Role of B7-H4 siRNA in Proliferation, Migration, and Invasion of LOVO Colorectal Carcinoma Cell Line

The advent of RNA-based therapeutics for metabolic syndrome and associated conditions: a comprehensive review of the literature

Metabolic syndrome (MetS) is a prevalent and intricate health condition affecting a significant global population, characterized by a cluster of metabolic and hormonal disorders disrupting lipid and glucose metabolism pathways. Clinical manifestations encompass obesity, dyslipidemia, insulin resistance, and hypertension, contributing to heightened risks of diabetes and cardiovascular diseases. Existing medications often fall short in addressing the syndrome's multifaceted nature, leading to suboptimal treatment outcomes and potential long-term health risks. This scenario underscores the pressing need for innovative therapeutic approaches in MetS management. RNA-based treatments, employing small interfering RNAs (siRNAs), microRNAs (miRNAs), and antisense oligonucleotides (ASOs), emerge as promising strategies to target underlying biological abnormalities. However, a summary of research available on the role of RNA-based therapeutics in MetS and related co-morbidities is limited. Murine models and human studies have been separately interrogated to determine whether there have been recent advancements in RNA-based therapeutics to offer a comprehensive understanding of treatment available for MetS. In a narrative fashion, we searched for relevant articles pertaining to MetS co-morbidities such as cardiovascular disease, fatty liver disease, dementia, colorectal cancer, and endocrine abnormalities. We emphasize the urgency of exploring novel therapeutic avenues to address the intricate pathophysiology of MetS and underscore the potential of RNA-based treatments, coupled with advanced delivery systems, as a transformative approach for achieving more comprehensive and efficacious outcomes in MetS patients.

Non-coding RNAs in Precursor Lesions of Colorectal Cancer: Their Role in Cancer Initiation and Formation

Colorectal cancer (CRC) is one of the world's most common types of malignancy. The proliferation of precancerous lesions causes this type of cancer. Two distinct pathways for CRC carcinogenesis have been identified: the conventional adenoma-carcinoma pathway and the serrated neoplasia pathway. Recently, evidence has demonstrated the regulatory roles of noncoding RNAs (ncRNAs) in the initiation and progression of precancerous lesions, especially in the adenoma-carcinoma pathway and serrated neoplasia pathway. By expanding the science of molecular genetics and bioinformatics, several studies have identified dysregulated ncRNAs that function as oncogenes or tumor suppressors in cancer initiation and formation by diverse mechanisms via intracellular signaling pathways known to act on tumor cells. However, many of their roles are still unclear. This review summarizes the functions and mechanisms of ncRNAs (such as long non-coding RNAs, microRNAs, long intergenic non-coding RNAs, small interfering RNAs, and circRNAs) in the initiation and formation of precancerous lesions.

Targeted Therapy of B7 Family Checkpoints as an Innovative Approach to Overcome Cancer Therapy Resistance: A Review from Chemotherapy to Immunotherapy

It is estimated that there were 18.1 million cancer cases worldwide in 2018, with about 9 million deaths. Proper diagnosis of cancer is essential for its effective treatment because each type of cancer requires a specific treatment procedure. Cancer therapy includes one or more approaches such as surgery, radiotherapy, chemotherapy, and immunotherapy. In recent years, immunotherapy has received much attention and immune checkpoint molecules have been used to treat several cancers. These molecules are involved in regulating the activity of T lymphocytes. Accumulated evidence shows that targeting immune checkpoint regulators like PD-1/PD-L1 and CTLA-4 are significantly useful in treating cancers. According to studies, these molecules also have pivotal roles in the chemoresistance of cancer cells. Considering these findings, the combination of immunotherapy and chemotherapy can help to treat cancer with a more efficient approach. Among immune checkpoint molecules, the B7 family checkpoints have been studied in various cancer types such as breast cancer, myeloma, and lymphoma. In these cancers, they cause the cells to become resistant to the chemotherapeutic agents. Discovering the exact signaling pathways and selective targeting of these checkpoint molecules may provide a promising avenue to overcome cancer development and therapy resistance. Highlights: (1) The development of resistance to cancer chemotherapy or immunotherapy is the main obstacle to improving the outcome of these anti-cancer therapies. (2) Recent investigations have described the involvement of immune checkpoint molecules in the development of cancer therapy resistance. (3) In the present study, the molecular participation of the B7 immune checkpoint family in anticancer therapies has been highlighted. (4) Targeting these immune checkpoint molecules may be considered an efficient approach to overcoming this obstacle.

