Expression levels of HMGA2 and CD9 and its clinicopathological significances in the benign and malignant lesions of the gallbladder

Decoding high mobility group A2 protein expression regulation and implications in human cancers

High Mobility Group A2 (HMGA2) oncofetal proteins are a distinct category of Transcription Factors (TFs) known as "architectural factors" due to their lack of direct transcriptional activity. Instead, they modulate the three-dimensional structure of chromatin by binding to AT-rich regions in the minor grooves of DNA through their AT-hooks. This binding allows HMGA2 to interact with other proteins and different regions of DNA, thereby regulating the expression of numerous genes involved in carcinogenesis. Consequently, multiple mechanisms exist to finely control HMGA2 protein expression at various transcriptional levels, ensuring precise concentration adjustments to maintain cellular homeostasis. During embryonic development, HMGA2 protein is highly expressed but becomes absent in adult tissues. However, recent studies have revealed its re-elevation in various cancer types. Extensive research has demonstrated the involvement of HMGA2 protein in carcinogenesis at multiple levels. It intervenes in crucial processes such as cell cycle regulation, apoptosis, angiogenesis, epithelial-to-mesenchymal transition, cancer cell stemness, and DNA damage repair mechanisms, ultimately promoting cancer cell survival. This comprehensive review provides insights into the HMGA2 protein, spanning from the genetic regulation to functional protein behavior. It highlights the significant mechanisms governing HMGA2 gene expression and elucidates the molecular roles of HMGA2 in the carcinogenesis process.

Effects of HMGA2 on the biological characteristics and stemness acquisition of gastric cancer cells

BACKGROUND AND STUDY AIMS

The high mobility group A2 (HMGA2), a nonhistone nuclear binding protein, modulates transcription by altering the chromatin architecture of the target gene DNA in its specific AT-hooks region. HMGA2 overexpression has been observed in embryonic tissue and many malignant neoplasms. This study sought to verify whether HMGA2 plays a role in the biological functions of gastric cancer cells, such as cell proliferation, invasiveness, migration, and stem cell acquisition, and to provide some ideas for further research on the metastatic mechanism of gastric cancer.

PATIENTS AND METHODS

HMGA2's effects on the proliferation, invasiveness, and migration capabilities of gastric cancer cells were individually detected by BrdU, Transwell, and wound healing assays. Western blotting and immunofluorescence were used to evaluate whether HMGA2 could promote the acquisition of gastric cancer cells. Biostatistical analyses were performed using SPSS 17.0 for Windows.

RESULTS

HMGA2 expression levels in gastric cancer cell lines were significantly higher than those in human immortalized gastric epithelial cell lines (p < 0.01). Gastric cancer cell proliferation was inhibited when HMGA2 was overexpressed (p < 0.05). The invasiveness and migration capabilities of gastric cancer cells with HMGA2 overexpression were enhanced more than those of the corresponding control groups (p < 0.05). HMGA2 overexpression promotes the stemness acquisition of stem cells from gastric cancer cells.

CONCLUSIONS

This study verified that the HMGA2 structural transcription factor promotes invasiveness, migration, and acquisition of gastric cancer cells. Furthermore, our findings provide significant insight for further research on the metastatic mechanism of gastric cancer.

Prognostic value and multifaceted roles of tetraspanin CD9 in cancer

CD9 is a crucial regulator of cell adhesion in the immune system and plays important physiological roles in hematopoiesis, blood coagulation or viral and bacterial infections. It is involved in the transendothelial migration of leukocytes which might also be hijacked by cancer cells during their invasion and metastasis. CD9 is found at the cell surface and the membrane of exosomes affecting cancer progression and therapy resistance. High expression of CD9 is mostly associated with good patients outcome, with a few exceptions. Discordant findings have been reported for breast, ovarian, melanoma, pancreatic and esophageal cancer, which might be related to using different antibodies or inherent cancer heterogeneity. According to in vitro and in vivo studies, tetraspanin CD9 is not clearly associated with either tumor suppression or promotion. Further mechanistic experiments will elucidate the role of CD9 in particular cancer types and specific conditions.

