AR and PI3K/AKT in Prostate Cancer: A Tale of Two Interconnected Pathways.

Prostate cancer (PCa) is the most common cancer in men. The androgen receptor (AR) has a pivotal role in the pathogenesis and progression of PCa. Many therapies targeting AR signaling have been developed over the years. AR signaling inhibitors (ARSIs), including androgen synthesis inhibitors and AR antagonists, have proven to be effective in castration-sensitive PCa (CSPC) and improve survival, but men with castration-resistant PCa (CRPC) continue to have a poor prognosis. Despite a good initial response, drug resistance develops in almost all patients with metastatic CRPC, and ARSIs are no longer effective. Several mechanisms confer resistance to ARSI and include AR mutations but also hyperactivation of other pathways, such as PI3K/AKT/mTOR. This pathway controls key cellular processes, including proliferation and tumor progression, and it is the most frequently deregulated pathway in human cancers. A significant interaction between AR and the PI3K/AKT/mTOR signaling pathway has been shown in PCa. This review centers on the current scene of different AR and PI3K signaling pathway inhibitors, either as monotherapy or in combination treatments in PCa, and the treatment outcomes involved in both preclinical and clinical trials. A PubMed-based literature search was conducted up to November 2022. The most relevant and recent articles were selected to provide essential information and current evidence on the crosstalk between AR and the PI3K signaling pathways. The ClinicalTrials.gov registry was used to report information about clinical studies and their results using the Advanced research tool, filtering for disease and target.

Tissue Expression of Androgen Receptor Splice Variant 7 at Radical Prostatectomy Predicts Risk of Progression in Untreated Nonmetastatic Prostate Cancer.

BACKGROUND: Androgen receptor splice variant V7 (AR-V7) was recently detected in circulating tumor cells of castration-resistant prostate cancer (PC) patients and its expression correlated with resistance to new-generation androgen signaling inhibitors. OBJECTIVES: We retrospectively analyzed whether AR-V7 expression was detectable on radical prostatectomy (RP) specimens of untreated nonmetastatic PC cases, and whether it could be associated with progression after surgery. METHOD: The expression of AR-V7 and AR-FL (full length) was separately evaluated by immunohistochemistry using a streptavidin-biotin-peroxidase system with 2 anti-AR-V7 and anti-AR-FL rabbit monoclonal antibodies. RESULTS: 56 PC cases, classified by their clinical risk, were analyzed. Positive expression was found in 24/32 cases in the high-risk group, 4/13 in the intermediate-risk group, and only 2/11 in the low-risk group. We found a significant correlation between AR-V7 positivity and both risk classification (p < 0.001) and progression after surgery (p < 0.001). CONCLUSIONS: In our population of untreated nonmetastatic PC, AR-V7 is detectable by immunohistochemistry in more than 50% of cases. At this early stage, AR-V7 positivity is associated with risk classification and it can predict progression after surgery.

Growth arrest and apoptosis induced by kinesin Eg5 inhibitor K858 and by its 1,3,4-thiadiazoline analogue in tumor cells.

Tumors are complex and heterogeneous but, despite this, they share the ability to proliferate continuously, irrespective of the presence of growth signals, leading to a higher fraction of actively growing and dividing cells compared with normal tissues. For this reason, the cytotoxic antimitotic treatments remain an important clinical tool for tumors. Among these drugs, antitubulin compounds constitute one of the most effective anticancer chemotherapies; however, they cause dose-limiting side effects. Therefore, it is still necessary to develop compounds with new targets and new mechanisms of action to reduce side effects or chemoresistance. Mitosis-specific kinesin Eg5 can represent an attractive target for discovering such new anticancer agents because its role is fundamental in mitotic progression. Therefore, we analyzed the effects induced by an inhibitor of kinesin Eg5, K858, and by its 1,3,4-thiadiazoline analogue on human melanoma and prostate cancer cell lines. We found that both compounds have an antiproliferative effect, induce apoptosis, and can determine a downmodulation of survivin.

The kinesin Eg5 inhibitor K858 induces apoptosis but also survivin-related chemoresistance in breast cancer cells.

