Apoptosis: its role in pituitary development and neoplastic pituitary tissue

The hallmarks of cancer… in pituitary tumors?

Over 20 years ago, Hanahan and Weinberg published a seminal review that addressed the biological processes that underly malignant transformation. This classical review, along with two revisions published in 2011 and 2022, has remain a classic of the oncology literature. Since many of the addressed biological processes may apply to non-malignant tumorigenesis, we evaluated to what extent these hallmarks pertain to the development of pituitary adenomas.Some of the biological processes analyzed in this review include genome instability generated by somatic USP8 and GNAS mutations in Cushing's diseases and acromegaly respectively; non-mutational epigenetic reprograming through changes in methylation; induction of angiogenesis through alterations of VEGF gene expression; promotion of proliferative signals mediated by EGFR; evasion of growth suppression by disrupting cyclin dependent kinase inhibitors; avoidance of immune destruction; and the promotion of inflammation mediated by alteration of gene expression of immune check points. We also elaborate further on the existence of oncogene induced senescence in pituitary tumors. We conclude that a better understanding of these processes can help us dilucidated why pituitary tumors are so resistant to malignant transformation and can potentially contribute to the development of novel anticancer treatments.

Tanshinone IIA: New Perspective on the Anti-Tumor Mechanism of A Traditional Natural Medicine

The search for natural and efficacious antineoplastic drugs, with minimal toxicity and side effects, is an important part of antitumor drug research and development. Tanshinone IIA is the most evaluated lipophilic active component of Salvia miltiorrhiza. Tanshinone IIA is a path-breaking traditional drug applied in cardiovascular treatment. It has also been found that tanshinone IIA plays an important role in the digestive, respiratory and circulatory systems, as well as in other tumor diseases. Tanshinone IIA significantly inhibits the proliferation of several types of tumors, blocks the cell cycle, induces apoptosis and autophagic death, in addition to inhibiting cell migration and invasion. Among these, the regulation of tumor-cell apoptosis signaling pathways is the key breakthrough point in several modes of antitumor therapy. The PI3K/AKT/MTOR signaling pathway and the JNK pathway are the key pathways for tanshinone IIA to induce tumor cell apoptosis. In addition to glycolysis, reactive oxygen species and signal transduction all play an active role with the participation of tanshinone IIA. Endogenous apoptosis is considered the main mechanism of tumor apoptosis induced by tanshinone IIA. Multiple pathways and targets play a role in the process of endogenous apoptosis. Tanshinone IIA can protect chemotherapy drugs, which is mainly reflected in the protection of the side effects of chemotherapy drugs, such as neurotoxicity and inhibition of the hematopoietic system. Tanshinone IIA also has a certain regulatory effect on tumor angiogenesis, which is mainly manifested in the control of hypoxia. Our findings indicated that tanshinone IIA is an effective treatment agent in the cardiovascular field and plays a significant role in antitumor therapeutics. This paper reviews the pharmacological potential and inhibitory effect of tanshinone IIA on cancer. It is greatly anticipated that tanshinone IIA will be employed as an adjuvant in the treatment of various cancers.

Evaluation of the expression of necroptosis pathway mediators and its association with tumor characteristics in functional and non-functional pituitary adenomas

BACKGROUND

Pituitary adenomas impose a burden of morbidity on patients and characterizing the molecular mechanisms underlying its pathogenesis received remarkable attention. Despite the appealing role of necroptosis as an alternative cell death pathway in cancer pathogenesis, its relevance to pituitary adenoma pathogenesis has yet to be determined that is perused in the current study.

METHODS

The total number of 109 specimens including pituitary adenomas and cadaveric healthy pituitary tissues were enrolled in the current study. Tumor and healthy pituitary tissues were subjected to RNA extraction and gene analysis using Real-Time PCR. The expression levels of necroptosis markers (RIP1K, RIP3K and, MLKL) and their association with the patient's demographic features were evaluated, also the protein level of MLKL was assessed using immunohistochemistry in tissues.

RESULTS

Based on our data, the remarkable reduction in RIP3K and MLKL expression were detected in nonfunctional and GH-secreting pituitary tumors compared to pituitary normal tissues. Invasive tumors revealed lower expression of RIP3K and MLKL compared to non-invasive tumors, also the attenuated level of MLKL was associated with the tumor size in invasive NFPA. The simultaneous down-regulation of MLKL protein in pituitary adenoma tissues was observed which was in line with its gene expression. While, RIP1K over-expressed significantly in both types of pituitary tumors which showed no significant correlation with patient's age, gender and tumor size in GHPPA and NFPA group. Notably, MLKL and RIP3K gene expression was significantly correlated in the GHPPA group.