HMGA2 promotes the migration and invasion of gallbladder cancer cells and HMGA2 knockdown inhibits angiogenesis via targeting VEGFA

The high mobility group AT-hook 2 (HMGA2) protein has been found to be upregulated in the majority of tumor types and is associated with a poor prognosis. Previous studies have suggested the oncogenic role of HMGA2 in gallbladder cancer (GBC). The present study aimed to investigate the effects of HMGA2 on the invasion, migration and angiogenesis of GBC cells. To achieve this aim, HMGA2 was overexpressed or silenced in the GBC cell line, EH-GB1, and then the proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) abilities of EH-GB1 cells were investigated using Cell Counting Kit-8, wound healing, Transwell and western blotting assays. In addition, the expression levels of VEGFA were determined in EH-GB1 cells using western blotting and reverse transcription-quantitative PCR following HMGA2 overexpression or silencing. Furthermore, HMGA2-silenced EH-GB1 cells were transfected with VEGFA overexpression plasmids to evaluate the tube formation ability of HUVECs using tube formation assay. The results demonstrated that HMGA2 silencing inhibited GBC cell proliferation, migration, invasion and EMT, as evidenced by the downregulated expression of Ki67, proliferating cell nuclear antigen, MMP2, MMP9, N-cadherin, snail family transcriptional repressor 2 and zinc finger E-box-binding homeobox 1, and attenuated cell migration and invasion. However, the opposite results were obtained following HMGA2 overexpression. Moreover, HMGA2 knockdown and overexpression downregulated and upregulated VEGFA expression, respectively. In addition, the tube formation ability of HUVECs and the expression levels of CD31, VEGFR1 and VEGFR2 were downregulated following HMGA2 silencing. However, these effects were partially rescued by simultaneous VEGFA overexpression. In conclusion, the findings of the present study revealed that HMGA2 may promote GBC cell migration, invasion, EMT and angiogenesis. Therefore, inhibiting HMGA2 expression could be considered as a possible therapeutic approach for GBC.

Prognostic Value of CD9 in Solid Tumor: A Systematic Review and Meta-Analysis

Numerous clinical studies investigated how low expression of CD9 predicts poor prognosis of solid tumor. However, the results were inconclusive. This present meta-analysis was therefore performed to determine the prognostic value of CD9 expression in solid tumors. In this meta-analysis, 25 studies involving 5,555 participants were included; the result showed strong significant associations between declined expression of CD9 and all endpoints: overall survival (OS) (hazard ratio (HR) = 1.88, 95% CI = 1.45-2.43, p < 0.000) and time to progression (TTP) (HR = 2.0, 95% CI = 1.38-2.88, p < 0.000). The subgroup analysis was also performed, which revealed that the associations between CD9 downregulated expression related to poor OS in lung cancer and head and neck cancer. Also, low expression of CD9 was significantly connected with poor TTP in patients with head and neck cancer. The adverse prognostic impact of decreased expression of CD9 was observed in patients of different ethnicities. In conclusion, these results showed that declined expression of CD9 was associated with poor survival in human solid tumors. CD9 may be a valuable prognostic predictive biomarker and a potential therapeutic target in human solid tumors.

Increased CD9 expression predicts favorable prognosis in human cancers: a systematic review and meta-analysis

Background

CD9 is implicated in cancer progression and metastasis by its role in suppressing cancer cell proliferation and survival. However, the prognostic and clinicopathological significance of CD9 expression is controversial. Therefore, the current meta-analysis was conducted to determine the prognostic and clinicopathological significance of CD9 expression in cancer patients.

Methods

Eligible studies were selected through database search of PubMed, Embase and Cochrane library up to April 5 2020. The necessary data were extracted from the included studies. Pooled hazard ratio (HR) and odds ratio (OR) with 95% confidence interval (CI) were calculated to evaluate the prognostic and clinicopathological significance of CD9 expression in cancer patients.

Results

A total of 17 studies consisting of 3456 cancer patients were included in this meta-analysis. An increased CD9 expression was significantly associated with a more favorable overall survival (OS) (HR 0.47, 95% CI 0.31–0.73, p = 0.001) and disease-free survival (DFS) (HR 0.48, 95% CI 0.30–0.79, p = 0.003). In subgroup analysis of cancer type, an increased CD9 expression was associated with increased OS in breast cancer and digestive system cancer, and with increased DFS in head and neck cancer and leukemia/lymphoma. Additionally, an increased CD9 expression significantly correlated with lower overall stage (OR 0.45, 95% CI 0.29–0.72, p = 0.001).

Conclusion

An increased CD9 expression was associated with favorable survival in cancer patients suggesting that CD9 expression could be a valuable survival factor in cancer patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02152-y.

