Summary
Background
Pazopanib is a multi-targeted tyrosine kinase inhibitor shown to be clinically active in the treatment of various cancer types. This study aimed to evaluate the maximum tolerated ...regimen (MTR), safety, and pharmacokinetics of pazopanib in combination with irinotecan and cetuximab in adult patients with relapsed or refractory metastatic colorectal cancer (mCRC).
Patients and methods
This was a Phase I, 3 + 3 design, open-label, dose-escalation study (NCT0050943; VEG108925) conducted in sequential cohorts to determine the MTR of pazopanib and irinotecan administered with cetuximab. Twenty-five patients received treatment in three dosing cohorts and were evaluated for safety and tolerability of the combination and pharmacokinetics of individual drugs.
Results
The MTR was determined to be 400 mg pazopanib per day orally in combination with 150 mg/m
2
irinotecan biweekly and 250 mg/m
2
cetuximab weekly by infusion. Neutropenia was the main dose-limiting toxicity. Pharmacokinetic results suggested that the overall systemic exposure to SN-38, the active metabolite of irinotecan, was affected by pazopanib to a greater extent than was the systemic exposure to irinotecan itself.
Conclusions
This study provided evidence for the manageable safety profile and feasibility of using the novel triplet combination of pazopanib, irinotecan, and cetuximab in patients with refractory mCRC. Further large-scale Phase II studies are warranted.
Cancers of diverse cell lineages express high levels of cyclin E, and in various studies, cyclin E overexpression correlates with increased tumor aggression. One way that normal control of cyclin E ...expression is disabled in cancer cells is via loss-of-function mutations sustained by FBXW7. This gene encodes the Fbw7 tumor suppressor protein that provides substrate specificity for a ubiquitin ligase complex that targets multiple oncoproteins for degradation. Numerous other mechanisms besides Fbw7 mutations can deregulate cyclin E expression and activity in cancer cells. Recent reports demonstrate that inappropriate cyclin E expression may have far-reaching biological consequences for cell physiology, including altering gene expression programs governing proliferation, differentiation, survival and senescence. In this review, we discuss the function of mammalian cyclin E in the context of these new data as well as the complex network that connects cyclin E functions to the cellular controls regulating its expression and activity.
Indoleamine 2,3‐dioxygenase 1 (IDO1) is a key enzyme associated with immunomodulation through its regulation of the tryptophan‐kynurenine (Kyn) pathway in advanced cancers, including metastatic renal ...cell carcinoma (mRCC). However, the failure of IDO1 inhibitors when used in combination with immune checkpoint inhibitors (ICIs), as observed in clinical trials, raises a number of questions. This study aimed to investigate the association of tryptophan 2,3‐dioxygenase (TDO) and IDO1 with cancer development and resistance to immunotherapy in patients with RCC. In our analysis of RCC tissue samples, tissue Kyn levels were elevated in advanced‐stage RCC and correlated well with TDO expression levels in RCC tumor cells. In patients with mRCC, TDO rather than IDO1 was expressed in RCC tumor cells, showing a strong association with Kyn expression. Furthermore, immunohistochemical staining of TDO was strongly associated with the staining intensity of forkhead box P3, as well as ICI therapy response and survival in patients with mRCC. Our study is the first to show that TDO expression in tumor tissues is associated with progression and survival, confirming its potential as a predictive biomarker of primary resistance to immunotherapy in patients with mRCC. Our findings suggest that strategies aimed at inhibiting TDO, rather than IDO1, in combination with ICI therapy may aid in the control of mRCC progression.
This study aimed to investigate the association of tryptophan 2,3‐dioxygenase (TDO) and indoleamine 2,3‐dioxygenase 1 (IDO1) with cancer development and resistance to immunotherapy in renal cell carcinoma (RCC) patients. Our results suggest that TDO expression in tumor cells is associated with kynurenine accumulation, progression, and survival, confirming its potential as a predictive biomarker of primary resistance to immunotherapy in RCC patients. We believe that our study makes a significant contribution to the literature because, to the best of our knowledge, it is the first to show that the accumulation of kynurenine induced by TDO in tumor tissues is associated with progression and survival. Further, we believe that this paper will be of interest to the readership of your journal because our results strongly recommend the testing of specific TDO inhibitors or dual inhibitors of IDO1 and TDO with ICI treatment in future preclinical and clinical trials focusing on mRCC.
