Impact of genotypic and phenotypic differences in sarcoma models on the outcome of photochemical internalization (PCI) of bleomycin

Upregulated microRNA-423-5p promotes oxidative stress through targeting glutathione S-transferase mu 1 in asthenozoospermia

The dysregulation of microRNAs (miRNAs) plays an important role in asthenozoospermia. This study evaluated the sperm microRNA-423-5p (miR-423-5p) expression in asthenozoospermia and normozoospermia, exploring the role of miR-423-5p in asthenozoospermia. Eighty participants were divided into asthenozoospermic (AZS, n = 40) and normozoospermic (Norm, n = 40) groups. Fresh semen samples were collected and the sperm cells were separated. Quantitative Real-Time polymerase chain reaction was used to measure the sperm miR-423-5p level. Receiver operating characteristic curve (ROC) was employed to test the diagnostic performance of miR-423-5p in asthenospermia. Dual-reporter luciferase assay was adopted to confirm the target gene of miR-423-5p. The target gene level in asthenozoospermia and normozoospermia was measured, and the biological function of target gene in asthenozoospermia was evaluated. Results showed that the miR-423-5p expression level in the AZS group was higher than that in Norm group, which was positively correlated with the severity of asthenozoospermia. ROC analysis of miR-423-5p showed an area under curve (AUC) of 0.69 (95% confidence interval = 0.57-0.80, p <0 .01), with 80% sensitivity and 60% specificity. Glutathione S-transferase mu 1 (GSTM1) is a target gene of miR-423-5p, which significantly decreased in the AZS group. Compared with Norm group, glutathione S-transferase (GST) activity and total antioxidant capacity (TAC) level decreased, while malondialdehyde (MDA) level increased in the AZS group. Furthermore, GST activity and TAC level were negatively correlated with miR-423-5p expression, while MDA level was positively correlated with miR-423-5p expression. In conclusion, the sperm miR-423-5p level significantly was upregulated in asthenozoospermia. High-level miR-423-5p inhibited sperm motility through targeting GSTM1 to promote oxidative stress.

Silencing KIF18B enhances radiosensitivity: identification of a promising therapeutic target in sarcoma

Background

Sarcomas are rare heterogeneous tumours, derived from primitive mesenchymal stem cells, with more than 100 distinct subtypes. Radioresistance remains a major clinical challenge for sarcomas, demanding urgent for effective biomarkers of radiosensitivity.

Methods

The radiosensitive gene Kinesin family member 18B (KIF18B) was mined through bioinformatics with integrating of 15 Gene Expression Omnibus (GEO) datasets and The Cancer Genome Atlas (TCGA) database. We used radiotherapy-sh-KIF18B combination to observe the anti-tumour effect in sarcoma cells and subcutaneous or orthotopic xenograft models. The KIF18B-sensitive drug T0901317 (T09) was further mined to act as radiosensitizer using the Genomics of Drug Sensitivity in Cancer (GDSC) database.

Findings

KIF18B mRNA was significantly up-regulated in most of the subtypes of bone and soft tissue sarcoma. Multivariate Cox regression analysis showed that KIF18B high expression was an independent risk factor for prognosis in sarcoma patients with radiotherapy. Silencing KIF18B or using T09 significantly improved the radiosensitivity of sarcoma cells, delayed tumour growth in subcutaneous and orthotopic xenograft model, and elongated mice survival time. Furthermore, we predicted that T09 might bind to the structural region of KIF18B to exert radiosensitization.

Interpretation

These results indicated that sarcomas with low expression of KIF18B may benefit from radiotherapy. Moreover, the radiosensitivity of sarcomas with overexpressed KIF18B could be effectively improved by silencing KIF18B or using T09, which may provide promising strategies for radiotherapy treatment of sarcoma.

Fundings

A full list of funding can be found in the Funding Sources section.

Predictive biomarkers for 5-ALA-PDT can lead to personalized treatments and overcome tumor-specific resistances

BACKGROUND

Photodynamic therapy (PDT) is a minimally invasive, clinically approved therapy with numerous advantages over other mainstream cancer therapies. 5-aminolevulinic acid (5-ALA)-PDT is of particular interest, as it uses the photosensitiser PpIX, naturally produced in the heme pathway, following 5-ALA administration. Even though 5-ALA-PDT shows high specificity to cancers, differences in treatment outcomes call for predictive biomarkers to better stratify patients and to also diversify 5-ALA-PDT based on each cancer's phenotypic and genotypic individualities.

AIMS

The present study seeks to highlight key biomarkers that may predict treatment outcome and simultaneously be exploited to overcome cancer-specific resistances to 5-ALA-PDT.

