Outcome-based student assessment enhances academic performance in basic medical laboratory course.

Basic medical laboratory courses (BMLCs) play an important role in medical educational courses helping the student acquire three important skills of surgical operating, collaborative learning, and problem solving. The outcome-based student assessment (OBSA) is a learning evaluation method that establishes specific evaluation points based on performance of students in three aspects: surgical operating, collaborative learning, and problem solving in the BMLC curriculum practices. The purpose of the present randomized controlled trial study is to explore the efficiency of OBSA program in BMLCs. The 233 students attending BMLCs were randomly divided into 2 groups, 118 in the OBSA group and 115 in the control group. We conducted multiple-choice examination questions (MCQs) test and two questionnaires with the method of two-sample t test for statistics. The results of MCQs in total eight BMLC blocks showed that the academic performance of the OBSA group was significantly better than that of the control group (P < 0.05). In addition, the average scores of direct observation of procedural skills (DOPS) and mini-experimental evaluation exercise in OBSA group were significantly higher than those in control group (P < 0.05). The majority of the medical students preferred the OBSA and considered OBSA could effectively improve their surgical operating skills (83.9%), collaborative learning skills (92.1%), and problem-solving skills (91.1%). From the above, OBSA is an effective evaluation method for the implementation of the BMLC curriculum.

Upregulation of mtSSB by interleukin-6 promotes cell growth through mitochondrial biogenesis-mediated telomerase activation in colorectal cancer.

It is now widely accepted that mitochondrial biogenesis is inhibited in most cancer cells. Interestingly, one of the possible exceptions is colorectal cancer (CRC), in which the content of mitochondria has been found to be higher than in normal colon mucosa. However, to date, the causes and effects of this phenomenon are still unclear. In the present study, we systematically investigated the functional role of mitochondrial single-strand DNA binding protein (mtSSB), a key molecule in the regulation of mitochondrial DNA (mtDNA) replication, in the mitochondrial biogenesis and CRC cell growth. Our results demonstrated that mtSSB was frequently upregulated in CRC tissues and that upregulated mtSSB was associated with poor prognosis in CRC patients. Furthermore, overexpression of mtSSB promoted CRC cell growth in vitro by regulating cell proliferation. The in vivo assay confirmed these results, indicating that the forced expression of mtSSB significantly increases the growth capacity of xenograft tumors. Mechanistically, the survival advantage conferred by mtSSB was primarily caused by increased mitochondrial biogenesis and subsequent ROS production, which induced telomerase reverse transcriptase (TERT) expression and telomere elongation via Akt/mTOR pathway in CRC cells. In addition, FOXP1, a member of the forkhead box family, was identified as a new transcription factor for mtSSB. Moreover, our results also demonstrate that proinflammatory IL-6/STAT3 signaling facilitates mtSSB expression and CRC cell proliferation via inducing FOXP1 expression. Collectively, our findings demonstrate that mtSSB induced by inflammation plays a critical role in the regulation of mitochondrial biogenesis, telomerase activation, and subsequent CRC proliferation, providing a strong evidence for mtSSB as drug target in CRC treatment.

Mitochondrial fission promotes cell migration by Ca2+ /CaMKII/ERK/FAK pathway in hepatocellular carcinoma.

BACKGROUND & AIMS: Mitochondrial dynamics of fission and fusion plays critical roles in a diverse range of important cellular functions, and its deregulation has been increasingly implicated in human diseases. Previous studies have shown that increased mitochondrial fission significantly promoted the proliferation of hepatocellular carcinoma (HCC) cells. However, how they influence the migration of tumour cells remained largely unknown. METHODS: In the present study, we further investigated the effect of mitochondrial fission on the migration and metastasis of hepatocellular carcinoma cells. Moreover, the underlying molecular mechanisms and therapeutic application were explored. RESULTS: Our data showed that dynamin-1-like protein expression was strongly increased in distant metastasis of hepatocellular carcinoma when compared to primary hepatocellular carcinoma. In contrast, the mitochondrial fusion protein mitofusin 1 showed an opposite trend. Moreover, the expression of dynamin-1-like protein and mitofusin 1 was significantly associated with the disease-free survival of hepatocellular carcinoma patients. In addition, our data further showed that mitochondrial fission significantly promoted the reprogramming of focal-adhesion dynamics and lamellipodia formation in hepatocellular carcinoma cells mainly by activating typical Ca2+ /CaMKII/ERK/FAK pathway. Importantly, treatment with mitochondrial division inhibitor-1 significantly decreased calcium signalling in hepatocellular carcinoma cells and had a potential treatment effect for hepatocellular carcinoma metastasis in vivo. CONCLUSIONS: Taken together, our findings demonstrate that mitochondrial fission plays a critical role in the regulation of hepatocellular carcinoma cell migration, which provides strong evidence for this process as a drug target in hepatocellular carcinoma metastasis treatment.

An eight-long non-coding RNA signature as a candidate prognostic biomarker for bladder cancer.

