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Immunohistochemical detection of cytoplasmic LC3 puncta in human cancer specimens.

ABSTRACT: Autophagy is an evolutionarily conserved catabolic process that involves the entrapment of cytoplasmic components within characteristic vesicles for their delivery to and degradation within lysosomes. Alterations in autophagic signaling are found in several human diseases including cancer. Here, we describe a validated immunohistochemical protocol for the detection of LC3 puncta in human formalin-fixed, paraffin-embedded cancer specimens that can also be applied to mouse tissues. In response to systemic chemotherapy, autophagy-competent mouse tumors exhibited LC3 puncta, which did not appear in mouse cancers that had been rendered autophagy-deficient by the knockdown of Atg5 or Atg7. As compared with normal tissues, LC3 staining was moderately to highly elevated in the large majority of human cancers studied, albeit tumors of the same histological type tended to be highly heterogeneous in the number and intensity of LC3 puncta per cell. Moreover, tumor-infiltrating immune cells often were highly positive for LC3. Altogether, this protocol for LC3 staining appears suitable for the specific detection of LC3 puncta in human specimens, including tissue microarrays. We surmise that this technique can be employed for retrospective or prospective studies involving large series of human tumor samples.

SUBMITTER: Ladoire S

PROVIDER: S-EPMC3973657 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature

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Immunohistochemical detection of cytoplasmic LC3 puncta in human cancer specimens.

Ladoire Sylvain S Chaba Kariman K Martins Isabelle I Sukkurwala Abdul Qader AQ Adjemian Sandy S Michaud Mickaël M Poirier-Colame Vichnou V Andreiuolo Felipe F Galluzzi Lorenzo L White Eileen E Rosenfeldt Mathias M Ryan Kevin M KM Zitvogel Laurence L Kroemer Guido G

Autophagy 20120531 8

Autophagy is an evolutionarily conserved catabolic process that involves the entrapment of cytoplasmic components within characteristic vesicles for their delivery to and degradation within lysosomes. Alterations in autophagic signaling are found in several human diseases including cancer. Here, we describe a validated immunohistochemical protocol for the detection of LC3 puncta in human formalin-fixed, paraffin-embedded cancer specimens that can also be applied to mouse tissues. In response to ...[more]

PMID: 22647537

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Project description:Therapy resistance can be attributed to acquisition of anti-apoptotic mechanisms by the cancer cells. Therefore, developing approaches that trigger non-apoptotic cell death in cancer cells to compensate for apoptosis resistance will help to treat cancer effectively. Triple-negative breast cancers (TNBC) are among the most aggressive and therapy resistant to breast tumors. Here we report that manumycin A (Man A), an inhibitor of farnesyl protein transferase, reduces cancer cell viability through induction of non-apoptotic, non-autophagic cytoplasmic vacuolation death in TNBC cells. Man A persistently induced cytoplasmic vacuolation and cell death through the expression of microtubule-associated protein 1 light chain 3 (LC3) and p62 proteins along with endoplasmic reticulum (ER) stress markers, Bip and CHOP, and accumulation of ubiquitinated proteins. As inhibitors of apoptosis and autophagy failed to block cytoplasmic vacuolation and its associated protein expression or cell death, it appears that these processes are not involved in the death induced by Man A. Ability of thiol antioxidant, NAC in blocking Man A-induced vacuolation, death and its related protein expression suggests that sulfhydryl homeostasis may be the target of Man A. Surprisingly, normal human mammary epithelial cells failed to undergo cytoplasmic vacuolation and cell death, and grew normally in presence of Man A. In conjunction with its in vitro effects, Man A also reduced tumor burden in vivo in xenograft models that showed extensive cytoplasmic vacuoles and condensed nuclei with remarkable increase in the vacuolation-associated protein expression together with increase of p21, p27, PTEN and decrease of pAkt. Interestingly, Man A-mediated upregulation of p21, p27 and PTEN and downregulation of pAkt and tumor growth suppression were also mimicked by LC3 knockdown in MDA-MB-231 cells. Overall, these results suggest novel therapeutic actions by Man A through the induction of non-apoptotic and non-autophagic cytoplasmic vacuolation death by probably affecting ER stress, LC3 and p62 pathways in TNBC but not in normal mammary epithelial cells.

