SENP2 suppresses NF-κB activation and sensitizes breast cancer cells to doxorubicin

SENP2-NDR2-p21 axis modulates lung cancer cell growth

Sentrin/small ubiquitin-like modifier (SUMO)-specific proteases (SENPs) perform pivotal roles in SUMO maturation and recycling, which modulate the balance of SUMOylation/de-SUMOylation and spatiotemporal functions of SUMOylation targets. The malfunction of SENPs often results in cellular dysfunction and various diseases. However, studies rarely investigated the correlation between SENP2 and lung cancer. This study revealed that SENP2 is a required contributor to lung cancer-cell growth and targets nuclear Dbf2-related 2 (NDR2, also known as serine/threonine kinase 38L or STK38L) for de-SUMOylation, which improves NDR2 kinase activity. This condition leads to the instability of downstream target p21 in accelerating the G1/S cell cycle transition and suggests SENP2 as a promising therapeutic target for lung cancer in the future. Specifically, astragaloside IV, an active ingredient of Jinfukang Oral Liquid (JOL, a clinical combination antilung cancer drug approved by the National Food and Drug Administration (FDA) of China), can repress lung cancer-cell growth via the SENP2-NDR2-p21 axis, which provides new insights into the molecular mechanism of JOL for lung cancer treatment.

Sumo-regulatory SENP2 controls the homeostatic squamous mitosis-differentiation checkpoint

Squamous or epidermoid cancer arises in stratified epithelia but also is frequent in the non-epidermoid epithelium of the lung by unclear mechanisms. A poorly studied mitotic checkpoint drives epithelial cells bearing irreparable genetic damage into epidermoid differentiation. We performed an RNA-sequencing gene search to target unknown regulators of this response and selected the SUMO regulatory protein SENP2. Alterations of SENP2 expression have been associated with some types of cancer. We found the protein to be strongly localised to mitotic spindles of freshly isolated human epidermal cells. Primary cells rapidly differentiated after silencing SENP2 with specific shRNAs. Loss of SENP2 produced in synchronised epithelial cells delays in mitotic entry and exit and defects in chromosomal alignment. The results altogether strongly argue for an essential role of SENP2 in the mitotic spindle and hence in controlling differentiation. In addition, the expression of SENP2 displayed an inverse correlation with the immuno-checkpoint biomarker PD-L1 in a pilot collection of aggressive lung carcinomas. Consistently, metastatic head and neck cancer cells that do not respond to the mitosis-differentiation checkpoint were resistant to depletion of SENP2. Our results identify SENP2 as a novel regulator of the epithelial mitosis-differentiation checkpoint and a potential biomarker in epithelial cancer.

Insights into molecular mechanisms of chemotherapy resistance in cancer

Cancer heterogeneity poses a significant hurdle to the successful treatment of the disease, and is being influenced by genetic inheritance, cellular and tissue biology, disease development, and response to therapy. While chemotherapeutic drugs have demonstrated effectiveness, their efficacy is impeded by challenges such as presence of resilient cancer stem cells, absence of specific biomarkers, and development of drug resistance. Often chemotherapy leads to a myriad of epigenetic, transcriptional and post-transcriptional alterations in gene expression as well as changes in protein expression, thereby leading to massive metabolic reprogramming. This review seeks to provide a detailed account of various transcriptional regulations, proteomic changes, and metabolic reprogramming in various cancer models in response to three primary chemotherapeutic interventions, docetaxel, carboplatin, and doxorubicin. Discussing the molecular targets of some of these regulatory events and highlighting their contribution in sensitivity to chemotherapy will provide insights into drug resistance mechanisms and uncover novel perspectives in cancer treatment.

Thymoquinone Nanoparticle Induces Apoptosis and Cell Migration Retardation through Modulating of SUMOylation Process Genes in Breast Cancer Cell Line

Background

Due to the heterogeneity of breast cancer, most advanced-stage patients are resistant to therapy. Disruption of SUMOylation, a post-translational modification, is linked to breast cancer.

Objective

This study aimed to assess the impact of thymoquinone nanoparticles (Liposomal-TQ), an anti-cancer drug, combined with doxorubicin (DXR), the most effective chemotherapeutic drug used to treat breast cancer, on the expression of SENP2 and SENP6, two major components involved in the SUMOylation process, in normal and cancerous breast cell lines.

