VEGF signaling: Role in angiogenesis and beyond.

Angiogenesis is a crucial process for tissue development, repair, and tumor survival. Vascular endothelial growth factor (VEGF) is a key driver secreted by cancer cells, promoting neovascularization. While VEGF's role in angiogenesis is well-documented, its influence on the other aspects in tumor microenvironemt is less discussed. This review elaborates on VEGF's impact on intercellular interactions within the tumor microenvironment, including how VEGF affects pericyte proliferation and migration and mediates interactions between tumor-associated macrophages and cancer cells, resulting in PDL-1-mediated immunosuppression and Nrf2-mediated epithelial-mesenchymal transition. The review discusses VEGF's involvement in intra-organelle crosstalk, tumor metabolism, stemness, and epithelial-mesenchymal transition. It also provides insights into current anti-VEGF therapies and their limitations in cancer treatment. Overall, this review aims to provide a thorough overview of the current state of knowledge concerning VEGF signaling and its impact, not only on angiogenesis but also on various other oncogenic processes.

A role for the cystathionine-ß-synthase /H2S axis in astrocyte dysfunction in the aging brain.

Astrocytic dysfunction is central to age-related neurodegenerative diseases. However, the mechanisms leading to astrocytic dysfunction are not well understood. We identify that among the diverse cellular constituents of the brain, murine and human astrocytes are enriched in the expression of CBS. Depleting CBS in astrocytes causes mitochondrial dysfunction, increases the production of reactive oxygen species (ROS) and decreases cellular bioenergetics that can be partially rescued by exogenous H2S supplementation or by re-expressing CBS. Conversely, the CBS/H2S axis, associated protein persulfidation and proliferation are decreased in astrocytes upon oxidative stress which can be rescued by exogenous H2S supplementation. Here we reveal that in the aging brain, the CBS/H2S axis is downregulated leading to decreased protein persulfidation, together augmenting oxidative stress. Our findings uncover an important protective role of the CBS/H2S axis in astrocytes that may be disrupted in the aged brain.

Fast response and recovery polyaniline montmorillonite reduce graphene oxide polymer nanocomposite material for detection of hydrogen cyanide gas.

In the present work, we have developed a polymer based gas sensor. The polymer nanocomposites are synthesized by the chemical oxidative polymerization of aniline with ammonium persulfate and sulfuric acid. The fabricated sensor is able to achieve a sensing response of 4.56% for PANI/MMT-rGO at 2 ppm of hydrogen cyanide (HCN) gas. The sensitivity of the sensors PANI/MMT and PANI/MMT-rGO are 0.89 ppm-1 and 1.1174 ppm-1 respectively. The increase in the sensitivity of the sensor may be due to an increase in the surface area provided by MMT and rGO which provided more binding sites for the HCN gas. The sensing response of the sensor increases as the concentration of the gas exposed increases but saturates after 10 ppm. The sensor recovers automatically. The sensor is stable and can work for 8 months.

The deubiquitinase USP10 protects pancreatic cancer cells from endoplasmic reticulum stress.

The ubiquitin-specific peptidase 10 (USP10) plays a context-specific, pro or anti-tumorigenic role in different malignancies. However, the role of USP10 in pancreatic cancer remains unclear. Our protein and RNA level analysis from archived specimens and public databases show that USP10 is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and expression correlates with poor overall patient survival. Phenotypically, silencing USP10 decreased viability, clonal growth and invasive properties of pancreatic cancer cells. Mechanistically, silencing USP10 upregulated BiP and induced endoplasmic reticulum (ER) stress that led to an unfolded protein response (UPR) and upregulation of PERK, IRE1α. Decreased cell viability of USP10 silenced cells could be rescued by a chemical chaperone that promotes protein folding. Our studies suggest that USP10 by protecting pancreatic cancer cells from ER stress may support tumor progression.

KRCC1, a modulator of the DNA damage response.

