Diagnosis for Chinese patients with light chain amyloidosis: a scoping review.

BACKGROUND: Amyloid light chain (AL) amyloidosis is the most common systemic amyloidosis. The objective of this scoping review was to map the available literature on the diagnosis of AL amyloidosis in China. MATERIALS AND METHODS: The published academic papers related to the diagnosis of AL amyloidosis were screened from 1 January 2000 to 15 September 2021. Chinese patients who have suspected AL amyloidosis were included. The included studies were categorized into accuracy studies and descriptive studies based on if the studies supplied the diagnostic accuracy data or not. The information on the diagnostic methods reported by included studies was synthesized. RESULTS: Forty-three articles were included for the final scoping review, with 31 belonging to descriptive studies and 12 having information on diagnostic accuracy. Although cardiac involvement was second top in Chinese patients with AL amyloidosis, a cardiac biopsy was rare. Next, we found light chain classification and monoclonal (M-) protein identification were essential methods for the diagnosis of AL amyloidosis in China. In addition, some combined tests (e.g. immunohistochemistry and serum free light chain, immunohistochemistry and immunofixation electrophoresis, and serum free light chain and immunofixation electrophoresis) can increase the sensitivity of the diagnosis. Finally, several adjuvant methods (e.g. Imaging, N-terminal-pro hormone BNP, and brain natriuretic peptide test) were important for AL amyloidosis diagnosis. CONCLUSION: This scoping review details the characteristics and results of the recently published studies on diagnosing AL Amyloidosis in China. Biopsy is the most important method for AL Amyloidosis diagnosis in China. In addition, combined tests and some adjuvant methods played essential roles in the diagnosis. Further research is required to determine an acceptable and feasible diagnostic algorithm after symptom onset. REGISTRATION: INPLASY2022100096KEY MESSAGESThis scoping review details the characteristics and results of the recently published studies on diagnosing Amyloid light chain (AL) Amyloidosis in China.Biopsy is the most important method for AL Amyloidosis diagnosis in China.Combined tests and some adjuvant methods played essential roles in the diagnosis.

m6 A Reader YTHDF1-Targeting Engineered Small Extracellular Vesicles for Gastric Cancer Therapy via Epigenetic and Immune Regulation.

N6 -methyladenosine (m6 A) modulators decide the fate of m6 A-modified transcripts and drive cancer development. RNA interference targeting m6 A modulators promise to be an emerging cancer therapy but is challenging due to its poor tumor targeting and high systematic toxicity. Here engineered small extracellular vesicles (sEVs) with high CD47 expression and cyclic arginine-glycine-aspartic (c(RGDyC)) modification are developed for effective delivery of short interfering RNA against m6 A reader YTH N6-methyladenosine RNA binding protein 1 (YTHDF1) to treat gastric cancer via epigenetic and immune regulation. This nanosystem efficiently depletes YTHDF1 expression and suppresses gastric cancer progression and metastasis through hampering frizzled7 translation and inactivating Wnt/ß-catenin pathway in an m6 A dependent manner. Loss of YTHDF1 mediates overexpression of interferon (IFN)-γ receptor 1 and enhances IFN-γ response, promoting expression of major histocompatibility complex class I on tumor cells to achieve self-presentation of the immunogenic tumor cells to stimulate strong cytotoxic T lymphocytes responses. CD47 expression on the engineered sEVs can competitively bind with signal regulatory protein α to enhance phagocytosis of the tumor cells by tumor-associated macrophages. This versatile nanoplatform provides an efficient and low toxic strategy to inhibit epigenetic regulators and holds great potential in promoting immunotherapy.

METTL3 preferentially enhances non-m6A translation of epigenetic factors and promotes tumourigenesis.

METTL3 encodes the predominant catalytic enzyme to promote m6A methylation in nucleus. Recently, accumulating evidence has shown the expression of METTL3 in cytoplasm, but its function is not fully understood. Here we demonstrated an m6A-independent mechanism for METTL3 to promote tumour progression. In gastric cancer, METTL3 could not only facilitate cancer progression via m6A modification, but also bind to numerous non-m6A-modified mRNAs, suggesting an unexpected role of METTL3. Mechanistically, cytoplasm-anchored METTL3 interacted with PABPC1 to stabilize its association with cap-binding complex eIF4F, which preferentially promoted the translation of epigenetic factors without m6A modification. Clinical investigation showed that cytoplasmic distributed METTL3 was highly correlated with gastric cancer progression, and this finding could be expanded to prostate cancer. Therefore, the cytoplasmic METTL3 enhances the translation of epigenetic mRNAs, thus serving as an oncogenic driver in cancer progression, and METTL3 subcellular distribution can assist diagnosis and predict prognosis for patients with cancer.