Materials and Methods

The MCF7 cell line, a breast cancer cell line, and MCF10, a non-tumor epithelial cell line, were separately treated with Liposomal-TQ and DXR. Cell viability and cell migration were assessed using MTT and scratch tests. Apoptosis analysis was performed using annexin-V/PI staining. Gene expression analysis of SENP2 and SENP6 was conducted using quantitative real-time PCR (RT-qPCR). Additionally, the scratch test evaluated the anti-cell migratory effect of Liposomal-TQ.

Results

The findings obtained from RT-qPCR analysis indicated a significant increase in the expression of SENP2 and SENP6 genes in the TQ and DXR treatment groups compared to the control group in MCF7 but not in MCF10 cell lines (p-value < 0.05). Also, after 24 hours of treatment of MCF7 and MCF10 cells with liposomal-TQ, late apoptotic cells were significantly increased compared to the control and liposome groups (p-value < 0.0001) and compared to the control group, both DXR and Liposomal-TQ dramatically reduced the migratory ability of breast cancer cells (p-value = 0.001 and p-value = 0.001, respectively).

Conclusion

Our study indicated that Liposomal-TQ promotes apoptosis in breast cancer cells and inhibits cell migration ability. These findings enhance our understanding of the role of Liposomal-TQ in the carcinogenic activities of SENP2 and SENP6 in the SUMOylation pathway of breast cancer.

NF-κB in Cell Deaths, Therapeutic Resistance and Nanotherapy of Tumors: Recent Advances

The transcription factor nuclear factor-κB (NF-κB) plays a complicated role in multiple tumors. Mounting evidence demonstrates that NF-κB activation supports tumorigenesis and development by enhancing cell proliferation, invasion, and metastasis, preventing cell death, facilitating angiogenesis, regulating tumor immune microenvironment and metabolism, and inducing therapeutic resistance. Notably, NF-κB functions as a double-edged sword exerting positive or negative influences on cancers. In this review, we summarize and discuss recent research on the regulation of NF-κB in cancer cell deaths, therapy resistance, and NF-κB-based nano delivery systems.

RIPK2 promotes the progression of colon cancer by regulating BIRC3-mediated ubiquitination of IKBKG

Colon cancer is a cancer with high morbidity and mortality worldwide. Receptor interacting serine/threonine kinase 2 (RIPK2) has been identified as a proto-oncogene, but its role in colon cancer is largely unknown. Herein, we found that RIPK2 interference could inhibit the proliferation and invasion of colon cancer cells, and promote apoptosis. Baculoviral IAP repeat containing 3 (BIRC3) is an E3 ubiquitin ligase, which was found highly expressed in colon cancer cells. Co-immunoprecipitation (Co-IP) experiments showed that RIPK2 could directly bind with BIRC3. Then, we demonstrated that RIPK2 overexpression promoted the expression of BIRC3, BIRC3 interference could eliminate RIPK2-dependent cell proliferation and invasion, and BIRC3 overexpression rescued the suppressive effect of RIPK2 interference on cell proliferation and invasion. We further identified IKBKG, an inhibitor of nuclear factor kappa B, as a ubiquitination substrate targeted by BIRC3. IKBKG interference could eliminate the inhibitory effect of BIRC3 interference on cell invasion. RIPK2 could promote BIRC3-mediated ubiquitination of IKBKG, inhibit the expression of IKBKG protein, and promote the expression of NF-κB subunits p50 and p65 proteins. In addition, DLD-1 cells transfected with sh-RIPK2 or/and sh-BIRC3 were injected into mice to establish a tumor xenograft model, and we found that administration of sh-RIPK2 or sh-BIRC3 impeded the growth of xenograft tumors in vivo, and co-administration displayed a better inhibitory effect. In general, RIPK2 promotes the progression of colon cancer by promoting BIRC3-mediated ubiquitination of IKBKG and activating the NF-κB signaling pathway.

