Hepatocellular Carcinoma Differentiation: Research Progress in Mechanism and Treatment

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor of the liver. Although progress has been made in diagnosis and treatment, morbidity and mortality continue to rise. Chronic liver disease and liver cirrhosis are still the most important risk factors for liver cancer. Although there are many treatments, it can only be cured by orthotopic liver transplantation (OLT) or surgical resection. And the worse the degree of differentiation, the worse the prognosis of patients with liver cancer. Then it can be considered that restoring a better state of differentiation may improve the prognosis. The differentiation treatment of liver cancer is to reverse the dedifferentiation process of hepatocytes to liver cancer cells by means of drugs, improve the differentiation state of the tumor, and restore the normal liver characteristics, so as to improve the prognosis. Understanding the mechanism of dedifferentiation of liver cancer can provide ideas for drug design. Liver enrichment of transcription factors, imbalance of signal pathway and changes of tumor microenvironment can promote the occurrence and development of liver cancer, and restoring its normal level can inhibit the malignant behavior of tumor. At present, some drugs have been proved to be effective, but more clinical data are needed to support the effectiveness and reliability of drugs. The differentiation treatment of liver cancer is expected to become an important part of the treatment of liver cancer in the future.

Rapid and inexpensive method of studying dedifferentiation in rabbit articular chondrocytes

Chondrocyte dedifferentiation is a cellular phenomenon in which chondrocyte loses its chondrogenic characteristics and ability to synthesize extracellular matrix. These conditions commonly reported in different cartilage degenerative diseases. The methods used to induce dedifferentiation in cell models of chondrocytes are often time consuming or require expensive reagents. Here in our protocol, we describe the utility of using 2-deoxy-D-glucose as a dedifferentiating agent for rabbit chondrocytes for studying dedifferentiation process.

Characterizing dedifferentiation of thyroid cancer by integrated analysis

Understanding of dedifferentiation, an indicator of poo prognosis for patients with thyroid cancer, has been hampered by imprecise and incomplete characterization of its heterogeneity and its attributes. Using single-cell RNA sequencing, we explored the landscape of thyroid cancer at single-cell resolution with 46,205 cells and delineated its dedifferentiation process and suppressive immune microenvironment. The developmental trajectory indicated that anaplastic thyroid cancer (ATC) cells were derived from a small subset of papillary thyroid cancer (PTC) cells. Moreover, a potential functional role of CREB3L1 on ATC development was revealed by integrated analyses of copy number alteration and transcriptional regulatory network. Multiple genes in differentiation-related pathways (e.g., EMT) were involved as the downstream targets of CREB3L1, increased expression of which can thus predict higher relapse risk of PTC. Collectively, our study provided insights into the heterogeneity and molecular evolution of thyroid cancer and highlighted the potential driver role of CREB3L1 in its dedifferentiation process.

A Brief Review of the Mechanisms of β-Cell Dedifferentiation in Type 2 Diabetes

Diabetes is a metabolic disease characterized by hyperglycemia. Over 90% of patients with diabetes have type 2 diabetes. Pancreatic β-cells are endocrine cells that produce and secrete insulin, an essential endocrine hormone that regulates blood glucose levels. Deficits in β-cell function and mass play key roles in the onset and progression of type 2 diabetes. Apoptosis has been considered as the main contributor of β-cell dysfunction and decrease in β-cell mass for a long time. However, recent studies suggest that β-cell failure occurs mainly due to increased β-cell dedifferentiation rather than limited β-cell proliferation or increased β-cell death. In this review, we summarize the current advances in the understanding of the pancreatic β-cell dedifferentiation process including potential mechanisms. A better understanding of β-cell dedifferentiation process will help to identify novel therapeutic targets to prevent and/or reverse β-cell loss in type 2 diabetes.

