Carboplatin in the neoadjuvant treatment of triple-negative breast cancer-ready for prime time?

Deubiquitinase OTUD7B Regulates Cell Proliferation in Breast Cancer

PURPOSE

The deubiquitylase OTUD7B plays a facilitates role in lung tumorigenesis through VEGF protein, but its role in breast cancer remains unclear. In the present study, we proposed to explore the role of deubiquitylase OTUD7B in breast cancer.

METHODS

The expression of OTUD7B in breast cancer and adjacent tissues was detected. The role of OTUD7B in cell proliferation and invasion of breast cancer cell lines such as MCF-7 and MDA-MB-453 was explored.

RESULTS

OTUD7B is highly expressed in human breast cancer tissues and its higher expression correlates with better survival of patients. Further mechanistic studies reveal that OTUD7B associates with RASGRF1 and PLCE1 to disrupt RAS signaling pathway. Knockdown of OTUD7B results in decreasing levels of RASGRF1 protein, suppression cell growth and invasion in breast cancer. Collectively, our results reveal a previously unappreciated anti-oncogentic role OTUD7B involved in RAS signaling pathway in breast cancer and indicate that deubiquitylases could induce tumor-suppressing or tumor-promoting activities in a cell- and tissue-dependent context.

Transient splicing inhibition causes persistent DNA damage and chemotherapy vulnerability in triple-negative breast cancer

Triple negative breast cancer (TNBC) is an aggressive type of breast cancer. While most TNBCs are initially sensitive to chemotherapy, a substantial fraction acquires resistance to treatments and progresses to more advanced stages. Here, we identify the spliceosome U2 small nuclear ribonucleoprotein particle (snRNP) complex as a modulator of chemotherapy efficacy in TNBC. Transient U2 snRNP inhibition induces persistent DNA damage in TNBC cells and organoids, regardless of their homologous recombination proficiency. U2 snRNP inhibition pervasively deregulates genes involved in the DNA damage response (DDR), an effect relying on their genomic structure characterized by a high number of small exons. Furthermore, a pulse of splicing inhibition elicits long-lasting repression of DDR proteins and enhances the cytotoxic effect of platinum-based drugs and poly(ADP-ribose) polymerase inhibitors (PARPis) in multiple TNBC models. These findings identify the U2 snRNP as an actionable target that can be exploited to enhance chemotherapy efficacy in TNBCs.

Open questions and controversies in the systemic treatment of breast cancer

PURPOSE OF REVIEW

Personalized therapy has revolutionized our approach to breast cancer (BC). Patient selection strategies and new biomarkers are the basis for increasingly complex diagnostic and therapeutic algorithms. In this short review, we discuss recent developments in breast oncology, focusing on controversial topics with relevance for clinical practice.

RECENT FINDINGS

The use of gene expression signatures to guide adjuvant therapy in hormone receptor-positive tumors and personalized strategies for systemic treatment of early stage HER2-positive disease represent significant advances. Additionally, the current role of platinum salts, immune checkpoint inhibitors, and CDK4/6 inhibitors in the (neo)adjuvant treatment remains controversial, with several ongoing randomized clinical trials exploring their use. In the metastatic disease setting, we identify important unmet needs such as the development of predictive biomarkers and the definition of the ideal sequencing algorithm with the incorporation of innovative agents in all subtypes of BC.

SUMMARY

Advances in understanding the molecular biology and heterogeneity of BC have led to the development of new biomarkers and therapeutic agents that significantly impact current and future clinical practice.

Highlights of the 17th St Gallen International Breast Cancer Conference 2021: customising local and systemic therapies

The 17th edition of the St Gallen International Breast Cancer Conference was held in March 2021 in an entirely virtual mode. More than 3,300 participants took part in this important bi-annual critical review of the ‘state of the art’ in the multidisciplinary care of early-stage breast cancer (BC). Seventy-four experts from all continents discussed and commented on the previously elaborated consensus questions as well as numerous interrogations on early-BC diagnosis and treatment asked by the audience. The theme of this year’s Conference was ‘Customising local and systemic therapies’. This paper summarises the results of the 2021 international panel votes as a quick news update. We discuss the most important issues on genetics, pathology, surgery, radiotherapy and systemic therapies presented and debated throughout the conference. We selected the topics based on applicability into the personalised care of BC patients and focused on questions that have a clear impact on our current clinical practice.