The lysine-rich coiled-coil 1 (KRCC1) protein is overexpressed in multiple malignancies, including ovarian cancer, and overexpression correlates with poor overall survival. Despite a potential role in cancer progression, the biology of KRCC1 remains elusive. Here, we characterize the biology of KRCC1 and define its role in the DNA damage response and in cell cycle progression. We demonstrate that KRCC1 associates with the checkpoint kinase 1 (CHK1) upon DNA damage and regulates the CHK1-mediated checkpoint. KRCC1 facilitates RAD51 recombinase foci formation and augments homologous recombination repair. Furthermore, KRCC1 is required for proper S-phase progression and subsequent mitotic entry. Our findings uncover a novel component of the DNA damage response and a potential link between cell cycle, associated damage response and DNA repair.

Gold Nanoparticles Disrupt the IGFBP2/mTOR/PTEN Axis to Inhibit Ovarian Cancer Growth.

By exploiting the self-therapeutic properties of gold nanoparticles (GNPs) a molecular axis that promotes the growth of high-grade serous ovarian cancer (HGSOC), one of the deadliest gynecologic malignancies with poorly understood underlying molecular mechanisms, has been identified. The biodistribution and toxicity of GNPs administered by intravenous or intraperitoneal injection, both as a single dose or by repeated dosing over two weeks are first assessed; no biochemical or histological toxicity to vital organs is found. Using an orthotopic patient-derived xenograft (PDX) model of HGSOC, the authors then show that GNP treatment robustly inhibits tumor growth. Investigating the molecular mechanisms underlying the GNP efficacy reveals that GNPs downregulate insulin growth factor binding protein 2 (IGFBP2) by disrupting its autoregulation via the IGFBP2/mTOR/PTEN axis. This mechanism is validated by treating a cell line-based human xenograft tumor with GNPs and an mTOR dual-kinase inhibitor (PI-103), either individually or in combination with GNPs; GNP and PI-103 combination therapy inhibit ovarian tumor growth similarly to GNPs alone. This report illustrates how the self-therapeutic properties of GNPs can be exploited as a discovery tool to identify a critical signaling axis responsible for poor prognosis in ovarian cancer and provides an opportunity to interrogate the axis to improve patient outcomes.

Small Non-Coding-RNA in Gynecological Malignancies.

Gynecologic malignancies, which include cancers of the cervix, ovary, uterus, vulva, vagina, and fallopian tube, are among the leading causes of female mortality worldwide, with the most prevalent being endometrial, ovarian, and cervical cancer. Gynecologic malignancies are complex, heterogeneous diseases, and despite extensive research efforts, the molecular mechanisms underlying their development and pathology remain largely unclear. Currently, mechanistic and therapeutic research in cancer is largely focused on protein targets that are encoded by about 1% of the human genome. Our current understanding of 99% of the genome, which includes noncoding RNA, is limited. The discovery of tens of thousands of noncoding RNAs (ncRNAs), possessing either structural or regulatory functions, has fundamentally altered our understanding of genetics, physiology, pathophysiology, and disease treatment as they relate to gynecologic malignancies. In recent years, it has become clear that ncRNAs are relatively stable, and can serve as biomarkers for cancer diagnosis and prognosis, as well as guide therapy choices. Here we discuss the role of small non-coding RNAs, i.e., microRNAs (miRs), P-Element induced wimpy testis interacting (PIWI) RNAs (piRNAs), and tRNA-derived small RNAs in gynecological malignancies, specifically focusing on ovarian, endometrial, and cervical cancer.

Targeting the TGFß pathway in uterine carcinosarcoma.

