Prognostic impact of Dynamin related protein 1 (Drp1) in epithelial ovarian cancer

Drp1 splice variants regulate ovarian cancer mitochondrial dynamics and tumor progression

Aberrant mitochondrial fission/fusion dynamics are frequently associated with pathologies, including cancer. We show that alternative splice variants of the fission protein Drp1 (DNM1L) contribute to the complexity of mitochondrial fission/fusion regulation in tumor cells. High tumor expression of the Drp1 alternative splice variant lacking exon 16 relative to other transcripts is associated with poor outcome in ovarian cancer patients. Lack of exon 16 results in Drp1 localization to microtubules and decreased association with mitochondrial fission sites, culminating in fused mitochondrial networks, enhanced respiration, changes in metabolism, and enhanced pro-tumorigenic phenotypes in vitro and in vivo. These effects are inhibited by siRNAs designed to specifically target the endogenously expressed transcript lacking exon 16. Moreover, lack of exon 16 abrogates mitochondrial fission in response to pro-apoptotic stimuli and leads to decreased sensitivity to chemotherapeutics. These data emphasize the pathophysiological importance of Drp1 alternative splicing, highlight the divergent functions and consequences of changing the relative expression of Drp1 splice variants in tumor cells, and strongly warrant consideration of alternative splicing in future studies focused on Drp1.

Teriflunomide/leflunomide synergize with chemotherapeutics by decreasing mitochondrial fragmentation via DRP1 in SCLC

Although up to 80% small cell lung cancer (SCLC) patients' response is good for first-line chemotherapy regimen, most patients develop recurrence of the disease within weeks to months. Here, we report cytostatic effect of leflunomide (Leflu) and teriflunomide (Teri) on SCLC cell proliferation through inhibition of DRP1 phosphorylation at Ser616 and decreased mitochondrial fragmentation. When administered together, Teri and carboplatin (Carbo) act synergistically to significantly inhibit cell proliferation and DRP1 phosphorylation, reduce abundance of intermediates in pyrimidine de novo pathway, and increase apoptosis and DNA damage. Combination of Leflu&Carbo has anti-tumorigenic effect in vivo. Additionally, lurbinectedin (Lur) and Teri potently and synergistically inhibited spheroid growth and depleted uridine and DRP1 phosphorylation in mouse tumors. Our results suggest combinations of Carbo and Lur with Teri or Leflu are efficacious and underscore how the relationship between DRP1/DHODH and mitochondrial plasticity serves as a potential therapeutic target to validate these treatment strategies in SCLC clinical trials.

A novel MTORC2-AKT-ROS axis triggers mitofission and mitophagy-associated execution of colorectal cancer cells upon drug-induced activation of mutant KRAS