YTHDF1 Promotes Gastric Carcinogenesis by Controlling Translation of FZD7.

N6-methyladenosine (m6A) is the most prevalent internal RNA modification in mammals that regulates homeostasis and function of modified RNA transcripts. Here, we aimed to investigate the role of YTH m6A RNA-binding protein 1 (YTHDF1), a key regulator of m6A methylation in gastric cancer tumorigenesis. Multiple bioinformatic analyses of different human cancer databases identified key m6A-associated genetic mutations that regulated gastric tumorigenesis. YTHDF1 was mutated in about 7% of patients with gastric cancer, and high expression of YTHDF1 was associated with more aggressive tumor progression and poor overall survival. Inhibition of YTHDF1 attenuated gastric cancer cell proliferation and tumorigenesis in vitro and in vivo. Mechanistically, YTHDF1 promoted the translation of a key Wnt receptor frizzled7 (FZD7) in an m6A-dependent manner, and mutated YTHDF1 enhanced expression of FZD7, leading to hyperactivation of the Wnt/ß-catenin pathway and promotion of gastric carcinogenesis. Our results demonstrate the oncogenic role of YTHDF1 and its m6A-mediated regulation of Wnt/ß-catenin signaling in gastric cancer, providing a novel approach of targeting such epigenetic regulators in this disease. SIGNIFICANCE: This study provides a rationale for controlling translation of key oncogenic drivers in cancer by manipulating epigenetic regulators, representing a novel and efficient strategy for anticancer treatment. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/10/2651/F1.large.jpg.

The m6A reader YTHDF1 promotes ovarian cancer progression via augmenting EIF3C translation.

N 6-Methyladenosine (m6A) is the most abundant RNA modification in mammal mRNAs and increasing evidence suggests the key roles of m6A in human tumorigenesis. However, whether m6A, especially its 'reader' YTHDF1, targets a gene involving in protein translation and thus affects overall protein production in cancer cells is largely unexplored. Here, using multi-omics analysis for ovarian cancer, we identified a novel mechanism involving EIF3C, a subunit of the protein translation initiation factor EIF3, as the direct target of the YTHDF1. YTHDF1 augments the translation of EIF3C in an m6A-dependent manner by binding to m6A-modified EIF3C mRNA and concomitantly promotes the overall translational output, thereby facilitating tumorigenesis and metastasis of ovarian cancer. YTHDF1 is frequently amplified in ovarian cancer and up-regulation of YTHDF1 is associated with the adverse prognosis of ovarian cancer patients. Furthermore, the protein but not the RNA abundance of EIF3C is increased in ovarian cancer and positively correlates with the protein expression of YTHDF1 in ovarian cancer patients, suggesting modification of EIF3C mRNA is more relevant to its role in cancer. Collectively, we identify the novel YTHDF1-EIF3C axis critical for ovarian cancer progression which can serve as a target to develop therapeutics for cancer treatment.

microRNA arm-imbalance in part from complementary targets mediated decay promotes gastric cancer progression.

Strand-selection is the final step of microRNA biogenesis in which functional mature miRNAs are generated from one or both arms of precursor. The preference of strand-selection is diverse during development and tissue formation, however, its pathological effect is still unknown. Here we find that two miRNA arms from the same precursor, miR-574-5p and miR-574-3p, are inversely expressed and play exactly opposite roles in gastric cancer progression. Higher-5p with lower-3p expression pattern is significantly correlated with higher TNM stages and poor prognosis of gastric cancer patients. The increase of miR-574-5p/-3p ratio, named miR-574 arm-imbalance is partially due to the dynamic expression of their highly complementary targets in gastric carcinogenesis, moreover, the arm-imbalance of miR-574 is in turn involved and further promotes gastric cancer progression. Our results indicate that miR-574 arm-imbalance contribute to gastric cancer progression and re-modification of the miR-574-targets homeostasis may represent a promising strategy for gastric cancer therapy.

