Operative and Therapeutic Advancements in Breast Cancer Metastases to the Brain

Local Treatment in Addition to Endocrine Therapy in Hormone Receptor-Positive and HER2-Negative Oligometastatic Breast Cancer Patients: A Retrospective Multicenter Analysis

BACKGROUND

Recent trials have provided robust evidence demonstrating that endocrine therapy with/without targeted therapy, such as cyclin-dependent kinase 4/6 inhibitors or mTOR (mammalian target of rapamycin) inhibitors, effectively halts disease progression in hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer. We investigated the survival impact of local treatment of metastases as a first-line treatment after metastasis in HR-positive and HER2-negative breast cancer patients with a very low metastatic volume.

MATERIALS AND METHODS

From a retrospectively constructed database for three institutes, we identified HR-positive and HER2-negative breast cancer patients with recurrent distant oligometastatic disease after initially curative treatment. De novo stage 4 patients were excluded, and only those with recurrent metastatic disease were included. Oligometastatic disease was defined as follows: (1) ≤2 metastatic lesions in a single organ, (2) a maximal diameter ≤3 cm, and (3) organ involvement, including the lung, liver, adrenal gland, bone, or distant lymph nodes. Local treatment comprised surgery or radiotherapy. Progression-free survival (PFS) and overall survival (OS) were investigated.

RESULTS

Forty-nine patients were included; 33 underwent local treatment. Of these 33 patients, 5 underwent surgical resection and 27 received radiotherapy. One patient underwent both surgical resection and radiotherapy. Median PFS was significantly longer among the patients with local treatment than among the patients without local treatment (30.0 vs. 18.0 months, p = 0.049). In multivariate analysis, local treatment was shown to prolong PFS. However, median OS after metastasis did not differ with regard to local treatment (72.3 vs. 91.0 months, p = 0.272).

CONCLUSION

We showed that local treatment could positively affect disease progression in HR-positive and HER2-negative oligometastatic breast cancer.

PTEN expression by an oncolytic herpesvirus directs T-cell mediated tumor clearance

Engineered oncolytic viruses are used clinically to destroy cancer cells and have the ability to boost anticancer immunity. Phosphatase and tensin homolog deleted on chromosome 10 loss is common across a broad range of malignancies, and is implicated in immune escape. The N-terminally extended isoform, phosphatase and tensin homolog deleted on chromosome 10 alpha (PTENα), regulates cellular functions including protein kinase B signaling and mitochondrial adenosine triphosphate production. Here we constructed HSV-P10, a replicating, PTENα expressing oncolytic herpesvirus, and demonstrate that it inhibits PI3K/AKT signaling, increases cellular adenosine triphosphate secretion, and reduces programmed death-ligand 1 expression in infected tumor cells, thus priming an adaptive immune response and overcoming tumor immune escape. A single dose of HSV-P10 resulted in long term survivors in mice bearing intracranial tumors, priming anticancer T-cell immunity leading to tumor rejection. This implicates HSV-P10 as an oncolytic and immune stimulating therapeutic for anticancer therapy.

Oncolytic viruses are a promising therapeutic approach for cancer treatment. The authors demonstrate the efficacy of an engineered HSV-1 expressing PTENα as an oncolytic and immune stimulating therapy against brain cancer metastases.

Isomangiferin, a Novel Potent Vascular Endothelial Growth Factor Receptor 2 Kinase Inhibitor, Suppresses Breast Cancer Growth, Metastasis and Angiogenesis

Purpose

Vascular endothelial growth factor (VEGF) signal transduction mainly depends on its binding to VEGF receptor 2 (VEGFR-2). VEGF downstream signaling proteins mediate several of its effects in cancer progression, including those on tumor growth, metastasis, and blood vessel formation. The activation of VEGFR-2 signaling is a hallmark of and is considered a therapeutic target for breast cancer. Here, we report a study of the regulation of the VEGFR-2 signaling pathway by a small molecule, isomangiferin.

Methods

A human breast cancer xenograft mouse model was used to investigate the efficacy of isomangiferin in vivo. The inhibitory effect of isomangiferin on breast cancer cells and the underlying mechanism were examined in vitro.

Results

Isomangiferin suppressed tumor growth in xenografts. In vitro, isomangiferin treatment inhibited cancer cell proliferation, migration, invasion, and adhesion. The effect of isomangiferin on breast cancer growth was well coordinated with its suppression of angiogenesis. A rat aortic ring assay revealed that isomangiferin significantly inhibited blood vessel formation during VEGF-induced microvessel sprouting. Furthermore, isomangiferin treatment inhibited VEGF-induced proliferation of human umbilical vein endothelial cells and the formation of capillary-like structures. Mechanistically, isomangiferin induced caspase-dependent apoptosis of breast cancer cells. Furthermore, VEGF-induced activation of the VEGFR-2 kinase pathway was down-regulated by isomangiferin.

Conclusion

Our findings demonstrate that isomangiferin exerts anti-breast cancer effects via the functional inhibition of VEGFR-2. Pharmaceutically targeting VEGFR-2 by isomangiferin could be an effective therapeutic strategy for breast cancer.