Synergistic combination of ritonavir and cisplatin as an efficacious therapy in human cervical cancer cells: a computational drug discovery and in vitro insight.

HIV-protease inhibitor Ritonavir (RTV) is a clinical-stage drug. We exhibit here the synergistic effect of RTV coupled with cisplatin as potential combination therapy for treatment of cervical cancer. Knowledge about the interaction of RTV with the high-expression signatures in cancer is limited. Therefore, we utilized computational techniques to understand and assess the drug-binding affinity and drug-target interaction of RTV with these altered protein signatures. Computational studies revealed the potential interaction ability of RTV along with few other HIV protease inhibitors against these altered cancer targets. All targets exhibited good affinity towards RTV and the highest affinity was exhibited by CYP450 3A4, PDGFR and ALK. RTV established stable interaction with PDGFR and molecular dynamics simulation confirms their frequent interaction for 300 ns. Control docking of PDGFR with standard PDGFR inhibitor exhibited lower binding affinity when compared with RTV-PDGFR complex. In search of drugs as a part of combination therapy to reduce side effects of Cisplatin, this paper further evaluated the effect of combination of RTV and Cisplatin in cervical cancer cells. We propose several combination models that combines anti-viral drug RTV and standard chemotherapeutic agent, Cisplatin to be synergistic with CI value ranging from of 0.01 to 1.14. These observations suggest that anti-viral compound (RTV) could act synergistically with Cisplatin for cervical cancer therapy. However, further studies are warranted to investigate the combinatorial mode of action of RTV and Cisplatin on different molecular pathways to have a translational outcome in cervical cancer.Communicated by Ramaswamy H. Sarma.

PPAR-γ Partial Agonists in Disease-Fate Decision with Special Reference to Cancer.

Peroxisome proliferator-activated receptor-γ (PPAR-γ) has emerged as one of the most extensively studied transcription factors since its discovery in 1990, highlighting its importance in the etiology and treatment of numerous diseases involving various types of cancer, type 2 diabetes mellitus, autoimmune, dermatological and cardiovascular disorders. Ligands are regarded as the key determinant for the tissue-specific activation of PPAR-γ. However, the mechanism governing this process is merely a contradictory debate which is yet to be systematically researched. Either these receptors get weakly activated by endogenous or natural ligands or leads to a direct over-activation process by synthetic ligands, serving as complete full agonists. Therefore, fine-tuning on the action of PPAR-γ and more subtle modulation can be a rewarding approach which might open new avenues for the treatment of several diseases. In the recent era, researchers have sought to develop safer partial PPAR-γ agonists in order to dodge the toxicity induced by full agonists, akin to a balanced activation. With a particular reference to cancer, this review concentrates on the therapeutic role of partial agonists, especially in cancer treatment. Additionally, a timely examination of their efficacy on various other disease-fate decisions has been also discussed.

Blockade of growth hormone receptor signaling by using pegvisomant: A functional therapeutic strategy in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is an aggressive neoplasm with poor clinical outcome because most patients present at an advanced stage, at which point curative surgical options, such as tumor excision or liver transplantation, are not feasible. Therefore, the majority of HCC patients require systemic therapy. Nonetheless, the currently approved systemic therapies have limited effects, particularly in patients with advanced and resistant disease. Hence, there is a critical need to identify new molecular targets and effective systemic therapies to improve HCC outcome. The liver is a major target of the growth hormone receptor (GHR) signaling, and accumulating evidence suggests that GHR signaling plays an important role in HCC pathogenesis. We tested the hypothesis that GHR could represent a potential therapeutic target in this aggressive neoplasm. We measured GH levels in 767 HCC patients and 200 healthy controls, and then carried out clinicopathological correlation analyses. Moreover, specific inhibition of GHR was performed in vitro using siRNA and pegvisomant (a small peptide that blocks GHR signaling and is currently approved by the FDA to treat acromegaly) and in vivo, also using pegvisomant. GH was significantly elevated in 49.5% of HCC patients, and these patients had a more aggressive disease and poorer clinical outcome (P<0.0001). Blockade of GHR signaling with siRNA or pegvisomant induced substantial inhibitory cellular effects in vitro. In addition, pegvisomant potentiated the effects of sorafenib (P<0.01) and overcame sorafenib resistance (P<0.0001) in vivo. Mechanistically, pegvisomant decreased the phosphorylation of GHR downstream survival proteins including JAK2, STAT3, STAT5, IRS-1, AKT, ERK, and IGF-IR. In two patients with advanced-stage HCC and high GH who developed sorafenib resistance, pegvisomant caused tumor stability. Our data show that GHR signaling represents a novel "druggable" target, and pegvisomant may function as an effective systemic therapy in HCC. Our findings could also lead to testing GHR inhibition in other aggressive cancers.