The deubiquitinating enzyme STAMBP is a newly discovered driver of triple-negative breast cancer progression that maintains RAI14 protein stability

Triple-negative breast cancer (TNBC) is a heterogeneous malignancy in women. It is associated with poor prognosis, aggressive malignant behavior, and limited treatment options. In the ubiquitin‒proteasome system (UPS), deubiquitinases (DUBs) are potential therapeutic targets for various tumors. In this study, by performing unbiased siRNA screening, we identified STAMBP, a JAMM metalloprotease in the DUB family, as a driver of human TNBC tumor growth. Functionally, the knockdown of STAMBP inhibited the proliferation, migration, and invasion of multiple TNBC cell lines. Immunoprecipitation-mass spectrometry combined with functional and morphological analysis verified the interaction between STAMBP and the actin-binding protein RAI14. Mechanistically, STAMBP stabilized the RAI14 protein by suppressing the K48-linked ubiquitination of RAI14 and thus prevented its proteasomal degradation. Therefore, knocking down STAMBP resulted in the reduction in RAI14 protein levels and suppression of tumor growth in vitro and in vivo. Importantly, high levels of STAMBP were correlated with poor prognosis in TNBC patients. In summary, we reveal a previously unrecognized DUB pathway that promotes TNBC progression and provides a rationale for potential therapeutic interventions for the treatment of TNBC.

Nogo-B receptor increases glycolysis and the paclitaxel resistance of estrogen receptor-positive breast cancer via the HIF-1α-dependent pathway

Chemotherapy can improve the prognosis and overall survival of breast cancer patients, but chemoresistance continues a major problem in clinical. Most breast cancer is estrogen receptor (ER) positive but responds less to neoadjuvant or adjuvant chemotherapy than ER-negative breast cancer. The Nogo-B receptor (NgBR) increases the chemoresistance of ER-positive breast cancer by facilitating oncogene signaling pathways. Here, we further investigated the potential role of NgBR as a novel target to overcome glycolysis-dependent paclitaxel resistance in ER-positive breast cancer. NgBR knockdown inhibited glycolysis and promoted paclitaxel-induced apoptosis by attenuating HIF-1α expression in ER-positive breast cancer cells via NgBR-mediated estrogen receptor alpha (ERα)/hypoxia-inducible factor-1 alpha (HIF-1α) and nuclear factor-kappa B subunit (NF-κB)/HIF-1α signaling pathways. A ChIP assay further confirmed that NgBR overexpression not only facilitates ERα binding to HIF-1α and GLUT1 genes but also promotes HIF-1α binding to GLUT1, HK2, and LDHA genes, which further promotes glycolysis and induces paclitaxel resistance. In conclusion, our study suggests that NgBR expression is essential for maintaining the metabolism and paclitaxel resistance of ER-positive breast cancer, and the NgBR can be a new therapeutic target for improving chemoresistance in ER-positive breast cancer.

Cancer-Associated Dysregulation of Sumo Regulators: Proteases and Ligases

SUMOylation is a post-translational modification that has emerged in recent decades as a mechanism involved in controlling diverse physiological processes and that is essential in vertebrates. The SUMO pathway is regulated by several enzymes, proteases and ligases being the main actors involved in the control of sumoylation of specific targets. Dysregulation of the expression, localization and function of these enzymes produces physiological changes that can lead to the appearance of different types of cancer, depending on the enzymes and target proteins involved. Among the most studied proteases and ligases, those of the SENP and PIAS families stand out, respectively. While the proteases involved in this pathway have specific SUMO activity, the ligases may have additional functions unrelated to sumoylation, which makes it more difficult to study their SUMO-associated role in cancer process. In this review we update the knowledge and advances in relation to the impact of dysregulation of SUMO proteases and ligases in cancer initiation and progression.

SUMOylation and NEDDylation in Primary and Metastatic Cancers to Bone

Post-translational modifications comprise series of enzymatically-driven chemical modifications, virtually involving the entire cell proteome, that affect the fate of a target protein and, in turn, cell activity. Different classes of modifications can be established ranging from phosphorylation, glycosylation, ubiquitination, acetylation, methylation, lipidation and their inverse reactions. Among these, SUMOylation and NEDDylation are ubiquitin-like multi-enzymatic processes that determine the bound of SUMOs and NEDD8 labels, respectively, on defined amino acidic residues of a specific protein and regulate protein function. As fate-determinants of several effectors and mediators, SUMOylation and NEDDylation play relevant roles in many aspects of tumor cell biology. Bone represents a preferential site of metastasis for solid tumors (e.g., breast and prostate cancers) and the primary site of primitive tumors (e.g., osteosarcoma, chondrosarcoma). Deregulation of SUMOylation and NEDDylation affects different aspects of neoplastic transformation and evolution such as epithelial-mesenchymal transition, adaptation to hypoxia, expression and action of tumor suppressors and oncogenic mediators, and drug resistance. Thereby, they represent potential therapeutic targets. This narrative review aims at describing the involvement and regulation of SUMOylation and NEDDylation in tumor biology, with a specific focus on primary and secondary bone tumors, and to summarize and highlight their potentiality in diagnostics and therapeutic strategies.