Inhibitors of kinesin spindle protein Eg5 are characterized by pronounced antitumor activity. Our group has recently synthesized and screened a library of 1,3,4-thiadiazoline analogues with the pharmacophoric structure of K858, an Eg5 inhibitor. We herein report the effects of K858 on four different breast cancer cell lines: MCF7 (luminal A), BT474 (luminal B), SKBR3 (HER2 like) and MDA-MB231 (basal like). We demonstrated that K858 displayed anti-proliferative activity on every analyzed breast cancer cell line by inducing apoptosis. However, at the same time, we showed that K858 up-regulated survivin, an anti-apoptotic molecule. We then performed a negative regulation of survivin expression, with the utilization of wortmannin, an AKT inhibitor, and obtained a significant increase of K858-dependent apoptosis. These data demonstrate that K858 is a potent inhibitor of replication and induces apoptosis in breast tumor cells, independently from the tumor phenotype. This anti-proliferative response of tumor cells to K858 can be limited by the contemporaneous over-expression of survivin; consequently, the reduction of survivin levels, obtained with AKT inhibitors, can sensitize tumor cells to K858-induced apoptosis.

Breast cancer cells respond differently to docetaxel depending on their phenotype and on survivin upregulation.

Breast cancer is characterized by molecular heterogeneity, and four major breast cancer subtypes have been identified, each characterized by significant differences in survival, prognosis, and response to therapy. We have studied the effects of docetaxel treatment on apoptosis and survivin expression in four breast cancer cell lines: MCF7 (luminal A: estrogen receptor-positive and progesterone receptor-positive, ErbB2-negative), BT474 (luminal B: estrogen receptor/progesterone receptor/ErbB2-positive), SKBR3 (HER2-like: estrogen receptor/progesterone receptor-negative, ErbB2-positive), and MDA-MB231 (basal-like: estrogen receptor/progesterone receptor/ErbB2-negative). We demonstrated that docetaxel-induced apoptosis and survivin upregulation (MCF7 p = 0.002, BT474 p = 0.001, SKBR3 p = 0.001) in luminal A/B and HER2-like cells, while it induced mainly necrosis and a lower rate of survivin upregulation (MDA-MB231 p = 0.035) in basal-like cells. Wortmannin, a p-Akt inhibitor, was able to revert surviving upregulation and, at the same time, induced an increase of docetaxel-dependent apoptosis, suggesting that reduced levels of survivin can sensitize tumor cells to apoptosis. These data show that the analyzed breast cancer cell lines respond differently to docetaxel, depending on their receptor expression profile and molecular phenotype. Yet, these data confirm that one of the pathways involved in taxane-related chemoresistance is the upregulation of survivin. Further studies on the molecular mechanisms of chemoresistance and on the different modalities of apoptosis induced by chemotherapeutic agents are requested to better understand how cancer cells evade cell death, in order to design new kind of anticancer agents and survivin could represent a future target for this kind of research.

[Retracted] Resistance to the mTOR inhibitor everolimus is reversed by the downregulation of survivin in breast cancer cells.

[This retracts the article DOI: 10.3892/ol.2017.6597.].

Effect of 1-MHz ultrasound on the proinflammatory interleukin-6 secretion in human keratinocytes.

Keratinocytes, the main cell type of the skin, are one of the most exposed cells to environmental factors, providing a first defence barrier for the host and actively participating in immune response. In fact, keratinocytes express pattern recognition receptors that interact with pathogen associated molecular patterns and damage associated molecular patterns, leading to the production of cytokines and chemokines, including interleukin (IL)-6. Herein, we investigated whether mechanical energy transported by low intensity ultrasound (US) could generate a mechanical stress able to induce the release of inflammatory cytokine such IL-6 in the human keratinocyte cell line, HaCaT. The extensive clinical application of US in both diagnosis and therapy suggests the need to better understand the related biological effects. Our results point out that US promotes the overexpression and secretion of IL-6, associated with the activation of nuclear factor-κB (NF-κB). Furthermore, we observed a reduced cell viability dependent on exposure parameters together with alterations in membrane permeability, paving the way for further investigating the molecular mechanisms related to US exposure.

Antifolate SERS-active nanovectors: quantitative drug nanostructuring and selective cell targeting for effective theranostics.