RAS is one of the most commonly mutated oncogenes associated with multiple cancer hallmarks. Notably, RAS activation induces intracellular reactive oxygen species (ROS) generation, which we previously demonstrated as a trigger for autophagy-associated execution of mutant KRAS-expressing cancer cells. Here we report that drug (merodantoin; C1)-induced activation of mutant KRAS promotes phospho-AKT S473-dependent ROS-mediated S616 phosphorylation and mitochondrial localization of DNM1L/DRP1 (dynamin 1 like) and cleavage of the fusion-associated protein OPA1 (OPA1 mitochondrial dynamin like GTPase). Interestingly, accumulation of the outer mitochondrial membrane protein VDAC1 (voltage dependent anion channel 1) is observed in mutant KRAS-expressing cells upon exposure to C1. Conversely, silencing VDAC1 abolishes C1-induced mitophagy, and gene knockdown of either KRAS, AKT or DNM1L rescues ROS-dependent VDAC1 accumulation and stability, thus suggesting an axis of mutant active KRAS-phospho-AKT S473-ROS-DNM1L-VDAC1 in mitochondrial morphology change and cancer cell execution. Importantly, we identified MTOR (mechanistic target of rapamycin kinsase) complex 2 (MTORC2) as the upstream mediator of AKT phosphorylation at S473 in our model. Pharmacological or genetic inhibition of MTORC2 abrogated C1-induced phosphorylation of AKT S473, ROS generation and mitophagy induction, as well as rescued tumor colony forming ability and migratory capacity. Finally, increase in thermal stability of KRAS, AKT and DNM1L were observed upon exposure to C1 only in mutant KRAS-expressing cells. Taken together, our work has unraveled a novel mechanism of selective targeting of mutant KRAS-expressing cancers via MTORC2-mediated AKT activation and ROS-dependent mitofission, which could have potential therapeutic implications given the relative lack of direct RAS-targeting strategies in cancer.Abbreviations: ACTB/ß-actin: actin beta; AKT: AKT serine/threonine kinase; C1/merodantoin: 1,3-dibutyl-2-thiooxo-imidazoldine-4,5-dione; CAT: catalase; CETSA: cellular thermal shift assay; CHX: cycloheximide; DKO: double knockout; DNM1L/DRP1: dynamin 1 like; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; H2O2: hydrogen peroxide; HSPA1A/HSP70-1: heat shock protein family A (Hsp70) member 1A; HSP90AA1/HSP90: heat shock protein 90 alpha family class A member 1; KRAS: KRAS proto-oncogene, GTPase; MAP1LC3B/LC3B, microtubule associated protein 1 light chain 3 beta; LC3B-I: unlipidated form of LC3B; LC3B-II: phosphatidylethanolamine-conjugated form of LC3B; MAPKAP1/SIN1: MAPK associated protein 1; MAPK1/ERK2: mitogen-activated protein kinase 1; MAPK3/ERK1: mitogen-activated protein kinase 3; MFI: mean fluorescence intensity; MiNA: Mitochondrial Network Analysis; MTOR: mechanistic target of rapamycin kinase; MTORC1: mechanistic target of rapamycin kinase complex 1; MTORC2: mechanistic target of rapamycin kinase complex 2; O2.-: superoxide; OMA1: OMA1 zinc metallopeptidase; OPA1: OPA1 mitochondrial dynamin like GTPase; RICTOR: RPTOR independent companion of MTOR complex 2; ROS: reactive oxygen species; RPTOR/raptor: regulatory associated protein of MTOR complex 1; SOD1: superoxide dismutase 1; SOD2: superoxide dismutase 2; SQSTM1/p62: sequestosome 1; VDAC1: voltage dependent anion channel 1; VDAC2: voltage dependent anion channel 2.

Pathogenesis of Warthin's Tumor: Neoplastic or Non-Neoplastic?

Warthin's tumor is the second most frequent neoplasm next to pleomorphic adenoma in the salivary gland, mostly in the parotid gland. The epithelial cells constituting a tumor are characterized by the presence of mitochondria that undergo structural and functional changes, resulting in the development of oncocytes. In addition to containing epithelial cells, Warthin's tumors contain abundant lymphocytes with lymph follicles (germinal centers) that are surrounded by epithelial cells. The pathogenesis of Warthin's tumor is not fully understood, and several hypotheses have been proposed. The risk factors for the development of Warthin's tumor, which predominantly occurs in males, include aging, smoking, and radiation exposure. Recently, it has been reported that chronic inflammation and aging cells promote the growth of Warthin's tumor. Several reports regarding the origin of the tumor have suggested that (1) Warthin's tumor is an IgG4-related disease, (2) epithelial cells that compose Warthin's tumor accumulate mitochondria, and (3) Warthin's tumor is a metaplastic lesion in the lymph nodes. It is possible that the pathogenesis of Warthin's tumor includes mitochondrial metabolic abnormalities, accumulation of aged cells, chronic inflammation, and senescence-associated secretory phenotype (SASP). In this short review, we propose that DNA damage, metabolic dysfunction of mitochondria, senescent cells, SASP, human papillomavirus, and IgG4 may be involved in the development of Warthin's tumor.

