Daxing Xie

DAB2IP regulates cancer stem cell phenotypes through modulating stem cell factor receptor and ZEB1.

Cancer stem cell (CSC), the primary source of cancer-initiating population, is involved in cancer recurrence and drug-resistant phenotypes. This study demonstrates that the loss of DAB2IP, a novel Ras-GTPase activating protein frequently found in many cancer types, is associated with CSC properties. Mechanistically, DAB2IP is able to suppress stem cell factor receptor (c-kit or CD117) gene expression by interacting with a newly identified silencer in the c-kit gene. Moreover, DAB2IP is able to inhibit c-kit-PI3K-Akt-mTOR signaling pathway that increases c-myc protein to activate ZEB1 gene expression leading to the elevated CSC phenotypes. An inverse correlation between CD117 or ZEB1 and DAB2IP is also found in clinical specimens. Similarly, Elevated expression of ZEB1 and CD117 are found in the prostate basal cell population of DAB2IP knockout mice. Our study reveals that DAB2IP has a critical role in modulating CSC properties via CD117-mediated ZEB1 signaling pathway.

DAB2IP in cancer.

DOC-2/DAB2 is a member of the disable gene family that features tumor-inhibiting activity. The DOC-2/DAB2 interactive protein, DAB2IP, is a new member of the Ras GTPase-activating protein family. It interacts directly with DAB2 and has distinct cellular functions such as modulating different signal cascades associated with cell proliferation, survival, apoptosis and metastasis. Recently, DAB2IP has been found significantly down regulated in multiple types of cancer. The aberrant alteration of DAB2IP in cancer is caused by a variety of mechanisms, including the aberrant promoter methylation, histone deacetylation, and others. Reduced expression of DAB2IP in neoplasm may indicate a poor prognosis of many malignant cancers. Moreover, DAB2IP stands for a promising direction for developing targeted therapies due to its capacity to inhibit tumor cell growth in vitro and in vivo. Here, we summarize the present understanding of the tumor suppressive role of DAB2IP in cancer progression; the mechanisms underlying the dysregulation of DAB2IP; the gene functional mechanism and the prospects of DAB2IP in the future cancer research.

Mesogastrium: a fifth route of metastasis in gastric cancer?

Radical gastrectomy for gastric cancer with D2 lymph node dissection has been widely applied in advanced gastric cancer. It is believed that such surgery should extremely sweep away local-regional tumor tissues and cancer cells and thoroughly prevent tumor recurrence in situ. However, for most patients with advanced gastric cancer, tumor local-regional recurrence has been proven unavoidable. This study has found that isolated cancer cells, separate from the primary lesion and lymph nodes, existed in the mesogastrium of resected gastric cancer specimens, leading to the hypothesis that these cancer cells may have infiltrated the mesogastrium through a fifth metastasis route (here named Metastasis V) which is distinct from the other four classic metastasis routes, and cannot be resected by conventional radical gastrectomy with D2 lymph node dissection. Local-regional recurrence might be closely associated with these cancer cells in the mesogastrium, and therefore, complete mesogastrium excision (CME) should be imperative and become the third radical principle for radical gastrectomy.

Detection and Characterization of Metastatic Cancer Cells in the Mesogastrium of Gastric Cancer Patients.

Gastric cancer is the second leading cause of cancer death worldwide. Here, we propose a novel type of tumor metastasis designated as Metastasis V in gastric cancer. Metastasis V is defined as the appearance of cancer cells in the mesogastrium with perigastric adipose tissue. To detect its incidence and characterize its clinic pathological features, large cross sectional tissue analysis of mesogastrium from 74 patients were used. Metastasis V was detected in 1 of 40 (2.5%) patients with early gastric cancer, 8 of 34 (24%) patients with advanced gastric cancer. The mean distance of Metastasis V from gastric wall was approximately 2.6 cm. Metastasis V was closely associated with tumor invasion depth, along with a number of positive lymph node metastasis. The prognosis of patients with Metastasis V was significantly (P<0.05) worse than those with tumor cell-free mesogastrium. These findings indicate that by using whole-sectional analysis, Metastasis V can be detected in the mesogastrium of gastric cancer patients, and also suggests that it may be a risk factor for patient survival after radical surgery.