CONCLUSIONS

According to our data, the reduced expression of necroptosis mediators (RIP3K, MLKL) in pituitary adenoma reinforces the hypothesis that the necroptosis pathway can be effective in regulating the proliferation and growth of pituitary tumor cells and tumor recurrence.

Architects of Pituitary Tumour Growth

The pituitary is a master gland responsible for the modulation of critical endocrine functions. Pituitary neuroendocrine tumours (PitNETs) display a considerable prevalence of 1/1106, frequently observed as benign solid tumours. PitNETs still represent a cause of important morbidity, due to hormonal systemic deregulation, with surgical, radiological or chronic treatment required for illness management. The apparent scarceness, uncommon behaviour and molecular features of PitNETs have resulted in a relatively slow progress in depicting their pathogenesis. An appropriate interpretation of different phenotypes or cellular outcomes during tumour growth is desirable, since histopathological characterization still remains the main option for prognosis elucidation. Improved knowledge obtained in recent decades about pituitary tumorigenesis has revealed that this process involves several cellular routes in addition to proliferation and death, with its modulation depending on many signalling pathways rather than being the result of abnormalities of a unique proliferation pathway, as sometimes presented. PitNETs can display intrinsic heterogeneity and cell subpopulations with diverse biological, genetic and epigenetic particularities, including tumorigenic potential. Hence, to obtain a better understanding of PitNET growth new approaches are required and the systematization of the available data, with the role of cell death programs, autophagy, stem cells, cellular senescence, mitochondrial function, metabolic reprogramming still being emerging fields in pituitary research. We envisage that through the combination of molecular, genetic and epigenetic data, together with the improved morphological, biochemical, physiological and metabolically knowledge on pituitary neoplastic potential accumulated in recent decades, tumour classification schemes will become more accurate regarding tumour origin, behaviour and plausible clinical results.

Inhibitory Effect of Hydroxysafflor Yellow B on the Proliferation of Human Breast Cancer MCF-7 Cells

BACKGROUND

A recent patent has been issued for hydroxysafflor yellow A (HSYA) as a drug to prevent blood circulation disorders. Hydroxysafflor yellow B (HSYB), an isomer of HSYA with antioxidative effects, has been isolated from the florets of Carthamus tinctorius. The effects of HSYB on the proliferation of cancer cells and its mechanism of action have not been investigated.

OBJECTIVE

The aims of this study were to investigate the anti-cancer effects and the molecular mechanism of HSYB for breast cancer MCF-7 cells.

METHODS

MTT assays and colony formation assays were used to assess the survival and proliferation of MCF-7 cells, respectively. Hoechst 33258 and flow cytometry were used to measure cell apoptosis and flow cytometry to determine effects on the cell cycle. Western blots were used to measure protein levels.

RESULTS

Treatment with HSYB reduced survival and proliferation of human breast cancer MCF-7 cells in a dose-dependent manner. Furthermore, HSYB arrested the MCF-7 cell cycle at the S phase and downregulated cyclin D1, cyclin E, and CDK2. Compared with a control group, HSYB suppressed the protein levels of p-PI3K, PI3K, AKT, and p-AKT in MCF-7 cells. In addition, HSYB decreased the levels of Bcl- 2, increased the levels of Bax, cleaved caspase-3 and caspase-9, and subsequently induced MCF-7 cell apoptosis.

CONCLUSION

These data demonstrate that HSYB arrests the MCF-7 cell cycle at the S phase and induces cell apoptosis. Patent US20170246228 indicates that HSYB can be potentially used for the prevention and treatment of human breast cancer.

