Taxane resistance in prostate cancer mediated by AR-independent GATA2 regulation of IGF2

ATRX is a predictive marker for endocrinotherapy and chemotherapy resistance in HER2-/HR+ breast cancer through the regulation of the AR, GLI3 and GATA2 transcriptional network

Drug resistance in breast cancer (BC) is a clinical challenge. Exploring the mechanism and identifying a precise predictive biomarker for the drug resistance in BC is critical. Three first-line drug (paclitaxel, doxorubicin and tamoxifen) resistance datasets in BC from GEO were merged to obtain 1,461 differentially expressed genes for weighted correlation network analysis, resulting in identifying ATRX as the hub gene. ATRX is a chromatin remodelling protein, therefore, ATRX-associated transcription factors were explored, thereby identifying the network of AR, GLI3 and GATA2. GO and KEGG analyses revealed immunity, transcriptional regulation and endocrinotherapy/chemotherapy resistance were enriched. Moreover, CIBERSORT revealed immunity regulation was inhibited in the resistance group. ssGSEA showed a significantly lower immune status in the ATRX-Low group compared to the ATRX-High group. Furthermore, the peaks of H3K9me3 ChIP-seq on the four genes were higher in normal tissues than in BC tissues. Notably, the frequency of ATRX mutation was higher than BRCA in BC. Moreover, depressed ATRX revealed worse overall survival and disease-free survival in the human epidermal growth factor receptor 2 (HER2)-/hormone receptor (HR)+ BC. Additionally, depressed ATRX predicted poor results for patients who underwent endocrinotherapy or chemotherapy in the HER2-/HR+ BC subgroup. A nomogram based on ATRX, TILs and ER exhibited a significantly accurate survival prediction ability. Importantly, overexpression of ATRX significantly inhibited the IC50 of the three first-line drugs on MCF-7 cell. Thus, ATRX is an efficient predictive biomarker for endocrinotherapy and chemotherapy resistance in HER2-/HR+ BC and acts by suppressing the AR, GLI3 and GATA2 transcriptional network.

The emerging role of cross-resistance between taxanes and AR-targeting therapy in metastatic prostate cancer

Background:

To date, the number of prostate cancer ranked first among newly diagnosed malignant tumors in men from multiple countries. Localized prostate cancer could be controlled by curative therapy. However, for patients with metastatic prostate cancer (mPC), the prognosis is poor. As among first-line treatments of systemic therapies for mPC, docetaxel and androgen receptor (AR)-targeted therapies have been widely used. However, mPC patients inevitably developed resistance to the current therapy. More importantly, there is a cross-resistance between docetaxel-based chemotherapy and AR-targeting therapy during the treatment process, which could impair the overall survival benefits without proper administration.

Objective:

Therefore, it is urgent to elucidate the mechanism of cross-resistance and explore the optimal sequential strategy.

Methods:

Here, in this review, we systematically reviewed and summarised the updated literature on clinical evidence and mechanistic research of treatment resistance in mPC.

Results:

Emerging evidence indicated that AR splice variants, AR overexpression or mutations, AR nuclear translocation, as well as AR signaling reactivation collectively contributed to the cross-resistance. With the current understanding of cross-resistance, multiple solutions are promising for improving the benefits, including refining the sequencing of available therapies for mPC, in combination with potential targeted inhibitors or immune checkpoint inhibitors. Further studies are needed to explore the combination of emerging strategies and eventually control the progression of prostate cancer.

Conclusions:

This review defined the mutual and unique resistant mechanism of these treatments, which might help to focus and accelerate therapeutic research that may ultimately improve clinical outcomes for patients with prostate cancer.

