Hepatitis B virus X protein and TGF-ß: partners in the carcinogenic journey of hepatocellular carcinoma.

Hepatitis B infection is substantially associated with the development of liver cancer globally, with the prevalence of hepatocellular carcinoma (HCC) cases exceeding 50%. Hepatitis B virus (HBV) encodes the Hepatitis B virus X (HBx) protein, a pleiotropic regulatory protein necessary for the transcription of the HBV covalently closed circular DNA (cccDNA) microchromosome. In previous studies, HBV-associated HCC was revealed to be affected by HBx in multiple signaling pathways, resulting in genetic mutations and epigenetic modifications in proto-oncogenes and tumor suppressor genes. In addition, transforming growth factor-ß (TGF-ß) has dichotomous potentials at various phases of malignancy as it is a crucial signaling pathway that regulates multiple cellular and physiological processes. In early HCC, TGF-ß has a significant antitumor effect, whereas in advanced HCC, it promotes malignant progression. TGF-ß interacts with the HBx protein in HCC, regulating the pathogenesis of HCC. This review summarizes the respective and combined functions of HBx and TGB-ß in HCC occurrence and development.

NDRG1 acts as an oncogene in triple-negative breast cancer and its loss sensitizes cells to mitochondrial iron chelation.

Multiple studies indicate that iron chelators enhance their anti-cancer properties by inducing NDRG1, a known tumor and metastasis suppressor. However, the exact role of NDRG1 remains controversial, as newer studies have shown that NDRG1 can also act as an oncogene. Our group recently introduced mitochondrially targeted iron chelators deferoxamine (mitoDFO) and deferasirox (mitoDFX) as effective anti-cancer agents. In this study, we evaluated the ability of these modified chelators to induce NDRG1 and the role of NDRG1 in breast cancer. We demonstrated that both compounds specifically increase NDRG1 without inducing other NDRG family members. We have documented that the effect of mitochondrially targeted chelators is at least partially mediated by GSK3α/ß, leading to phosphorylation of NDRG1 at Thr346 and to a lesser extent on Ser330. Loss of NDRG1 increases cell death induced by mitoDFX. Notably, MDA-MB-231 cells lacking NDRG1 exhibit reduced extracellular acidification rate and grow slower than parental cells, while the opposite is true for ER+ MCF7 cells. Moreover, overexpression of full-length NDRG1 and the N-terminally truncated isoform (59112) significantly reduced sensitivity towards mitoDFX in ER+ cells. Furthermore, cells overexpressing full-length NDRG1 exhibited a significantly accelerated tumor formation, while its N-terminally truncated isoforms showed significantly impaired capacity to form tumors. Thus, overexpression of full-length NDRG1 promotes tumor growth in highly aggressive triple-negative breast cancer.

KRIT1 in Vascular Biology and Beyond.

KRIT1 is a 75 kDa scaffolding protein which regulates endothelial cell phenotype by limiting the response to inflammatory stimuli and maintaining a quiescent and stable endothelial barrier. Loss of function mutations in KRIT1 lead to the development of cerebral cavernous malformations (CCM), a disease marked by the formation of abnormal blood vessels which exhibit a loss of barrier function, increased endothelial proliferation, and altered gene expression. While many advances have been made in our understanding of how KRIT1, and the functionally related proteins CCM2 and PDCD10, contribute to the regulation of blood vessels and the vascular barrier, some important open questions remain. In addition, KRIT1 is widely expressed and KRIT1 and the other CCM proteins have been shown to play important roles in non-endothelial cell types and tissues, which may or may not be related to their role as pathogenic originators of CCM. In this review, we discuss some of the unsettled questions regarding the role of KRIT1 in vascular physiology and discuss recent advances that suggest this ubiquitously expressed protein may have a role beyond the endothelial cell.

Comparative Assessment of miR-185-5p and miR-191-5p Expression: From Normal Endometrium to High-Grade Endometrial Cancer.

