Intracellular signal transduction pathway proteins as targets for cancer therapy

TFE3/PI3K/Akt/mTOR Axis in Renal Cell Carcinoma Affects Tumor Microenvironment

The role of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway in renal cell carcinoma (RCC) progression, metastasis, and resistance to therapies has not been investigated thoroughly. Transcription factor E3 (TFE3) expression is related to a poorer prognosis and tumor microenvironment in patients with RCC. This study aimed to determine the relationship between TFE3 and the PI3K/Akt pathway. TFE3 down-regulation was achieved by transient transfection of siRNA and shRNA in UOK146 cells. TFE3 overexpression was induced by transient transfection with pcDNA3.1 encoding the constitutively active form of TFE3. The cells were treated with mammalian target of rapamycin (mTOR) and PI3K inhibitors. Western blot was performed to detect TFE3, programmed death-ligand 1, phospho-Akt, and Akt. Phospho-Akt expression increased significantly upon TFE3 down-regulation, and decreased significantly upon up-regulation. When RCC cells were treated with a PI3K inhibitor (LY294002), TFE3 expression increased and phospho-Akt expression decreased. Data from this study indicate that TFE3 plays a role in the PI3K/Akt pathway in RCC. The results of this study suggest that PI3K/Akt inhibitors may aid in the treatment of patients with RCC by affecting the tumor microenvironment.

Circadian patterns of growth factor receptor-dependent signaling and implications for carcinogenesis

Several different signaling pathways that regulate cell proliferation and differentiation are initiated by binding of ligands to cell-surface and membrane-bound enzyme-linked receptors, such as receptor tyrosine kinases and serine-threonine kinases. They prompt phosphorylation of tyrosine and serine-threonine residues and initiate downstream signaling pathways and priming of intracellular molecules that convey the signal in the cytoplasm and nucleus, with transcriptional activation of specific genes enriching cell growth and survival-related cascades. These cell processes are rhythmically driven by molecular clockworks endowed in every cell type and when deregulated play a crucial role in cancer onset and progression. Growth factors and their matching receptor-dependent signaling are frequently overexpressed and/or dysregulated in many cancer types. In this review we focus on the interplay between biological clocks and Growth Factor Receptor-dependent signaling in the context of carcinogenesis.

Sulconazole induces PANoptosis by triggering oxidative stress and inhibiting glycolysis to increase radiosensitivity in esophageal cancer

Esophageal cancer is the seventh most common cancer in the world. Although traditional treatment methods such as radiotherapy and chemotherapy have good effects, their side effects and drug resistance remain problematic. The repositioning of drug function provides new ideas for the research and development of anticancer drugs. We previously showed that the Food and Drug Administration (FDA)-approved drug sulconazole can effectively inhibit the growth of esophageal cancer cells, but its molecular mechanism is not clear. Here, our study demonstrated that sulconazole had a broad spectrum of anticancer effects. It can not only inhibit the proliferation, but also inhibit the migration of esophageal cancer cells. Both transcriptomic sequencing and proteomic sequencing showed that sulconazole could promote various types of programmed cell death and inhibit glycolysis and its related pathways. Experimentally, we found that sulconazole induced apoptosis, pyroptosis, necroptosis and ferroptosis. Mechanistically, sulconazole triggered mitochondrial oxidative stress and inhibited glycolysis. Finally, we showed that low-dose sulconazole can increase radiosensitivity of esophageal cancer cells. Taken together, these new findings provide strong laboratory evidence for the clinical application of sulconazole in esophageal cancer.

A Biflavonoid-Rich Extract from Selaginella doederleinii Hieron. against Throat Carcinoma via Akt/Bad and IKKβ/NF-κB/COX-2 Pathways

Selaginella doederleinii Hieron. is a common pharmacological plant, and this folk herbal medicine and its complex preparations have been widely used for the treatment of throat carcinoma (TC) and several associated complications in traditional Chinese medicine. This study was aimed at investigating the specific anti-throat carcinoma impacts and potential mechanisms of a biflavonoid-rich extract from S. doederleinii (SD-BFRE). The phytochemical profiling of SD-BFRE was performed by HPLC-ESI-QTOF-MS and UPLC-PDA, and the detailed pharmacological effects and mechanisms were respectively evaluated in vitro and in vivo. MTT assay, the Transwell assay and flow cytometry were performed to evaluate the abilities of SD-BFRE on inhibiting cell infiltrative growth in TC cells (Hep-2 and FaDu) in in vitro experiments. In vivo experiments used Hep-2 tumor-bearing nude mice to evaluate the anti-TC effect of SD-BFRE. Western blotting was used to explore the potential apoptotic pathway of TC cells. Here, we found that SD-BFRE exhibited anti-proliferation and pro-apoptotic effects in TC cells. Mechanistic studies have identified that SD-BFRE can suppress the activity of IKKβ and IκB-α kinase and then down-regulate the effector proteins of NF-κB/COX-2 signaling. Moreover, SD-BFRE induced apoptosis partly by regulating the Akt/Bad/caspase signaling pathway. Taken together, this study firstly demonstrated that SD-BFRE exerted its anti-TC effects by way of IKKβ/NF-κB/COX-2 and Akt/Bad pathways and might represent a potential chemotherapeutic agent for throat carcinoma.

Quercetin induces autophagy-associated death in HL-60 cells through CaMKKβ/AMPK/mTOR signal pathway

Acute myeloid leukemia (AML) is one of the most common malignancies of the hematopoietic progenitor cell in adults. Quercetin has gained recognition over the years because of its anti-cancer effect with minimal toxicity. Herein, we aim to investigate the anti-leukemia mechanism of quercetin and to decipher the signaling pathway of quercetin in HL-60 leukemic cells. We observed that quercetin induces apoptosis and autophagic cell death, in which both pathways play an important role in suppressing the viability of leukemia cells. Phosphorylated AMPK (p-AMPK) protein expressions are lower in primary AML cells, HL-60 cells, KG-1 and THP-1 cells than in peripheral blood monocular cells. After quercetin treatment, the expression of p-AMPK is increased while the expression of p-mTOR is decreased in a dose-dependent manner. Mechanistically, compound C, an AMPK phosphorylation inhibitor, upregulates the phosphorylation of mTOR and inhibits autophagy and apoptosis in quercetin-induced HL-60 cells, while silencing of CaMKKβ inhibits the quercetin-induced phosphorylation of AMPK, resulting in increased mTOR phosphorylation. Furthermore, silencing of CaMKKβ inhibits the autophagy in HL-60 cells. Taken together, our data delineate that quercetin plays its anti-leukemia role by inhibiting cell viability and inducing apoptosis and autophagy in leukemia cells. Quercetin inhibits the phosphorylation of mTOR by regulating the activity of AMPK, thus playing a role in the regulation of autophagy and apoptosis. CaMKKβ is a potential upstream molecule for AMPK/mTOR signaling pathway, through which quercetin induces autophagy in HL-60 cells.

Deciphering the role of predicted miRNAs of polyomaviruses in carcinogenesis

Human polyomaviruses are relatively common in the general population. Polyomaviruses maintain a persistent infection after initial infection in childhood, acting as an opportunistic pathogen in immunocompromised populations and their association has been linked to carcinogenesis. A comprehensive understanding of the underlying molecular mechanisms of carcinogenesis in consequence of polyomavirus infection remains elusive. However, the critical role of viral miRNAs and their potential targets in modifying the transcriptome profile of the host remains largely unknown. Polyomavirus-derived miRNAs have the potential to play a substantial role in carcinogenesis. Employing computational approaches, putative viral miRNAs along with their target genes have been predicted and possible roles of the targeted genes in many significant biological processes have been obtained. Polyomaviruses have been observed to target intracellular signal transduction pathways through miRNA-mediated epigenetic regulation, which may contribute to cancer development. In addition, BKPyV-infected human renal cell microarray data was coupled with predicted target genes and analysis of the downregulated genes indicated that viruses target multiple signaling pathways (e.g. MAPK signaling pathway, PI3K-Akt signaling pathway, PPAR signaling pathway) in the host as well as turning off several tumor suppression genes (e.g. FGGY, EPHX2, CACNA2D3, CDH16) through miRNA-induced mechanisms, assuring cell transformation. This study provides a conceptual framework for the underlying molecular mechanisms involved in the course of carcinogenesis upon polyomavirus infection.