SENP2 Reduces Hepatocellular Carcinoma Stemness and Improves Sorafenib Sensitivity Through Inactivating the AKT/GSK3β/CTNNB1 Pathway

Background

Small ubiquitin-like modifier specific peptidase 2 (SENP2) suppresses the progression and chemoresistance of several cancers, while few studies report its role in hepatocellular carcinoma (HCC). This study aimed to evaluate the effect of SENP2 on stemness, sorafenib sensitivity, and downstream pathway in HCC, with validation of its molecular mechanisms by compensation experiment.

Methods

SENP2 was regulated by plasmid transfection; meanwhile, in a compensation experiment, protein kinase B (AKT) was activated by SC79 treatment and β-catenin (CTNNB1) was overexpressed by plasmid transfection. After modification, sorafenib sensitivity was detected by cell counting kit-8 assay; stemness was evaluated by CD133⁺ cell proportion and sphere formation assay.

Results

SENP2 was decreased in HCC cell lines (including Hep3B, Li7, and Huh7) compared with normal human liver epithelial cell lines, which was further reduced in HCC stem cells than in normal HCC cells. Subsequently, SENP2 overexpression inhibited CD133⁺ cell proportion, decreased sphere formation ability, promoted sorafenib sensitivity, suppressed AKT and glycogen synthase kinase-3β (GSK3β) phosphorylation, and reduced CTNNB1 expression in Huh7 and Hep3B cells, while SENP2 knockdown showed the reverse effects. The following compensation experiment revealed that activating AKT or overexpressing CTNNB1 promoted CD133⁺ cell proportion and sphere formation ability but suppressed sorafenib sensitivity in Huh7 and Hep3B cells. Moreover, activating AKT or overexpressing CTNNB1 attenuated the effect of SENP2 overexpression on stemness and sorafenib sensitivity in Huh7 and Hep3B cells.

Conclusion

SENP2 suppresses HCC stemness and increases sorafenib sensitivity through inactivating the AKT/GSK3β/CTNNB1 signaling pathway.

Targeting SUMOylation in cancer

PURPOSE OF REVIEW

In the article, we focus on the role of SUMOylation in tumorigenesis and cancer-related processes, including Epithelial-mesenchymal transition (EMT), metastasis, resistance to cancer therapies, and antitumor immunity. Clinical perspective on small ubiquitin-like modifier (SUMO) inhibitors will be discussed.

RECENT FINDINGS

SUMOylation regulates multiple important biologic functions including gene transcription, DNA damage repair, cell cycle, and innate immunity. The SUMO pathway enzymes are usually elevated in various cancers and linked with cancer progression and poor clinical outcomes for patients. Recent studies have revealed the role of SUMOylation in EMT and metastasis through regulating E-Cadherin and Snail expression. Multiple studies demonstrate SUMOylation is involved with chemoresistance and hormone treatment resistance. Oncogene Myc and SUMOylation machinery regulation has been revealed in pancreatic cancer. SUMOylation is involved in regulating antitumor immune response through dendritic cells and T cells. A breakthrough has been made in targeting SUMOylation in cancer as first-in-class SUMO E1 inhibitor TAK-981 enters clinical trials.

SUMMARY

SUMOylation plays an important role in tumor EMT, metastasis, therapy resistance, and antitumor immune response. Pharmaceutical inhibition of SUMOylation has become promising clinical therapy to improve the outcome of the existing chemo and immune therapies.

SUMOylation Wrestles With the Occurrence and Development of Breast Cancer

Breast cancer has the highest incidence among cancers and is the most frequent cause of death in women worldwide. The detailed mechanism of the pathogenesis of breast cancer has not been fully elucidated, and there remains a lack of effective treatment methods for the disease. SUMOylation covalently conjugates a large amount of cellular proteins, and affects their cellular localization and biological activity to participate in numerous cellular processes. SUMOylation is an important process and imbalance of SUMOylation results in the progression of human diseases. Increasing evidence shows that numerous SUMOylated proteins are involved in the occurrence and development of breast cancer. This review summarizes a series of studies on protein SUMOylation in breast cancer in recent years. The study of SUMOylated proteins provides a comprehensive understanding of the pathophysiology of breast cancer and provides evolving therapeutic strategies for the treatment of breast cancer.