Absence of DAB2IP promotes cancer stem cell like signatures and indicates poor survival outcome in colorectal cancer

Metastasis is a critical factor for the high mortality of colorectal cancer (CRC), but its mechanism is not completely understood. Epithelial-mesenchymal transition (EMT) is thought to play a key role in metastasis and also increases the cancer stem cell (CSC) feature that facilitates metastatic colonization. In this study, we investigated the biological roles of DAB2IP regulating EMT and stem cell–like features in human CRC. We demonstrate that DAB2IP suppresses NF-κB-mediated EMT and CSC features in CRC cells. In DAB2IP knockout mice, we discovered the hyperplasia in colonic epithelium which aberrantly represents the mesenchymal feature and NF-κB pathway activation. In clinic CRC tissue, we also reveal that reduced DAB2IP can enrich the CD133+ subpopulation. DAB2IP expression was inversely correlated with tumor differentiation and metastasis, and patients with lower DAB2IP expression had shorter overall survival time. Taken together, our study demonstrates that DAB2IP inhibits NF-κB-inducing EMT and CSC to suppress the CRC progression, and also suggests that DAB2IP is a beneficial prediction factor for CRC patient prognosis.

An Optimal Approach for Laparoscopic D3 Lymphadenectomy Plus Complete Mesocolic Excision (D3+CME) for Right-Sided Colon Cancer.

