tumor specimens.

CONCLUSION

The findings from our in vitro as well as in vivo studies exhibit that PHY suppresses energy metabolism as well as tumorigenesis in BC. Especially, PHY represents a promising therapeutic effect against hormone-insensitive BC (triple negative) by targeting energy metabolism.

STAT3/LINC00671 axis regulates papillary thyroid tumor growth and metastasis via LDHA-mediated glycolysis

Lactate dehydrogenase A (LDHA), a critical component of the glycolytic pathway, relates to the development of various cancers, including thyroid cancer. However, the regulatory mechanism of LDHA inhibition and the physiological significance of the LDHA inhibitors in papillary thyroid cancer (PTC) are unknown. Long non-coding RNA (lncRNA) plays a vital role in tumor growth and progression. Here, we identified a novel lncRNA LINC00671 negatively correlated with LDHA, downregulating LDHA expression and predicting good clinical outcome in thyroid cancer. Moreover, hypoxia inhibits LINC00671 expression and activates LDHA expression largely through transcriptional factor STAT3. STAT3/LINC00671/LDHA axis regulates thyroid cancer glycolysis, growth, and lung metastasis both in vitro and in vivo. In thyroid cancer patients, LINC00671 expression is negatively correlated with LDHA and STAT3 expression. Our work established STAT3/LINC00671/LDHA as a critical axis to regulate PTC growth and progression. Inhibition of LDHA or STAT3 or supplement of LINC00671 could be potential therapeutic strategies in thyroid cancer.

Signaling, metabolism, and cancer: An important relationship for therapeutic intervention

In cancerous cells, significant changes occur in the activity of signaling pathways affecting a wide range of cellular activities ranging from growth and proliferation to apoptosis, invasiveness, and metastasis. Extensive changes also happen with respect to the metabolism of a cancerous cell encompassing a wide range of functions that include: nutrient acquisition, biosynthesis of macromolecules, and energy generation. These changes are important and some therapeutic approaches for treating cancers have focused on targeting the metabolism of cancerous cells. Oncogenes and tumor suppressor genes have a significant effect on the metabolism of cells. There appears to be a close interaction between metabolism and the signaling pathways in a cancerous cell, in which the interaction provides the metabolic needs of a cancerous cell for uncontrolled proliferation, resistance to apoptosis, and metastasis. In this review, we have reviewed the latest findings in this regard and briefly review the most recent research findings regarding targeting the metabolism of cancer cells as a therapeutic approach for treatment of cancer.

Mitochondrial miR-181a-5p promotes glucose metabolism reprogramming in liver cancer by regulating the electron transport chain

Liver cancer and other malignant tumor cells rely on the glycolytic pathway to obtain energy (i.e. the Warburg effect); however, the underlying mechanism is unclear. Mitochondria are sites of oxidative phosphorylation and adenosine triphosphate (ATP) production. The 13 constituent respiratory chain proteins encoded by the mitochondrial genome (namely, mtDNA) play essential roles. We found that in human hepatocellular carcinoma (HCC) tissues, 11 out of the 13 mtDNA-encoded genes exhibited decreased mRNA levels and 5 genes displayed decreased protein levels, including the cytochrome B (mt-CYB) and cytochrome C oxidase II (mt-CO2) genes. Mitochondrial gene sequencing revealed abnormalities in the levels of a large number of mitochondrial miRNAs (mitomiRs). MicroRNA-181a-5p (mir-181a-5p), which potentially targets genes encoding mt-CYB and mt-CO2 protein, was screened out from 549 downregulated mitomiRs via bioinformatic analysis. After overexpression of mitomiR-181a-5p, mt-CYB and mt-CO2 levels were reduced in HCC cells, and the mitochondrial membrane potential (MMP) maintained by the electron transport chain (ETC) was decreased. Furthermore, the expression of hexokinase 2 (HK2) and glucose transporter type 1 (GLUT1) was upregulated, accompanied by elevated glucose, lactic acid release, and activity of lactate dehydrogenase (LDH). In vivo experiments confirmed that constitutive mitomiR-181a-5p expression caused reprogramming of glucose metabolism and promoted tumor growth and early lung metastasis in liver cancer. In summary, the present study reveals the important role of mitomiRs in glucose metabolism reprogramming in liver cancer, which is of considerable value in exploring new therapeutic targets for HCC.

