Monocarboxylate Transporter 4 (MCT4) Overexpression Is Correlated with Poor Prognosis of Osteosarcoma

Energy Substrate Transporters in High-Grade Ovarian Cancer: Gene Expression and Clinical Implications

Ovarian cancer is a non-homogenous malignancy. High-grade serous carcinoma (HGSC) is the most common subtype, and its drug resistance mechanisms remain unclear. Despite the advantages of modern pharmacotherapy, high-grade ovarian cancer is associated with a poor prognosis and research into targeted therapies is in progress. The aim of the study was to assess the dominant energy substrate transport mechanism in ovarian cancer cells and to verify whether genomic aberrations could predict clinical outcomes using the Cancer Genome Atlas (TCGA) dataset. Total RNA was extracted from HGSC frozen tissues, and the expression of selected genes was compared to respective controls. GLUT1, FABPpm, MCT4 and SNAT1 genes were significantly overexpressed in carcinomas compared with controls, while expression of CD36/SR-B2, FATP1, FABP4, GLUT4, ASCT2 and LPL was decreased. No differences were found in FATP4, LAT1, MCT1 and FASN. The transcript content of mitochondrial genes such as PGC-1α, TFAM and COX4/1 was similar between groups, while the β-HAD level declined in ovarian cancer. Additionally, the MCT4 level was reduced and PGC-1α was elevated in cancer tissue from patients with ‘small’ primary tumor and omental invasion accompanied by ascites as compared to patients that exhibited greater tendencies to metastasize to lymph nodes with clear omentum. Based on TCGA, higher FABP4 and LPL and lower TFAM expression indicated poorer overall survival in patients with ovarian cancer. In conclusion, the presented data show that there is no exclusive energy substrate in HGSC. However, this study indicates the advantage of glucose and lactate transport over fatty acids, thereby suggesting potential therapeutic intervention targets to impede ovarian cancer growth.

TGF-β1 induced autophagy in cancer associated fibroblasts during hypoxia contributes EMT and glycolysis via MCT4 upregulation

The Transforming growth factor-β1(TGF- β1) in the tumor microenvironment(TME) is the major cytokine that acts as a mediator of tumor-stroma crosstalk, which in fact has a dual role in either promoting or suppressing tumor development. The cancer-associated fibroblasts (CAFs) are the major cell types in the TME, and the interaction with most of the epithelial cancers is the prime reason for cancer survival. However, the molecular mechanisms, associated with the TGF- β1 induced tumor promotion through tumor-CAF crosstalk are not well understood. In the Reverse Warburg effect, CAFs feed the adjacent cancer cells by lactate produced during the aerobic glycolysis. We hypothesized that the monocarboxylate transporter, MCT4 which is implicated in lactate efflux from the CAFs, must be overexpressed in the CAFs. Contextually, to explore the role of TGF- β1 in the hypoxia-induced autophagy in CAFs, we treated CoCl₂ and external TGF- β1 to the human dermal fibroblasts and L929 murine fibroblasts. We demonstrated that hypoxia accelerated the TGF- β1 signaling and subsequent transformation of normal fibroblasts to CAFs. Moreover, we elucidated that synergistic induction of autophagy by hypoxia and TGF- β1 upregulate the aerobic glycolysis and MCT4 expression in CAFs. Furthermore, we showed a positive correlation between glucose consumption and MCT4 expression in the CAFs. Autophagy was also found to be involved in the EMT in hypoxic CAFs. Collectively, these findings reveal the unappreciated role of autophagy in TME, which enhances the CAF transformation and that promotes tumor migration and metastasis via the reverse Warburg effect.

Osteoclasts differential-related prognostic biomarker for osteosarcoma based on single cell, bulk cell and gene expression datasets

Osteosarcoma (OS) is one of the most common primary bone malignant tumors. Osteoclasts have been shown to have a valuable role in OS. In the present study, we analyzed the differentiation states of osteoclasts in OS and their prognostic significance based on integrated scRNA-seq and bulk RNA-seq data. Osteoclasts in distinct differentiation states were characterized, and 661 osteoclasts differentiation-related genes (ODRGs) were obtained. ORDGs in distinct differentiation states were enriched in distinct functions and pathways. TPM1, S100A13, LOXL1, PSMD10, ST3GAL4, PEF1, SERPINE2, TUBB, FAM207A, TUBA1A, and DCN were identified as the significant survival-predicting ODRGs. We successfully developed a risk score model based on these survival-predicting ODRGs. In addition, we generated a nomogram applicable for clinical with both ODRGs signatures and clinicopathological parameters, and validated in OS cohorts to predict OS patient outcome. This study proposed and verified the important roles of osteoclasts differentiation in the prognosis of patients with OS, suggesting promising therapeutic targets for OS.