Project description:ObjectiveThe aim of this study is to explore the consistency of P53 immunohistochemical expression between preoperative biopsy and final pathology in endometrial cancer (EC), and to predict the prognosis of patients based on the 4-tier P53 expression and classic clinicopathological parameters.MethodsThe medical data of patients with stage I-III EC who received preoperative biopsy and initial surgical treatment in two medical centers was retrospectively collected. The consistency of P53 immunohistochemistry expression between preoperative biopsy and final pathology was compared using Cohen's kappa coefficient and Sankey diagram, then 4-tier P53 expression was defined (P53wt/P53wt, P53abn/P53wt, P53wt/P53abn, and P53abn/P53abn). Univariate and multivariate Cox regression analysis was used to determine the correlation between 4-tier P53 expression and the prognosis of patients. On this basis, the nomogram models were established to predict the prognosis of patients by combining 4-layer P53 expression and classic clinicopathological parameters, then risk stratification was performed on patients.ResultsA total of 1186 patients were ultimately included in this study through inclusion and exclusion criteria. Overall, the consistency of P53 expression between preoperative biopsy and final pathology was 83.8%, with a kappa coefficient of 0.624. ROC curve suggested that the AUC of 4-tier P53 expression to predict the prognosis of patients was better than AUC of P53 expression in preoperative biopsy or final pathology alone. Univariate and multivariate Cox regression analysis suggested that 4-tier P53 expression was an independent influencing factor for recurrence and death. On this basis, the nomogram models based on 4-tier P53 expression and classical clinicopathological factors were successfully established. ROC curve suggested that the AUC (AUC for recurrence and death was 0.856 and 0.838, respectively) of the models was superior to the single 4-tier P53 expression or the single classical clinicopathological parameters, which could provide a better risk stratification for patients.ConclusionThe expression of P53 immunohistochemistry had relatively good consistency between preoperative biopsy and final pathology of EC. Due to the discrepancy of P53 immunohistochemistry between preoperative biopsy and final pathology, the prognosis of patients can be better evaluated based on the 4-layer P53 expression and classic clinical pathological parameters.

Project description:We previously showed that nuclear localization of the actin-binding protein, filamin A (FlnA), corresponded to hormone-dependence in prostate cancer. Intact FlnA (280 kDa, cytoplasmic) cleaved to a 90 kDa fragment which translocated to the nucleus in hormone-naïve cells, whereas in hormone-refractory cells, FlnA was phosphorylated, preventing its cleavage and nuclear translocation. We have examined whether FlnA localization determines a propensity to metastasis in advanced androgen-independent prostate cancer.We examined, by immunohistochemistry, FlnA localization in paraffin-embedded human prostate tissue representing different stages of progression. Results were correlated with in vitro studies in a cell model of prostate cancer.Nuclear FlnA was significantly higher in benign prostate (0.6612 +/- 0.5888), prostatic intraepithelial neoplasia (PIN; 0.6024 +/- 0.4620), and clinically localized cancers (0.69134 +/- 0.5686) compared with metastatic prostate cancers (0.3719 +/- 0.4992, P = 0.0007). Cytoplasmic FlnA increased from benign prostate (0.0833 +/- 0.2677), PIN (0.1409 +/- 0.2293), localized cancers (0.3008 +/- 0.3762, P = 0.0150), to metastases (0.7632 +/- 0.4414, P < 0.00001). Logistic regression of metastatic versus nonmetastatic tissue yielded the area under the receiver operating curve as 0.67 for nuclear-FlnA, 0.79 for cytoplasmic-FlnA, and 0.82 for both, indicating that metastasis correlates with cytoplasmic to nuclear translocation. In vitro studies showed that cytoplasmic localization of FlnA induced cell invasion whereas nuclear translocation of the protein inhibited it. FlnA dephosphorylation with the protein kinase A inhibitor H-89 facilitated FlnA nuclear translocation, resulting in decreased invasiveness and AR transcriptional activity, and induced sensitivity to androgen withdrawal in hormone-refractory cells.The data presented in this study indicate that in prostate cancer, metastasis correlates with cytoplasmic localization of FlnA and may be prevented by cleavage and subsequent nuclear translocation of this protein.

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Immunohistochemical detection of cytoplasmic LC3 puncta in human cancer specimens.

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Immunohistochemical detection of cytoplasmic LC3 puncta in human cancer specimens.

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