High mobility group A protein-2 as a tumor cancer diagnostic and prognostic marker: a systematic review and meta-analysis

High mobility group A protein-2 (HMGA2) is an architectural transcription factor that binds to the A/T-rich DNA minor groove and is responsible for regulating transcriptional activity of multiple genes indirectly through chromatin change and assembling enhanceosome. HMGA2 is overexpressed in multiple tumor types, suggesting its involvement in cancer initiation and progression, thus, making it an ideal candidate for cancer diagnostic and prognostic. We performed a systematic review to examine the role of HMGA2 as a universal tumor cancer diagnostic and prognostic marker. We used Reporting Recommendations for Tumor Marker Prognostic Studies to systematically search OvidMedline, PubMed, and the Cochrane Library for English language studies, published between 1995 and June 2019. Meta-analysis provided pooled risk estimates and their 95% confidence intervals (CIs) for an association between overall survival and recurrence of cancers for studies with available estimates. We identified 42 eligible studies with a total of 5123 tumor samples in 15 types of cancer. The pooled percentage of HMGA2 gene expression in tumor samples was 65.14%. Meta-analysis showed that cancer patients with HMGA2 positive have significantly reduced survival, compared to patients without HMGA2 gene [pooled-hazard ratio (HR) = 1.85, 95% CI 1.48-2.22]. There was a positive association between cancer patients with HMGA2 overexpression and cancer recurrence though this association did not reach significance (pooled-HR = 1.44, 95% CI 0.80-2.07). Overexpression of HMGA2 was found in 15 types of cancer. There was an association between HMGA2 overexpression with reduced survival of cancer patients. HMGA2 is thus considered a promising universal tumor marker for prognostics.

TSPAN8 as a Novel Emerging Therapeutic Target in Cancer for Monoclonal Antibody Therapy

Tetraspanin 8 (TSPAN8) is a member of the tetraspanin superfamily that forms TSPAN8-mediated protein complexes by interacting with themselves and other various cellular signaling molecules. These protein complexes help build tetraspanin-enriched microdomains (TEMs) that efficiently mediate intracellular signal transduction. In physiological conditions, TSPAN8 plays a vital role in the regulation of biological functions, including leukocyte trafficking, angiogenesis and wound repair. Recently, reports have increasingly shown the functional role and clinical relevance of TSPAN8 overexpression in the progression and metastasis of several cancers. In this review, we will highlight the physiological and pathophysiological roles of TSPAN8 in normal and cancer cells. Additionally, we will cover the current status of monoclonal antibodies specifically targeting TSPAN8 and the importance of TSPAN8 as an emerging therapeutic target in cancers for monoclonal antibody therapy.

Oncological role of HMGA2 (Review)

The high mobility group A2 (HMGA2) protein is a non‑histone architectural transcription factor that modulates the transcription of several genes by binding to AT‑rich sequences in the minor groove of B‑form DNA and alters the chromatin structure. As a result, HMGA2 influences a variety of biological processes, including the cell cycle process, DNA damage repair process, apoptosis, senescence, epithelial‑mesenchymal transition and telomere restoration. In addition, the overexpression of HMGA2 is a feature of malignancy, and its elevated expression in human cancer predicts the efficacy of certain chemotherapeutic agents. Accumulating evidence has suggested that the detection of HMGA2 can be used as a routine procedure in clinical tumour analysis.

Medicinal plants in traumatic brain injury: Neuroprotective mechanisms revisited

Traumatic brain injury (TBI) is the most prevalent health problem affecting all age groups, and leads to many secondary problems in other organs especially kidneys, gastrointestinal tract, and heart function. In this review, the search terms were TBI, fluid percussion injury, cold injury, weight drop impact acceleration injury, lateral fluid percussion, cortical impact injury, and blast injury. Studies with Actaea racemosa, Artemisia annua, Aframomum melegueta, Carthamus tinctorius, Cinnamomum zeylanicum, Crocus sativus, Cnidium monnieri, Curcuma longa, Gastrodia elata, Malva sylvestris, Da Chuanxiong Formula, Erigeron breviscapus, Panax ginseng, Salvia tomentosa, Satureja khuzistanica, Nigella sativa, Drynaria fortune, Dracaena cochinchinensis, Polygonum cuspidatum, Rosmarinus officinalis, Rheum tanguticum, Centella asiatica, and Curcuma zedoaria show a significant decrease in neuronal injury by different mechanisms such as increasing superoxide dismutase and catalase activities, suppressing nuclear factor kappa B (NF-κB), interleukin 1 (IL-1), glial fibrillary acidic protein, and IL-6 expression. The aim of this study was to evaluate the neuroprotective effects of medicinal plants in central nervous system pathologies by reviewing the available literature.