Mitochondrial Dysfunction Pathway Networks and Mitochondrial Dynamics in the Pathogenesis of Pituitary Adenomas

Mitochondrion is a multi-functional organelle, which is associated with various signaling pathway networks, including energy metabolism, oxidative stress, cell apoptosis, cell cycles, autophagy, and immunity process. Mitochondrial proteins have been discovered to modulate these signaling pathway networks, and multiple biological behaviors to adapt to various internal environments or signaling events of human pathogenesis. Accordingly, mitochondrial dysfunction that alters the bioenergetic and biosynthetic state might contribute to multiple diseases, including cell transformation and tumor. Multiomics studies have revealed that mitochondrial dysfunction, oxidative stress, and cell cycle dysregulation signaling pathways operate in human pituitary adenomas, which suggest mitochondria play critical roles in pituitary adenomas. Some drugs targeting mitochondria are found as a therapeutic strategy for pituitary adenomas, including melatonin, melatonin inhibitors, temozolomide, pyrimethamine, 18 beta-glycyrrhetinic acid, gossypol acetate, Yougui pill, T-2 toxin, grifolic acid, cyclosporine A, dopamine agonists, and paeoniflorin. This article reviews the latest experimental evidence and potential biological roles of mitochondrial dysfunction and mitochondrial dynamics in pituitary adenoma progression, potential molecular mechanisms between mitochondria and pituitary adenoma progression, and current status and perspectives of mitochondria-based biomarkers and targeted drugs for effective management of pituitary adenomas.

miR-1269 promotes cell survival and proliferation by targeting tp53 and caspase-9 in lung cancer

Background and aim

Lung cancer is the leading cause of cancer death worldwide. In this study, we aim to elucidate the role of miR-1269 in the pathogenesis of lung cancer.

Methods and results

From the results of analyses using The Cancer Genome Atlas (TCGA) database, we noted the expression of miR-1269 was increased in lung cancer tissue. miR-1269 expression was detected in both the normal adjacent lung tissue and in the tumorous lung tissue of lung cancer patients, and miR-1269 was more highly expressed in the tumors. High expression of miR-1269 correlated with patients’ tumor stage and lymph node metastasis. A Cell Counting Kit-8 (CCK8) analysis and a cloning formation assay showed that overexpression of miR-1269 significantly promoted the growth of A549 cells, and that a lower expression of miR-1269 significantly increased cell apoptosis. We used the TargetScan 6.2 Database to predict the potential targets of miR-1269, and a luciferase activity assay was used to determine the direct interaction between miR-1269, tumor protein p53 (TP53), and caspase-9. Results from Western blots and real-time PCR showed that overexpression of miR-1269 significantly inhibited TP53 and caspase-9 expression. In addition, caspase-3 activity was found to decrease in a miR-1269 mimic group. The results showed that gene silencing of TP53 and caspase-9 significantly inhibited A549 cell growth and promoted cell apoptosis. The results also showed that the inhibition of miR-1269 and caspase-9 expression inhibited cell apoptosis. Immunohistochemistry (IHC) results demonstrated that TP53 and caspase-9 were expressed in low levels in tumor tissues, and that an inverse correlation exists between miR-1269 expression levels and TP53 or caspase-9 expression levels.

Conclusion

These results demonstrate that miR-1269 promotes cell survival and proliferation by targeting TP53 and caspase-9 in lung cancer.

Opposite effects of dihydrotestosterone and estradiol on apoptosis in the anterior pituitary gland from male rats

Hormones locally synthesized in the anterior pituitary gland are involved in regulation of pituitary cell renewal. In the pituitary, testosterone (T) may exert its actions per se or by conversion to dihydrotestosterone (DHT) or 17β-estradiol (E2) by 5α-reductase and aromatase activity, which are expressed in this gland. Previous reports from our laboratory showed that estrogens modulate apoptosis of lactotropes and somatotropes from female rats. Now, we examined the in vitro and in vivo effects of gonadal steroids on apoptosis of anterior pituitary cells from adult male rats. T in vitro did not modify apoptosis in anterior pituitary cells from gonadectomized (GNX) male rats. DHT, a non-aromatizable androgen, exerted direct antiapoptotic action on total anterior pituitary cells and folliculo-stellate cells, but not on lactotropes, somatotropes, or gonadotropes. On the contrary, E2 exerted a rapid apoptotic effect on total cells as well as on lactotropes and somatotropes. Incubation of anterior pituitary cells with T in presence of Finasteride, an inhibitor of 5α-reductase, increased the percentage of TUNEL-positive cells. In vivo administration of DHT to GNX rats reduced apoptosis in the anterior pituitary whereas E2 exerted proapoptotic action and reduced cells in G2/M-phase of the cell cycle. In summary, our results indicate that DHT and E2 have opposite effects on apoptosis in the anterior pituitary gland suggesting that local metabolization of T to these steroids could be involved in pituitary cell turnover in males. Changes in expression and/or activity of 5α-reductase and aromatase may play a role in the development of anterior pituitary tumors.

