Adaptive protein and phosphoprotein networks which promote therapeutic sensitivity or acquired resistance

2014 ◽  
Vol 42 (4) ◽  
pp. 758-764 ◽  
Author(s):  
John Haley ◽  
Forest M. White

Despite the emergence of dozens of oncogenic targets and corresponding molecularly targeted therapies, in most cases tumours continue to progress or recur due to therapeutic resistance. In the present review, we highlight the ability of MS-based phosphoproteomics to quantify oncogenic signalling networks driving tumour growth and invasion, as well as those networks enabling tumour cell survival in the presence of chemotherapeutics. Quantitative protein phosphorylation profiling will facilitate the design and development of optimal therapeutic strategies targeting the initial tumour while simultaneously blocking the predominant resistance mechanisms.

2020 ◽  
Vol 4 (1) ◽  
pp. 315-330
Author(s):  
Vito W. Rebecca ◽  
Meenhard Herlyn

Resistance to targeted and immune-based therapies limits cures in patients with metastatic melanoma. A growing number of reports have identified nongenetic primary resistance mechanisms including intrinsic microenvironment- and lineage plasticity–mediated processes serving critical functions in the persistence of disease throughout therapy. There is a temporally shifting spectrum of cellular identities fluidly occupied by therapy-persisting melanoma cells responsible for driving therapeutic resistance and metastasis. The key epigenetic, metabolic, and phenotypic reprogramming events requisite for the manifestation and maintenance of so-called persister melanoma populations remain poorly understood and underscore the need to comprehensively investigate actionable vulnerabilities. Here we attempt to integrate the field's observations on nongenetic mechanisms of drug resistance in melanoma. We postulate that the future design of therapeutic strategies specifically addressing therapy-persisting subpopulations of melanoma will improve the curative potential of therapy for patients with metastatic disease.


2014 ◽  
Vol 369 (1638) ◽  
pp. 20130108 ◽  
Author(s):  
Florian Lang ◽  
Christos Stournaras

Ion transport across the cell membrane mediated by channels and carriers participate in the regulation of tumour cell survival, death and motility. Moreover, the altered regulation of channels and carriers is part of neoplastic transformation. Experimental modification of channel and transporter activity impacts tumour cell survival, proliferation, malignant progression, invasive behaviour or therapy resistance of tumour cells. A wide variety of distinct Ca 2+ permeable channels, K + channels, Na + channels and anion channels have been implicated in tumour growth and metastasis. Further experimental information is, however, needed to define the specific role of individual channel isoforms critically important for malignancy. Compelling experimental evidence supports the assumption that the pharmacological inhibition of ion channels or their regulators may be attractive targets to counteract tumour growth, prevent metastasis and overcome therapy resistance of tumour cells. This short review discusses the role of Ca 2+ permeable channels, K + channels, Na + channels and anion channels in tumour growth and metastasis and the therapeutic potential of respective inhibitors.


2006 ◽  
Vol 13 (Supplement_1) ◽  
pp. S89-S97 ◽  
Author(s):  
Iain R Hutcheson ◽  
Janice M Knowlden ◽  
Helen E Jones ◽  
Rajpal S Burmi ◽  
Richard A McClelland ◽  
...  

Aberrant epidermal growth factor receptor (EGFR) signalling, a key feature of a variety of human malignancies, can drive a range of mechanisms underlying tumour growth and progression, including increased cell proliferation, angiogenesis, metastasis and decreased apoptosis. Anti-EGFR therapies, as monotherapies and in combination with chemotherapy, have proved effective in inhibiting these processes both in the clinical and in the preclinical settings. However, only a small cohort of patients have derived significant benefit from this therapy, with both de novo and acquired resistance to these agents evident in a number of recent studies. If we are to improve the effectiveness of such targeted therapies, then there is an urgent need to understand the resistance mechanisms. Here, we describe both non-genomic and genomic mechanisms of resistance to the selective EGFR tyrosine kinase inhibitor gefitinib (IRESSA), which we have identified initially in an EGFR-positive tamoxifen-resistant MCF-7 breast cancer cell line, but more recently in other EGFR-positive cancer types. Importantly, we show that gefitinib, in common with anti-hormonal agents, is not a passive bystander in the cellular response to drug treatment, but plays an active role in promoting signalling pathways that serve to limit its anti-tumour activity and maintain the cellular cohort from which acquired resistance can ultimately evolve. These findings indicate that inductive signalling is an important determinant of response to EGFR-targeted therapies and deciphering such pathways may provide us with the opportunity to design more effective strategies to combat resistance mechanisms and improve response to initial therapy.


