Targeting HOX/PBX dimer formation as a potential therapeutic option in esophageal squamous cell carcinoma.

Homeobox genes are known to be classic examples of the intimate relationship between embryogenesis and tumorigenesis, which are a family of transcriptional factors involved in determining cell identity during early development, and also dysregulated in many malignancies. Previously, HOXB7, HOXC6 and HOXC8 were found abnormally upregulated in esophageal squamous cell carcinoma (ESCC) tissues compared with normal mucosa and seen as poor prognostic predictors for ESCC patients, and were shown to promote cell proliferation and anti-apoptosis in ESCC cells. These three HOX members have a high level of functional redundancy, making it difficult to target a single HOX gene. The aim of the present study was to explore whether ESCC cells are sensitive to HXR9 disrupting the interaction between multiple HOX proteins and their cofactor PBX, which is required for HOX functions. ESCC cell lines (KYSE70, KYSE150, KYSE450) were treated with HXR9 or CXR9, and coimmunoprecipitation and immunofluorescent colocalization were carried out to observe HOX/PBX dimer formation. To further investigate whether HXR9 disrupts the HOX pro-oncogenic function, CCK-8 assay and colony formation assay were carried out. Apoptosis was assessed by flow cytometry, and tumor growth in vivo was investigated in a xenograft model. RNA-seq was used to study the transcriptome of HXR9-treated cells. Results showed that HXR9 blocked HOX/PBX interaction, leading to subsequent transcription alteration of their potential target genes, which are involved in JAK-signal transducer and activator of transcription (STAT) activation and apoptosis inducement. Meanwhile, HXR9 showed an antitumor phenotype, such as inhibiting cell proliferation, inducing cell apoptosis and significantly retarding tumor growth. Therefore, it is suggested that targeting HOX/PBX may be a novel effective treatment for ESCC.

P21, COX-2, and E-cadherin are potential prognostic factors for esophageal squamous cell carcinoma.

Much research effort has been devoted to identifying prognostic factors for esophageal squamous cell carcinoma (ESCC) by immunohistochemistry; however, no conclusive findings have been reached thus far. We hypothesized that certain molecules identified in previous studies might serve as useful prognostic markers for ESCC. Therefore, the aim of the current study was to validate the most relevant markers showing potential for ESCC prognosis in our prospective esophageal cancer database. A literature search was performed using the PubMed database for papers published between 1980 and 2015 using the following key words: 'esophageal cancer,' 'prognosis,' and 'immunohistochemistry.' Literature selection criteria were established to identify the most widely studied markers, and we further validated the selected markers in a cohort from our single-surgeon team, including 153 esophageal cancer patients treated from 2000 to 2010. A total of 1799 articles were identified, 82 of which met the selection criteria. Twelve markers were found to be the most widely studied, and the validation results indicated that only P21, COX-2, and E-cadherin were independent prognostic factors for ESCC patients in this series. The systemic review and cohort validation suggest that P21, COX-2, and E-cadherin are potential prognostic factors for ESCC, paving the way for more targeted prospective validation in the future.

The survival predictive significance of HOXC6 and HOXC8 in esophageal squamous cell carcinoma.

BACKGROUND & AIM: Esophageal squamous cell carcinoma (ESCC), a common disease in China, is mainly treated surgically. We established a prospective database of patients with esophageal cancer between January 2000 and December 2010, including 486 subjects with ESCC who underwent surgical treatment. In this study, we explored the prognostic significance of the expressions of HOXC6 and HOXC8, responsible for embryonic development, by studying the specimens collected from clinical subjects during strict follow-up periods. MATERIALS & METHODS: Immunohistochemistry was used to detect the expressions of HOXC6 and HOXC8 in 274 ESCC subjects including 138 ESCC subjects treated with surgery alone and 136 ESCC subjects treated with neoadjuvant chemotherapy. Survival analysis was performed from the day of surgery to August 2013. RESULTS: The 5-y survival rate of the 274 ESCC subjects was 44.2%, with a median survival time of 44.12 mo. For the 274 ESCC subjects involved in the investigation of HOXC6 and HOXC8 expressions, the median survival time of subjects with high-level expressions of HOXC6 and HOXC8 was shorter than that for subjects with low-level expressions (P = 0.001, P < 0.001, respectively). Similar results were obtained from the analysis of the prognostic value of HOXC6 and HOXC8 in the group treated with surgery alone and the group treated with neoadjuvant chemotherapy. Multivariate analysis demonstrated that HOXC6 and HOXC8 expressions were independent prognostic factors in patients with ESCC. CONCLUSIONS: The HOXC6 and HOXC8 genes can be used as prognostic markers in patients with ESCC, but prospective studies are still needed to confirm.

The identification of the ATR inhibitor VE-822 as a therapeutic strategy for enhancing cisplatin chemosensitivity in esophageal squamous cell carcinoma.