The Role of Periostin in Angiogenesis and Lymphangiogenesis in Tumors

Simple Summary

Cancers are common diseases that affect people of all ages worldwide. For this reason, continuous attempts are being made to improve current therapeutic options. The formation of metastases significantly decreases patient survival. Therefore, understanding the mechanisms that are involved in this process seems to be crucial for effective cancer therapy. Cancer dissemination occurs mainly through blood and lymphatic vessels. As a result, many scientists have conducted a number of studies on the formation of new vessels. Many studies have shown that proangiogenic factors and the extracellular matrix protein, i.e., periostin, may be important in tumor angio- and lymphangiogenesis, thus contributing to metastasis formation and worsening of the prognosis.

Abstract

Periostin (POSTN) is a protein that is part of the extracellular matrix (ECM) and which significantly affects the control of intracellular signaling pathways (PI3K-AKT, FAK) through binding integrin receptors (αvβ3, αvβ5, α6β4). In addition, increased POSTN expression enhances the expression of VEGF family growth factors and promotes Erk phosphorylation. As a result, this glycoprotein controls the Erk/VEGF pathway. Therefore, it plays a crucial role in the formation of new blood and lymphatic vessels, which may be significant in the process of metastasis. Moreover, POSTN is involved in the proliferation, progression, migration and epithelial-mesenchymal transition (EMT) of tumor cells. Its increased expression has been detected in many cancers, including breast cancer, ovarian cancer, non-small cell lung carcinoma and glioblastoma. Many studies have shown that this protein may be an independent prognostic and predictive factor in many cancers, which may influence the choice of optimal therapy.

Liquid-liquid phase separation in tumor biology

Liquid–liquid phase separation (LLPS) is a novel principle for explaining the precise spatial and temporal regulation in living cells. LLPS compartmentalizes proteins and nucleic acids into micron-scale, liquid-like, membraneless bodies with specific functions, which were recently termed biomolecular condensates. Biomolecular condensates are executors underlying the intracellular spatiotemporal coordination of various biological activities, including chromatin organization, genomic stability, DNA damage response and repair, transcription, and signal transduction. Dysregulation of these cellular processes is a key event in the initiation and/or evolution of cancer, and emerging evidence has linked the formation and regulation of LLPS to malignant transformations in tumor biology. In this review, we comprehensively summarize the detailed mechanisms of biomolecular condensate formation and biophysical function and review the recent major advances toward elucidating the multiple mechanisms involved in cancer cell pathology driven by aberrant LLPS. In addition, we discuss the therapeutic perspectives of LLPS in cancer research and the most recently developed drug candidates targeting LLPS modulation that can be used to combat tumorigenesis.

A novel intramolecular negative regulation of mouse Jak3 activity by tyrosine 820

Jak3, a member of the Janus kinase family, is essential for the cytokine receptor common gamma (γ) chain-mediated signaling. During activation of Jak3, tyrosine residues are phosphorylated and potentially regulate its kinase activity. We identified a novel tyrosine phosphorylation site within mouse Jak3, Y820, which is conserved in human Jak3, Y824. IL-2-induced tyrosine phosphorylation of Jak3 Y824 in human T cell line HuT78 cells was detected by using a phosphospecific, pY824, antibody. Mutation of mouse Jak3 Y820 to alanine (Y820A) showed increased autophosphorylation of Jak3 and enhanced STAT5 tyrosine phosphorylation and transcriptional activation. Stably expressed Jak3 Y820A in F7 cells, an IL-2 responsive mouse pro-B cell line Ba/F3, exhibited enhanced IL-2-dependent cell growth. Mechanistic studies demonstrated that interaction between Jak3 and STAT5 increased in Jak3 Y820A compared to Jak3 WT. These data suggest that Jak3 Y820 plays a role in negative regulation of Jak3-mediated STAT5 signaling cascade upon IL-2-stimulation. We speculate that this occurs through an interaction promoted by the tyrosine phosphorylated Y820 or a conformational change by Y820 mutation with either the STAT directly or with the recruitment of molecules such as phosphatases via a SH2 interaction. Additional studies will focus on these interactions as Jak3 plays a crucial role in disease and health.

Phase separation drives tumor pathogenesis and evolution: all roads lead to Rome

Cells coordinate numerous biochemical reactions in space and time, depending on the subdivision of the intracellular space into functional compartments. Compelling evidence has demonstrated that phase separation induces the formation of membrane-less compartments to partition intracellular substances in a strictly regulated manner and participates in various biological processes. Based on the strong association of cancer with the dysregulation of intracellular physiological processes and the occurrence of phase separation in cancer-associated condensates, phase separation undoubtedly plays a significant role in tumorigenesis. In this review, we summarize the drivers and functions of phase separation, elaborate on the roles of phase separation in tumor pathogenesis and evolution, and propose substantial research and therapeutic prospects for phase separation in cancer.

Possible Therapeutic Applications of Targeting STAP Proteins in Cancer

The signal-transducing adaptor protein (STAP) family, including STAP-1 and STAP-2, contributes to a variety of intracellular signaling pathways. The proteins in this family contain typical structures for adaptor proteins, such as Pleckstrin homology in the N-terminal regions and SRC homology 2 domains in the central regions. STAP proteins bind to inhibitor of kappaB kinase complex, breast tumor kinase, signal transducer and activator of transcription 3 (STAT3), and STAT5, during tumorigenesis and inflammatory/immune responses. STAP proteins positively or negatively regulate critical steps in intracellular signaling pathways through individually unique mechanisms. This article reviews the roles of the novel STAP family and the possible therapeutic applications of targeting STAP proteins in cancer.

The Role of mTOR Inhibitors in Hematologic Disease: From Bench to Bedside

The mTOR pathway plays a central role in many cellular processes, such as cellular growth, protein synthesis, glucose, and lipid metabolism. Aberrant regulation of mTOR is a hallmark of many cancers, including hematological malignancies. mTOR inhibitors, such as Rapamycin and Rapamycin analogs (Rapalogs), have become a promising class of agents to treat malignant blood diseases-either alone or in combination with other treatment regimens. This review highlights experimental evidence underlying the molecular mechanisms of mTOR inhibitors and summarizes their evolving role in the treatment of hematologic disease, including leukemia, lymphoma, myeloma, immune hemocytopenia, and graft-versus-host disease (GVHD). Based on data presented in this review, we believe that mTOR inhibitors are becoming a trusted therapeutic in the clinical hematologist's toolbelt and should be considered more routinely in combination therapy for the management of hematologic disease.

Targeted therapy for metastatic renal cell carcinoma

BACKGROUND

Several comparative randomised controlled trials (RCTs) have been performed including combinations of tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors since the publication of a Cochrane Review on targeted therapy for metastatic renal cell carcinoma (mRCC) in 2008. This review represents an update of that original review.

OBJECTIVES

To assess the effects of targeted therapies for clear cell mRCC in patients naïve to systemic therapy.

SEARCH METHODS

We performed a comprehensive search with no restrictions on language or publication status. The date of the latest search was 18 June 2020.

SELECTION CRITERIA

We included randomised controlled trials, recruiting patients with clear cell mRCC naïve to previous systemic treatment. The index intervention was any TKI-based targeted therapy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the included studies and extracted data for the primary outcomes: progression-free survival (PFS), overall survival (OS) and serious adverse events (SAEs); and the secondary outcomes: health-related quality of life (QoL), response rate and minor adverse events (AEs). We performed statistical analyses using a random-effects model and rated the certainty of evidence according to the GRADE approach.