Backgroud: Bladder cancer (BLCA) is one of the most fatal types of cancer worldwide. However, there are limited methods for us to provide a prognostic prediction of BLCA patients. Therefore, we aimed at developing a lncRNA signature to improve the prognosis prediction of BLCA. RESULTS: An eight-lncRNA signature was significantly associated with recurrence free survival in BLCA patients from both discovery and validation groups. Furthermore, genes involved in the signature were enriched in extracellular matrix organization pathway. Finally, functional experiments demonstrated that six out of the eight lncRNAs significantly regulated the invasion of BLCA cells. METHOD: A total of 343 BLCA patients from The Cancer Genome Atlas (TCGA) were employed and randomly divided into training (n=172) and validating (n=171) groups. The lncRNA expression profiles of BLCA patients were screened and a risk-score formula were created and validated according to the Cox regression analysis. Next, WGCNA method was employed to cluster genes that highly correlated with the risk scores based on the profiling data of TCGA dataset and transwell assay was also performed to further investigate the role of these lncRNAs. CONCLUSIONS: Our results suggested that the eight-lncRNA signature was a candidate prognostic biomarker for predicting tumor recurrence of patients with BLCA.

Increased mtDNA copy number promotes cancer progression by enhancing mitochondrial oxidative phosphorylation in microsatellite-stable colorectal cancer.

Colorectal cancer is one of the leading causes of cancer death worldwide. According to global genomic status, colorectal cancer can be classified into two main types: microsatellite-stable and microsatellite-instable tumors. Moreover, the two subtypes also exhibit different responses to chemotherapeutic agents through distinctive molecular mechanisms. Recently, mitochondrial DNA depletion has been shown to induce apoptotic resistance in microsatellite-instable colorectal cancer. However, the effects of altered mitochondrial DNA copy number on the progression of microsatellite-stable colorectal cancer, which accounts for the majority of colorectal cancer, remain unclear. In this study, we systematically investigated the functional role of altered mitochondrial DNA copy number in the survival and metastasis of microsatellite-stable colorectal cancer cells. Moreover, the underlying molecular mechanisms were also explored. Our results demonstrated that increased mitochondrial DNA copy number by forced mitochondrial transcription factor A expression significantly facilitated cell proliferation and inhibited apoptosis of microsatellite-stable colorectal cancer cells both in vitro and in vivo. Moreover, we demonstrated that increased mitochondrial DNA copy number enhanced the metastasis of microsatellite-stable colorectal cancer cells. Mechanistically, the survival advantage conferred by increased mitochondrial DNA copy number was caused in large part by elevated mitochondrial oxidative phosphorylation. Furthermore, treatment with oligomycin significantly suppressed the survival and metastasis of microsatellite-stable colorectal cancer cells with increased mitochondrial DNA copy number. Our study provides evidence supporting a possible tumor-promoting role for mitochondrial DNA and uncovers the underlying mechanism, which suggests a potential novel therapeutic target for microsatellite-stable colorectal cancer.

Mitochondrial fission forms a positive feedback loop with cytosolic calcium signaling pathway to promote autophagy in hepatocellular carcinoma cells.

Both mitochondrial morphology and the level of cytosolic calcium [Ca2+]c are actively changed and play critical roles in a number of malignancies. However, whether communications existed between these two processes to ingeniously control the malignant phenotype are far from clear. We investigated the reciprocal regulation between mitochondrial fission and cytosolic calcium signaling in human hepatocellular carcinoma (HCC) cells. Furthermore, the underlying molecular mechanisms and the synergistic effect on autophagy were explored. Our results showed that mitochondrial fission increased the [Ca2+]c and calcium oscillation in HCC cells. We further found that mitochondrial fission-mediated calcium signaling was dependent on ROS-activated NF-κB pathways, which facilitated the expression of STIM1 and subsequent store-operated calciumentry. Additionally, we also demonstrated that increase in [Ca2+]c promoted mitochondrial fission by up-regulating expression of Drp1 and FIS1 via transcription factors NFATC2 and c-Myc, respectively. Moreover, the positive feedback loop significantly promoted HCC cell global autophagy by Ca2+/CAMKK/AMPK pathway. Our data demonstrate a positive feedback loop between mitochondrial fission and cytosolic calcium signaling and their promoting role in autophagy of HCC cells, which provides evidence for this loop as a potential drug target in tumor treatment.

Drp1-mediated mitochondrial fission promotes cell proliferation through crosstalk of p53 and NF-κB pathways in hepatocellular carcinoma.

Mitochondria are highly dynamic and undergo constant fusion and fission that are essential for maintaining physiological functions of cells. Recently, we have reported that increased mitochondrial fission promotes autophagy and apoptosis resistance in hepatocellular carcinoma (HCC) cell through ROS-mediated coordinated regulation of NF-κB and p53 pathways. However, little is known about the roles of mitochondrial dynamics in HCC cell proliferation, another key feature of cancer cells. In this study, we systematically investigated the functional role of mitochondrial fission in the regulation of HCC cell proliferation. Furthermore, the underlying molecular mechanisms were deeply explored. We found that, increased mitochondrial fission by forced expression of Drp1 promoted the proliferation of HCC cells both in vitro and in vivo mainly by facilitating G1/S phase transition of cell cycle. Whereas, Drp1 knockdown or treatment with mitochondrial division inhibitor-1 induced significant G1 phase arrest in HCC cells and reduced tumor growth in the xenotransplantation model. We further demonstrated that the proliferation-promoting role of Drp1-mediated mitochondrial fission was mediated via p53/p21 and NF-κB/cyclins pathways. Moreover, the crosstalk between p53 and NF-κB pathways was proved to be involved in the regulation of mitochondrial fission-mediated cell proliferation. In conclusion, our findings demonstrate that Drp1-mediated mitochondrial fission plays a critical role in the regulation of cell cycle progression and HCC cell proliferation. Thus, targeting Drp1-dependent mitochondrial fission may provide a novel strategy for suppressing tumor growth of HCC.