m6A-modified circFNDC3B inhibits colorectal cancer stemness and metastasis via RNF41-dependent ASB6 degradation.

Colorectal cancer (CRC) is the third most frequently diagnosed cancer with unfavorable clinical outcomes worldwide. circFNDC3B plays as a tumor suppressor in CRC, however, the mechanism of circFNDC3B in CRC remains ambiguous. The stem-like properties of CRC cells were detected by the evaluation of stemness markers, sphere formation assay and flow cytometry. qRT-PCR, FISH, IHC, and western blotting assessed the expression and localization of circFNDC3B, RNF41, ASB6, and stemness markers in CRC. The metastatic capabilities of CRC cells were examined by wound healing and Transwell assays, as well as in vivo liver metastasis model. Bioinformatics analysis, RNA immunoprecipitation (RIP), RNA pull-down assay and co-IP were used to detect the associations among circFNDC3B, FXR2, RNF41, and ASB6. Downregulated circFNDC3B was associated with unfavorite survival in CRC patients, and circFNDC3B overexpression suppressed CRC stemness and metastasis. Mechanistically, studies revealed that YTHDC1 facilitated cytoplasmic translocation of m6A-modified circFNDC3B, and circFNDC3B enhanced RNF41 mRNA stability and expression via binding to FXR2. circFNDC3B promoted ASB6 degradation through RNF41-mediated ubiquitination. Functional studies showed that silencing of RNF41 counteracted circFNDC3B-suppressed CRC stemness and metastasis, and ASB6 overexpression reversed circFNDC3B- or RNF41-mediated regulation of CRC stemness and metastasis. Elevated ASB6 was positively correlated with unfavorite survival in CRC patients. In vivo experiments further showed that circFNDC3B or RNF41 overexpression repressed tumor growth, stemness and liver metastasis via modulating ASB6. Taken together, m6A-modified circFNDC3B inhibited CRC stemness and metastasis via RNF41-dependent ASB6 degradation. These findings provide novel insights and important clues for targeted therapeutic strategies of CRC.

Prognostic value of FGFR1 expression and amplification in patients with HNSCC: A systematic review and meta-analysis.

Fibroblast growth factor receptor 1 (FGFR1) has recently been identified as a promising novel therapeutic target and prognostic marker in different types of cancer. In the present study, a meta-analysis was performed to clarify the correlation between FGFR1 and the survival outcomes of head and neck squamous cell carcinoma (HNSCC) patients. PubMed, Embase, and Web of Science were systematically searched for relevant studies in order to explore the prognostic significance of FGFR1 in HNSCC. Hazards ratios (HR) and 95% confidence intervals (CI) were collected to estimate the correlation between overexpression and amplification of FGFR1 and survival outcomes of HNSCC patients. Nine studies including 2708 patients with HNSCC were finally selected for the meta-analysis. The results indicated that FGFR1 predicted poor overall survival (OS) (HR, 1.97; 95% CI, 1.49-2.61, P<0.001) in HNSCC patients. Futhermore, FGFR1 was related to poor OS in human papillomavirus (HPV) negative HNSCC not in HPV positive HNSCC patients. Subgroup analysis stratified by molecular abnormalities, such as overexpression or amplification showed the similar results. The present study demonstrated that HNSCC patients with FGFR1 overexpression and amplification were more likely to exhibit poorer survival.

Subcutaneous versus Intravenous Bortezomib Administration for Multiple Myeloma Patients: a Meta-analysis.

Bortezomib, the first potent therapeutic proteasome inhibitor, has been suggested as a standard care in patients with newly diagnosed and relapsed multiple myeloma (MM). However, evidence bearing on the efficacy and safety of subcutaneous (SC) versus intravenous (IV) administration of bortezomib for MM patients is controversial. Randomised controlled trials (RCTs) and observational studies were enrolled in our meta-analysis to investigate the efficacy and safety of bortezomib via SC vs. IV administration on MM patients. Sixteen trials with a total of2575 patients with MM (SC, n=1191; IV, n=1384) were included in our meta-analysis. There were no significant differences between these two arms regarding overall response rate (ORR), complete response (CR), or very good partial response (VGPR). The pooled RRs for rate of adverse events (AEs), such as thrombocytopenia and bortezomib-induced peripheral neuropathy (BIPN), were 0.79 (95% CI: 0.68-0.92) and 0.63 (95% CI: 0.51-0.79), respectively. Moreover, there was much more largely decreased incidence of grade 3 and higher thrombocytopenia and BIPN in bortezomib SC administration than IV route. In general, alternative SC administration should be considered instead of IV administration in use of bortezomib for patients with MM. Key words: bortezomib; multiple myeloma; meta-analysis; subcutaneous administration.