Uterine carcinosarcoma (UCS) is a relatively infrequent, but extremely aggressive endometrial malignancy. Although surgery and chemotherapy have improved outcomes, overall survival (OS) remains dismal due to the lack of targeted therapy and biphasic (epithelial and mesenchymal) nature that renders the tumor aggressive and difficult to manage. Here we report a role of transforming growth factor-ß (TGFß) in maintaining epithelial to mesenchymal transition (EMT) phenotype and aggressiveness in UCS. Using a 3D-culture system, we evaluated the efficacy of the transforming growth factor-ß receptor-I (TGFßR1) kinase inhibitor Galunisertib (GLT), alone and in combination with standard chemotherapeutic drugs used for the management of UCS. We demonstrate that GLT by inhibiting canonical and non-canonical signaling emanating from transforming growth factor-ß1 (TGFß1) reduces cellular viability, invasion, clonal growth and differentiation. Interestingly, GLT sensitizes UCS cells to chemotherapy both in vitro and in in vivo preclinical tumor model. Hence, targeting TGFß signaling, in combination with standard chemotherapy, may be exploited as an important strategy to manage the clinically challenging UCS.

Cystathione ß-synthase regulates HIF-1α stability through persulfidation of PHD2.

The stringent expression of the hypoxia inducible factor-1α (HIF-1α) is critical to a variety of pathophysiological conditions. We reveal that, in normoxia, enzymatic action of cystathionine ß-synthase (CBS) produces H2S, which persulfidates prolyl hydroxylase 2 (PHD2) at residues Cys21 and Cys33 (zinc finger motif), augmenting prolyl hydroxylase activity. Depleting endogenous H2S either by hypoxia or by inhibiting CBS via chemical or genetic means reduces persulfidation of PHD2 and inhibits activity, preventing hydroxylation of HIF-1α, resulting in stabilization. Our in vitro findings are further supported by the depletion of CBS in the zebrafish model that exhibits axis defects and abnormal intersegmental vessels. Exogenous H2S supplementation rescues both in vitro and in vivo phenotypes. We have identified the persulfidated residues and defined their functional significance in regulating the activity of PHD2 via point mutations. Thus, the CBS/H2S/PHD2 axis may provide therapeutic opportunities for pathologies associated with HIF-1α dysregulation in chronic diseases.

MicroRNA-195 controls MICU1 expression and tumor growth in ovarian cancer.

MICU1 is a mitochondrial inner membrane protein that inhibits mitochondrial calcium entry; elevated MICU1 expression is characteristic of many cancers, including ovarian cancer. MICU1 induces both glycolysis and chemoresistance and is associated with poor clinical outcomes. However, there are currently no available interventions to normalize aberrant MICU1 expression. Here, we demonstrate that microRNA-195-5p (miR-195) directly targets the 3' UTR of the MICU1 mRNA and represses MICU1 expression. Additionally, miR-195 is under-expressed in ovarian cancer cell lines, and restoring miR-195 expression reestablishes native MICU1 levels and the associated phenotypes. Stable expression of miR-195 in a human xenograft model of ovarian cancer significantly reduces tumor growth, increases tumor doubling times, and enhances overall survival. In conclusion, miR-195 controls MICU1 levels in ovarian cancer and could be exploited to normalize aberrant MICU1 expression, thus reversing both glycolysis and chemoresistance and consequently improving patient outcomes.

Ubiquitin-binding associated protein 2 regulates KRAS activation and macropinocytosis in pancreatic cancer.

Macropinocytosis supports the metabolic requirement of RAS-transformed pancreatic ductal adenocarcinoma cells (PDACs). However, regulators of RAS-transformation (activation) that lead to macropinocytosis have not been identified. Herein, we report that UBAP2 (ubiquitin-binding associated protein 2), regulates the activation of KRAS and macropinocytosis in pancreatic cancer. We demonstrate that UBAP2 is highly expressed in both pancreatic cancer cell lines and tumor tissues of PDAC patients. The expression of UBAP2 is associated with poor overall survival in several cancers, including PDAC. Silencing UBAP2 decreases the levels of activated KRAS, and inhibits macropinocytosis, and tumor growth in vivo. Using a UBAP2-deletion construct, we demonstrate that the UBA-domain of UBAP2 is critical for the regulation of macropinocytosis and maintaining the levels of activated KRAS. In addition, UBAP2 regulates RAS downstream signaling and helps maintain RAS in the GTP-bound form. However, the exact mechanism by which UBAP2 regulates KRAS activation is unknown and needs further investigation. Thus, UBAP2 may be exploited as a potential therapeutic target to inhibit macropinocytosis and tumor growth in activated KRAS-driven cancers.