Endometrial cancer (EC) is a significant cause of cancer-related deaths in women. MicroRNAs (miRs) play a role in cancer development, acting as oncogenes or tumor suppressors. This study evaluated the diagnostic potential of hsa-miR-185-5p and hsa-miR-191-5p in EC and their correlation with clinical and histopathological features. A cross-sectional study analyzed formalin-fixed, paraffin-embedded tissue samples from 59 patients: 18 with EC, 21 with endometrial hyperplasia (EH), 17 with normal endometrium (NE), and 3 with endometrial polyps (EPs). Quantitative reverse transcription-polymerase chain reaction and TaqMan probes were used for miR expression analysis. The Shapiro-Wilk test was used to analyze the normal distribution of the data. Subsequently, parametric or non-parametric tests were used to evaluate the associations between the expression levels of each miR and clinical parameters. Both miRs were underexpressed in some precursor and malignant lesions compared to certain NE subtypes and benign lesions. Specifically, hsa-miR-185-5p showed underexpression in grade 3 EC compared to some NE and EH subtypes (FC: -57.9 to -8.5, p < 0.05), and hsa-miR-191-5p was underexpressed in EH and EC compared to secretory endometrium and EPs (FC: -4.2 to -32.8, p < 0.05). SETD1B, TJP1, and MSI1 were common predicted target genes. In conclusion, hsa-miR-185-5p and hsa-miR-191-5p are underexpressed in EC tissues, correlating with histopathological grades, highlighting their potential as diagnostic biomarkers and their role as tumor suppressors in EC.

Immunohistochemical Expression of Ki-67 and p53 and Their Prognostic Role in Ameloblastoma: A Longitudinal Study.

Objectives: Ameloblastoma, comprising approximately 11% of all odontogenic tumors, is a locally aggressive tumor with a high recurrence rate. This study aimed to assess the immunohistochemical expression of Ki-67 and p53 and their association with clinical and pathological factors among patients with ameloblastoma. Methods: Retrospective follow-up data of patients histologically confirmed with ameloblastoma at Makerere College of Health Sciences in Kampala, Uganda from January 2012 to December 2018 were retrieved. Factors associated with Ki-67 and p53 immunohistochemical expression were determined using one-way one-way analysis of variance. Chi-square and Fisher's exact statistical tests were used to assess factors associated with recurrence. A two-tailed p < 0.05 was considered statistically significant. Results: A total of 40 patients confirmed histologically with ameloblastoma were included in the analysis. The majority (62.5%) of cases were of the conventional type of ameloblastoma. The expressions of Ki-67 and p53 were 52.5% and 85.0%, respectively. Recurrence was found in 47.5% of patients and it was associated with conventional histological type (p=0.042), segmental resection (p < 0.001), tumor size (p < 0.001), and high p53 expression (p=0.041). Conclusions: Almost half the cases in this study had recurrence. The immunohistochemical expression of p53 was significantly higher than that of Ki-67.

Biological and prognostic significance of NDRG2 downregulation in oral squamous cell carcinoma.

OBJECTIVE: Downregulation of N-myc downstream-regulated gene 2 (NDRG2), a tumor suppressor gene, has been associated with poor clinical outcomes in various cancers. However, the prognostic significance of NDRG2 in oral squamous cell carcinoma (OSCC) remains unknown. This study aimed to evaluate the prognostic value of NDRG2 downregulation in OSCC and to elucidate the mechanism by which NDRG2 is downregulated and the biological role of NDRG2 in tumor progression. METHODS: Immunohistochemical and in silico analyses of NDRG2 expression were performed, and the correlation between NDRG2 expression and clinicopathological data was analyzed. The effect of NDRG2 knockdown on the biological behavior of OSCC cells was investigated and the effect of 5-aza-2'-deoxycytidine (5-aza-dC) on NDRG2 expression was determined. RESULTS: NDRG2 expression was significantly downregulated and DNA hypermethylation of NDRG2 was frequently found in head and neck SCC, including OSCC. Low NDRG2 expression was significantly correlated with adverse clinicopathological features and worse survival in OSCC. NDRG2 knockdown could enhance the oncogenic properties of OSCC cells. NDRG2 mRNA levels in OSCC cells could be restored by 5-aza-dC. CONCLUSION: Downregulation of NDRG2 promotes tumor progression and predicts poor prognosis in OSCC. Therefore, restoration of NDRG2 expression may be a potential therapeutic strategy in OSCC.