One of the frontiers of nanomedicine is the rational design of theranostic nanovectors. These are nanosized materials combining diagnostic and therapeutic capabilities, i.e. capable of tracking cancer cells and tissues in complex environments, and of selectively acting against them. We herein report on the preparation and application of antifolate plasmonic nanovectors, made of functionalized gold nanoparticles conjugated with the folic acid competitors aminopterin and methotrexate. Due to the overexpression of folate binding proteins on many types of cancer cells, these nanosystems can be exploited for selective cancer cell targeting. The strong surface enhanced Raman scattering (SERS) signature of these nanovectors acts as a diagnostic tool, not only for tracing their presence in biological samples, but also, through a careful spectral analysis, to precisely quantify the amount of drug loaded on a single nanoparticle, and therefore delivered to the cells. Meanwhile, the therapeutic action is implemented based on the strong toxicity of antifolate drugs. Remarkably, supplying the drug in the nanostructured form, rather than as a free molecule, enhances its specific toxicity. The selectivity of the antifolate nanovectors can be optimized by the design of a hybrid folate/antifolate coloaded nanovector for the specific targeting of folate receptor α, which is overexpressed on numerous cancer cell types.

PLGA based particles as "drug reservoir" for antitumor drug delivery: characterization and cytotoxicity studies.

Doxorubicin (DOX) is commonly used to treat several tumor types, but its severe side effects, primarily cardiotoxicity, represent a major limitation for its use in clinical settings. In this study we developed and characterized biodegradable and stable poly(D,L-lactic-co-glycolic) acid (PLGA) submicrocarriers employing an osmosis-based patented methodology, which allowed to optimize the drug loading efficiency up to 99%. Proceeding from this, we evaluated on MCF-7, a human breast cancer cell line, the ability of PLGA to promote the internalization of DOX and to improve its cytotoxicity in vitro. We found that the in vitro uptake efficiency is dramatically increased when DOX is loaded within PLGA colloidal carriers, which adhere to the cell membrane behaving as an efficient drug reservoir. In fact, the particles provide a diffusion-driven, sustained release of DOX across the cell membrane, resulting in high drug concentration. Accordingly, the cytotoxic analysis clearly showed that DOX-loaded PLGA exhibit a lower 50% inhibitory concentration than free DOX. The decay time of cell viability was successfully compared with DOX diffusion time constant from PLGA. The overall in vitro results highlight the potential of DOX-loaded PLGA particles to be employed as vectors with improved antitumor efficacy.

Androgen receptor variant 7 (AR-V7) in sequencing therapeutic agents for castratrion resistant prostate cancer: A critical review.

BACKGROUND: androgen receptor variant 7 (AR-V7) has been suggested as potential marker for treatment selection in men with metastatic castration-resistant prostate cancer (mCRPC). The aim of the present review is to critically analyze: frequency of the AR-V7 expression in mCRPC cases-impact of AR-V7 expression on abiraterone, enzalutamide, and taxane therapy. METHODS: we searched in the Medline and Cochrane Library database from the literature of the past 10 years. We critically evaluated the level of evidence according to the European Association of Urology (EAU) guidelines. RESULTS: 12 clinical trials were selected. The determination of AR-V7 in peripheral blood using circulating tumor cells mRNA seems to be the preferred method. At baseline, the mean percentage of cases with AR-V7 positivity was 18.3% (range 17.8%-28.8%). All data on mCRPC submitted to enzalutamide or abiraterone reported a significantly (P <.05) lower clinical progression-free survival (CPFS) and overall survival (OS) in AR-V7+ than AR-V7- cases (CPFS hazard ratio [HR]: 2.3; 95% CI 1.1-4.9; OS HR: 3.0; 95% CI 1.4-6.3). In mCRPC cases submitted to chemotherapies data are not homogeneous and some studies showed no association between CPFS or OS and AR-V7 status (OS HR 1.6; 95% CI 0.6-4.4; P = .40). CONCLUSIONS: the suggestion is that taxane therapy is more efficacious than abiraterone or enzalutamide for men with AR-V7+ CRPC. On the contrary, clinical outcomes did not seem to differ significantly on the basis of the type of therapy used among AR-V7- cases.

