The cytotoxicity of two recently synthesized triorganotin isothiocyanate derivatives, nuclear retinoid X receptor ligands, was tested and compared in estrogen-receptor-positive MCF 7 and -negative MDA-MB-231 human breast carcinoma cell lines. A 48 h MTT assay indicated that tributyltin isothiocyanate (TBT-ITC) is more cytotoxic than triphenyltin isothiocyanate (TPT-ITC) in MCF 7 cells, and the same trend was observed in the MDA-MB-231 cell line. A comet assay revealed the presence of both crosslinks and increasing DNA damage levels after the 17 h treatment with both derivatives. Differences in cytotoxicity of TBT-ITC and TPT-ITC detected by FDA staining correspond to the MTT data, communicating more pronounced effects in MCF 7 than in the MDA-MB-231 cell line. Both derivatives were found to cause apoptosis, as shown by the mitochondrial membrane potential (MMP) depolarization and caspase-3/7 activation. The onset of caspase activation correlated with MMP dissipation and the total cytotoxicity more than with the amount of active caspases. In conclusion, our data suggest that the DNA damage induced by TBT-ITC and TPT-ITC treatment could underlie their cytotoxicity in the cell lines studied.

Circulating tumor cells (CTCs) and the immune infiltration of tumors are closely related to clinical outcomes. This study aimed to verify the influence of stromal lymphocyte infiltration and the immune context of tumor microenvironment on the hematogenous spread and prognosis of 282 chemotherapy naïve primary BC patients. To detect the presence of mesenchymal CTCs, RNA extracted from CD45-depleted peripheral blood was interrogated for the expression of mesenchymal gene transcripts. Tumor-infiltrating lymphocytes (TILs) were detected in the stromal areas by immunohistochemistry, using CD3, CD8, and CD45RO antibodies. The concentrations of 51 plasma cytokines were measured by multiplex bead arrays. TILs infiltration in mesenchymal CTC-positive patients significantly decreased their progression-free survival (HR = 4.88, 95% CI 2.30–10.37, p < 0.001 for CD3high; HR = 6.17, 95% CI 2.75–13.80, p < 0.001 for CD8high; HR = 6.93, 95% CI 2.86–16.81, p < 0.001 for CD45ROhigh). Moreover, the combination of elevated plasma concentrations of transforming growth factor beta-3 (cut-off 662 pg/mL), decreased monocyte chemotactic protein-3 (cut-off 52.5 pg/mL) and interleukin-15 (cut-off 17.1 pg/mL) significantly increased the risk of disease recurrence (HR = 4.838, 95% CI 2.048–11.427, p < 0.001). Our results suggest a strong impact of the immune tumor microenvironment on BC progression, especially through influencing the dissemination and survival of more aggressive, mesenchymal CTC subtypes.

Vagal activity in patients with metastatic or recurrent breast cancer can predict their survival and it can be altered by behavioral, pharmacological and surgical interventions. Tumor oxygenation is important in defining the cellular metabolic microenvironment of human malignancies, O 2-depleted areas coincide with nutrient and energy deprivation and with a hostile metabolic microenvironment. In our work, we simultaneously measured two oxygen-sensitive parameters in breast cancer patients; blood oxygen saturation (SpO 2) and trans-cutaneous O 2 partial pressure (tcpO 2) in breast tissue. Concurrently, 5-minute beat-to-beat heart rate recording was carried out in order to get heart rate variability (HRV) data from time-domain analyses, frequency-domain analyses and entropy and symbolic dynamic non-linear methods. We compared these parameters in patients newly diagnosed with breast cancer, in patients after therapy and in healthy controls. We found lower tcpO 2 in patients with presence of malignant tumor compared to those post-treatment and/or without presence of malignancy. We also detected lower 2UV% (two unlike variations) and entropy in non-linear HRV analysis in all breast cancer patients and these parameters associated with parasympathetic activity did not return to the values comparable with healthy individuals after anti-cancer therapy, contrary to tcpO 2. Our findings show that breast tissue tcpO 2 can recover after the anti-cancer treatment, but complex heart rate control and cardio-vagal regulation remain impaired. This supports the idea that cancer patients and survivors might benefit from non-pharmacological interventions aimed at enhancing vagal activity, such as HRV biofeedback or Yoga.