Alternative splice variants of the mitochondrial fission protein DNM1L/Drp1 regulate mitochondrial dynamics and tumor progression in ovarian cancer

Aberrant mitochondrial fission/fusion dynamics have been reported in cancer cells. While post translational modifications are known regulators of the mitochondrial fission/fusion machinery, we show that alternative splice variants of the fission protein Drp1 (DNM1L) have specific and unique roles in cancer, adding to the complexity of mitochondrial fission/fusion regulation in tumor cells. Ovarian cancer specimens express an alternative splice transcript variant of Drp1 lacking exon 16 of the variable domain, and high expression of this splice variant relative to other transcripts is associated with poor patient outcome. Unlike the full-length variant, expression of Drp1 lacking exon 16 leads to decreased association of Drp1 to mitochondrial fission sites, more fused mitochondrial networks, enhanced respiration, and TCA cycle metabolites, and is associated with a more metastatic phenotype in vitro and in vivo. These pro-tumorigenic effects can also be inhibited by specific siRNA-mediated inhibition of the endogenously expressed transcript lacking exon 16. Moreover, lack of exon 16 abrogates mitochondrial fission in response to pro-apoptotic stimuli and leads to decreased sensitivity to chemotherapeutics. These data emphasize the significance of the pathophysiological consequences of Drp1 alternative splicing and divergent functions of Drp1 splice variants, and strongly warrant consideration of Drp1 splicing in future studies.

Ets1 facilitates EMT/invasion through Drp1-mediated mitochondrial fragmentation in ovarian cancer

Ovarian cancer has sustained as a major cause of cancer-related female mortality owing to its aggressive nature and a dearth of early detection markers. Ets1 oncoprotein, a transcription factor belonging to the Ets family, is a well-established promoter of epithelial to mesenchymal transition (EMT) and a prospective malignancy marker in ovarian cancer. Our study establishes Ets1 as a regulator of mitochondrial fission-fusion dynamics through Drp1 augmentation via direct binding at DNM1L (DRP1) promoter. Ets1 overexpression-mediated Drp1 increment resulted in mitochondrial load reduction and compromised OXPHOS Complex 5 (ATP synthase) expression, facilitating a greater reliance on glycolysis over OXPHOS. Furthermore, our work demonstrates that inhibition of mitochondrial fission through molecular or pharmacological inhibition of Drp1 successfully mitigates Ets1-associated EMT in both in vitro and in vivo syngeneic mice model. Collectively, our data highlight the role of Drp1-mediated mitochondrial fragmentation in driving Ets1-mediated bioenergetic alterations and EMT/invasion in ovarian cancer.

Mitochondrial Dynamics as Potential Modulators of Hormonal Therapy Effectiveness in Males

Worldwide the incidence of andrological diseases is rising every year and, together with it, also the interest in them is increasing due to their strict association with disorders of the reproductive system, including impairment of male fertility, alterations of male hormones production, and/or sexual function. Prevention and early diagnosis of andrological dysfunctions have long been neglected, with the consequent increase in the incidence and prevalence of diseases otherwise easy to prevent and treat if diagnosed early. In this review, we report the latest evidence of the effect of andrological alterations on fertility potential in both young and adult patients, with a focus on the link between gonadotropins' mechanism of action and mitochondria. Indeed, mitochondria are highly dynamic cellular organelles that undergo rapid morphological adaptations, conditioning a multitude of aspects, including their size, shape, number, transport, cellular distribution, and, consequently, their function. Since the first step of steroidogenesis takes place in these organelles, we consider that mitochondria dynamics might have a possible role in a plethora of signaling cascades, including testosterone production. In addition, we also hypothesize a central role of mitochondria fission boost on the decreased response to the commonly administrated hormonal therapy used to treat urological disease in pediatric and adolescent patients as well as infertile adults.