ITM2A inhibits the progression of bladder cancer by downregulating the phosphorylation of STAT3.

Bladder cancer stands as one of the prevalent malignancies in urological clinics, highlighting the pressing need to uncover prognostic or therapeutic avenues. ITM2A, a transmembrane protein, has been identified as a suppressor in tumor progression recently. Our study underscored a significant correlation between low ITM2A expression in bladder cancer tissues and high tumor grade, AJCC stage, and poor overall survival time. Additionally, our findings demonstrated that reinstating ITM2A expression impeded cell proliferation, migration, and invasion, while conversely, its suppression enhanced these malignant behaviors. Furthermore, we elucidated that ITM2A could suppress malignant phenotypes of bladder cancer cells via inhibiting activation of the STAT3 induced by IL-6. In conclusion, our research unveiled the mechanistic role of ITM2A in inhibiting tumor progression, shedding light on its potential as a prognostic predictor and therapeutic target in bladder cancer management.

Involvement of N4BP2L1, PLEKHA4, and BEGAIN genes in breast cancer and muscle cell development.

Patients with breast cancer show altered expression of genes within the pectoralis major skeletal muscle cells of the breast. Through analyses of The Cancer Genome Atlas (TCGA)-breast cancer (BRCA), we identified three previously uncharacterized putative novel tumor suppressor genes expressed in normal muscle cells, whose expression was downregulated in breast tumors. We found that NEDD4 binding protein 2-like 1 (N4BP2L1), pleckstrin homology domain-containing family A member 4 (PLEKHA4), and brain-enriched guanylate kinase-associated protein (BEGAIN) that are normally highly expressed in breast myoepithelial cells and smooth muscle cells were significantly downregulated in breast tumor tissues of a cohort of 50 patients with this cancer. Our data revealed that the low expression of PLEKHA4 in patients with menopause below 50 years correlated with a higher risk of breast cancer. Moreover, we identified N4BP2L1 and BEGAIN as potential biomarkers of HER2-positive breast cancer. Furthermore, low BEGAIN expression in breast cancer patients with blood fat, heart problems, and diabetes correlated with a higher risk of this cancer. In addition, protein and RNA expression analysis of TCGA-BRCA revealed N4BP2L1 as a promising diagnostic protein biomarker in breast cancer. In addition, the in silico data of scRNA-seq showed high expression of these genes in several cell types of normal breast tissue, including breast myoepithelial cells and smooth muscle cells. Thus, our results suggest their possible tumor-suppressive function in breast cancer and muscle development.

Crosstalk between circBMI1 and miR-338-5p/ID4 inhibits AML progression.

BMI1 Polycomb Ring Finger Proto-Oncogene (BMI1) is involved in the pathogenesis of different cancers, including acute myeloid leukemia (AML). However, the role of the circular RNA of BMI1 (circBMI1) has not been studied. Our study aimed to investigate the role and mechanism of circBMI1 in AML. circBMI1 was significantly decreased in bone marrow mononuclear cells aspirated from patients with AML. Receiver operating characteristic curve analysis showed that circBMI1 could distinguish patients with AML from controls. By overexpressing and knocking down circBMI1 in HL-60 cells, we found that circBMI1 inhibited cell proliferation, promoted apoptosis, and increased chemotherapeutic drug sensitivity in AML. Experiments using severe combined immune-deficient mice and circBMI1 transgenic mice showed that mice with circBMI1 overexpression had lower white blood cell counts, which suggested less severe AML invasion. RNA immunoprecipitation and dual-luciferase reporter assay revealed binding sites among circBMI1, miR-338-5p, and inhibitor of DNA binding 4 (ID4). Rescue experiments proved that circBMI1 inhibited AML progression by binding to miR-338-5p, which affected the expression of ID4. By coculturing exosomes extracted from circBMI1-HL-60 and small interfering circBMI1-HL-60 cells with HL-60 cells, we found that exosomes from circBMI1-HL-60 cells showed tumor suppressive effects, namely inhibiting HL-60 proliferation, promoting apoptosis, and increasing chemotherapeutic drug sensitivity. Exosomes from small interfering circBMI1-HL-60 cells showed the opposite effects. circBMI1 may act as an exosome-dependent tumor inhibitor. circBMI1, a potential biomarker for clinical diagnosis, acts as a tumor suppressor in AML by regulating miR-338-5p/ID4 and might affect the pathogenesis of AML by exosome secretion.

