Jiabo Di

GOLPH3 predicts survival of colorectal cancer patients treated with 5-fluorouracil-based adjuvant chemotherapy

BackgroundGolgi phosphoprotein 3 (GOLPH3) has been validated as a potent oncogene involved in the progression of many types of solid tumors, and its overexpression is associated with poor clinical outcome in many cancers. However, it is still unknown the association of GOLPH3 expression with the prognosis of colorectal cancer (CRC) patients who received 5-fluorouracil (5-FU)-based adjuvant chemotherapy.MethodsThe expression of GOLPH3 was determined by qRT-PCR and immunohistochemistry in colorectal tissues from CRC patients treated with 5-FU based adjuvant chemotherapy after surgery. The association of GOLPH3 with clinicopathologic features and prognosis was analysed. The effects of GOLPH3 on 5-FU sensitivity were examined in CRC cell lines.ResultsGOLPH3 expression was elevated in CRC tissues compared with matched adjacent noncancerous tissues. Kaplan-Meier survival curves indicated that high GOLPH3 expression was significantly associated with prolonged disease-free survival (DFS, P = 0.002) and overall survival (OS, P = 0.011) in patients who received 5-FU-based adjuvant chemotherapy. Moreover, multivariate analysis showed that GOLPH3 expression was an independent prognostic factor for DFS in CRC patients treated with 5-FU-based chemotherapy (HR, 0.468; 95%CI, 0.222-0.987; P = 0.046). In vitro, overexpression of GOLPH3 facilitated the 5-FU chemosensitivity in CRC cells; while siRNA-mediated knockdown of GOLPH3 reduced the sensitivity of CRC cells to 5-FU-induced apoptosis.ConclusionsOur results suggest that GOLPH3 is associated with prognosis in CRC patients treated with postoperative 5-FU-based adjuvant chemotherapy, and may serve as a potential indicator to predict 5-FU chemosensitivity.

Downregulated USP3 mRNA functions as a competitive endogenous RNA of SMAD4 by sponging miR-224 and promotes metastasis in colorectal cancer

Increasing evidence shows that competitive endogenous RNAs (ceRNAs) can affect the expression of other transcripts by sequestering common microRNAs (miRNAs), and participate in tumourigenesis. As a potent tumour suppressor in colorectal cancer (CRC), SMAD4 is regulated by many miRNAs. However, the regulation of SMAD4 by ceRNAs has never been examined. In the present study, we found that USP3 modulated SMAD4 expression in a miRNA dependent, and protein-coding gene independent manner. USP3 and SMAD4 were directly targeted by miR-224, and overexpression of the USP3 3′UTR could inhibit metastasis caused by the loss of USP3. The correlation of USP3, SMAD4 and miR-224 expression was further verified in CRC specimens. Additionally, the loss of USP3 was associated with distal metastasis and a poor prognosis. Altogether, our study demonstrates USP3 as a bona fide SMAD4 ceRNA. The results from this study may provide new insights into the prevention and treatment of CRC.

Evaluation of immune responses of gastric cancer patients treated by laparoscopic and open gastrectomy

Laparoscopic surgery has been shown to offer more advantages than open surgery for the treatment of gastric cancer. However, the perioperative immune responses after laparoscopic surgery remain largely unexplored. Here, we analyzed the immunity of gastric cancer patients treated by laparoscopy-assisted gastrectomy (LAG) or open gastrectomy (OG) with D2 dissection. Seventy patients were randomized into LAG and OG groups. The operative details and postoperative outcomes of the two groups were compared. The immune factors were measured preoperatively as well as on the first, third, and seventh postoperative days (POD). Our results indicate that there was no significant difference between two groups in clinical characteristics. The profiles of white blood cells, neutrophils, lymphocytes, as well as the lymphocyte subpopulations, including T lymphocytes, B lymphocytes, CD4+ T cells, and CD8+ T cells were similar in the LAG and the OG groups. Only the natural killer cell counts were significantly higher in LAG-treated patients than in OG-treated ones on POD7. Moreover, no statistical differences were found between the two groups with respect to the levels of perioperative cytokines, including IFN-γ, IL-4, IL-6, and TNF-α. However, compared with the OG group, most of the immune factors in the LAG group had trends to return to preoperative levels on POD7. Our study demonstrates that the immune function of LAG-treated patients showed patterns similar to that of OG-treated patients, although larger prospective multicenter trials are needed to further evaluate the immunological status of LAG.

