Rash to the mTOR inhibitor everolimus: systematic review and meta-analysis

Mechanisms of Resistance to PI3K Inhibitors in Cancer: Adaptive Responses, Drug Tolerance and Cellular Plasticity

The phosphatidylinositol-3-kinase (PI3K) pathway plays a central role in the regulation of several signalling cascades which regulate biological processes such as cellular growth, survival, proliferation, motility and angiogenesis. The hyperactivation of this pathway is linked to tumour progression and is one of the most common events in human cancers. Additionally, aberrant activation of the PI3K pathway has been demonstrated to limit the effectiveness of a number of anti-tumour agents paving the way for the development and implementation of PI3K inhibitors in the clinic. However, the overall effectiveness of these compounds has been greatly limited by inadequate target engagement due to reactivation of the pathway by compensatory mechanisms. Herein, we review the common adaptive responses that lead to reactivation of the PI3K pathway, therapy resistance and potential strategies to overcome these mechanisms of resistance. Furthermore, we highlight the potential role in changes in cellular plasticity and PI3K inhibitor resistance.

Novel Targeted Therapies for Metastatic Thyroid Cancer-A Comprehensive Review

The knowledge on thyroid cancer biology has grown over the past decade. Thus, diagnostic and therapeutic strategies to manage thyroid cancer are rapidly evolving. With new insights into tumor biology and cancer genetics, several novel therapies have been approved for the treatment of thyroid cancer. Tyrosine kinase inhibitors (TKIs), such as lenvatinib and sorafenib, have been successfully utilized for the treatment of radioactive iodine (RAI)-refractory metastatic differentiated thyroid cancer (DTC). In addition, pretreatment with mitogen-activated protein kinase (MAPK) inhibitors (trametinib and selumetinib) has been shown to restore RAI avidity in previously RAI-refractory DTCs. Local therapies, such as external beam radiation and radiofrequency/ethanol ablation, have also been employed for treatment of DTC. Vandetanib and cabozantinib are the two TKIs currently approved by the Food and Drug Administration (FDA) for the treatment of medullary thyroid cancer (MTC). Other novel therapies, such as peptide receptor radionuclide therapy and carcinoembryonic antigen (CEA) vaccine, have also been utilized in treating MTC. Ongoing trials on selective rearranged-during-transfection (RET) protooncogene inhibitors, such as LOXO-292 and BLU-667, have demonstrated promising results in the treatment of metastatic MTC resistant to non-selective TKIs. The FDA-approved BRAF/MEK inhibitor combination of dabrafenib and trametinib has revolutionized treatment of BRAFV600E mutation positive anaplastic thyroid cancer. Several other emerging classes of medications, such as gene fusion inhibitors and immune checkpoint inhibitors, are being actively investigated in several clinical trials. In this review, we describe the molecular landscape of thyroid cancer and novel targeted therapies and treatment combinations available for the treatment of metastatic thyroid cancer.

Everolimus in the treatment of neuroendocrine tumors: efficacy, side-effects, resistance, and factors affecting its place in the treatment sequence

Since the initial approval of everolimus in 2011, there have been a number of important changes in therapeutic/diagnostic modalities as well as classification/staging systems of neuroendocrine tumors (NETs), which can significantly impact the use of everolimus in patients with advanced NETs. Areas covered: The efficacy of everolimus monotherapy and combination therapy demonstrated in clinical studies involving patients with advanced NETs are reviewed. Several factors affecting everolimus use are described including: the development and routine use of NET classification/staging systems; widespread use of molecular imaging modalities; side effects; drug resistance; and the availability of other treatment options. Furthermore, the current position of everolimus in the treatment approach is discussed, taking into account the recommendations from the recent guidelines. Expert opinion: Although everolimus demonstrated its high efficacy and tolerability in the RADIANT trials and other clinical studies, there still remain a number of controversies related to everolimus treatment in the management of NETs. The synergistic anti-growth effect of other agents in combination with everolimus or its effect on overall survival have not been established. The appropriate order of the use of everolimus in the treatment of advanced NETs still remains unclear, which needs to be defined in further studies and will be addressed in the new guidelines.