Glioma-initiating cells (GICs), also called glioma stem cells, are responsible for tumor initiation, relapse, and therapeutic resistance. Here, we show that TGF-β inhibitors, currently under clinical ...development, target the GIC compartment in human glioblastoma (GBM) patients. Using patient-derived specimens, we have determined the gene responses to TGF-β inhibition, which include inhibitors of DNA-binding protein (Id)-1 and -3 transcription factors. We have identified a cell population enriched for GICs that expresses high levels of CD44 and Id1 and tend to be located in a perivascular niche. The inhibition of the TGF-β pathway decreases the CD44(high)/Id1(high) GIC population through the repression of Id1 and Id3 levels, therefore inhibiting the capacity of cells to initiate tumors. High CD44 and Id1 levels confer poor prognosis in GBM patients.
In this placebo-controlled trial, CSL830, a subcutaneous C1 inhibitor, significantly reduced the rate of hereditary angioedema attacks; local site reactions were the dominant side effect. Of the ...patients who received 60 IU per kilogram twice weekly, 40% had no attacks for 16 weeks.
Hereditary angioedema is a disabling and potentially fatal condition characterized by recurrent episodes of swelling without urticaria or pruritus. The condition is caused by deficiency (type I) or dysfunction (type II) of the C1 inhibitor protein.
1
Patients have insufficient C1 inhibitor function to prevent bradykinin production by the contact system, leading to episodes of increased capillary hyperpermeability and swelling. These episodes manifest clinically as angioedema attacks.
2
,
3
Low levels of C1 inhibitor protein antigen or low functional levels of C1 inhibitor activity, as well as low levels of complement C4, are diagnostic for hereditary angioedema, and baseline C1 inhibitor function . . .
Abstract
Cathepsin K is a cysteine protease member of the cathepsin lysosomal protease family. Although cathepsin K is highly expressed in osteoclasts, lower levels of cathepsin K are also found in a ...variety of other tissues. Secretion of cathepsin K from the osteoclast into the sealed osteoclast–bone cell interface results in efficient degradation of type I collagen. The absence of cathepsin K activity in humans results in pycnodysostosis, characterized by increased bone mineral density and fractures. Pharmacologic cathepsin K inhibition leads to continuous increases in bone mineral density for ≤5 years of treatment and improves bone strength at the spine and hip. Compared with other antiresorptive agents, cathepsin K inhibition is nearly equally efficacious for reducing biochemical markers of bone resorption but comparatively less active for reducing bone formation markers. Despite multiple efforts to develop cathepsin K inhibitors, potential concerns related to off-target effects of the inhibitors against other cathepsins and cathepsin K inhibition at nonbone sites, including skin and perhaps cardiovascular and cerebrovascular sites, prolonged the regulatory approval process. A large multinational randomized, double-blind phase III study of odanacatib in postmenopausal women with osteoporosis was recently completed. Although that study demonstrated clinically relevant reductions in fractures at multiple sites, odanacatib was ultimately withdrawn from the regulatory approval process after it was found to be associated with an increased risk of cerebrovascular accidents. Nonetheless, the underlying biology and clinical effects of cathepsin K inhibition remain of considerable interest and could guide future therapeutic approaches for osteoporosis.
There is a clear need for additional therapeutic options for the treatment of osteoporosis. This review summarizes the underlying biology and potential clinical utility of cathepsin K inhibitors.
Staphylococcus aureus produces hospital- and community-acquired infections, with methicillin-resistant S. aureus posing a serious public health threat. The golden carotenoid pigment of S. aureus, ...staphyloxanthin, promotes resistance to reactive oxygen species and host neutrophil-based killing, and early enzymatic steps in staphyloxanthin production resemble those for cholesterol biosynthesis. We determined the crystal structures of S. aureus dehydrosqualene synthase (CrtM) at 1.58 angstrom resolution, finding structural similarity to human squalene synthase (SQS). We screened nine SQS inhibitors and determined the structures of three, bound to CrtM. One, previously tested for cholesterol-lowering activity in humans, blocked staphyloxanthin biosynthesis in vitro (median inhibitory concentration ~100 nM), resulting in colorless bacteria with increased susceptibility to killing by human blood and to innate immune clearance in a mouse infection model. This finding represents proof of principle for a virulence factor-based therapy against S. aureus.