Long-term follow-up of efficacy and safety of selinexor maintenance treatment in patients with TP53wt advanced or recurrent endometrial cancer: A subgroup analysis of the ENGOT-EN5/GOG-3055/SIENDO study.

OBJECTIVE: To report long-term efficacy and safety of selinexor maintenance therapy in adults with TP53 wild-type (TP53wt) stage IV or recurrent endometrial cancer (EC) who achieved partial remission (PR) or complete remission (CR) following chemotherapy. METHODS: Analysis of the prespecified, exploratory subgroup of patients with TP53wt EC from the phase 3 SIENDO study was performed. Progression-free survival (PFS) benefit in patients with TP53wt EC and across other patient subgroups were exploratory endpoints. Safety and tolerability were also assessed. RESULTS: Of the 263 patients enrolled in the SIENDO trial, 113 patients had TP53wt EC; 70/113 (61.9%) had TP53wt/proficient mismatch repair (pMMR) EC, and 29/113 (25.7%) had TP53wt/deficient mismatch repair (dMMR) EC. As of April 1, 2024, the median PFS (mPFS) for TP53wt patients who received selinexor compared with placebo was 28.4 versus 5.2 months (36.8-month follow-up, HR 0.44; 95% CI 0.27-0.73). A benefit in mPFS was seen with selinexor versus placebo regardless of MMR status (patients with TP53wt/pMMR EC: 39.5 vs 4.9 months, HR 0.36; 95% CI 0.19-0.71; patients with TP53wt/dMMR EC: 13.1 vs 3.7 months, HR 0.49; 95% CI 0.18-1.34). Selinexor treatment was generally manageable, with no new safety signals identified. CONCLUSION: In the phase 3 SIENDO study, selinexor maintenance therapy showed a promising efficacy signal and a manageable safety profile in the prespecified subgroup of patients with TP53wt EC who achieved a PR or CR following chemotherapy. These results are being further evaluated in an ongoing randomized phase 3 trial (NCT05611931).

Potential involvement of KANK1 haploinsufficiency in centrosome aberrations.

KANK1 was found as a tumor suppressor gene based on frequent deletions in renal cell carcinoma and the inhibitory activity of tumor cell proliferation. Previously, we reported that knockdown of KANK1 induced centrosomal amplification, leading to abnormal cell division, through the hyperactivation of RhoA small GTPase. Here, we investigated the loss of KANK1 function by performing CRISPR/Cas9-based genome editing to knockout the gene. After several rounds of genome editing, however, there were no cell lines with complete loss of KANK1, and the less the wild-type KANK1 dosage, the greater the number of cells with abnormal numbers of centrosomes and rates of cell-doubling and apoptosis, suggesting the involvement of KANK1 haploinsufficiency in centrosome aberrations. The rescue of KANK1-knockdown cells with a KANK1-expressing plasmid restored the rates of cells exhibiting centrosomal amplification to the control level. RNA-sequencing analysis of the cells with reduced dosages of functional KANK1 revealed potential involvement of other cell proliferation-related genes, such as EGR1, MDGA2, and BMP3, which have been reported to show haploinsufficiency when they function. When EGR1 protein expression was reduced by siRNA technology, the number of cells exhibiting centrosomal amplification increased, along with the reduction of KANK1 protein expression, suggesting their functional relationship. Thus, KANK1 haploinsufficiency may contribute to centrosome aberrations through the network of haploinsufficiency-related genes.

Acquired cystic disease associated renal cell carcinoma: A clinicopathologic and molecular study of 31 tumors.