Accurate prediction and elucidation of drug resistance based on the robust and reproducible chemoresponse communities

Selecting the available treatment for each cancer patient from genomic context is a core goal of precision medicine, but innovative approaches with mechanism interpretation and improved performance are still highly needed. Through utilizing in vitro chemotherapy response data coupled with gene and miRNA expression profiles, we applied a network-based approach that identified markers not as individual molecules but as functional groups extracted from the integrated transcription factor and miRNA regulatory network. Based on the identified chemoresponse communities, the predictors of drug resistance achieved high accuracy in cross-validation and were more robust and reproducible than conventional single-molecule markers. Meanwhile, as candidate communities not only enriched abundant cellular process but also covered a variety of drug enzymes, transporters, and targets, these resulting chemoresponse communities furnished novel models to interpret multiple kinds of potential regulatory mechanism, such as dysregulation of cancer cell apoptosis or disturbance of drug metabolism. Moreover, compounds were linked based on the enrichment of their common chemoresponse communities to uncover undetected response patterns and possible multidrug resistance phenotype. Finally, an omnibus repository named ChemoCommunity (http://www.jianglab.cn/ChemoCommunity/) was constructed, which furnished a user-friendly interface for a convenient retrieval of the detailed information on chemoresponse communities. Taken together, our method, and the accompanying database, improved the performance of classifiers for drug resistance and provided novel model to uncover the possible regulatory mechanism of individual response to drug.

Low expression of PinX1 is associated with malignant behavior in basal-like breast cancer

Human Pinx1 protein, associated with shelterin proteins, is widely revealed as a haploinsufficient tumor suppressor. Growing evidence has manifested the deregulation of PinX1 in distinct cancers. Nonetheless, the loss status of PinX1 and its diagnostic, prognostic and clinicopathological significance in Basal-like breast cancer are still unclear. In the present study, the PinX1 expression levels of breast cancer tissues were investigated by qRT-PCR and immunoblotting assays. Then immunohistochemistry (IHC) was performed to detect PinX1 expression on a tissue microarray. The optimal threshold for PinX1 positivity was determined by receiver operating characteristic (ROC) curve analysis. To clarify the probable role of PinX1 in BLBC, the PinX1 knockout and stably over-expressed MDA-MB-231 cell lines were constructed by the CRISPR-Cas9 system and gene transfection. The association of PinX1 expression with cell proliferation, migration and apoptosis of MDA-MB-231 cells were observed by CCK-8 assay, wound healing assay, Transwell assay, flow cytometric analysis and immunoblotting of the cleaved caspase-3 protein level. Our results showed that both PinX1 mRNA and protein expression were downregulated in breast cancer tissues (P<0.05). In IHC analysis, the optimal cut-off parameter for PinX1 positive expression was 62.5% (the AUC was 0.749, P<0.01). PinX1 positivity was 76.9% (10/14) in luminal subtypes, 50% (5/10) in Her2-enriched breast cancer and 27.3% (9/33) in basal-like subtypes. Besides, in 59 invasive ductal breast carcinomas, PinX1 expression was inversely related to histology grade (P<0.05) while it was positively associated with PR status (P<0.05) and ER status (P<0.05). These results indicated that low expression of PinX1 correlated with aggressive clinicopathological significance of breast cancer, especially in the basal-like subtype. Besides, we identified that overexpression of PinX1 inhibited the proliferation rates and migration ability and increased the apoptosis rates of BLBC. Our findings demonstrated that low expression of PinX1 was associated with malignant behaviors in basal-like subtype of breast cancer. PinX1 is likely a feasible biomarker and molecular target of BLBC.

Palmar-plantar erythrodysesthesia: An uncommon adverse effect of everolimus

Mammalian target of rapamycin inhibitor everolimus is a novel agent used in endocrine therapy resistant hormone receptor positive metastatic breast cancer. Its use has been associated with clinically significant improvement in the otherwise dismal outcomes of this subset of patients. Rash is a common adverse effect associated with everolimus. However, Hand-foot syndrome is an uncommon toxicity with the use of this drug. We report a case of Grade 3 hand-foot syndrome following institution of everolimus therapy and describe its successful management.