The RNA-binding protein QKI5 regulates primary miR-124-1 processing via a distal RNA motif during erythropoiesis.

MicroRNA (miRNA) biogenesis is finely controlled by complex layers of post-transcriptional regulators, including RNA-binding proteins (RBPs). Here, we show that an RBP, QKI5, activates the processing of primary miR-124-1 (pri-124-1) during erythropoiesis. QKI5 recognizes a distal QKI response element and recruits Microprocessor through interaction with DGCR8. Furthermore, the recruited Microprocessor is brought to pri-124-1 stem loops by a spatial RNA-RNA interaction between two complementary sequences. Thus, mutations disrupting their base-pairing affect the strength of QKI5 activation. When erythropoiesis proceeds, the concomitant decrease of QKI5 releases Microprocessor from pri-124-1 and reduces mature miR-124 levels to facilitate erythrocyte maturation. Mechanistically, miR-124 targets TAL1 and c-MYB, two transcription factors involved in normal erythropoiesis. Importantly, this QKI5-mediated regulation also gives rise to a unique miRNA signature, which is required for erythroid differentiation. Taken together, these results demonstrate the pivotal role of QKI5 in primary miRNA processing during erythropoiesis and provide new insights into how a distal element on primary transcripts affects miRNA biogenesis.

[Knockdown of YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) inhibits proliferation and promotes apoptosis in MGC-803 gastric cancer cells].

Objective To investigate the effect of knockdown of YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) on cell proliferation, cell cycle and apoptosis of MGC-803 human gastric cancer cells in vitro. Methods The TCGA database was downloaded from UCSC Cancer Browser and to search for the differential expressions of YTHDF2 mRNA in gastric cancer tissues. Short hairpin RNA (shRNA) targeting YTHDF2 was designed and cloned into lentivirus expression vector pLKO.1. Furthermore, MGC-803 gastric cancer cells were transfected with pLKO.1-shRNA to knockdown the expression of YTHDF2, which was confirmed by the detection of YTHDF2 mRNA and protein expression using real-time quantitative PCR and Western blotting, respectively. Then cell proliferation was observed by CCK-8 assay, and cell cycle and apoptosis were examined by flow cytometry. Results According to the TCGA database, the expression of YTHDF2 mRNA in gastric cancer was significantly higher than that in the normal tissues. MGC-803 stably expressing YTHDF2-shRNA was successfully established. Furthermore, the proliferation capacity of YTHDF2-shRNA-expressing MGC-803 cells was significantly inhibited compared with the controls. Similarly, the percentage of YTHDF2-shRNA-expressing MGC-803 cells in G1 phase increased and in S phase decreased compared with the controls. Meanwhile, apoptosis ratio of YTHDF2-shRNA-expressing MGC-803 cells was significantly higher compared with the control groups. Conclusion Knockdown of YTHDF2 in MGC-803 cells inhibits cell proliferation and promotes apoptosis.

QKI5-mediated alternative splicing of the histone variant macroH2A1 regulates gastric carcinogenesis.

Alternative pre-mRNA splicing is a key mechanism for increasing proteomic diversity and modulating gene expression. Emerging evidence indicated that the splicing program is frequently dysregulated during tumorigenesis. Cancer cells produce protein isoforms that can promote growth and survival. The RNA-binding protein QKI5 is a critical regulator of alternative splicing in expanding lists of primary human tumors and tumor cell lines. However, its biological role and regulatory mechanism are poorly defined in gastric cancer (GC) development and progression. In this study, we demonstrated that the downregulation of QKI5 was associated with pTNM stage and pM state of GC patients. Re-introduction of QKI5 could inhibit GC cell proliferation, migration, and invasion in vitro and in vivo, which might be due to the altered splicing pattern of macroH2A1 pre-mRNA, leading to the accumulation of macroH2A1.1 isoform. Furthermore, QKI5 could inhibit cyclin L1 expression via promoting macroH2A1.1 production. Thus, this study identified a novel regulatory axis involved in gastric tumorigenesis and provided a new strategy for GC therapy.