Phenotypic and Functional Analyses of B7S1 in Ovarian Cancer

Background: Although programmed death (PD) ligand 1 (PD-L1)/PD-1 inhibitors show potent and durable antitumor effects in a variety of tumors, their efficacy in patients with OvCa is modest. Thus, additional immunosuppressive mechanisms beyond PD-L1/PD-1 need to be identified.

Methods: The mRNA expression profiles of OvCa patients were obtained from The Cancer Genome Atlas (TCGA) database. The expression and clinical characteristics of VTCN1 (encoding B7S1) in OvCa were analyzed. The molecular interaction network, Gene Ontology (GO) analysis and Gene set enrichment analysis (GSEA) were used to functionally annotate and predict signaling pathways of VTCN1 in OvCa. Moreover, 32 treatment-naïve patients with OvCa were recruited to assess B7S1 expression. The cytotoxic immune phenotypes in distinct subgroups were analyzed.

Results: B7S1 expression was increased in tumor sections compared with that in normal tissues from OvCa patients at both the mRNA and protein levels. VTCN1 expression was significantly correlated with the mRNA expression levels of several other co-inhibitory immune checkpoints. B7S1 protein was found to be highly expressed in CD45⁺CD68⁺ myeloid cells, whereas its putative receptor was expressed in CD8⁺ tumor-infiltrating lymphocytes (TILs). Furthermore, expression of B7S1 in antigen-presenting cells (APCs) was significantly correlated with the cytolytic function of CD8⁺ TILs. Functional annotations indicated that VTCN1 was involved in regulating T cell-mediated immune responses and participated in the activation of a variety of classic signaling pathways related to the progression of human cancer.

Conclusion: In OvCa, B7S1 was highly expressed and may initiate dysfunction of CD8⁺ TILs, which could be targeted for cancer immunotherapy.

Generation of avian-derived anti-B7-H4 antibodies exerts a blockade effect on the immunosuppressive response

For highly conserved mammalian protein, chicken is a suitable immune host to generate antibodies. Monoclonal antibodies have been successfully targeted with immunity checkpoint proteins as a means of cancer treatment; this treatment enhances tumor-specific immunity responses through immunoregulation. Studies have identified the importance of B7-H4 in immunoregulation and its use as a potential target for cancer treatment. High levels of B7-H4 expression are found in tumor tissues and are associated with adverse clinical and pathological characteristics. Using the phage display technique, this study isolated specific single-chain antibody fragments (scFvs) against B7-H4 from chickens. Our experiment proved that B7-H4 clearly induced the inhibition of T-cell activation. Therefore, use of anti-B7-H4 scFvs can effectively block the exhaustion of immunity cells and also stimulate and activate T-cells in peripheral blood mononuclear cells. Sequence analysis revealed that two isolated scFv S2 and S4 have the same VH complementarity-determining regions (CDRs) sequence. Molecule docking was employed to simulate the complex structures of scFv with B7-H4 to analyze the interaction. Our findings revealed that both scFvs employed CDR-H1 and CDR-H3 as main driving forces and had strong binding effects with the B7-H4. The affinity of scFv S2 was better because the CDR-L2 loop of the scFv S2 had three more hydrogen bond interactions with B7-H4. The results of this experiment suggest the usefulness of B7-H4 as a target for immunity checkpoints; the isolated B7-H4-specific chicken antibodies have the potential for use in future cancer immunotherapy applications.

Synthetic antiprotozoal thiazolide drug induced apoptosis in colorectal cancer cells: implications of IL-6/JAK2/STAT3 and p53/caspases-dependent signaling pathways based on molecular docking and in vitro study

