Epigenetic regulation of protein tyrosine phosphatase PTPN12 in triple-negative breast cancer

QbD assisted development of hyaluronic acid and TPGS incorporated DOX liposome(s): in vitro assessment of cytotoxicity, uptake, ROS, and NF-κB potential on MDA-MB-231 cells

This work aimed to develop Doxorubicin (DOX), D‑alpha‑tocopheryl polyethylene glycol 1000 succinate (TPGS), and hyaluronic acid (HA) liposomal delivery system using the Quality by Design (QbD) methodology. Developed liposomal formulations show sustained release behaviour as compared to free DOX (96.7 ± 1.81% release in 12 h), as indicated by the release kinetics metrics (82.8 ± 2.82% & 69.8 ± 2.25% releases in 72 h of HA-DOX-TPGS-LIPO and DOX-TPGS-LIPO respectively). In vitro cytotoxicity by MTT assay on MDA-MB-231 and MCF-7 breast cancer cells demonstrated that HA-DOX-TPGS-LIPO had significantly higher cytotoxicity and a clear synergistic impact over free drug or DOX-TPGS-LIPO respectively. Higher cell internalization of HA-DOX-TPGS-LIPO was seen in an in vitro cellular uptake assay in contrast to free drug and DOX-TPGS-LIPO investigated by FACS analysis. ROS production was also assessed using 2', 7'-Dichlorofluorescin diacetates (DCFDA) in the FACS study. Upon treatment with HA-DOX-TPGS-LIPO, triple-negative breast cancer (TNBC) cells showed a higher ROS generation than free DOX and DOX-TPGS-LIPO. Moreover, the expression of the NF-κB protein was also analyzed as a possible substitute mechanism for apoptosis. Free DOX treatment resulted in the maximum expression of NF-κB protein, whereas the HA-DOX-TPGS-LIPO formulation showed the minimum expression of NF-κB protein at the same concentration of DOX-TPGS-LIPO. The study suggested that HA-tethered developed liposomal formulation could be an effective tumor treatment and may be a valuable targeted nanocarrier.

Hypomethylating agents as emerging therapeutics for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is recognized as the most aggressive subtype of breast cancer. Epigenetic silencing, such as DNA methylation mediated by DNA methyltransferases (DNMTs) plays key roles in TNBC tumorigenesis. Hypomethylating agents (HMAs) such as azacitidine, decitabine, and guadecitabine are key inhibitors of DNMTs, and accumulating evidence has shown their immunogenicity properties. In this review, the efficacy and anti-tumor immune responses triggered by HMAs in TNBC are presented and discussed. Essentially, overexpression of DNMTs is associated with poor prognosis and reduced TNBC survival rates, and these effects are negated by HMAs. In particular, HMAs could reverse epigenetic silencing of tumor suppressor genes and enhance immune recognition of TNBC cells. Clinical trials of HMAs in TNBCs are limited but early-stage trials indicate that HMAs are safe and tolerable. More clinical studies are required to establish the effectiveness of HMAs against the disease, as supported by preclinical data substantiating their effectiveness especially guadecitabine. Future research should focus on optimizing dosing and exploring combinations with immunotherapies to maximize the potential of HMAs in TNBC treatment.

Emerging targeted therapeutic strategies for the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC), a subtype of breast cancer that lacks expression of oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2), has clinical features including a high degree of invasiveness, an elevated risk of metastasis, tendency to relapse, and poor prognosis. It constitutes around 10-15% of all breast cancer, and having heredity of BRCA1 mutated breast cancer could be a reason for the occurrence of TNBC in women. Overexpression of cellular and molecular targets, i.e. CD44 receptor, EGFR receptor, Folate receptor, Transferrin receptor, VEGF receptor, and Androgen receptor, have emerged as promising targets for treating TNBC. Signalling pathways such as Notch signalling and PI3K/AKT/mTOR also play a significant role in carrying out and managing crucial pro-survival and pro-growth cellular processes that can be utilised for targeted therapy against triple-negative breast cancer. This review sheds light on various targeting strategies, including cellular and molecular targets, signalling pathways, poly (ADP-ribose) polymerase inhibitors, antibody-drug conjugates, and immune checkpoint inhibitors PARP, immunotherapy, ADCs have all found a place in the current TNBC therapeutic paradigm. The role of photothermal therapy (PTT) and photodynamic therapy (PDT) has also been explored briefly.