Disruption of Growth Hormone Receptor Signaling Abrogates Hepatocellular Carcinoma Development.

Introduction: Hepatocellular carcinoma (HCC) is the most common type of primary liver cancers. It is an aggressive neoplasm with dismal outcome because most of the patients present with an advanced-stage disease, which precludes curative surgical options. Therefore, these patients require systemic therapies that typically induce small improvements in overall survival. Hence, it is crucial to identify new and promising therapeutic targets for HCC to improve the current outcome. The liver is a key organ in the signaling cascade triggered by the growth hormone receptor (GHR). Previous studies have shown that GHR signaling stimulates the proliferation and regeneration of liver cells and tissues; however, a definitive role of GHR signaling in HCC pathogenesis has not been identified. Methods: In this study, we used a direct and specific approach to analyze the role of GHR in HCC development. This approach encompasses mice with global (Ghr-/- ) or liver-specific (LiGhr-/- ) disruption of GHR expression, and the injection of diethylnitrosamine (DEN) to develop HCC in these mice. Results: Our data show that DEN induced HCC in a substantial majority of the Ghr+/+ (93.5%) and Ghr +/- (87.1%) mice but not in the Ghr-/- (5.6%) mice (P < 0.0001). Although 57.7% of LiGhr-/- mice developed HCC after injection of DEN, these mice had significantly fewer tumors than LiGhr+/+ (P < 0.001), which implies that the expression of GHR in the liver cells might increase tumor burden. Notably, the pathologic, histologic, and biochemical characteristics of DEN-induced HCC in mice resembled to a great extent human HCC, despite the fact that etiologically this model does not mimic this cancer in humans. Our data also show that the effects of DEN on mice livers were primarily related to its carcinogenic effects and ability to induce HCC, with minimal effects related to toxic effects. Conclusion: Collectively, our data support an important role of GHR in HCC development, and suggest that exploiting GHR signaling may represent a promising approach to treat HCC.

Enhancing Antigen Retrieval to Unmask Signaling Phosphoproteins in Formalin-fixed Archival Tissues.

The introduction of targeted therapy has revolutionized cancer treatment. Nonetheless, for this approach to succeed, it is crucial to identify the targets, particularly when activated, in tumor tissues. Phosphorylation is a posttranslational modification that causes activation of numerous oncogenic protein kinases and transcription regulators. Hence, phosphoproteins is a class of biomarkers that has therapeutic and prognostic implications directly relevant to cancer patients' management. Despite the progress in histopathology methodology, analysis of the expression of phosphoproteins in tumor tissues still represents a challenge owing to preanalytical and analytical factors that include antigen retrieval strategies. In this study, we tested the hypothesis that optimizing antigen retrieval methods will improve phosphoproteins unmasking and enhance their immunohistochemical staining signal. We screened 4 antigen retrieval methods by using antibodies specific for 3 oncogenic phosphoproteins to stain human lymphoma tumors that were developed in severe combined immunodeficiency mice and subsequently fixed in formalin for 2 years. Then, we used antibodies specific for 15 survival phosphoproteins to compare the most effective method identified from our screening experiment to the antigen retrieval method that is most commonly utilized. Using the antigen retrieval buffer Tris-EDTA at pH 9.0 and heating for 45 minutes at 97°C unmasked and significantly enhanced the staining of 9 of the 15 phosphoproteins (P<0.0001). Our antigen retrieval approach is cost effective and feasible for clinical and research settings. We anticipate that combining this approach with the newly proposed methods to improve tissue fixation will further improve unmasking of phosphoproteins in human and animal tissues.

p38 MAP kinases: plausible diagnostic and prognostic serum protein marker of non small cell lung cancer.

INTRODUCTION: p38 MAPK signaling molecules plays a dual role in cancer, both progression and suppression. Elevated expression of p38α was reported in lung cancer tissue in rat model. Our objective was to explore the concentration of all 4 isoforms of p38MAPK in serum of Non Small Cell Lung Cancer (NSCLC). MATERIAL AND METHODS: The blood samples were collected from 77 NSCLC patients, 52 ethically matched healthy controls and 18 follow up patients were collected as some patients expired and some discontinued the treatment. The concentration of all isoforms of p38 (p38α, p38ß, p38γ, and p38δ) were evaluated by Surface Plasmon Resonance (SPR) technology. RESULT: The levels of all isoforms of serum p38 were significantly elevated at pre-therapy compare to control. Only p38α expression was significantly associated with tumor stage and its expression reduced after treatment which is then validated by western blot. However, no changes were observed in other isoforms after therapy. CONCLUSION: Our study revealed that, p38α is more efficient among all the isoform to predict the disease accurately and it can be concluded that p38 MAPK may be used as diagnostic as well as prognostic marker of NSCLC disease.