MAIN RESULTS

We included 18 RCTs reporting on 11,590 participants randomised across 18 comparisons. This abstract focuses on the primary outcomes of select comparisons. 1. Pazopanib versus sunitinib Pazopanib may result in little to no difference in PFS as compared to sunitinib (hazard ratio (HR) 1.05, 95% confidence interval (CI) 0.90 to 1.23; 1 study, 1110 participants; low-certainty evidence). Based on the control event risk of 420 per 1000 in this trial at 12 months, this corresponds to 18 fewer participants experiencing PFS (95% CI 76 fewer to 38 more) per 1000 participants. Pazopanib may result in little to no difference in OS compared to sunitinib (HR 0.92, 95% CI 0.80 to 1.06; 1 study, 1110 participants; low-certainty evidence). Based on the control event risk of 550 per 1000 in this trial at 12 months, this corresponds to 27 more OSs (95% CI 19 fewer to 70 more) per 1000 participants. Pazopanib may result in little to no difference in SAEs as compared to sunitinib (risk ratio (RR) 1.01, 95% CI 0.94 to 1.09; 1 study, 1102 participants; low-certainty evidence). Based on the control event risk of 734 per 1000 in this trial, this corresponds to 7 more participants experiencing SAEs (95% CI 44 fewer to 66 more) per 1000 participants. 2. Sunitinib versus avelumab and axitinib Sunitinib probably reduces PFS as compared to avelumab plus axitinib (HR 1.45, 95% CI 1.17 to 1.80; 1 study, 886 participants; moderate-certainty evidence). Based on the control event risk of 550 per 1000 in this trial at 12 months, this corresponds to 130 fewer participants experiencing PFS (95% CI 209 fewer to 53 fewer) per 1000 participants. Sunitinib may result in little to no difference in OS (HR 1.28, 95% CI 0.92 to 1.79; 1 study, 886 participants; low-certainty evidence). Based on the control event risk of 890 per 1000 in this trial at 12 months, this would result in 29 fewer OSs (95% CI 78 fewer to 8 more) per 1000 participants. Sunitinib may result in little to no difference in SAEs (RR 1.01, 95% CI 0.93 to 1.10; 1 study, 873 participants; low-certainty evidence). Based on the control event risk of 705 per 1000 in this trial, this corresponds to 7 more SAEs (95% CI 49 fewer to 71 more) per 1000 participants.  3. Sunitinib versus pembrolizumab and axitinib Sunitinib probably reduces PFS as compared to pembrolizumab plus axitinib (HR 1.45, 95% CI 1.19 to 1.76; 1 study, 861 participants; moderate-certainty evidence). Based on the control event risk of 590 per 1000 in this trial at 12 months, this corresponds to 125 fewer participants experiencing PFS (95% CI 195 fewer to 56 fewer) per 1000 participants. Sunitinib probably reduces OS (HR 1.90, 95% CI 1.36 to 2.65; 1 study, 861 participants; moderate-certainty evidence). Based on the control event risk of 880 per 1000 in this trial at 12 months, this would result in 96 fewer OSs (95% CI 167 fewer to 40 fewer) per 1000 participants. Sunitinib may reduce SAEs as compared to pembrolizumab plus axitinib (RR 0.90, 95% CI 0.81 to 1.02; 1 study, 854 participants; low-certainty evidence) although the CI includes the possibility of no effect. Based on the control event risk of 604 per 1000 in this trial, this corresponds to 60 fewer SAEs (95% CI 115 fewer to 12 more) per 1000 participants.  4. Sunitinib versus nivolumab and ipilimumab Sunitinib may reduce PFS as compared to nivolumab plus ipilimumab (HR 1.30, 95% CI 1.11 to 1.52; 1 study, 847 participants; low-certainty evidence). Based on the control event risk of 280 per 1000 in this trial at 30 months' follow-up, this corresponds to 89 fewer PFSs (95% CI 136 fewer to 37 fewer) per 1000 participants. Sunitinib reduces OS (HR 1.52, 95% CI 1.23 to 1.89; 1 study, 847 participants; high-certainty evidence). Based on the control event risk 600 per 1000 in this trial at 30 months, this would result in 140 fewer OSs (95% CI 219 fewer to 67 fewer) per 1000 participants. Sunitinib probably increases SAEs (RR 1.37, 95% CI 1.22 to 1.53; 1 study, 1082 participants; moderate-certainty evidence). Based on the control event risk of 457 per 1000 in this trial, this corresponds to 169 more SAEs (95% CI 101 more to 242 more) per 1000 participants.

AUTHORS' CONCLUSIONS

Based on the low to high certainty of evidence, several combinations of immune checkpoint inhibitors appear to be superior to single-agent targeted therapy in terms of PFS and OS, and with a favourable AE profile. Some single-agent targeted therapies demonstrated a similar or improved oncological outcome compared to others; minor differences were observed for AE within this group. The certainty of evidence was variable ranging from high to very low and all comparisons were based on single trials.

Screening of key genes associated with R‑CHOP immunochemotherapy and construction of a prognostic risk model in diffuse large B‑cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a common subtype of non-Hodgkin lymphoma, which is curable in the majority of patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) immunochemotherapy. However, the therapeutic mechanism of R-CHOP has not been elucidated. The GSE32918 and GSE57611 datasets were retrieved from The Gene Expression Omnibus database. The differentially expressed genes (DEGs) associated with R-CHOP therapy were identified using limma. Combined with prognostic information in GSE32918, DEGs found to be significantly associated with prognosis were selected using univariate Cox regression analysis and a risk prediction model was constructed. Based on this model, the samples in the training set (GSE32918) were divided into high and low risk score groups according to the median risk score. A total of 801 DEGs were identified between the R-CHOP treated DLBCL and primary DLBCL samples, from this 116 prognosis-associated genes were selected. Using Cox proportional hazards model, an optimal combination of 12 genes [including calcium/calmodulin dependent protein kinase I (CAMK1), hippocalcin like 4 (HPCAL4) and ephrin A5 (EFNA5)] was selected, and the sample risk score prediction model was constructed and validated. The DEGs between high risk score and low risk score groups were significantly enriched in functions associated with ‘response to DNA damage stimulus’, and pathways including ‘cytokine-cytokine receptor interaction’ and ‘cell cycle’. The optimal combination of the 12 genes, including CAMK1, HPCAL4 and EFNA5, was found to be useful in predicting the prognosis of patients with DLBCL after R-CHOP treatment. Therefore, these genes may be affected by R-CHOP in DLBCL.

Apoptosis-promoting and migration-suppressing effect of alantolactone on gastric cancer cell lines BGC-823 and SGC-7901 via regulating p38MAPK and NF-κB pathways

BACKGROUND

Gastric cancer is a malignant tumor with high incidence rate and mortality rate.

PURPOSE

In this study, we investigated the anti-cancer effect of alantolactone, a sesquiterpene lactone, on gastric cancer cell lines BGC-823 and SGC-7901.

METHODS

BGC-823 and SGC-7901 cells were treated with different concentrations of alantolactone, Hoechst 33258 staining, flow cytometry, wound healing assay, invasion assay, colony forming assay, quantative polymerase chain reaction, and western blot analysis were used to evaluate the anticancer activity of alantolactone to gastric cancer.

RESULTS

Alantolactone induced apoptosis of gastric cancer cells by regulating the expression of Bax, Bcl-2, and p53, which related to intrinsic apoptotic pathway, and suppressed colony formation, migration, and invasion by mediating the expression of matrix metalloproteinase (MMP)-2, MMP-7, and MMP-9. Cell signaling pathway analysis showed that alantolactone enhanced the phosphorylation of p38 and decreased the translocation of nucleus p65, suggesting that the apoptosis-promoting and migration-suppressing effect of alantolactone might at least partially rely on regulating p38 mitogen-activated protein kinase (p38MAPK) pathway and nuclear factor-κB (NF-κB) pathway.