Whole exome sequencing reveals intertumor heterogeneity and distinct genetic origins of sporadic synchronous colorectal cancer

Sporadic synchronous colorectal cancer (CRC) refers to more than one primary tumor detected in a single patient at the time of the first diagnosis without predisposition of cancer development. Given the same genetic and microenvironment they raise, sporadic synchronous CRC is a unique model to study CRC tumorigenesis. We performed whole exome sequencing in 32 fresh frozen tumor lesions from 15 patients with sporadic synchronous CRC to compare their genetic alterations. This approach identified ubiquitously mutated genes in the range from 0.34% to 4.22% and from 0.8% to 7.0% in non‐hypermutated tumors and hypermutated tumors, respectively, in a single patient. We show that both ubiquitously mutated genes and candidate cancer genes from different tumors in the same patient mutated at different sites. Consistently, obvious differences in somatic copy number variations (SCNV) were found in most patients with non‐hypermutated tumor lesions, which had ubiquitous copy number amplification rates ranging from 0% to 8.8% and ubiquitous copy number deletion rates ranging from 0% to 8.2%. Hypermutated lesions were nearly diploid with 0% to 18.8% common copy number aberrations. Accordingly, clonal structures, altered signaling pathways and druggable genes in a single patient with synchronous CRC varied significantly. Taken together, the disparate SCNVs and mutations in synchronous CRC supported the field effect theory of tumorigenesis. Moreover, the intertumor heterogeneity of synchronous CRCs implies that analysis of all tumor lesions from the same patient is necessary for appropriate clinical treatment decisions.

CENPH Inhibits Rapamycin Sensitivity by Regulating GOLPH3-dependent mTOR Signaling Pathway in Colorectal Cancer

Background: Centromere protein H (CENPH) is known as a fundamental component of the active centromere complex, and its overexpression is correlated with poor prognosis in various solid tumors. mTOR inhibitor rapamycin has been shown to possess antitumor activity, as well as prevent intestinal tumorigenesis. However, the prognostic value of CENPH in colorectal cancer (CRC) and the role of CENPH in rapamycin sensitivity remain unknown. Materials and methods: The effect of CENPH on the cell proliferation, clonogenicity, and cell response to rapamycin in CRC were evaluated by MTT and/or colony formation assays. For the underlying mechanisms, the interaction between CENPH and GOLPH3 were detected by co-immunoprecipitation, GST pull-down, and His-tag pull-down assays, as well as the laser scanning confocal microscopy. The status of kinases in mTOR signaling was determined by Western blot. Finally, the clinical significance of CENPH was analyzed using public CRC datasets with CENPH transcripts and clinical information. Results: CENPH inhibited CRC malignant phenotypes, conferred reduced sensitivity to rapamycin, and attenuated both mTORC1 and mTORC2 in mTOR signaling pathway through the interaction with golgi phosphoprotein 3 (GOLPH3), which has been identified as a potential oncogene and modulates the response to rapamycin. Moreover, elevated levels of CENPH were detected in CRC tissues, compared with normal colorectal tissues. High levels of CENPH expression gradually decreased according to CRC tumor stages. Patients with high CENPH expression had favorable survival. Conclusions: Our results suggest that CENPH inhibits rapamycin sensitivity by regulating GOLPH3 dependent mTOR pathway. High CENPH expression is associated with better prognosis in CRC patients. Taken together, CENPH may serve as a potential predictor for rapamycin sensitivity and therapeutic target for CRC patients.

