Mallesh Pandrala
Senior Physical Research Scientist, Rad/Molecular Imaging Program at Stanford
All Publications
-
Inhibition of protein translational machinery in triple-negative breast cancer as a promising therapeutic strategy.
Cell reports. Medicine
2024: 101552
Abstract
Y-box binding protein-1 (YB-1) is a proto-oncogenic protein associated with protein translation regulation. It plays a crucial role in the development and progression of triple-negative breast cancer (TNBC). In this study, we describe a promising approach to inhibit YB-1 using SU056, a small-molecule inhibitor. SU056 physically interacts with YB-1 and reduces its expression, which helps to restrain the progression of TNBC. Proteome profiling analysis indicates that the inhibition of YB-1 by SU056 can alter the proteins that regulate protein translation, an essential process for cancer cell growth. Preclinical studies on human cells, mice, and patient-derived xenograft tumor models show the effectiveness of SU056. Moreover, toxicological studies have shown that SU056 treatment and dosing are well tolerated without any adverse effects. Overall, our study provides a strong foundation for the further development of SU056 as a potential treatment option for patients with TNBC by targeting YB-1.
View details for DOI 10.1016/j.xcrm.2024.101552
View details for PubMedID 38729158
-
PET Imaging of Innate Immune Activation Using 11C Radiotracers Targeting GPR84.
JACS Au
2023; 3 (12): 3297-3310
Abstract
Chronic innate immune activation is a key hallmark of many neurological diseases and is known to result in the upregulation of GPR84 in myeloid cells (macrophages, microglia, and monocytes). As such, GPR84 can potentially serve as a sensor of proinflammatory innate immune responses. To assess the utility of GPR84 as an imaging biomarker, we synthesized 11C-MGX-10S and 11C-MGX-11Svia carbon-11 alkylation for use as positron emission tomography (PET) tracers targeting this receptor. In vitro experiments demonstrated significantly higher binding of both radiotracers to hGPR84-HEK293 cells than that of parental control HEK293 cells. Co-incubation with the GPR84 antagonist GLPG1205 reduced the binding of both radiotracers by >90%, demonstrating their high specificity for GPR84 in vitro. In vivo assessment of each radiotracer via PET imaging of healthy mice illustrated the superior brain uptake and pharmacokinetics of 11C-MGX-10S compared to 11C-MGX-11S. Subsequent use of 11C-MGX-10S to image a well-established mouse model of systemic and neuro-inflammation revealed a high PET signal in affected tissues, including the brain, liver, lung, and spleen. In vivo specificity of 11C-MGX-10S for GPR84 was confirmed by the administration of GLPG1205 followed by radiotracer injection. When compared with 11C-DPA-713-an existing radiotracer used to image innate immune activation in clinical research studies-11C-MGX-10S has multiple advantages, including its higher binding signal in inflamed tissues in the CNS and periphery and low background signal in healthy saline-treated subjects. The pronounced uptake of 11C-MGX-10S during inflammation, its high specificity for GPR84, and suitable pharmacokinetics strongly support further investigation of 11C-MGX-10S for imaging GPR84-positive myeloid cells associated with innate immune activation in animal models of inflammatory diseases and human neuropathology.
View details for DOI 10.1021/jacsau.3c00435
View details for PubMedID 38155640
View details for PubMedCentralID PMC10751761
-
Carbon-11 Labelling of Benzenesulfonamide Analogues as Novel Radiotracers to Visualize the Pore-forming Activity of Perforin
ELSEVIER SCIENCE INC. 2023: S221
View details for Web of Science ID 001128725600293
-
Development and initial evaluation of a novel 11C-labeled PET tracer to image GPR84 expressing-myeloid cells during neuroinflammation
SOC NUCLEAR MEDICINE INC. 2023
View details for Web of Science ID 001109210200159
-
A New Nrf2 Inhibitor Enhances Chemotherapeutic Effects in Glioblastoma Cells Carrying p53 Mutations.