Colorectal cancer (CRC) is a global pressing healthcare priority. Dysregulation of the IL6/JAK2/STAT3 and p53/caspase downstreaming pathways are significantly involved in the progression of CRC, and mainly affecting apoptosis. Discovery of new anti-cancer agents is laborious, time consuming, and costly with obvious socioeconomic burden. In the present study, we are proposing new molecular insights on the anti-proliferative and apoptotic therapeutic effects of nitazoxanide (NTZ) on CRC. NTZ is FDA-approved thiazolide antiparasitic agent, which has excellent safety and pharmacokinetic profiles. The molecular docking study revealed that NTZ has better binding affinity and docking score against JAK2 and BCL2 proteins compared to 5-Fluorouracil, which is the standard drug for treatment of CRC. The current in vitro work on a human HCT116 cell line displayed that NTZ had lower IC₅₀ value (11.20 µM) than 5-flurouracil (23.78 µM), and NTZ induced a statistically significant down-regulation of IL6/JAK2/STAT3. NTZ also modulated significantly the p53/caspases-dependent signaling pathways, leading to enhancement of apoptosis and an increase of DNA fragmentation. Moreover, NTZ regulated the Bcl-2 gene family and promoted the loss of mitochondrial function which was depicted by release of cytochrome c (Cyt c), and caspase activation in apoptotic HCT116 cells. Additionally, NTZ was able to reduce the expression of VEGF in CRC cell line, which needs future thorough molecular investigations. In conclusion, our findings provided a novel evidence that NTZ could be a dual potential IL6/JAK2/STAT3 signaling inhibitor and p53/caspases-dependent pathway activator in CRC cell line. These potentials support further exploratory molecular researches targeting the therapeutic roles of NTZ in CRC; individually and simultaneously with current approved chemotherapeutic regimens.

RNA-based therapeutics for colorectal cancer: Updates and future directions

Colorectal cancer (CRC) is one of the most common causes of cancer death worldwide. While standard chemotherapy and new targeted therapy have been improved recently, problems such as multidrug resistance (MDR) and severe side effects remain unresolved. RNAs are essential to all biological processes including cell proliferation and differentiation, cell cycle, apoptosis, activation of tumor suppressor genes, suppression of oncogenes. Therefore, there are various potential approaches to address genetic disease like CRC at the RNA level. In contrast to conventional treatments, RNA-based therapeutics such as RNA interference, antisense oligonucleotides, RNA aptamer, ribozymes, have the advantages of high specificity, high potency and low toxicity. It has gained more and more attention due to the flexibility in modulating a wide range of targets. Here, we highlight recent advances and clinical studies involving RNA-based therapeutics and CRC. We also discuss their advantages and limitations that remain to be overcome for the treatment of human CRC.

B7-H4, a promising target for immunotherapy

The coinhibitory molecule B7-H4, an important member of the B7 family, is abnormally expressed in tumors, inflammation and autoimmune diseases. B7-H4 negatively regulates T cell immune response and promotes immune escape by inhibiting the proliferation, cytokine secretion, and cell cycle of T cells. Moreover, B7-H4 plays an extremely important role in tumorigenesis and tumor development including cell proliferation, invasion, metastasis, anti-apoptosis, etc. In addition, B7-H4 has the other biological functions, such as protection against type 1 diabetes (T1D) and islet cell transplantation. Therefore, B7-H4 has been identified as a novel marker or a therapeutic target for the treatment of tumors, inflammation, autoimmune diseases, and organ transplantation. Here, we summarized the expression profiles, physiological and pathological functions, and regulatory mechanisms of B7-H4, the signaling pathways involved, as well as B7-H4-based immunotherapy.

Downregulation of B7-H4 suppresses tumor progression of hepatocellular carcinoma

B7-H4, as a member of the B7 superfamily, was overexpressed in various types of cancers. However, the effects of B7-H4 on the aggressiveness of HCC and the underlying mechanisms have not yet been fully explored. For this purpose, B7-H4 expression was detected by Flow cytometry and Western blotting, it was highly expressed in several HCC cell lines but not in normal LO2 cell line. Knockdown B7-H4 expression induced HCC cells apoptosis by flow cytometry and colony formation assays and increased several apoptosis-related proteins, including survivin, cleaved caspase-3, cleaved caspase-7, and Bax, while the pro-growth protein survivin was reduced. Then the proliferation and cell cycle were suppressed after treated by siB7-H4. Moreover, the level of B7-H4 was significantly correlated with cell migration. In vivo, intra-tumor injection of siRNA targeting B7-H4 can significantly inhibited the growth of HepG2 cells in nude mice. Finally, regions of interest were manually traced on T1WI, T2WI, DWI and ADC of MR images. ADC values were increased in HCC xenografts after B7-H4 siRNA treatment. These data indicated that downregulation of B7-H4 suppressed the proliferation and migration and promoted apoptosis in vitro and in vivo. Blocking the B7-H4 channel might be a potential therapeutic strategy for HCC.