Prognostic significance of dynamin-related protein 1 expression in advanced lung adenocarcinoma

BACKGROUND

Dynamin-related protein 1 (DRP1) is a key regulator of mitochondrial fission and is activated by phosphorylation at serine 616. We previously demonstrated that DRP1 activation is regulated by epidermal growth factor receptor (EGFR) signaling and multiple kinases in lung adenocarcinoma, and is significantly associated with an increased risk of postoperative recurrence in early stage lung adenocarcinoma. However, it is unclear whether DRP1 activation is associated with worse prognosis in patients with advanced lung adenocarcinoma. This study is aimed to examine whether P(S616)-DRP1 expression is significantly related to the survival of patients with advanced lung adenocarcinoma.

MATERIALS AND METHODS

Biopsy samples were obtained from patients with stage IV lung adenocarcinoma. The activation status of DRP1 in cancer cells was quantified based on the immunohistochemical stain of phosphorylated DRP1 at serine 616 [P(S616)-DRP1]. Results of EGFR, ALK, ROS1, and KRAS mutations were retrieved from the medical records. The staining intensity and the histological scores (H-scores) of P(S616)-DRP1 were analyzed for association with progression-free survival (PFS) under first-line tyrosine-kinase inhibitors (TKIs) and with overall survival (OS).

RESULTS

Overall, 123 patients with stage IV lung adenocarcinoma constituted the study population, and 90 (73.2%) patients received TKIs as the first-line treatments. The median P(S616)-DRP1H-score was used to dichotomize the study population into the high (n = 61) and low (n = 62) DRP1 activation groups. DRP1 was significantly less phosphorylated in lung adenocarcinoma with EGFR, ALK, ROS1, and KRAS mutations. Importantly, in patients who received first-line TKIs, DRP1 phosphorylation was not significantly correlated with PFS and OS. Multivariate Cox proportional hazard models showed that high DRP1 activation in cancer cells was not significantly associated with worse OS in the study population (adjusted hazard ratio: 1.402, 95% confidence interval: 0.865-2.271, p = 0.170). Similar results were obtained in the analysis based on the intensities of P(S616)-DRP1 in cancer cells.

CONCLUSIONS

Our data demonstrate that DRP1 phosphorylation is not related to the prognosis of patients with advanced lung adenocarcinoma.

Mitochondrial Dysfunction Pathway Alterations Offer Potential Biomarkers and Therapeutic Targets for Ovarian Cancer

The mitochondrion is a very versatile organelle that participates in some important cancer-associated biological processes, including energy metabolism, oxidative stress, mitochondrial DNA (mtDNA) mutation, cell apoptosis, mitochondria-nuclear communication, dynamics, autophagy, calcium overload, immunity, and drug resistance in ovarian cancer. Multiomics studies have found that mitochondrial dysfunction, oxidative stress, and apoptosis signaling pathways act in human ovarian cancer, which demonstrates that mitochondria play critical roles in ovarian cancer. Many molecular targeted drugs have been developed against mitochondrial dysfunction pathways in ovarian cancer, including olive leaf extract, nilotinib, salinomycin, Sambucus nigra agglutinin, tigecycline, and eupatilin. This review article focuses on the underlying biological roles of mitochondrial dysfunction in ovarian cancer progression based on omics data, potential molecular relationship between mitochondrial dysfunction and oxidative stress, and future perspectives of promising biomarkers and therapeutic targets based on the mitochondrial dysfunction pathway for ovarian cancer.

DRP1 contributes to head and neck cancer progression and induces glycolysis through modulated FOXM1/MMP12 axis