Lactate Dehydrogenase A as a Potential New Biomarker for Thyroid Cancer

BACKGROUND

Several cancers show increased levels of lactate dehydrogenase A (LDHA), which are associated with cancer progression. However, it remains unclear whether LDHA levels are associated with papillary thyroid cancer (PTC) aggressiveness or with the presence of the PTC prognostic marker, the BRAFV600E mutation. This study aimed to evaluate the potential of LDHA as a PTC prognostic marker.

METHODS

LDHA expression was examined in 83 PTC tissue specimens by immunohistochemistry. Human thyroid cell lines were genetically manipulated to overexpress BRAFV600E or were treated with a BRAF-specific short hairpin RNA (shBRAF), whose effects on LDHA expression were evaluated by Western blotting. Data from 465 PTC patients were obtained from The Cancer Genome Atlas (TCGA) database and analyzed to validate the in vitro results.

RESULTS

LDHA was aberrantly overexpressed in PTC. Intense immunostaining for LDHA was observed in PTC specimens carrying mutated BRAF, whereas the intensity was less in wild-type BRAF samples. Overexpression of BRAFV600E resulted in LDHA upregulation, whereas treatment with shBRAF downregulated LDHA in human thyroid cell lines. Furthermore, LDHA mRNA expression was significantly elevated and associated with BRAFV600E expression in thyroid cancer tissues from TCGA database. Additionally, LDHA overexpression was found to be correlated with aggressive clinical features of PTC, such as lymph node metastases and advanced tumor stages.

CONCLUSION

LDHA overexpression is associated with the BRAFV600E mutation and an aggressive PTC behavior. Therefore, LDHA may serve as a biomarker and therapeutic target in PTC.

Long-term transcriptomic and proteomic effects in Sprague Dawley rat thyroid and plasma after internal low dose 131I exposure

Background

Radioiodide (¹³¹I) is commonly used to treat thyroid cancer and hyperthyroidis.¹³¹I released during nuclear accidents, have resulted in increased incidence of thyroid cancer in children. Therefore, a better understanding of underlying cellular mechanisms behind ¹³¹I exposure is of great clinical and radiation protection interest. The aim of this work was to study the long-term dose-related effects of ¹³¹I exposure in thyroid tissue and plasma in young rats and identify potential biomarkers.

Materials and methods

Male Sprague Dawley rats (5-week-old) were i.v. injected with 0.5, 5.0, 50 or 500 kBq ¹³¹I (D_thyroid ca 1–1000 mGy), and killed after nine months at which time the thyroid and blood samples were collected. Gene expression microarray analysis (thyroid samples) and LC-MS/MS analysis (thyroid and plasma samples) were performed to assess differential gene and protein expression profiles in treated and corresponding untreated control samples. Bioinformatics analyses were performed using the DAVID functional annotation tool and Ingenuity Pathway Analysis (IPA). The gene expression microarray data and LC-MS/MS data were validated using qRT-PCR and ELISA, respectively.

Results

Nine ¹³¹I exposure-related candidate biomarkers (transcripts: Afp and RT1-Bb, and proteins: ARF3, DLD, IKBKB, NONO, RAB6A, RPN2, and SLC25A5) were identified in thyroid tissue. Two dose-related protein candidate biomarkers were identified in thyroid (APRT and LDHA) and two in plasma (DSG4 and TGM3). Candidate biomarkers for thyroid function included the ACADL and SORBS2 (all activities), TPO and TG proteins (low activities). ¹³¹I exposure was shown to have a profound effect on metabolism, immune system, apoptosis and cell death. Furthermore, several signalling pathways essential for normal cellular function (actin cytoskeleton signalling, HGF signalling, NRF2-mediated oxidative stress, integrin signalling, calcium signalling) were also significantly regulated.

Conclusion

Exposure-related and dose-related effects on gene and protein expression generated few expression patterns useful as biomarkers for thyroid function and cancer.