Level of evidence:

Not applicable

A comprehensive gene expression profile analysis of prostate cancer cells resistant to paclitaxel and the potent target to reverse resistance

Background: Paclitaxel resistance is the major clinical obstacle in the chemotherapy of prostate cancer (PCa), but the resistant mechanism is less investigated.Purpose: To establish two paclitaxel-resistant PCa cells, provide a comprehensive gene expression profile analysis of resistant cells and the potential target to reverse resistance.Methods: Two Paclitaxel-resistant PCa cells (PC3/PR, LNcap/PR) were established by gradually increasing drug concentration. MTT and transwell assays were performed to detect drug sensitivity, cell proliferation and migration abilities. RNA-Sequencing (RNA-seq) and bioinformatic analyses were performed to identify abnormally expressed genes (AEGs) in resistant cells, and annotate the biological functions of AEGs. The role of the candidate AEG, TLR-4, on the resistant phenotypes was further investigated.Results: The resistance index of resistant cells was 2-3, and they showed a slower proliferation and increased migration ability. 4741 AEGs were screened out (Log2fold change absolute: log2FC(abs)  > 1) in the resistant cells, and they were enriched in 2'-5'-oligoadenylate synthetase activity and chemical carcinogenesis. A number of AEGs, CCND2, IGFBP3, FOS, SHH, ZEB2, and members of FGF, FGFR and WNT families were also identified to be involved in cancer- and resistant phenotype-related processes. Finally, TLR-4 was validated significantly increased in resistant cells, and knockdown of TLR-4 increased drug-sensitivity, inhibited the proliferation and migration abilities.Conclusions: The study provided a comprehensive gene expression profile of paclitaxel-resistant PCa cells, and TLR-4 could be a potential target to reverse paclitaxel resistance.

Transcriptional dysregulation of TRIM29 promotes colorectal cancer carcinogenesis via pyruvate kinase-mediated glucose metabolism

Targeted molecular therapy is the most effective treatment for cancer. An effective therapeutic target for colorectal cancer (CRC) is urgently needed. However, the mechanisms of CRC remain poorly understood, which has hampered research and development of CRC-targeted therapy. TRIM29 is a ubiquitin E3 ligase that has been reported as an oncogene in several human tumors. In this study, we show that increased levels of TRIM29 were detected in CRC compared with normal tissues and were associated with poor clinical outcome, advanced stage and lymph node metastasis, particularly those with right-sided colorectal cancer (RSCC). Notably, GATA2 (GATA Binding Protein 2) transcriptionally repressed TRIM29 expression. The loss of GATA2 and high expression of TRIM29 occur more frequently in RSCC than in left-sided colorectal cancer (LSCC). Functional assays revealed that TRIM29 promotes the malignant CRC phenotype in vitro and in vivo. Mechanistic analyses indicate that TRIM29 promotes pyruvate kinase (mainly PKM1) degradation via the ubiquitin-proteasome pathway. TRIM29 directly targets PKM1 to reduce PKM1/PKM2 ratio, which results in PKM2-mediated aerobic glycolysis (Warburg effect) acting as the dominant energy source in CRC. Our findings suggest that TRIM29 acts as a tumor promoter in CRC, especially in RSCC, and is a potential therapeutic target for CRC treatment.

Mechanisms of docetaxel resistance in prostate cancer: The key role played by miRNAs

One of the main problems with the treatment of metastatic prostate cancer is that, despite an initial positive response, the majority of patients develop resistance and progress. In particular, the resistance to docetaxel, the gold standard therapy for metastatic prostate cancer since 2010, represents one of the main factors responsible for the failure of prostate cancer therapy. According to the present knowledge, different processes contribute to the appearance of docetaxel resistance and non-coding RNA seems to play a relevant role in them. In this review, a comprehensive overview of the miRNA network involved in docetaxel resistance is described, highlighting the pathway/s affected by their activity.

