Objective To summarize the roles of tumor initiating cells （TICs） and epithelial-mesenchymal transition （EMT） in tumor metastasis and drug resistance. Methods Domestic and international publications online which involving TICs，EMT，and its roles in tumor metastasis and drug resistance in recent years were reviewed. Results TICs were self-renewal cells and had the ability to give rise to more differentiated cell types，and played an important role in tumor metastasis and drug resistance. Various markers had been used to identify TICs，such as CD133，CD44，and so on. EMT was the process by which epithelial cells losed polarity and detach from the epithelial sheet， and acquired a motile mesenchymal phenotype，usually observed in embryo development and wound healing. It also could promote tumor progression and metastasis，and may also be responsible for the ability of tumors to evade the body’s immune response. EMT may be the reasons of TICs that drived tumor metastasis and recurrence. TICs or EMT as a target for treatments may effectively prevent tumor recurrence and improve patient’s survival. Conclusions EMT is probably the mechanism that TICs promote tumor metastasis and drug resistance. More effective target therapies for cancer may be found if we know more about TICs and EMT.
Objective To summarize the status of tumor stem cells investigations in gastrointestinal carcinoma. Methods Domestic and international publications online involving tumor stem cells of gastrointestinal carcinoma in recent years were collected and reviewed. Results There are a small quantity of cancer cells shown some stem cell characteristics. They are named tumor stem cell and play an important role in tumorigenesis, proliferation, metastasis and recurrence. And also, tumor stem cells can resist the effect of antineoplastic drugs and lead to tumor recurrence. These tumor-initiating cells are CD133-positive in the gastrointestinal carcinomas, especially in colorectal cancers. CD133-positive colorectal cancer cells have the abilities of clone, proliferation, differentiation and form metastases. And a high CD133 mRNA content was found in the blood of patients who suffered from bone metastases. Conclusion The characteristics of CD133-positive cancer cell and the mechanisms of stem cell-niche system are the basis of developing better methods to tumor diagnosis and treatment, and provide theoretical basis of new methods, such as targeted therapy.
Objective To summarize the research progress of gastrointestinal stem cells and its role in gastric neoplasms. Methods The literatures related effect of gastrointestinal stem cells niche， gastrointestinal stem cells markers，and the cancer stem cell theory in the gastric neoplasms were retrieved through PubMed， the research progress of gastrointestinal stem cells and cancer stem cells in the gastric neoplasms was explored. Results The cancer stem cell theory arose a decade ago. Gastrointestinal stem cells played a very important role in the gastric neoplasms， which had specific markers and their niches included many kinds of tissue factors. Inflammation could induce gastrointestinal stem cells dysplasia and become cancer stem cells， which promoted the growth， invasion， and metastasis of the gastric neoplasms. Conclusions Gastric cancer stem cells could be one of an effective target in treatment for gastric neoplasms， and it may be provide a new breakthrough in treatment for gastric neoplasms.
ObjectiveTo summarize the role of epithelial-mesenchymal-transition （EMT） in occurrence and development of gastrointestinal cancer. MethodsDomestic and international publications online involving EMT of gastrointestinal cancer in recent years were collected and reviewed. ResultsEMT was a highly conserved process that has been well characterised in embryogenesis. Studies had shown that the aberrant activation of EMT in adult epithelia could promote tumour metastasis by repressing cell adhesion molecules. E-cadherin， one of the epithelial cell markers, maybe involved in the process of the EMT, especially of the Ecadherin transcriptional repressors， these transcriptional repressors significantly increased in the gastrointestinal cancer. Further more， EMT might involve in the process of gastrointestinal cancer stem cells formation. ConclusionsEMT and it’s regulators play a very important role in gastrointestinal cancer， and may provide a newsight into the gastrointestinal cancer. It also can provide a novel clinical targets to treat the gastrointestinal cancer.