Genome-wide identification of microRNAs involved in the somatic embryogenesis of Eucalyptus

MicroRNAs (miRNAs) are small noncoding RNAs (18∼24 nt) and function in many biological processes in plants. Although Eucalyptus trees are widely planted across the world, our understanding of the miRNA regulation in the somatic embryogenesis (SE) of Eucalyptus is still poor. Here we reported, for the first time, the miRNA profiles of differentiated and dedifferentiated tissues of two Eucalyptus species and identified miRNAs involved in SE of Eucalyptus. Stem and tissue-culture induced callus were obtained from the subculture seedlings of E. camaldulensis and E. grandis x urophylla, and were used as differentiated and dedifferentiated samples, respectively. Small RNA sequencing generated 304.2 million clean reads for the Eucalyptus samples (n = 3) and identified 888 miRNA precursors (197 known and 691 novel) for Eucalyptus. These miRNAs were mainly distributed in chromosomes Chr03, Chr05 and Chr08, and can produce 46 miRNA clusters. Then, we identified 327 and 343 differentially expressed miRNAs (DEmiRs) in the dedifferentiation process of E. camaldulensis and E. grandis x urophylla, respectively. DEmiRs shared by the two Eucalyptus species might be involved in the development of embryonic callus, such as MIR156, MIR159, MIR160, MIR164, MIR166, MIR169, MIR171, MIR399 and MIR482. Notably, we identified 81 up-regulated and 67 down-regulated miRNAs specific to E. camaldulensis, which might be associated with the high embryogenic potential. Target prediction and functional analysis showed they might be involved in longevity regulating and plant hormone signal transduction pathways. Further, using the gene expression profiles we observed the negative regulation of miRNA∼target pairs, such as MIR160∼ARF18, MIR396∼GRF6, MIR166∼ATHB15/HD-ZIP and MIR156/MIR157∼SPL1. Interestingly, transcription factors such as WRKY, MYB, GAMYB, TCP4 and PIL1 were found to be regulated by the DEmiRs. The genes encoding PIL1 and RPS21C, regulated by up-regulated miRNAs (e.g., egd-N-miR63-5p, egd-N-miR63-5p and MIR169,) were down-regulated exclusively in the dedifferentiation of E. camaldulensis. This is the first time to study the miRNA regulation in the dedifferentiation process of Eucalyptus and it will provide a valuable resource for future studies. More importantly, it will improve our understanding of miRNA regulation during the somatic embryogenesis of Eucalyptus and benefit the Eucalyptus breeding program.

Genome-wide identification of microRNAs associated with the somatic embryogenesis in Eucalyptus

Background: MicroRNAs (miRNAs) are a class of small noncoding RNAs with 18-24 nucleotides in length and function in many biological processes in plant. Although Eucalyptus trees are widely planted across the world, our understanding of the miRNA regulation in the somatic embryogenesis of Eucalyptus is still poor. Here we reported for the first time the miRNA profiles of differentiated and dedifferentiated tissues of two Eucalyptus cultivars and identified miRNAs involved in the somatic embryogenesis of Eucalyptus.Results: Stem and tissue-culture induced callus were obtained from the subculture seedlings of E. camaldulensis and E. grandis x urophylla, and were used as differentiated and dedifferentiated samples, respectively. We generated 346.4 million reads for 12 samples (n=3) and identified 888 miRNA precursors (197 known and 691 novel) which can produce 1,067 mature miRNAs. These miRNAs were mainly distributed in chromosomes Chr03, Chr05 and Chr08, and can produce 46 miRNA clusters. In these samples we detected 998 miRNAs with TPM (transcripts per million reads) > 5 and found that highly expressed miRNAs varied across samples. We identified 327 and 343 differentially expressed miRNAs in the dedifferentiation process of E. camaldulensis and E. grandis x urophylla, respectively. Dysregulated miRNAs shared by the two cultivars might be involved in the development of embryonic callus of Eucalyptus, such as MIR156, MIR159, MIR160, MIR164, MIR166, MIR169, MIR171, MIR399 and MIR482. We also identified 81 up-regulated (e.g., miR159c-3p, miR167a-5p, miR397a-3p, miR397c-5p, miR397d-3p, miR397d-5p, N-miR1-5p and N-miR5-5p) and 67 down-regulated (e.g., miR482b-3p, N-miR3-3p, miR156a-3p, N-miR40-3p and N-miR18-5p) miRNAs specific to E. camaldulensis. Target prediction and functional analysis showed they might be involved in longevity regulating and plant hormone signal transduction pathways. Then, the expression patterns of these miRNAs were confirmed by qRT-PCR. Conclusions: This is the first time to study the miRNAs profiles in the dedifferentiation process of Eucalyptus and it will provide a valuable resource for future studies. More importantly, our findings will improve our understanding of miRNA regulation and molecular mechanisms during the somatic embryogenesis of Eucalyptus, and the output of this study will benefit the Eucalyptus breeding program.