Targeting dormant tumor cells to prevent cancer recurrence

Over the years, developments in oncology led to significantly improved clinical outcome for cancer patients. However, cancer recurrence after initial treatment response still poses a major challenge, as it often involves more aggressive, metastatic disease. The presence of dormant cancer cells is associated with recurrence, metastasis, and poor clinical outcome, suggesting that these cells may play a crucial role in the process of disease relapse. Cancer cell dormancy typically presents as growth arrest while retaining proliferative capacity and can be induced or reversed by a wide array of cell-intrinsic and cell-extrinsic factors. Conventional therapies preferentially target fast-dividing cells, leaving dormant cancer cells largely insensitive to these treatments. In this review, we discuss the role of dormant cancer cells in cancer recurrence and highlight how novel therapy strategies based on cell-cycle modulation, modifications of existing drugs, or enhanced drug-delivery vehicles may be used to specifically target this subpopulation of tumor cells, and thereby have the potential to prevent disease recurrence.

Identification of Long Non-Coding RNA Expression Profiles and Co-Expression Genes in Thyroid Carcinoma Based on The Cancer Genome Atlas (TCGA) Database

Background

Thyroid carcinoma is a malignancy with high morbidity and mortality. Genetic alterations play pivot roles in the pathogenesis of thyroid carcinoma, where long noncoding RNA (lncRNA) have been identified to be crucial. This study sought to investigate the biological functions of lncRNA expression profiles in thyroid carcinoma.

Material/Methods

The lncRNAs expression profiles were acquired from The Cancer Genome Atlas (TCGA) database according to 510 thyroid cancer tissues and 58 normal thyroid tissues. By using R package edgeR, differentially expressed RNAs were obtained. Also, an overall survival model was established based on Cox regression and clinical data then testified by Kaplan-Meier plot, receiver operating characteristic (ROC)-curve and C-index analysis. We investigated the co-expressed genes with lncRNAs involved in the prognostic model, as well as Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was conducted R package clusterProfile.

Results

A total of 352 lncRNAs were identified as differentially expressed in thyroid carcinoma, and an overall survival model consisting of 8 signature lncRNAs was proposed (ROC=0.862, C-index=0.893, P<0.05), 3 of which (DOCK9-DT, FAM111A-DT, and LINC01736) represent co-expressed mRNAs. However, as an oncogene, only FAM111A-DT increased the prognostic risk in thyroid carcinoma. Furthermore, we found differential genes LINC01016, LHX1-DT, IGF2-AS, ND MIR1-1HG-AS1, significantly related to lymph node metastasis (P<0.05).

Conclusions

In this study, we clarified the differential lncRNA expression profiles which were related to the tumorigenesis and prognosis in thyroid carcinoma. Our results provide new rationale and understandings to the pathogenesis and regulatory mechanisms of thyroid carcinoma.

Reverse of microtubule-directed chemotherapeutic drugs resistance induced by cancer-associated fibroblasts in breast cancer

PURPOSE

This study was designed to expound the underlying mechanism of microtubule-directed chemotherapeutic drugs resistance induced by cancer-associated fibroblasts (CAFs) in breast cancer.

MATERIALS AND METHODS

We collected 10 microtubule-directed chemotherapeutic drugs resistant breast tumor samples and 10 normal breast tumor samples to analyze the CAFs distribution by immunohistochemistry and flow cytometry. We also detected the collagen expression in CAFs by real-time PCR. We detected the activation of PI3K/AKT signaling pathway in tumor cells by Western blotting and immunofluorescence. The subcutaneous 4T1/MCF-7 bearing mice were used to investigate the anticancer effects of integrin β1 inhibitor combined with microtubule-directed chemotherapeutic drugs.

RESULTS

In our studies, accumulation of CAFs was observed in tumor samples from microtubule-directed chemotherapeutic drugs resistant patients. Those isolated CAFs could efficiently induce the acquisition of microtubule-directed chemotherapeutic drugs resistance in breast cancer cells. More importantly, we found that CAFs could regulate the microtubule-directed chemotherapeutic drugs resistance through the secretion of collagen to activate the integrin β1/PI3K/AKT signaling pathway. Combination of integrin α2β1 inhibitor and paclitaxel/vincristine sulfate could efficiently overcome the microtubule-directed chemotherapeutic drugs resistance induced by CAFs and enhanced the anticancer effects of chemotherapy in subcutaneous 4T1/MCF-7 bearing mice.