Abnormal DRP1 expression has been identified in a variety of human cancers. However, the prognostic potential and mechanistic role of DRP1 in head and neck cancer (HNC) are currently poorly understood. Here, we demonstrated a significant upregulation of DRP1 in HNC tissues, and that DRP1 expression correlates with poor survival of HNC patients. Diminished DRP1 expression suppressed tumor growth and metastasis in both in vitro and in vivo models. DRP1 expression was positively correlated with FOXM1 and MMP12 expression in HNC patient samples, suggesting pathological relevance in the context of HNC development. Moreover, DRP1 depletion affected aerobic glycolysis through the downregulation of glycolytic genes, and overexpression of MMP12 in DRP1‐depleted cells could help restore glucose consumption and lactate production. Using ChIP‐qPCR, we showed that DRP1 modulates FOXM1 expression, which can enhance MMP12 transcription by binding to its promoter. We also showed that miR‐575 could target 3’UTR of DRP1 mRNA and suppress DRP1 expression. Collectively, our study provides mechanistic insights into the role of DRP1 in HNC and highlights the potential of targeting the miR‐575/DRP1/FOXM1/MMP12 axis as a novel therapy for the prevention of HNC progression.

Identification of key genes associated with papillary thyroid microcarcinoma characteristics by integrating transcriptome sequencing and weighted gene co-expression network analysis

OBJECTIVE

Papillary thyroid microcarcinoma (PTMC) is the most prevalent histological type of thyroid carcinoma. Despite the overall favorable prognosis of PTMC, some cases exhibit aggressive phenotypes. The identification of robust biomarkers may improve early PTMC diagnosis. In this study, we integrated high-throughput transcriptome sequencing, bioinformatic analyses and experimental validation to identify key genes associated with the malignant characteristics of PTMC.

METHODS

Total RNA was extracted from 24 PTMC samples and 7 non-malignant thyroid tissue samples, followed by RNA sequencing. The differentially expressed genes (DEGs) were identified and used to construct co-expression networks by weighted gene co-expression network analysis (WGCNA). Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed, and protein-protein interaction networks were constructed. Key modules and hub genes showing a strong correlation with the malignant characteristics of PTMC were identified and validated.

RESULTS

The green-yellow and turquoise modules generated by WGCNA were strongly associated with the malignant characteristics of PTMC. Functional enrichment analysis revealed that genes in the green-yellow module participated in cell motility and metabolism, whereas those in the turquoise module participated in several oncogenic biological processes. Nine real hub genes (FHL1, NDRG2, NEXN, SYNM, COL1A1, FN1, LAMC2, POSTN, and TGFBI) were identified and validated at the transcriptional and translational levels. Our preliminary results indicated their diagnostic potentials in PTMC.

CONCLUSIONS

In this study, we identified key co-expression modules and nine malignancy-related genes with potential diagnostic value in PTMC.

Highly Antiproliferative Latonduine and Indolo[2,3-c]quinoline Derivatives: Complex Formation with Copper(II) Markedly Changes the Kinase Inhibitory Profile

A series of latonduine and indoloquinoline derivatives HL¹–HL⁸ and their copper(II) complexes (1–8) were synthesized and comprehensively characterized. The structures of five compounds (HL⁶, [CuCl(L¹)(DMF)]·DMF, [CuCl(L²)(CH₃OH)], [CuCl(L³)]·0.5H₂O, and [CuCl₂(H₂L⁵)]Cl·2DMF) were elucidated by single crystal X-ray diffraction. The copper(II) complexes revealed low micro- to sub-micromolar IC₅₀ values with promising selectivity toward human colon adenocarcinoma multidrug-resistant Colo320 cancer cells as compared to the doxorubicin-sensitive Colo205 cell line. The lead compounds HL⁴ and 4 as well as HL⁸ and 8 induced apoptosis efficiently in Colo320 cells. In addition, the copper(II) complexes had higher affinity to DNA than their metal-free ligands. HL⁸ showed selective inhibition for the PIM-1 enzyme, while 8 revealed strong inhibition of five other enzymes, i.e., SGK-1, PKA, CaMK-1, GSK3β, and MSK1, from a panel of 50 kinases. Furthermore, molecular modeling of the ligands and complexes showed a good fit to the binding pockets of these targets.

