Large-scale genomic sequencing reveals adaptive opportunity of targeting mutated-PI3Kα in early and advanced HER2-positive breast cancer

Application of biomimetic nanovaccines in cancer immunotherapy: A useful strategy to help combat immunotherapy resistance

Breakthroughs in actual clinical applications have begun through vaccine-based cancer immunotherapy, which uses the body's immune system, both humoral and cellular, to attack malignant cells and fight diseases. However, conventional vaccine approaches still face multiple challenges eliciting effective antigen-specific immune responses, resulting in immunotherapy resistance. In recent years, biomimetic nanovaccines have emerged as a promising alternative to conventional vaccine approaches by incorporating the natural structure of various biological entities, such as cells, viruses, and bacteria. Biomimetic nanovaccines offer the benefit of targeted antigen-presenting cell (APC) delivery, improved antigen/adjuvant loading, and biocompatibility, thereby improving the sensitivity of immunotherapy. This review presents a comprehensive overview of several kinds of biomimetic nanovaccines in anticancer immune response, including cell membrane-coated nanovaccines, self-assembling protein-based nanovaccines, extracellular vesicle-based nanovaccines, natural ligand-modified nanovaccines, artificial antigen-presenting cells-based nanovaccines and liposome-based nanovaccines. We also discuss the perspectives and challenges associated with the clinical translation of emerging biomimetic nanovaccine platforms for sensitizing cancer cells to immunotherapy.

Persistence of peripheral CD8 + CD28- T cells indicates a favourable outcome and tumour immunity in first-line HER2-positive metastatic breast cancer

BACKGROUND

The contradictory role of CD8 + CD28- T cells in tumour immunity has been reported, while their biological and clinical significance in HER2-positive metastatic breast cancer (MBC) is still unknown.

METHODS

HER2-positive MBC patients with no prior therapy in the metastatic setting were retrospectively recruited at two medical centres. Peripheral CD8 + CD28- T cells (pTCD8+CD28-) were detected at baseline and following therapeutic intervals. Progression-free survival (PFS) was compared according to pTCD8+CD28- levels. The molecular features of pTCD8+CD28- and its correlation with tumour immunity were also investigated.

RESULTS

A total of 252 patients were enrolled, and the median follow-up time was 29.6 months. pTCD8+CD28- high at baseline has prolonged PFS compared to pTCD8+CD28- low (P = 0.001). Patients who maintained pTCD8+CD28- high had a longer PFS than those who kept pTCD8+CD28- low (P < 0.001). The enhanced pTCD8+CD28- level also indicates a longer PFS compared to pTCD8+CD28- low (P = 0.025). Here, pTCD8+CD28- was demonstrated as an antigen-experienced effector T cell. Higher IL-2 level (P = 0.034) and lower TGF-β level (P = 0.016) in the serum and highly infiltrated CD8 + CD28- T cells (P = 0.037) were also connected to pTCD8+CD28- high.

CONCLUSIONS

High pTCD8+CD28- level is associated with a favourable tumour immunity and a better PFS of HER2-targeting therapy in MBC patients.

Role of the Tumor Microenvironment in Mediating Resistance to Anti-HER2 Antibodies

Breast cancer (BC) is the most common cancer and the second leading cause of cancer-related deaths in women globally. Despite advancements in treatment strategies, many patients still develop challenging-to-treat metastatic disease. The development and progression of tumors are influenced by genetic/epigenetic changes within tumor cells and alterations in the tumor microenvironment (TME) through a dynamic communication. The TME comprises various elements, including immune, tumor, and stromal cells. Tumor cells at the core of the TME orchestrate complex signals that lead to tumor growth, survival, and resistance to treatment. Human epidermal growth factor receptor 2 (HER2) is overexpressed in a significant proportion of invasive breast cancers, influencing prognosis and prediction. Novel therapeutic approaches target HER2-positive breast cancers by leveraging HER2-targeted therapeuirtcs such as antibody-drug conjugates, monoclonal antibodies, and tyrosine kinase inhibitors. The TME in HER2-positive breast cancers also involves cancer-associated fibroblasts and cancer-associated adipocytes, which play critical roles in tumor progression and therapy resistance. The immune microenvironment also plays a significant role, with studies indicating its impact on outcomes in HER2-positive breast cancer. Trastuzumab, one of the first monoclonal antibodies targeting HER2, has shown promise in enhancing survival rates in HER2-overexpressing breast cancer. Integration of trastuzumab with chemotherapy has demonstrated significant enhancements in disease-free survival as well as overall survival rates during early breast cancer treatment. Trastuzumab functions by inhibiting HER2 signaling pathways, leading to cell cycle arrest and induction of apoptosis. Overall, understanding the complex interplay between HER2, the tumor microenvironment, and therapeutic interventions is essential for improving outcomes in HER2-positive BC.