Prognostic value of high mobility group protein A2 (HMGA2) over-expression in cancer progression

The high mobility group A2 (HMGA2; also called HMGI-C) gene is an architectural transcription factor that belonging to the high mobility group AT-hook (HMGA) gene family. HMGA2 is aberrantly regulated in several human tumors. Over-expression of HMGA2 is correlated with a higher risk of metastasis and an unfavorable prognosis in patients with cancer. We performed a meta-analysis to determine the clinic-pathological and prognostic value of HMGA2 overexpression in different human tumors. A comprehensive literature search was performed using PubMed, Embase, Cochrane Library, Scopus, MEDLINE, Google Scholar and ISI Web of Science. Hazard ratios (HRs)/odds ratios (ORs) and their 95% confidence intervals (CIs) were used to assess the strength of the association between HMGA2 expression and overall survival (OS)/progression free survival (PFS)/disease free survival (DFS). A total of 5319 patients with 19 different types of cancer from 35 articles were evaluated. Pooled data analysis indicated that increased HMGA2 expression in cancer patients predicted a poor OS (HR = 1.70; 95% CI = 1.6-1.81; P < 0.001; fixed-effect model). In subgroup analyses, high HMGA2 expression was particularly associated with poor OS in individuals with gastrointestinal (GI) cancer (HR = 1.89, 95% CI: 1.83-1.96; fixed-effect model) and HNSCC cancer (HR-1.78, 95%CI: 1.44-2.21; fixed-effect model). Over-expression of HMGA2 was associated with vascular invasion (OR = 0.16, 95% CI = 0.05-0.49; P = 0.001) and lymphatic invasion (OR = 1.89, 95% CI = 1.06-3.38; P = 0.032). Further studies should be conducted to validate the prognostic value of HMGA2 for patients with GI cancers.

Curcumin: a potent agent to reverse epithelial-to-mesenchymal transition

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is involved in tumor progression, invasion, migration and metastasis. EMT is a process by which polarized epithelial cells acquire motile mesothelial phenotypic features. This process is initiated by disassembly of cell-cell contacts through the loss of epithelial markers and replacement of these markers by mesenchymal markers. Reconstruction of the cytoskeleton and degradation of the tumor basement membrane ensures the spread of invasive malignant tumor cells to distant locations. Accumulating evidence indicates that curcumin, as a well-known phytochemical, can inhibit EMT/metastasis through various mechanisms and pathways in human tumors.

CONCLUSIONS

In this review, we summarize the mechanisms by which curcumin may affect EMT in cells under pathological conditions to understand its potential as a novel anti-tumor agent. Curcumin can exert chemo-preventive effects by inhibition and reversal of the EMT process through both TGF-β-dependent (e.g. in hepatoma and retinal pigment epithelial cancer) and -independent (e.g. in oral cancer, colorectal cancer, pancreatic cancer, hepatocellular carcinoma, breast cancer, melanoma, prostate cancer, bladder cancer, thyroid cancer and lung cancer) pathways. Curcumin can also mitigate chemoresistance through EMT suppression and promotion of the antiproliferative effects of conventional chemotherapeutics. Therefore, curcumin has the potential to be used as a novel adjunctive agent to prevent tumor metastasis, which may at least partly be attributed to its hampering of the EMT process.

Weighted gene co-expression network analysis and prognostic analysis identifies hub genes and the molecular mechanism related to head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a lethal disease with suboptimal survival outcomes. In this study, we aimed to find an independent prognostic factor of head and neck squamous cell carcinoma and investigate its effect on tumor cell proliferation, apoptosis, migration progress and cell cycle phase. Weighted gene co-expression network analysis (WGCNA) is an analysis method for mining module information in chip data through soft threshold. In this article, it was used to divide differential genes into different modules and determined the ten hub genes. Overall survival (OS) and disease-free survival (DFS) analyses as well as univariate and multivariate regression analyses were used to figure out HMGA2 as the independent prognostic factor. RT-qPCR and western blot results revealed the HMGA2 expression levels. Via colony formation, flow cytometry and wound healing assays, we tested the involvement of HMGA2 knockdown in corresponding cancer cell biological behaviors. HMGA2 level was up-regulated in HNSCC tissues and cell lines (SCC-25 and FaDu) in comparison with their normal counterparts. HMGA2 knockdown decreased cancer cell proliferation, promoted cell apoptosis, blocked cell cycle at G0/G1 phase, and inhibited cell migration. We regarded HMGA2 as a potential diagnostic and therapeutic target of HNSCC.