It is common knowledge that high ligation of blood vessels at the D3 level and complete mesocolic excision (CME) are two critical points of right hemicolectomy for right colon cancer (RCC). 1–5 To date, a safe strategy for completing these two procedures under laparoscopic surgery has not been extensively described. The authors provide a video to demonstrate laparoscopic right hemicolectomy (D3xa0+xa0CME) with an optimal mesentery-defined approach. By identifying three “tri-junctions,” this approach facilitates dissection of the entire mesocolon along the embryologic planes as far centrally as possible and enables the high tie of feeding vessels at bifurcation. The authors propose that this approach is safe, decreases blood loss, and is a secure method for right colon cancer intervention. Between June 2014 and June 2015, the study recruited 36 patients with informed consent, and these patients underwent laparoscopic D3+CME for right colon cancer by a single surgeon. All the participants provided informed written consent to participate in the study. This study was approved by the Tongji Hospital Ethics Committee. The patients’ demographics, oncologic charac- teristics, postoperative outcomes within 30xa0days, and follow-up data were collected. The perioperative outcomes included blood lost, number of retrieved lymph nodes, postoperative hospital length of stay, and morbidity. The postoperative 30-day morbidity included cardiovascular, pulmonary, and urinary complications, as well as wound infection, anastomotic leakage, and postoperative ileus. The complications were diagnosed and categorized based on relevant clinical manifestations. For this procedure, all patients are placed in the Trendelenburg position, with five trocars inserted. Carbon dioxide (CO2) is inflated through the intraumbilical trocar, maintaining steady intraabdominal pressure. The operating surgeon stands between the patient’s legs, with the camera holder on the left and the assistant on the right. The operation table will be rotated left side up to redistribute the small bowels. The standard surgical procedures shown in the video are as follows. First, the surgeon identifies the first “tri-junction” (TJ1) in the ileocolic area (TJ1 is the fusion point of the mesocolon, the visceral peritoneum, and the intestinal mesentery). The surgeon then incises along the fusion fascia and separates the loose connective tissues with an ultrasonically activated device. Mobilization is continued to the origins of the ileocolic vessels, which are clipped and cut. The posterior mesocolic fascia is bluntly separated from the inferior mesentery bed, which is formed by duodenum, Gerota’s fascia, and nearby structures. The second part of duodenum and the head of pancreas are exposed. Next, the surgeon mobilizes along the superior mesentery vein (SMV) and superior mesentery artery (SMA), with blunt dissection of the covering fascia and loose connective tissue to preserve the entire mesocolon completely and as far centrally as possible. Careful dissection is continued until the middle colic vessels (middle colic vein and middle colic artery) are reached. Afterward, the superior right colic vein of Henle’s trunk is exposed and divided at the root. One pack of gauze is inserted beneath the mobilized mesocolon. Second, the surgeon divides the greater omentum. Entrance to the omental bursa is established after the second “tri-junction” (TJ2) is identified (TJ2 is the fusion point of the transverse mesocolon, the mesogastrium and the greater omentum). The fusion plane is bluntly separated between the transverse mesocolon (TM) and the right gastroepiploic mesentery (RGEM) until the previously placed gauze is exposed. Finally, the third “tri-junction” (TJ3) is identified (TJ3 is the fusion point of the retroperitoneum, the mesocolon, and the lateral peritoneum) at the inferior attachments of cecum. The ascending colon is freed up with mobilization of the lateral retroperitoneal attachments from the cecum to the hepatic flexture. Special attention should be paid to avoid breaking the fascia renalis. The tumor carrying the colon is exteriorized through an abdominal incision with a wound protector. Continuity of the digestive tract is performed extracorporeally with side-to-side ileotransverse colon anastomosis using a linear stapler. All the treatments follow standardized recovery protocols. This study recruited 20 males and 16 females. The median age was 56.5xa0years, and the median body mass index (BMI) was 22.1xa0kg/m2. Twelve patients had experienced previous abdominal surgery. No intraoperative complications occurred. The tumor was located in the ileocecus of 14 patients and in the hepatic flexture of 22 patients (Supplemental Tablexa01). The median number of retrieved lymph nodes was 20 (interquartile range [IQR], 14.8–27 (Supplemental Tablexa02). The median volume of blood lost was 5xa0ml (IQR 5–10xa0ml). The median postoperative hospital stay was 10xa0days (IQR 9–12.3xa0days). One patient received treatments from the intensive care unit (ICU). One patient underwent reoperation for incision dehiscence. Seven patients had a postoperative complication diagnosed within 30xa0days (Supplemental Tablexa03). The median follow-up period was 12xa0months (IQR 3–20) months. All the patients received adjuvant chemotherapy, with no case of recurrence (Supplemental Tablexa04). An optimal mesentery-defined approach for laparoscopic D3xa0+xa0CME allows for ligation of feeding vessels at their bifurcation and for CME to be performed simultaneously with technical efficiency. This procedure is safe and strongly practical for advanced right colon cancer intervention.BackgroundIt is