Role of hemocytes in the regeneration of germline stem cells in Drosophila

Cellular regeneration, which relies on extensive restructuring of cytoplasmic materials, is an essential process to restore tissues and organs lost during aging, degenerative diseases and injury. At early stages of Drosophila spermatogenesis, when cellular constituents are intensely remodeled, there are two different populations of stem cells, the somatic stem cells and the germline stem cells (GSCs). GSCs divide by asymmetric division to give rise two distinct daughter cells. One of them will leave the stem cells’ niche and differentiate into spermatogonial cells (SCs). Both aging and cellular stress can lead to the loss of GSCs. Lost GSCs can be restored by dedifferentiation of SCs into functional GSCs. In other tissues, macrophages provide specific conditions for cellular transformation. Here we examined the potential role of immune surveillance cells called hemocytes during dedifferentiation of SGs into GSCs. We found an elevated number of hemocytes during this dedifferentiation process. Immune depletion of hemocytes decreased the regeneration capacity of germline. We also show that autophagy, which plays a pivotal role in cellular differentiation by eliminating unwanted, superfluous parts of the cytoplasm, becomes upregulated in dedifferentiating SCs upon JAK-STAT signaling emitted by hemocytes. Furthermore, these immune cells regulate expression of Omi/HtrA2, a key regulator of apoptosis in early spermatogenesis. Together, we suggest that hemocytes have important functions in the dedifferentiation process of GSCs.

Genome-Wide Identification of MicroRNAs Associated With the Somatic Embryogenesis in Eucalyptus

Background: MicroRNAs (miRNAs) are a class of small noncoding RNAs with 18-24 nucleotides in length and function in many biological processes in plant. Although Eucalyptus trees are widely planted across the world, our understanding of the miRNA regulation in the somatic embryogenesis of Eucalyptus is still poor. Here we reported for the first time the miRNA profiles of differentiated and dedifferentiated tissues of two Eucalyptus cultivars and identified miRNAs involved in the somatic embryogenesis of Eucalyptus.Results: Stem and tissue-culture induced callus were obtained from the subculture seedlings of E. camaldulensis and E. grandis x urophylla, and were used as differentiated and dedifferentiated samples, respectively. We generated 346.4 million reads for 12 samples (n=3) and identified 888 miRNA precursors (197 known and 691 novel) which can produce 1,067 mature miRNAs. These miRNAs were mainly distributed in chromosomes Chr03, Chr05 and Chr08, and can produce 46 miRNA clusters. In these samples we detected 998 miRNAs with TPM (transcripts per million reads) > 5 and found that highly expressed miRNAs varied across samples. We identified 327 and 343 differentially expressed miRNAs in the dedifferentiation process of E. camaldulensis and E. grandis x urophylla, respectively. Dysregulated miRNAs shared by the two cultivars might be involved in the development of embryonic callus of Eucalyptus, such as MIR156, MIR159, MIR160, MIR164, MIR166, MIR169, MIR171, MIR399 and MIR482. We also identified 81 up-regulated (e.g., miR159c-3p, miR167a-5p, miR397a-3p, miR397c-5p, miR397d-3p, miR397d-5p, N-miR1-5p and N-miR5-5p) and 67 down-regulated (e.g., miR482b-3p, N-miR3-3p, miR156a-3p, N-miR40-3p and N-miR18-5p) miRNAs specific to E. camaldulensis. Target prediction and functional analysis showed they might be involved in longevity regulating and plant hormone signal transduction pathways. Then, the expression patterns of these miRNAs were confirmed by qRT-PCR. Conclusions: This is the first time to study the miRNAs profiles in the dedifferentiation process of Eucalyptus and it will provide a valuable resource for future studies. More importantly, our findings will improve our understanding of miRNA regulation and molecular mechanisms during the somatic embryogenesis of Eucalyptus, and the output of this study will benefit the Eucalyptus breeding program.

