Translating the Immunobiology of SBRT to Novel Therapeutic Combinations for Advanced Prostate Cancer

Extreme hypofractionated stereotactic radiotherapy for elderly prostate cancer patients: side effects preliminary analysis of a phase II trial

PURPOSE

Aim of this study is to evaluate safety and efficacy of SBRT in elderly patients affected by localized prostate cancer (PC).

MATERIAL AND METHODS

Men aged 70 years or older were enrolled and analyzed. The SBRT schedule was 35 Gy in 5 fractions administered in 1-2 weeks. According to risk group, androgen deprivation therapy (ADT) was prescribed. Urinary symptoms were evaluated at baseline using the International Prostate Symptom Score (IPSS). Genitourinary (GU) and gastrointestinal (GI) toxicities were assessed at the end of treatment, 2 weeks after SBRT and during follow-up using the Common Terminology Criteria for Adverse Events (CTCAE). PSA values were recorded before treatment and during follow-up as biochemical response criteria.

RESULTS

Between 07/2019 and 09/2021, 111 patients were enrolled. Median age was 77 years. At the end of treatment, no acute GU/GI toxicities ≥ G2 were observed. At 2-3 weeks after treatment, 3 patients reported G2 GU toxicity, while 14 patients referred G2 GI toxicity. During the last follow up, 26 and 2 patients reported, respectively, G1 and G2 GU toxicity, while 22 and 1 cases described, respectively, G1 and G2 GI toxicity. No late toxicities ≥ G3 were recorded. GU toxicity is related to absence of urethra sparing, increasing PTV volume, Dmax PTV and IPSS; GI toxicity is related to RT schedule (each other day is better than consecutive day), Dmax rectum and IPSS, At a median follow-up of 24 months, excellent biochemical disease control was achieved in all cases with median PSA of 0.5 ng/ml.

CONCLUSION

SBRT in elderly patients affected by PC is feasible and well tolerated with excellent biochemical disease control. Longer follow-up is needed to assess late toxicity profile and long-term clinical outcome.

Stereotactic Ablative Radiation Therapy in 3 Fractions Induces a Favorable Systemic Immune Cell Profiling in Prostate Cancer Patients

The impact of radiotherapy (RT) on immune cell status in prostate cancer (PCa) is only partially determined. The aim of this study was to assess the effect of different RT strategies on peripheral B, T, and Natural killer (NK) lymphocytes at precise longitudinal time-points in PCa. 18 patients treated with stereotactic body radiation therapy (SBRT) (40 Gy/3FRX), definitive moderate-hypofractionation (62 Gy/20FRX), or post-operative conventional-fractionation RT (66-69 Gy/30FRX) were prospectively evaluated for the immune cell profile in terms of immune cell composition, differentiation stage, cytokine production and inhibitory receptor (IR) expression. The immune-monitoring of the 18 patients revealed that RT affects the balance of systemic immune cells, with the main differences observed between SBRT and conventionally fractionated RT. SBRT favorably impacts immune response in term of increased B cells, central-memory and effector-memory CD8⁺ T cells, along with decreased Treg cells after treatment. On the contrary, conventional fractionated RT had a long-term negative effect on the systemic immune profile, including a decrease of total lymphocyte counts accompanied by an increase of neutrophils-to-lymphocytes ratio. Total B and T cells decreased and Treg-to-CD8⁺ ratio increased. Functionality of T lymphocytes were not affected by any of the 3-fractionation schedules. Interestingly, SBRT significantly up-regulates the expression of V-domain immunoglobulin suppressor of T-cell activation (VISTA) in CD8⁺ T cells in the absence of other IRs. Our results indicate the relevance of systematic immunomonitoring during RT to identify novel immune-related target to design trials of combined radio-immunotherapy as a promising strategy in the clinical management of PCa.