UVB-radiation-induced apoptosis in Jurkat cells: a coordinated fourier transform infrared spectroscopy-flow cytometry study.

We studied the induction of apoptosis in Jurkat cells by UVB radiation (wavelength 290-320 nm) at a dose of 310 mJ/ cm2. We combined Fourier transform infrared (FTIR) spectroscopy with flow cytometry to determine whether the combination of both techniques could provide new and improved information about cell modifications. To do this, we looked for correspondences and correlations between spectroscopy and flow cytometry data and found three highly probable spectroscopic markers of apoptosis. The behavior of the wave number shift of both the Amide I beta-sheet component and the area of the 1083 cm(-1) band reproduced, with a high correlation, the behavior of the early apoptotic cell population, while the behavior of the Amide I area showed a high correlation with the early plus late apoptotic cell population.

Failure of apoptosis and activation on NFkappaB by celecoxib and aspirin in lung cancer cell lines.

Recent studies have demonstrated that antineoplastic activity of Cox-2 inhibitors may depend on targets other than Cox: among those, nuclear factor kappaB (NFkappaB) seems the most promising. Although preclinical studies have suggested that aspirin and Cox-2 inhibitors may influence the progression of lung cancer, the molecular mechanisms of these protective effects in this tumor type has not been fully elucidated. We investigated the effects of celecoxib and aspirin in the induction of apoptosis and in the ability to activate NFkappaB in three non-small cell lung cancer cell lines. Apoptosis was evaluated by FACS, caspase activation assay and expression of apoptosis-related genes by RT-PCR, while NFkappaB activation was assessed by immunofluorescence. No apoptotic response was observed after treatment with both high and low dose of celecoxib. Nevertheless, celecoxib at both concentrations induced a strong NFkappaB activation, with increased expression of NFkappaB-dependent genes, such as bcl-2, bcl-XL and survivin. Similarly, aspirin at both concentrations did not induce any apoptotic response, but activated NFkappaB in a dose-dependent manner. This study supports the hypothesis that NFkappaB activation is an important effect of NSAIDs in lung cancer, leading to apoptosis resistance. This effect of both aspirin and celecoxib may be considered undesirable in lung cancer chemoprevention.

Resistance to the mTOR inhibitor everolimus is reversed by the downregulation of survivin in breast cancer cells.

Everolimus (RAD001) is an inhibitor of mammalian target of rapamycin used in combination with exemestane to treat hormone receptor-positive advanced breast cancer. However, not all patients are equally sensitive to RAD001 and certain patients develop resistance. Therefore, the present study analyzed the mechanisms involved in the resistance of breast cancer cells to RAD001 in order to identify a potential tool to overcome it. The effects of RAD001 on the inhibition of cell viability, on the induction of apoptosis and autophagy and on the regulation of survivin, an anti-apoptotic protein, were evaluated in two breast cancer cell lines: BT474 (luminal B) and MCF7 (luminal A). RAD001 was demonstrated to induce autophagy in the two cell lines at following a short period of treatment (4 h) and to induce apoptosis exclusively in BT474 cells following longer periods of treatment (48 h). RAD001 induced the downregulation of survivin in BT474 cells and its upregulation in MCF7 cells. Consequently, inhibiting survivin with YM155 resulted in the acquired resistance of MCF7 cells to RAD001 being reverted, restoring RAD001-induced apoptosis. These data demonstrated that RAD001 exerted anti-proliferative and pro-apoptotic effects on breast cancer cells, but that these effects were repressed by the simultaneous up-regulation of survivin. Finally, the results demonstrated that inhibiting the expression of survivin resulted in the restoration of the anti-neoplastic activity of RAD001.

A Perspective of Immunotherapy for Prostate Cancer.

In cancer patients, the immune system is often altered with an excess of inhibitory factors, such as immunosuppressive cytokines, produced by regulatory T cells (Treg) or myeloid-derived suppressor cells (MDSC). The manipulation of the immune system has emerged as one of new promising therapies for cancer treatment, and also represents an attractive strategy to control prostate cancer (PCa). Therapeutic cancer vaccines and immune checkpoint inhibitors have been the most investigated in clinical trials. Many trials are ongoing to define the effects of immune therapy with established treatments: androgen deprivation therapy (ADT) and chemotherapy (CT) or radiotherapy (RT). This article discusses some of these approaches in the context of future treatments for PCa.