Diagnostic Significance of p38 Isoforms (p38α, p38ß, p38γ, p38δ) in Head and Neck Squamous Cell Carcinoma: Comparative Serum Level Evaluation and Design of Novel Peptide Inhibitor Targeting the Same.

PURPOSE: The p38 mitogen-activated protein kinase (MAPKs) play a crucial role in the production of pro-inflammatory cytokines and over-expression of it increase cytokines which promote cancer. Among four isoforms, p38α has been well studied in head and neck squamous cell carcinoma (HNSCC) and other cancers as a therapeutic target. p38δ has recently emerged as a potential disease-specific drug target. Elevated serum p38α level in HNSCC was reported earlier from our lab. This study aims to estimate the levels of p38 MAPK-isoforms in the serum of HNSCC and design peptide inhibitor targeting the same. MATERIALS AND METHODS: Levels of p38 MAPK isoforms in the serum of HNSCC and healthy controls were quantified by surface plasmon resonance technology. The peptide inhibitor for p38 MAPK was designed by molecular modeling using Grid-based Ligand Docking with Energetics tools and compared with known specific inhibitors. RESULTS: We have observed highly elevated levels of all four isoforms of p38 MAPK in serum of HNSCC patients compared to the control group. Further, serum p38α, p38ß, and p38δ levels were down regulated after therapy in follow-up patients, while p38γ showed no response to the therapy. Present study screened designed peptide WFYH as a specific inhibitor against p38δ. The specific inhibitor of p38δ was found to have no effect on p38α due to great structural difference at ATP binding pocket. CONCLUSION: In this study, first time estimated the levels of p38 MAPK isoforms in the serum of HNSCC. It can be concluded that p38 MAPK isoforms can be a diagnostic and prognostic marker for HNSCC and p38δ as a therapeutic target.

Structural insights of Mycobacterium GTPase-Obg and anti-sigma-F factor Usfx interaction.

An essential protein for bacterial growth, GTPase-Obg (Obg), is known to play an unknown but crucial role in stress response as its expression increases in Mycobacterium under stress conditions. It is well reported that Obg interacts with anti-sigma-F factor Usfx; however, a detailed analysis and structural characterization of their physical interaction remain undone. In view of above-mentioned points, this study was conceptualized for performing binding analysis and structural characterization of Obg-Usfx interaction. The binding studies were performed by surface plasmon resonance, while in silico docking analysis was done to identify crucial residues responsible for Obg-Usfx interaction. Surface plasmon resonance results clearly suggest that N-terminal and G domains of Obg mainly contribute to Usfx binding. Also, binding constants display strong affinity that was further evident by intermolecular hydrogen bonds and hydrophobic interactions in the predicted complex. Strong interaction between Obg and Usfx supports the view that Obg plays an important role in stress response, essentially required for Mycobacterium survival. As concluded by various studies that Obg is crucial for Mycobacterium survival under stress, this structural information may help us in designing novel and potential inhibitors against resistant Mycobacterium strains.

Quantification of Rac1 and Rac1b in serum of non small cell lung cancer by label free real time assay.

BACKGROUND: Rac proteins play a major role in tumorogenesis. We quantified Rac1 and Rac1b in serum of non small cell lung cancer (NSCLC) patients. METHODS: The blood of 77 NSCLC patients and 52 healthy controls were collected and quantified the concentration of Rac1 and Rac1b mainly by surface plasmon resonance and it was verify by Western blot analysis. RESULTS: Rac1 and Rac1b were found to be significantly over expressed in serum of NSCLC patients compare to healthy controls. The level of Rac proteins were found to be increased in all stages of cancer. Despite the low survival rate, we managed to collect serum sample of the 18 follow up patients after the therapy, where 11 patients' of CR+PR group showed down regulation of the Rac protein after chemotherapy and unfortunately 80% patients died during the study period. CONCLUSION: The high specificity and sensitivity obtained from ROC analysis for Rac1 and Rac1b envisaged it to be used as a serum diagnostic marker in the early stage of cancer.