Cryptotanshinone (CPT) is a natural compound extracted from herbal medicine that has been previously shown to possess antitumor properties in various types of human cancer cells. In the present ...study, we examined the potential role of CPT in the treatment of colorectal cancer. Using SW480, HCT116, and LOVO colorectal cancer cell lines, the effects of CPT on cell viability, apoptosis, and tumorigenicity were evaluated. The results showed that CPT significantly inhibited the growth and viability of SW480, HCT116, and LOVO cell lines by inducing apoptosis and prevented anchorage dependent growth on agar. In addition, CPT inhibited the activation of Signal transducer and activator of transcription 3 (Stat3) pathways in colorectal cancer cells. Stat3 is a transcription factor that mediates the expression of various genes associated with many cellular processes, such as inflammation and cell growth, and has been shown to promote several cancer types, including colorectal cancer. These findings indicate that CPT may be a potential candidate for the treatment and prevention of colorectal cancer in part by inhibiting the activation of Stat3.
Targeting heparan sulfate proteoglycans (HSPGs) and enzymes involved in heparan sulfate (HS) chain editing is emerging as a new anticancer strategy. The involvement of HSPGs in tumor cell signaling, ...inflammation, angiogenesis and metastasis indicates that agents able to inhibit aberrant HSPG functions can potentially act as multitarget drugs affecting both tumor cell growth and the supportive boost provided by the microenvironment. Moreover, accumulating evidence supports that an altered expression or function of HSPGs, or of the complex enzyme system regulating their activities, can also depress the tumor response to anticancer treatments in several tumor types. Thereby, targeting HSPGs or HSPG modifying enzymes appears an appealing approach to enhance chemotherapy efficacy. A great deal of effort from academia and industry has led to the development of agents mimicking HS, and/or inhibiting HSPG modifying enzymes. Inhibitors of Sulf-2, an endosulfatase that edits the HS sulfation pattern, and inhibitors of heparanase, the endoglycosidase that produces functional HS fragments, appear particularly promising. In fact, a Sulf-2 inhibitor (OKN-007), and two heparanase inhibitors/HS mimics (roneparstat, PG545) are currently under early clinical investigation. In this review, we summarized preclinical studies in experimental tumor models of the main chemical classes of Sulf-2 and heparanase inhibitors. We described examples of different mechanisms through which heparanase and HSPGs, often in cooperation, may impact tumor sensitivity to various antitumor agents. Finally, we reported a few preclinical studies showing increased antitumor efficacy obtained with the use of candidate clinical HS mimics in combination regimens.
To further enhance the antitumor efficacy of DNA vaccine, we proposed a synergistic strategy that targeted tumor cells and angiogenesis simultaneously. In this study, a Semliki Forest Virus (SFV) ...replicon DNA vaccine expressing 1–4 domains of murine VEGFR2 and IL12 was constructed, and was named pSVK-VEGFR2-GFc-IL12 (CAVE). The expression of VEGFR2 antigen and IL12 adjuvant molecule in 293T cells in vitro were verified by western blot and enzyme-linked immune sorbent assay (ELISA). Then CAVE was co-immunized with CAVA, a SFV replicon DNA vaccine targeting survivin and β-hCG antigens constructed previously. The antitumor efficacy of our combined replicon vaccines was evaluated in mice model and the possible mechanism was further investigated. The combined vaccines could elicit efficient humoral and cellular immune responses against survivin, β-hCG and VEGFR2 simultaneously. Compared with CAVE or CAVA vaccine alone, the combined vaccines inhibited the tumor growth and improved the survival rate in B16 melanoma mice model more effectively. Furthermore, the intratumoral microvessel density was lowest in combined vaccines group than CAVE or CAVA alone group. Therefore, this synergistic strategy of DNA vaccines for tumor treatment results in an increased antitumor efficacy, and may be more suitable for translation to future research and clinic.
•We developed combined replicon vaccines that target tumor cells and angiogenesis simultaneously.•The combined vaccines exhibited an enhanced antitumor efficacy in B16 melanoma mice model.•The combined vaccines elicited efficient humoral and cellular immune responses against survivin, β-hCG and VEGFR2.•The anti-angiogenesis effect was also enhanced in mice immunized with combined vaccines.
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