Cystathionine beta synthase regulates mitochondrial dynamics and function in endothelial cells.

Mutations in the human cystathionine beta synthase (CBS) gene are known to cause endothelial dysfunction responsible for cardiovascular and neurovascular diseases. CBS is the predominant hydrogen sulfide (H2 S)-producing enzyme in endothelial cells (ECs). Recently, H2 S was shown to attenuate ROS and improve mitochondrial function. Mitochondria are metabolic organelles that actively transform their ultrastructure to mediate their function. Therefore, we questioned whether perturbation of CBS/H2 S activity could drive mitochondrial dysfunction via mitochondrial dynamics in ECs. Here we demonstrate that silencing CBS induces mitochondria fragmentation, attenuates efficient oxidative phosphorylation, and decreases EC function. Mechanistically, CBS silencing significantly elevates ROS production, thereby leading to reduced mitofusin 2 (MFN2) expression, decouple endoplasmic reticulum-mitochondria contacts, increased mitochondria fission, enhanced receptor-mediated mitophagy, and increased EC death. These defects were significantly rescued by the treatment of H2 S donors. Taken together our data highlights a novel signaling axis that mechanistically links CBS with mitochondrial function and ER-mitochondrial tethering and could be considered as a new therapeutic approach for the intervention of EC dysfunction-related pathologies.

KRCC1: A potential therapeutic target in ovarian cancer.

Using a systems biology approach to prioritize potential points of intervention in ovarian cancer, we identified the lysine rich coiled-coil 1 (KRCC1), as a potential target. High-grade serous ovarian cancer patient tumors and cells express significantly higher levels of KRCC1 which correlates with poor overall survival and chemoresistance. We demonstrate that KRCC1 is predominantly present in the chromatin-bound nuclear fraction, interacts with HDAC1, HDAC2, and with the serine-threonine phosphatase PP1CC. Silencing KRCC1 inhibits cellular plasticity, invasive properties, and potentiates apoptosis resulting in reduced tumor growth. These phenotypes are associated with increased acetylation of histones and with increased phosphorylation of H2AX and CHK1, suggesting the modulation of transcription and DNA damage that may be mediated by the action of HDAC and PP1CC, respectively. Hence, we address an urgent need to develop new targets in cancer.

Multifunctional APJ Pathway Promotes Ovarian Cancer Progression and Metastasis.

High mortality rates in ovarian cancer are due to late-stage diagnosis when extensive metastases are present, coupled with the eventual development of resistance to standard chemotherapy. There is, thus, an urgent need to identify targetable pathways to curtail this deadly disease. In this study, we show that the apelin receptor, APJ, is a viable target that promotes tumor progression of high-grade serous ovarian cancer (HGSOC). APJ is specifically overexpressed in tumor tissue, and is elevated in metastatic tissues compared with primary tumors. Importantly, increased APJ expression significantly correlates with decreased median overall survival (OS) by 14.7 months in patients with HGSOC. Using various ovarian cancer model systems, we demonstrate that APJ expression in cancer cells is both necessary and sufficient to increase prometastatic phenotypes in vitro, including proliferation, cell adhesion to various molecules of the extracellular matrix (ECM), anoikis resistance, migration, and invasion; and these phenotypes are efficiently inhibited by the APJ inhibitor, ML221. Overexpression of APJ also increases metastasis of ovarian cancer cells in vivo. Mechanistically, the prometastatic STAT3 pathway is activated downstream of APJ, and in addition to the ERK and AKT pathways, contributes to its aggressive phenotypes. Our findings suggest that the APJ pathway is a novel and viable target, with potential to curb ovarian cancer progression and metastasis. IMPLICATIONS: The APJ pathway is a viable target in HGSOC.