common knowledge that high ligation of blood vessels at the D3 level and complete mesocolic excision (CME) are two critical points of right hemicolectomy for right colon cancer (RCC).1–5 To date, a safe strategy for completing these two procedures under laparoscopic surgery has not been extensively described. The authors provide a video to demonstrate laparoscopic right hemicolectomy (D3xa0+xa0CME) with an optimal mesentery-defined approach. By identifying three “tri-junctions,” this approach facilitates dissection of the entire mesocolon along the embryologic planes as far centrally as possible and enables the high tie of feeding vessels at bifurcation. The authors propose that this approach is safe, decreases blood loss, and is a secure method for right colon cancer intervention.MethodsBetween June 2014 and June 2015, the study recruited 36 patients with informed consent, and these patients underwent laparoscopic D3+CME for right colon cancer by a single surgeon. All the participants provided informed written consent to participate in the study. This study was approved by the Tongji Hospital Ethics Committee. The patients’ demographics, oncologic charac- teristics, postoperative outcomes within 30xa0days, and follow-up data were collected. The perioperative outcomes included blood lost, number of retrieved lymph nodes, postoperative hospital length of stay, and morbidity. The postoperative 30-day morbidity included cardiovascular, pulmonary, and urinary complications, as well as wound infection, anastomotic leakage, and postoperative ileus. The complications were diagnosed and categorized based on relevant clinical manifestations. For this procedure, all patients are placed in the Trendelenburg position, with five trocars inserted. Carbon dioxide (CO2) is inflated through the intraumbilical trocar, maintaining steady intraabdominal pressure. The operating surgeon stands between the patient’s legs, with the camera holder on the left and the assistant on the right. The operation table will be rotated left side up to redistribute the small bowels. The standard surgical procedures shown in the video are as follows. First, the surgeon identifies the first “tri-junction” (TJ1) in the ileocolic area (TJ1 is the fusion point of the mesocolon, the visceral peritoneum, and the intestinal mesentery). The surgeon then incises along the fusion fascia and separates the loose connective tissues with an ultrasonically activated device. Mobilization is continued to the origins of the ileocolic vessels, which are clipped and cut. The posterior mesocolic fascia is bluntly separated from the inferior mesentery bed, which is formed by duodenum, Gerota’s fascia, and nearby structures. The second part of duodenum and the head of pancreas are exposed. Next, the surgeon mobilizes along the superior mesentery vein (SMV) and superior mesentery artery (SMA), with blunt dissection of the covering fascia and loose connective tissue to preserve the entire mesocolon completely and as far centrally as possible. Careful dissection is continued until the middle colic vessels (middle colic vein and middle colic artery) are reached. Afterward, the superior right colic vein of Henle’s trunk is exposed and divided at the root. One pack of gauze is inserted beneath the mobilized mesocolon. Second, the surgeon divides the greater omentum. Entrance to the omental bursa is established after the second “tri-junction” (TJ2) is identified (TJ2 is the fusion point of the transverse mesocolon, the mesogastrium and the greater omentum). The fusion plane is bluntly separated between the transverse mesocolon (TM) and the right gastroepiploic mesentery (RGEM) until the previously placed gauze is exposed. Finally, the third “tri-junction” (TJ3) is identified (TJ3 is the fusion point of the retroperitoneum, the mesocolon, and the lateral peritoneum) at the inferior attachments of cecum. The ascending colon is freed up with mobilization of the lateral retroperitoneal attachments from the cecum to the hepatic flexture. Special attention should be paid to avoid breaking the fascia renalis. The tumor carrying the colon is exteriorized through an abdominal incision with a wound protector. Continuity of the digestive tract is performed extracorporeally with side-to-side ileotransverse colon anastomosis using a linear stapler. All the treatments follow standardized recovery protocols.ResultsThis study recruited 20 males and 16 females. The median age was 56.5xa0years, and the median body mass index (BMI) was 22.1xa0kg/m2. Twelve patients had experienced previous abdominal surgery. No intraoperative complications occurred. The tumor was located in the ileocecus of 14 patients and in the hepatic flexture of 22 patients (Supplemental Tablexa01). The median number of retrieved lymph nodes was 20 (interquartile range [IQR], 14.8–27 (Supplemental Tablexa02). The median volume of blood lost was 5xa0ml (IQR 5–10xa0ml). The median postoperative hospital stay was 10xa0days (IQR 9–12.3xa0days). One patient received treatments from the intensive care unit (ICU). One patient underwent reoperation for incision dehiscence. Seven patients had a postoperative complication diagnosed within 30xa0days (Supplemental Tablexa03). The median follow-up period was 12xa0months (IQR 3–20) months. All the patients received adjuvant chemotherapy, with no case of recurrence (Supplemental Tablexa04).ConclusionAn optimal mesentery-defined approach for laparoscopic D3xa0+xa0CME allows for ligation of feeding vessels at their bifurcation and for CME to be performed simultaneously with technical efficiency. This procedure is safe and strongly practical for advanced right colon cancer intervention.