Clinical Study of 3DCRT Combined with SBRT in the Treatment of Patients with EGFR Mutation Oligometastatic Non-Small Cell Lung Cancer

Background

Lung cancer is one of the malignant tumors with the highest morbidity and mortality in my country and the world. Among them, non-small-cell lung cancer (NSCLC) accounts for about 80%. For patients who are diagnosed with NSCLC and have epidermal growth factor receptor, EGFR gene-sensitive mutations The treatment is particularly important.

Aims

To investigate the efficacy and prognosis of 3DCRT combined with local SBRT in patients with EGFR mutation oligometastatic NSCLC.

Materials and Methods

Eighty patients with EGFR mutation oligometastatic NSCLC were selected by random remainder grouping method. 3DCRT combined with SBRT is effective and safer in patients with EGFR-mutant oligometastatic NSCLC, and significantly improves the patient's immune and tumor marker levels. It has a certain reference value in the clinical treatment of EGFR-mutant oligometastatic NSCLC.

EGFR-mediated Rad51 expression potentiates intrinsic resistance in prostate cancer via EMT and DNA repair pathways

AIM

To study the role of EGFR signaling in regulation of intrinsic resistance in prostate cancer.

MATERIALS AND METHODS

Radioresistant prostate carcinoma DU145 and PC-3 cells were used to study the effect of shRNA-mediated knockdown of EGFR on intrinsic radioresistance mechanisms. Semi-quantitative PCR, western blotting, growth kinetics, colony formation, transwell migration, invasion and trypan blue assays along with inhibitors erlotinib, NU7441, B02, PD98059 and LY294002 were used.

KEY FINDINGS

EGFR knock-down induced morphological alterations along with reduction in clonogenic potential and cell proliferation in DU145 cells. Migratory potential of prostate cancer cells were reduced concomitant with upregulation of epithelial marker, E-cadherin and decreased expression of mesenchymal markers, vimentin and snail. Further, EGFR knock-down decreased the expression of Rad51 and DNA-PK at mRNA as well as protein levels. Likewise, erlotinib, an EGFR inhibitor, and NU7441, a DNA-PK inhibitor increased the expression of E-cadherin and decreased the level of vimentin. Both these inhibitors also decreased the levels of DNA damage regulatory protein Rad51. Further, Rad51 inhibitor, B02, inhibited the clonogenic potential, cell migration and reduced the expression of vimentin, Ku70 and Ku80, and also, B02 radiosensitized DU145 cells. EGFR-regulated expression of Rad51 was found to be mediated via PI3K/Akt and Erk1/2 pathways.

SIGNIFICANCE

EGFR was found to regulate DNA damage repair, survival and EMT responses in prostate cancer cells through transcriptional regulation of Rad51. A novel role of EGFR-Erk1/2/Akt-Rad51 axis through modulation of EMT and DNA repair pathways in prostate cancer resistance mechanisms is suggested.

Resveratrol for targeting the tumor microenvironment and its interactions with cancer cells

Tumor resistance to therapy modalities is one of the major challenges to the eradication of cancer cells and complete treatment. Tumor includes a wide range of cancer and non-cancer cells that play key roles in the proliferation of cancer cells and suppression of anti-tumor immunity. For overcoming tumor resistance to therapy, it is important to have in-depth knowledge relating to intercellular communications within the tumor microenvironment (TME). TME includes various types of immune cells such as CD4 + T lymphocytes, cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, macrophages, and T regulatory cells (Tregs). Furthermore, some non-immune cells like cancer stem cells (CSCs), mesenchymal stem cells (MSCs), and cancer-associated fibroblasts (CAFs) are involved in the promotion of tumor growth. The interactions between these cells with cancer cells play a key role in tumor growth or inhibition. Resveratrol as a natural agent has shown the ability to modulate the immune system to potentiate anti-tumor immunity and also help to attenuate cancer cells and CSCs resistance. Thus, this review explains how resveratrol can modulate interactions within TME.