Targeting siRNA in colorectal cancer therapy: Nanotechnology comes into view

Colorectal cancer (CRC) is known as one of the most important causes of death and mortality worldwide. Although several efforts have been made for finding new therapies, no achievements have been made in this area. Multidrug resistance (MDR) mechanisms are one of the key factors that could lead to the failure of chemotherapy. Moreover, it has been shown that various chemotherapy drugs are associated with several side effects. Hence, it seems that finding new drugs or new therapeutic platforms is required. Among different therapeutic approaches, utilization of nanoparticles (NPs) for targeting a variety of molecules such as siRNAs are associated with good results for the treatment of CRC. Targeting siRNA-mediated NPs could turn off the effects of oncogenes and MDR-related genes. In the current study, we summarized various siRNAs targeted by NPs which could be used for the treatment of CRC. Moreover, we highlighted other routes such as liposome for targeting siRNAs in CRC therapy.

Clinical Value of Combined Determination of Serum B7-H4 with Carcinoembryonic Antigen, Osteopontin, or Tissue Polypeptide-Specific Antigen for the Diagnosis of Colorectal Cancer

Aim

B7-H4 is member of the B7 family that negatively regulates the immune response, which are associated with tumor development and prognosis. The present study is aimed at examining serum B7-H4 expression and exploring its contribution to diagnosis in patients with colorectal cancer.

Methods

We determined serum expressions of B7-H4, carcinoembryonic antigen (CEA), osteopontin (OPN), and tissue polypeptide-specific antigen (TPS) in 59 patients with colorectal cancer and 29 healthy volunteers and analyzed the diagnostic value of B7-H4 combined with CEA, OPN, or TPS detection for colorectal cancer. B7-H4, OPN, and TPS serum expressions were measured by enzyme-linked immunosorbent assay, and CEA was measured by electrochemical luminescence detection.

Results

Serum B7-H4 levels were significantly higher in colorectal cancer patients compared with paired normal controls (P = 0.001). B7-H4 serum level was positively correlated with infiltration depth, tumor masses, and lymph node metastasis (P = 0.004, P = 0.016, and P = 0.0052, respectively). We also detected serum expression of B7-H4 before and after radical resection and showed that B7-H4 levels decreased significantly during the first week postoperation (P = 0.0064). We used receiver operating characteristic (ROC) curve analysis to indicate the potential diagnostic values of these markers. The areas under the ROC curves (AUC) for B7-H4, OPN, TPS, and CEA were 0.867, 0.805, 0.812, and 0.833, respectively. The optimal sensitivity and specificity of B7-H4 for discriminating between colon cancer patients and healthy controls were 88.2% and 86.7%, respectively, using a cut-off of value of 78.89 ng/mL. However, combined ROC analysis using B7-H4 and CEA revealed an AUC of 0.929, with a sensitivity of 98.9% and a specificity of 80.4% for discriminating colon cancer patients from healthy controls.

Conclusions

B7-H4 was highly expressed in the serum in colorectal cancer patients. Detection of B7-H4 plus CEA showed significantly increased sensitivity and specificity for discriminating between colorectal cancer patients and healthy controls compared to individual detection of these markers. Combined detection of serum B7-H4 and CEA may thus have the potential to become a new laboratory method for the early clinical diagnosis and prognostic evaluation of colorectal cancer.

Negative roles of B7-H3 and B7-H4 in the microenvironment of cervical cancer

Although persistent human papilloma virus (HPV) infection exerts a crucial influence on cervical carcinogenesis, other factors are also involved in its development, such as intraepithelial lesions and cervical cancer. B7-H3 and B7-H4, which have been reported to be co-regulatory ligands in the B7 family, had been found to be overexpressed in cervical cancer and correlated with adverse clinicopathological features and poor prognosis in our previous studies. In this study, we sought to explore the effects of B7-H3 and B7-H4 on the cervical microenvironment. Among several immune cytokines, interleukin-10 (IL-10) and transforming growth factor (TGF) β1 stand out as important immunosuppressive factors. Our studies found that IL-10 expression increased with pathological change levels and significantly correlated with cervical cancer differentiation (P < 0.05). TGF-β1 correlated with lymph node metastasis (LNM) (P < 0.01). Expression of B7-H3 and B7-H4 positively correlated with the expression of IL-10 and TGF-β1. After co-culture, we found that overexpression of B7-H3 and B7-H4 in cervical cancer cell lines resulted in activation of the cell cycle and decreased apoptosis of U-937 cells. In addition, the contents of IL-10 and TGF-β1, as well as their protein expression levels, increased in co-culture supernatants in U-937 cells, suggesting regulation by the p-JAK2/STAT3 pathway. The in vivo results demonstrated that with the increasing expression of B7-H3/B7-H4, the expression of IL-10 and TGF-β1 also increased significantly. Overall, the expression of B7-H3 and B7-H4 favored an immunosuppressive microenvironment by promoting the production of IL-10 and TGF-β1, thereby resulting in progression of cervical carcinogenesis.