Acquired cystic disease associated renal cell carcinomas (ACD-RCC) are rare and their molecular and histopathological characteristics are still being explored. We therefore investigated the clinicopathologic and molecular characteristics of 31 tumors. The patients were predominantly male (n = 30), with tumors mainly left-sided (n = 17), unifocal (n = 19), and unilateral (n = 29) and a mean tumor size of 25 mm (range, 3-65 mm). Microscopically, several histologic patterns were present, including pure classic sieve-like (n = 4), and varied proportions of mixed classic sieve-like with papillary (n = 23), tubulocystic (n = 9), compact tubular (n = 4) and solid (n = 1) patterns. Calcium-oxalate crystals were seen in all tumors. Molecular analysis of 9 tumors using next generation sequencing showed alterations in SMARCB1 in 3 tumors (1 with frameshift deletion and 2 with copy number loss in chromosome 22 involving SMARCB1 region), however, INI1 stain was retained in all. Nonrecurrent genetic alterations in SETD2, NF1, NOTCH4, BRCA2 and CANT1 genes were also seen. Additionally, MTOR p.Pro351Ser was identified in one tumor. Copy number analysis showed gains in chromosome 16 (n = 5), 17 (n = 2) and 8 (n = 2) as well as loss in chromosome 22 (n = 2). In summary, ACD-RCC is a recognized subtype of kidney tumors, with several histological architectural patterns. Our molecular data identifies genetic alterations in chromatin modifying genes (SMARCB1 and SETD2), which may suggest a role of such genes in ACD-RCC development.

[Retracted] MicroRNA­336 directly targets Sox­2 in osteosarcoma to inhibit tumorigenesis.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that certain of the Transwell cell migration and invasion assay data in Fig. 3C and D, and the tumour images shown in Fig. 4A were strikingly similar to data appearing in different form in other articles written by different authors at different research institutes, which had already been published. In addition, certain of the data panels shown in Fig. 3C were overlapping, such that the data from the same original source had been selected to represent the results from allegedly differently performed experiments. Owing to the fact that the contentious data in the above article had already been published prior to its submission to Molecular Medicine Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 15: 4217­4224, 2017; DOI: 10.3892/mmr.2017.6493].

P53 Gene as a Promising Biomarker and Potential Target for the Early Diagnosis of Reproductive Cancers.

One of the crucial aspects of cancer research is diagnosis with specificity and accuracy. Early cancer detection mostly helps make appropriate decisions regarding treatment and metastasis. The well-studied transcription factor tumor suppressor protein p53 is essential for maintaining genetic integrity. p53 is a key tumor suppressor that recognizes the carcinogenic biological pathways and eradicates them by apoptosis. A wide range of carcinomas, especially gynecological such as ovarian, cervical, and endometrial cancers, frequently undergo TP53 gene mutations. This study evaluates the potential of the p53 gene as a biological marker for the diagnosis of reproductive system neoplasms. Immunohistochemistry of p53 is rapid, easy to accomplish, cost-effective, and preferred by pathologists as a surrogate for the analysis of TP53 mutation. Thus, this review lays a groundwork for future efforts to develop techniques using p53 for the early diagnosis of cancer.

Molecular insights and clinical implications for the tumor suppressor role of SCFFBXW7 E3 ubiquitin ligase.

FBXW7 is one of the most well-characterized F-box proteins, serving as substrate receptor subunit of SKP1-CUL1-F-box (SCF) E3 ligase complexes. SCFFBXW7 is responsible for the degradation of various oncogenic proteins such as cyclin E, c-MYC, c-JUN, NOTCH, and MCL1. Therefore, FBXW7 functions largely as a major tumor suppressor. In keeping with this notion, FBXW7 gene mutations or downregulations have been found and reported in many types of malignant tumors, such as endometrial, colorectal, lung, and breast cancers, which facilitate the proliferation, invasion, migration, and drug resistance of cancer cells. Therefore, it is critical to review newly identified FBXW7 regulation and tumor suppressor function under physiological and pathological conditions to develop effective strategies for the treatment of FBXW7-altered cancers. Since a growing body of evidence has revealed the tumor-suppressive activity and role of FBXW7, here, we updated FBXW7 upstream and downstream signaling including FBXW7 ubiquitin substrates, the multi-level FBXW7 regulatory mechanisms, and dysregulation of FBXW7 in cancer, and discussed promising cancer therapies targeting FBXW7 regulators and downstream effectors, to provide a comprehensive picture of FBXW7 and facilitate the study in this field.

RARRES1 identified by comprehensive bioinformatic analysis and experimental validation as a promising biomarker in Skin Cutaneous Melanoma.