Protein tyrosine phosphatase non-receptor type 12 suppresses tumor progression in osteosarcoma cells

BACKGROUND

Protein tyrosine phosphatase non-receptor 12 (PTPN12) plays a prominent role in various cancers as a tumor suppressor. However, the expression of PTPN12 and its biological functions in osteosarcoma (OS) remains to be determined.

METHODS

PTPN12 expression in OS was explored in public databases and detected by immunohistochemistry and Western blot. The cell viability was determined by Cell Counting Kit-8 (CCK-8) assay and colony formation. The cell migration and invasion were assessed by the Transwell assay. Flow cytometry analysis was applied to detect cell apoptosis and cell cycle distribution. To investigate the related mechanism, the levels of EGFR and downstream proteins were detected by Western blot.

RESULTS

PTPN12 expression was significantly decreased in OS samples in GEO database and our hospital. OS cell lines in Cancer Cell Line Encyclopedia (CCLE) database and our cultured OS cells also demonstrated low PTPN12 expression. Lentivirus-induced overexpression of PTPN12 significantly inhibited the cell viability, migration and invasion of 143B and U2OS cells. The results of flow cytometry found that PTPN12 overexpression promoted cell apoptosis and induced cell cycle arrest at G1 phase in 143B and U2OS cells. The phosphorylation levels of EGFR and subsequent proteins of the PI3K/AKT and ERK pathways were inactivated as a result of PTPN12 overexpression in OS.

CONCLUSION

PTPN12 plays a tumor suppressive role in OS cells. Restoring of PTPN12 activity may provide new insights for the treatment of this disease.

Anticancer and chemosensitization effects of cannabidiol in 2D and 3D cultures of TNBC: involvement of GADD45α, integrin-α5, -β5, -β1, and autophagy

To date, promising therapy for triple negative breast cancer (TNBC) remains a serious concern clinically because of poor prognosis, resistance, and recurrence. Herein, anti-cancer potential of synthetic cannabidiol (CBD; Purisys, GA; GMP grade) was explored either alone or as a chemosensitizer followed by post-treatment with doxorubicin (DOX) in TNBC (i.e., MDA-MB-231 and MDA-MB-468) cells. In comparison to 2D cultures, CBD showed greater IC₅₀ values in 3D (LDP2 hydrogel based) cultures of MDA-MB-231 (6.26-fold higher) and MDA-MB-468 (10.22-fold higher) cells. Next-generation RNA sequencing revealed GADD45A, GADD45G, FASN, LOX, and integrin (i.e., -α5, -β5) genes to be novelly altered by CBD in MDA-MB-231 cells. CIM-16 plate-based migration assay and western blotting disclosed that CBD induces anti-migratory effects in TNBC cells by decreasing fibronectin, vimentin, and integrins-α5, -β5, and -β1. Western blotting, RT-qPCR, and immunocytochemistry revealed that CBD inhibited autophagy (decreased Beclin1, and ATG-5, -7, and -16) of TNBC cells. CBD pre-treatment increased DOX sensitivity in TNBC cells. CBD pre-treatment accompanied by DOX treatment decreased LOX and integrin-α5, and increased caspase 9 protein respectively in MDA-MB-468 cells.

Comprehensive analysis of PTPN gene family revealing PTPN7 as a novel biomarker for immuno-hot tumors in breast cancer

Background: The non-receptor protein tyrosine phosphatase (PTPN) gene family has been considered to be involved in the oncogenesis and development of multiple cancers. However, its prognostic utility and immunological relevance in breast cancer (BrCa) have not been clarified.

Methods: A transcriptional level interpretation of the expressions and prognostic values was analyzed using the data from The Cancer Genome Atlas (TCGA) cohort. In addition, GO and DAVID pinpoint the functional enrichment of PTPNs. Moreover, the immune correlations of PTPN7 in BrCa and pan-cancer were further investigated based on the TCGA cohort and were testified using the in-house and the Gene Expression Omnibus (GEO) cohorts.