CONCLUSION

Our results demonstrated that CAFs constitute a supporting niche for cancer drug resistance acquisition. Thus, traditional microtubule-directed chemotherapeutic drugs combined with integrin β1 inhibitor may present an innovative therapeutic strategy for breast cancer therapy.

Bioinformatic identification of candidate biomarkers and related transcription factors in nasopharyngeal carcinoma

Background

The incidence of nasopharyngeal carcinoma (NPC) is rare, but a certain amount of mortality remains in NPC patients. Our study aimed to identify candidate genes as biomarkers for NPC screening, diagnosis, and therapy.

Methods

We investigated two microarray profile datasets GSE64634 and GSE12452 to screen the potential differentially expressed genes (DEGs) in NPC. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the DEGs were also performed. A protein-protein interaction (PPI) network of DEGs was constructed by STRING and visualized by Cytoscape software. The associated transcriptional factor regulatory network of the DEGs was also constructed.

Results

A total of 152 DEGs were identified from the GSE64634 and GSE12452 datasets, including 10 upregulated and 142 downregulated genes. Gene functional enrichment analysis indicated that these DEGs were enriched in the cilium movement, antimicrobial humoral response, O-glycan processing, mucosal immune response, carbohydrate transmembrane transporter activity, hormone biosynthetic process, neurotransmitter biosynthetic process, and drug metabolism-cytochrome P450 pathway. Five hub genes (DNALI1, RSPH4A, RSPH9, DNAI2, and ALDH3A1) and one significant module (score = 5.6) were obtained from the PPI network. Key transcriptional factors, such as SPI1, SIN3B, and GATA2, were identified with close interactions with these five hub DEGs from the gene-transcriptional factor network.

Conclusions

With the integrated bioinformatic analysis, numerous DEGs related to NPC were screened, and the hub DEGs we identified may be potential biomarkers for NPC.

Mechanisms of resistance to systemic therapy in metastatic castration-resistant prostate cancer

Patients with metastatic castration-resistant prostate cancer (mCPRC) now have an unprecedented number of approved treatment options, including chemotherapies (docetaxel, cabazitaxel), androgen receptor (AR)-targeted therapies (enzalutamide, abiraterone), a radioisotope (radium-223) and a cancer vaccine (sipuleucel-T). However, the optimal treatment sequencing pathway is unknown, and this problem is exacerbated by the issues of primary and acquired resistance. This review focuses on mechanisms of resistance to AR-targeted therapies and taxane-based chemotherapy. Patients treated with abiraterone, enzalutamide, docetaxel or cabazitaxel may present with primary resistance, or eventually acquire resistance when on treatment. Multiple resistance mechanisms to AR-targeted agents have been proposed, including: intratumoral androgen production, amplification, mutation, or expression of AR splice variants, increased steroidogenesis, upregulation of signals downstream of the AR, and development of androgen-independent tumor cells. Known mechanisms of resistance to chemotherapy are distinct, and include: tubulin alterations, increased expression of multidrug resistance genes, TMPRSS2-ERG fusion genes, kinesins, cytokines, and components of other signaling pathways, and epithelial-mesenchymal transition. Utilizing this information, biomarkers of resistance/response have the potential to direct treatment decisions. Expression of the AR splice variant AR-V7 may predict resistance to AR-targeted agents, but available biomarker assays are yet to be prospectively validated in the clinic. Ongoing prospective trials are evaluating the sequential use of different drugs, or combination regimens, and the results of these studies, combined with a deeper understanding of mechanisms of primary and acquired resistance to treatment, have the potential to drive future treatment decisions in mCRPC.