Association of PIK3CA mutation with outcomes in HER2-positive breast cancer treated with anti-HER2 therapy: A meta-analysis and bioinformatic analysis of TCGA‑BRCA data

BACKGROUND

This study aimed to comprehensively explore the clinical significance of PIK3CA mutation in human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with anti-HER2 therapy.

METHODS

We systematically searched PubMed, Embase, and the Cochrane databases for eligible studies assessing the association between PIK3CA mutation and outcomes in patients with HER2-positive breast cancer receiving anti-HER2 therapy. The main outcomes included: (1) pathological complete response (pCR) or disease-free survival (DFS) for the neoadjuvant setting; (2) DFS or invasive DFS for the adjuvant setting; (3) objective response rate (ORR), progression-free survival (PFS), time-to-progression (TTP), or overall survival (OS) for the metastatic setting. The mutational landscape of HER2-positive breast cancer according to PIK3CA mutation status was examined based on TCGA breast cancer dataset.

RESULTS

Totally, 43 eligible studies, covering 11,099 patients with available data on PIK3CA mutation status, were identified. In the neoadjuvant setting, PIK3CA mutation was significantly associated with a lower pCR rate (OR=0.23, 95% CI 0.19-0.27, p<0.001). This association remained significant irrespective of the type of anti-HER2 therapy (single-agent or dual-agent) and hormone receptor status. There were no significant differences in DFS between PIK3CA mutated and wild-type patients in either the neoadjuvant or adjuvant settings. In the metastatic setting, PIK3CA mutation predicted worse ORR (OR=0.26, 95%CI 0.17-0.40, p<0.001), PFS (HR=1.28, 95%CI 1.03-1.59, p = 0.024) and TTP (HR=2.27, 95%CI 1.54-3.34, p<0.001). However, no significant association was observed between PIK3CA mutation status and OS. Distinct mutational landscapes were observed in HER2-positive breast cancer between individuals with PIK3CA mutations and those with wild-type PIK3CA.

CONCLUSIONS

PIK3CA mutation was significantly associated with a lower pCR rate in HER2-positive breast cancer treated with neoadjuvant anti-HER2 therapy. In the metastatic setting, PIK3CA mutation was predictive of worse ORR, PFS and TTP. These results suggest the potential for developing PI3K inhibitors as a therapeutic option for these patients.

HER2-positive breast cancer: cotargeting to overcome treatment resistance

PURPOSE OF REVIEW

The introduction in clinical practice of anti-HER2 agents changed the prognosis of patients with HER2-positive (HER2+) breast cancer in both metastatic and early setting. Although the incomparable results obtained in the last years with the approval of new drugs targeting HER2, not all patients derive benefit from these treatments, experiencing primary or secondary resistance. The aim of this article is to review the data about cotargeting HER2 with different pathways (or epitopes of receptors) involved in its oncogenic signaling, as a mechanism to overcome resistance to anti-HER2 agents.

RECENT FINDINGS

Concordantly to the knowledge of the HER2+ breast cancer heterogeneity as well as new drugs, novel predictive biomarkers of response to anti-HER2 treatments are always raised helping to define target to overcome resistance. Cotargeting HER2 and hormone receptors is the most well known mechanism to improve benefit in HER2+/HR+ breast cancer. Additional HER2-cotargeting, such as, with PI3K pathway, as well as different HERs receptors or immune-checkpoints revealed promising results.

SUMMARY

HER2+ breast cancer is an heterogenous disease. Cotargeting HER2 with other signaling pathways involved in its mechanism of resistance may improve patient outcomes. Research efforts will continue to investigate novel targets and combinations to create more effective treatment regimes.