The expressions of HMGA2 and Thy1 in extrahepatic cholangiocarcinoma and their clinicopathological significances

AIMS

Extrahepatic cholangiocarcinoma is a malignant tumor and poor prognosis with intrinsic resistance to cytotoxic agents. The molecular mechanism associated with high malignancy and resistance to chemotherapy and radiotherapy has not been fully elucidated. This study aims to investigate the clinicopathological significances of HMGA2 and Thy1 expression in extrahepatic cholangiocarcinoma.

METHODS

The expressions of HMGA2 and Thy1 in 100 extrahepatic cholangiocarcinoma, 30 peritumoral tissues, 10 adenoma and 15 normal biliary tract tissues were assayed using EnVision immunohistochemistry.

RESULTS

The HMGA2 and Thy1 proteins were overexpression in extrahepatic cholangiocarcinoma compared to peritumoral tissues, adenoma, and normal biliary tract tissues (P < 0.05 or P < 0.01). Adenoma and pericancerous tissues with positive HMGA2 or/and Thy1 protein expression exhibited atypical hyperplasia. The positive correlation was found between the expression of HMGA2 and Thy1 in extrahepatic cholangiocarcinoma (P < 0.01). The positive rates of HMGA2 and Thy1 expression were significantly higher in cases with poor differentiation, lymph node metastasis, invasion, and TNM stage III or IV and no resection (biopsy only) (P < 0.05 or P < 0.01). Kaplan-Meier survival analysis showed that the survival of extrahepatic cholangiocarcinoma patients with positive HMGA2 and/or Thy1 expression is significantly shorter than patients with negative HMGA2 and/or Thy1 expression (P = 0.000). Cox multivariate analysis revealed that positive HMGA2 and/or Thy1 expressions were independently poor prognosis factors in extrahepatic cholangiocarcinoma patients. We calculated the AUC for HMGA2 (AUC = 0.610, 95%CI: 0.519-0.702), or Thy1 (AUC = 0.675, 95%CI: 0.588-0.762), respectively.

CONCLUSIONS

The present study indicated that positive HMGA2 and Thy1 expression are closely associated with the pathogenesis, clinical, pathological and biological behaviors, and poor prognosis in patients with extrahepatic cholangiocarcinoma.

MiR‑495 suppresses cell proliferation by directly targeting HMGA2 in lung cancer

The present study aimed to investigate the expression of microRNA-495 (miR-495) in non-small cell lung cancer (NSCLC) tissues and cells, as well as its function on the proliferation of lung cancer cells. The expression of miR-495 in 122 pairs of NSCLC tissues and matched paracarcinoma tissues, as well as in human lung cancer cell lines (A549, H460, H1650, H520 and SK-MES-1) and the normal human pulmonary bronchial epithelial cell line 16HBE was determined using reverse transcription quantitative polymerase chain reaction (RT-qPCR). As predicted by bioinformatics analysis, high mobility group A2 (HMGA2) may be a potential target gene of miR-495. In addition, the regulatory function of miR-495 on its target gene HMGA2 was evaluated using a dual-luciferase reporter assay, RT-qPCR and western blotting. Furthermore, the effect of miR-495 on the proliferation of A549 lung cancer cells was investigated using a Cell Counting Kit-8 (CCK-8) assay. The results demonstrated that the expression of miR-495 in NSCLC tissues and cells was significantly downregulated compared with the control. In addition, downregulated expression of miR-495 was associated with tumor differentiation, lymph node metastasis and tumor, node and metastasis staging. Additionally, a dual-luciferase reporter assay revealed that miR-495 could directly associated with the 3′-untranslated region of HMGA2. Upregulated expression of miR-495 significantly downregulated the mRNA and protein expression levels of HMGA2 in A549 cells. Furthermore, the results of CCK-8 assay revealed that upregulated expression of miR-495 significantly suppressed the proliferation of A549 cells; HMGA2 overexpression reversed this inhibition. In summary, the findings of the present study demonstrated that miR-495 was downregulated in NSCLC tissues and cells. In addition, miR-495 suppressed the proliferation of lung cancer cells by directly targeting HMGA2.

miR‑539 suppresses proliferation and induces apoptosis in renal cell carcinoma by targeting high mobility group A2