CONCLUSIONS

Alantolactone can be used as a potential therapeutic agent for treating gastric cancer.

Fuplatin: An Efficient and Low-Toxic Dual-Prodrug

As FDA-approved chemotherapeutic agents, cisplatin, oxaliplatin, and 5-fluorouracil are widely used in clinic but limited by severe side-effects. To ameliorate their respective defects, a series of "dual-prodrug" by linking oxoplatin and 5-FU were designed and synthesized. The assembled compounds 10-17, named Fuplatin, exhibited much higher cytotoxicity against the tested cancer cells while lower cytotoxicity toward the human normal lung cells than free drugs or their combinations. Among them, 14 enhanced cellular accumulation with 62- and 825-fold amount of oxaliplatin and 8 at 9 h, respectively, significantly induced DNA damage and cell apoptosis, and inhibited migration and invasion in HCT-116 cells. Compound 14 arrested the cell cycle at S and G2 phases and up-regulated thymidylate synthase and p53, consistent with the results of the combination, suggesting 14 adopted a collaborative mode of 5-FU and oxaliplatin to kill cancer cells. In vivo, compound 14 showed high antitumor effect and no observable toxicity in NOD/SCID mice bearing HCT-116 tumors.

Role of the NFκB-signaling pathway in cancer

Cancer is a group of cells that malignantly grow and proliferate uncontrollably. At present, treatment modes for cancer mainly comprise surgery, chemotherapy, radiotherapy, molecularly targeted therapy, gene therapy, and immunotherapy. However, the curative effects of these treatments have been limited thus far by specific characteristics of tumors. Abnormal activation of signaling pathways is involved in tumor pathogenesis and plays critical roles in growth, progression, and relapse of cancers. Targeted therapies against effectors in oncogenic signaling have improved the outcomes of cancer patients. NFκB is an important signaling pathway involved in pathogenesis and treatment of cancers. Excessive activation of the NFκB-signaling pathway has been documented in various tumor tissues, and studies on this signaling pathway for targeted cancer therapy have become a hot topic. In this review, we update current understanding of the NFκB-signaling pathway in cancer.

Advanced malignancies treated with a combination of the VEGF inhibitor bevacizumab, anti-EGFR antibody cetuximab, and the mTOR inhibitor temsirolimus

BACKGROUND

Bevacizumab and temsirolimus are active agents in advanced solid tumors. Temsirolimus inhibits mTOR in the PI3 kinase/AKT/mTOR pathway as well as CYP2A, which may be a resistance mechanism for cetuximab. In addition, temsirolimus attenuates upregulation of HIF-1α levels, which may be a resistance mechanism for bevacizumab.

RESULTS

The median age of patients was 60 years (range, 23-80 years). The median number of prior systemic therapies was 3 (range, 1-6). The maximum tolerated dose (MTD) was determined to be bevacizumab 10 mg/kg biweekly, temsirolimus 5 mg weekly and cetuximab 100/75 mg/m2 weekly. Grade 3 or 4 toxicities were seen in 52% of patients with the highest prevalence being hyperglycemia (14%) and hypophosphatemia (14%). Eighteen of the 21 patients were evaluable for response. Three patients were taken off the study before restaging for toxicities. Partial response (PR) was observed in 2/18 patients (11%) and stable disease (SD) lasting ≥ 6 months was observed in 4/18 patients (22%) (total = 6/18 (33%)). In 8 evaluable patients with squamous cell carcinoma of the head and neck (HNSCC) there were partial responses in 2/8 (25%) patients and SD ≥ 6 months in 1/8 (13%) patients (total = 3/8, (38%)).

PATIENTS AND METHODS

We analyzed safety and responses in 21 patients with advanced solid tumors treated with bevacizumab, cetuximab, and temsirolimus.

CONCLUSION

The combination of bevacizumab, cetuximab, and temsirolimus showed activity in HNSCC; however, there were numerous toxicities reported, which will require careful management for future clinical development.

A single amino acid substitution confers B-cell clonogenic activity to the HIV-1 matrix protein p17

Recent data highlight the presence, in HIV-1-seropositive patients with lymphoma, of p17 variants (vp17s) endowed with B-cell clonogenicity, suggesting a role of vp17s in lymphomagenesis. We investigated the mechanisms responsible for the functional disparity on B cells between a wild-type p17 (refp17) and a vp17 named S75X. Here, we show that a single Arginine (R) to Glycine (G) mutation at position 76 in the refp17 backbone (p17R76G), as in the S75X variant, is per se sufficient to confer a B-cell clonogenic potential to the viral protein and modulate, through activation of the PTEN/PI3K/Akt signaling pathway, different molecules involved in apoptosis inhibition (CASP-9, CASP-7, DFF-45, NPM, YWHAZ, Src, PAX2, MAPK8), cell cycle promotion and cancer progression (CDK1, CDK2, CDK8, CHEK1, CHEK2, GSK-3 beta, NPM, PAK1, PP2C-alpha). Moreover, the only R to G mutation at position 76 was found to strongly impact on protein folding and oligomerization by altering the hydrogen bond network. This generates a conformational shift in the p17 R76G mutant which enables a functional epitope(s), masked in refp17, to elicit B-cell growth-promoting signals after its interaction with a still unknown receptor(s). Our findings offer new opportunities to understand the molecular mechanisms accounting for the B-cell growth-promoting activity of vp17s.

Clinicopathological and prognostic significance of mTOR and phosphorylated mTOR expression in patients with esophageal squamous cell carcinoma: a systematic review and meta-analysis

BACKGROUND

Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase responsible for regulating ribosomal biogenesis and protein synthesis. Dysregulation of mTOR contributes to tumorigenesis, angiogenesis, cellular growth and metastasis but its roles in esophageal squamous cell carcinoma (ESCC) are controversial. Therefore, the objective of this study is to evaluate the prognostic and clinicopathological significance of mTOR/p-mTOR expression in ESCC.

METHODS

Literature retrieval was conducted by searching PubMed, EMBASE and the Web of Science for full-text papers that met our eligibility criteria. Odds ratio (OR) and hazard ratio (HR) with 95 % confidence interval (CI) served as the appropriate summarized statistics for assessments of clinicopathological and prognostic significance, respectively. Cochrane Q-test and I²-statistic were adopted to estimate the heterogeneity level between studies. Potential publication bias was detected by Begg's test and Egger's test.

RESULTS

A total of 915 ESCC patients from nine original articles were included into this meta-analysis. The pooled analyses suggested that mTOR/p-mTOR expression was significantly correlated with the unfavorable outcomes of differentiation degree (OR: 2.63; 95 % CI: 1.71-4.05; P = 0.001), tumor invasion (OR: 1.48; 95 % CI: 1.02-2.13; P = 0.037), TNM stage (OR: 2.25; 95 % CI: 1.05-4.82; P = 0.037) and lymph node metastasis (OR: 1.82; 95 % CI: 1.06-3.11; P = 0.029), but had no significant relationship to the genders (OR: 0.81; 95 % CI: 0.50-1.32; P = 0.396). Moreover, mTOR/p-mTOR expression could independently predict the worse overall survival (HR: 2.04; 95 % CI: 1.58-2.62; P < 0.001), disease-free survival (HR: 2.39; 95 % CI: 1.64-3.49; P < 0.001) and cancer-specific survival (HR: 1.62; 95 % CI: 1.18-2.23; P = 0.003) of patients with ESCC. Such prognostic value of mTOR was not substantially altered by further subgroup analyses.

CONCLUSIONS

Positive expression of mTOR and p-mTOR was significantly associated with the unfavorable conditions on the depth of tumor invasion, TNM stage, differentiation degree and lymph node metastasis. mTOR and p-mTOR could serve as a valuable predictor for the poor prognosis of ESCC. More high-quality worldwide studies performing a multivariate analysis based on larger sample size are urgently required for further verifying and modifying our findings in the future.