NFκB-p50 as a blood based protein marker for early diagnosis and prognosis of head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSCC) is the major health concern in Indian population. Despite of advanced treatment the mortality rate for this disease has not been improved very much. Current research focused on development of protein marker for the diagnosis and prognosis of HNSCC. The case control study was performed with 125 HNSCC patients and 104 control cases. The level of p50 and IκBα proteins in serum were evaluated at pre and post therapy by label free real time surface plasmon resonance (SPR) and western blot analysis. The serum p50 concentration were significantly (P < 0.0001) higher at the time of diagnosis i.e. pre therapy (Mean ± SD = 27.06 ± 4.88 ng/µl) as compared to controls (Mean ± SD = 16.96 ± 4.04 ng/µl) while it decline at post therapy (Mean ± SD = 21.01 ± 4.98 ng/µl). Similarly, the concentration of IκBα protein in serum were slightly higher at pre therapy (Mean ± SD = 8.33 ± 1.85 ng/µl) as compared to controls (Mean ± SD = 7.27 ± 1.84 ng/µl) and declined at post therapy (Mean ± SD = 7.09 ± 1.24 ng/µl). The level of p50 was also high at the early stage of the disease. The specificity and sensitivity of p50 proteins obtained from ROC analysis revealed the potentiality to be diagnostic protein marker for HNSCC for its accuracy in the study cohort.

Identification of serum sirtuins as novel noninvasive protein markers for frailty.

Frailty has emerged as a major health issue among older patients. A consensus on definition and diagnosis is yet to be achieved. Various biochemical abnormalities have been reported in frailty. Activation of sirtuins, a conserved family of NAD-dependent proteins, is one of the many mimics of calorie restriction which improves lifespan and health in experimental animals. In this cross-sectional study, we assessed the circulating sirtuin levels in 119 (59.5%) nonfrail and 81 (40.5%) frail individuals, diagnosed by Fried's criteria. Serum SIRT1, SIRT2, and SIRT3 were estimated by surface plasmon resonance (SPR) and Western blot. Serum sirtuins level in mean+SD; SIRT1 (nonfrail -4.67 ± 0.48 ng/µL; frail - 3.72 ± 0.48 ng/µL; P < 0.0001), SIRT2 (nonfrail - 15.18 ± 2.94 ng/µL; frail - 14.19 ± 2.66 ng/µL; P = 0.016), and SIRT3 (nonfrail-7.72 ± 1.84 ng/µL; frail - 6.12 ± 0.97 ng/µL; P < 0.0001) levels were significantly lower among frail patients compared with the nonfrail. In multivariable regression analysis, lower sirtuins level were significantly associated with frailty after adjusting age, gender, diabetes mellitus, hypertension, cognitive status (Mini Mental State Examination scores) and number of comorbidities. For detecting the optimum diagnostic cutoff value a ROC analysis was carried out. The area under curve for SIRT1 was 0.9037 (cutoff - 4.29 ng/µL; sensitivity - 81.48%; specificity - 79.83%) and SIRT3 was 0.7988 (cutoff - 6.61 ng/µL; sensitivity - 70.37%; specificity - 70.59%). This study shows that lower circulating SIRT1 and SIRT3 levels can be distinctive marker of frailty.

Conformational plasticity of cryptolepain: accumulation of partially unfolded states in denaturants induced equilibrium unfolding.

pH and chemical denaturant dependent conformational changes of a serine protease cryptolepain from Cryptolepis buchanani are presented in this paper. Activity measurements, near UV, far UV CD, fluorescence emission spectroscopy, and ANS binding studies have been carried out to understand the folding mechanism of the protein in the presence of denaturants. pH and chemical denaturants have a marked effect on the stability, structure, and function of many globular proteins due to their ability to influence the electrostatic interactions. The preliminary biophysical study on cryptolepain shows that major elements of secondary structure are beta-sheets. Under neutral conditions the enzyme was stable in urea while GuHCl-induced equilibrium unfolding was cooperative. Cryptolepain shows little ANS binding even under neutral conditions due to more hydrophobicity of beta-sheets. Multiple intermediates were populated during the pH-induced unfolding of cryptolepain. Temperature-induced denaturation of cryptolepain in the molten globule like state is non-cooperative, contrary to the cooperativity seen with the native protein, suggesting the presence of two parts, possibly domains, in the molecular structure of cryptolepain, with different stability that unfolds in steps. Interestingly, the GuHCl-induced unfolding of A state (molten globule state) of cryptolepain is unique, as lower concentration of denaturant, not only induces structure but also facilitate transition from one molten globule like state (MG(1)) into another (MG(2)). The increase of pH drives the protein into alkaline denatured state characterized by the absence of any ANS binding. GuHCl- and urea-induced unfolding transition curves at pH 12.0 were non-coincidental indicating the presence of an intermediate in the unfolding pathway.