METHODS AND RESULTS

We submitted two glioblastoma (T98G and U87) and three breast cancer (MCF7, MDA-MB-231, and T47D) cell lines to 5-ALA-PDT. Glioblastoma cells were the most resilient to 5-ALA-PDT, while intracellular production of 5-ALA-derived protoporphyrin IX (PpIX) could not account for the recorded PDT responses. We identified the levels of expression of ABCG2 transporters, ferrochelatase (FECH), and heme oxygenase (HO-1) as predictive biomarkers for 5-ALA-PDT. GPX4 and GSTP1 expression vs intracellular glutathione (GSH) levels also showed potential as PDT biomarkers. For T98G cells, inhibition of ABCG2, FECH, HO-1, and/or intracellular GSH depletion led to profound PDT enhancement. Inhibition of ABCG2 in U87 cells was the only synergistic adjuvant to 5-ALA-PDT, rendering the otherwise resistant cell line fully responsive to 5-ALA-PDT. ABCG2 or FECH inhibition significantly enhanced 5-ALA-PDT-induced MCF7 cytotoxicity, while for MDA-MB-231, ABCG2 inhibition and intracellular GSH depletion conferred profound synergies. FECH inhibition was the only synergism to ALA-PDT for the most susceptible among the cell lines, T47D cells.

CONCLUSION

This study demonstrates the heterogeneity in the cellular response to 5-ALA-PDT and identifies biomarkers that may be used to predict treatment outcome. The study also provides preliminary findings on the potential of inhibiting specific molecular targets to overcome inherent resistances to 5-ALA-PDT.

The effects of low irradiance long duration photochemical internalization on glioma spheroids

BACKGROUND

Photodynamic therapy (PDT), if given over extended time periods (i.e. hours or days) and at very low irradiance in the μW/cm² range, has been shown to be more effective than acute PDT (aPDT) administered over minutes. This has led to the concept of metronomic PDT (mPDT), which consists of ultra-low irradiance light illumination for extended periods of time along with either continuous or repetitive delivery of photosensitizer. Since the drug activating technology photochemical internalization (PCI) is based on PDT it seemed reasonable to expect that ultra-low irradiance, if administered over an extended period of time, could nevertheless result in effective metronomic PCI (mPCI) comparable to or more effective than that obtained with relatively high and short irradiance i.e. acute PCI (aPCI).

METHODS

Tumor spheroids consisting of F98 cells were used as in-vitro tumor models. The amphiphilic photosensitizer Al phthalocyanine disulfonate (AlPcS_2a) was used for all PCI experiments. Light treatment was administered from a diode laser at λ=670 nm at various irradiance exposures of 2 mW/cm² for aPCI and 0.05 - 0.2 mW/cm² for mPCI with durations ranging from 3 to 12 min for aPCI and 120 min for mPCI.

RESULTS

AlPcS_2a fluorescence was seen throughout the cytosol following short or long light treatment, corresponding to aPCI and mPCI respectively. Spheroid growth was significantly inhibited or completely suppressed at a mPCI radiance of 0.05 or 0.72 J/cm² respectively, with all bleomycin (BLM) concentrations used, compared to either BLM alone or aPCI at radiant exposure at these levels. The effects of BLM-aPCI and mPCI were comparable at radiance levels of 0.96 and 1.44 J/cm².

CONCLUSIONS

Results show that mPCI could effectively cause significant spheroid growth inhibition with the delivery of extremely low light irradiance rates delivered over an extended period of time. These findings suggest that effective implementation of mPCI can deliver adequate drug efficacy at depths necessary to reach infiltrating glioma cells in the surgical resection cavity wall.

Link between cardiac function and the antioxidative defense mechanism in aged rats

Aging presents profound structural and physiological changes in the cardiovascular system. Oxidative stress, a major contributing factor during the aging process, has been involved in various age-related cardiovascular pathologies. Nevertheless, the underlying mechanism of oxidative stress in the aging heart is still unclear. This study was designed to determine whether changes in cardiac structure and function in aged rats were associated with decreases in the antioxidative defense mechanism. Young (3-month-old) and aged (24-month-old) rats were used in this study, and the differences in function, structure, antioxidative capacity and the expression of antioxidative-related proteins between the two groups were compared. By using echocardiography, we observed that compared to young rats, the left ventricular internal end-diastolic diameter (LVID; d) and left ventricular volume at diastole (LV Vol; d) were significantly increased in aged rats, while the MV E/A (E wave and A wave ratio, the ratio of peak velocity of early to late filling of mitral inflow), which represents heart diastolic function, was significantly decreased in aged rats. In addition, we observed degenerative histological modifications and an increased number of apoptotic cells in aged rats. We further detected the protein expression of catalase (CAT), glutathione synthetase (GSS), superoxide dismutase-1 (SOD-1), heme oxygenase-1 (HO-1) and NADPH: quinone oxidoreductase 1 (NQO1) in cardiac tissue. Western blot results showed that the expression of GSS was significantly decreased and that the expressions of CAT, SOD-1, and HO-1 were slightly decreased in aged rats. Immunohistochemistry results further confirmed the decreased expression of GSS, SOD-1 and NQO1 in cardiomyocytes in aged rats. Taken together, our data suggest that aging may affect the morphology and function of the heart by oxidative stress and the antioxidative defense mechanism.