Results: For systematic analysis of the PTPN family, we found that the expression levels of PTPN1, PTPN6, PTPN7, PTPN18, PTPN20, and PTPN22 was promoted in tumor tissues while comparing with paraneoplastic tissues during our study. We further investigated their functions and protein-protein interactions (PPI), and these results strongly suggested that PTPN family was associated with protein dephosphorylation. Next, we performed an immunological relevance analysis and found that PTPN7 was correlated with immune infiltration, suggesting a stronger association of PTPN7 with immuno-hot tumors in BrCa. In addition, results from the in-house cohort confirmed the positive correlation between PTPN7 and PD-L1. The pan-cancer analysis revealed that PTPN7 was related to PD-L1 and CTLA-4 expression in almost all cancer types. Finally, the predictive value of PTPN7 for immunotherapy was significant in two independent GEO cohorts.

Conclusion: In conclusion, this is the first extensive research on the correlation between PTPN family expression and immune characterization in BrCa. As results, PTPN7 expression is associated with immuno-hot tumors and could be a promising predictive biomarker for immunotherapy in not only BrCa but multiple cancers.

PTPN2, A Key Predictor of Prognosis for Pancreatic Adenocarcinoma, Significantly Regulates Cell Cycles, Apoptosis, and Metastasis

Objective

This study conducted a comprehensive analysis of the members of the PTPN family and emphasized the key role of PTPN2 as a potential therapeutic target and diagnostic biomarker in improving the survival rate of PAAD.

Method

Oncomine was used to analyze the pan-cancer expression of the PTPN gene family. The Cancer Genome Atlas (TCGA) data as well as Genotype-Tissue Expression (GTEx) data were downloaded to analyze the expression and prognosis of PTPNs. The diagnosis of PTPNs was evaluated by the experimental ROC curve. The protein-protein interaction (PPI) network was constructed by combining STRING and Cytoscape. The genes of 50 proteins most closely related to PTPN2 were screened and analyzed by GO and KEGG enrichment. The differentially expressed genes of PTPN2 were found by RNA sequencing, and GSEA enrichment analysis was carried out to find the downstream pathways and targets, which were verified by online tools and experiments. Finally, the relationship between PTPN2 and immune cell infiltration in PAAD, and the relationship with immune score and immune checkpoint were studied.

Result

The expression patterns and the prognostic value of multiple PTPNs in PAAD have been reported through bioinformatic analyzes. Among these members, PTPN2 is the most important prognostic signature that regulates the progression of PAAD by activating JAK-STAT signaling pathway. Comparison of two PAAD cell lines with normal pancreatic epithelial cell lines revealed that PTPN2 expression was up-regulated as a key regulator of PAAD, which was associated with poor prognosis. Knockdown of PTPN2 caused a profound decrease in PAAD cell growth, migration, invasion, and induced PAAD cell cycle and apoptosis. In addition, we conducted a series of enrichment analyses to investigate the PTPN2-binding proteins and the PTPN2 expression-correlated genes. We suggest that STAT1 and EGFR are the key factors to regulate PTPN2, which are involved in the progression of PAAD. Meanwhile, the silencing of PTPN2 induced the repression of STAT1 and EGFR expression.

Conclusion

These findings provide a comprehensive analysis of the PTPN family members, and for PAAD, they also demonstrate that PTPN2 is a diagnostic biomarker and a therapeutic target.

A panel of DNA methylation signature from peripheral blood may predict colorectal cancer susceptibility

Background

Differential DNA methylation panel derived from peripheral blood could serve as biomarkers of CRC susceptibility. However, most of the previous studies utilized post-diagnostic blood DNA which may be markers of disease rather than susceptibility. In addition, only a few studies have evaluated the predictive potential of differential DNA methylation in CRC in a prospective cohort and on a genome-wide basis. The aim of this study was to identify a potential panel of DNA methylation biomarkers in peripheral blood that is associated with CRC risk and therefore serve as epigenetic biomarkers of disease susceptibility.