2011 ◽  
Vol 32 (1) ◽  
pp. 91-104 ◽  
Author(s):  
Anjani Kumar ◽  
Naveen Kumar Vishvakarma ◽  
Abhishek Tyagi ◽  
Alok Chandra Bharti ◽  
Sukh Mahendra Singh

The present study explores the potential of the anti-neoplastic action of aspirin in a transplantable murine tumour model of a spontaneously originated T-cell lymphoma designated as Dalton's lymphoma. The antitumour action of aspirin administered to tumour-bearing mice through oral and/or intraperitoneal (intratumoral) routes was measured via estimation of survival of tumour-bearing mice, tumour cell viability, tumour progression and changes in the tumour microenvironment. Intratumour administration of aspirin examined to assess its therapeutic potential resulted in retardation of tumour progression in tumour-bearing mice. Oral administration of aspirin to mice as a prophylactic measure prior to tumour transplantation further primed the anti-neoplastic action of aspirin administered at the tumour site. The anti-neoplastic action of aspirin was associated with a decline in tumour cell survival, augmented induction of apoptosis and nuclear shrinkage. Tumour cells of aspirin-treated mice were found arrested in G0/G1 phase of the cell cycle and showed nuclear localization of cyclin B1. Intratumoral administration of aspirin was accompanied by alterations in the biophysical, biochemical and immunological composition of the tumour microenvironment with respect to pH, level of dissolved O2, glucose, lactate, nitric oxide, IFNγ (interferon γ), IL-4 (interleukin-4), IL-6 and IL-10, whereas the TGF-β (tumour growth factor-β) level was unaltered. Tumour cells obtained from aspirin-treated tumour-bearing mice demonstrated an altered expression of pH regulators monocarboxylate transporter-1 and V-ATPase along with alteration in the level of cell survival regulatory molecules such as survivin, vascular endothelial growth factor, heat-shock protein 70, glucose transporter-1, SOCS-5 (suppressor of cytokine signalling-5), HIF-1α (hypoxia-inducible factor-1α) and PUMA (p53 up-regulated modulator of apoptosis). The study demonstrates a possible indirect involvement of the tumour microenvironment in addition to a direct but limited anti-neoplastic action of aspirin in the retardation of tumour growth.


Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 318
Author(s):  
Valentina Angerilli ◽  
Francesca Galuppini ◽  
Gianluca Businello ◽  
Luca Dal Santo ◽  
Edoardo Savarino ◽  
...  

The advent of precision therapies against specific gene alterations characterizing different neoplasms is revolutionizing the oncology field, opening novel treatment scenarios. However, the onset of resistance mechanisms put in place by the tumor is increasingly emerging, making the use of these drugs ineffective over time. Therefore, the search for indicators that can monitor the development of resistance mechanisms and above all ways to overcome it, is increasingly important. In this scenario, microRNAs are ideal candidate biomarkers, being crucial post-transcriptional regulators of gene expression with a well-known role in mediating mechanisms of drug resistance. Moreover, as microRNAs are stable molecules, easily detectable in tissues and biofluids, they are the ideal candidate biomarker to identify patients with primary resistance to a specific targeted therapy and those who have developed acquired resistance. The aim of this review is to summarize the major studies that have investigated the role of microRNAs as mediators of resistance to targeted therapies currently in use in gastro-intestinal neoplasms, namely anti-EGFR, anti-HER2 and anti-VEGF antibodies, small-molecule tyrosine kinase inhibitors and immune checkpoint inhibitors. For every microRNA and microRNA signature analyzed, the putative mechanisms underlying drug resistance were outlined and the potential to be translated in clinical practice was evaluated.


2021 ◽  
Author(s):  
Pallavi M Gosavi ◽  
Kevin C Ngan ◽  
Megan Yeo ◽  
Cindy Su ◽  
Jiaming Li ◽  
...  

Targeted protein degradation (TPD) holds immense promise for drug discovery but mechanisms of acquired resistance to degraders remain to be fully identified. Here we used CRISPR-suppressor scanning to identify mechanistic classes of drug resistance mutations to molecular glue degraders in GSPT1 and RBM39, neosubstrates targeted by E3 ligase substrate receptors cereblon and DCAF15, respectively. While many mutations directly alter the ternary complex heterodimerization surface, distal resistance sites were also identified. Several distal mutations in RBM39 led to modest decreases in degradation yet can enable cell survival, underscoring how small differences in degradation can lead to resistance. Integrative analysis of resistance sites across GSPT1 and RBM39 revealed varying levels of sequence conservation and mutational constraint that control the emergence of different resistance mechanisms, highlighting that many regions co-opted by TPD are inessential. Altogether, our study identifies common resistance mechanisms for molecular glue degraders and outlines a general approach to survey neosubstrate requirements necessary for effective degradation.