Cancers
2022; 14 (24)
Abstract
TP53 tumor suppressor gene is a commonly mutated gene in cancer. p53 mediated senescence is critical in preventing oncogenesis in normal cells. Since p53 is a transcription factor, mutations in its DNA binding domain result in the functional loss of p53-mediated cellular pathways. Similarly, nuclear factor erythroid 2-related factor 2 (Nrf2) is another transcription factor that maintains cellular homeostasis by regulating redox and detoxification mechanisms. In glioblastoma (GBM), Nrf2-mediated antioxidant activity is upregulated while p53-mediated senescence is lost, both rendering GBM cells resistant to treatment. To address this, we identified novel Nrf2 inhibitors from bioactive compounds using a molecular imaging biosensor-based screening approach. We further evaluated the identified compounds for their in vitro and in vivo chemotherapy enhancement capabilities in GBM cells carrying different p53 mutations. We thus identified an Nrf2 inhibitor that is effective in GBM cells carrying the p53 (R175H) mutation, a frequent clinically observed hotspot structural mutation responsible for chemotherapeutic resistance in GBM. Combining this drug with low-dose chemotherapies can potentially reduce their toxicity and increase their efficacy by transiently suppressing Nrf2-mediated detoxification function in GBM cells carrying this important p53 missense mutation.
View details for DOI 10.3390/cancers14246120
View details for PubMedID 36551609
-
Increased macrophage phagocytic activity with TLR9 agonist conjugation of an anti- Borrelia burgdorferi monoclonal antibody.
Clinical immunology (Orlando, Fla.)
2022: 109180
Abstract
Borrelia burgdorferi (Bb) infection causes Lyme disease, for which there is need for more effective therapies. Here, we sequenced the antibody repertoire of plasmablasts in Bb-infected humans. We expressed recombinant monoclonal antibodies (mAbs) representing the identified plasmablast clonal families, and identified their binding specificities. Our recombinant anti-Bb mAbs exhibit a range of activity in mediating macrophage phagocytosis of Bb. To determine if we could increase the macrophage phagocytosis-promoting activity of our anti-Bb mAbs, we generated a TLR9-agonist CpG-oligo-conjugated anti-BmpA mAb. We demonstrated that our CpG-conjugated anti-BmpA mAb exhibited increased peak Bb phagocytosis at 12-24 h, and sustained macrophage phagocytosis over 60+ hrs. Further, our CpG-conjugated anti-BmpA mAb induced macrophages to exhibit a sustained activation morphology. Our findings demonstrate the potential for TLR9-agonist CpG-oligo conjugates to enhance mAb-mediated clearance of Bb, and this approach might also enhance the activity of other anti-microbial mAbs.
View details for DOI 10.1016/j.clim.2022.109180
View details for PubMedID 36396013
-
Designing Novel BCR-ABL Inhibitors for Chronic Myeloid Leukemia with Improved Cardiac Safety.
Journal of medicinal chemistry
2022
Abstract
Development of tyrosine kinase inhibitors (TKIs) targeting the BCR-ABL oncogene constitutes an effective approach for the treatment of chronic myeloid leukemia (CML) and/or acute lymphoblastic leukemia. However, currently available inhibitors are limited by drug resistance and toxicity. Ponatinib, a third-generation inhibitor, has demonstrated excellent efficacy against both wild type and mutant BCR-ABL kinase, including the "gatekeeper" T315I mutation that is resistant to all other currently available TKIs. However, it is one of the most cardiotoxic of the FDA-approved TKIs. Herein, we report the structure-guided design of a novel series of potent BCR-ABL inhibitors, particularly for the T315I mutation. Our drug design paradigm was coupled to iPSC-cardiomyocyte models. Systematic structure-activity relationship studies identified two compounds, 33a and 36a, that significantly inhibit the kinase activity of both native BCR-ABL and the T315I mutant. We have identified the most cardiac-safe TKIs reported to date, and they may be used to effectively treat CML patients with the T315I mutation.
View details for DOI 10.1021/acs.jmedchem.1c01853
View details for PubMedID 35944901
-
Reengineering Ponatinib to Minimize Cardiovascular Toxicity
CANCER RESEARCH
2022; 82 (15): 2777-2791
View details for DOI 10.1158/0008-5472.CAN-21-365
View details for Web of Science ID 000835635300001
-
Inhibition of triple negative breast cancer metastasis via Enolase-1 modulation
AMER ASSOC CANCER RESEARCH. 2022
View details for Web of Science ID 000892509505480
-
Reengineering Ponatinib to Minimize Cardiovascular Toxicity.
