On the origin of metastases: Induction of pro-metastatic states after impending cell death via ER stress, reprogramming, and a cytokine storm

How metastatic cells arise is unclear. Here, we search for the induction of recently characterized pro-metastatic states as a surrogate for the origin of metastasis. Since cell-death-inducing therapies can paradoxically promote metastasis, we ask if such treatments induce pro-metastatic states in human colon cancer cells. We find that post-near-death cells acquire pro-metastatic states (PAMEs) and form distant metastases in vivo. These PAME ("let's go" in Greek) cells exhibit a multifactorial cytokine storm as well as signs of enhanced endoplasmic reticulum (ER) stress and nuclear reprogramming, requiring CXCL8, INSL4, IL32, PERK-CHOP, and NANOG. PAMEs induce neighboring tumor cells to become PAME-induced migratory cells (PIMs): highly migratory cells that re-enact the storm and enhance PAME migration. Metastases are thus proposed to originate from the induction of pro-metastatic states through intrinsic and extrinsic cues in a pro-metastatic tumoral ecosystem, driven by an impending cell-death experience involving ER stress modulation, metastatic reprogramming, and paracrine recruitment via a cytokine storm.

Functional Pro-metastatic Heterogeneity Revealed by Spiked-scRNAseq Is Shaped by Cancer Cell Interactions and Restricted by VSIG1

How cells with metastatic potential, or pro-metastatic states, arise within heterogeneous primary tumors remains unclear. Here, we have used one index primary colon cancer to develop spiked-scRNAseq to link omics-defined single-cell clusters with cell behavior. Using spiked-scRNAseq we uncover cell populations with differential metastatic potential in which pro-metastatic states are correlated with the expression of signaling and vesicle-trafficking genes. Analyzing such heterogeneity, we define an anti-metastatic, non-cell-autonomous interaction originating from non-/low-metastatic cells, and identify membrane VSIG1 as a critical mediator of this interaction. VSIG1 acts to restrict the development of pro-metastatic states autonomously and non-cell autonomously, in part by inhibiting YAP/TAZ-TEAD signaling. As VSIG1 re-expression is able to reduce metastatic behavior from multiple colon cancer cell types, the regulation of VSIG1 or its effectors opens new interventional opportunities. In general, we propose that crosstalk between cancer cells, including the action of VSIG1, dynamically defines the degree of pro-metastatic intra-tumoral heterogeneity.

The protein secretion modulator TMED9 drives CNIH4/TGFα/GLI signaling opposing TMED3-WNT-TCF to promote colon cancer metastases

How cells in primary tumors initially become pro-metastatic is not understood. A previous genome-wide RNAi screen uncovered colon cancer metastatic suppressor and WNT promoting functions of TMED3, a member of the p24 ER-to-Golgi protein secretion family. Repression of canonical WNT signaling upon knockdown (kd) of TMED3 might thus be sufficient to drive metastases. However, searching for transcriptional influences on other family members here we find that TMED3 kd leads to enhanced TMED9, that TMED9 acts downstream of TMED3 and that TMED9 kd compromises metastasis. Importantly, TMED9 pro-metastatic function is linked to but distinct from the repression of TMED3-WNT-TCF signaling. Functional rescue of the migratory deficiency of TMED9 kd cells identifies TGFα as a mediator of TMED9 pro-metastatic activity. Moreover, TMED9 kd compromises the biogenesis, and thus function, of TGFα. Analyses in three colon cancer cell types highlight a TMED9-dependent gene set that includes CNIH4, a member of the CORNICHON family of TGFα exporters. Our data indicate that TGFA and CNIH4, which display predictive value for disease-free survival, promote colon cancer cell metastatic behavior, and suggest that TMED9 pro-metastatic function involves the modulation of the secretion of TGFα ligand. Finally, TMED9/TMED3 antagonism impacts WNT-TCF and GLI signaling, where TMED9 primacy over TMED3 leads to the establishment of a positive feedback loop together with CNIH4, TGFα, and GLI1 that enhances metastases. We propose that primary colon cancer cells can transition between two states characterized by secretion-transcription regulatory loops gated by TMED3 and TMED9 that modulate their metastatic proclivities.