2007 ◽  
Vol 30 (4) ◽  
pp. 97 ◽  
Author(s):  
A Wolf ◽  
J Mukherjee ◽  
A Guha

Introduction: GBMs are resistant to apoptosis induced by the hypoxic microenvironment and standard therapies including radiation and chemotherapy. We postulate that the Warburg effect, a preferential glycolytic phenotype of tumor cells even under aerobic conditions, plays a role in these aberrant pro-survival signals. In this study we quantitatively examined the expression profile of hypoxia-related glycolytic genes within pathologically- and MRI-defined “centre” and “periphery” of GBMs. We hypothesize that expression of hypoxia-induced glycolytic genes, particularly hexokinase 2 (HK2), favours cell survival and modulates resistance to tumour cell apoptosis by inhibiting the intrinsic mitochondrial apoptotic pathway. Methods: GBM patients underwent conventional T1-weighted contrast-enhanced MRI and MR spectroscopy studies on a 3.0T GE scanner, prior to stereotactic sampling (formalin and frozen) from regions which were T1-Gad enhancing (“centre”) and T2-positive, T1-Gad negative (“periphery”). Real-time qRT-PCR was performed to quantify regional gene expression of glycolytic genes including HK2. In vitro functional studies were performed in U87 and U373 GBM cell lines grown in normoxic (21% pO2) and hypoxic (< 1%pO2) conditions, transfected with HK2 siRNA followed by measurement of cell proliferation (BrdU), apoptosis (activated caspase 3/7, TUNEL, cytochrome c release) and viability (MTS assay). Results: There exists a differential expression profile of glycolytic enzymes between the hypoxic center and relatively normoxic periphery of GBMs. Under hypoxic conditions, there is increased expression of HK2 at the mitochondrial membrane in GBM cells. In vitro HK2 knockdown led to decreased cell survival and increased apoptosis via the intrinsic mitochondrial pathway, as seen by increased mitochondrial release of cytochrome-C. Conclusions: Increased expression of HK2 in the centre of GBMs promotes cell survival and confers resistance to apoptosis, as confirmed by in vitro studies. In vivo intracranial xenograft studies with injection of HK2-shRNA are currently being performed. HK2 and possibly other glycolytic enzymes may provide a target for enhanced therapeutic responsiveness thereby improving prognosis of patients with GBMs.


Cancers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 6
Author(s):  
Silvia La Monica ◽  
Claudia Fumarola ◽  
Daniele Cretella ◽  
Mara Bonelli ◽  
Roberta Minari ◽  
...  

Abemaciclib is an inhibitor of cyclin-dependent kinases (CDK) 4 and 6 that inhibits the transition from the G1 to the S phase of the cell cycle by blocking downstream CDK4/6-mediated phosphorylation of Rb. The effects of abemaciclib alone or combined with the third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib were examined in a panel of PC9 and HCC827 osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines carrying EGFR-dependent or -independent mechanisms of intrinsic or acquired resistance. Differently from sensitive cells, all the resistant cell lines analyzed maintained p-Rb, which may be considered as a biomarker of osimertinib resistance and a potential target for therapeutic intervention. In these models, abemaciclib inhibited cell growth, spheroid formation, colony formation, and induced senescence, and its efficacy was not enhanced in the presence of osimertinib. Interestingly, in osimertinib sensitive PC9, PC9T790M, and H1975 cells the combination of abemaciclib with osimertinib significantly inhibited the onset of resistance in long-term experiments. Our findings provide a preclinical support for using abemaciclib to treat resistance in EGFR mutated NSCLC patients progressed to osimertinib either as single treatment or combined with osimertinib, and suggest the combination of osimertinib with abemaciclib as a potential approach to prevent or delay osimertinib resistance in first-line treatment.


Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 663
Author(s):  
Yu Yuan ◽  
Abdalla Adam ◽  
Chen Zhao ◽  
Honglei Chen

Release of immunoreactive negative regulatory factors such as immune checkpoint limits antitumor responses. PD-L1 as a significant immunosuppressive factor has been involved in resistance to therapies such as chemotherapy and target therapy in various cancers. Via interacting with PD-1, PD-L1 can regulate other factors or lead to immune evasion of cancer cells. Besides, immune checkpoint blockade targeting PD-1/PD-L1 has promising therapeutic efficacy in the different tumors, but a significant percentage of patients cannot benefit from this therapy due to primary and acquired resistance during treatment. In this review, we described the utility of PD-L1 expression levels for predicting poor prognosis in some tumors and present evidence for a role of PD-L1 in resistance to therapies through PD-1/PD-L1 pathway and other correlating signaling pathways. Afterwards, we elaborate the key mechanisms underlying resistance to PD-1/PD-L1 blockade in cancer immunotherapy. Furthermore, promising combination of therapeutic strategies for patients resistant to PD-1/PD-L1 blockade therapy or other therapies associated with PD-L1 expression was also summarized.


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