Skp2 deficiency restricts the progression and stem cell features of castration-resistant prostate cancer by destabilizing Twist

Castration-resistant prostate cancer (CRPC) remains a major clinical challenge because of the lack of effective targeted therapy for its treatment. The mechanism underlying how CRPC gains resistance toward hormone depletion and other forms of chemotherapy is poorly understood. Research on understanding the factors that drive these processes is desperately needed to generate new therapies to cure the disease. Here, we discovered a fundamental role of S-phase protein kinase 2 (Skp2) in the formation and progression of CRPC. In transgenic adenocarcinoma mouse prostate model, Skp2 depletion leads to a profound repression of prostate tumor growth and distal metastasis and substantially prolonged overall survival. We revealed that Skp2 regulates CRPC through Twist-mediated oncogenic functions including epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) acquisitions. Mechanistically, Skp2 interacted with Twist and promoted the non-degradative ubiquitination of Twist. Consequently, Skp2 stabilized Twist protein expression by preventing proteasomal degradation of Twist by β-TrCP. We found that Twist overexpression augments CSC self-renewal and population and that Skp2 inhibition reverts Twist's effects on CSC regulation. Furthermore, genetically depleting or pharmacologically inactivating Skp2 synergistically re-sensitized CRPC cells toward chemotherapies such as paclitaxel or doxorubicin. Together, this study uncovering Skp2-mediated Twist stabilization and oncogenic functions in CRPC offers new knowledge on how CRPC progresses and acquires chemoresistance during tumor progression. It provides proof of principle that Skp2 targeting is a promising approach to combat metastatic CRPC by targeting Twist and CSCs.

Integrated and Functional Genomics Analysis Validates the Relevance of the Nuclear Variant ErbB380kDa in Prostate Cancer Progression

The EGF-family of tyrosine-kinase receptors activates cytoplasmic pathways involved in cell proliferation, migration and differentiation in response to specific extracellular ligands. Beside these canonical pathways, the nuclear localization of the ErbB receptors in primary tumours and cancer cell lines led to investigate their role as transcriptional regulators of cancer genes. The nuclear localization of ErbB3 has been reported in various cancer tissues and cell lines but the nuclear functions and the putative correlation with tumour progression and resistance to therapy remain unclear. We first assessed ErbB3 expression in normal and tumour prostate tissues. The nuclear staining was mainly due to an isoform matching the C-terminus domain of the full length ErbB3_185kDa receptor. Nuclear staining was also restricted to cancer cells and was increased in advanced castration-resistant prostate cancer when compared to localized tumours, suggesting it could be involved in the progression of prostate cancer up to the terminal castration-resistant stage. ChIP-on-chip experiments were performed on immortalized and tumour cell lines selected upon characterization of endogenous nuclear expression of an ErbB3_80kDa isoform. Among the 1840 target promoters identified, 26 were selected before ErbB3_80kDa-dependent gene expression was evaluated by real-time quantitative RT-PCR, providing evidence that ErbB3_80kDa exerted transcriptional control on those genes. Some targets are already known to be involved in prostate cancer progression even though no link was previously established with ErbB3 membrane and/or nuclear signalling. Many others, not yet associated with prostate cancer, could provide new therapeutic possibilities for patients expressing ErbB3_80kDa. Detecting ErbB3_80kDa could thus constitute a useful marker of prognosis and response to therapy.

Androgen Receptor Splice Variant 7 and Efficacy of Taxane Chemotherapy in Patients With Metastatic Castration-Resistant Prostate Cancer

IMPORTANCE

We previously showed that detection of androgen receptor splice variant 7 (AR-V7) in circulating tumor cells (CTCs) from men with castration-resistant prostate cancer (CRPC) was associated with primary resistance to enzalutamide and abiraterone therapy, but the relevance of AR-V7 status in the context of chemotherapy is unknown.