The histone methyltransferase EZH2 as a druggable target in SHH medulloblastoma cancer stem cells

The histone methyltransferase EZH2 plays a role in maintenance of the stem component of cancer, and its overexpression and/or mutation typically drives tumor aggressiveness, drug resistance and patients’ poor prognosis. In this study, we use mouse and human medulloblastoma stem-like cells belonging to the Sonic Hedgehog subgroup (SHH MB-SLCs) and demonstrate that genetic suppression of EZH2 reduces the level of its histone mark H3K27me3 and lowers proliferation and self-renewal. We designed an EZH2 inhibitor (EZH2i) as a simplified analog of EPZ005687 and GSK2816126, MC3629, and we tested its biological activity in SHH MB-SLCs. Pharmacological inhibition of EZH2 impairs SHH MB cells proliferation and self-renewal, and induces apoptosis in vitro. Finally, we generated xenograft MB-SLCs orthotopic tumors in nude mice to test MC3629 in vivo. In treated mice, we observed impairment of tumor growth, together with induction of apoptosis and reduction of proliferation and stemness.

Overall, these findings describe EZH2 as a druggable target in MB and provide insight into the biological activity of MC3629 as an EZH2i.

Abstract 2484: Non-canonical Hedgehog/Gli1 signaling drives lung adenocarcinoma stem cells survival and its targeting inhibits CSC-derived tumors

Introduction: Lung Adenocarcinoma (AC) is the most frequent lung cancer histological subtype and is a leading cause of cancer-related death worldwide. Hedgehog/Gli (Hh/Gli) signaling pathway regulates lung development and its aberrant activation contributes to tumor pathogenesis and play a role in cancer stem cells (CSC) control.

We investigated oncogenic Hh/Gli signaling in AC-CSC.

Methods: human AC-CSC were derived from primary tumors. For in vitro studies AC-CSC were maintained in serum-free medium supplemented with EGF/bFGF. For in vivo experiments, immunocompromised mice were injected with AC-CSC. Gli1 inhibitor GANT61 was used both in vitro and in vivo (IP 40 mg/kg twice/we) treatments.

Results: Using mRNA datasets and tissue microarray of Non-small Cell Lung Cancer (NCSLC) samples we found that in AC Gli1 is expressed independently of its canonical activator Smoothened (Smo) expression level. Similarly, CSC were Gli1 positive regardless of Smo expression levels. Indeed, we found that SMO regulatory region is highly methylated in AC cells where Smo mRNA and protein are low.

Looking for Smo-independent regulation of GLI activity we found that NRP2/Erk and IGF1R/Erk axes regulate Gli1 in AC-CSC. Suppression of Gli1 with GANT61 in CSC resulted in impairment of cell growth and stemness features. We performed in-vivo experiments: CSC-derived xenograft from GANT61 treated mice showed impaired tumor growth, reduced proliferation and increased apoptosis. We next highlighted a tumor-stroma crosstalk. A positive autocrine oncogenic feedback loop sustains Gli1 in AC-CSC since we found that the CSC expressed NRP2 and its ligands VEGF-A and VEGF-C. A paracrine positive loop also sustain Hh/Gli signaling in AC where Cancer-Associated Fibroblasts (CAFs) harbor Hh/Gli1 canonical pathway that regulates the expression of VEGF-A, VEGF-C and IGF2 ligands of NRP2 and IGF1R respectively.

Conclusion: Our findings suggest a non-canonical activation of Hh/Gli pathway in AC. In this context, GLI1 transcription factor is effectors of NRP2/Erk and/or IGF1R/Erk signaling inputs.

Our results have implications for the understanding of AC development and sustain the inclusion of target therapy acting downstream of Smo level in the design of AC treatment.

Citation Format: Agnese Po, Marianna Silvano, Evelina Miele, Adriana Eramo, Matilde Todaro, Carlo Capalbo, Valentina Salvati, Giovanni Sette, Danilo Cucchi, Zein M. Besharat, Gianluca Canettieri, Lucia Di Marcotullio, Isabella Screpanti, Giorgio Stassi, Ruggero De Maria, Ann Zeuner, Enrico De Smaele, Elisabetta Ferretti. Non-canonical Hedgehog/Gli1 signaling drives lung adenocarcinoma stem cells survival and its targeting inhibits CSC-derived tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2484.

Molecular Diversity and Associated Phenotypic Spectrum of Germline CBL Mutations

Noonan syndrome (NS) is a relatively common developmental disorder with a pleomorphic phenotype. Mutations causing NS alter genes encoding proteins involved in the RAS-MAPK pathway. We and others identified Casitas B-lineage lymphoma proto-oncogene (CBL), which encodes an E3-ubiquitin ligase acting as a tumor suppressor in myeloid malignancies, as a disease gene underlying a condition clinically related to NS. Here, we further explored the spectrum of germline CBL mutations and their associated phenotype. CBL mutation scanning performed on 349 affected subjects with features overlapping NS and no mutation in NS genes allowed the identification of five different variants with pathological significance. Among them, two splice-site changes, one in-frame deletion, and one missense mutation affected the RING domain and/or the adjacent linker region, overlapping cancer-associated defects. A novel nonsense mutation generating a v-Cbl-like protein able to enhance signal flow through RAS was also identified. Genotype-phenotype correlation analysis performed on available records indicated that germline CBL mutations cause a variable phenotype characterized by a relatively high frequency of neurological features, predisposition to juvenile myelomonocytic leukemia, and low prevalence of cardiac defects, reduced growth, and cryptorchidism. Finally, we excluded a major contribution of two additional members of the CBL family, CBLB and CBLC, to NS and related disorders.