SUMOylation Regulator-Related Molecules Can Be Used as Prognostic Biomarkers for Glioblastoma

Introduction

SUMOylation is one of the post-translational modifications. The relationship between the expression of SUMOylation regulators and the prognosis of glioblastoma is not quite clear.

Materials and Methods

The single nucleotide variant data, the transcriptome data, and survival information were acquired from The Cancer Genome Atlas, Gene Expression Omnibus, and cBioportal database. Wilcoxon test was used to analyze differentially expressed genes between glioblastoma and normal brain tissues. Gene set enrichment analysis was conducted to find the possible functions. One risk scoring model was built by the least absolute shrinkage and selection operator Cox regression. Kaplain–Meier survival curves and receiver operating characteristic curves were applied to evaluate the effectiveness of the model in predicting the prognosis of glioblastoma.

Results

Single-nucleotide variant mutations were found in SENP7, SENP3, SENP5, PIAS3, RANBP2, USPL1, SENP1, PIAS2, SENP2, and PIAS1. Moreover, UBE2I, UBA2, PIAS3, and SENP1 were highly expressed in glioblastoma, whereas PIAS1, RANBP2, SENP5, and SENP2 were downregulated in glioblastoma. Functional enrichment analysis showed that the SUMOylation regulators of glioblastoma might involve cell cycle, DNA replication, and other functions. A prognostic model of glioblastoma was constructed based on SUMOylation regulator-related molecules (ATF7IP, CCNB1IP1, and LBH). Kaplain–Meier survival curves and receiver operating characteristic curves showed that the model had a strong ability to predict the overall survival of glioblastoma.

Conclusion

This study analyzed the expression of 15 SUMOylation regulators in glioblastoma. The risk assessment model was constructed based on the SUMOylation regulator-related genes, which had a strong predictive ability for the overall survival of patients with glioblastoma. It might provide targets for the study of the relationship between SUMOylation and glioblastoma.

Blockage of AMPK-ULK1 pathway mediated autophagy promotes cell apoptosis to increase doxorubicin sensitivity in breast cancer (BC) cells: an in vitro study

Background

Activation of autophagy flux contributed to resistance of breast cancer (BC) cells to current chemotherapeutic drugs, which seriously limited their therapeutic efficacy and facilitated BC recurrence in clinic. However, the detailed mechanisms are still not fully understood. In the present study, we identified that inactivation of AMPK-ULK1 signaling cascade mediated protective autophagy sensitized BC cells to doxorubicin in vitro.

Methods

Cell counting kit-8 (CCK-8) assay and colony formation assay were performed to evaluate cell proliferation abilities. Trypan blue staining assay was used to examine cell viability, and Annexin V-FITC/PI double staining method was conducted to determine cell apoptosis. The autophagosomes in BC cells were observed and photographed by electronic microscope (EM). Western Blot analysis was employed to examine genes expressions at protein levels.

Results

The parental doxorubicin-sensitive BC (DS-BC) cells were exposed to increasing concentrations of doxorubicin to establish doxorubicin-resistant BC (DR-BC) cells, and the DR-BC cells were much more resistant to high-dose doxorubicin treatment compared to the DS-BC cells. Interestingly, high-dose doxorubicin specifically increased LC3B-II/I ratio, promoted autophagosomes formation and decreased p62 expression levels to facilitate autophagy in DR-BC cells, instead of DS-BC cells, and the autophagy inhibitor 3-methyladenine (3-MA) enhanced the cytotoxic effects of high-dose doxorubicin on DR-BC cells. In addition, we proved that high-dose doxorubicin triggered protective autophagy in DR-BC cells by activating AMPK-ULK1 pathway. Functionally, high-dose doxorubicin increased the expression levels of phosphorylated AMPK (p-AMPK) and ULK1 (p-ULK1) to activate AMPK-ULK1 pathway in DR-BC cells, and the inhibitors for AMPK (compound C) and ULK1 (SBI-0206965) blocked autophagy to promote cell death and slow down cell growth in DR-BC cells treated with high-dose doxorubicin.