Prognostic value of inflammation in prostate cancer progression and response to therapeutic: a critical review.

Prostate is an immune-competent organ normally populated by inflammatory cells. Prostatic inflammation origin can be multi-factorial and there are some emerging evidences on its possible role as a factor involved in prostate cancer (PC) pathogenesis and progression. This review critically analyzes the role of inflammation as a prognostic factor for progression and aggressiveness of PC. We verified the last 10 years literature data on the association between inflammation and PC aggressiveness, or PC response to therapies. Several studies tried to correlate different inflammatory factors with the aggressiveness and metastatization of PC; all data sustain the role of inflammation in PC progression but they also produce confusion to identify a reliable clinical prognostic marker. Data on patients submitted to radical prostatectomy (RP) showed that cases with marked intraprostatic tissue inflammation are associated with higher rate of biochemical progression; systemic inflammation markers appear to have a significant prognostic value. Analyzing data on patients submitted to radiotherapy (RT) emerges a significant association between high neuthrophil to lymphocyte ratio (NLR) and decreased progression free survival and overall survival; also plateled to lymphocyte ratio (PLR) and C-reactive protein (CRP) have been proposed as significant prognostic factors for progression and overall survival. In patients submitted to androgen deprivation therapy (ADT), inflammation may drive castration resistant PC (CRPC) development by activation of STAT3 in PC cells. NLR has been proposed as independent predictor of overall survival in CRPC submitted to chemotherapy. Most of data are focused on markers related to systemic inflammation such as NLR and CRP, more than specifically to chronic prostatic inflammation. The suggestion is that these inflammatory parameters, also if not specific for prostatic inflammation and possibly influenced by several factors other than PC, can integrate with established prognostic factors.

Tenascin C and epidermal growth factor receptor as markers of circulating tumoral cells in bladder and colon cancer.

Tenascin C has been recently suggested as a tumor marker, however, its levels in serum has been evaluated only in patients with head and neck cancer and melanoma. In this study, we investigated Tenascin C expression in blood samples from colorectal and bladder cancer patients, compared to that of epidermal growth factor receptor (EGFR), a known circulating tumor marker in these cancer types. RT-PCR specific for Tenascin C and EGFR was performed on RNAs extracted from blood samples of 60 patients affected by colon or bladder cancer. We then investigated the statistical association between Tenascin C, EGFR expression and disease-free survival using the Kaplan-Meier method. Furthermore, in order to select which variable between EGFR and Tenascin C was the most predictive for recurrence, a Cox model for proportional risk was applied. Among all patients analysed, a significantly higher disease-free time was found in the group negative for both EGFR and Tenascin C expression; EGFR expression was significantly correlated to disease progression in stages III and IV, whereas in all patients with stage I and II disease Tenascin C correlated better with prognosis. Negative expression of both EGFR and Tenascin C identifies a group of patients with poor tendency to disease recurrence and longer relapse-free time. While Tenascin C expression seems to influence prognosis in patients with low-stage disease, EGFR appears a marker of worse prognosis in patients with high-staged tumors.

UDP-glucuronosyltransferases 1A expression in human urinary bladder and colon cancer by immunohistochemistry.