Cancer research
2022
Abstract
Small molecule Tyrosine Kinase Inhibitors (TKIs) have revolutionized cancer treatment and greatly improved patient survival. However, life-threatening cardiotoxicity of many TKIs has become a major concern. Ponatinib (ICLUSIG) was developed as an inhibitor of the BCR-ABL oncogene and is among the most cardiotoxic of TKIs. Consequently, use of ponatinib is restricted to the treatment of tumors carrying T315I-mutated BCR-ABL, which occurs in chronic myeloid leukemia (CML) and confers resistance to first- and second-generation inhibitors such as imatinib and nilotinib. Through parallel screening of cardiovascular toxicity and anti-tumor efficacy assays, we engineered safer analogs of ponatinib that retained potency against T315I BCR-ABL kinase activity and suppressed T315I mutant CML tumor growth. The new compounds were substantially less toxic in human cardiac vasculogenesis and cardiomyocyte contractility assays in vitro. The compounds showed a larger therapeutic window in vivo, leading to regression of human T315I mutant CML xenografts without cardiotoxicity. Comparison of the kinase inhibition profiles of ponatinib and the new compounds suggested that ponatinib cardiotoxicity is mediated by a few kinases, some of which were previously unassociated with cardiovascular disease. Overall, the study develops an approach using complex phenotypic assays to reduce the high risk of cardiovascular toxicity that is prevalent among small molecule oncology therapeutics.
View details for DOI 10.1158/0008-5472.CAN-21-3652
View details for PubMedID 35763671
-
SU086, an inhibitor of HSP90, impairs glycolysis and represents a treatment strategy for advanced prostate cancer.
Cell reports. Medicine
2022; 3 (2): 100502
Abstract
Among men, prostate cancer is the second leading cause of cancer-associated mortality, with advanced disease remaining a major clinical challenge. We describe a small molecule, SU086, as a therapeutic strategy for advanced prostate cancer. We demonstrate that SU086 inhibits the growth of prostate cancer cells invitro, cell-line and patient-derived xenografts invivo, and exvivo prostate cancer patient specimens. Furthermore, SU086 in combination with standard of care second-generation anti-androgen therapies displays increased impairment of prostate cancer cell and tumor growth invitro and invivo. Cellular thermal shift assay reveals that SU086 binds to heat shock protein 90 (HSP90) and leads to a decrease in HSP90 levels. Proteomic profiling demonstrates that SU086 binds to and decreases HSP90. Metabolomic profiling reveals that SU086 leads to perturbation of glycolysis. Our study identifies SU086 as a treatment for advanced prostate cancer as a single agent or when combined with second-generation anti-androgens.
View details for DOI 10.1016/j.xcrm.2021.100502
View details for PubMedID 35243415
-
New Selective Inhibitors of ERG Positive Prostate Cancer: ERGi-USU-6 Salt Derivatives.
ACS medicinal chemistry letters
2021; 12 (11): 1703-1709
Abstract
Prostate cancer is among the leading causes of cancer related death of men in the United States. The ERG gene fusion leading to overexpression of near full-length ERG transcript and protein represents most prevalent (50-65%) prostate cancer driver gene alterations. The ERG oncoprotein overexpression persists in approximately 35% of metastatic castration resistant prostate cancers. Due to the emergence of eventual refractoriness to second- and third-generation androgen axis-based inhibitors, there remains a pressing need to develop drugs targeting other validated prostate cancer drivers such as ERG. Here we report the new and more potent ERG inhibitor ERGi-USU-6 developed by structure-activity studies from the parental ERGi-USU. We have developed an improved procedure for the synthesis of ERGi-USU-6 and identified a salt formulation that further improves its activity in biological assays for selective targeting of ERG harboring prostate cancer cells.