Novel phase I study combining G1 phase, S phase, and G2/M phase cell cycle inhibitors in patients with advanced malignancies

PURPOSE

Cancer is a manifestation of aberrant cellular proliferation, and the cell cycle is one of the most successfully drugged targets in oncology. No prior study has been reported that simultaneously targets the 3 principal cell cycle phases populated by proliferating cells--G1, S, and G2/M.

METHODS

Temsirolimus (G1 inhibitor), topotecan (S inhibitor), and bortezomib (G2/M inhibitor) were administered in combination to patients with advanced malignancies using a 3+3 dose escalation schedule to assess the safety and establish the maximum tolerated dose (primary endpoints) of this cell cycle targeting approach. An in silico pharmacodynamic model using established effects of each of these agents on the cell cycle was used to validate the regimen and to guide the dosing regimen.

RESULTS

Sixty-two subjects were enrolled. The most common adverse events and dose-limiting toxicities were cytopenias, consistent with the cell cycle targeting approach employed. All cytopenias resolved to baseline values upon holding study drug administration. The maximum tolerated dose was temsirolimus 15 mg/kg IV D1, 8, 15; topotecan 2.8 mg/m(2) IV D1, 8; and bortezomib 0.6 mg/m2 IV D1, 4, 8, 11 [DOSAGE ERROR CORRECTED] of a 21-day cycle. In silico modeling suggests the regimen induces cell population shifts from G2/M and S phases to G1 phase and the quiescent G0 phase. Eighteen percent of subjects (11/62) achieved partial response (n = 2, serous ovarian and papillary thyroid) or stable disease for > 6 months (n = 9).

CONCLUSION

Combining drugs with inhibitory activity of G1 phase, S phase, and G2/M phase is safe and warrants further evaluation.

A multicenter phase II study of sorafenib in combination with erlotinib in patients with advanced non-small cell lung cancer (KCSG-0806)

OBJECTIVES

Sorafenib and erlotinib are potent, orally administered receptor tyrosine kinase inhibitors with antiproliferative and antiangiogenic activities. Given their synergistic activity in combination, we conducted a phase II study to determine the clinical activity of sorafenib in combination with erlotinib in patients with advanced non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Patients with advanced NSCLC who have received one or two prior chemotherapy regimens for metastatic disease, ECOG 0-2, and adequate organ function were eligible. Patients received 400mg twice daily sorafenib and 150 mg daily erlotinib in 28-day cycles. Epidermal growth factor receptor mutation and its downstream pathways were analyzed from available tumor samples. Changes in plasma cytokine and angiogenic factors were correlated with clinical outcomes.

RESULTS

A total of 46 patients were enrolled. Twenty patients (43%) were never smokers and 35 patients (75%) had adenocarcinoma histology. The overall response rate was 30.4%. Response to sorafenib/erlotinib was observed more commonly in patients with EGFR mutation than in those with EGFR wild type (WT) or EGFR unknown tumors (62.5% vs. 6.7% vs. 34.8%; P=0.013). Likewise, DCR was higher among patients with EGFR mutation than in those with EGFR WT or EGFR unknown tumors (87.5% vs. 46.7% vs. 60.9%; P=0.161). The most frequent adverse events (AEs) of all grades were hand-foot skin reaction (67.4%) followed by acneiform rash (58.7%).

CONCLUSION

Sorafenib combined with erlotinib is well-tolerated with manageable toxicity and appears to be effective against advanced NSCLC with one or two prior line of systemic treatment (NCT00801385).

Molecular concept in human oral cancer

The incidence of oral cancer remains high in both Asian and Western countries. Several risk factors associated with development of oral cancer are now well-known, including tobacco chewing, smoking, and alcohol consumption. Cancerous risk factors may cause many genetic events through chromosomal alteration or mutations in genetic material and lead to progression and development of oral cancer through histological progress, carcinogenesis. Oral squamous carcinogenesis is a multistep process in which multiple genetic events occur that alter the normal functions of proto-oncogenes/oncogenes and tumor suppressor genes. Furthermore, these gene alterations can deregulate the normal activity such as increase in the production of growth factors (transforming growth factor-α [TGF-α], TGF-β, platelet-derived growth factor, etc.) or numbers of cell surface receptors (epidermal growth factor receptor, G-protein-coupled receptor, etc.), enhanced intracellular messenger signaling and mutated production of transcription factors (ras gene family, c-myc gene) which results disturb to tightly regulated signaling pathways of normal cell. Several oncogenes and tumor suppressor genes have been implicated in oral cancer especially cyclin family, ras, PRAD-1, cyclin-dependent kinase inhibitors, p53 and RB1. Viral infections, particularly with oncogenic human papilloma virus subtype (16 and 18) and Epstein-Barr virus have tumorigenic effect on oral epithelia. Worldwide, this is an urgent need to initiate oral cancer research programs at molecular and genetic level which investigates the causes of genetic and molecular defect, responsible for malignancy. This approach may lead to development of target dependent tumor-specific drugs and appropriate gene therapy.

Gγ recruitment systems specifically select PPI and affinity-enhanced candidate proteins that interact with membrane protein targets

Protein-protein interactions (PPIs) are crucial for the vast majority of biological processes. We previously constructed a Gγ recruitment system to screen PPI candidate proteins and desirable affinity-altered (affinity-enhanced and affinity-attenuated) protein variants. The methods utilized a target protein fused to a mutated G-protein γ subunit (Gγ_cyto) lacking the ability to localize to the inner leaflet of the plasma membrane. However, the previous systems were adapted to use only soluble cytosolic proteins as targets. Recently, membrane proteins have been found to form the principal nodes of signaling involved in diseases and have attracted a great deal of interest as primary drug targets. Here, we describe new protocols for the Gγ recruitment systems that are specifically designed to use membrane proteins as targets to overcome previous limitations. These systems represent an attractive approach to exploring novel interacting candidates and affinity-altered protein variants and their interactions with proteins on the inner side of the plasma membrane, with high specificity and selectivity.

Cushing's disease: current medical therapies and molecular insights guiding future therapies

OBJECT Cushing's disease (CD) can lead to significant morbidity secondary to hormonal sequelae or mass effect from the pituitary tumor. A transsphenoidal approach to resection of the adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma is the first-line treatment. However, in the setting in which patients are unable to undergo surgery, have acute hypercortisolism, or have recurrent disease, medical therapy can play an important role. The authors performed a systematic review to highlight the efficacy of medical treatment of CD and discuss novel molecular insights that could guide the development of future medical treatments of CD. METHODS A search on current medical therapies for CD was performed. After individual medical therapeutic agents for CD were identified, each agent underwent a formal systematic search. The phrase "(name of agent) and Cushing's" was used as a search term in PubMed for all years up to 2014. The abstract of each article was reviewed for studies that evaluated the efficacy of medical treatment of CD. Only studies that enrolled at least 20 patients were included in the review. RESULTS A total of 11 articles on 6 individual agents were included in this review. Specific medical therapies were categorized based on the level of action: pituitary directed (cabergoline and pasireotide), adrenal/steroidogenesis directed (ketoconazole, metyrapone, and mitotane), and end-tissue directed/cortisol receptors (mifepristone). The studies identified consisted of a mix of retrospective reviews and small clinical trials. Only pasireotide and mifepristone have undergone Phase III clinical trials, from which they garnered FDA approval for the treatment of patients with CD. Overall, agents targeting ACTH secretion and steroidogenesis were found to be quite effective in reducing urine free cortisol (UFC) to levels near normal. A significant reduction in UFC was observed in 45%-100% of patients and a majority of patients gained clinical improvement. Similarly, inhibition at the end-tissue level led to clinical improvement in 87% of patients. However, side-effect rates associated with these drugs are high (up to 88%). Ketoconazole has been shown to enhance tumor appearance on MRI to facilitate pituitary resection. Promising molecular targets have been identified, including epidermal growth factor receptor, retinoic acid receptors, and cyclin dependent kinases. These pathways have been linked to the regulation of pro-opiomelanocortin expression, ACTH secretion, and tumor growth. CONCLUSIONS Despite encouraging Phase III clinical trials leading to FDA approval of 2 agents for treatment of patients with CD, no agent has yet produced results comparable to resection. As a result, the molecular insights gained into CD pathogenesis will need to continue to be expanded until they can lead to the development of medical therapies for CD with a favorable side-effect profile and efficacy comparable to resection. Ideally these agents should also reduce tumor size, which could potentially permit their eventual discontinuation.