Gene silencing of the BDNF/TrkB axis in multiple myeloma blocks bone destruction and tumor burden in vitro and in vivo.

Osteolytic bone diseases are a prominent feature of multiple myeloma (MM), resulting from aberrant osteoclastic bone resorption that is uncoupled from osteoblastic bone formation. Myeloma stimulates osteoclastogenesis, which is largely dependent on an increase in receptor activator of NF-κB ligand (RANKL) and a decrease in osteoprotegerin (OPG) within the bone marrow milieu. Recently, brain-derived neurotrophic factor (BDNF) was identified as a MM-derived factor that correlates with increased RANKL levels and contributes to osteolytic bone destruction in myeloma patients. Because tyrosine receptor kinase B (TrkB), the receptor of BDNF, is abundantly expressed in osteoblasts, we sought to evaluate the role of BDNF/TrkB in myeloma-osteoblast interactions and the effect of this pathway on the RANKL/OPG ratio and osteoclastogenesis. Coculture systems constructed with noncontact transwells revealed that, in vitro, MM-derived BDNF increased RANKL and decreased OPG production in osteoblasts in a time- and dose-dependent manner. These effects were completely abolished by a specific small interfering RNA for TrkB. BDNF regulates RANKL/OPG expression in osteoblasts through the TrkB/ERK pathway. To investigate the biological effects of BDNF on myeloma in vivo, a SCID-RPMI8226 mice model was constructed using lentiviral short hairpin RNA-transfected RPMI8226 cells. In this system, stable knockdown of BDNF in MM cells significantly restored the RANKL/OPG homostasis, inhibited osteolytic bone destruction and reduced angiogenesis and tumor burden. Our studies provide further support for the potential osteoclastogenic effects of BDNF, which mediates stroma-myeloma interactions to disrupt the balance of RANKL/OPG expression, ultimately increasing osteoclastogenesis in MM.

miR-15a and miR-16 affect the angiogenesis of multiple myeloma by targeting VEGF.

Deregulated microRNAs (miRNAs) and their roles in cancer development have attracted much attention. Two miRNAs, miR-15a and miR-16, which act as putative tumor suppressor by targeting the oncogene BCL2, have been implicated in cell cycle, apoptosis and proliferation. In this study, we investigated the possible role of miR-15a/16 in the angiogenesis of multiple myeloma (MM). Using a stem-loop quantitative reverse transcription-PCR, we analyzed miR-15a/16 expressions in bone marrow samples from newly diagnosed MM patients and a panel of MM cell lines. miRNA transfection, western blotting analysis and assay of luciferase activity were used to examine whether vascular endothelial growth factor (VEGF) is the target of miR-15a/16. The functional roles of miR-15a/16 on tumorigenesis and angiogenesis were examined by in vitro angiogenesis models and in vivo tumor xenograft model. We showed that miR-15a and miR-16 were significantly underexpressed in primary MM cells as well as in MM cell lines. The aberrant expression of miR-15a/16 was detected especially in advanced stage MM. In human MM cell lines and normal plasma cells, expression of miR-15a/16 inversely correlated with the expression of VEGF-A. Western blotting combined with the luciferase reporter assay demonstrated that VEGF-A was a direct target of miR-15a/16. Ectopic overexpression of miR-15a/16 led to decreased pro-angiogenic activity of MM cells. Finally, infection of lentivirus-miR-15a or lentivirus-miR-16 resulted in significant inhibition of tumor growth and angiogenesis in nude mice. This study suggest that miR-15a/16 could play a role in the tumorigenesis of MM at least in part by modulation of angiogenesis through targeting VEGF-A.

Inhibition of BDNF in multiple myeloma blocks osteoclastogenesis via down-regulated stroma-derived RANKL expression both in vitro and in vivo.

