Faculty Opinions recommendation of Triple-negative breast cancers - a panoply of cancer types.

Triple-negative breast cancers (TNBC) occur more frequently in younger women and do not express estrogen receptor (ER) nor progesterone receptor (PR), and are therefore often considered hormone-insensitive. Treatment of premenopausal TNBC patients almost always includes chemotherapy, which may lead to premature ovarian insufficiency (POI) and can severely impact quality of life. Hormone replacement therapy (HRT) is contraindicated for patients with a history of hormone-sensitive breast cancer, but the data on safety for TNBC patients is inconclusive, with a few randomized trials showing increased risk-ratios with wide confidence intervals for recurrence after HRT. Here, we review the literature on alternative pathways from the classical ER/PR. We find that for both estrogens and progestogens, potential alternatives exist for exerting their effects on TNBC, ranging from receptor conversion, to alternative receptors capable of binding estrogens, as well as paracrine pathways, such as RANK/RANKL, which can cause progestogens to indirectly stimulate growth and metastasis of TNBC. Finally, HRT may also influence other hormones, such as androgens, and their effects on TNBCs expressing androgen receptors (AR). Concluding, the assumption that TNBC is completely hormone-insensitive is incorrect. However, the direction of the effects of the alternative pathways is not always clear, and will need to be investigated further.

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INPP4B promotes PI3Kα-dependent late endosome formation and Wnt/β-catenin signaling in breast cancer

Nature Communications ◽

10.1038/s41467-021-23241-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Samuel J. Rodgers ◽

Lisa M. Ooms ◽

Viola M. J. Oorschot ◽

Ralf B. Schittenhelm ◽

Elizabeth V. Nguyen ◽

...

Keyword(s):

Breast Cancer ◽

Tumor Growth ◽

Breast Cancer Cells ◽

Triple Negative ◽

Akt Signaling ◽

Late Endosome ◽

Breast Cancers ◽

Lysosomal Degradation ◽

Late Endosomes ◽

Mrna And Protein Expression

AbstractINPP4B suppresses PI3K/AKT signaling by converting PI(3,4)P2 to PI(3)P and INPP4B inactivation is common in triple-negative breast cancer. Paradoxically, INPP4B is also a reported oncogene in other cancers. How these opposing INPP4B roles relate to PI3K regulation is unclear. We report PIK3CA-mutant ER+ breast cancers exhibit increased INPP4B mRNA and protein expression and INPP4B increased the proliferation and tumor growth of PIK3CA-mutant ER+ breast cancer cells, despite suppression of AKT signaling. We used integrated proteomics, transcriptomics and imaging to demonstrate INPP4B localized to late endosomes via interaction with Rab7, which increased endosomal PI3Kα-dependent PI(3,4)P2 to PI(3)P conversion, late endosome/lysosome number and cargo trafficking, resulting in enhanced GSK3β lysosomal degradation and activation of Wnt/β-catenin signaling. Mechanistically, Wnt inhibition or depletion of the PI(3)P-effector, Hrs, reduced INPP4B-mediated cell proliferation and tumor growth. Therefore, INPP4B facilitates PI3Kα crosstalk with Wnt signaling in ER+ breast cancer via PI(3,4)P2 to PI(3)P conversion on late endosomes, suggesting these tumors may be targeted with combined PI3K and Wnt/β-catenin therapies.

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The mitotic checkpoint is a targetable vulnerability of carboplatin-resistant triple negative breast cancers

Scientific Reports ◽

10.1038/s41598-021-82780-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Stijn Moens ◽

Peihua Zhao ◽

Maria Francesca Baietti ◽

Oliviero Marinelli ◽

Delphi Van Haver ◽

...

Keyword(s):

Breast Cancer ◽

Triple Negative ◽

Breast Cancer Subtype ◽

Mitotic Checkpoint ◽

Breast Cancers ◽

Checkpoint Kinases ◽

Xenograft Models ◽

Potential Strategy ◽

Shrna Screen ◽

Resistant Cells

AbstractTriple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype, lacking effective therapy. Many TNBCs show remarkable response to carboplatin-based chemotherapy, but often develop resistance over time. With increasing use of carboplatin in the clinic, there is a pressing need to identify vulnerabilities of carboplatin-resistant tumors. In this study, we generated carboplatin-resistant TNBC MDA-MB-468 cell line and patient derived TNBC xenograft models. Mass spectrometry-based proteome profiling demonstrated that carboplatin resistance in TNBC is linked to drastic metabolism rewiring and upregulation of anti-oxidative response that supports cell replication by maintaining low levels of DNA damage in the presence of carboplatin. Carboplatin-resistant cells also exhibited dysregulation of the mitotic checkpoint. A kinome shRNA screen revealed that carboplatin-resistant cells are vulnerable to the depletion of the mitotic checkpoint regulators, whereas the checkpoint kinases CHEK1 and WEE1 are indispensable for the survival of carboplatin-resistant cells in the presence of carboplatin. We confirmed that pharmacological inhibition of CHEK1 by prexasertib in the presence of carboplatin is well tolerated by mice and suppresses the growth of carboplatin-resistant TNBC xenografts. Thus, abrogation of the mitotic checkpoint by CHEK1 inhibition re-sensitizes carboplatin-resistant TNBCs to carboplatin and represents a potential strategy for the treatment of carboplatin-resistant TNBCs.