Conclusions

Collectively, our in vitro data indicated that blockage of AMPK-ULK1 signaling cascade mediated protective autophagy might be a promising strategy to increase doxorubicin sensitivity for BC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07901-w.

Opposite estrogen effects of estrone and 2-hydroxyestrone on MCF-7 sensitivity to the cytotoxic action of cell growth, oxidative stress and inflammation activity

There are many kinds of estrogens, and endogenous estrogens produce a variety of estrogen metabolites with similar structure but with different physiological effects after metabolism in vivo. Studies have shown that estrone (E1) widely occurs in the environment and animal-derived food. Because of its estrogen effect, E1 can have adverse effects on the human body as an endocrine disruptor. In this study, we found that E1 and 2-hydroxyestrone (2-OH-E1), the hydroxylation metabolite of estrogen, have opposite proliferative effects on breast cancer cells (MCF-7) through cell proliferation experiments and comparison of their effects by molecular docking and detection of ROS, Ca²⁺, and cell pathway proteins. The effects of 2-methoxyestrone (2-MeO-E1) and 16α-hydroxyestrone (16α-OH-E1) on the biochemical and protein levels of MCF-7 were further studied to compare the effects of metabolic sites and modes on estrogen effects. Hydroxylation of E1 at the C2 site weakened the estrogen effect, down-regulated the expression of the mammalian target of rapamycin (mTOR) and protein kinase B (Akt) pathway proteins, inhibited the proliferation of cancer cells, and enhanced anti-oxidative stress and anti-inflammation. Methoxylation at the C2 position also inhibited the expression of inflammatory and oxidative stress pathway proteins but did not greatly affect the estrogen effects. However, hydroxylation on C16 had no significant effect on the biological effects of estrogen. Therefore, the structural changes of estrogen on C2 are important reasons for the different physiological effects of estrogen and its metabolites. Thus, by regulating the gene Cytochrome P450 1B1(CYP1B1), which affects the hydroxylation metabolism of estrogen, and promoting the hydroxylation of estrone at the C2 position, the estrogen effect of estrone can be effectively reduced, thus reducing the harm its poses in food and the environment.

The Function of SUMOylation and Its Role in the Development of Cancer Cells under Stress Conditions: A Systematic Review

Malignant tumors still pose serious threats to human health due to their high morbidity and mortality. Recurrence and metastasis are the most important factors affecting patient prognosis. Chemotherapeutic drugs and radiation used to treat these tumors mainly interfere with tumor metabolism, destroy DNA integrity, and inhibit protein synthesis. The upregulation of small ubiquitin-like modifier (SUMO) is a prevalent posttranslational modification (PTM) in various cancers and plays a critical role in tumor development. The dysregulation of SUMOylation can protect cancer cells from stresses exerted by external or internal stimuli. SUMOylation is a dynamic process finely regulated by SUMOylation enzymes and proteases to maintain a balance between SUMOylation and deSUMOylation. An increasing number of studies have reported that SUMOylation imbalance may contribute to cancer development, including metastasis, angiogenesis, invasion, and proliferation. High level of SUMOylation is required for cancer cells to survive internal or external stresses. Downregulation of SUMOylation may inhibit the development of cancer, making it an important potential clinical therapeutic target. Some studies have already begun to treat tumors by inhibiting the expression of SUMOylation family members, including SUMO E1 or E2. The tumor cells become more aggressive under internal and external stresses. The prevention of tumor development, metastasis, recurrence, and radiochemotherapy resistance by attenuating SUMOylation requires further exploration. This review focused on SUMOylation in tumor cells to discuss its effects on tumor suppressor proteins and oncoproteins as well as classical tumor pathways to identify new insights for cancer clinical therapy.

Resistance and Overcoming Resistance in Breast Cancer

The incidence and mortality of breast cancer (BC) have increased in recent years, and BC is the main cause of cancer-related death in women worldwide. One of the most significant clinical problems in the treatment of patients with BC is the development of therapeutic resistance. Therefore, elucidating the molecular mechanisms involved in drug resistance is critical. The therapeutic decision for the management of patients with BC is based not only on the assessment of prognostic factors but also on the evaluation of clinical and pathological parameters. Although this has been a successful approach, some patients relapse and/or eventually develop resistance to treatment. This review is focused on recent studies on the possible biological and molecular mechanisms involved in both response and resistance to treatment in BC. Additionally, emerging treatments that seek to overcome resistance and reduce side effects are also described. A greater understanding of the mechanisms of action of treatments used in BC might contribute not only to the enhancement of our understanding of the mechanisms involved in the development of resistance but also to the optimization of the existing treatment regimens.