Role of Mitochondria in Interplay between NGF/TRKA, miR-145 and Possible Therapeutic Strategies for Epithelial Ovarian Cancer

Ovarian cancer is the most lethal gynecological neoplasm, and epithelial ovarian cancer (EOC) accounts for 90% of ovarian malignancies. The 5-year survival is less than 45%, and, unlike other types of cancer, the proportion of women who die from this disease has not improved in recent decades. Nerve growth factor (NGF) and tropomyosin kinase A (TRKA), its high-affinity receptor, play a crucial role in pathogenesis through cell proliferation, angiogenesis, invasion, and migration. NGF/TRKA increase their expression during the progression of EOC by upregulation of oncogenic proteins as vascular endothelial growth factor (VEGF) and c-Myc. Otherwise, the expression of most oncoproteins is regulated by microRNAs (miRs). Our laboratory group reported that the tumoral effect of NGF/TRKA depends on the regulation of miR-145 levels in EOC. Currently, mitochondria have been proposed as new therapeutic targets to activate the apoptotic pathway in the cancer cell. The mitochondria are involved in a myriad of functions as energy production, redox control, homeostasis of Ca⁺², and cell death. We demonstrated that NGF stimulation produces an augment in the Bcl-2/BAX ratio, which supports the anti-apoptotic effects of NGF in EOC cells. The review aimed to discuss the role of mitochondria in the interplay between NGF/TRKA and miR-145 and possible therapeutic strategies that may decrease mortality due to EOC.

Insulin signaling, androgen receptor and PSMA immunohistochemical analysis by semi-automated tissue microarray in prostate cancer with diabetes (DIAMOND study)

In the last years, many studies have highlighted the hypothesis that diabetes and hyperglycemia could be relevant for prostate cancer (PC) development and progression. We aimed to identify the prognostic value of tissue expression of androgen receptor (AR), Prostate-Specific Membrane Antigen (PSMA), Ki-67, insulin receptors (IR)  α and β, insulin growth factor-1 (IGF-1) receptor, in patients with PC and to evaluate their association with diabetes. We retrospectively collected data from 360 patients who underwent radical prostatectomy for PC or surgery for benign prostatic hyperplasia (BPH), between 2010 and 2020. We constructed tissue microarray for immunohistochemistry (IHC) analysis. In the final cohort (76 BPH and 284 PC), 57 (15.8%) patients had diabetes, 17 (22.37%) in BPH and 40 (14.08%) in PC (P = 0.08). IR-α was more expressed in patients with PC compared to the BPH Group (95.96% vs 4.04%; P <0.01). We found that AR was associated with increased risk of International Society of Urological Pathology (ISUP) score ≥4 (OR: 2.2; P <0.05), higher association with Ki-67 (OR: 2.2; P <0.05) and IR-α (OR: 5.7; P <0.05); IGF-1 receptor was associated with PSMA (OR: 2.8; P <0.05), Ki-67 (OR: 3.5; P <0.05) and IR-β (OR: 5.1; P <0.05). Finally, IGF-1 receptor was predictive of ISUP ≥ 4 (OR: 16.5; P =0.017) in patients with PC and diabetes. In the present study we highlighted how prostate cancer patients have a different protein expression in the tissue. This expression, and in particular that relating to IGF-1R, is associated with greater tumor aggressiveness in those patients with diabetes. We suppose that these results are attributable to an alteration of the insulin signal which therefore determines a greater mitogenic activity that can influence tumor progression.

GNG4 Promotes Tumor Progression in Colorectal Cancer

Colorectal cancer is a common digestive system tumor, which lacks effective therapeutic targets and biomarkers to accurately determine the prognosis. Sequencing data, immunohistochemistry, and Kaplan–Meier analysis were used to explore GNG4 clinical significance in colorectal cancer. And, through in vitro experiments, the effects of GNG4 on cell behaviors were investigated. The results showed that the mRNA and protein expression levels of GNG4 in patients with colorectal cancer were significantly higher than in normal people. The patients with high GNG4 expression had a worse prognosis than patients with low GNG4 expression. The in vitro experiments presented that after downregulating the expression of GNG4, proliferation, migration, and invasion of SW-620 colon cancer cells were all significantly reduced, apoptosis was significantly increased, and the cell cycle was blocked in the S phase. In summary, GNG4 may be of importance in the therapy of the colorectal cancer; therefore, targeting GNG4 may have certain clinical value in the treatment of colorectal cancer.