Renal cell carcinoma (RCC) is one of the most common urinary malignancies with a high rate of morbidity. MicroRNAs (miRNAs) have been shown to be critical post-transcriptional regulators in tumorigenesis. The present study aimed to investigate the effect of miRNA (miR)-539 on the proliferation and apoptosis of RCC. The expression of miR-539 and high mobility group AT-hook 2(HMGA2) were examined in clinical RCC specimens. The 786-O RCC cell line was also used and was transfected with miR-539 mimics or inhibitors. The correlation between miR-539 and HMGA2 was confirmed using a luciferase reporter assay. Cell viability and apoptosis were detected using MTT and flow cytometry assays. The protein levels of HMGA2, AKT, phosphorylated (p)-AKT, mammalian target of rapamycin (mTOR) and p-mTOR were analyzed using western blot analysis. The results revealed that miR-539 was negatively correlated with the expression of HMGA2 in clinical RCC specimens. Further experiments identified HMGA2 as a direct target of miR-539. The overexpression of miR-539 downregulated the expression of HMGA2, reduced cell proliferation and promoted cell apoptosis, whereas the knockdown of miR-539 led to the opposite results. miR-539 also suppressed the phosphorylation of AKT and mTOR, without altering the levels of total AKT and mTOR. Taken together, the results of the present study indicated that miR-539 negatively regulated the expression of HMGA2 in clinical specimens and in vitro. miR539 inhibited cell proliferation and induced apoptosis in RCC cells. This regulatory effect of miR-539 may be associated with the AKT signaling pathway. Therefore, miR-539 may be used as a biomarker for predicting the progression of RCC.

High mobility group protein A2 overexpression indicates poor prognosis for cancer patients: a meta-analysis

Overexpression of the high mobility group protein A2 (HMGA2), an architectural transcription factor, has been linked to poor prognosis in many malignancies, although this remains controversial. Herein, we conducted a meta-analysis to investigate whether HMGA2 has prognostic value, and evaluated the association between HMGA2 and clinicopathologic factors in malignancies. A total of 29 studies involving 4114 patients were included in this meta-analysis. The pooled results demonstrated that elevated HMGA2 predicted a poor overall survival (OS) (hazard ratio [HR] = 1.82; 95% confidence interval [CI] = 1.62-2.05; P < 0.001) and disease-free survival/progression-free survival/recurrence-free survival (HR = 1.94; 95% CI = 1.27-2.98; P = 0.002). Subgroup analysis conducted by study region, sample size, detection method, and analysis method indicated that HMGA2 overexpression correlated with poor OS. Furthermore, HMGA2 overexpression was found to be linked to poor OS in various cancers except ovarian cancer (pooled HR = 1.14; 95% CI = 0.62-2.09; P = 0.673). High HMGA2 expression level also correlated with advanced TNM stage (OR = 2.44; 95% CI =1.87-3.2; P < 0.001), lymphovascular invasion (OR = 2.46, 95% CI = 1.67-3.64; P < 0.001), distant metastasis (OR = 2.66; 95% CI =1.51-4.69; P < 0.001), and lymph node metastasis (OR = 1.83; 95% CI =1.27-2.64; P = 0.001). In conclusion, HMGA2 overexpression indicates a worse prognosis and may serve as a prognostic predictor in cancer patients.

Gallbladder cancer epidemiology, pathogenesis and molecular genetics: Recent update

Gallbladder cancer is a malignancy of biliary tract which is infrequent in developed countries but common in some specific geographical regions of developing countries. Late diagnosis and deprived prognosis are major problems for treatment of gallbladder carcinoma. The dramatic associations of this orphan cancer with various genetic and environmental factors are responsible for its poorly defined pathogenesis. An understanding to the relationship between epidemiology, molecular genetics and pathogenesis of gallbladder cancer can add new insights to its undetermined pathophysiology. Present review article provides a recent update regarding epidemiology, pathogenesis, and molecular genetics of gallbladder cancer. We systematically reviewed published literature on gallbladder cancer from online search engine PubMed (http://www.ncbi.nlm.nih.gov/pubmed). Various keywords used for retrieval of articles were Gallbladder, cancer Epidemiology, molecular genetics and bullion operators like AND, OR, NOT. Cross references were manually searched from various online search engines (http://www.ncbi.nlm.nih.gov/pubmed,https://scholar.google.co.in/, http://www.medline.com/home.jsp). Most of the articles published from 1982 to 2015 in peer reviewed journals have been included in this review.

Gallbladder Cancer in the 21st Century

Gallbladder cancer (GBC) is an uncommon disease in the majority of the world despite being the most common and aggressive malignancy of the biliary tree. Early diagnosis is essential for improved prognosis; however, indolent and nonspecific clinical presentations with a paucity of pathognomonic/predictive radiological features often preclude accurate identification of GBC at an early stage. As such, GBC remains a highly lethal disease, with only 10% of all patients presenting at a stage amenable to surgical resection. Among this select population, continued improvements in survival during the 21st century are attributable to aggressive radical surgery with improved surgical techniques. This paper reviews the current available literature of the 21st century on PubMed and Medline to provide a detailed summary of the epidemiology and risk factors, pathogenesis, clinical presentation, radiology, pathology, management, and prognosis of GBC.