Brain-derived neurotrophic factor (BDNF) was recently identified as a factor produced by multiple myeloma (MM) cells, which may contribute to bone resorption and disease progression in MM, though the molecular mechanism of this process is not well understood. The purpose of this study was to test the effect of BDNF on bone disease and growth of MM cells both in vitro and in vivo. Co- and triple-culture systems were implemented. The in vitro results demonstrate that BDNF augmented receptor activator of nuclear factor kappa B ligand (RANKL) expression in human bone marrow stromal cells, thus contributing to osteoclast formation. To further clarify the effect of BDNF on myeloma bone disease in vivo, ARH-77 cells were stably transfected with an antisense construct to BDNF (AS-ARH) or empty vector (EV-ARH) to test their capacity to induce MM bone disease in SCID-rab mice. Mice treated with AS-ARH cells were preserved, exhibited no radiologically identifiable lytic lesions and, unlike the controls treated with EV-ARH cells, lived longer and showed reduced tumor burden. Consistently, bones harboring AS-ARH cells showed marked reductions of RANKL expression and osteoclast density compared to the controls harboring EV-ARH cells. These results provide further support for the potential osteoclastogenic effects of BDNF, which may mediate stromal-MM cell interactions to upregulate RANKL secretion, in myeloma bone diseases.

Brain-derived neurotrophic factor is a potential osteoclast stimulating factor in multiple myeloma.

Multiple myeloma (MM) is characterized by accumulation of monoclonal plasma cells in the bone marrow and progression of lytic bone lesions. The mechanisms of enhanced bone resorption in patients with myeloma are not fully defined. We have previously identified the role of brain-derived neurotrophic factor (BDNF) in proliferation and migration of MM cells. In our study, we investigated whether BDNF was possibly involved in MM cell-induced osteolysis. We showed that BDNF was elevated in MM patients and the bone marrow plasma levels of BDNF positively correlated with extent of bone disease. In osteoclast formation assay, bone marrow plasma from patients with MM increased osteoclast formation and the effect was significantly blocked by neutralizing antibody to BDNF, suggesting a critical role for BDNF in osteoclast activation. Furthermore, the direct effects of recombinant BDNF on osteoclast formation and bone resorption support the potential role of BDNF in the MM bone disease. BDNF receptor TrkB was expressed by human osteoclast precursors and a Trk inhibitor K252a markedly inhibited osteoclast formation stimulated with BDNF, demonstrating that BDNF used TrkB for its effects on osteoclast. Finally, bone marrow plasma BDNF level positively correlated with macrophage inflammatory protein-1α and receptor activator of nuclear factor-κB ligand, two major osteoclast stimulatory factors in MM. These results support an important role for BDNF in the development of myeloma bone disease.

Clinical significance of chromosomal abnormalities detected by interphase fluorescence in situ hybridization in newly diagnosed multiple myeloma patients.

BACKGROUND: Chromosome 13q14 deletion (del13q14), chromosome 1q21 gain (amp1q21) and chromosome 17p13 deletion (del17p13) are the most frequent chromosomal aberrations in multiple myeloma (MM). They play an important role in prognosis. The aim of this study was to investigate the clinical significance of the chromosomal changes in Chinese MM patients. METHODS: Interphase fluorescence in situ hybridization (FISH) on bone marrow (BM) cells was performed in 72 enrolled MM patients. Relationships between chromosomal abnormalities and clinical features, response to therapies and prognosis were analyzed. RESULTS: As a result of interphase FISH, 77.8% (56/72) patients had chromosome changes. The incidences of each probe were RB1 51.4% (37/72), D13S319 47.2% (34/72), 1q21 45.8% (33/72) and p53 22.2% (12/72). Osteolytic lesion, BM plasma cells index, serum calcium and serum M component were significantly correlated to del13q14. BM plasma cells and hemoglobin were correlated to amp1q21. Serum lactate dehydrogenase (LDH) was correlated with del17p13. Patients with del13q14 treated with bortezomib had a notably higher overall response rate than the patients treated with traditional chemotherapies (93% vs. 65%, P = 0.048). Patients carrying amp1q21 or/and del17p13 did not achieve satisfactory response to bortezomib. The median progression-free survival (PFS) for patients with amp1q21 was 5 months and patients without amp1q21 got 9-month PFS (P = 0.001). The median PFS for patients with del13q14 was 5 months (vs. 8 months, P = 0.026). The median PFS for patients with del17p13 was 3 months (vs. 8 months, P = 0.002). Patients with ß(2)-microglobulin > 5.5 mg/L also had a worse outcome, whose median PFS was 5 months (vs. 8 months, P = 0.016). CONCLUSIONS: The prevalence of chromosomal abnormalities of MM patients was similar in Chinese and Caucasian people. Genetic changes were associated with patients' responses to therapies and prognosis.