Inhibition of BMI1, a Therapeutic Approach in Endometrial Cancer.

With rising incidence rates, endometrial cancer is one of the most common gynecologic malignancies in the United States. Although surgery provides significant survival benefit to early-stage patients, those with advanced or recurrent metastatic disease have a dismal prognosis. Limited treatment options include chemotherapy and radiotherapy. Hence, there is a compelling need for developing molecularly targeted therapy. Here, we show that the polycomb ring finger protein BMI1, also known as a stem cell factor, is significantly overexpressed in endometrial cancer cell lines, endometrial cancer patient tissues as well as in nonendometrioid histologies and associated with poor overall survival. PTC-028, a second-generation inhibitor of BMI1 function, decreases invasion of endometrial cancer cells and potentiates caspase-dependent apoptosis, while normal cells with minimal expression of BMI1 remain unaffected. In an aggressive uterine carcinosarcoma xenograft model, single-agent PTC-028 significantly delayed tumor growth and increased tumor doubling time compared with the standard carboplatin/paclitaxel therapy. Therefore, anti-BMI1 strategies may represent a promising targeted approach in patients with advanced or recurrent endometrial cancer, a population where treatment options are limited. Mol Cancer Ther; 17(10); 2136-43. ©2018 AACR.

Evaluating the Mechanism and Therapeutic Potential of PTC-028, a Novel Inhibitor of BMI-1 Function in Ovarian Cancer.

BMI-1, also known as a stem cell factor, is frequently upregulated in several malignancies. Elevated expression of BMI-1 correlates with poor prognosis and is therefore considered a viable therapeutic target in a number of malignancies including ovarian cancer. Realizing the immense pathologic significance of BMI-1, small-molecule inhibitors against BMI-1 are recently being developed. In this study, we functionally characterize PTC-028, an orally bioavailable compound that decreases BMI-1 levels by posttranslational modification. We report that PTC-028 treatment selectively inhibits cancer cells in clonal growth and viability assays, whereas normal cells remain unaffected. Mechanistically, hyperphosphorylation-mediated depletion of cellular BMI-1 by PTC-028 coupled with a concurrent temporal decrease in ATP and a compromised mitochondrial redox balance potentiates caspase-dependent apoptosis. In vivo, orally administered PTC-028, as a single agent, exhibits significant antitumor activity comparable with the standard cisplatin/paclitaxel therapy in an orthotopic mouse model of ovarian cancer. Thus, PTC-028 has the potential to be used as an effective therapeutic agent in patients with epithelial ovarian cancer, where treatment options are limited. Mol Cancer Ther; 17(1); 39-49. ©2017 AACR.

MICU1 drives glycolysis and chemoresistance in ovarian cancer.

Cancer cells actively promote aerobic glycolysis to sustain their metabolic requirements through mechanisms not always clear. Here, we demonstrate that the gatekeeper of mitochondrial Ca2+ uptake, Mitochondrial Calcium Uptake 1 (MICU1/CBARA1) drives aerobic glycolysis in ovarian cancer. We show that MICU1 is overexpressed in a panel of ovarian cancer cell lines and that MICU1 overexpression correlates with poor overall survival (OS). Silencing MICU1 in vitro increases oxygen consumption, decreases lactate production, inhibits clonal growth, migration and invasion of ovarian cancer cells, whereas silencing in vivo inhibits tumour growth, increases cisplatin efficacy and OS. Mechanistically, silencing MICU1 activates pyruvate dehydrogenase (PDH) by stimulating the PDPhosphatase-phosphoPDH-PDH axis. Forced-expression of MICU1 in normal cells phenocopies the metabolic aberrations of malignant cells. Consistent with the in vitro and in vivo findings we observe a significant correlation between MICU1 and pPDH (inactive form of PDH) expression with poor prognosis. Thus, MICU1 could serve as an important therapeutic target to normalize metabolic aberrations responsible for poor prognosis in ovarian cancer.