Assessment of combined expression of B7-H3 and B7-H4 as prognostic marker in esophageal cancer patients

The co-stimulatory ligands of B7-family have been confirmed to play an important role in negatively regulating the T-cell mediated anti-tumor immunity. In addition, these inhibitory molecules are also aberrantly expressed on various human cancers tissues, and significantly associated with cancer progression and patients' poor prognoses. We have previously reported that B7-H3 and B7-H4 ligands are highly expressed in human esophageal cancer tissues. Herein, we tried to further analyze the value of their combined expression on prognostic prediction for esophageal cancer patients. We found that the combined expression of both B7-H3 and B7-H4 could be used as a valuable risk factor for predicting the prognosis of esophageal cancer patients (P=0.003). Moreover the status of these patients with high expression of both B7-H3 and B7-H4, was positively and significantly associated with the tumor invasion depth (P=0.0414) and TNM stage (P=0.0414). The Cox multivariate proportional hazards regression analysis revealed that the tumor size (P=0.007), the TNM stage (P=0.024) and the status of both B7-H3 and B7-H4 high expression (P=0.011), could be used as an independent risk factor for predicting patients' postoperative prognosis, respectively. In conclusion, our data indicated that the combined application of B7-H3 and B7-H4 expression can be effectively used as a prognostic marker in esophageal cancer patients.

B7-H4 promotes tumor growth and metastatic progression in lung cancer by impacting cell proliferation and survival

Aberrant expression of B7-H4 occurs across a broad spectrum of human cancers. The aim of this study was to investigate the key role of B7-H4 during tumorigenesis and metastasis of human lung cancer. Our data showed that the shRNA-mediated disruption of B7-H4 markedly inhibited tumor cell proliferation, invasion and migration, increased cell apoptosis and arrested cell cycle at G0/G1. These changes were accompanied by a marked increase in Bax and caspase-3/caspase-8, but a decrease in Bcl-2, cyclinD1 and activation of AKT. In addition, our shRNA-mediated disruption of B7-H4 led to a marked decrease in tumor growth in the immune-compromised mice. Importantly, B7-H4 was expressed in 53.33% of lung carcinomas from our patient cohort (n = 90), but not in any of adjacent non-cancerous tissues, according to our IHC analyses. In particular, B7-H4 expression appeared to be associated with lymph node metastasis (P = 0.008) and TNM stage (P = 0.012). Taken together, our study demonstrates a strong promoting role of B7-H4 in lung tumor growth, progression and metastasis, and supports its potential as a therapeutic target for the treatment of the disease.

Roles of immune inhibitory molecule B7-H4 in cervical cancer

Recent studies have reported that the immune-regulatory protein B7-H4 is highly expressed in various types of cancer, but little is known concerning its roles in cervical cancer. In the present study, we investigated the expression of B7-H4 in human tissues and serum samples, and explored the effects of B7-H4 on proliferation, apoptosis, migration and invasion of cervical cancer cell lines, including SiHa and HeLa. We found that B7-H4 was mainly located in the cytoplasm of cervical cancer cells as determined by immunofluorescence staining. Serum B7-H4 (sB7-H4) was overexpressed in patients with cervical intraepithelial neoplasia (CIN) and cervical cancer, and the area under the ROC curve (AUC) was 0.955. There was no statistical significance between B7-H4 expression and clinicopathological factors in cervical cancer tissue samples. B7-H4 promoted the proliferation of SiHa and HeLa cells, and protected them from apoptosis, which was related to the upregulation of E7, phosphorylated Rb (pRb), E2F, P16, P21, Bcl-2 and the downregulation of Rb, cleaved PARP and cleaved caspase-3 as determined by western blotting. In addition, B7-H4 increased the ability of cell migration and invasion by targeting angiogenic factors, matrix metalloproteinase (MMP)-2, MMP-9 and vascular endothelial growth factor (VEGF) as determined by RT-PCR. Our findings revealed that B7-H4 has the potential to be a useful prognostic marker. In addition, B7-H4 plays important roles in proliferation, apoptosis, migration and invasion, indicating that B7-H4 can serve as a new therapeutic target for cervical cancer.