Inducing DNA damage is known to be one of the mechanisms of cytotoxic chemotherapy agents for cancer such as cisplatin. The endogenous DNA damage response confers chemoresistance to these agents by repairing DNA damage. The initiation and transduction of the DNA damage response (DDR) signaling pathway, which is dependent on the activation of ATM (ataxia-telangiectasia mutated) and ATR (ataxia telangiectasia and Rad3-related), is essential for DNA damage repair, the maintenance of genomic stability and cell survival. Therefore, ATM or ATR inhibition is considered as a promising strategy for sensitizing cancer cells to chemotherapy. This study is aimed to explore the effect of ATR inhibitor on sensitizing ESCC (esophageal squamous cell carcinoma) cells to cisplatin, and whether ATM deficiency could impact the sensitization. We found that 21.5% of ESCC cases had ATM deficiency and that patients with ATR activation after neoadjuvant chemotherapy had worse chemotherapy response and poorer overall survival than that without ATR activation (32 mons vs. >140mons). Then, it was shown that VE-822 inhibited ATR-CHK1 pathway activation, leading to the accumulation of cisplatin-modified DNA. And it inhibited cell proliferation, induced cell cycle arrest in G1 phase and enhanced cell apoptosis. Moreover, VE-822 significantly sensitized ESCC cells to cisplatin, and these two drugs had synergistic effects, especially in ATM-deficient cells, in vitro and in vivo. Our results suggest that ATR inhibition combining with cisplatin is a new strategy for managing patients with ESCC, especially those with ATM-deficiency. However, this is an idea that requires further validation.

Increased HOXC6 expression predicts chemotherapy sensitivity in patients with esophageal squamous cell carcinoma.

Increased expression of homeobox C6 (HOXC6) predicts poor prognosis of patients with esophageal squamous cell carcinoma (ESCC) and promotes ESCC cell proliferation. Additionally, the expression of HOXC6 was upregulated in chemosensitive ESCC cell lines. Therefore, it was hypothesized that HOXC6 may be associated with chemosensitivity of ESCC. Patients with ESCC who underwent neoadjuvant chemotherapy followed by surgery by a single-surgeon team between January 2000 and December 2012 were enrolled in the present study. Pretreatment biopsy specimens and postoperative resection samples were collected. Immunohistochemistry was performed to examine HOXC6 expression, and the association between HOXC6 expression and tumor regression grade (TRG) was analyzed. In cell lines exhibiting stable knockdown of HOXC6, Cell Counting Kit-8 assays were used to evaluate the chemosensitivity of cells to various concentrations of cisplatin and paclitaxel. A total of 51 pretreatment biopsy specimens were assessed, and patients with increased expression of HOXC6 in pretreatment biopsy specimens exhibited higher TRGs. A total of 186 surgical samples were evaluated; HOXC6 was expressed at a decreased level in patients with higher TRG and at a high level in patients with lower TRG. In addition, downregulation of HOXC6 decreased the sensitivity of ESCC cell lines to cisplatin and paclitaxel, resulting in an increased half-maximal inhibitory concentration. Increased expression of HOXC6 prior to treatment was associated with chemosensitivity in ESCC tissues.

Possible prediction of the response of esophageal squamous cell carcinoma to neoadjuvant chemotherapy based on gene expression profiling.

BACKGROUND: Heterogeneous efficacy of neoadjuvant chemotherapy has led to controversies that have limited its application in clinical practice. Thus, we aimed to identify potential biomarkers predicting esophageal squamous cell carcinoma (ESCC) chemo-responsiveness by gene expression profiling. METHODS: CCK8 assay was used to evaluate the growth inhibitory effect of different concentrations of cisplatin and paclitaxel on the ESCC cell lines EC109, KYSE450, KYSE410, KYSE510, and KYSE150 to differentiate between chemosensitive and chemoresistant cell lines. Gene expression profiling and Real-time PCR were applied to analyze and validate the gene expression differences between chemosensitive and chemoresistant cell lines. IHC was conducted to examine the expression of selected target markers MUC4, MUC13, and MUC20 in 186 ESCC resection samples and the relationships between their expression and tumor regression grade was analyzed. Moreover, RNAi was conducted to instantly block the expression of MUC4, MUC13, and MUC20 to observe their influences on chemo-responsiveness. RESULTS: EC109 was found to be relatively sensitive to both cisplatin and paclitaxel, while KYSE410 was relatively resistant to cisplatin, KYSE510 was relatively resistant to paclitaxel. Gene expression profiling analysis showed that 2018 genes were differentially expressed in sensitive cell line compared to resistant cell lines. The expression patterns of MUC4, MUC13, MUC20 were validated. Low expression of MUC4 and MUC20 in resection samples was significantly correlated with better TRG. Blockage of MUC20 and MUC13 decreased the drug-resistance capacity and chemosensitivity, respectively. CONCLUSIONS: MUC4 and MUC20 were identified as potential biomarkers for predicting the efficacy of neoadjuvant chemotherapy in ESCC patients.