High-throughput microRNA profiling of pediatric high-grade gliomas

BACKGROUND

High-grade gliomas (HGGs) account for 15% of all pediatric brain tumors and are a leading cause of cancer-related mortality and morbidity. Pediatric HGGs (pHGGs) are histologically indistinguishable from their counterpart in adulthood. However, recent investigations indicate that differences occur at the molecular level, thus suggesting that the molecular path to gliomagenesis in childhood is distinct from that of adults. MicroRNAs (miRNAs) have been identified as key molecules in gene expression regulation, both in development and in cancer. miRNAs have been investigated in adult high-grade gliomas (aHGGs), but scant information is available for pHGGs.

METHODS

We explored the differences in microRNAs between pHGG and aHGG, in both fresh-frozen and paraffin-embedded tissue, by high-throughput miRNA profiling. We also evaluated the biological effects of miR-17-92 cluster silencing on a pHGG cell line.

RESULTS

Comparison of miRNA expression patterns in formalin versus frozen specimens resulted in high correlation between both types of samples. The analysis of miRNA profiling revealed a specific microRNA pattern in pHGG with an overexpression and a proliferative role of the miR-17-92 cluster. Moreover, we highlighted a possible quenching function of miR-17-92 cluster on its target gene PTEN, together with an activation of tumorigenic signaling such as sonic hedgehog in pHGG.

CONCLUSIONS

Our results suggest that microRNA profiling represents a tool to distinguishing pediatric from adult HGG and that miR-17-92 cluster sustains pHGG.

Risk stratification in arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic cardiomyopathy characterized by myocyte death and fibrofatty replacement mostly in the right ventricle. It is a leading cause of sudden cardiac death (SCD) in individuals under the age of 35 years. The main goal in the treatment of the disease is the prevention of SCD. An implantable cardioverter-defibrillator (ICD) is the only proven life-saving therapeutic option able to improve survival in ARVC patients. This therapy is not free from side effects and it accounts for a relatively high rate of morbidity because of the occurrence of inappropriate ICD interventions and of complications, both at implantation and during the follow-up. In recent years, the approach to ICD implantation has been changing on the basis of new emerging data on risk stratification. The usefulness of ICD implantation for secondary prevention has been definitively proven; the most challenging question is how to treat patients with no history of previous cardiac arrest or hemodynamically unstable ventricular tachycardia (VT). The value of ECG abnormalities, syncope, VT, and right/left ventricular involvement as predictors of SCD has been assessed in different studies with the purpose of better defining risk stratification in ARVC. Nevertheless, in spite of the growing amount of data, primary prevention in ARVC patients remains mostly an individual decision.

microRNA-17-92 cluster is a direct Nanog target and controls neural stem cell through Trp53inp1

The transcription factor Nanog plays a critical role in the self-renewal of embryonic stem cells as well as in neural stem cells (NSCs). microRNAs (miRNAs) are also involved in stemness regulation. However, the miRNA network downstream of Nanog is still poorly understood. High-throughput screening of miRNA expression profiles in response to modulated levels of Nanog in postnatal NSCs identifies miR-17-92 cluster as a direct target of Nanog. Nanog controls miR-17-92 cluster by binding to the upstream regulatory region and maintaining high levels of transcription in NSCs, whereas Nanog/promoter association and cluster miRNAs expression are lost alongside differentiation. The two miR-17 family members of miR-17-92 cluster, namely miR-17 and miR-20a, target Trp53inp1, a downstream component of p53 pathway. To support a functional role, the presence of miR-17/20a or the loss of Trp53inp1 is required for the Nanog-induced enhancement of self-renewal of NSCs. We unveil an arm of the Nanog/p53 pathway, which regulates stemness in postnatal NSCs, wherein Nanog counteracts p53 signals through miR-17/20a-mediated repression of Trp53inp1.

Direct control of the miRNA-17/92 cluster enables Nanog to restrain p53 activity and thus to maintain pluripotency in neural stem cells.

