Walker 256 tumour cells increase substance P immunoreactivity locally and modify the properties of the blood–brain barrier during extravasation and brain invasion

Abstract

It is not yet known how tumour cells traverse the blood-brain barrier (BBB) to form brain metastases. Substance P (SP) release is a key component of neurogenic inflammation which has been recently shown to increase the permeability of the BBB following CNS insults, making it a possible candidate as a mediator of tumour cell extravasation into the brain. This study investigated the properties of the BBB in the early stages of tumour cell invasion into the brain, and the possible involvement of SP. Male Wistar rats were injected with Walker 256 breast carcinoma cells via the internal carotid artery and euthanised at 1, 3, 6 and 9 days post tumour inoculation. Culture medium-injected animals served as controls at 1 and 9 days. Evidence of tumour cell extravasation across the BBB was first observed at 3 days post-inoculation, which corresponded with significantly increased albumin (p < 0.05) and SP immunoreactivity (p < 0.01) and significantly reduced endothelial barrier antigen labelling of microvessels when compared to culture medium control animals (p < 0.001). By day 9 after tumour cell inoculation, 100 % of animals developed large intracranial neoplasms that had significantly increased albumin in the peri-tumoral area (p < 0.001). The increased SP immunoreactivity and altered BBB properties at 3 days post-inoculation that coincided with early tumour invasion may be indicative of a mechanism for tumour cell extravasation into the brain. Thus, extravasation of tumour cells into the brain to form cerebral metastases may be a SP-mediated process.

NK1 receptor antagonists and dexamethasone as anticancer agents in vitro and in a model of brain tumours secondary to breast cancer

“…It has been reported previously that Walker 256 breast carcinoma cells do not express SP in this model when injected directly into the brain [57]. However, tumours induced from this cell line do show increased SP immunoreactivity in the peritumoral neuropil in two different models of metastatic brain tumours [57,81]. Thus, it is plausible that exogenous SP from the brain microenvironment may exert a stimulatory effect on these tumour cells in vivo.…”

Characterisation of Walker 256 breast carcinoma cells from two tumour cell banks as assessed using two models of secondary brain tumours

“…The selected late time points were determined after a pilot study of tumour burden and animal weight loss for both cell lines. The method for internal carotid artery injection of tumour cells to induce metastatic brain tumour growth has been previously described in detail [45]. Briefly, under 2% isoflurane inhalation anaesthesia via endotracheal tube, a longitudinal skin incision was made to expose the carotid bifurcation.…”

Pertuzumab, trastuzumab and docetaxel reduced the recurrence of brain metastasis from breast cancer: a case report

“…In a rodent model used to determine the mechanism of breast cancer cell extravasation across the BBB, extravasation was observed 3 days after inoculation. Extravasation was observed with concomitant increases in albumin and substance P immunoreactivity, and a significant reduction in endothelial barrier antigen labeling of microvessels [27]. Moreover, the patient here was also initially treated with lapatinib.…”