Decreased expression of APAF-1 and increased expression of cathepsin B in invasive pituitary adenoma

PURPOSE

Apoptotic protease-activating factor-1 (APAF-1) and cathepsin B are important functional proteins in apoptosis; the former is involved in the intrinsic (mitochondrial) pathway, while the latter is associated with both intrinsic and extrinsic pathways. Changes in the expression of apoptosome-related proteins could be useful indicators of tumor development since a priori defects in the mitochondrial pathway might facilitate the inception and progression of human neoplasms. Our aim was to evaluate the profiles of APAF-1 and cathepsin B in relation with other molecules involved in apoptosis/proliferation and to correlate them with the aggressive behavior of invasive pituitary adenomas.

MATERIALS AND METHODS

APAF-1 and cathepsin B were assessed in tissue samples from 30 patients with pituitary adenomas, of which 16 were functional adenomas and 22 were invasive adenomas.

RESULTS

A positive relationship between high proliferation and invasiveness was observed in invasive pituitary adenomas when compared to their noninvasive counterparts (Ki-67 labeling index - 4.72% versus 1.75%). Decreased expression of APAF-1 was recorded in most of the invasive adenomas with a high proliferation index, while the cathepsin B level was elevated in this group. We have noticed a negative correlation between the low level of APAF-1 and invasiveness (63.63%; P<0.01); at the same time, a positive correlation between cathepsin B expression and invasiveness (59.09%; P<0.01) was found. In all, 81.25% out of the total APAF-1-positive samples were cathepsin B negative (P<0.01); 76.92% out of the total cathepsin B-positive samples were APAF-1-negative (P<0.01). These results were reinforced by an apoptosis protein array examination, which showed inhibition of the extrinsic apoptotic pathway in an invasive pituitary adenoma.

CONCLUSION

A bidirectional-inverted relationship between APAF-1 and cathepsin B expressions was noticed. One might hypothesize that shifting the balance between mediators of cell death could result in changes in tumor behavior.

The PI3K/AKT/mTOR pathway in the pathophysiology and treatment of pituitary adenomas

Pituitary adenomas are common intracranial neoplasms. Patients with these tumors exhibit a wide range of clinically challenging problems, stemming either from results of sellar mass effect in pituitary macroadenoma or the diverse effects of aberrant hormone production by adenoma cells. While some patients are cured/controlled by surgical resection and/or medical therapy, a proportion of patients exhibit tumors that are refractory to current modalities. New therapeutic approaches are needed for these patients. Activation of the AKT/phophotidylinositide-3-kinase pathway, including mTOR activation, is common in human neoplasia, and a number of therapeutic approaches are being employed to neutralize activation of this pathway in human cancer. This review examines the role of this pathway in pituitary tumors with respect to tumor biology and its potential role as a therapeutic target.

Rathke's cleft cysts in twins with type 2C von Hippel-Lindau disease

Von Hippel-Lindau disease (VHLD) is characterized by a spectrum of benign and malignant tumors in the CNS and visceral organs. Rathke's cleft cysts are benign, nonneoplastic sellar lesions that are often asymptomatic. The authors report the case of twin sisters with VHLD Type 2C with radiographically similar sellar lesions. One twin required surgery for progressive visual loss. Pathological examination of resected tissue demonstrated Rathke's cleft cyst.

Pro-apoptosis gene PUMA and cancer

The dysfunction of cell apoptosis signaling is involved in carcinogenesis. P53 up-regulated modulator of apoptosis (PUMA), a pro-apoptosis gene that has been found for a decade, encodes a protein that is one of Bcl-2 members and can induce apoptosis via the mitochondrial pathway. It is considered that mutation of the PUMA gene is not involved in carcinogenesis, because mutation of the PUMA gene has not been found in many types of tumors until now. The expression of PUMA protein is regulated transcriptionally via ER stress, p53, JNK, FOXO3a and E2F1 signaling or post-translationally by phosphorylation. Several studies have showed that the down-regulation of PUMA protein in cancer tissue is associated with carcinogenesis, lymph node metastasis and tumor prognosis, and that up-regulation of PUMA induces the inhibition of cancer cell proliferation. Increasing new findings on the precise role of PUMA in the regulation of cancer development provide new insights into the potential use of PUMA as a target for the prevention and treatment of cancer.