Macrolide analog F806 suppresses esophageal squamous cell carcinoma (ESCC) by blocking β1 integrin activation

The paucity of new drugs for the treatment of esophageal squamous cell carcinoma (ESCC) limits the treatment options. This study characterized the therapeutic efficacy and action mechanism of a novel natural macrolide compound F806 in human ESCC xenograft models and cell lines. F806 inhibited growth of ESCC, most importantly, it displayed fewer undesirable side effects on normal tissues in two human ESCC xenograft models. F806 inhibited proliferation of six ESCC cells lines, with the half maximal inhibitory concentration (IC50) ranging from 9.31 to 16.43 μM. Furthermore, F806 induced apoptosis of ESCC cells, contributing to its growth-inhibitory effect. Also, F806 inhibited cell adhesion resulting in anoikis. Mechanistic studies revealed that F806 inhibited the activation of β1 integrin in part by binding to a novel site Arg610 of β1 integrin, suppressed focal adhesion formation, decreased cell adhesion to extracellular matrix and eventually triggered apoptosis. We concluded that F806 would potentially be a well-tolerated anticancer drug by targeting β1 integrin, resulting in anoikis in ESCC cells.

Quinaldic acid inhibits proliferation of colon cancer ht-29 cells in vitro: effects on signaling pathways

Quinaldic acid is presumed to be a derivative of kynurenic acid, a tryptophan metabolite with proven antiproliferative activity towards cancer cells in vitro. The aim of present study was to evaluate the activity of quinaldic acid in colon cancer cells. The antiproliferative potential of quinaldic acid was assessed in HT-29, LS180 and Caco-2 cells. Suppression of metabolic activity (IC50 of 0.5mM for HT-29 and LS180 cells, 0.9mM for Caco-2 cells) and DNA synthesis (IC50 of 2.7, 4.3, 2mM for HT-29, LS180 and Caco-2 cells, respectively) were observed in all tested cell lines. It is noteworthy that quinaldic acid in antiproliferative concentrations was non-toxic to normal colon epithelium CCD 841 CoTr cells. Concomitantly, alterations in several signaling pathways in HT-29 cells were observed. Quinaldic acid led to changes in the phosphorylation level of extracellular-signal-regulated kinase (ERK) 1/2, p38, cAMP response element-binding protein (CREB) and Akt (protein kinase B) kinases. Moreover, changes in the CREB transcription factor were also found at the gene expression level. Antiproliferative activity and signaling pathways modulatory potential of quinaldic acid in colon cancer cells in vitro has been stated.

Exploration of Aspergillus fumigatus Ras pathways for novel antifungal drug targets

Ras pathway signaling is a critical virulence determinant for pathogenic fungi. Localization of Ras to the plasma membrane (PM) is required for Ras network interactions supporting fungal growth and virulence. For example, loss of Aspergillus fumigatus RasA signaling at the PM via inhibition of palmitoylation leads to decreased growth, altered hyphal morphogenesis, decreased cell wall integrity and loss of virulence. In order to be properly localized and activated, Ras proteins must transit a series of post-translational modification (PTM) steps. These steps include farnesylation, proteolytic cleavage of terminal amino acids, carboxymethylation, and palmitoylation. Because Ras activation drives tumor development, Ras pathways have been extensively studied in mammalian cells as a potential target for anti-cancer therapy. Inhibitors of mammalian Ras interactions and PTM components have been, or are actively being, developed. This review will focus on the potential for building upon existing scaffolds to exploit fungal Ras proteins for therapy, synthesizing data from studies employing both mammalian and fungal systems.

Induction of BCL2-Interacting Killer, BIK, is Mediated for Anti-Cancer Activity of Curcumin in Human Head and Neck Squamous Cell Carcinoma Cells

Naturally occurring diarylheptanoid curcumin (CUR), a principal component of the Asian spice turmeric, has been shown to have anti-cancer effects in many tumor types. However, a detailed mechanism regarding CUR induced tumor cell killing remain to be comprehensively explored. Using two head neck squamous cell carcinoma (HNSCC) cell lines FaDu (hypopharyngeal) and Cal27 (tongue), we demonstrated a novel mechanism by which CUR levies the cytotoxic effect. We found that CUR induced upregulation of pro-apoptotic Bik, down-regulation of survival signaling by AKT and NF-κB prior to the induction of the caspase-cascade reduction of cell proliferation, are primary mechanisms of CUR-induced cell death, thus providing insights into the anti-tumor activity of CUR in HNSCC cells.

Advanced gynecologic malignancies treated with a combination of the VEGF inhibitor bevacizumab and the mTOR inhibitor temsirolimus

Background: Bevacizumab and temsirolimus are active agents in gynecologic tumors. Temsirolimus attenuates upregulation of HIF-1α levels, a resistance mechanism for antiangiogenics, and targets the PI3-kinase/AKT/mTOR axis, commonly aberrant in these tumors

Patients and Methods: We analyzed safety and responses in 41 patients with gynecologic cancers treated as part of a Phase I study of bevacizumab and temsirolimus.

Results: Median age of the 41 women was 60 years (range, 33-80 years); median number of prior systemic therapies was 4 (1-11). Grade 3 or 4 treatment-related toxicities included: thrombocytopenia (10%), mucositis (2%), hypertension (2%), hypercholesterolemia (2%), fatigue (7%), elevated aspartate aminotransferase (2%), and neutropenia (2%). Twenty-nine patients (71%) experienced no treatment-related toxicity greater than grade 2. Full FDA-approved doses of both drugs (bevacizumab 15mg/kg IV Q3weeks and temsirolimus 25mg IV weekly) were administered without dose-limiting toxicity. Eight patients (20%) achieved stable disease (SD) ≥ 6 months and 7 patients (17%), a partial response (PR) [total = 15/41 patients (37%)]. Eight of 13 patients (62%) with high-grade serous histology (ovarian or primary peritoneal) achieved SD ≥ 6 months/PR.

Conclusion: Bevacizumab and temsirolimus was well tolerated. Thirty-seven percent of heavily-pretreated patients achieved SD ≥ 6 months/PR, suggesting that this combination warrants further study.

Role of the ERK1/2 pathway in tumor chemoresistance and tumor therapy

Chemotherapy is one of the important methods for treatment in tumors. However, many tumor patients may experience tumor recurrence because of treatment failure due to chemoresistance. Although many signaling pathways could influence chemoresistance of tumor cells, the extracellular signal-regulated kinase 1 and 2 (ERK1/2) pathway has gained significant attention because of its implications in signaling and which has crosstalk with other signaling pathways. Extensive studies conclude that ERK1/2 pathway is responding to chemoresistance in many kinds of malignant tumors. The aim of this review is to discuss on the role of ERK1/2 pathway in chemoresistance and therapy of tumors. A comprehensive understanding of ERK1/2 pathway in chemoresistance of tumors could provide novel avenues for treatment strategies of tumors.