Construction of a competing endogenous RNA network related to the prognosis of cholangiocarcinoma and comprehensive analysis of the immunological correlation

Background

Cholangiocarcinoma (CCA) is a malignant tumor of the digestive system, with occult onset in the early stage, a high degree of malignancy in the late stage, and poor prognosis. At present, the pathogenesis of CCA is not clear, and there is a lack of effective immunotherapy. The purpose of this study was to identify the potential regulatory mechanism of CCA and analyze the possibility of its related immunotherapy.

Methods

The circular RNAs (circRNAs) expression profile data of CCA was downloaded from the Gene Expression Omnibus (GEO) database; the miRNA and mRNA expression profile data of CCA were downloaded from The Cancer Genome Atlas (TCGA) database. Prognostic factors were screened by univariate Cox regression analysis, and the competing endogenous RNA (ceRNA) network was constructed via survival analysis. Multivariate Cox analysis was used to screen the independent prognostic factors and construct a prognostic correlation subnetwork. Analyzing the tumor microenvironment of CCA and survival analysis were performed according to the score of the microenvironment, and the distribution of tumor infiltrating immune cells (TICs) in CCA was calculated using the CIBERSORT algorithm. We explored the expression pattern of the target genes in pan-cancer, and the correlation between the key genes in the ceRNA subnetwork, TICs and immune checkpoints was analyzed using an online database. Finally, the expression levels of target genes were validated based on the Human Protein Atlas (HPA) databases.

Results

We screened four circRNAs, 10 miRNAs, and 17 mRNAs with significant differences, and constructed the ceRNA network. Independent prognostic factors were screened by multivariate Cox regression analysis, and a subnetwork containing five nodes (hsa_circ_0002073→hsa-mir-4524a-3p→SLC16A3/SLC35E4/DDX4) was constructed. Further analysis showed that SLC16A3 was not only an independent posterior factor of CCA, but was also closely correlated with immune cells, immune checkpoints, and immunotherapy, and had a certain regulatory effect on the tumor microenvironment.

Conclusions

Our study identified a novel prognostic marker of CCA, SLC16A3, and revealed the regulatory role of SLC16A3 in the tumor microenvironment, which is expected to provide new insights for the early diagnosis, prognosis, and targeted therapy of CCA.

Acid Microenvironment in Bone Sarcomas

Simple Summary

Although rare, malignant bone sarcomas have devastating clinical implications for the health and survival of young adults and children. To date, efforts to identify the molecular drivers and targets have focused on cancer cells or on the interplay between cancer cells and stromal cells in the tumour microenvironment. On the contrary, in the current literature, the role of the chemical-physical conditions of the tumour microenvironment that may be implicated in sarcoma aggressiveness and progression are poorly reported and discussed. Among these, extracellular acidosis is a well-recognized hallmark of bone sarcomas and promotes cancer growth and dissemination but data presented on this topic are fragmented. Hence, we intended to provide a general and comprehensive overview of the causes and implications of acidosis in bone sarcoma.

Abstract

In bone sarcomas, extracellular proton accumulation is an intrinsic driver of malignancy. Extracellular acidosis increases stemness, invasion, angiogenesis, metastasis, and resistance to therapy of cancer cells. It reprograms tumour-associated stroma into a protumour phenotype through the release of inflammatory cytokines. It affects bone homeostasis, as extracellular proton accumulation is perceived by acid-sensing ion channels located at the cell membrane of normal bone cells. In bone, acidosis results from the altered glycolytic metabolism of bone cancer cells and the resorption activity of tumour-induced osteoclasts that share the same ecosystem. Proton extrusion activity is mediated by extruders and transporters located at the cell membrane of normal and transformed cells, including vacuolar ATPase and carbonic anhydrase IX, or by the release of highly acidic lysosomes by exocytosis. To date, a number of investigations have focused on the effects of acidosis and its inhibition in bone sarcomas, including studies evaluating the use of photodynamic therapy. In this review, we will discuss the current status of all findings on extracellular acidosis in bone sarcomas, with a specific focus on the characteristics of the bone microenvironment and the acid-targeting therapeutic approaches that are currently being evaluated.