Clinical Impact of New Treatment Strategies for HER2-Positive Metastatic Breast Cancer Patients with Resistance to Classical Anti-HER Therapies

HER2-positive breast cancer accounts for 15-20% of all breast cancer cases. This subtype is characterized by an aggressive behavior and poor prognosis. Anti-HER2 therapies have considerably improved the natural course of the disease. Despite this, relapse still occurs in around 20% of patients due to primary or acquired treatment resistance, and metastasis remains an incurable disease. This article reviews the main mechanisms underlying resistance to anti-HER2 treatments, focusing on newer HER2-targeted therapies. The progress in anti-HER2 drugs includes the development of novel antibody-drug conjugates with improvements in the conjugation process and novel linkers and payloads. Moreover, trastuzumab deruxtecan has enhanced the efficacy of trastuzumab emtansine, and the new drug trastuzumab duocarmazine is currently undergoing clinical trials to assess its effect. The combination of anti-HER2 agents with other drugs is also being evaluated. The addition of immunotherapy checkpoint inhibitors shows some benefit in a subset of patients, indicating the need for useful biomarkers to properly stratify patients. Besides, CDK4/6 and tyrosine kinase inhibitors are also included in the design of new treatment strategies. Lapitinib, neratinib and tucatinib have been approved for HER2-positive metastasis patients, however clinical trials are currently ongoing to optimize combined strategies, to reduce toxicity, and to better define the useful setting. Clinical research should be strengthened along with the discovery and validation of new biomarkers, as well as a deeper understanding of drug resistance and action mechanisms.

PIK3CA mutations are associated with pathologic complete response rate to neoadjuvant pyrotinib and trastuzumab plus chemotherapy for HER2-positive breast cancer

BACKGROUND

Neoadjuvant treatment with a dual anti-human epidermal growth factor receptor 2 (HER2) blockade with pyrotinib and trastuzumab has been shown to be effective for HER2-positive breast cancer.

METHODS

The genomic characteristics of 425 cancer-related genes from the archived tumour blocks of 50 patients enrolled in a prospective neoadjuvant pyrotinib and trastuzumab plus chemotherapy clinical trial (ChiCTR1900022293) were assessed by next-generation sequencing (NGS). The relationship between tumour biomarkers and the postoperative pathological complete response (pCR) were explored.

RESULTS

Forty-five patients completed neoadjuvant chemotherapy and final surgery, of which 26 (58%) achieved a pCR. Among all driver gene mutations, PIK3CA mutation was screened out for having a significant relationship with the treatment response. The pCR rate of patients with wild-type PIK3CA was significantly higher than patients with mutated PIK3CA (80.8% vs. 26.3%; P = 0.00057), and remained significant after a multiple comparison adjustment (P_adjusted = 0.024). We further evaluated the predictive value with logistic regression model of clinical features, genetic biomarkers or both, an AUC of 0.912 (95% CI: 0.827-0.997) was achieved in the integrated model.

CONCLUSIONS

Our data suggest that HER2-positive breast cancers with activating mutations in PIK3CA are less likely to benefit from pyrotinib combined with trastuzumab neoadjuvant therapy.

Drug-resistant HER2-positive breast cancer: Molecular mechanisms and overcoming strategies

Breast cancer is one of the most common malignancies and the leading cause of cancer-related death in women. HER2 overexpression is a factor for poor prognosis in breast cancer, and anti-HER2 therapy improves survival in these patients. A dual-targeted combination of pertuzumab and trastuzumab, alongside cytotoxic chemotherapy, constitutes the primary treatment option for individuals with early-stage, HER2-positive breast cancer. Antibody-drug conjugate (ADC) and tyrosine kinase inhibitors (TKI) also increase the prognosis for patients with metastatic breast cancer. However, resistance to targeted therapy eventually occurs. Therefore, it is critical to investigate how HER2-positive breast cancer is resistant to targeted therapy and to develop novel drugs or strategies to overcome the resistance simultaneously. This review aims to provide a comprehensive discussion of the HER2-targeted agents currently in clinical practice, the molecular mechanisms of resistance to these drugs, and the potential strategies for overcoming resistance.