Astemizole Sensitizes Adrenocortical Carcinoma Cells to Doxorubicin by Inhibiting Patched Drug Efflux Activity

Bioelectric pharmacology of cancer: A systematic review of ion channel drugs affecting the cancer phenotype

Cancer is a pernicious and pressing medical problem; moreover, it is a failure of multicellular morphogenesis that sheds much light on evolutionary developmental biology. Numerous classes of pharmacological agents have been considered as cancer therapeutics and evaluated as potential carcinogenic agents; however, these are spread throughout the primary literature. Here, we briefly review recent work on ion channel drugs as promising anti-cancer treatments and present a systematic review of the known cancer-relevant effects of 109 drugs targeting ion channels. The roles of ion channels in cancer are consistent with the importance of bioelectrical parameters in cell regulation and with the functions of bioelectric signaling in morphogenetic signals that act as cancer suppressors. We find that compounds that are well-known for having targets in the nervous system, such as voltage-gated ion channels, ligand-gated ion channels, proton pumps, and gap junctions are especially relevant to cancer. Our review suggests further opportunities for the repurposing of numerous promising candidates in the field of cancer electroceuticals.

Nuclear size rectification: A potential new therapeutic approach to reduce metastasis in cancer

Research on metastasis has recently regained considerable interest with the hope that single cell technologies might reveal the most critical changes that support tumor spread. However, it is possible that part of the answer has been visible through the microscope for close to 200 years. Changes in nuclear size characteristically occur in many cancer types when the cells metastasize. This was initially discarded as contributing to the metastatic spread because, depending on tumor types, both increases and decreases in nuclear size could correlate with increased metastasis. However, recent work on nuclear mechanics and the connectivity between chromatin, the nucleoskeleton, and the cytoskeleton indicate that changes in this connectivity can have profound impacts on cell mobility and invasiveness. Critically, a recent study found that reversing tumor type-dependent nuclear size changes correlated with reduced cell migration and invasion. Accordingly, it seems appropriate to now revisit possible contributory roles of nuclear size changes to metastasis.

Loratadine, an antihistaminic drug, suppresses the proliferation of endometrial stromal cells by inhibition of TRPV2

The transient receptor potential (TRP) channel TRPV2 is widely expressed in a variety of different cell types and tissues. However, elucidating the exact biological functions of TRPV2 is significantly hampered by the lack of selective pharmacological tools to modulate channel activity in vitro and in vivo. This study aimed to identify new compounds that modify TRPV2 activity via the use of a plate-based calcium imaging approach to screen a drug repurposing library. Three antihistaminic drugs, loratadine, astemizole and clemizole were identified to reduce calcium-influx evoked by the TRPV2 agonist tetrahydrocannabivarin in HEK293 cells expressing murine TRPV2. Using single-cell calcium-microfluorimetry and whole-cell patch clamp recordings, we further confirmed that all three compounds induced a concentration-dependent block of TRPV2-mediated Ca²⁺ influx and whole-cell currents, with loratadine being the most potent antagonist of TRPV2. Moreover, this study demonstrated that loratadine was able to block both the human and mouse TRPV2 orthologs, without inhibiting the activity of other closely related members of the TRPV superfamily. Finally, loratadine inhibited TRPV2-dependent responses in a primary culture of mouse endometrial stromal cells and attenuated cell proliferation and migration in in vitro cell proliferation and wound healing assays. Taken together, our study revealed that the antihistaminic drugs loratadine, astemizole and clemizole target TRPV2 in a concentration-dependent manner. The identification of these antihistaminic drugs as blockers of TRPV2 may form a new starting point for the synthesis of more potent and selective TRPV2 antagonists, which could further lead to the unravelling of the physiological role of the channel.

Persistent Properties of a Subpopulation of Cancer Cells Overexpressing the Hedgehog Receptor Patched

Despite the development of new therapeutic strategies, cancer remains one of the leading causes of mortality worldwide. One of the current major challenges is the resistance of cancers to chemotherapy treatments inducing metastases and relapse of the tumor. The Hedgehog receptor Patched (Ptch1) is overexpressed in many types of cancers. We showed that Ptch1 contributes to the efflux of doxorubicin and plays an important role in the resistance to chemotherapy in adrenocortical carcinoma (ACC), a rare cancer which presents strong resistance to the standard of care chemotherapy treatment. In the present study, we isolated and characterized a subpopulation of the ACC cell line H295R in which Ptch1 is overexpressed and more present at the cell surface. This cell subpopulation is more resistant to doxorubicin, grows as spheroids, and has a greater capability of clonogenicity, migration, and invasion than the parental cells. Xenograft experiments performed in mice and in ovo showed that this cell subpopulation is more tumorigenic and metastatic than the parental cells. These results suggest that this cell subpopulation has cancer stem-like or persistent cell properties which were strengthened by RNA-seq. If present in tumors from ACC patients, these cells could be responsible for therapy resistance, relapse, and metastases.