Cytotoxic and Photocytotoxic Effects of Cercosporin on Human Tumor Cell Lines

Cercosporin is a naturally occurring perylenequinone. Although other perylenequinones have been extensively studied as photosensitizers in photodynamic therapy of cancer (PDT), cercosporin has been studied in this light only within the remits of phytopathology. Herein, we investigated the photocytotoxicity of cercosporin against two glioblastoma multiforme (T98G and U87) and one breast adenocarcinoma (MCF7) human cell lines. Cercosporin was found to be a potent singlet oxygen producer upon 532 nm excitation, while its cell loading was similar for MCF7 and U87, but approximately threefold higher for T98G cells. The subcellular localization of cercosporin was in all cases in both mitochondria and the endoplasmic reticulum. Light irradiation of cercosporin-incubated cells around 450 nm showed that T98G cells were more susceptible to cercosporin PDT, mainly due to their higher cercosporin uptake. Metabolic studies before and 1 h following cercosporin PDT showed that cercosporin PDT instigated a bioenergetic collapse in both the respiratory and glycolytic activities of all cell lines. In the dark, cercosporin exhibited a synergistic cytotoxicity with copper only in the most respiratory cell lines (MCF7 and T98G). Cercosporin is a potent photosensitizer, but with a short activation wavelength, mostly suitable for superficial PDT treatments, especially when it is necessary to avoid perforations.

Photochemical delivery of bleomycin induces T-cell activation of importance for curative effect and systemic anti-tumor immunity

Photochemical internalization (PCI) is a technology to enhance intracellular drug delivery by light-induced translocation of endocytosed therapeutics into the cytosol. The aim of this study was to explore the efficacy of PCI-based delivery of bleomycin and the impact on systemic anti-tumor immunity. Mouse colon carcinoma cells (CT26.CL25), stably expressing the bacterial β-galactosidase, were inoculated into the legs of athymic or immuno-competent BALB/c mice strains. The mice were injected with the photosensitizer AlPcS_2a and bleomycin (BLM) prior to tumor light exposure from a 670nm diode laser. Photochemical activation of BLM was found to induce synergistic inhibition of tumor growth as compared to the sum of the individual treatments. However, a curative effect was not observed in the athymic mice exposed to 30J/cm² of light while >90% of the thymic mice were cured after exposure to only 15J/cm² light. Cured thymic mice, re-challenged with CT26.CL25 tumor cells on the contralateral leg, rejected 57-100% of the tumor cells inoculated immediately and up to 2months after the photochemical treatment. T-cells from the spleen of PCI-treated mice were found to inhibit the growth of CT26.CL25 cells in naïve thymic mice with a 60% rejection rate. The results show that treatment of CT26.CL25 tumors in thymic mice by PCI of BLM induces a systemic anti-tumor immunity.

Photochemical internalization (PCI) of bleomycin is equally effective in two dissimilar leiomyosarcoma xenografts in athymic mice

BACKGROUND

Photochemical internalization (PCI) is a novel technique for delivery of active macromolecules into cancerous cells, via light activation of a specific photosensitizer and a low dose systemic drug. Numerous pre-clinical studies and one clinical trial have confirmed the treatment potential in carcinomas. Soft tissue sarcomas are rare and generally resistant to radio- and chemotherapy. Due to treatment resistance and surgical morbidity in sarcoma care, we seek to increase knowledge on PCI effects in sarcomas by studying two different, but closely related leiomyosarcomas.

METHODS

MES-SA and SK-LMS-1 tumours were established in the leg muscles of athymic mice. Treatment effects after AlPcS_2a-PCI of bleomycin, PCI with no drug (photodynamic therapy, PDT) and control groups were evaluated by: 1) assessment of tumour growth, 2) uptake of contrast agent during MRI and 3) histopathology.

RESULTS

PCI of bleomycin induced a similar and significant increase in time to reach the end point in both tumour models, while neither responded to AlPcS_2a-PDT. In the MES-SA tumours PCI reduced the growth rate, while in the SK-LMS-1 tumours the growth was blocked for 12days followed by exponential growth close to that of untreated tumours. SK-LMS-1 tumours were more homogenously and better vascularized than MES-SA. After PCI the vascular shutdown was more complete in the SK-LMS-1 tumours than in the MES-SA tumours.

CONCLUSIONS

AlPcS2a-based PCI, but not PDT, induced significant tumour growth delay in the evaluated sarcomas. Cellular responsiveness to bleomycin and tumour vascularity are identified as predictive markers for PCI treatment effects.