UDP-glucuronosyltrasferases (UGTs) are detoxifying enzymes, which convert endogenous substrates, dietary constituents and potential carcinogens to inactive hydrophilic glucuronides. Although the liver is considered the most important organ for glucuronidation, UGTs are also expressed in extrahepatic tissues. Since UGTs may be important to protect cells from cancer in organs naturally exposed to potential carcinogens such as smoking and diet derivatives, we investigated the UGT expression in normal and malignant tissues from urinary bladder and large intestine. The study was carried out by immunohistochemistry, using an antiserum recognizing all the UGT1A isoforms. Our results showed that UGTs were highly expressed on the surfaces of the normal bladder as well as in normal large bowel mucosa. The neoplastic counterpart showed a general protein down-regulation associated with a different cellular localization. We found that 3/11 papillary and 3/6 invasive urothelial carcinomas were virtually negative, whereas 2/2 papillomas and 8/11 papillary bladder carcinomas still expressed the protein. In colon cancer the enzyme down-regulation was even more dramatic. In fact, a faint diffused cytoplasmic expression or scattered cell positivity was observed only in adenomas with low grade dysplasia (5/5) and in 2/11 carcinomas. Interestingly, 5/5 adenomas with high grade dysplasia, 9 carcinomas, the lymph nodes and liver metastases were UGT-negative, suggesting that the loss of UGT is associated with the early phase of neoplastic transformation. Based on our results we suggest that UGTs constitutive expression in the normal mucosa could protect these organs from carcinogens released in the bladder or introduced directly with the diet in the colon.

Beyond the Immune Suppression: The Immunotherapy in Prostate Cancer.

Prostate cancer (PCa) is the second most common cancer in men. As well in many other human cancers, inflammation and immune suppression have an important role in their development. We briefly describe the host components that interact with the tumor to generate an immune suppressive environment involved in PCa promotion and progression. Different tools provide to overcome the mechanisms of immunosuppression including vaccines and immune checkpoint blockades. With regard to this, we report results of most recent clinical trials investigating immunotherapy in metastatic PCa (Sipuleucel-T, ipilimumab, tasquinimod, Prostvac-VF, and GVAX) and provide possible future perspectives combining the immunotherapy to the traditional therapies.

Synthesis and pharmacological screening of a large library of 1,3,4-thiadiazolines as innovative therapeutic tools for the treatment of prostate cancer and melanoma.

Antimitotic agents are widely used in cancer chemotherapy but the numerous side effects and the onset of resistance limit their clinical efficacy. Therefore, with the purpose of discovering more selective and efficient anticancer agents to be administered alone or in combination with traditional drugs, we synthesized a large library of 1,3,4-thiadiazoline analogues, maintaining the pharmacophoric structure of an antiproliferative compound known as K858: this is a new inhibitor of kinesin Eg5, able to induce the mitotic arrest in colorectal cancer cells and in xenograft ovarian cancer cells. We screened 103 compounds to assess their antiproliferative activity on PC3 prostate cancer cell line. Two derivatives, compounds 32 (corresponding to K858) and 33, have shown to be the most effective against prostate tumor cells and also towards two melanoma cell lines (SK-MEL-5 and SK-MEL-28) at low micromolar concentrations, confirming the pharmacological activity of this scaffold and revealing the potential role of 1,3,4-thiadiazolines in the management of cancer.

Detection of CK19, CK20 and EGFR mRNAs in peripheral blood of carcinoma patients: correlation with clinical stage of disease.

Expression of genes such as cytokeratin 19 (CK19), cytokeratin 20 (CK20) and epidermal growth factor receptor (EGFR) has been investigated at mRNA level in peripheral blood of carcinoma patients to detect the presence of circulating tumor cells (CTC). We performed this study because recent literature emphasizes that the importance of CK19, 20 and EGFR mRNAs in CTC as prognostic factors remains unclear especially for breast, head and neck and colon cancer patients. Reverse transcriptase polymerase chain reaction (RT-PCR) followed by Southern blot hybridization was performed in blood samples from 47 subjects (12 colorectal, 15 head and neck and 20 breast carcinoma patients), as well as in 35 healthy donors. The CK19 expression was found in 36/47 patients (9 colorectal, 9 head and neck and 18 breast cancer), two patients (one affected by colorectal and one by head and neck cancer) were positive for CK20 whereas EGFR was found expressed in 9 patients (3 colorectal, 5 head and neck and one breast cancer). Seven of 35 and 4/35 healthy donors displayed positivity for the expression of CK19 and CK20 genes respectively, whereas no EGFR mRNA was found in this group. The correlation of the detection of CTC in peripheral blood with progression of the disease in a follow-up period of 40 months did not show any prognostic value to the presence of mRNAs of these biomarkers in blood. We believe that research should be addressed, at least for breast cancer, to the identification of occult metastases in sentinel lymph nodes, such as recently performed in melanoma patients.