Chemical Interrogation of Nuclear Size Identifies Compounds with Cancer Cell Line-Specific Effects on Migration and Invasion

Background: Lower survival rates for many cancer types correlate with changes in nuclear size/scaling in a tumor-type/tissue-specific manner. Hypothesizing that such changes might confer an advantage to tumor cells, we aimed at the identification of commercially available compounds to guide further mechanistic studies. We therefore screened for Food and Drug Administration (FDA)/European Medicines Agency (EMA)-approved compounds that reverse the direction of characteristic tumor nuclear size changes in PC3, HCT116, and H1299 cell lines reflecting, respectively, prostate adenocarcinoma, colonic adenocarcinoma, and small-cell squamous lung cancer. Results: We found distinct, largely nonoverlapping sets of compounds that rectify nuclear size changes for each tumor cell line. Several classes of compounds including, e.g., serotonin uptake inhibitors, cyclo-oxygenase inhibitors, β-adrenergic receptor agonists, and Na⁺/K⁺ ATPase inhibitors, displayed coherent nuclear size phenotypes focused on a particular cell line or across cell lines and treatment conditions. Several compounds from classes far afield from current chemotherapy regimens were also identified. Seven nuclear size-rectifying compounds selected for further investigation all inhibited cell migration and/or invasion. Conclusions: Our study provides (a) proof of concept that nuclear size might be a valuable target to reduce cell migration/invasion in cancer treatment and (b) the most thorough collection of tool compounds to date reversing nuclear size changes specific to individual cancer-type cell lines. Although these compounds still need to be tested in primary cancer cells, the cell line-specific nuclear size and migration/invasion responses to particular drug classes suggest that cancer type-specific nuclear size rectifiers may help reduce metastatic spread.

Methiothepin Increases Chemotherapy Efficacy against Resistant Melanoma Cells

We previously reported that methiothepin, a small molecule known as a nonselective serotonin 5-HT receptor antagonist, inhibited the doxorubicin efflux activity of the Hedgehog receptor Ptch1 and enhanced the cytotoxic, pro-apoptotic, anti-proliferative, and anti-clonogenic effects of doxorubicin on adrenocortical carcinoma cells. Here, we show that methiothepin also inhibits doxorubicin efflux and increases doxorubicin cytotoxicity in melanoma cells which endogenously overexpress Ptch1. Melanoma patients having the BRAF^V600E mutation are treated with vemurafenib, an inhibitor of BRAF^V600E, often in combination with trametinib, an inhibitor of MEK. Almost all patients ultimately acquire resistance to the treatment leading to disease progression. Here, we report that methiothepin overcomes the resistance of BRAF^V600E melanoma cells by enhancing the cytotoxicity of vemurafenib and trametinib on these cells leading to melanoma cells death. We observe that the addition of methiothepin to vemurafenib prevents migration of resistant melanoma cells more efficiently than vemurafenib alone. Our results provide an additional proof that Ptch1 drug efflux inhibition increases the effectiveness of anti-cancer treatments and overcomes resistance of melanoma cells expressing Ptch1.

The Role of Biomarkers in Adrenocortical Carcinoma: A Review of Current Evidence and Future Perspectives

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy arising from the adrenal cortex often with unexpected biological behavior. It can occur at any age, with two peaks of incidence: in the first and between fifth and seventh decades of life. Although ACC are mostly hormonally active, precursors and metabolites, rather than end products of steroidogenesis are produced by dedifferentiated and immature malignant cells. Distinguishing the etiology of adrenal mass, between benign adenomas, which are quite frequent in general population, and malignant carcinomas with dismal prognosis is often unfeasible. Even after pathohistological analysis, diagnosis of adrenocortical carcinomas is not always straightforward and represents a great challenge for experienced and multidisciplinary expert teams. No single imaging method, hormonal work-up or immunohistochemical labelling can definitively prove the diagnosis of ACC. Over several decades' great efforts have been made in finding novel reliable and available diagnostic and prognostic factors including steroid metabolome profiling or target gene identification. Despite these achievements, the 5-year mortality rate still accounts for approximately 75% to 90%, ACC is frequently diagnosed in advanced stages and therapeutic options are unfortunately limited. Therefore, imperative is to identify new biological markers that can predict patient prognosis and provide new therapeutic options.