Short-term outcomes of laparoscopic D2 lymphadenectomy with complete mesogastrium excision for advanced gastric cancer.

BackgroundD2 lymphadenectomy has been widely accepted as a standard procedure of surgical treatment for local advanced gastric cancer [1, 2]. However, neither the dissection boundary nor the extent of the excision for perigastric soft tissues has been described [3–7]. Our previous researches demonstrate the existence of disseminated cancer cells in the mesogastrium [8, 9] and present an understandable mesogastrium model for gastrectomy [10]. Hence, the D2 lymphadenectomy plus complete mesogastrium excision (D2xa0+xa0CME) is firstly proposed in this study, aiming to assess the safety, feasibility and corresponding short-term surgical outcomes.MethodsAll of these patients underwent laparoscopy assisted D2xa0+xa0CME radical gastrectomy with a curative R0 resection, and all the operations were performed by Prof. Jianping Gong, chief of GI surgery of Tongji Hospital, Huazhong University of Science and Technology. All participants provided informed written consent to participate in the study. This study was approved by the Tongji Hospital Ethics Committee. The standard surgical procedures in the video are described as follows. Dissect along the gastrocolic ligament and then toward the left colic flexture with special made gauze. Bluntly separate the adipose tissues to find fascia plane. Expose along the plane toward the splenic inferior polar area. Precede to the origins of left gastroepiploic vessels (LGEVs), clip and cut. All the mobilized adipose tissues in this area are defined as left gastroepiploic mesentery (LGEM) [10]. Next, turn to infra-pyloric area. Dissect the fascia plane between right gastroepiploic mesentery (RGEM) and transverse mesocolon. Turn to the pancreas head, remove the covering adipose tissues, identify the superior mesentery vein and expose the origins of right gastroepiploic vessels (RGEVs). Clip and cut. All the surrounding mobilized adipose tissues are defined as RGEM [10]. Move to the superior boarder of pancreas with the stomach reflected cephalad, incise the serosa and bluntly mobilize through the plane with gauze. Turn to the common hepatic artery (CHA), remove the adherent adipose tissue. Expose the root of left gastric vein, clip and cut. Dissect the thick sheath of left gastric artery, expose at the root, trip clip and cut. All mobilized lateral adipose tissues and dorsal parts are defined as left gastric mesentery (LGM) [10]. Toward right, dissect follow the CHA and hepatic portal vein (HPV). Next, move toward the left side of LGM and dissect along the splenic artery until reaching the posterior gastric wall. Move to the anterior area of stomach and divide the lesser omentum. Clean up the adipose tissue and nerves along the lesser curvature up to the gastroesophageal junction. Expose and cut the right gastric vessels (RGVs) where the mobilized adipose tissues are defined as right gastric mesentery (RGM) [10]. Reconstruction of the alimentary tract was done by extracorporeal anastomosis. Standard recovery protocols were followed in postoperative treatments.ResultsFifty-four patients between September 2014 and March 2015 have been recruited with informed consent and underwent laparoscopic D2xa0+xa0CME by a single surgeon. The mean number of retrieved regional lymph nodes was 35.04xa0±xa010.70 (range 14–55). The mean volume of blood loss was 12.44xa0±xa022.89xa0ml (range 5–100). The mean laparoscopic surgery time was 127.82xa0±xa017.63xa0min (range 110–165). The mean hospitalization time was 11.09xa0± 4.28xa0days (range 8–28). No operative complication was observed during the hospitalization.ConclusionThe anatomical boundary of mesogastrium is well described and dissected within D2xa0+xa0CME surgical process. It proves to be safely feasible and repeatable with less blood lost, qualified lymph nodes retrieval results and other improved short-term surgical outcomes in advanced gastric cancer. Meanwhile, potential disseminated cancer cells fall into the mesogastrium can be eradicated by D2xa0+xa0CME.

Proximal segmentation of the dorsal mesogastrium reveals new anatomical implications for laparoscopic surgery

Generally, the gold standard of radical surgery for gastrointestinal (GI) tumors is en bloc resection of primary lesions and their related tissues. For gastric cancer, the ideal surgical treatment should be D2 radical gastrectomy plus complete mesogastrium excision. Complete mesogastrium excision is rarely done or mentioned since little is known about the mesogastrium and its presence is still with controversy. Topographically, the “mesogastrium” refers to a peri-gastric structure composed of “fascia propria”, enveloping lymph nodes, blood vessels and adipose tissues, which by connecting to the stomach, suspends from the posterior abdominal wall. In this study, by employing video laparoscopy, a number of proximal segments of dorsal mesogastrium were found being extensively scattered around the pancreas. The structure of the mesogastrium was further identified intraoperatively and then confirmed both grossly and histologically after the operation. Our results demonstrated the existence of mesogastrium (gastric mesentery) and its architecture. We suggest for the first time a “Table model” to describe the relationship between the stomach and gastric mesenteries enveloped by fascia propria, which might provide an improvement in the surgical methods for excision of gastric cancer.