BMI1, a new target of CK2α.

BACKGROUND: The polycomb group protein, BMI1 plays important roles in chromatin modification, stem cell function, DNA damage repair and mitochondrial bioenergetics. Such diverse cellular functions of BMI1 could be, in part, due to post-translational modifications, especially phosphorylation. To date, AKT has been reported as a kinase that by site specific phosphorylation of BMI1 modulates its oncogenic functions. METHODS: Immunoprecipitation in conjunction with kinase assay and mass spectrometry was used to determine association with and site specific phosphorylation of BMI1 by CK2α. Functional implications of the BMI1/CK2α axis was examined in cancer cells utilizing siRNA and exogenous gene expression followed by biochemical and phenotypic studies. Correlations between expression of CK2α and BMI1 were determined from cell lines and formalin fixed paraffin embedded tissues representing the normal fallopian tube epithelium and high grade serous ovarian cancer samples. RESULTS: Here we report that CK2α, a nuclear serine threonine kinase, phosphorylates BMI1 at Serine 110 as determined by in-vitro/ex-vivo kinase assay and mass spectrometry. In ovarian cancer cell lines, expression of CK2α correlated with the phospho-species, as well as basal BMI1 levels. Preventing phosphorylation of BMI1 at Serine 110 significantly decreased half-life and stability of the protein. Additionally, re-expression of the phosphorylatable but not non-phosphorylatable BMI1 rescued clonal growth in endogenous BMI1 silenced cancer cells leading us to speculate that CK2α-mediated phosphorylation stabilizes BMI1 and promotes its oncogenic function. Clinically, compared to normal fallopian tube epithelial tissues, the expression of both BMI1 and CK2α were significantly higher in tumor tissues obtained from high-grade serous ovarian cancer patients. Among tumor samples, the expression of BMI1 and CK2α positively correlated (Spearman coefficient = 0.62, P = 0.0021) with each other. CONCLUSION: Taken together, our findings establish an important regulatory role of CK2α on BMI1 phosphorylation and stability and implicate the CK2α/BMI1 axis in ovarian cancer.

Gold Nanoparticle Reprograms Pancreatic Tumor Microenvironment and Inhibits Tumor Growth.

Altered tumor microenvironment (TME) arising from a bidirectional crosstalk between the pancreatic cancer cells (PCCs) and the pancreatic stellate cells (PSCs) is implicated in the dismal prognosis in pancreatic ductal adenocarcinoma (PDAC), yet effective strategies to disrupt the crosstalk is lacking. Here, we demonstrate that gold nanoparticles (AuNPs) inhibit proliferation and migration of both PCCs and PSCs by disrupting the bidirectional communication via alteration of the cell secretome. Analyzing the key proteins identified from a functional network of AuNP-altered secretome in PCCs and PSCs, we demonstrate that AuNPs impair secretions of major hub node proteins in both cell types and transform activated PSCs toward a lipid-rich quiescent phenotype. By reducing activation of PSCs, AuNPs inhibit matrix deposition, enhance angiogenesis, and inhibit tumor growth in an orthotopic co-implantation model in vivo. Auto- and heteroregulations of secretory growth factors/cytokines are disrupted by AuNPs resulting in reprogramming of the TME. By utilizing a kinase dead mutant of IRE1-α, we demonstrate that AuNPs alter the cellular secretome through the ER-stress-regulated IRE1-dependent decay pathway (RIDD) and identify endostatin and matrix metalloproteinase 9 as putative RIDD targets. Thus, AuNPs could potentially be utilized as a tool to effectively interrogate bidirectional communications in the tumor microenvironment, reprogram it, and inhibit tumor growth by its therapeutic function.