Objective To summarize the relationships between chemokines or chemokine receptors, especially CCL19/CCL21-CCR7 and CXCL12-CXCR4 axis and occurrence and development of gastric cancer. Methods Domestic and international publications online involving the relationships between chemokines, chemokine recepotors and gastric cancer in recent years were collected and reviewed. Results By regulating the microenvironment of the growth of gastric cancer, CCL19/CCL21-CCR7 played an important role in lymph node metastasis and CXCL12-CXCR4 axis played a key role in the development of peritoneal carcinomatosis. CCR7 might function as a specific prognostic marker for lymph node metastasis of gastric cancer. Blocking the CXCL12-CXCR4 axis might be useful for the future development of a more effective therapeutic strategy for gastric cancer involved in peritoneal dissemination. Conclusions Chemokines and chemokine receptors promote the evolution of gastric cancer in variable ways, so the mechanisms of which should be comprehended to provide a theoretical basis for the future treatment. As new therapeutic targets, chemokines and chemokine receptors have a prosperity for the clinic evaluation and treatment of gastric cancer.
Objective To investigate the role of vascular endothelial growth factor-C (VEGF-C) and its receptors in the formation of lymphatic vessels and lymphatic metastasis in gastric cancer. Methods By the domestic and overseas literatures review, the expressions of VEGF-C and its receptors in gastric cancer, their role in tumor lymphatic metastasis and prospect in treatment of gastric cancer were summarized.Results There was a significant correlation between VEGF-C and its receptors and the formation of lymphatic vessels and lymphatic metastasis in gastric cancer. VEGF-C high expression might be an early event in lymphatic metastasis and could be considered as an independent predictive factor of lymphaticmicrometastasis. By inhibition of gastric cancer cell from secrete VEGF-C or blockage of the interaction of VEGF-C with VEGFR3, it was possible to inhibit tumor angiogenesis and the invasion and distant spread of cancer cells, thereby decreased mortality and improve survival. ConclusionVEGF-C and its receptors may promote the formation of lymphatic vessels and lymphatic metastasis in gastric cancer. It may be an effective way to gastric cancer for the treatments against VEGF-C and its receptors.
Objective To summarize the role of matrix metalloproteinases (MMPs) in occurrence and development of gastric cancer. Methods Domestic and international publications online involving MMPs of gastric cancer in recent years were collected and reviewed. Results The occurrence and development of gastric cancer was a multi-step and multi-factorial complicated progress, whose etiology and pathogenesis were still unclarified. MMPs were a class of proteolytic enzymes, which played an important role in the proliferation, metastasis, angiogenesis of gastric cancer and apoptosis of tumor cells and their surrounding normal cells by regulating the microenvironment of the growth of tumor. Conclusion MMPs promote the evolution of gastric cancer in variable ways, the mechanisms of which should be comprehended to provide a theoretical basis for the future treatment of gastric cancer.
Objective To study the expressions of Wnt5a, MMP2, and MMP14 in the primary lesions of gastric cancer and the influences on clinicopathologic features. Methods The expressions of Wnt5a, MMP2, and MMP14 in the specimens of 106 patients with gastric cancer and 39 patients from the adjacent normal gastric tissues were detected by immunohistochemical staining, χ2 test and non-parametric test were used to analyze the relationships among them and between them and their influences on the clinicopathologic features. Results Extensive expressions of Wnt5a, MMP2, and MMP14 were demonstrated in the gastric cancer, which were significantly higher than those in the normal gastric tissues respectively (Plt;0.05). Positive expression of Wnt5a was associated with larger tumor diameter, deeper depth of invasion, higher degree of regional lymph node metastasis, later TNM stage, and higher rate of lymph node metastasis (Plt;0.05). In addition, Wnt5a expression was also associated with lymphatic infiltration and vascular infiltration (Plt;0.05). The expressions of MMP2 and MMP14 were associated with lymphatic infiltration, but not with vascular infiltration. Higher expressions of MMP2 and MMP14 were correlated with deeper tumor invasion, higher degree of regional lymph node metastasis, later TNM stage, and higher rate of lymph node metastasis (Plt;0.05). In addition, higher expression of MMP2 possesed greater tumor diameter (Plt;0.05). Spearman rank correlation analysis revealed the positive relation between Wnt5a and MMP2 （rs=0.240, P=0.014）, Wnt5a and MMP14 （rs=0.251, P=0.010）, as well as MMP2 and MMP14 （rs=0.444, P=0.000）. Conclusion Higher expressions of Wnt5a, MMP2, and MMP14 seem to promote invasion and metastasis of gastric cancer, and there are positive relations among their expressions.