Mitochondrial dynamics regulators: implications for therapeutic intervention in cancer

Regardless of the recent advances in therapeutic developments, cancer is still among the primary causes of death globally, indicating the need for alternative therapeutic strategies. Mitochondria, a dynamic organelle, continuously undergo the fusion and fission processes to meet cell requirements. The balanced fission and fusion processes, referred to as mitochondrial dynamics, coordinate mitochondrial shape, size, number, energy metabolism, cell cycle, mitophagy, and apoptosis. An imbalance between these opposing events alters mitochondWangrial dynamics, affects the overall mitochondrial shape, and deregulates mitochondrial function. Emerging evidence indicates that alteration of mitochondrial dynamics contributes to various aspects of tumorigenesis and cancer progression. Therefore, targeting the mitochondrial dynamics regulator could be a potential therapeutic approach for cancer treatment. This review will address the role of imbalanced mitochondrial dynamics in mitochondrial dysfunction during cancer progression. We will outline the clinical significance of mitochondrial dynamics regulators in various cancer types with recent updates in cancer stemness and chemoresistance and its therapeutic potential and clinical utility as a predictive biomarker.

Fine-tuned repression of Drp1-driven mitochondrial fission primes a 'stem/progenitor-like state' to support neoplastic transformation

Gene knockout of the master regulator of mitochondrial fission, Drp1, prevents neoplastic transformation. Also, mitochondrial fission and its opposing process of mitochondrial fusion are emerging as crucial regulators of stemness. Intriguingly, stem/progenitor cells maintaining repressed mitochondrial fission are primed for self-renewal and proliferation. Using our newly derived carcinogen transformed human cell model, we demonstrate that fine-tuned Drp1 repression primes a slow cycling 'stem/progenitor-like state', which is characterized by small networks of fused mitochondria and a gene-expression profile with elevated functional stem/progenitor markers (Krt15, Sox2 etc) and their regulators (Cyclin E). Fine tuning Drp1 protein by reducing its activating phosphorylation sustains the neoplastic stem/progenitor cell markers. Whereas, fine-tuned reduction of Drp1 protein maintains the characteristic mitochondrial shape and gene-expression of the primed 'stem/progenitor-like state' to accelerate neoplastic transformation, and more complete reduction of Drp1 protein prevents it. Therefore, our data highlights a 'goldilocks' level of Drp1 repression supporting stem/progenitor state dependent neoplastic transformation.

Prognostic and clinical significance of Solute Carrier Family 7 Member 1 in ovarian cancer

Background

Members of the solute carrier (SLC)7 family are known to play important roles in tumorigenesis and development. However, the prognostic significance of the SLC7 family in ovarian cancer (OC) remains unknown.

Methods

Expression patterns of SLC7 family members in OC were analyzed using gene expression profiling interactive analysis (GEPIA). The Kaplan-Meier plotter was applied to evaluate associations of the SLC7 gene family with prognosis of OC. SLC7A1 expression was additionally analyzed via immunohistochemical staining. χ², Kaplan-Meier and Cox regression analysis were used to evaluate the relationship between SLC7A1 expression and clinicopathological features, platinum resistance and prognosis in patients with high-grade serous ovarian cancer (HGSOC).

Results

The GEPIA dataset revealed the abundant expression of SLC7A1, SLC7A4, and SLC7A7, and conversely, the low expression of SLC7A2 and SLC7A8 in OC relative to normal tissue samples. Kaplan-Meier survival analysis further indicated that high SLC7A1 and low SLC7A2 mRNA levels were significantly associated with overall survival (P<0.05). Positive SLC7A1 expression was detected in 65 (58.1%) HGSOC tissue samples, but not in all normal ovarian tissue samples (100%), indicating that the expression of SLC7A1 in HGSOC tissues was significantly higher than that in normal ovarian tissues (P<0.001). Additionally, expression of SLC7A1 was negatively associated with relapse-free survival (RFS; P<0.05).