The mTORC1 inhibitor everolimus has antitumor activity in vitro and produces tumor responses in patients with relapsed T-cell lymphoma

Everolimus is an oral agent that targets the mammalian target of rapamycin (mTOR) pathway. This study investigated mTOR pathway activation in T-cell lymphoma (TCL) cell lines and assessed antitumor activity in patients with relapsed/refractory TCL in a phase 2 trial. The mTOR pathway was activated in all 6 TCL cell lines tested and everolimus strongly inhibited malignant T-cell proliferation with minimal cytotoxic effects. Everolimus completely inhibited phosphorylation of ribosomal S6, a raptor/mTOR complex 1 (mTORC1) target, without a compensatory activation of the rictor/mTORC2 target Akt (S475). In the clinical trial, 16 patients with relapsed TCL were enrolled and received everolimus 10 mg by mouth daily. Seven patients (44%) had cutaneous (all mycosis fungoides); 4 (25%) had peripheral T cell not otherwise specified; 2 (13%) had anaplastic large cell; and 1 each had extranodal natural killer/T cell, angioimmunoblastic, and precursor T-lymphoblastic leukemia/lymphoma types. The overall response rate was 44% (7/16; 95% confidence interval [CI]: 20% to 70%). The median progression-free survival was 4.1 months (95% CI, 1.5-6.5) and the median overall survival was 10.2 months (95% CI, 2.6-44.3). The median duration of response for the 7 responders was 8.5 months (95% CI, 1.0 to not reached). These studies indicate that everolimus has antitumor activity and provide proof-of-concept that targeting the mTORC1 pathway in TCL is clinically relevant. This trial was registered at www.clinicaltrials.gov as #NCT00436618.

Side effects of targeted therapies: rash

OBJECTIVES

To present a thorough literature review on the assessment, grading, and treatment of rash associated with targeted therapies for cancer treatment. To identify ways that nursing can impact a patient's treatment experience by understanding and properly managing treatment for the rash.

DATA SOURCES

Peer-reviewed journal articles, textbooks.

CONCLUSION

Identification and management of rash induced by targeted therapies may improve quality of life and allow patients to continue drug therapy for their cancer to offer best outcomes.

IMPLICATIONS FOR NURSING PRACTICE

Nurses are in a unique position to assess, grade, and manage rash in patients receiving targeted therapies. Nurses will often be the first point of contact for the patient experiencing a rash, and the proper triage and advice on management can help the patient tolerate these drugs and enable them to remain on treatment.

Translation factors and ribosomal proteins control tumor onset and progression: how?

Gene expression is shaped by translational control. The modalities and the extent by which translation factors modify gene expression have revealed therapeutic scenarios. For instance, eukaryotic initiation factor (eIF)4E activity is controlled by the signaling cascade of growth factors, and drives tumorigenesis by favoring the translation of specific mRNAs. Highly specific drugs target the activity of eIF4E. Indeed, the antitumor action of mTOR complex 1 (mTORc1) blockers like rapamycin relies on their capability to inhibit eIF4E assembly into functional eIF4F complexes. eIF4E biology, from its inception to recent pharmacological targeting, is proof-of-principle that translational control is druggable. The case for eIF4E is not isolated. The translational machinery is involved in the biology of cancer through many other mechanisms. First, untranslated sequences on mRNAs as well as noncoding RNAs regulate the translational efficiency of mRNAs that are central for tumor progression. Second, other initiation factors like eIF6 show a tumorigenic potential by acting downstream of oncogenic pathways. Third, genetic alterations in components of the translational apparatus underlie an entire class of inherited syndromes known as 'ribosomopathies' that are associated with increased cancer risk. Taken together, data suggest that in spite of their evolutionary conservation and ubiquitous nature, variations in the activity and levels of ribosomal proteins and translation factors generate highly specific effects. Beside, as the structures and biochemical activities of several noncoding RNAs and initiation factors are known, these factors may be amenable to rational pharmacological targeting. The future is to design highly specific drugs targeting the translational apparatus.

