An asymmetrically dimethylarginated nuclear 90 kDa protein (p90aDMA) induced by interleukin (IL)-2, IL-4 or IL-6 in the tumor microenvironment is selectively degraded by autophagy

Selective degradation of PL2L60 by metabolic stresses‑induced autophagy suppresses multi‑cancer growth

It has been reported that PL2L60 proteins, a product of PIWIL2 gene which might be activated by an intragenic promoter, could mediate a common pathway specifically for tumorigenesis. In the present study, it was further identified by using western blot assay that the PL2L60 proteins could be degraded in cancer cells through a mechanism of selective autophagy in response to oxidative stress. The PL2L60 was downregulated in various types of cancer cells under the hypoxic condition independently of HIF‑1α, resulting in apoptosis of cancer cells. Inhibition of autophagy by small interfering RNA targeting of either Beclin‑1 (BECN1) or Atg5 resulted in restoration of PL2L60 expression in hypoxic cancer cell. The hypoxic degradation of PL2L60 was also blocked by the attenuation of the autophagosome membrane protein Atg8/microtubule‑associated protein 1 light chain 3 (LC3) or autophagy cargo protein p62 expression. Surprisingly, Immunofluorescence analysis demonstrated that LC3 could be directly bound to PL2L60 and was required for the transport of PL2L60 from the nucleus to the cytoplasm for lysosomal flux under basal or activated autophagy in cancer cells. Moreover, flow cytometric analysis displayed that knocking down of PL2L60 mRNA but not PIWIL2 mRNA effectively inhibited cancer cell proliferation and promoted apoptosis of cancer cells. The similar results were obtained from in vivo tumorigenic experiment, in which PL2L60 downregulation in necroptosis areas was confirmed by immunohistochemistry. These results suggested that various cancer could be suppressed by promoting autophagy. The present study revealed a key role of autophagic degradation of PL2L60 in hypoxia‑induced cancer cell death, which could be used as a novel therapeutic target of cancer.

[Influence of the HLDF differentiation factor on the production of cytokines by bio-tissues of breast tissue in its non-malignant diseases and in invasive carcinoma of a non-specific type]

We studied the effect of the HLDF differentiation factor on production of cytokines by biopsy samples of nonmalignant breast diseases (ND) and invasive breast carcinoma of no special type (IBC-NST), in the absence and presence of lymphogenic metastasis: IBC-NST patients werw subdivided into groups on the prognostic protocol of the 8th edition of the AJCC committee. Group IA consisted of patients with T1-T2 tumor sizes, and predominantly with positive expression of estrogen and progesterone receptors (ER+/PR+/HER2-); it also included one patient with the HER2+ (ER-/PR-/HER2+) molecular subtype. The IB group was mainly composed of patients with T2 tumor size, with the presence of lymphogenic metastasis (in 8 out of 10) patients and with positive expression of estrogen and progesterone receptors (ER+/PR+/HER2-) and it also included three patients with the HER2+ (ER-/PR-/HER2+) molecular subtype. Group IIA consisted of patients with T1-T2 tumor sizes, mainly with no metastases in the lymph nodes (in 11 out of 12 patients) and with a triple negative molecular subtype. Group IIB included patients with T2 tumor size, the presence of nodal metastasis and the expression of markers of ER-/PR-/HER2 - and ER-/PR-/HER2+. Group IIIA consisted of patients with tumor size T1-T3, with the presence of nodal metastasis and the expression of markers of ER-/PR+/HER2+ and ER-/PR-/HER2+. Group IIIC consisted of patients with T3 tumor size, lymphogenic metastasis, and expression of ER-/PR-/HER2-markers (triple negative molecular subtype). Due to a limited number of patients in the groups IIB, IIIA and IIIC, as well as due to more severe clinical and pathological stages, according to the prognostic Protocol of the 8th edition of the AJCC Committee, they were pooled into group III. Concentrations of IL-2, IL-4, IL-6, IL-8, IL-10, IL-17, IL-18, IL-1β, IL-1Ra, TNF-α, IFN-γ, G-CSF, GM-CSF, VEGF and MCP-1 were assayed in supernatants of biopsy specimens of breast tissue. Results have shown that with IBC-NST, a statistically significantly higher level of spontaneous production (SP) by biopsy specimens of IL-17, IL-18, IFN-γ and VEGF, and a lower level of SP IL-6 as compared with ND. Patients of all clinical and pathological groups showed a high VEGF spontaneous production as compared with ND, while statistically significant differences from patients with ND were not found in IL-17 spontaneous production in group IB patients, and IL-18 spontaneous production were absent in group IA. Only in patients with IA and IB, the IL-6 spontaneous production was lower as compared to ND, and the IL-8 spontaneous production was lower in the IA group. IFN-γ spontaneous production was higher in patients with IBC-NST group IIA as compared with ND. Under the influence of the HLDF differentiation factor, it was found that the parameters of IBC-NST patients were statistically significantly higher in the production of IL-1Ra, IL-17, IL-18 and VEGF, and statistically significantly lower in the production of IL-6 as compared to ND. HLDF had a higher impact on the content of IL-18 in IBC-NST patients than in ND. After HDLF sublimation IL-6 values were lower in patients of groups IA and IB, and HLDF-induced IL-17 production was higher only in patients of group IA. Statistically significant differences in the index of influence of HLDF (IVHLDF), representing ratio of the cytokine concentration in the supernatants of a biopsy specimen stimulated by HLDF to spontaneous cytokine production, were found between ND and IBC-NST in the case of on IFN-γ production, and also in the case of IL-4 production (between patients in the absence and presence of lymphogenic metastasis). IVHLDF for production of IL-6, IL-8 and TNF-α was lower in group IIA patients compared to group IA, and IVHLDF for production of GM-CSF and MCP-1 was lower in group IIA as compared to group III, in addition IVHLDF for MCP-1 products was lower in group IIA as compared to ND. The HLDF effect on the cytokine production by the tumor and its microenvironment was different in ND patients and IBC-NST patients. HDLF suppressed IFN-γ production in the pooled group of IBC-NST patients; HLDF mainly had a suppressive effect on the production of IL-6, IL-8, TNF-α, GM-CSF and MCP-1 in IBC-NST patients of group IIA.