Localization of heat shock protein 110 in canine mammary gland tumors

HSP110 expression in canine mammary gland tumor and its correlation with histopathological classification and grade

Heat shock proteins (HSPs) play critical roles as molecular chaperones, thereby promoting cellular homeostasis. HSPs are overexpressed in many types of human tumors and their serum concentration is elevated in cancer patients. Recent studies have suggested that HSPs may promote tumorigenesis via interactions with tumor-related proteins. There are only a few studies that address the expression of HSPs in canine tumors. In our previous study, we identified elevated levels of HSP110 expression in canine mammary gland tumors (cMGTs). In this study, we examined both serum concentrations and tissue expression of HSP110 in dogs with cMGT. We found that serum HSP110 concentrations were not significantly different in a comparison between dogs with cMGT (3.44 ± 1.27 μg/mL) and healthy controls (3.23 ± 1.18 μg/mL). By contrast, significant differences in levels of HSP110 expression were identified in comparisons between simple carcinoma and benign mixed tumor (p = 0.001), simple carcinoma and non-neoplastic lesions (p < 0.001), complex carcinoma and benign mixed tumor (p = 0.015), complex carcinoma and non-neoplastic lesions (p < 0.001), simple adenoma and benign mixed tumor (p = 0.041), and simple adenoma and non-neoplastic lesions (p = 0.007). Similarly, significantly different levels of HSP110 expression were identified when comparing grade Ⅲ with non-neoplastic lesion (p = 0.026), grade Ⅱ with benign tumor (p = 0.015), grade Ⅱ with non-neoplastic lesion (p < 0.001), and grade Ⅰ with non-neoplastic lesion (p < 0.001). Taken together, our results indicate that expression of HSP110 correlates with the malignancy in this cohort of dogs diagnosed with cMGT. These findings also suggest that HSP110 is associated with tumorigenesis and the relative malignancy of cMGT.

First detection of heat shock protein 60 and 70 in the serum of early pregnant bitches

Heat shock proteins (HSPs) belong to a group of cellular stress proteins. Heat shock protein 10 immunoregulates and promotes growth during early gestation in humans, while HSP70 is considered to regulate autophagy and apoptosis during pregnancy and parturition. Both HSPs are detectable in the serum and placentas of early pregnant women and considered to contribute to the establishment of pregnancy. Within this pilot study we aimed (1) to assess whether HSPs 10, 60 and 70 are measurable in the serum of healthy early pregnant and non-pregnant bitches, and (2) to explore whether measurable differences between groups indicate pregnancy. Blood was collected from 31 bitches on days 7, 14 and 21 after mating. At 21 days post mating, all bitches were examined for pregnancy by ultrasonography; 23 were pregnant, and the eight non-pregnant bitches served as controls. Pregnant bitches had normal parturitions and gave birth to healthy puppies. The serum concentrations of HSPs 10, 60 and 70 were measured by electrophoresis and western blot. Serum HSP10 was not detectable. Average serum HSP70 concentration was significantly (d7, P = 0.030; d14, P = 0.023; d21, P = 0.030) lower in pregnant animals at all days investigated, while serum HSP60 was significantly lower at day 21 of gestation (P = 0.024) when compared to the controls. HSP 60 and HSP70 concentrations correlated positively (d7, r = +0.386, P = 0.021; d14, r = 0.450, P = 0.008; d21, r = +0.472, P = 0.006). We conclude that in pregnant bitches, serum concentrations of HSP60 and HSP70 are significantly decreased between days 7 and 21 of gestation, in comparison to non-pregnant bitches in early dioestrus, raising the question about intrauterine functions during the peri-implantation period.