Screening the Reference Genes for Quantitative Gene Expression by RT-qPCR During SE Initial Dedifferentiation in Four Gossypium hirsutum Cultivars that Have Different SE Capability

RNA sequencing (RNA-Seq)-based gene expression analysis is applicable to a wide range of biological purposes in various species. Reverse transcription quantitative PCR (RT-qPCR) is also used to assess target gene expression utilizing stably expressed reference genes as internal control under a given set of conditions. However, investigations of the reference genes for RT-qPCR normalization in the process of somatic embryogenesis (SE) initial dedifferentiation in Gossypium hirsutum are rarely reported. In this study, on the basis of our previous transcriptome data of three different induction stages during SE initial dedifferentiation process in four G. hirsutum cultivars that have different SE capability, 15 candidate genes were selected during SE initial dedifferentiation process, and their expression stability was evaluated by geNorm, NormFinder, and BestKeeper. The results indicated that the two genes of endonuclease 4 (ENDO4) and 18S ribosomal RNA (18S rRNA) showed stable expression in the four different G. hirsutum cultivars, endowing them to be appropriate reference genes during three induction stages in the four cotton cultivars. In addition, the stability and reliability of the two reference genes of ENDO4 and 18S rRNA were further verified by comparing the expressions of auxin-responsive protein 22 (AUX22) and ethylene-responsive transcription factor 17 (ERF17) between RT-qPCR results and the RNA-seq data, which showed strong positive correlation coefficient (R2 = 0.8396–0.9984), validating again the steady expression of ENDO4 and 18S rRNA as the reliable reference genes. Our results provide effective reference genes for RT-qPCR normalization during SE process in different G. hirsutum cultivars.

Targeting autophagy in thyroid cancers

Thyroid cancer is one of the most common endocrine malignancies. Although the prognosis for the majority of thyroid cancers is relatively good, patients with metastatic, radioiodine-refractory or anaplastic thyroid cancers have an unfavorable outcome. With the gradual understanding of the oncogenic events in thyroid cancers, molecularly targeted therapy using tyrosine kinase inhibitors (TKIs) is greatly changing the therapeutic landscape of radioiodine-refractory differentiated thyroid cancers (RR-DTCs), but intrinsic and acquired drug resistance, as well as adverse effects, may limit their clinical efficacy and use. In this setting, development of synergistic treatment options is of clinical significance, which may enhance the therapeutic effect of current TKIs and further overcome the resultant drug resistance. Autophagy is a critical cellular process involved not only in protecting cells and organisms from stressors but also in the maintenance and development of various kinds of cancers. Substantial studies have explored the complex role of autophagy in thyroid cancers. Specifically, autophagy plays important roles in mediating the drug resistance of small-molecular therapeutics, in regulating the dedifferentiation process of thyroid cancers and also in affecting the treatment outcome of radioiodine therapy. Exploring how autophagy intertwines in the development and dedifferentiation process of thyroid cancers is essential, which will enable a more profound understanding of the physiopathology of thyroid cancers. More importantly, these advances may fuel future development of autophagy-targeted therapeutic strategies for patients with thyroid cancers. Herein, we summarize the most recent evidence uncovering the role of autophagy in thyroid cancers and highlight future research perspectives in this regard.