STK25-induced inhibition of aerobic glycolysis via GOLPH3-mTOR pathway suppresses cell proliferation in colorectal cancer

BackgroundSerine/threonine protein kinase 25 (STK25) is critical in regulating whole-body glucose and insulin homeostasis and the accumulation of ectopic lipids. The Warburg effect, also known as aerobic glycolysis, is an essential metabolic characteristic of cancer cells. However, the effects of STK25 on aerobic glycolysis of cancer cells remain unexplored. The aim of this study is to investigate the role of STK25 in colorectal cancer (CRC) and to elucidate the underlying mechanisms.MethodsThe influences of STK25 on the cell proliferation were evaluated by MTT and colony formation assays. The roles of STK25 in aerobic glycolysis were determined by glucose uptake and lactate production assays. The interaction between STK25 and GOLPH3 was detected by co-immunoprecipitation, GST pull-down, and His-tag pull-down assays. Western blot was used to measure the expression of glycolytic genes, and the status of kinases in mTOR pathway. Moreover, a xenograft mouse model was used to investigate the effects of STK25 in vivo. The prognostic significance of STK25 was analyzed using public CRC datasets by a log-rank test.ResultsSTK25 suppressed proliferation, glycolysis and glycolytic gene expression in CRC cells. STK25 interacted with GOLPH3 and mediated glycolysis through GOLPH3-regulated mTOR signaling. Consistent with these observations, silencing of STK25 promoted tumor growth and glycolytic gene expression in an in vivo xenograft mouse model. Moreover, high levels of STK25 correlated with favorable prognosis in patients with CRC.ConclusionsOur results demonstrated that STK25 negatively regulates the proliferation and glycolysis via GOLPH3-dependent mTOR signaling. Accordingly, STK25 could be a potential therapeutic target for the treatment of CRC.

KIF14 promotes cell proliferation via activation of Akt and is directly targeted by miR-200c in colorectal cancer

As a mitotic kinesin, kinesin family member 14 (KIF14) has been reported to serve oncogenic roles in a variety of malignancies; however, its functional role and regulatory mechanisms in colorectal cancer (CRC) remain unclear. In the present study, KIF14 was observed to be markedly overexpressed in CRC, and this upregulation was associated with tumor size and marker of proliferation Ki-67 immunostaining scores. Gain- and loss-of-function experiments were applied to identify the function of KIF14 in CRC progression. In vitro and in vivo assays revealed that KIF14 promoted CRC cell proliferation and accelerated the cell cycle via activation of protein kinase B. In addition, the present study investigated the potential mechanisms underlying KIF14 overexpression in CRC. Bioinformatics analyses and validation experiments, including reverse transcription-quantitative polymerase chain reaction, western blotting and a Dual-Luciferase reporter assay, demonstrated that, in addition to genomic amplification and transcriptional activation, KIF14 was regulated by microRNA (miR)-200c at the post-transcriptional level. Rescue experiments further demonstrated that decreased miR-200c expression could facilitate KIF14 to exert its pro-proliferative role. The expression of miR-200c was negatively correlated with KIF14 in CRC specimens. Collectively, the findings of the present study demonstrated the oncogenic role of KIF14 in colorectal tumorigenesis, and also revealed a complexity of regulatory mechanisms mediating KIF14 overexpression, which may provide insight for developing novel treatments for patients with CRC.

Comparison of EpCAMhighCD44+ cancer stem cells with EpCAMhighCD44− tumor cells in colon cancer by single-cell sequencing

ABSTRACT Cancer stem cells (CSCs) are considered to be responsible for tumorigenesis and cancer relapse. EpCAMhighCD44+ tumor cells are putative colorectal CSCs that express high levels of stem cell genes, while the EpCAMhighCD44− population mostly contains differentiated tumor cells (DTCs). This study aims to determine whether single CSC (EpCAMhighCD44+) and DTC (EpCAMhighCD44−) can be distinguished in terms of somatic copy number alterations (SCNAs). We applied fluorescence-activated cell sorting to isolate the CD45−EpCAMhighCD44+ and CD45−EpCAMhighCD44− populations from two primary colon tumors, on which low-coverage single-cell whole-genome sequencing (WGS) was then performed ∼0.1x depth. We compared the SCNAs of the CSCs and DTCs at single-cell resolution. In total, 47 qualified single cells of the two populations underwent WGS. The single-cell SCNA profiles showed that there were obvious SCNAs in both the CSCs and DTCs of each patient, and each patient had a specific copy number alteration pattern. Hierarchical clustering and correlation analysis both showed that the SCNA profiles of CSCs and DTCs from the same patient had similar SCNA pattern, while there were regional differences in the CSCs and DTCs in certain patient. SCNAs of CSCs in the same patient were highly reproducible. Our data suggest that major SCNAs occurred at an early stage and were inherited steadily. The similarity of ubiquitous SCNAs between the CSCs and DTCs might have arisen from lineage differentiation. CSCs from the same patient had reproducible SCNA profiles, indicating that gain or loss in certain chromosome is required for colon cancer development.