Tetraspanins as regulators of the tumour microenvironment: implications for metastasis and therapeutic strategies

One of the hallmarks of cancer is the ability to activate invasion and metastasis. Cancer morbidity and mortality are largely related to the spread of the primary, localized tumour to adjacent and distant sites. Appropriate management and treatment decisions based on predicting metastatic disease at the time of diagnosis is thus crucial, which supports better understanding of the metastatic process. There are components of metastasis that are common to all primary tumours: dissociation from the primary tumour mass, reorganization/remodelling of extracellular matrix, cell migration, recognition and movement through endothelial cells and the vascular circulation and lodgement and proliferation within ectopic stroma. One of the key and initial events is the increased ability of cancer cells to move, escaping the regulation of normal physiological control. The cellular cytoskeleton plays an important role in cancer cell motility and active cytoskeletal rearrangement can result in metastatic disease. This active change in cytoskeletal dynamics results in manipulation of plasma membrane and cellular balance between cellular adhesion and motility which in turn determines cancer cell movement. Members of the tetraspanin family of proteins play important roles in regulation of cancer cell migration and cancer-endothelial cell interactions, which are critical for cancer invasion and metastasis. Their involvements in active cytoskeletal dynamics, cancer metastasis and potential clinical application will be discussed in this review. In particular, the tetraspanin member, CD151, is highlighted for its major role in cancer invasion and metastasis.

LINKED ARTICLES

This article is part of a themed section on Cytoskeleton, Extracellular Matrix, Cell Migration, Wound Healing and Related Topics. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-24.

High-mobility group AT-hook 2: an independent marker of poor prognosis in intrahepatic cholangiocarcinoma

High-mobility group AT-hook 2 (HMGA2) regulates cell growth, differentiation, apoptosis, and neoplastic transformation. Previous studies have shown that malignant tumors expressing HMGA2, such as gastric, lung, and colorectal carcinomas, usually have a poor prognosis. HMGA2 expression and its clinical significance in intrahepatic cholangiocarcinomas have not been studied. We identified 55 intrahepatic cholangiocarcinomas resected at our institution from 1994 to 2003. Hematoxylin-eosin-stained slides were reviewed, and histopathologic characteristics were recorded, including mitotic count, tumor grade, vascular and perineural invasion, lymph node metastasis, and margin status. Using immunohistochemical stains, we examined expression of HMGA2, p53, p16, Kit, α-fetoprotein, and Ki-67, and we analyzed the correlation of survival with clinicopathological characteristics and immunohistochemical findings. Positive staining for HMGA2, p53, p16, Kit, α-fetoprotein, and Ki-67 was seen in 18 (33%), 37 (69%), 26 (47%), 21 (38%), 2 (4%), and 34 (63%) tumors, respectively. HMGA2 expression correlated positively with p53 expression (P = .02; ρ = 0.32) and negatively with p16 expression (P = .04; ρ = -0.28). Univariate analysis showed that HMGA2 expression and lymph node metastasis were associated with shorter patient survival and were independent indicators of poor survival (P = .02 and P = .03, respectively). Tumorigenic effects of HMGA2 in intrahepatic cholangiocarcinoma may partly reflect its ability to negatively regulate expression of p16 tumor suppressors and to be associated with p53 abnormalities.

Coexpression of HMGA2 and Oct4 predicts an unfavorable prognosis in human gastric cancer

High mobility group protein A2 (HMGA2) and octamer-binding transcription factor 4 (Oct4) are transcription factors that play major roles in the acquisition of cancer stemness phenotypes and tumorigenicity of malignant neoplasms. The aim of this study was to analyze the association between HMGA2 and Oct4 expression and various clinicopathologic features in gastric cancer patients including invasion, metastasis, and clinical prognosis, in addition to overall survival. Immunohistochemistry was performed to explore the expression of HMGA2 and Oct4 in 158 gastric cancer and surrounding non-tumor tissues. Moreover, HMGA2 and Oct4 mRNA and protein levels were also detected by qRT-PCR and Western blotting, respectively, in 86 clinical tissue specimens and various gastric epithelial cell lines (GES-1, SGC7901, MKN45, and MKN27). Finally, associations between HMGA2 and Oct4 expression and clinicopathological features were analyzed by Pearson correlation coefficient. Survival analysis was performed by univariate and multivariate analyses. Taken together, we found that HMGA2 and Oct4 expression was significantly higher in gastric cancer tissues compared with non-cancerous tissues (P < 0.01), and HMGA2 and Oct4 protein levels were significantly higher in poorly differentiated gastric cancer cell lines (MKN45), moderately differentiated cell lines (SGC7901), and well-differentiated cell lines (MKN28) compared with human immortalized gastric epithelial cell lines (GES-1) (P < 0.01). Elevated HMGA2 and Oct4 levels were significantly associated with poor clinical prognosis (P < 0.05). Further conclusion showed that coexpression of HMGA2 and Oct4 in gastric cancer correlated with tumor invasion, metastasis, and clinical prognosis and predicted an unfavorable clinical outcome. These transcription factors may represent useful biomarkers to identify patients at high risk of postoperative recurrence.