Knockdown of the differentially expressed gene TNFRSF12A inhibits hepatocellular carcinoma cell proliferation and migration in vitro

Human hepatocellular carcinoma (HCC) has been reported to be highly insensitive to conventional chemotherapy. In the current study, the Agilent Whole Human Genome Oligo Microarray (4×44 K) was used in order to identify the differentially expressed genes between HCC and adjacent tissues, and the top 22 differentially expressed genes were confirmed through reverse transcription-quantitative polymerase chain reaction. Among the identified differences in gene expression, expression of tumor necrosis factor receptor superfamily member 12A (TNFRSF12A) was markedly higher in HCC tissue than in adjacent tissue. Previous studies have suggested that TNFRSF12A may serve a role in tumor growth and metastasis, thus in the current study, TNFRSF12A was knocked down in the SMMC7721 cell line through siRNA. This demonstrated that cells exhibited reduced reproductive and metastatic capacity ex vivo. Thus, the results of the current study suggest that TNFRSF12A may be a candidate therapeutic target for cancer including HCC, and additional genes that exhibited significantly different expression from normal adjacent tissues require further study.

Bmi-1 promotes the invasion and migration of colon cancer stem cells through the downregulation of E-cadherin

Metastasis and recurrence are the challenges of cancer therapy. Recently, mounting evidence has suggested that cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) are critical factors in tumor metastasis and recurrence. The oncogene, Bmi-1, promotes the development of hematologic malignancies and many solid tumors. The aim of the present study was to elucidate the mechanisms through which Bmi-1 promotes the invasion and migration of colon CSCs (CCSCs) using the HCT116 colon cancer cell line. Sphere formation medium and magnetic‑activated cell sorting were used to enrich and screen the CCSCs. CD133 and CD44 were regarded as markers of CCSCs and they were found to be co-expressed in the HCT116 colon cancer cell line. Colony formation assay, cell proliferation assay and viability assay using the Cell Counting Kit-8, and transplantation assay using nude mice injected with CCSCs were used to examine the CCSCs. The CD133+CD44+ HCT116 cells exhibited greater cloning efficiency, an enhanced proliferative ability, increased cell viability and stronger tumorigenicity; these cells were used as the CCSCs for subsequent experiments. In addition, the invasive and migratory abilities of the CD133+CD44+ HCT116 cells were markedly decreased when Bmi-1 was silenced by small interfering RNA (siRNA). The results of RT-qPCR and western blot analysis suggested that Bmi-1 had a negative effect on E-cadherin expression. On the whole, our findings suggest that Bmi-1 promotes the invasion and migration of CCSCs through the downregulation of E-cadherin, possibly by inducing EMT. Our findings thus indicate that Bmi-1 may be a novel therapeutic target for the treatment of colon cancer.

B7-H4 facilitates proliferation of esophageal squamous cell carcinoma cells through promoting interleukin-6/signal transducer and activator of transcription 3 pathway activation

B7‐H4, one of the costimulatory molecules of the B7 family, has been found to be widely expressed in many kinds of tumor tissues and to play an important part in tumor progression and poor prognosis. However, the role of B7‐H4 in esophageal squamous cell carcinoma (ESCC) cells has not been elucidated. In this study, we found that, compared with normal esophageal tissue, B7‐H4 was highly expressed in three ESCC cell lines, Eca109, TE1, and TE13. B7‐H4 silenced cells suppressed cellular proliferation and colony formation. Additionally, compared with control cells, B7‐H4 silenced cells showed higher apoptosis rates, Bcl‐2 and Survivin upregulation, and BAX downregulation. Further study revealed that B7‐H4 silenced cells also showed reduction in interleukin‐6 (IL‐6) secretion, signal transducer and activator of transcription 3 (STAT3) activation, and p‐STAT3 translocation from cytoplasm to nucleus. Moreover, B7‐H4 depletion inhibited the IL‐6 secretion of control cells but not JAK2/STAT3 inhibitor FLLL32‐treated cells. Interleukin‐6 receptor antagonist tocilizumab did not block the p‐JAK2 or p‐STAT3 downregulation induced by B7‐H4 silence. It was suggested that B7‐H4 silence suppressed IL‐6 secretion through JAK2/STAT3 inactivation. Furthermore, cell proliferation and colony formation were downregulated by tocilizumab in control cells but not in B7‐H4 silenced cells, indicating that IL‐6 upregulation induced by B7‐H4 was necessary for cell growth. On the other hand, B7‐H4 expression was downregulated by tocilizumab. In all, our study provided the first evidence that B7‐H4 facilitated ESCC cell proliferation through promoting IL‐6/STAT3 positive loopback pathway activation.