Conclusions

SLC7A1 is a potential prognostic biomarker of OC.

Multi-Omics and Informatics Analysis of FFPE Tissues Derived from Melanoma Patients with Long/Short Responses to Anti-PD1 Therapy Reveals Pathways of Response

Simple Summary

Immune based therapies have benefited many melanoma patients, but many patients still do not respond. This study analyzes biospecimens obtained from patients undergoing a type of immune based therapy called anti-PD-1 to understand mechanisms of response and resistance to this treatment. The operational definition of good response utilized in this investigation permitted us to examine the biochemical pathways that are facilitating anti-PD-1 responses independent of prior therapies received by patients. Currently, there are no clinically available tests to reliably test for the outcome of patients treated with anti-PD-1 therapy. The purpose of this study was to facilitate the development of prospective biomarker-directed trials to guide therapy, as even though the side effect profile is favorable for anti-PD-1 therapy, some patients do not respond to therapy with significant toxicity. Each patient may require testing for the pathways upregulated in the tumor to predict optimal benefit to anti-PD-1 treatment.

Abstract

Anti-PD-1 based immune therapies are thought to be dependent on antigen processing and presentation mechanisms. To characterize the immune-dependent mechanisms that predispose stage III/IV melanoma patients to respond to anti-PD-1 therapies, we performed a multi-omics study consisting of expression proteomics and targeted immune-oncology-based mRNA sequencing. Formalin-fixed paraffin-embedded tissue samples were obtained from stage III/IV patients with melanoma prior to anti-PD-1 therapy. The patients were first stratified into poor and good responders based on whether their tumors had or had not progressed while on anti-PD-1 therapy for 1 year. We identified 263 protein/gene candidates that displayed differential expression, of which 223 were identified via proteomics and 40 via targeted-mRNA analyses. The downstream analyses of expression profiles using MetaCore software demonstrated an enrichment of immune system pathways involved in antigen processing/presentation and cytokine production/signaling. Pathway analyses showed interferon (IFN)-γ-mediated signaling via NF-κB and JAK/STAT pathways to affect immune processes in a cell-specific manner and to interact with the inducible nitric oxide synthase. We review these findings within the context of available literature on the efficacy of anti-PD-1 therapy. The comparison of good and poor responders, using efficacy of PD-1-based therapy at 1 year, elucidated the role of antigen presentation in mediating response or resistance to anti-PD-1 blockade.

Expression and clinical significance of methyl-CpG binding domain protein 2 in high-grade serous ovarian cancer

Platinum resistance is an important cause of clinical recurrence and mortality of patients with high-grade serous ovarian cancer (HGSOC). Methyl-CpG binding domain protein 2 (MBD2) serves an important role in tumor progression; however, its role in HGSOC remains unclear. The aim of the present study was to investigate the expression of MBD2 in HGSOC and its role in drug resistance and prognosis of HGSOC. MBD2 expression was analyzed by immunohistochemical staining and western blotting. The associations between MBD2 expression and clinical pathological features, platinum resistance and patient prognosis were analyzed using a χ² test, Kaplan-Meier analysis and Cox regression analysis. Positive MBD2 expression was detected in 73 (63.5%) of the HGSOC tissue samples, whereas it was undetectable in all 16 normal tissue samples (100%) analyzed, indicating a significantly higher expression level in tumor tissues compared with normal tissues (P<0.001). Additionally, MBD2 expression was significantly higher in platinum-resistant cases compared with that in platinum-sensitive cases (P<0.05). In addition, high expression of MBD2 was negatively associated with relapse-free survival (P<0.05). In conclusion, MBD2 was demonstrated to be a potential drug target and a biomarker for poor prognosis in HGSOC.