The combination of RAD001 and MK-2206 exerts synergistic cytotoxic effects against PTEN mutant gastric cancer cells: involvement of MAPK-dependent autophagic, but not apoptotic cell death pathway

In the current study, we showed that the combination of mammalian target of rapamycin (mTOR) inhibitor RAD001 (everolimus) and Akt inhibitor MK-2206 exerted synergistic cytotoxic effects against low-phosphatase and tensin homolog (PTEN) gastric cancer cells (HGC-27 and SNU-601 lines). In HGC-27 cells, RAD001 and MK-2206 synergistically induced G1/S cell cycle arrest, growth inhibition, cell death but not apoptosis. RAD001 and MK-2206 synergistically induced light chain 3B (LC3B) and beclin-1 expression, two important autophagy indicators. Meanwhile, the autophagy inhibitor 3-methyladenine (3-MA) and chloroquine inhibited the cytotoxic effects by RAD001 and MK-2206, suggesting that autophagic, but not apoptotic cell death was important for the cytotoxic effects by the co-administration. We observed that the combination of RAD001 and MK-2206 exerted enhanced effects on Akt/mTOR inhibition, cyclin D1 down-regulation and ERK/MAPK(extracellular signal-regulated kinase/mitogen-activated protein kinases) activation. Intriguingly, MEK/ERK inhibitors PD98059 and U0126 suppressed RAD001 plus MK-2206-induced beclin-1 expression, autophagy induction and cytotoxicity in HGC-27 cells. In conclusion, these results suggested that the synergistic anti-gastric cancer cells ability by RAD001 and MK-2206 involves ERK-dependent autophagic cell death pathway.

Cap dependent translation contributes to resistance of myeloma cells to bortezomib

Multiple myeloma (MM) is the second most predominant blood malignancy. Proteasome inhibitors like bortezomib have increased life expectancy, but eventually patients develop resistance to therapy. It was proposed that bortezomib acts through the induction of the Unfolded Protein Response (UPR), i.e., accumulation of misfolded proteins causing a lethal stress response. By this theory, increasing the proteasome load by the stimulation of translation may worsen the UPR. Here we evaluated the crosstalk between translation and bortezomib toxicity in both bortezomib sensitive and resistant cells. We found that bortezomib toxicity does not correlate with induction of proapoptotic eIF2α phosphorylation, but rather caused a late reduction in initiation of translation. This effect was accompanied by dephosphorylation of the mTORC1 target 4E-BP1. Infection of myeloma cells with constitutively dephosphorylated 4E-BP1, worsened bortezomib induced cell death. Since mTORC1 inhibitors cause pharmacological inhibition of 4E-BP1 phosphorylation, we tested whether they could act synergistically with bortezomib. We found that both rapamycin, a specific mTORC1 blocker, and PP242 a mTOR antagonist induce the arrest of myeloma cells irrespective of bortezomib sensitivity. Sensitivity to mTOR inhibitors has been associated to the levels of eIF4E/4E-BPs. We found that levels of eIF4E and 4E-BPs are variable among patients, and that 15% of myeloma patients have increased levels of 4E-BP1/2. Primary cells of myeloma retain sensitivity to mTOR inhibition, when plated on stromal cells. We propose that translational load does not contribute to bortezomib-induced death, but rather mTOR targeting may be successful in bortezomib resistant patients, stratified for eIF4E/4EBPs.

Everolimus: side effect profile and management of toxicities in breast cancer

Everolimus is an orally available inhibitor of the mammalian target of rapamycin (mTOR), which has been approved in combination with exemestane for hormone receptor-positive (HR) breast cancer after failure of treatment with non-steroidal aromatase inhibitors. Everolimus is generally very well tolerated with most common side effects including stomatitis, rash, fatigue, hyperglycemia, hyperlipidemia, and myelosuppression. Most of these side effects are mild and resolve with dose interruptions or dose reductions. Symptomatic non-infectious pneumonitis is a relatively uncommon class effect of mTOR inhibitors, which can be life threatening. Given the efficacy of everolimus in HR-positive metastatic breast cancer, it is crucial for physicians to recognize toxicities related to everolimus and start timely interventions. This review will focus on the adverse events reported with everolimus in breast cancer trials and will provide practical guidelines for the management of these adverse events.