[Radiotherapy of stage T1 carcinoma of the glottis. Analysis of prognostic factors in 154 patients]

A retrospective study was carried out on a series of 154 patients affected with vocal cord cancer in stage T1 treated with definitive radiotherapy April, 1979, to November, 1991. According to the 1992 TNM classification (UICC), 121 patients were classified as stage T1a and 33 patients as stage T1b. All patients were treated using parallel opposed fields of a 60 cobalt unit. Field size ranged from 16 to 30 square centimeters and the dose from 4400 to 7000 cGy, but only 15 patients received less than 6400 cGy. All patients were treated with once-daily fractionation (200 cGy/day). Follow-up ranges from 25 to 123 months; the median is 63 months. We observed 14 local recurrences (9.0%), all but one within 36 months from the end of treatment. Ten of 14 patients (71.4%) were rescued by surgery (8 patients underwent total laryngectomy and 2 conservative surgery); 13 patients were lost for intercurrent deaths. The incidence of recurrences is 7.4% for T1a patients (9/121) and 15.1% for T1b patients (5/33). The total dose does not seem to be related to relapse rate since recurrences were found in 6.6% of patients after a dose < 6400 cGy and in 9.3% of patients who had received higher doses. In our experience, field size did not affect, treatment results (< 25 cm2: 7.5% recurrences, > 25 cm2: 10.7%). Besides lesion volume, the main prognostic factor was overall treatment time. The incidence of failure was 3 times lower (5.8%) in the patients who completed the treatment within 7 weeks than in the patients whose treatment lasted more than 8 weeks (16.6%).

[Combined treatment of stage I and II gastric lymphoma]

From 1981 to 1991, fifty-three patients with primary gastric lymphoma were referred to our Institute and submitted to a complete pathologic staging followed by gastric resection, i.e., total or partial gastrectomy. According to the Working Formulation criteria, 14 patients (26.4%) were affected with high grade lymphomas, 22 (41.5%) with intermediate lymphomas and 17 (32.1%) with low grade lymphomas. MALT (mucosa associated lymphoid tissue) lymphomas were observed in > 50% of cases. At the pathologic examination of the surgical specimens, infiltration depth was assessed, according to TNM criteria, in the patients whose disease was limited to the muscular gastric wall (T1-T2) and in those whose disease spread to the serosa or beyond it (T3-T4). Twenty-five patients were classified as stage I and 28 as stage II (9 of them in stage II E1 and 19 in stage II E2 according to Musshoff's classification). The treatment protocol of these patients was as follows: stage I patients (T1-T2) with normal surgical resection margins underwent no adjuvant treatment (10 patients); stage I patients (T1-T2) with resection margins infiltrated by the disease were submitted to local irradiation; stage I (T3-T4) and stage II E1 patients underwent large-field postoperative irradiation (14 patients); stage II E2 patients (n = 19) received conventional chemotherapy (CHOP, F-CVP, N-CVP): the ones who failed to reach complete remission or presented with bulky disease at diagnosis completed the treatment with large-field irradiation (10 patients). The disease-free survival (86.5%) and the overall survival (96%) rates of stage I patients exhibited no significant difference relative to stage II patients (DFS: 87% and OS: 90%). The analysis of relapses relative to disease extent demonstrated that this parameter is more significant to prognosis than nodal involvement (T1-T2: 2/39 relapses, 5.1%; T3-T4: 4/14 relapses, 28.6%).

[Analysis of prognostic factors in 106 cases of carcinoma of the rhinopharynx treated with cobalt teletherapy]

A series of 106 patients affected with nasopharyngeal carcinomas and treated by definitive external irradiation from January 1975 to December 1986 was retrospectively reviewed. The median follow-up, from the end of the treatment, was 43 months (range 24-90). The nasopharynx received not less than 60 Gy to the midplane: the clinically negative neck (N0) was treated with a total dose of 50 Gy and the patients who had N1-3 disease received not less than 60 Gy. Thirty-eight patients had a recurrence in the irradiated areas (31 in the nasopharynx, and 7 in the neck); 17 patients developed distant metastases. Disease-free survival at 60 months was 42%. The most significant prognostic factor (p less than 0.05) was the presence of advanced neck involvement (N2-3), since most of the lymphatic and distant recurrences were observed in this group of patients. The overall results did not reveal but slight differences in the survival according to histology, even though patients with undifferentiated carcinomas had a local recurrence rate significantly lower than those with squamous cell carcinomas. Our findings suggest that patients with N2-3 neck diseases or with locally advanced involvement (T3-4) be treated by adjuvant chemotherapy in order to decrease the risk of local and distant relapses.