An optical labeling-based proliferation assay system reveals the paracrine effect of interleukin-6 in breast cancer

Proliferation analysis is one of the basic approaches to characterize various cell types. In conventional cell proliferation assays, the same sample cannot be observed over time, nor can a specific group within a heterogeneous population of cells, for example, cancerous cells, be analyzed separately. To overcome these limitations, we established an optical labeling-based proliferation assay system with the Kaede protein, whose fluorescence can be irreversibly photo converted from green to red by irradiation. After a single non-toxic photoconversion event, the intensity of red fluorescence in each cell is reduced by cell division. From this, we developed a simple method to quantify cell proliferation by monitoring reduction of red fluorescence over time. This study shows that the optical labeling-based proliferation assay is a viable novel method to analyze cell proliferation, and could enhance our understanding of mechanisms regulating cell proliferation machinery. We used this newly established system to analyze the functions of secreted interleukin-6 (IL-6) in cancer cell proliferation, which had not been fully characterized. Reduction in proliferation was observed following IL-6 knockdown. However, after co-culturing with IL-6-expressing cells, the proliferation of Kaede-labeled IL-6-knockdown cells was restored. These data indicate that in basal-like breast cancer cells, IL-6 exhibits a paracrine effect to positively regulate cell proliferation. Our results thus demonstrate that cancer cells can secrete signaling molecules, such as IL-6, to support the proliferation of other cancer cells.

Mycobacterium bovis BCG promotes tumor cell survival from tumor necrosis factor-α-induced apoptosis

Background

Increased incidence of lung cancer among pulmonary tuberculosis patients suggests mycobacteria-induced tumorigenic response in the host. The alveolar epithelial cells, candidate cells that form lung adenocarcinoma, constitute a niche for mycobacterial replication and infection. We thus explored the possible mechanism of M. bovis Bacillus Calmette-Guérin (BCG)-assisted tumorigenicity in type II epithelial cells, human lung adenocarcinoma A549 and other cancer cells.

Methods

Cancer cell lines originating from lung, colon, bladder, liver, breast, skin and cervix were treated with tumor necrosis factor (TNF)-α in presence or absence of BCG infection. p53, COP1 and sonic hedgehog (SHH) signaling markers were determined by immunoblotting and luciferase assays, and quantitative real time PCR was done for p53-responsive pro-apoptotic genes and SHH signaling markers. MTT assays and Annexin V staining were utilized to study apoptosis. Gain- and loss-of-function approaches were used to investigate the role for SHH and COP1 signaling during apoptosis. A549 xenografted mice were used to validate the contribution of BCG during TNF-α treatment.

Results

Here, we show that BCG inhibits TNF-α-mediated apoptosis in A549 cells via downregulation of p53 expression. Substantiating this observation, BCG rescued A549 xenografts from TNF-α-mediated tumor clearance in nude mice. Furthermore, activation of SHH signaling by BCG induced the expression of an E3 ubiquitin ligase, COP1. SHH-driven COP1 targeted p53, thereby facilitating downregulation of p53-responsive pro-apoptotic genes and inhibition of apoptosis. Similar effects of BCG could be shown for HCT116, T24, MNT-1, HepG2 and HELA cells but not for HCT116 p53^-/- and MDA-MB-231 cells.

Conclusion

Our results not only highlight possible explanations for the coexistence of pulmonary tuberculosis and lung cancer but also address probable reasons for failure of BCG immunotherapy of cancers.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-210) contains supplementary material, which is available to authorized users.

Novel therapies for meningiomas

Although advances in surgery, radiation therapy and stereotactic radiosurgery have significantly improved the treatment of meningiomas, there remains an important subset of patients who remain refractory to conventional therapy. Treatment with chemotherapeutic agents such as hydroxyurea and alpha-interferon has provided minimal benefit. In this review, the role of newly emerging novel therapies for meningiomas, with a focus on targeted molecular agents, will be discussed.

Malignant gliomas: strategies to increase the effectiveness of targeted molecular treatment

Recently, there has been increasing interest in the use of targeted molecular agents for the treatment of malignant gliomas. These agents are generally well tolerated but have demonstrated only modest activity. In this article, the current status of targeted molecular agents for malignant gliomas will be reviewed and strategies to improve their effectiveness will be discussed.

Human breast tumor cells are more resistant to cardiac glycoside toxicity than non-tumorigenic breast cells

Cardiotonic steroids (CTS), specific inhibitors of Na,K-ATPase activity, have been widely used for treating cardiac insufficiency. Recent studies suggest that low levels of endogenous CTS do not inhibit Na,K-ATPase activity but play a role in regulating blood pressure, inducing cellular kinase activity, and promoting cell viability. Higher CTS concentrations inhibit Na,K-ATPase activity and can induce reactive oxygen species, growth arrest, and cell death. CTS are being considered as potential novel therapies in cancer treatment, as they have been shown to limit tumor cell growth. However, there is a lack of information on the relative toxicity of tumor cells and comparable non-tumor cells. We have investigated the effects of CTS compounds, ouabain, digitoxin, and bufalin, on cell growth and survival in cell lines exhibiting the full spectrum of non-cancerous to malignant phenotypes. We show that CTS inhibit membrane Na,K-ATPase activity equally well in all cell lines tested regardless of metastatic potential. In contrast, the cellular responses to the drugs are different in non-tumor and tumor cells. Ouabain causes greater inhibition of proliferation and more extensive apoptosis in non-tumor breast cells compared to malignant or oncogene-transfected cells. In tumor cells, the effects of ouabain are accompanied by activation of anti-apoptotic ERK1/2. However, ERK1/2 or Src inhibition does not sensitize tumor cells to CTS cytotoxicity, suggesting that other mechanisms provide protection to the tumor cells. Reduced CTS-sensitivity in breast tumor cells compared to non-tumor cells indicates that CTS are not good candidates as cancer therapies.

Role of C5b-9 complement complex and response gene to complement-32 (RGC-32) in cancer

Complement system activation plays an important role in both innate and acquired immunity, with the activation of complement and the subsequent formation of C5b-9 terminal complement complex on cell membranes inducing target cell death. Recognition of this role for C5b-9 leads to the assumption that C5b-9 might play an antitumor role. However, sublytic C5b-9 induces cell cycle progression by activating signal transduction pathways and transcription factors in cancer cells, indicating a role in tumor promotion for this complement complex. The induction of the cell cycle by C5b-9 is dependent upon the activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/FOXO1 and ERK1 pathways in a Gi protein-dependent manner. C5b-9 also induces response gene to complement (RGC)-32, a gene that plays a role in cell cycle promotion through activation of Akt and the CDC2 kinase. RGC-32 is expressed by tumor cells and plays a dual role in cancers, in that it has both a tumor suppressor role and tumor-promoting activity. Thus, through the activation of tumor cells, the C5b-9-mediated induction of the cell cycle plays an important role in tumor proliferation and oncogenesis.

mTOR is frequently active in GH-secreting pituitary adenomas without influencing their morphopathological features

Initiating factors and mechanisms of tumor formation are poorly understood in nonfamilial pituitary adenomas. Alteration of intracellular pathways is an underlying event in numerous neoplasms. Among them, excessive activation of mammalian target of rapamycin (mTOR) pathway and its two main regulators, Akt and Erk, has been detected frequently in solid tumors. This study tests the activation of mTOR pathway in pituitary adenomas and its influence on their morphopathological features. Fifty-three pituitary adenomas were fresh frozen after surgery and analyzed by western blotting using phospho-specific antibodies. The impact of Akt and Erk activation on mTOR pathway was assessed in five primary cultures derived from the excised adenomas using selective kinase inhibitors. Statistical correlations of size, volume, Ki-67 %, Knosp's grading, and somatostatin receptor (SSTR) expression with the activation of mentioned kinases was performed. GHomas showed the highest frequency (71 %) and level of mTOR pathway activity comparing to other adenomas (33 %). No significant correlation was found between mTOR activation and any of the morphopathological features in the studied samples. mTOR kinase phosphorylation was independent of Erk and Akt in primary cultures. Erk activity was significant in all types of adenomas but was the highest in control samples. Its phosphorylation correlated inversely with the Knosp's grading in nonfunctional pituitary adenomas and directly with somatostatin receptor subtype 2 A expression in GHomas. Presented data point to the noteworthy mTOR activity in GHomas. However, the lack of correlation with morphopathological features, its independence of Erk and Akt phosphorylation, and high level of Erk activity in control pituitary necessitate further research for clarifying the role of these pathways in pituitary adenomas.