Metabolomic Reprogramming Detected by 1H-NMR Spectroscopy in Human Thyroid Cancer Tissues

Thyroid cancer cells demonstrate an increase in oxidative stress and decreased antioxidant action, but the effects of this increased oxidative stress on cell function remain unknown. We aimed to identify changes in the metabolism of thyroid cancer cells caused by oxidative stress, using proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Samples of thyroid cancer and healthy thyroid tissue were collected from patients undergoing thyroidectomy and analyzed with ¹H-NMR spectroscopy for a wide array of metabolites. We found a significant increase in lactate content in thyroid cancer tissue compared to healthy tissue. Metabolomic analysis demonstrated significant differences between cancer tissue and healthy tissue, including an increase in aromatic amino acids, and an average decrease in citrate in thyroid cancer tissue. We hypothesize that these changes in metabolism may be due to an oxidative stress-related decrease in activity of the Krebs cycle, and a shift towards glycolysis in cancer tissue. Thus, thyroid cancer cells are able to reprogram their metabolic activity to survive in conditions of high oxidative stress and with a compromised antioxidant system. Our findings, for the first time, suggested a connection between oxidative stress and the alteration of the metabolic profile in thyroid tumors.

Multi-omics Signatures and Translational Potential to Improve Thyroid Cancer Patient Outcome

Recent advances in high-throughput molecular and multi-omics technologies have improved our understanding of the molecular changes associated with thyroid cancer initiation and progression. The translation into clinical use based on molecular profiling of thyroid tumors has allowed a significant improvement in patient risk stratification and in the identification of targeted therapies, and thereby better personalized disease management and outcome. This review compiles the following: (1) the major molecular alterations of the genome, epigenome, transcriptome, proteome, and metabolome found in all subtypes of thyroid cancer, thus demonstrating the complexity of these tumors and (2) the great translational potential of multi-omics studies to improve patient outcome.

MYC modulators in cancer: a patent review

INTRODUCTION

The important role of MYC in tumorigenesis makes it particularly important to design MYC modulators. Over the past decade, researchers have raised a number of strategies for designing MYC modulators, some of which are already in clinical trials. This paper aims to review the patents of MYC modulators.

AREAS COVERED

The important biological relevance of c-MYC and the regulation pathways related to c-MYC are briefly introduced. Base on that, the MYC modulators reported in published patents and references primarily for cancer treatment are outlined, highlighting the structures and biological activities.

EXPERT OPINION

There has been a growing awareness of finding and designing MYC modulators as novel anticancer drugs over recent years. Patents involving the discovery, synthesis, and application of MYC modulators are particularly important for further development in this field. Although finding direct MYC inhibitors or binders is challenging, MYC cannot be simply defined as an undruggable target. There is still substantial evidence proving the concept that MYC modulators can benefit to the treatment of both human hematological malignancies and solid tumors. More efforts should be taken to improve the activity and specificity of MYC modulators.

Leukocyte Mitochondrial DNA Copy Number and Risk of Thyroid Cancer: A Two-Stage Case-Control Study

Background: Mitochondrial DNA copy number (mtDNA-CN) may contribute to the development of various cancer types in a tumor-specific manner. However, little is known about whether leukocyte mtDNA content confers susceptibility to thyroid cancer (TC). This study aimed to investigate the associations of leukocyte mtDNA-CN with the risk and clinicopathological features of TC in a Chinese population. Methods: In this two-stage case-control study with a total of 402 TC patients and 406 controls, leukocyte mtDNA-CN content was measured with a quantitative PCR method. In a subset of 100 cases and 100 controls, levels of leukocyte 8-hydroxy-2'-deoxyguanosine (8-OHdG) and plasma malondialdehyde, as two biomarkers for oxidative stress, were determined by ELISA and colorimetric kits, respectively. Results: In a combined analysis of discovery and validation sets, high mtDNA-CN content was positively associated with increased TC risk, after adjusting for confounders (OR for per SD increment: 1.43; 95%CI, 1.23-1.66; P < 0.001; OR for tertile 3 vs. tertile 1: 2.10; 95%CI, 1.48-3.00; P _trend < 0.001). This linear dose-response relationship was more pronounced in subtype analyses for papillary and follicular thyroid carcinoma (P < 0.001 for all), as well as in subgroup analyses for subjects with overweight and obesity (P _interaction = 0.015). In TC patient, we observed the positive correlations of mtDNA-CN with advanced TNM stage (P = 0.006) and the presence of lymph node metastasis (P = 0.012). Leukocyte mtDNA-CN content was also identified to increase with the levels of leukocyte 8-OHdG (P < 0.001), a biomarker for oxidative DNA damage. Conclusion: Our data suggest that the increase in leukocyte mtDNA-CN content may correlate with oxidative DNA damage, and serve as an independent risk factor for TC.