Methods

DNA methylation profile of a nested case-control study with 166 CRC and 424 healthy normal subjects were obtained from the Gene Expression Omnibus (GEO) database. The differentially methylated markers were identified by moderated t-statistics. The DNA methylation panel was constructed by stepwise logistic regression and the least absolute shrinkage and selection operator in the training dataset. A methylation risk score (MRS) model was constructed and the association between MRS and CRC risk assessed.

Results

We identified 48 differentially methylated CpGs sites, of which 33 were hypomethylated. Of these, sixteen-CpG based MRS that was associated with CRC risk (OR = 2.68, 95% CI: 2.13, 3.38, P <  0.0001) was constructed. This association is confirmed in the testing dataset (OR = 2.02, 95% CI: 1.48, 2.74, P <  0.0001) and persisted in both males and females, younger and older subjects, short and long time-to-diagnosis. The MRS also predicted CRC with AUC 0.82 (95% CI: 0.76, 0.88), indicating high accuracy.

Conclusions

Our study has identified a novel DNA methylation panel that is associated with CRC and could, if validated be useful for the prediction of CRC risk in the future.

Berberine inhibits NLRP3 Inflammasome pathway in human triple-negative breast cancer MDA-MB-231 cell

Background

Breast cancer is still the most common malignant tumor that threatens the female’s life in the world, especially triple-negative breast cancer (TNBC), one of the most difficult subtypes. Lack of targeted therapies brings about urgent demand for novel treatments. In this study we aim to investigate the anti-tumor activity of Berberine (BBR), a Chinese plant-derived alkaloid, against the TNBC cell line MDA-MB-231 and elucidate its mechanism referring to anti-inflammation.

Methods

Cell inhibition rate was measured by Cell Proliferation Assay, the cytotoxic effects was detected by Lactate dehydrogenase (LDH) leakage assay, the colony formation and migration potential were evaluated by colony formation assay and wound healing assay, the release of inflammatory cytokines was detected by EMD multifactor detection, and alterations of proteins and genes related to the NLR family pyrin domain containing 3 (NLRP3) inflammasome pathway were analyzed using western blotting and real-time Polymerase Chain Reaction (PCR).

Results

BBR reduce the viability of MDA-MB-231 cells and increased the release of LDH from the cells in a dose-dependent manner, with and inhibition of colony formation potential and migration of the cells. BBR also caused a marked reduction in the secretion of proinflammatory cytokines, Interleukin-1α (IL-1α), Interleukin-1β (IL-1β), Interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Besides, a down-regulated behavior was observed with the expression of P2X purinoceptor 7 (P2X7), NLRP3, pro-caspase-1, apoptosis-associated speck-like protein containing a caspase-activation and recruitment domain (ASC), caspase-1 p20, Interleukin-18 (IL-18), IL-1β proteins and NLRP3, Caspase-1 and ASC mRNAs in the NLRP3 inflammasome cascade.

Conclusions

Our results confirmed that BBR can effectively affect both tumor outgrowth and spontaneous metastasis in TNBC, and that we identified a new mechanism associated with inhibition the NLRP3 inflammasome pathway, suggesting its potential therapeutic relevance in clinical use.

Alarming Burden of Triple-Negative Breast Cancer in India

Breast cancer is the most prevalent cancer among women worldwide. Among the different breast cancer subtypes, triple-negative breast cancer (TNBC), which is more prevalent among younger age women, is the most aggressive form. Numerous clinicopathologic studies performed throughout the world strongly support the utterly poor prognoses and high recurrence rate of TNBC. The present report details a thorough data survey from Google and PubMed on the burden of TNBC worldwide and other associated factors, with special emphasis on its ever increasing incidence among Indian women. Our analysis revealed that the proportion of TNBC ranges from 6.7% to 27.9% in different countries, with the highest reported percentage in India among all, followed by Indonesia, Algeria, and Pakistan. Most of the other countries (Netherlands, Italy, London, Germany) had a TNBC incidence less than the mean level (ie, 15%). The high incidence of TNBC in the Indian population is associated with vivid risk factors, which primarily include lifestyle, deprivation status, obesity, family history, high mitotic indexes, and BRCA1 mutations. The treatment of TNBC is greatly hampered due to the lack of targeted therapies. Hence, it requires earnest attention towards extensive research for the prevention and development of treatment modalities with high efficacy.