Monocarboxylate Transporters 1 and 4 and MTCO1 in Gastric Cancer

Simple Summary

The expression of monocarboxylate transporters (MCTs) are reported in a variety of cancers and suggested as a therapeutic target for cancer treatment. However, previous study results in gastric cancer are contradictory. In this study, we evaluated the expression of MCT1, MCT4, and Mitochondrial cytochrome c oxidase (MTCO1) and their association with clinicopathological parameters and prognostic significance in a cohort of 568 surgically treated gastric cancer patients. The results suggest that monocarboxylate transporters and MTCO1 are associated with gastric cancer progression but have no independent prognostic relevance.

Abstract

Background: Monocarboxylate transporters (MCTs) appear to play an important role in tumor development and aggressiveness. The present study aimed to evaluate associations between cytoplasmic MCT1, MCT4, and mitochondrial cytochrome c oxidase (MTCO1) expression and clinicopathological variables or survival in gastric cancer. Material and methods: A total of 568 gastric adenocarcinoma patients were included in this retrospective cohort study. Protein expressions were detected by immunohistochemical staining. The patients were divided into low expression and high expression groups by median value. The Chi-squared test was used to compare categorical variables. The T-test was used to compare continuous variables. Expressions were analyzed in relation to 5-year survival and overall survival. Cox regression provided HRs and 95% CIs, adjusted for confounders. Results: High cytoplasmic MCT1 expression was associated statistically significantly with higher T-class (p = 0.020). High cytoplasmic MCT4 expression was associated statistically significantly with positive lymph node status (p = 0.005) and was more common in Lauren’s intestinal type (p < 0.001). Low cytoplasmic MTCO1 expression was associated statistically significantly with positive distant metastases (p = 0.030), and high cytoplasmic MTCO1 expression was associated more often with intestinal type (p = 0.044). However, MCT1, MCT4, and MTCO1 were not associated with survival. Conclusions: Monocarboxylate receptors seem to be associated with gastric cancer progression but have no independent prognostic relevance.

Pathogenesis and Current Treatment of Osteosarcoma: Perspectives for Future Therapies

Osteosarcoma is the most common primary malignant bone tumor in children and young adults. The standard-of-care curative treatment for osteosarcoma utilizes doxorubicin, cisplatin, and high-dose methotrexate, a standard that has not changed in more than 40 years. The development of patient-specific therapies requires an in-depth understanding of the unique genetics and biology of the tumor. Here, we discuss the role of normal bone biology in osteosarcomagenesis, highlighting the factors that drive normal osteoblast production, as well as abnormal osteosarcoma development. We then describe the pathology and current standard of care of osteosarcoma. Given the complex heterogeneity of osteosarcoma tumors, we explore the development of novel therapeutics for osteosarcoma that encompass a series of molecular targets. This analysis of pathogenic mechanisms will shed light on promising avenues for future therapeutic research in osteosarcoma.

High expression of monocarboxylate transporter 4 (MCT 4), but not MCT 1, predicts poor prognosis in patients with non-small cell lung cancer

BACKGROUND

The monocarboxylate transporter (MCT) family especially MCT1 and MCT4 have been recognized to play an important role in lactate transport, a key glycolytic product. The expression of MCT1 and MCT4 expression was previously found to be related to poor outcome in various cancer types. In this study, we investigated the expression status of MCT1 and MCT4 and their relationship with prognosis in non-small cell lung cancer (NSCLC).

METHODS

Expression of MCT4 and MCT1 in NSCLC tumor and adjacent lung tissues were detected by immunohistochemistry. Kaplan-Meier plots were used to evaluate two proteins' prognostic role, and the log-rank test obtained the P value. For multivariate analysis, the Cox proportional-hazards regression method was performed.

RESULTS

High MCT4 and MCT1 expression was observed in cancer cells, with a rate of 45% for MCT4 versus 15% for MCT1 among all NSCLC patients. High expression of MCT4, and not MCT1, was associated with worse overall survival (OS) [hazard ratio (HR) =1.96 (1.06-3.75), P=0.032] and progression-free survival (PFS) [HR =1.72 (1.05-2.93), P=0.032] in NSCLC patients. In our multivariate analysis, advanced cancer stage and high MCT4 level were identified as independent predictive indicators for both PFS [HR(MCT4) =1.888 (1.114-3.199), P=0.018 and OS [HR (MCT4) =2.421 (1.271-4.610), P=0.007]. Subgroup and interaction analyses were also performed in different clinical characteristic groups and no significant differences were observed.

CONCLUSIONS

High MCT4 expression is a predictive marker for worse outcome in NSCLC patients.