The gut and brain form the gut-brain axis through bidirectional nervous, endocrine, and immune communications. Changes in one of the organs will affect the other organs. Disorders in the composition and quantity of gut microorganisms can affect both the enteric nervous system and the central nervous system (CNS), thereby indicating the existence of a microbiota-gut-brain axis. Due to the intricate interactions between the gut and the brain, gut symbiotic microorganisms are closely associated with various CNS diseases, such as Parkinson's disease, Alzheimer's disease, schizophrenia, and multiple sclerosis. In this paper, we will review the latest advances of studies on the correlation between gut microorganisms and CNS functions & diseases.

Identification of effective prognostic biomarkers and targets are of crucial importance to the management of estrogen receptor positive (ER+) breast cancer. CCNA2 (also known as CyclinA2) belongs to the highly conserved cyclin family and is significantly overexpressed in various cancer types. In this study, we demonstrated that CCNA2 had significant predictive power in distant metastasis free survival, disease free survival, recurrence free survival and overall survival of ER+ breast cancer patients. We also found that CCNA2 was closely associated with tamoxifen resistance. In addition, gene set enrichment analysis (GSEA) revealed that its expression was positively associated with genes overexpressed in endocrine therapy resistant samples. Finally, though CCNA2-Drug interaction network, we demonstrated the interactions between CCNA2 and several available cancer drugs. Overall, we suggest that CCNA2 is a biomarker for the prognosis of ER+ breast cancer and monitoring of tamoxifen efficacy. It's also a promising target for developing new strategies to prevent or even reverse tamoxifen resistance. Moreover, CCNA2 expression may help monitoring tamoxifen efficacy and directing personalized therapies. Nevertheless, in vivo and in vitro experiments and multi-center randomized controlled clinical trials are still needed before its application in clinical settings.

Chronic infection of Mycoplasma hyorhinis (M. hyorhinis) has been postulated to be associated with several types of cancer, but its effect on patients' survival and host factors mediating its infection remain unclear. Herein, we demonstrated that M. hyorhinis p37 protein expression in gastric cancer tissues predicts poor survival and associates with metastasis. M. hyorhinis infects mammalian cells and promotes gastric cancer cell invasiveness via its membrane protein p37. Synthesized peptide corresponding to the N-terminus of p37 prevents M. hyorhinis infection. Host Annexin A2 (ANXA2) interacts with the N-terminus of p37. In addition, EGFR forms a complex with p37 and ANXA2, and is required for M. hyorhinis-induced phosphorylation and membrane recruitment of ANXA2. M. hyorhinis infection is inhibited by siRNA-mediated knockdown of ANXA2 or EGFR, but is enhanced by expression of ectopic ANXA2 or EGFR. Downstream of ANXA2 and EGFR, the NF-kB pathway is activated and mediates M. hyorhinis-driven cell migration. In conclusion, our study unveils the effect of M. hyorhinis infection on gastric cancer survival and uncovers the mechanisms by which M. hyorhinis infects mammalian cells and promotes cancer cell migration. Cancer Res; 74(20); 5782-94. Ó2014 AACR.

Cisplatin remains to be primary chemotherapeutic drug for gastric cancer patients, especially for advanced stage ones. However, primary or acquired resistance often occurs with the mechanisms being not well understood, which results in relapse of the cancer and poor survival. Herein, we found that HER2 upregulation was associated with cisplatin resistance. We observed that cisplatin-resistant gastric cancer cells underwent a morphological change similar to epithelial-mesenchymal transition (EMT) which is mediated by HER2 overexpression. When specific monoclonal antibody Herceptin, small molecular targeted drug CP724714, or small interfering RNA against HER2 was applied, the EMT-like phenotypic change was dramatically reversed. More importantly, the IC50 and Resistance Index of resistant gastric cancer cells to cisplatin were also decreased by any of these treatments.We demonstrated that expression and amplification of HER2 positively correlated with expression of EMT-related transcription factor Snail in gastric cancer tissues. Furthermore, for the first time, we found that HER2/Snail double positive gastric cancer patients had poorer survival than single positive or double negative counterparts, which provided experimental evidence for the necessity of HER2/Snail double testing in gastric cancer. In conclusion, this study provides some clues of the association of cisplatin resistance with HER2 upregulation-induced EMT in gastric cancer cells.