Skin cutaneous melanoma (SKCM) is a highly malignant form of skin cancer, known for its unfavorable prognosis and elevated mortality rate. RARRES1, a gene responsive to retinoic acid receptors, displays varied functions in various cancer types. However, the specific role and underlying mechanisms of RARRES1 in SKCM are still unclear. GSE15605 was utilized to analyze the expression of RARRES1 in SKCM. Subsequently, the TCGA and GEO databases were employed to investigate the relationships between RARRES1 and clinicopathological parameters, as well as the prognostic implications and diagnostic efficacy of RARRES1 in SKCM. GO, KEGG, and GSEA analyses were conducted to explore the potential functions of RARRES1. Furthermore, the associations between RARRES1 and immune infiltration were examined. Genomic alterations and promoter methylation levels of RARRES1 in SKCM were assessed using cBioPortal, UALCAN, and the GEO database. Finally, RARRES1 expression in SKCM was validated through immunohistochemistry, and its functional role in SKCM progression was elucidated via in vivo and in vitro experiments. We found that RARRES1 was downregulated in SKCM compared with normal tissues, and this low expression was associated with worse clinicopathological features and poor prognosis of SKCM. The diagnostic efficacy of RARRES1, as determined by ROC analysis, was 0.732. Through GO, KEGG, and GSEA enrichment analysis, we identified 30 correlated genes and pathways that were mainly enriched in the tumor immune microenvironment, proliferation, apoptosis, and autophagy. Additionally, RARRES1 expression was found to be positively related to the infiltration of various immune cells in SKCM, particularly macrophages and T helper cells, among others. Analysis of genomic alterations and promoter methylation revealed that shallow deletion and hypermethylation of the RARRES1 promoter could lead to reduced RARRES1 expression. IHC validation confirmed the downregulation of RARRES1 in SKCM. Moreover, overexpression of RARRES1 inhibited the proliferation and migration of A375 cells, promoted apoptosis, and inhibited autophagic flux. In the mouse xenograft model, RARRES1 overexpression also suppressed SKCM tumor growth. Collectively, these findings suggest that RARRES1 may function as a suppressor and could potentially serve as a prognostic biomarker and therapeutic target for SKCM.

ECRG2/SPINK7 Tumor Suppressor as Modulator of DNA Damage Response.

Esophageal Cancer-Related Gene 2 (ECRG2), also known as Serine Peptidase Inhibitor Kazal type 7 (SPINK7), is a novel tumor suppressor gene from the SPINK family of genes that exhibits anticancer potential. ECRG2 was originally identified during efforts to discover genes involved in esophageal tumorigenesis. ECRG2 was one of those genes whose expression was absent or reduced in primary human esophageal cancers. Additionally, absent or reduced ECRG2 expression was also noted in several other types of human malignancies. ECRG2 missense mutations were identified in various primary human cancers. It was reported that a cancer-derived ECRG2 mutant (valine to glutamic acid at position 30) failed to induce cell death and caspase activation triggered by DNA-damaging anticancer drugs. Furthermore, ECRG2 suppressed cancer cell proliferation in cultured cells and grafted tumors in animals and inhibited cancer cell migration/invasion and metastasis. ECRG2 also was identified as a negative regulator of Hu-antigen R (HuR), an oncogenic RNA-binding protein that is known to regulate mRNA stability and the expression of transcripts corresponding to many cancer-related genes. ECRG2 function is important also for the regulation of inflammatory responses and the maintenance of epithelial barrier integrity in the esophagus. More recently, ECRG2 was discovered as one of the newest members of the pro-apoptotic transcriptional targets of p53. Two p53-binding sites (BS-1 and BS-2) were found within the proximal region of the ECRG2 gene promoter; the treatment of DNA-damaging agents in cancer cells significantly increased p53 binding to the ECRG2 promoter and triggered a strong ECRG2 promoter induction following DNA damage. Further, the genetic depletion of ECRG2 expression significantly impeded apoptotic cell death induced by DNA damage and wild-type p53 in cancer cells. These findings suggest that the loss of ECRG2 expression, commonly observed in human cancers, could play important roles in conferring anticancer drug resistance in human cancers. Thus, ECRG2 is a novel regulator in DNA damage-induced cell death that may also be a potential target for anticancer therapeutics.