Simulated evolution of signal transduction networks

Signal transduction is the process of routing information inside cells when receiving stimuli from their environment that modulate the behavior and function. In such biological processes, the receptors, after receiving the corresponding signals, activate a number of biomolecules which eventually transduce the signal to the nucleus. The main objective of our work is to develop a theoretical approach which will help to better understand the behavior of signal transduction networks due to changes in kinetic parameters and network topology. By using an evolutionary algorithm, we designed a mathematical model which performs basic signaling tasks similar to the signaling process of living cells. We use a simple dynamical model of signaling networks of interacting proteins and their complexes. We study the evolution of signaling networks described by mass-action kinetics. The fitness of the networks is determined by the number of signals detected out of a series of signals with varying strength. The mutations include changes in the reaction rate and network topology. We found that stronger interactions and addition of new nodes lead to improved evolved responses. The strength of the signal does not play any role in determining the response type. This model will help to understand the dynamic behavior of the proteins involved in signaling pathways. It will also help to understand the robustness of the kinetics of the output response upon changes in the rate of reactions and the topology of the network.

Use of pharmacokinetic/pharmacodynamic biomarkers to support rational cancer drug development

The process of drug development in oncology has struggled to alter at a pace in keeping with the rapid discovery and testing of agents that act on a wide variety of molecular targets. The rational development of such agents requires an understanding of drug effect(s) on their purported target. It is likely that testing these drugs in a framework designed to examine cytotoxic agents will fail to establish their full potential. We discuss how data gained from biomarker investigation might impact on drug development and provide examples that highlight the development, validation and use of pharmacokinetic, and especially pharmacodynamic biomarkers as drug development moves from the laboratory into clinical testing. The challenges of performing assays to satisfy regulatory requirements have been the subject of much debate. We recommend the implementation of appropriate, fit-for-purpose biomarkers in clinical trials of all new cancer drugs.

Intrinsic resistance to selumetinib, a selective inhibitor of MEK1/2, by cAMP-dependent protein kinase A activation in human lung and colorectal cancer cells

Background:

MEK is activated in ∼40% colorectal cancer (CRC) and 20–30% non-small cell lung cancer (NSCLC). Selumetinib is a selective inhibitor of MEK1/2, which is currently in clinical development.

Methods:

We evaluated the effects of selumetinib in vitro and in vivo in CRC and NSCLC cell lines to identify cancer cell characteristics correlating with sensitivity to MEK inhibition.

Results:

Five NSCLC and six CRC cell lines were treated with selumetinib and classified according to the median inhibitory concentration (IC₅₀) values as sensitive (⩽1 μℳ) or resistant (>1 μℳ). In selumetinib-sensitive cancer cell lines, selumetinib treatment induced G1 cell-cycle arrest and apoptosis and suppression of tumour growth as xenografts in immunodeficient mice. Evaluation of intracellular effector proteins and analysis of gene mutations showed no correlation with selumetinib sensitivity. Microarray gene expression profiles revealed that the activation of cAMP-dependent protein kinase A (PKA) was associated with MEK inhibitor resistance. Combined targeting of both MEK and PKA resulted in cancer cell growth inhibition of MEK inhibitor-resistant cancer cell lines in vitro and in vivo.

Conclusion:

This study provides molecular insights to explain resistance to an MEK inhibitor in human cancer cell lines.

The molecular pathogenesis of corticotroph tumours

BACKGROUND

The pathogenesis of tumour formation in the anterior pituitary including adrenocorticotropic hormone (ACTH)-secreting tumours has been intensively studied, but the causative mechanisms involved in pituitary cell transformation and tumourigenesis remain unclear.

MATERIALS AND METHODS

We searched PubMed on any paper related with molecular pathology of pituitary corticotroph adenomas and have included to this review all relevant references published up to June 2011.

RESULTS

Current studies increased our knowledge on the genetic basis of McCune-Albright syndrome (MAS), multiple endocrine neoplasia type 1 (MEN1), Carney complex (CNC), pituitary adenoma predisposition syndromes and tuberous sclerosis, but they have performed little to elucidate the causes of sporadic pituitary tumours including Cushing disease.

DISCUSSION

The aim of this review was to focus on the most recently published advances in the molecular pathology of corticotroph adenomas, which are presented in the context of changes seen in all types of pituitary adenomas, as well as in terms of corticotrophin-releasing hormone/ACTH/cortisol-specific pathways.

CONCLUSIONS

We would expect that over the next 5 years, more detailed analysis of inter-cellular communication pathways between pituitary cells, including the cadherins and integrins, and their interactions with other signalling pathways such as the β-catenin cascade will help elucidate what exactly goes awry in the formation of a benign corticotroph adenoma. This should in turn predict novel forms of pharmacological tumour control.

Dermatologic toxicities in epidermal growth factor receptor and multikinase inhibitors

Targeted therapies have produced significant treatment advances for patients diagnosed with a variety of tumor types. These therapies are associated with unique dermatologic toxicities that may hamper treatment efforts and cause significant discomfort for patients. Prevention and management of these toxicities can allow patients to remain on therapy and hence receive maximum clinical benefit from the drug.

Preclinical evaluation of injectable sirolimus formulated with polymeric nanoparticle for cancer therapy

Nanoparticles are useful delivery vehicles for promising drug candidates that face obstacles for clinical applicability. Sirolimus, an inhibitor of mammalian target of rapamycin has gained attention for targeted anticancer therapy, but its clinical application has been limited by its poor solubility. This study was designed to enhance the feasibility of sirolimus for human cancer treatment. Polymeric nanoparticle (PNP)–sirolimus was developed as an injectable formulation and has been characterized by transmission electron microscopy and dynamic light scattering. Pharmacokinetic analysis revealed that PNP–sirolimus has prolonged circulation in the blood. In addition, PNP–sirolimus preserved the in vitro killing effect of free sirolimus against cancer cells, and intravenous administration displayed its potent in vivo anticancer efficacy in xenograft tumor mice. In addition, PNP–sirolimus enhanced the radiotherapeutic efficacy of sirolimus both in vitro and in vivo. Clinical application of PNP–sirolimus is a promising strategy for human cancer treatment.

Combination Agents Versus Multi-Targeted Agents – Pros and Cons

Cancer, in all its various forms, is perhaps the archetypical multi-factorial disease and it is therefore not surprising that single-target drugs are rarely useful as anti-cancer agents when used on their own. Traditional cancer therapy has relied on effective drug combinations and the more recent emergence of compounds that simultaneously modulate multiple targets has added to the oncology armoury and raised the question as to which approach, drug combinations or single compound multi-targeted drug, is to be preferred. This chapter reviews the basis for combining existing drugs and how these combinations are selected, and compares these with multi-targeted drugs (MTDs) such as sunitinib, a broad-spectrum kinase inhibitor that inhibits a range of growth factors. Whether using physical combinations or MTDs, or indeed combinations of MTDs, the choice of which targets and which pathways to attack is crucial and the rationale for selecting these is discussed in detail. The NCI Cancer Therapy Evaluation Program, designed to facilitate trials of novel combinations, will aid in the rational selection of targets and pathways to combine in future MTDs. The pros and cons of combinations and MTDs in terms of the relative challenges in clinical development are examined, and the systematic use of biomarkers, better approaches to patient selection, and improved design of trials to take account of the heightened potential for acute and delayed on- and off-target toxicities are highlighted.