Deregulated HOXB7 Expression Predicts Poor Prognosis of Patients with Esophageal Squamous Cell Carcinoma and Regulates Cancer Cell Proliferation In Vitro and In Vivo.

BACKGROUND: We observed abnormal HOXB7 expression in esophageal squamous cell carcinoma (ESCC) previously. This study was to evaluate the prognostic significance of HOXB7 and reveal the potential mechanism. METHODS: Immunohistochemistry was used to confirm the abnormal expression of HOXB7 in ESCC. The prognostic significance of HOXB7 expression was analyzed in two independent cohorts. RNAi was used to establish two stable HOXB7-knockdown cell strains. CCK8 assay, cell growth curve assay, colony formation assay, flow cycle analysis and tumorigenicity assay in nude mice were employed to investigate the effect of HOXB7 on proliferation in vitro and in vivo. RESULTS: Immunohistochemistry confirmed the abnormal expression of HOXB7 in ESCC compared with paracancerous mucosa (18/23 vs. 9/23, p=0.039). HOXB7 expression was positively correlated with the T stage, lymph node metastasis and TNM stage. The median survival of patients with high HOXB7 expression was significantly shorter than that with low expression (45 months vs. 137 months, p = 0.007 for cohort 1; 19 months vs. 34 months, p = 0.001 for cohort 2). Multivariate survival analysis showed that HOXB7 expression was another independent prognostic factor (HR [95% CI] = 0.573 [0.341-0.963], p = 0.036 for cohort 1; HR [95%CI] = 0.543 [0.350-0.844], p = 0.024 for cohort 2). Experiments in vitro and in vivo showed that after knockdown of HOXB7, the proliferation rate dropped, growth rate descended, colony-formation ability reduced, G1-phase arrest occurred and the tumorigenicity reduced remarkably. CONCLUSIONS: HOXB7 could promote cancer cell proliferation and might be an independent prognostic factor for patients with ESCC.

Coexpression of ANXA2, SOD2 and HOXA13 predicts poor prognosis of esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is the main type of esophageal cancer, and is the sixth leading cause of cancer-related mortality among all types of cancers. Previously, we found that the homeobox A13 gene (HOXA13) plays a crucial role in the carcinogenesis of ESCC and both Annexin A2 (ANXA2) and superoxide dismutase 2 (SOD2) were its potential targets. Samples from 258 patients from two independent cohorts were collected. RT-qPCR and immunohistochemistry (IHC) were used to detect the expression levels of HOXA13, ANXA2 and SOD2. Kaplan­Meier survival curve analysis and Cox proportional hazards regression model were employed to determine their prognostic significance. Results showed that ESCC tissues had higher ANXA2 and SOD2 mRNA and protein levels than the non-cancerous tissues. ANXA2 and SOD2 were found to be positively correlated with HOXA13 expression not only at the mRNA level but also at the protein level. In both the study cohort and the validation cohort, the median overall survival time of patients with high expression of HOXA13, ANXA2 and SOD2 was shorter than the survival time of the patients with low expression. The Cox proportional hazards model revealed that both TNM stage and coexpression of HOXA13/ANXA2/SOD2 are independent predictors of overall survival of ESCC patients. In conclusion, the present study demonstrated that ANXA2 and SOD2 are potential target genes of HOXA13 and their coexpression predicts the poor prognosis of ESCC patients.

[Research progress of prognostic protein biomarkers associated with esophagus squamous cell carcinoma].

Esophageal cancer (EC) is one of the common malignant tumors in China. Esophagectomy based on multi-disciplinary principle improves the quality of life and survival of esophageal cancer patients, but a lot of patients will suffer recurrence or metastasis after surgery. TNM stage is the most important factor which affects the prognosis of patients with esophageal cancer. Besides, there are other prognostic factors, such as abnormal expression of the proteins. Exploration of these proteins may provide new clues to improve prognosis in esophageal squamous cell cancer (ESCC). We reviewed the literatures related to abnormal protein expression in ESCC, and tried to elucidate the prognostic value and potential clinical application of these proteins in ESCC.

[Outcome after surgery preserving pharynx and larynx for cervical esophageal cancer].