Prospective randomized controlled trial to compare laparoscopic distal gastrectomy (D2 lymphadenectomy plus complete mesogastrium excision, D2 + CME) with conventional D2 lymphadenectomy for locally advanced gastric adenocarcinoma: study protocol for a randomized controlled trial

BackgroundAlthough radical gastrectomy with D2 lymph node dissection has become the standard surgical approach for locally advanced gastric cancer, patients still have a poor prognosis after operation. Previously, we proposed laparoscopic distal gastrectomy (D2 lymphadenectomy plus complete mesogastrium excision [D2u2009+u2009CME]) as an optimized surgical procedure for locally advanced gastric cancer. By dissection along the boundary of the mesogastrium, D2u2009+u2009CME resected proximal segments of the dorsal mesogastrium completely with less blood loss, and it improved the short-term surgical outcome. However, the oncologic therapeutic effect of D2u2009+u2009CME has not yet been confirmed.Methods/designA single-center, prospective, parallel-group, randomized controlled trial of laparoscopic distal gastrectomy with D2u2009+u2009CME versus conventional D2 was conducted for patients with locally advanced gastric cancer at Tongji Hospital, Wuhan, China. In total, 336 patients who met the following eligibly criteria were included and were randomized to receive either the D2u2009+u2009CME or D2 procedure: (1) pathologically proven adenocarcinoma; (2) 18 to 75xa0years old; cT2–4, N0–3, M0 at preoperative evaluation; (3) expected curative resection via laparoscopic distal gastrectomy; (4) no history of other cancer, chemotherapy, or radiotherapy; (5) no history of upper abdominal operation; and (6) perioperative American Society of Anesthesiologists class I, II, or III. The primary endpoint is 3xa0years of disease-free survival. The secondary endpoints are overall survival, recurrence pattern, mortality, morbidity, postoperative recovery course, and other parameters.DiscussionPrevious studies have demonstrated the safety and feasibility of D2u2009+u2009CME for locally advanced gastric cancer; however, there is still a lack of evidence to support its therapeutic effect. Thus, we performed this randomized trial to investigate whether D2u2009+u2009CME can improve oncologic outcomes of patients with locally advanced gastric cancer. The findings from this trial may potentially optimize the surgical procedure and may improve the prognosis of patients with locally advanced gastric cancer.Trial registrationClinicalTrials.gov, NCT01978444. Registered on October 31, 2013.

Hippo component YAP promotes focal adhesion and tumour aggressiveness via transcriptionally activating THBS1/FAK signalling in breast cancer

BackgroundFocal adhesion plays an essential role in tumour invasiveness and metastasis. Hippo component YAP has been widely reported to be involved in many aspects of tumour biology. However, its role in focal adhesion regulation in breast cancer remains unexplored.MethodsTissue microarray was used to evaluate YAP expression in clinical breast cancer specimens by immunohistochemical staining. Cell migration and invasion abilities were measured by Transwell assay. A cell adhesion assay was used to measure the ability of cell adhesion to gelatin. The focal adhesion was visualized through immunofluorescence. Phosphorylated FAK and other proteins were detected by Western blot analysis. Gene expression profiling was used to screen differently expressed genes, and gene ontology enrichment was performed using DAVID software. The gene mRNA levels were measured by quantitative real-time PCR. The activity of the THBS1-promoter was evaluated by dual luciferase assay. Chromatin immunoprecipitation (ChIP) was used to verify whether YAP could bind to the THBS1-promoter region. The prediction of potential protein-interaction was performed with the String program. The ChIP sequence data of TEAD was obtained from the ENCODE database and analysed via the ChIP-seek tool. The gene expression dataset (GSE30480) of purified tumour cells from primary breast tumour tissues and metastatic lymph nodes was used in the gene set enrichment analysis. Prognostic analysis of the TCGA dataset was performed by the SurvExpress program. Gene expression correlation of the TCGA dataset was analysed via R2: Genomics Analysis and Visualization Platform.ResultsOur study provides evidence that YAP acts as a promoter of focal adhesion and tumour invasiveness via regulating FAK phosphorylation in breast cancer. Further experiments reveal that YAP could induce FAK phosphorylation through a TEAD-dependent manner. Using gene expression profiling and bioinformatics analysis, we identify the FAK upstream gene, thrombospondin 1, as a direct transcriptional target of YAP-TEAD. Silencing THBS1 could reverse the YAP-induced FAK activation and focal adhesion.ConclusionOur results unveil a new signal axis, YAP/THBS1/FAK, in the modulation of cell adhesion and invasiveness, and provides new insights into the crosstalk between Hippo signalling and focal adhesion.