[Pre- and postoperative radiotherapy of oral carcinoma of a locally advanced stage. An analysis of the results and complications]

The combination of radiotherapy and surgery in the treatment of advanced oral carcinoma (T3 and T4 lesions) yields good possibilities of recovery; whether radiotherapy should be given before or after surgery is still debated. Fifty patients with advanced oral carcinomas were analyzed: 24 of them were irradiated before and 26 after surgery; doses ranged from 40 to 56 Gy for the first group of patients, and from 50 to 68 Gy for the second one. The disease-free survival 48 months after the diagnosis was 36% in patients who received preoperative irradiation, and 53.6% in patients who received postoperative radiotherapy; the latter allowed local control of the disease to be significantly improved (chi 2 3.99, 0.01 less than p less than 0.05). The quality of survival was worse in the group receiving preoperative irradiation, because of radiation-induced surgical complications, which were especially observed in patients with diffuse disease. Our findings suggest that postoperative radiotherapy may be advisable if the tumor is resectable, since tolerance and local control rate were acceptable. On the contrary, nearly inoperable masses and massive neck diseases often require preoperative irradiation.

[Radiotherapy of carcinoma of the glottis in the initial stage]

The control of early glottic cancer is equally satisfactory with either surgical resection or radiation therapy; this last method gives the patient good functional results. During the period from 1/1978 to 12/1985, 73 patients with early glottic carcinoma (T1 N0 M0) were treated in the Institute of Radiotherapy L. Galvani, University of Bologna; 45 were stage T1a (tumour limited to one vocal cord) and 28 were stage T1b (tumour of both vocal cords or involving anterior commissure); radiation treatment utilised a 60Co machine and 5 x 5 cm fields; the median dose was 67.2 Gy (range 50-76) with conventional fractionation. Ten patients had local recurrence; the median time of recurrence was 13.4 months; 9/10 were treated by surgery and 2/10 died, so the overall control by radiotherapy with surgery in reserve was 100% in T1a tumours and 90.6% in T1b ones. The 5-years disease free survival rate was 93.1% in T1a tumours and 69% in T1b; lesions involving anterior commissure had the worst prognosis, independent of the dose and time-dose factor (3/10 recurrences in the group treated with TDF less than 110 and 4/18 recurrences in the group with TDF more than 110).

Patterns of failure in nasopharyngeal cancer treated with megavoltage irradiation

From 1976 to 1982, 78 patients with nasopharyngeal cancer (NPC) were treated with definitive megavoltage irradiation in accordance with a uniform protocol. The results of treatment were analyzed and prognostic factors reviewed. The incidence of primary failures was directly related to the extent of nasopharyngeal disease, since the relapse rate was 11% in T1T2 patients compared with 37.5% in T3T4 patients. Similarly, failure in the neck correlated with the N stage, being negligible for N0 and N1, while 35.7% for N3. The presence of bulky cervical nodes was associated with a higher risk for metastases: hematogenous dissemination occurred in 50% of N3B patients. The histology pattern seemed to significantly affect the ultimate outcome of patients with NPC, since disease-free survival was 65.5% in patients with a diagnosis of undifferentiated carcinoma (UC) and 23.8% in patients with squamous cell carcinoma (SC). The major cause of poor survival in this latter patient group was not only a higher recurrence rate of both primary and nodal disease but a greater incidence of distant metastases as well.

[Topical dose-control relationship in high-energy radiation therapy of epithelial tumors of the nasopharynx]

The results of megavoltage irradiation at different doses in 188 patients with carcinoma of the nasopharynx treated at the Institute of Radiotherapy "L. Galvani", University of Bologna, from 1960 to 1978, are analyzed. Dose-control relationship is investigated. The incidence of failures at the primary site and in the neck is a function of dose and neoplastic volume: 5,000 rad/5 weeks for sub-clinical disease and 7,000 rad/7 weeks for massive disease appears to eradicate the tumor in a high number of cases. Prognosis of patients with extensive disease in the neck is nevertheless unfavourable, since a great number of them dies for distant metastases. It seems therefore necessary to institute clinical trials testing adjuvant chemotherapy in patients with neck stages N2-N3.

[Incidence of lymph node metastases in epithelial neoplasms of the oral cavity: risk factors]

The incidence of pathological neck nodes metastases in a group of 60 patients with a diagnosis of oral squamous carcinoma is reviewed. Risk factors are a size of primary more than 4 cm and tumors of the anterior two-third of the tongue. Carcinomas of oral tongue, also of a size less than 4 cm (T1,T2), have a high incidence of subclinical metastases.