Comprehensive in silico analysis for identification of novel candidate target genes, including DHX36, OPA1, and SENP2, located on chromosome 3q in head and neck cancers

BACKGROUND

Major milestones of head and neck carcinogenesis have been associated with various genetic abnormalities; however, a clear picture of the molecular networks deregulated during the carcinogenesis of head and neck squamous cell carcinoma (HNSC) has not yet completely revealed.

METHODS

In this study, we used in silico tools and online data sets to evaluate the underlying reasons for the expressional changes of genes residing within the chromosome 3q and to help understanding their contributions to HNSC carcinogenesis.

RESULTS

We found that 13 of 20 most upregulated genes in HNSC are localized to 3q. Further analysis revealed a gene signature consisting of DHX36, OPA1, and SENP2, which showed significant correlation in HNSC samples and potentially be deregulated through similar mechanisms including DNA amplification, transcriptional, and posttranscriptional regulation.

CONCLUSIONS

Considering our findings, we suggest DHX36, OPA1, and SENP2 genes as overexpressed in HNSC tumors and that might be concurrently involved in HNSC carcinogenesis, tumor progression, and induction of angiogenic pathways.

Development and Validation of a Five-immune Gene Pair Signature in Endometrial Carcinoma

BACKGROUND

Endometrial cancer (EC) is a common gynecological malignancy worldwide. Immunity is closely related to the occurrence and prognosis of EC. At the same time, immune-related genes have great potential as prognostic markers in many types of cancer.

OBJECTIVE

Therefore, we attempt to develop immune-related gene markers to enhance prognosis prediction of EC.

METHODS

542 samples of EC gene expression data and clinical follow-up information were downloaded from The Cancer Genome Atlas (TCGA). The samples were randomly divided into two groups, one group as a training set (N=271), and one set as a validation set. (N=271). In the training set, the gene pairs were established based on the relative expression levels of 271 immune genes, and the prognosis-related gene pairs were screened. The lasso was used to select the features, and finally, the robust biomarkers were screened. Finally, the prognostic model of the immune gene pair was established and verified by the validation data set.

RESULTS

10030 immune gene pair (IRGPs) were obtained, and univariate survival analysis was used to identify 1809 prognostic-related IRGPs (p<0.05). 5-IRGPs were obtained by lasso regression feature selection, and multivariate regression was used to establish 5-IRGPs signature, 5-IRGPs signature is an independent prognostic factor for EC patients, and could be risk stratified in patients with TCGA datasets, age, ethnicity, stage, and histological classification (p<0.05). The mean AUC of survival in both the training set and the validation set was greater than 0.7, indicating that 5-IRGPs signature has superior classification performance in patients with EC. In addition, 5-IRGPs have the highest average C index (0.795) compared to the prognostic characteristics of the three endometrial cancers reported in the past and Stage and Age.

CONCLUSION

This study constructed a 5-IRGPs signature as a novel prognostic marker for predicting survival in patients with EC.

Silencing of SENP2 in Multiple Myeloma Induces Bortezomib Resistance by Activating NF-κB Through the Modulation of IκBα Sumoylation

The proteasome inhibitor bortezomib is the most successfully applied chemotherapeutic drug for treating multiple myeloma. However, its clinical efficacy reduced due to resistance development. The underlying molecular mechanisms of bortezomib resistance are poorly understood. In this study, by combining in silico analysis and sgRNA library based drug resistance screening assay, we identified SENP2 (Sentrin/SUMO-specific proteases-2) as a bortezomib sensitive gene and found its expression highly downregulated in bortezomib resistant multiple myeloma patient's samples. Furthermore, down regulation of SENP2 in multiple myeloma cell line RPMI8226 alleviated bortezomib induced cell proliferation inhibition and apoptosis, whereas, overexpression of SENP2 sensitized these cells to bortezomib treatment. We further demonstrate that knockdown of SENP2 in RPMI8226 cells increased SUMO2 conjugated IκBα that resulted in the activation of NF-κB. Taken together, we report that silencing of SENP2 and consequent activation of NF-κB through the modulation of IκBα sumoylation as a novel mechanism inducing bortezomib resistance in multiple myeloma.