View details for DOI 10.1021/acsmedchemlett.1c00308
View details for PubMedID 34790292
-
Polypyridyl iridium(III) based catalysts for highly chemoselective hydrogenation of aldehydes
JOURNAL OF CATALYSIS
2019; 378: 283–88
View details for DOI 10.1016/j.jcat.2019.08.025
View details for Web of Science ID 000494887100032
-
Novel CMKLR1 Inhibitors for Application in Demyelinating Disease
SCIENTIFIC REPORTS
2019; 9
View details for DOI 10.1038/s41598-019-43428-8
View details for Web of Science ID 000467538500058
-
Iridium(III) polypyridyl based new catalysts for highly chemoselective hydrogenation of adehydes
AMER CHEMICAL SOC. 2019
View details for Web of Science ID 000478861202079
-
Novel CMKLR1 Inhibitors for Application in Demyelinating Disease.
Scientific reports
2019; 9 (1): 7178
Abstract
Small molecules that disrupt leukocyte trafficking have proven effective in treating patients with multiple sclerosis (MS). We previously reported that chemerin receptor chemokine-like receptor 1 (CMKLR1) is required for maximal clinical and histological experimental autoimmune encephalomyelitis (EAE); and identified CMKLR1 small molecule antagonist 2-(α-naphthoyl) ethyltrimethylammonium iodide (α-NETA) that significantly suppressed disease onset in vivo. Here we directly compared α-NETA versus FDA-approved MS drug Tecfidera for clinical efficacy in EAE; characterized key safety/toxicity parameters for α-NETA; identified structure-activity relationships among α-NETA domains and CMKLR1 inhibition; and evaluated improved α-NETA analogs for in vivo efficacy. α-NETA proved safe and superior to Tecfidera in suppressing clinical EAE. In addition, we discovered structurally differentiated α-NETA analogs (primarily ortho- or para-methoxy substitutions) with significantly improved target potency in vitro and improved efficacy in vivo. These findings suggest that α-NETA-based CMKLR1 inhibitors may prove safe and effective in treating demyelinating diseases and potentially other autoimmune disorders.
View details for PubMedID 31073181
-
Quantitative Proteomic Profiling Reveals Key Pathways in the Anticancer Action of Methoxychalcone Derivatives in Triple Negative Breast Cancer
JOURNAL OF PROTEOME RESEARCH
2018; 17 (10): 3574–85
View details for DOI 10.1021/acs.jproteome.8b00636
View details for Web of Science ID 000447118300023
-
Quantitative Proteomic Profiling Reveals Key Pathways in the Anticancer Action of Methoxychalcone Derivatives in Triple Negative Breast Cancer.
Journal of proteome research
2018
Abstract
Triple negative breast cancer is an aggressive, heterogeneous disease with high recurrence and metastasis rates even with modern chemotherapy regimens and thus is in need of new therapeutics. Here, three novel synthetic analogues of chalcones, plant-based molecules that have demonstrated potency against a wide variety of cancers, were investigated as potential therapeutics for triple negative breast cancer. These compounds exhibit IC50 values of 5 muM in triple negative breast cancer cell lines and are more potent against triple negative breast cancer cell lines than against nontumor breast cell lines according to viability experiments. Tandem mass tag-based quantitative proteomics followed by gene set enrichment analysis and validation experiments using flow cytometry, apoptosis, and Western blot assays revealed three different anticancer mechanisms for these compounds. First, the chalcone analogues induce the unfolded protein response followed by apoptosis. Second, increases in the abundances of MHC-I pathway proteins occurs, which would likely result in immune stimulation in an organism. And third, treatment with the chalcone analogues causes disruption of the cell cycle by interfering with microtubule structure and by inducing G1 phase arrest. These data demonstrate the potential of these novel chalcone derivatives as treatments for triple negative breast cancer, though further work evaluating their efficacy in vivo is needed.