OBJECTIVE: To evaluate the long-term survival of multidisciplinary treatment based on thoracic surgery for cervical esophageal squamous cell carcinoma. METHODS: The clinical characters and follow-up data of forty-one cervical esophageal cancer patients who accepted multidisciplinary treatment based on surgery with preservation of pharynx and larynx were retrospectively reviewed, and the long-term survival was compared with 480 non-cervical esophageal cancers who accepted surgery in the same period done by the same surgical team. RESULTS: There were 28 males and 13 females with a mean age of 62 years old. In the cervical esophageal cancer group, 30 patients accepted neoadjuvant chemotherapy, 25 patients accepted adjuvant chemotherapy, and 21 patients accepted both. Six patients received postoperative radiation. Four patients underwent exploratory surgery alone, and 37 cases underwent radical surgery and cervical anastomosis. One case died during the perioperative period. The 1-, 3-, 5- and 8-year survival rates were 96.8%, 52.6%, 35.1%, and 35.1% in the 36 patients with cervical esophageal cancer who underwent radical surgery, and were 85.0%, 54.3%, 45.0%, and 36.7% respectively in the 457 non-cervical esophageal cancer patients. There was no significant difference between the cervical group and non-cervical group(P=0.91). CONCLUSION: Cervical esophageal cancer should be treated in a multidisciplinary approach to obtain satisfactory long-term outcomes.

Exploration of target genes of HOXA13 in esophageal squamous cell carcinoma cell line.

Homeobox genes encode transcriptional factors which regulate cell proliferation and differentiation and have been found to be deregulated in many tumors. Previously, we found that the median survival time of patients with ESCC (Esophageal squamous cell carcinoma) expressing HOXA13 was significantly shorter than those with HOXA13-negative ESCC and we also demonstrated that knockdown of HOXA13 blocked cell proliferation in vitro and in vivo. In this study, we examined the protein expression changes after HOXA13 knockdown by 2-dimentional electrophoresis. Forty-five spots were significantly different, among which 24 were down-regulated and 21 were up-regulated after HOXA13 knockdown. The proteins from 14 gel-spots were further characterized by MALDI-TOF MS, among which, AnnexinA2, MnSOD and ERAB, are validated by Western Blot analysis. Transcriptional target analysis revealed that HOXA13 regulated several cell signaling pathways that are critically involved in cell proliferation, survival and migration. These results provide an additional support to a hypothesis that HOXA13 might participate in the carcinogenesis of ESCC.

[Up-regulation of HOXA13 in esophageal squamous cell carcinoma of stage IIa and its effect on the prognosis].

OBJECTIVE: To investigate the expression of HOXA13 gene in stage-II(a esophageal squamous cell carcinoma(ESCC), and to evaluate its relationship with clinicopathological characteristics and prognosis. METHODS: The expression of HOXA13 was examined by immunohistochemistry(IHC) in specimens from 39 patients with ESCC of stage-II(a, who underwent resection from 1995 to 2002. SPSS software was used to analyze the relationship between HOXA13 expression and clinicopathological characteristics and prognosis of patients. RESULTS: The expression of HOXA13 protein was detected in ESCC tissue, and the positive rate was 61.5%. The median survival time of patients without HOXA13 expression(>72 months) was significantly longer than those with HOXA13 expression (24 months)( P=0.023). Multivariate analysis showed that HOXA13 expression was independent predictor of disease-free survival time of patients with ESCC. CONCLUSION: The expression of HOXA13 can be detected in ESCC and is a negative independent predictor of disease-free survival, which implies that HOXA13 might play a role in ESSC, and may be used as a clinical tumor marker of ESCC.

HOXA13 promotes cancer cell growth and predicts poor survival of patients with esophageal squamous cell carcinoma.

Homeobox genes are known to be classic examples of the intimate relationship between embryogenesis and tumorigenesis. Here, we investigated whether inhibition of HOXA13, a member of the homeobox genes, was sufficient to affect the proliferation of esophageal cancer cells in vitro and in vivo, and studied the association between HOXA13 expression and survival of patients with esophageal squamous cell carcinoma (ESCC). HOXA13 expression was permanently knocked down using an RNA interference technique, and cell strain with stable knockdown of HOXA13 protein was established. Colony formation assay showed that the number of colonies in HOXA13 protein-deficient cells was significantly less than that of control cells (P < 0.01). Tumor growth in nude mice showed that the weight and volume of tumors from the HOXA13 knockdown cells was significantly less than that from the control cells (P < 0.01). Then, HOXA13 expression in ESCC specimens and paired noncancerous mucosa was detected by immunohistochemistry, and overexpression of HOXA13 was found to be more pronounced in ESCCs than paired noncancerous mucosa (P < 0.05). Furthermore, the association of HOXA13 expression and disease-free survival time was analyzed in 155 ESCC cases. The median survival time of patients expressing HOXA13 was significantly shorter than HOXA13-negative patients (P = 0.0006). Multivariate analysis indicated that tumor-node-metastasis (TNM) stage and HOXA13 expression were independent predictors of disease-free survival time of patients with ESCC. Our results showed that HOXA13 expression enhanced tumor growth in vitro and in vivo, and was a negative independent predictor of disease-free survival of patients with ESCC.