Reduced Malignancy of Super Methotrexate-resistant Osteosarcoma Cells With Dihydrofolate Reductase Amplification Despite Paradoxical Gain of Oncogenic PI3K/AKT/mTOR and c-MYC expression.

BACKGROUND/AIM: Methotrexate (MTX) resistance in osteosarcoma leads to a very poor prognosis. In the present study, in order to further understand the basis and ramifications of MTX resistance in osteosarcoma, we selected an osteosarcoma cell line that has a 5,500-fold-increased MTX IC50 Materials and Methods: The super MTX-resistant 143B osteosarcoma cells (143B-MTXSR) were selected from MTX-sensitive parental human 143B osteosarcoma cells (143B-P) by continuous culture with step-wise increased amounts of MTX. To compare the malignancy of 143B-MTXSR and 143B-P, colony-formation capacity was compared with clonogenic assays on plastic and in soft agar. In addition, tumor growth was compared with orthotopic xenograft mouse models of osteosarcoma. Expression of dihydrofolate reductase (DHFR), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR), and myelocytomatosis oncogene (MYC) was examined with western immunoblotting and compared in 143B-MTXSR and 143B-P cells. RESULTS: 143B-MTXSR had a 5,500-fold increase in the MTX IC50 compared to the parental 143B-P cells. Expression of DHFR was increased 10-fold in 143B-MTXSR compared to 143B-P (p<0.01). 143B-MTXSR cells had reduced colony-formation capacity on plastic (p=0.032) and in soft agar (p<0.01) compared to 143B-P and reduced tumor growth in orthotopic xenograft mouse models (p<0.001). These results demonstrate that 143B-MTXSR had reduced malignancy. 143B-MTXSR also showed an increased expression of PI3K (p<0.01), phosphorylated (activated) AKT (p=0.031), phosphorylated mTOR (p=0.043), and c-MYC (p=0.024) compared to 143B-P. CONCLUSION: The present study demonstrates that the increased expression of DHFR, PI3K/AKT/mTOR and c-MYC appears to be linked to super MTX resistance and, paradoxically, to reduced malignancy. The present results suggest that DHFR may be a powerful tumor suppressor when highly amplified.

[Research Progress on Role of Long Non-Coding RNA in Occurrence and Development of Acute Myeloid Leukemia--Review].

In recent years, the importance of long non-coding RNA (lncRNA) in acute myeloid leukemia (AML) has attracted wide attention. Among them, lncRNAs that play a role in promoting cancer mainly include HOTAIR, UCA1, H19, ITGB2-AS1 and some genes of SNHG family, while in tumor suppression mainly include H22954, NEAT1, SNHG4, LINC01128 , etc. This article reviews the role of lncRNAs in the occurrence and development of AML, as well as those related to AML resistance and prognosis assessment, so as to provide a theoretical basis for the diagnosis and prognosis analysis of AML.

Influence of the interaction between p53 and ZNF568 on mitochondrial oxidative phosphorylation.

The tumor suppressor p53 plays important roles in suppressing the development and progression of cancer by responding to various stress signals. In addition, p53 can regulate the metabolic pathways of cancer cells by regulating energy metabolism and oxidative phosphorylation. Here, we present a mechanism for the interaction between p53 and ZNF568. Initially, we used X-ray crystallography to determine the irregular loop structure of the ZNF568 KRAB domain; this loop plays an important role in the interaction between p53 and ZNF568. In addition, Cryo-EM was used to examine how the p53 DBD and ZNF568 KRAB domains bind together. The function of ZNF568 on p53-mediated mitochondrial respiration was confirmed by measuring glucose consumption and lactate production. These findings show that ZNF568 can reduce p53-mediated mitochondrial respiratory activity by binding to p53 and inhibiting the transcription of SCO2. SIGNIFICANCE: ZNF568 can directly bind to the p53 DBD and transcriptionally regulate the SCO2 gene. SCO2 transcriptional regulation by interaction between ZNF568 and p53 may regulate the balance between mitochondrial respiration and glycolysis.