MiR-940 Inhibited Cell Growth and Migration in Triple-Negative Breast Cancer

BACKGROUND Breast cancer is the main type of cancer in women, and triple-negative breast cancer (TNBC) is a unique subtype of breast cancer. The expression of miR-940 has been shown to play an important role in various cancers; however, the role of miR-940 in TNBC remains unknown. MATERIAL AND METHODS The expression of miR-940 in TNBC tissues or cells were tested by qRT-PCR; the expression of miR-940 in cells were overexpressed by miR-940 mimics, and suppressed by anti-miR-940. Bioinformatics algorithms from TargetScanHuman were used to predict the target genes of miR-940. The interaction between miR-940 and ZNF24 was confirmed by dual luciferase assays. The protein level was assayed by Western blot. RESULTS TNBC tissues and cells showed lower miR-940 levels. CONCLUSIONS MiR-940 inhibited cellular proliferation and migration in TNBC.

Chinese Herbal Mixture, Tien-Hsien Liquid, Induces G2/M Cycle Arrest and Radiosensitivity in MCF-7 Human Breast Cancer Cells through Mechanisms Involving DNMT1 and Rad51 Downregulation

The Chinese herbal mixture, Tien-Hsien Liquid (THL), has been proven to suppress the growth and invasiveness of cancer cells and is currently regarded as a complementary medicine for the treatment of cancer. Our previous study using acute promyelocytic leukemia cells uncovered its effect on the downregulation of DNA methyltransferase 1 (DNMT1) which is often overexpressed in cancer cells resulting in the repression of tumor suppressors via hypermethylation. Herein, we explored the effects of THL in MCF-7 breast cancer cells that also demonstrate elevated DNMT1. The results show that THL dose-dependently downregulated DNMT1 accompanied by the induction of tumor suppressors such as p21 and p15. THL arrested cell cycle in G2/M phase and decreased the protein levels of cyclin A, cyclin B1, phospho-pRb, and AKT. DNMT1 inhibition was previously reported to exert a radiosensitizing effect in cancer cells through the repression of DNA repair. We found that THL enhanced radiation-induced clonogenic cell death in MCF-7 cells and decreased the level of DNA double-strand break repair protein, Rad51. Our observations may be the result of DNMT1 downregulation. Due to the fact that DNMT1 inhibition is now a mainstream strategy for anticancer therapy, further clinical trials of THL to confirm its clinical efficacy are warranted.

Potential role of targeted therapies in the treatment of triple-negative breast cancer

Breast cancer is the most common cancer type that affects women and is the major cause of morbidity and mortality. Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype and accounts for 10-20% of all breast cancer cases. TNBC is commonly characterized by the absence of estrogen, progesterone, and the Her2/neu receptor and is usually diagnosed by immunohistochemistry. Mutations in the BRCA1 gene, as well as overexpression of oncogenic kinases, such as human epidermal growth factor receptor 2, vascular endothelial growth factor-A, insulin-like growth factor-1 (IGF-1)/IGF-1 receptor, and transforming growth factor-β1, have been found to be correlated with a higher risk of metastasis and poor overall survival in TNBC patients. The current review briefly discusses the various treatment options including chemotherapeutics and targeted therapies that are available currently for the therapy of TNBC patients and highlights their comparative benefits and disadvantages for clinical application.

Functional and therapeutic significance of protein kinase D enzymes in invasive breast cancer

The protein kinase D (PKD) family members, PKD1, PKD2 and PKD3 constitute a family of serine/threonine kinases that are essential regulators of cell migration, proliferation and protein transport. Multiple types of cancers are characterized by aberrant expression of PKD isoforms. In breast cancer PKD isoforms exhibit distinct expression patterns and regulate various oncogenic processes. In highly invasive breast cancer, the leading cause of cancer-associated deaths in females, the loss of PKD1 is thought to promote invasion and metastasis, while PKD2 and upregulated PKD3 have been shown to be positive regulators of proliferation, chemoresistance and metastasis. In this review, we examine the differential expression pattern, mechanisms of regulation and contributions made by each PKD isoform to the development and maintenance of invasive breast cancer. In addition, we discuss the potential therapeutic approaches for targeting PKD in this disease.