Clinical significance of circulating immune cells in left- and right-sided colon cancer

Background Left-sided and right-sided colon cancers (LCCs and RCCs, respectively) differ in their epidemiology, pathogenesis, genetic and epigenetic alterations, molecular pathways and prognosis. Notably, immune response gene expression profiles have been shown to differ between patients with LCC and patients with RCC. The immune system plays an important role in tumor immunosurveillance, and there is increasing evidence that peripheral blood immune cells have a profound influence on tumor prognosis. This study aimed to determine the clinical significance of circulating immune cells with respect to colon tumor locations. Methods Different types of circulating immune cells were separated and analysed based on their surface markers by flow cytometry. We compared the numbers of dendritic cells (DCs) and T cell subsets in the peripheral blood of 94 patients with RCC or LCC and analysed the proportions of these immune cells in relation to tumor stage, tumor differentiation and lymphatic metastasis. Results We show that at later tumor stages, patients with LCC had higher levels of circulating myeloid DCs (P = 0.049) and plasmacytoid DCs (P = 0.018) than patients with RCC. In poorly differentiated tumors, LCC patients had significantly higher amount of plasmacytoid DCs (P = 0.036), CD4+ memory T (Tm) cells (P = 0.012), CD4+ T cells (P = 0.028), Tm cells (P = 0.014), and regulatory T cells (P = 0.001) than RCC patients. The levels of circulating CD4+ T cells, Tm cells and CD4+ Tm cells were significantly elevated at later stages in patients with LCC or RCC, while these cells decreased in poorly differentiated tumors in patients with RCC. Moreover, CD4+ Tm cell and CD4+ T cell levels are significantly associated with lymph node metastasis in patients with LCC and RCC. Discussion Circulating immune cells were associated with tumor location, tumor stage and tumor differentiation, and can be used to predict lymphatic metastasis in patients with colon cancer. This variation in systemic immunity could contribute to the differential prognosis of patients with colon cancer.

Multi-region and single-cell sequencing reveal variable genomic heterogeneity in rectal cancer

BackgroundColorectal cancer is a heterogeneous group of malignancies with complex molecular subtypes. While colon cancer has been widely investigated, studies on rectal cancer are very limited. Here, we performed multi-region whole-exome sequencing and single-cell whole-genome sequencing to examine the genomic intratumor heterogeneity (ITH) of rectal tumors.MethodsWe sequenced nine tumor regions and 88 single cells from two rectal cancer patients with tumors of the same molecular classification and characterized their mutation profiles and somatic copy number alterations (SCNAs) at the multi-region and the single-cell levels.ResultsA variable extent of genomic heterogeneity was observed between the two patients, and the degree of ITH increased when analyzed on the single-cell level. We found that major SCNAs were early events in cancer development and inherited steadily. Single-cell sequencing revealed mutations and SCNAs which were hidden in bulk sequencing. In summary, we studied the ITH of rectal cancer at regional and single-cell resolution and demonstrated that variable heterogeneity existed in two patients. The mutational scenarios and SCNA profiles of two patients with treatment naïve from the same molecular subtype are quite different.ConclusionsOur results suggest each tumor possesses its own architecture, which may result in different diagnosis, prognosis, and drug responses. Remarkable ITH exists in the two patients we have studied, providing a preliminary impression of ITH in rectal cancer.