OBJECTIVE

To investigate whether AR-V7-positive patients would retain sensitivity to taxane chemotherapy and whether AR-V7 status would have a differential impact on taxane-treated men compared with enzalutamide- or abiraterone-treated men.

DESIGN, SETTING, AND PARTICIPANTS

We examined CTCs for AR-V7 mRNA using a reverse-transcription polymerase chain reaction assay. From January 2013 to July 2014, we prospectively enrolled patients with metastatic CRPC initiating taxane chemotherapy (docetaxel or cabazitaxel) at a single academic institution (Johns Hopkins). Our prespecified statistical plan required a sample size of 36 taxane-treated men.

MAIN OUTCOMES AND MEASURES

We evaluated associations between AR-V7 status and prostate-specific antigen (PSA) response rates, PSA progression-free survival (PSA PFS), and clinical and/or radiographic progression-free survival (PFS). After incorporating updated data from our prior study of 62 patients treated with enzalutamide or abiraterone, we also investigated the interaction between AR-V7 status (positive or negative) and treatment type (taxane vs enzalutamide or abiraterone).

RESULTS

Of 37 taxane-treated patients enrolled, 17 (46%) had detectable AR-V7 in CTCs. Prostate-specific antigen responses were achieved in both AR-V7-positive and AR-V7-negative men (41% vs 65%; P = .19). Similarly, PSA PFS (hazard ratio [HR], 1.7, 95% CI, 0.6-5.0; P = .32) and PFS (HR, 2.7, 95% CI, 0.8-8.8; P = .11) were comparable in AR-V7-positive and AR-V7-negative patients. A significant interaction was observed between AR-V7 status and treatment type (P < .001). Clinical outcomes were superior with taxanes compared with enzalutamide or abiraterone therapy in AR-V7-positive men, whereas outcomes did not differ by treatment type in AR-V7-negative men. In AR-V7-positive patients, PSA responses were higher in taxane-treated vs enzalutamide- or abiraterone-treated men (41% vs 0%; P < .001), and PSA PFS and PFS were significantly longer in taxane-treated men (HR, 0.19 [95% CI, 0.07-0.52] for PSA PFS, P = .001; HR, 0.21 [95% CI, 0.07-0.59] for PFS, P = .003).

CONCLUSIONS AND RELEVANCE

Detection of AR-V7 in CTCs from men with metastatic CRPC is not associated with primary resistance to taxane chemotherapy. In AR-V7-positive men, taxanes appear to be more efficacious than enzalutamide or abiraterone therapy, whereas in AR-V7-negative men, taxanes and enzalutamide or abiraterone may have comparable efficacy. Circulating tumor cell-based AR-V7 detection may serve as a treatment selection biomarker in CRPC.

Cis-regulatory mechanisms governing stem and progenitor cell transitions

Cis-element encyclopedias provide information on phenotypic diversity and disease mechanisms. Although cis-element polymorphisms and mutations are instructive, deciphering function remains challenging. Mutation of an intronic GATA motif (+9.5) in GATA2, encoding a master regulator of hematopoiesis, underlies an immunodeficiency associated with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Whereas an inversion relocalizes another GATA2 cis-element (-77) to the proto-oncogene EVI1, inducing EVI1 expression and AML, whether this reflects ectopic or physiological activity is unknown. We describe a mouse strain that decouples -77 function from proto-oncogene deregulation. The -77(-/-) mice exhibited a novel phenotypic constellation including late embryonic lethality and anemia. The -77 established a vital sector of the myeloid progenitor transcriptome, conferring multipotentiality. Unlike the +9.5(-/-) embryos, hematopoietic stem cell genesis was unaffected in -77(-/-) embryos. These results illustrate a paradigm in which cis-elements in a locus differentially control stem and progenitor cell transitions, and therefore the individual cis-element alterations cause unique and overlapping disease phenotypes.