View details for PubMedID 30200768
-
Design of deferasirox peptide-conjugated ligands for a selective delivery of anticancer Ti(IV) compounds
AMER CHEMICAL SOC. 2018
View details for Web of Science ID 000447609101274
-
Novel chalcone derivatives as potential therapeutic agents for triple negative breast cancer
AMER CHEMICAL SOC. 2018
View details for Web of Science ID 000447609102077
-
Small molecules facilitating DNA repair in breast cancer cells
AMER CHEMICAL SOC. 2018
View details for Web of Science ID 000447609102076
-
Inhibiting guanylate binding protein 1 (GBP1) impedes ovarian cancer progression
AMER ASSOC CANCER RESEARCH. 2018
View details for DOI 10.1158/1538-7445.AM2018-4951
View details for Web of Science ID 000468819503561
-
Studies to understand Ti(iV) speciation and transport in the human body
AMER CHEMICAL SOC. 2018
View details for Web of Science ID 000435539903188
-
A ubiquitous metal, difficult to track: towards an understanding of the regulation of titanium(IV) in humans
METALLOMICS
2017; 9 (4): 346–56
Abstract
Despite the ubiquitous nature of titanium(iv) and several examples of its beneficial behavior in different organisms, the metal remains underappreciated in biology. There is little understanding of how the metal might play an important function in the human body. Nonetheless, a new insight is obtained regarding the molecular mechanisms that regulate the blood speciation of the metal to maintain it in a nontoxic and potentially bioavailable form for use in the body. This review surveys the literature on Ti(iv) application in prosthetics and in the development of anticancer therapeutics to gain an insight into soluble Ti(iv) influx in the body and its long-term impact. The limitation in analytical tools makes it difficult to depict the full picture of how Ti(iv) is transported and distributed throughout the body. An improved understanding of Ti function and its interaction with biomolecules will be helpful in developing future technologies for its imaging in the body.
View details for DOI 10.1039/c6mt00223d
View details for Web of Science ID 000399771300002
View details for PubMedID 28164202
View details for PubMedCentralID PMC5397357
-
Differential Anticancer Activities of the Geometric Isomers of Dinuclear Iridium(III) Complexes
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
2015: 5694–5701
View details for DOI 10.1002/ejic.201501069
View details for Web of Science ID 000366432200015
-
Chlorido-containing ruthenium(II) and iridium(III) complexes as antimicrobial agents
DALTON TRANSACTIONS
2013; 42 (13): 4686–94
Abstract
A series of polypyridyl-ruthenium(II) and -iridium(III) complexes that contain labile chlorido ligands, [{M(tpy)Cl}(2){μ-bb(n)}](2/4+) {Cl-Mbb(n); where M = Ru or Ir; tpy = 2,2':6',2''-terpyridine; and bb(n) = bis[4(4'-methyl-2,2'-bipyridyl)]-1,n-alkane (n = 7, 12 or 16)} have been synthesised and their potential as antimicrobial agents examined. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the series of metal complexes against four strains of bacteria - Gram positive Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA), and Gram negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) - have been determined. All the ruthenium complexes were highly active and bactericidal. In particular, the Cl-Rubb(12) complex showed excellent activity against all bacterial cell lines with MIC values of 1 μg mL(-1) against the Gram positive bacteria and 2 and 8 μg mL(-1) against E. coli and P. aeruginosa, respectively. The corresponding iridium(III) complexes also showed significant antimicrobial activity in terms of MIC values; however and surprisingly, the iridium complexes were bacteriostatic rather than bactericidal. The inert iridium(III) complex, [{Ir(phen)(2)}(2){μ-bb(12)}](6+) {where phen = 1,10-phenanthroline) exhibited no antimicrobial activity, suggesting that it could not cross the bacterial membrane. The mononuclear model complex, [Ir(tpy)(Me(2)bpy)Cl]Cl(2) (where Me(2)bpy = 4,4'-dimethyl-2,2'-bipyridine), was found to aquate very rapidly, with the pK(a) of the iridium-bound water in the corresponding aqua complex determined to be 6.0. This suggests the dinuclear complexes [Ir(tpy)Cl}(2){μ-bb(n)}](4+) aquate and deprotonate rapidly and enter the bacterial cells as 4+ charged hydroxo species.
View details for DOI 10.1039/c3dt32775b
View details for Web of Science ID 000316294400045
View details for PubMedID 23360972
-
Iridium(III) Complexes Containing 1,10-Phenanthroline and Derivatives: Synthetic, Stereochemical, and Structural Studies, and their Antimicrobial Activity
AUSTRALIAN JOURNAL OF CHEMISTRY
2013; 66 (9): 1065–73
View details for DOI 10.1071/CH13264
View details for Web of Science ID 000324210400010