A genetic model for gallbladder carcinogenesis and its dissemination

Gallbladder cancer, although regarded as the most common malignancy of the biliary tract, continues to be associated with a dismal overall survival even in the present day. While complete surgical removal of the tumour offers a good chance of cure, only a fraction of the patients are amenable to curative surgery owing to their delayed presentation. Moreover, the current contribution of adjuvant therapies towards prolonging survival is marginal, at best. Thus, understanding the biology of the disease will not only enable a better appreciation of the pathways of progression but also facilitate the development of an accurate genetic model for gallbladder carcinogenesis and dissemination. This review provides an updated, evidence-based model of the pathways of carcinogenesis in gallbladder cancer and its dissemination. The model proposed could serve as the scaffolding for elucidation of the molecular mechanisms involved in gallbladder carcinogenesis. A better understanding of the pathways involved in gallbladder tumorigenesis will serve to identify patients at risk for the cancer (and who thus could be offered prophylactic cholecystectomy) as well as aid oncologists in planning the most suitable treatment for a particular patient, thereby setting us on the vanguard of transforming the current treatment paradigm for gallbladder cancer.

Expression and clinicopathological significance of CD9 in gastrointestinal stromal tumor

This study investigated the expression and clinicopathological significance of CD9 in gastrointestinal stromal tumor (GIST). Immunohistochemistry staining for CD9 was performed on tumor tissues from 74 GIST patients. The correlation with clinicopathological features, risk classification and prognosis was analyzed. CD9-positive staining comprised 59.5% (44/74) of the GIST patients. The CD9-positive expression rate of the sample was significantly associated with diameter (P = 0.028), mitotic counts (P = 0.035), risk classification (P = 0.018) and three-year recurrence-free survival (RFS) (P < 0.001). Cox proportional hazards regression (HR = 0.352; P = 0.015) showed that CD9 is an independent factor for post-operative RFS. The subgroup analysis showed that CD9 expression in gastric stromal tumor (GST) is significantly associated with diameter (P = 0.031), risk classification (P = 0.023) and three-year RFS (P = 0.001). The Cox proportional hazards regression (HR = 0.104; P = 0.006) also showed that CD9 is an independent factor for RFS of GST. However, CD9 expression does not have a statistically significant correlation with clinicopathological features, risk classification, and prognosis in non-GST. In conclusion, CD9 expression in GIST appears to be associated with the recurrence and/or metastasis of GIST patients, especially in GST, which may indicate the important role of CD9 in the malignant biological behavior and prognosis of GST.

Knockout of the tetraspanin Cd9 in the TRAMP model of de novo prostate cancer increases spontaneous metastases in an organ-specific manner

Prostate cancer is an extremely heterogeneous disease; patients that do progress to late-stage metastatic prostate cancer have limited treatment options, mostly palliative. Molecules involved in the metastatic cascade may prove beneficial in stratifying patients to assign appropriate treatment modalities and may also prove to be therapeutic antimetastatic targets. The tetraspanin group of molecules are integral membrane proteins that associate with motility-related proteins such as integrins. Clinical studies have mostly shown that reduced expression levels of the tetraspanin CD9 are correlated with tumour progression in a range of cancers. Furthermore, functional studies have shown CD9 to be involved in cell motility and adhesion and that it may influence metastasis. The effects of endogenous CD9 on prostate cancer initiation and progression were analysed by crossing a Cd9-/- (KO) murine model with a model of de novo developing and spontaneously metastasising prostate cancer, namely the transgenic adenocarcinoma of mouse prostate model. Our study demonstrates for the first time that ablation of Cd9 had no detectable effect on de novo primary tumour onset, but did significantly increase metastasis to the liver but not the lungs.