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Triple negative aggressive phenotype controlled by miR-135b and miR-365: new theranostics candidates

Scientific Reports ◽

10.1038/s41598-021-85746-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Gloria Bertoli ◽

Claudia Cava ◽

Fabio Corsi ◽

Francesca Piccotti ◽

Cristina Martelli ◽

...

Keyword(s):

Breast Cancer ◽

Cell Lines ◽

Triple Negative ◽

Differentially Expressed ◽

Tumor Control ◽

Breast Cancers ◽

Basal Breast Cancer ◽

Therapeutic Molecules ◽

Invasive Capacity ◽

Tnbc Subtype

AbstractTriple negative breast cancer (TNBC) accounts for about a fifth of all breast cancers and includes a diverse group of cancers. The heterogeneity of TNBC and the lack of target receptors on the cell surface make it difficult to develop specific therapeutic treatments. These aspects cause the high negative prognosis of patients with this type of tumor. The analysis of the molecular profiles of TNBC samples has allowed a better characterization of this tumor, supporting the search for new reliable diagnostic markers. To this end, we have developed a bioinformatic approach to integrate networks of genes differentially expressed in basal breast cancer compared to healthy tissues, with miRNAs able to regulate their expression. We studied the role of these miRNAs in TNBC subtype cell lines. We therefore identified two miRNAs, namely miR-135b and miR-365, with a central role in regulating the altered functional pathways in basal breast cancer. These two miRNAs are differentially expressed in human TNBC immunohistochemistry-selected tissues, and their modulation has been shown to play a role in the proliferation of tumor control and its migratory and invasive capacity in TNBC subtype cell lines. From the perspective of personalized medicine, we managed to modulate the expression of the two miRNAs in organotypic cultures, suggesting their possible use as diagnostic and therapeutic molecules. miR-135b and miR-365 have a key role in TNBC, controlling proliferation and invasion. Their detection could be helpful in TNBC diagnosis, while their modulation could become a new therapeutic tool for TNBC.

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PD-L1 Expression after Neoadjuvant Chemotherapy in Triple-Negative Breast Cancers Is Associated with Aggressive Residual Disease, Suggesting a Potential for Immunotherapy

Cancers ◽

10.3390/cancers13040746 ◽

2021 ◽

Vol 13 (4) ◽

pp. 746

Author(s):

Beatriz Grandal ◽

Manon Mangiardi-Veltin ◽

Enora Laas ◽

Marick Laé ◽

Didier Meseure ◽

...

Keyword(s):

Neoadjuvant Chemotherapy ◽

Triple Negative ◽

Residual Disease ◽

Checkpoint Inhibitors ◽

Rapid Development ◽

Complete Response ◽

Tumor Burden ◽

Small Subset ◽

Breast Cancers ◽

Residual Cancer Burden

The consequences of neoadjuvant chemotherapy (NAC) for PD-L1 activity in triple-negative breast cancers (TNBC) are not well-understood. This is an important issue as PD-LI might act as a biomarker for immune checkpoint inhibitors’ (ICI) efficacy, at a time where ICI are undergoing rapid development and could be beneficial in patients who do not achieve a pathological complete response. We used immunohistochemistry to assess PD-L1 expression in surgical specimens (E1L3N clone, cutoff for positivity: ≥1%) on both tumor (PD-L1-TC) and immune cells (PD-L1-IC) from a cohort of T1-T3NxM0 TNBCs treated with NAC. PD-L1-TC was detected in 17 cases (19.1%) and PD-L1-IC in 14 cases (15.7%). None of the baseline characteristics of the tumor or the patient were associated with PD-L1 positivity, except for pre-NAC stromal TIL levels, which were higher in post-NAC PD-L1-TC-positive than in negative tumors. PD-L1-TC were significantly associated with a higher residual cancer burden (p = 0.035) and aggressive post-NAC tumor characteristics, whereas PD-L1-IC were not. PD-L1 expression was not associated with relapse-free survival (RFS) (PD-L1-TC, p = 0.25, and PD-L1-IC, p = 0.95) or overall survival (OS) (PD-L1-TC, p = 0.48, and PD-L1-IC, p = 0.58), but high Ki67 levels after NAC were strongly associated with a poor prognosis (RFS, p = 0.0014, and OS, p = 0.001). A small subset of TNBC patients displaying PD-L1 expression in the context of an extensive post-NAC tumor burden could benefit from ICI treatment after standard NAC.

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