ObjectiveTo detect the expressions of CD133 in four gastric cancer cell lines (KATO-Ⅲ, SGC7901, AGS, and MKN-45) and investigate the different biological characteristics of CD133 positive (CD133+) cells and CD133 negative (CD133-) cells in the KATO-Ⅲ cell lines. MethodsThe CD133 gene and protein expressions of four gastric cancer cell lines were evaluated by semiquantitative RT-PCR and Western blot, respectively. CD133+ cells in KATO-Ⅲ cell lines were isolated by magnetic activated cell sorting (MACS) and examined in morphology, growth characteristics, proliferation, and differentiation in vitro. The sensitivity of different concentrations (0.05, 0.10, 0.20, 0.50, and 1.00 mg/ml) 5-fluoropyrimidinedione (5-FU) were contrasted by drug sensitivity testing in vitro (Cell Counting Kit 8-assay) between CD133+ cells and CD133- cells. ResultsThe expressions of CD133 gene and protein in the KATO-Ⅲ cell lines were significantly higher than those in the other three cell lines (Plt;0.05). CD133+ cells produced spheroid colonies in serum-free medium culture and were ber abilities of proliferation and differentiation than those of CD133- cells in vitro. The inhibitor rate of the CD133+ cells at concentration of 0.50 mg/ml was lower than that of CD133- cells (Plt;0.05). ConclusionsCell population with CD133+ in the KATO-Ⅲ cell lines have b ability of cloning, better capability of proliferation and differentiation, as well as anticancer drug resistance to 5-FU. CD133 can be applied as one of surface markers for the detection to gastric cancer initiator cells.
Objective To investigate the clinical meanings of lymphangiogenesis, lymph vessel invasion (LVI) and lymph node (LN) micrometastasis in gastric cancer. Methods The expression of D2-40 in 68 patients with gastric cancer of primary lesion and the expressions of CK20 and (or) CKpan in 791 lymph nodes from 51 cases which were detected by immunohistochemical staining were analyzed, as well as their clinicopathologic profiles. The relationship of lymph vessel density (LVD), LVI and LN micrometastasis with LN metastasis and other clinicopathologic parameters was analyzed respectively. Results Positive rate of LVI with HE (LVI-HE) and D2-40 (LVI-IM) staining was respectively 66.2%(45/68) and 76.5%(52/68), P=0.118. The positive rate of LVI-IM was related to deeper tumor invasion (P=0.044), later stage of TNM (P=0.003) and LN metastasis (P=0.000). Average LVD of 68 cases was (18.19±7.44)/HP. The increment of LVD was significantly associated with LVI-HE positive status （P=0.040）, LVI-IM positive status （P=0.001）, venous invasion （P=0.037）, later stage of TNM （P=0.020） and LN metastasis （P=0.001）. The survival rate of the group sharing ≥15/HP of LVD was significantly lower than that in the group sharing ≤14/HP of LVD in early period of follow-up （P=0.032）. The incidence of nodal involvement in 51 patients was increased from 74.5%(38/51) by HE staining to 88.2%(45/51) by CK (CK20 or CKpan) immunostaining. The detection rate of metastasized LN was increased from 32.0%（253/791） by HE staining to 41.5%（328/791） by CK immunostaining (Plt;0.001). The significant difference of LN micrometastasis detection rate between CK20 (8.7%) and CKpan (12.3%) was also identified (P=0.003). The increased number of LN micrometastasis was related to larger diameter of tumor (P=0.001), higher LVI-HE positive rate (P=0.040), deeper invasion of tumor (P=0.018) and later stage of TNM (P=0.012). Both LN stage and TNM stage were changed according to the detection of LN micrometastasis: Seven patients of N0 should be recognized as N1 (N0→N1)， 6 as N1→N2, 1 as N2→N3. Four patients of stage Ⅰb should be recognized as stage Ⅱ (Ⅰb→Ⅱ)， 4 as Ⅱ→Ⅲa， 3 as Ⅲa→Ⅲb， 1 as Ⅲb→Ⅳ. Conclusion Detection of D2-40 and CK in diagnosis of LVI and LN micrometastasis is better than HE staining. The combined detection of CK20 and CKpan may be much easier to find out the LN with micrometastasis. Later stage of TNM the tumor is, more frequently the LN micrometastasis happens. The relationships of LVI-IM, LVD and LN micrometastasis with LN metastasis in gastric cancer has been demonstrated. Patients with higher LVD share a lower survival rate in early period of follow-up.