N-α-Acetyltransferase 10 protein (Naa10p, also called arrest-defective 1), the catalytic subunit of N-acetyltransferase A, is a critical regulator of cell death and proliferation. Naa10p is also shown to regulate cancer metastasis by inhibiting cell motility; however, its role in cancer metastasis is not fully understood. In this study, we found that high expression of Naa10p is positively correlated with the survival of patients with breast cancer, whereas negatively correlated with lymph node metastasis. Naa10p inhibits breast cancer cell migration and invasion in vitro and decreases the xenograft growth and metastasis in nude mice. Microarray screening revealed that Naa10p downregulates inhibitors of differentiation 1 (ID1) expression. Naa10p binds to signal transducer and activator of transcription 5a (STAT5a) and decreases STAT5a-stimulated ID1 expression in an acetyltransferase-independent manner. Moreover, Naa10p antagonizes Janus kinase 2-STAT5a signaling by lowering p65-activated interleukin-1β expression. Our results demonstrate a novel mechanism through which Naa10p inhibits the metastasis of breast cancer cells by targeting STAT5a.

Chemoresistance is a major cause of treatment failure and high mortality in advanced gastric cancer (AGC). Currently, the mechanism of chemoresistance remains unclear, and there is no biomarker to accurately predict the efficacy of chemotherapy. In the present study, we established human gastric cancer (GC) cell lines resistant to 5-fluorouracil (5FU), paclitaxel (TA), or cisplatin (DDP) by gradient drug treatment and generated a novel monoclonal antibody 5B2 targeting heterogeneous nuclear ribonucleoproteins C1/C2 (HNRNPC) overexpressed in chemoresistant GC cells. Overexpressing HNRNPC in GC cells promoted chemoresistance, and knockdown of HNRNPC by small interfering RNA (siRNA) reversed chemoresistance. By utilizing available datasets, we demonstrated that high level of HNRNPC transcript indicated poor overall survival (OS) and free of progression (FP). HNRNPC expression was negatively correlated with OS of GC patients treated with 5FU-based drugs and with time to progression (TTP) of GC patients treated with CF regimen. These data suggest the potential usefulness of HNRNPC as a prognostic and therapeutic marker of GC.

Reg3A overexpression promoted cell growth in pancreatic cancer. SOCS3 is a key target in cancer by inhibiting cell growth and inducing apoptosis. SOCS3 negatively regulated Reg3A-mediated cell growth in pancreatic cancer. SOCS3 methylation act in synergy with Reg3A overexpression to promote pancreatic cancer cell growth.

SummaryChemo-/radiotherapy resistance is the main cause accounting for most treatment failure in colorectal cancer (CRC). Tumor-initiating cells (TICs) are the culprit leading to CRC chemo-/radiotherapy resistance. The underlying regulation mechanism of TICs in CRC remains unclear. Here we discovered that miR-15b expression positively correlated with therapeutic outcome in CRC. Expression of miR-15b in pretreatment biopsy tissue samples predicted tumor regression grade (TRG) in rectal cancer patients after receiving neoadjuvant radiotherapy (nRT). Expression of miR-15b in post-nRT tissue samples was associated with therapeutic outcome. DCLK1 was identified as the direct target gene for miR-15b and its suppression was associated with self-renewal and tumorigenic properties of DCLK1+ TICs. We identified B lymphoma Mo-MLV insertion region l homolog (BMI1) as a downstream target regulated by miR-15b/DCLK1 signaling. Thus, miR-15b may serve as a valuable marker for prognosis and therapeutic outcome prediction. DCLK1 could be a potential therapeutic target to overcome chemo-/radioresistance in CRC.